Nickel silver C75200 C75200
Copper-nickel-zinc alloy, nominal Cu 65, Ni 18, Zn 17 (UNS C75200, ASTM B122 nominal table)
Also known as UNS C75200, UNS C76400, EN 2.0740, EN name CW409J, ASTM B122, Maillechort M18 · 1 more
Nickel silver C75200 (UNS C75200, ASTM B122) is a copper-nickel-zinc alloy with a silvery colour.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Spring
680 MPa minimum
Carry current
6 %IACS
Carry heat
32 W/(m·K)
Weight
8.7 g/cm3
Melting
1060 to 1110 °C
Recipe, share of the weight
- Cu not statedCopper
- Ni not statedNickel
- Zn not statedZinc
- Pb not statedLead
- Fe not statedIron
Best for
Springs, connectors and precision optical or watch parts that need a silver colour, cold-formed strength and corrosion resistance without precious metal
Weakest at
Machinability (Fisk rates it 1 of 5, Matthey calls it rather poor) and hot working, plus the nickel content, which carries allergy and carcinogen hazard statements
Risk at a glance
- People Moderate. Nickel-containing alloy
- If it fails Moderate. Softening after heating above the annealing range
- Corrosion Moderate. Nickel silver is poorly resistant to oxidizing acids.
Quick facts: C75200
| Property | Value | Basis |
|---|---|---|
| Density | 8.7 to 8.75 g/cm³ | 2 sourced values across conditions |
| Tensile strength | 365 to 765 MPa | 8 sourced values across conditions |
| Young's modulus | 135 GPa | 1 sourced value |
| Thermal conductivity | 32 W/(m·K) | 1 sourced value |
| Thermal expansion (CTE) | 17.7 ppm/K | 1 sourced value |
| Melting point | 1,060 to 1,110 °C | 1 sourced value |
| Specific heat | 380 J/(kg·K) | 1 sourced value |
What is the density of Nickel silver C75200?
Nickel silver C75200 has a density of 8.7 to 8.75 g/cm³. The range covers 2 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the thermal conductivity of Nickel silver C75200?
Nickel silver C75200 has a thermal conductivity of 32 W/(m·K). The source and test conditions are listed in the properties table on this page.
What is the coefficient of thermal expansion of Nickel silver C75200?
Nickel silver C75200 has a coefficient of thermal expansion of 17.7 ppm/K. The source and test conditions are listed in the properties table on this page.
What is the melting point of Nickel silver C75200?
Nickel silver C75200 has a melting point of 1,060 to 1,110 °C. The source and test conditions are listed in the properties table on this page.
What is the tensile strength of Nickel silver C75200?
Nickel silver C75200 has a tensile strength of 365 to 765 MPa. The range covers 8 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What are the other names and codes for Nickel silver C75200?
Nickel silver C75200 is also written as UNS C75200, UNS C76400, EN 2.0740, EN name CW409J, ASTM B122, Maillechort M18. Each code is printed in the source listed beside it in the designations table.
What is Nickel silver C75200 used for?
Uses recorded in the sources include Relay springs and hinges for glasses; Connectors, resistors and electrical contacts; Optical frames and parts.
Why it exists
Nickel silver is chosen for its silver colour, cold-forming strength and corrosion resistance, without precious metal. Matthey names relay springs, connectors and watch-industry parts, and Fisk names springs, optical frames and resistors. Matthey rates cold forming as excellent and hot forming as limited. The density is 8.7 g/cm3 and the electrical conductivity is 6 %IACS when annealed.
Where it's used
Relay springs and glasses hinges
Matthey lists relay springs, hinges for glasses, connectors, watch-industry components and pressure membranes as typical uses. Fisk lists springs among its applications.
Connectors, resistors and contacts
Fisk lists resistors and contacts; Matthey lists connectors and parts for precision and electronic instruments.
Optical frames and parts
Fisk lists optical frames and parts first among its applications, and Matthey names optical instruments.
Recipe
Copper-nickel-zinc alloy, nominal Cu 65, Ni 18, Zn 17 (UNS C75200, ASTM B122 nominal table)
Nickel silver is a copper-nickel-zinc alloy with a single alpha phase (Matthey). Wikipedia gives the usual formulation as 60 % copper, 20 % nickel and 20 % zinc, and the C75200 nominal in ASTM B122 is 65 % copper, 18 % nickel and 17 % zinc.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Copper Cu | not stated | The matrix metal. It sets the colour base and most of the conductivity. |
| Nickel Ni | not stated | Gives the silvery, greyer colour (Matthey) and the corrosion resistance (Fisk and Matthey). It is also the source of the nickel hazard statements. |
| Zinc Zn | not stated | The balance element that completes the alloy. The Fisk nominal print of zinc 35 does not match its limits and is not used. |
| Lead Pb | not stated | Impurity limit only. Matthey says leaded grades such as CuNi12Zn25Pb1 are separate products for machinability. |
| Iron Fe | not stated | Impurity limit printed by both datasheets. |
Weight shares are as printed in the sources.
What it can do
Spring
680 MPa minimum
measured
Extra hard H200 strip has a minimum tensile strength of 680 MPa (Matthey). Round wire spring temper H08 is 105 ksi minimum (Fisk).
Carry current
6 %IACS
measured
Electrical conductivity is 6 %IACS in Matthey's table and 6 %IACS annealed in Fisk's table.
Carry heat
32 W/(m·K)
measured
Thermal conductivity is 32 W/m °K at 20 °C (Matthey).
Weight
8.7 g/cm3
measured
Density is 8.7 g/cm3 (Matthey). Fisk prints 0.316 lb/in3.
Melting
1060 to 1110 °C
measured
The melting range is 1060 to 1110 °C (Matthey).
How it compares
The copper profile at /profiles/copper/ covers the pure metal. Within this profile, the two suppliers print strength in different units (MPa for strip, ksi for round wire), and the strip table gives 680 MPa minimum at its hardest temper while round wire reaches 111 ksi, so the two tables should not be compared number to number.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details. Other materials are shown beside it; each was measured under its own conditions, so open its page before comparing closely. Compare every grade in the family.
| Measurement | C75200 | Cu | C360 | C954 | C630 | BeCu | C510 | C260 | Cu-Ag | CuCrZr | CuNi 70/30 | C21000 | CW614N | C521 | C655 | Cu-Te | Sn/Cu |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thermal behavior and safety | |||||||||||||||||
| Melting range, CuNi18Zn20 (Matthey) | 1060 to 1110 °C3 | 1083 °C | 954 °C | 1027 °C | 1060 °C | 870 °C | 954 to 1049 °C | 916 °C | no data | 1081 °C | 1170 to 1240 °C | 954 °C | 875 to 890 °C | 882 to 1027 °C | 971 to 1027 °C | 1080 °C | 231.9 °C |
| Thermal conductivity at 20 °C, CuNi18Zn20 (Matthey) | 32 W/(m·K)4 | 391 W/(m·K) | 116 W/(m·K) | 58.7 W/(m·K) | 63 W/(m·K) | 105 W/(m·K) | 84 W/(m·K) | 121.2 W/(m·K) | no data | 323 W/(m·K) | 29 W/(m·K) | 234 W/(m·K) | 123 W/(m·K) | 67 W/(m·K) | 36.3 W/(m.K) | 355 W/(m·K) | 66.6 W/(m·K) |
| Specific heat at 20 °C, CuNi18Zn20 (Matthey) | 380 J/(kg·K)10 | 0.394 kJ/(kg·K) | no data | 419 J/(kg·K) | 452 J/(kg·K) | no data | 0.38 J/(g·°C) | 377.1 J/(kg·K) | no data | 0.383 kJ/(kg·K) | 377 J/(kg·K) | 0.38 J/(g·K) | 380 J/(kg·K) | 0.377 kJ/(kg·K) | 376.8 J/(kg.K) | 385.5 J/(kg·K) | no data |
| Physical and electrical | |||||||||||||||||
| Density, CuNi18Zn20 (Matthey) | 8.7 g/cm³1 | 8.9 g/cm³ | 8.5 g/cm³ | 7.45 g/cm³ | 7.58 g/cm³ | 8.36 g/cm³ | 8.86 g/cm³ | 8.53 g/cm³ | no data | 8.94 g/cm³ | 8.94 g/cm³ | 8.86 g/cm³ | 8.46 g/cm³ | 8.79 g/cm³ | 8.53 g/cm³ | 8.94 g/cm³ | 7.28 g/cm³ |
| Density, C752 (Fisk) | 0.316 lb/in32 | 8.9 g/cm³ | 8.5 g/cm³ | 7.45 g/cm³ | 7.58 g/cm³ | 8.36 g/cm³ | 8.86 g/cm³ | 8.53 g/cm³ | no data | 8.94 g/cm³ | 8.94 g/cm³ | 8.86 g/cm³ | 8.46 g/cm³ | 8.79 g/cm³ | 8.53 g/cm³ | 8.94 g/cm³ | 7.28 g/cm³ |
| Electrical conductivity, CuNi18Zn20 (Matthey) | 6 %IACS6 | 58 MS/m | 26 %IACS | 13 %IACS | 7 %IACS | 25 to 30 %IACS | 15 %IACS | 28 %IACS | > 58 MS/m | > 46.4 MS/m | no data | 56 %IACS | 25 %IACS | 13 %IACS | 7 %IACS | 93 %IACS | 58 MS/m |
| Electrical conductivity, annealed C752 (Fisk) | 6 %IACS7 | 58 MS/m | 26 %IACS | 13 %IACS | 7 %IACS | 25 to 30 %IACS | 15 %IACS | 28 %IACS | > 58 MS/m | > 46.4 MS/m | no data | 56 %IACS | 25 %IACS | 13 %IACS | 7 %IACS | 93 %IACS | 58 MS/m |
| Hardness HV, soft annealed H90 strip | 90 to 125 HV20 | no data | no data | no data | 170 HV | no data | no data | no data | no data | no data | no data | no data | 100 to 160 HV | no data | no data | no data | no data |
| Hardness HV, half-hard H120 strip | 120 to 155 HV21 | no data | no data | no data | 170 HV | no data | no data | no data | no data | no data | no data | no data | 100 to 160 HV | no data | no data | no data | no data |
| Hardness HV, hard H185 strip | 185 to 210 HV22 | no data | no data | no data | 170 HV | no data | no data | no data | no data | no data | no data | no data | 100 to 160 HV | no data | no data | no data | no data |
| Other measurements | |||||||||||||||||
| Linear coefficient of thermal expansion, CuNi18Zn20 (Matthey) | 17.7 ppm/K5 | 17.6 ppm/K | 20.5 ppm/K | 16.2 ppm/K | 15 ppm/K | 17.5 ppm/K | 17.8 µm/(m·°C) | 20 ppm/K | no data | 17.1 ppm/K | 13.2 to 16.2 ppm/K | 18 ppm/K | 21.4 ppm/K | 17.4 µm/(m·°C) | 18 um/(m.°C) | 16.5 ppm/K | 22 ppm/K |
| Modulus of elasticity, CuNi18Zn20 (Matthey) | 135 GPa8 | 117 GPa | no data | 1.07×10^5 MPa | 117 GPa | 131 GPa | 110 GPa | 1.1×10^5 MPa | no data | 117 GPa | no data | 117 GPa | 97 GPa | 115 GPa | 1.03×10^5 MPa | 1.17×10^5 MPa | 50 GPa |
| Poisson ratio, CuNi18Zn20 (Matthey) | 0.34 -9 | no data | no data | no data | no data | no data | no data | no data | no data | no data | no data | 0.34 - | no data | no data | no data | no data | no data |
| Tensile strength, soft annealed H90 strip (R370) | 370 to 430 MPa11 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, half-hard H120 strip (R430) | 430 to 520 MPa12 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, three-quarter hard H150 strip (R520) | 520 to 610 MPa13 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, hard H185 strip (R610) | 610 to 700 MPa14 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, extra hard H200 strip (R680, minimum) | > 680 MPa15 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Elongation A50mm, soft annealed H90 strip | 40 %16 | 35 % | > 15 % | > 12 % | > 10 % | 20 to 75 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | > 25 % | 17 % | > 8 % | no data |
| Elongation A50mm, half-hard H120 strip | 22 %17 | 35 % | > 15 % | > 12 % | > 10 % | 20 to 75 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | > 25 % | 17 % | > 8 % | no data |
| Elongation A50mm, three-quarter hard H150 strip | 6 %18 | 35 % | > 15 % | > 12 % | > 10 % | 20 to 75 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | > 25 % | 17 % | > 8 % | no data |
| Elongation A50mm, hard H185 strip | 2 %19 | 35 % | > 15 % | > 12 % | > 10 % | 20 to 75 % | > 13 % | 62 % | > 37 % | > 10 % | 30 to 45 % | 45 % | > 20 % | > 25 % | 17 % | > 8 % | no data |
| Tensile strength, annealed C752 round wire (minimum) | 53 to 63 ksi23 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, hard H04 C752 round wire (minimum) | 99 to 111 ksi24 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
| Tensile strength, spring H08 C752 round wire (minimum) | > 105 ksi25 | 179 to 262 MPa | > 330 MPa | > 586 MPa | > 585 MPa | 410 to 590 MPa | > 485 MPa | 324 MPa | 180 N/mm2 | 480 to 560 MPa | 358 to 414 MPa | 235 MPa | > 360 MPa | 475 to 580 MPa | 538 MPa | > 260 MPa | no data |
Why choose it, and why not
Good for
- Springs, relay parts and hinges where a silver colour and a spring temper are both needed.
- Connectors and precision optical or watch parts stamped, folded or bent from strip (Matthey).
- Brazed or soldered assemblies: Fisk rates soldering and brazing as excellent (5 of 5).
Watch out for
- Machining is poor (Fisk 1 of 5, Matthey rather poor). Matthey recommends a leaded nickel silver for good machinability.
- The hard tempers have little elongation: 2 % in H185 strip.
- Nickel content gives allergy and cancer hazard statements; handle chips and dust with that in mind.
- Oxidizing acids attack the alloy (Matthey poorly resistant). No corrosion rate is printed.
Nickel silver C75200 is a silvery copper-nickel-zinc alloy with good atmospheric and saline corrosion resistance, a 6 %IACS conductivity and spring-grade tempers up to 680 MPa minimum in strip. Its machinability is poor and its nickel content carries allergy and carcinogen hazard statements. The C75200 nominal (Cu 65, Ni 18, Zn 17) and the EN CW409J grade (Cu 60.0 to 63.0) are close but not the same, and the Matthey UNS number for CW409J (C76400) conflicts with ASTM B122. No yield strength, corrosion rate or space-environment result was found in the sources read.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Other names and standards
The same grade under other systems, as datasheets and standards print them. Each code was checked against the page it comes from.
| System | Codes |
|---|---|
| UNS | C75200, C76400 |
| EN | 2.0740 |
| EN name | CW409J |
| ASTM | B122 |
| Trade name | Maillechort M18, Nickel Silver 18% |
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Density, CuNi18Zn20 (Matthey) | Value printed in the physical properties table of a manufacturer's datasheet | grade CuNi18Zn20 (CW409J)temper not statedtemperature not stated | — |
| 2 | Density, C752 (Fisk) | Value printed in a supplier's physical properties table; the page prints no metric density | grade C752 (Fisk 18 % nickel silver)temper not statedtemperature not statedunit in source 0.316 lb/in3 (the only density printed) | — |
| 3 | Melting range, CuNi18Zn20 (Matthey) | Range printed in the physical properties table of a manufacturer's datasheet | grade CuNi18Zn20 (CW409J)pressure not stated | — |
| 4 | Thermal conductivity at 20 °C, CuNi18Zn20 (Matthey) | Value printed in the physical properties table; the unit is printed as W/m °K, the same as W/(m·K) | grade CuNi18Zn20 (CW409J)temperature 20 °Ctemper not statedunit in source W/m °K | — |
| 5 | Linear coefficient of thermal expansion, CuNi18Zn20 (Matthey) | Printed as 10^-6 per °C; that is the same unit as ppm/K, so the number is copied without conversion | grade CuNi18Zn20 (CW409J)temperature not statedunit in source 10^-6 per °C | — |
| 6 | Electrical conductivity, CuNi18Zn20 (Matthey) | Value printed in the physical properties table; electrical_conductivity is not in the property canon (see gaps) | grade CuNi18Zn20 (CW409J)temperature not statedtemper not stated | — |
| 7 | Electrical conductivity, annealed C752 (Fisk) | Value printed in the physical properties table of a supplier's datasheet | grade C752 (Fisk 18 % nickel silver)temper annealedtemperature 68 °F as printed | — |
| 8 | Modulus of elasticity, CuNi18Zn20 (Matthey) | Printed as kN/mm2 in a datasheet table; 1 kN/mm2 equals 1 GPa, so the number is copied without conversion | grade CuNi18Zn20 (CW409J)temper not statedtemperature not statedunit in source 135 kN/mm2 | — |
| 9 | Poisson ratio, CuNi18Zn20 (Matthey) | Value printed in the physical properties table of a manufacturer's datasheet | grade CuNi18Zn20 (CW409J)temperature not statedtemper not stated | — |
| 10 | Specific heat at 20 °C, CuNi18Zn20 (Matthey) | Value printed in the physical properties table of a manufacturer's datasheet | grade CuNi18Zn20 (CW409J)temperature 20 °Cunit in source J/(kg.K) | — |
| 11 | Tensile strength, soft annealed H90 strip (R370) | Range printed in the mechanical properties table of strip; the N/mm2 value is copied as printed, which equals MPa | grade CuNi18Zn20 (CW409J)temper H90, soft annealed (R370)product form stripunit in source N/mm2 | — |
| 12 | Tensile strength, half-hard H120 strip (R430) | Range printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H120, half hard (R430)product form stripunit in source N/mm2 | — |
| 13 | Tensile strength, three-quarter hard H150 strip (R520) | Range printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H150, three-quarter hard (R520)product form stripunit in source N/mm2 | — |
| 14 | Tensile strength, hard H185 strip (R610) | Range printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H185, hard (R610)product form stripunit in source N/mm2 | — |
| 15 | Tensile strength, extra hard H200 strip (R680, minimum) | Minimum value printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H200, extra hard (R680)product form stripmeasure minimumunit in source N/mm2 | — |
| 16 | Elongation A50mm, soft annealed H90 strip | Value printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H90, soft annealedproduct form stripgauge length A50mm | — |
| 17 | Elongation A50mm, half-hard H120 strip | Value printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H120, half hardproduct form stripgauge length A50mm | — |
| 18 | Elongation A50mm, three-quarter hard H150 strip | Value printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H150, three-quarter hardproduct form stripgauge length A50mm | — |
| 19 | Elongation A50mm, hard H185 strip | Value printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H185, hardproduct form stripgauge length A50mm | — |
| 20 | Hardness HV, soft annealed H90 strip | Range printed in the mechanical properties table of strip; hardness_vickers is not in the property canon (see gaps) | grade CuNi18Zn20 (CW409J)temper H90, soft annealedproduct form strip | — |
| 21 | Hardness HV, half-hard H120 strip | Range printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H120, half hardproduct form strip | — |
| 22 | Hardness HV, hard H185 strip | Range printed in the mechanical properties table of strip | grade CuNi18Zn20 (CW409J)temper H185, hardproduct form strip | — |
| 23 | Tensile strength, annealed C752 round wire (minimum) | Range printed in the round wire temper table of a supplier's datasheet; ksi is copied as printed | grade C752 (Fisk 18 % nickel silver)temper annealedproduct form round wireunit in source 53.0 to 63.0 ksi | — |
| 24 | Tensile strength, hard H04 C752 round wire (minimum) | Range printed in the round wire temper table of a supplier's datasheet | grade C752 (Fisk 18 % nickel silver)temper H04, hardproduct form round wire | — |
| 25 | Tensile strength, spring H08 C752 round wire (minimum) | Minimum value printed in the round wire temper table of a supplier's datasheet | grade C752 (Fisk 18 % nickel silver)temper H08, springproduct form round wiremeasure minimum | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Atmosphere, organic compounds, and neutral or alkaline saline solutions | low | Nickel silver has good resistance to atmospheric corrosion and to neutral or alkaline saline solutions.1 |
| Oxidizing acids | moderate | Nickel silver is poorly resistant to oxidizing acids.2 |
| Ammonia or amine atmospheres with tensile stress (stress corrosion cracking) | low | Stress corrosion cracking sensitivity is much lower than for brass.3 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Atmosphere, organic compounds, and neutral or alkaline saline solutions | Matthey says the CuNi18Zn20 grade has good resistance to atmospheric corrosion, organic compounds and neutral and alkaline saline solutions. Fisk says the C752 alloy combines corrosion resistance with strength and a lustrous silver colour. No exposure time, corrosion rate or test is printed in either source. | basis qualitative statements in datasheets; no rate, exposure time or test standard is printedgrade CuNi18Zn20 (CW409J) for the Matthey statement |
| 2 | Oxidizing acids | Matthey says the alloy is poorly resistant to oxidizing acids. The datasheet names no acid, concentration or temperature. | basis qualitative statement; no acid, concentration or temperature is namedgrade CuNi18Zn20 (CW409J) |
| 3 | Ammonia or amine atmospheres with tensile stress (stress corrosion cracking) | Matthey says the sensitivity of CuNi18Zn20 to stress corrosion cracking is much lower than that of brass. No threshold stress, time to crack or test environment is printed for nickel silver. | basis qualitative comparison with brass; no threshold stress or time to crack is printedgrade CuNi18Zn20 (CW409J) |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The nickel in this alloy is the main health concern in the sources. PubChem gives the nickel hazard statements, and the Matthey and Fisk limits show how much nickel the alloy holds.
- Allergy
- PubChem's GHS notifications for nickel include H317, May cause an allergic skin reaction (99.9 % of notifications), and H334 for respiratory allergy in some notifications.
- Cancer
- PubChem's GHS notifications list H351, Suspected of causing cancer (72.9 %), and H350 (22.5 %) in some. The alloy itself is not classified in the sources read.
- Nickel content
- The CuNi18Zn20 grade holds 17.0 to 19.0 % nickel (Matthey) and the C752 grade 16.5 to 19.5 % (Fisk). ASTM B122 gives 18 % nominal for C75200.
If it fails
The failure routes in these sources are heat that removes the temper, forming of the hard tempers, and the machining limits.
- Heat softening
- Heating above the Fisk annealing range (1100 to 1400 °F) removes cold-work strength, so the part falls back toward the annealed value.
- Hard temper
- Hard H185 strip stretches only 2 % (A50mm) against 40 % soft annealed, so bending needs a softer temper.
- Machining
- Fisk rates machinability 1 of 5 and Matthey calls it rather poor, so high-volume machining is a poor fit.
Handling and storage
- Pick the temper
- Strip tempers run from 370 to 430 MPa soft annealed to 680 MPa minimum extra hard (Matthey). Round wire runs from 53.0 to 63.0 ksi annealed to 99.0 to 111 ksi hard (Fisk).
- Stress relief
- Stress-relieve at 300 to 350 °C after cold forming to reduce internal stress, as Matthey advises.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Softening after heating above the annealing rangemoderate severity | Heating a cold-worked part above the annealing range printed by Fisk (1100 to 1400 °F)The temper is lost and the part falls back toward the annealed strength (53.0 to 63.0 ksi round wire, Fisk). The softening consequence is an inference from the printed ranges. |
| Cracking when hard tempers are bent or formedmoderate severity | Forming or bending strip in the hard H185 or extra hard H200 temperElongation falls to 2 % in hard H185 strip (A50mm), against 40 % soft annealed. Matthey prints no forming limit. |
| Poor machinability and hot workinglow severity | Machining or hot forming the alloyFisk rates machinability 1 of 5 (poor) and hot working 1 of 5 (poor). Matthey says machinability is rather poor and hot formability is limited. |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Laser-welded assemblies | Matthey says the alloy can be brazed or welded, but its weldability by laser is not good. |
Handling and storage
- Anneal at 620 to 700 °C (Matthey) or within the 1100 to 1400 °F range (Fisk).
- Stress-relieve at 300 to 350 °C after cold forming to reduce internal stress (Matthey).
- Pick the temper from the strip table: soft annealed H90 gives 370 to 430 MPa, half-hard H120 430 to 520 MPa, three-quarter hard H150 520 to 610 MPa, hard H185 610 to 700 MPa, extra hard H200 680 MPa minimum (Matthey).
- Lead is an impurity limit only. Chips and dust should be handled as nickel-containing material; this handling advice is an inference from the nickel hazard statements, not a printed instruction.
Mitigations
- Matthey recommends a leaded nickel silver, CuNi12Zn25Pb1 (B420), where good machinability is needed.
- Use the stress-relief heat treatment at 300 to 350 °C after cold work to decrease internal stress (Matthey).
Supply and geography
How common the raw materials are and where they come from.
Copper (mine production, copper content, 2025e), about 60 to 66 % of the alloy
- Top producers (2025)
- Chile 23%, Congo (Kinshasa) 13.9%, Peru 11.7%, China 7.8%, Russia 5.7%
- Critical mineral lists
- US: listed
- Recycling
- USGS: brass and wire-rod mills accounted for approximately 80% of the total copper recovered from scrap, and copper recovered from scrap contributed about 30% of the U.S. copper supply.
Nickel (mine production, nickel content, 2025e), 16.5 to 19.5 % of the alloy
- Top producers (2025)
- Indonesia 66.7%, Philippines 6.9%, Russia 5.1%, Canada 3.6%, New Caledonia 3.6%
- Recycling
- USGS: nickel recovered from scrap accounted for approximately 60% of apparent consumption in 2025, and most secondary nickel was stainless-steel scrap.
- Substitutes
- USGS: low-nickel, duplex, or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments.
Zinc (mine production, zinc content, 2025e), about 17 % of the alloy
- Top producers (2025)
- China 31.5%, Peru 11.5%, Australia 8.5%, India 6.7%, Mexico 6%
- Recycling
- USGS: refined zinc produced in the United States was recovered from secondary materials, including galvanizing residues and crude zinc oxide from electric arc furnace dust.
- Substitutes
- USGS: aluminum and plastics substitute for galvanized sheet in automobiles; many elements are substitutes for zinc in chemical, electronic and pigment uses. The summary names no substitute for zinc in nickel silver.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
spore: profile
id: nickel-silver
spore_version: 0.2
family: copper-alloys
name: Nickel silver C75200
abbreviation: C75200
role: copper-nickel-zinc spring and optical alloy
category: metals
type: copper-alloys
summary: |
Nickel silver C75200 (UNS C75200, ASTM B122) is a copper-nickel-zinc alloy with a silvery colour. ASTM B122 prints its nominal composition as 65 % copper, 18 % nickel and 17 % zinc. The EN grade CW409J (CuNi18Zn20, DIN 2.0740) is close but not identical: Matthey prints 60.0 to 63.0 % copper for it. Matthey gives a density of 8.7 g/cm3 and a modulus of elasticity of 135 GPa, and its strip tensile strength runs from 370 to 430 MPa soft annealed to 680 MPa minimum extra hard. Fisk gives an electrical conductivity of 6 %IACS when annealed and round-wire tensile strengths from 53.0 to 63.0 ksi annealed to 99.0 to 111 ksi hard. Matthey says the alloy resists atmospheric corrosion and neutral and alkaline saline solutions, is poorly resistant to oxidizing acids, and is much less prone to stress corrosion cracking than brass. Its nickel content is the health concern: PubChem's GHS notifications for nickel include H317 (allergic skin reaction) and H351 (suspected carcinogen).
best_for: Springs, connectors and precision optical or watch parts that need a silver colour, cold-formed strength and corrosion resistance without precious metal
weakest_at: Machinability (Fisk rates it 1 of 5, Matthey calls it rather poor) and hot working, plus the nickel content, which carries allergy and carcinogen hazard statements
identity:
formula: Copper-nickel-zinc alloy, nominal Cu 65, Ni 18, Zn 17 (UNS C75200, ASTM B122 nominal table)
source: astm-b122
where: 'ASTM B122 nominal composition table, row C75200 (Cu 65, Ni 18, Zn 17). Composition limits: Matthey CuNi18Zn20 (CW409J) Cu 60.0 to 63.0, Ni 17.0 to 19.0, Fe up to 0.30, Mn up to 0.50, Pb up to 0.03, Sn up to 0.03, Zn balance. Fisk C752 (C75200 family) Cu 63.0 to 66.5, Ni 16.5 to 19.5, Pb 0.05 max, Fe 0.25 max, Mn 0.50 max, Zn remainder.'
designations:
- system: UNS
code: C75200
source: astm-b122
where: Nominal composition table, row C75200; the UNS list in the scope names C75200
- system: EN name
code: CW409J
source: matthey-cuni18zn20
where: Designation row, EN Nr. column, for CuNi18Zn20
- system: EN
code: '2.0740'
source: matthey-cuni18zn20
where: Designation row, DIN column, for CuNi18Zn20
- system: UNS
code: C76400
note: Matthey pairs this UNS number with CuNi18Zn20 (CW409J). ASTM B122 does not list C76400 and gives C75200 for the 65-18-17 nominal, so the two sources conflict; see gaps
source: matthey-cuni18zn20
where: Designation row, UNS (ASTM) column
- system: ASTM
code: B122
note: copper-nickel-zinc alloy (nickel silver) plate, sheet, strip and rolled bar
source: fisk-c752
where: Specifications list
- system: Trade name
code: Maillechort M18
source: matthey-cuni18zn20
where: 'Page title: CuNi18Zn20, Maillechort M18'
- system: Trade name
code: Nickel Silver 18%
source: fisk-c752
where: 'Page title: C752 Nickel Silver 18% Alloy Wire'
tags:
environments: []
stresses: []
applications:
- mechanisms
- electronics-and-chips
- optics-and-cameras
properties:
- benchmark: density
label: Density, CuNi18Zn20 (Matthey)
value: 8.7
unit: g/cm3
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: not stated
temperature: not stated
method: Value printed in the physical properties table of a manufacturer's datasheet
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Density row
- benchmark: density
label: Density, C752 (Fisk)
value: 0.316
unit: lb/in3
scope: material
conditions:
grade: C752 (Fisk 18 % nickel silver)
temper: not stated
temperature: not stated
unit_in_source: 0.316 lb/in3 (the only density printed)
method: Value printed in a supplier's physical properties table; the page prints no metric density
status: ground
source: fisk-c752
where: Physical Properties table, Density row
- benchmark: melting_point
label: Melting range, CuNi18Zn20 (Matthey)
value: 1060
value_high: 1110
bound: range
unit: °C
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
pressure: not stated
method: Range printed in the physical properties table of a manufacturer's datasheet
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Melting point / Melting range row
- benchmark: thermal_conductivity
label: Thermal conductivity at 20 °C, CuNi18Zn20 (Matthey)
value: 32
unit: W/(m·K)
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temperature: 20 °C
temper: not stated
unit_in_source: W/m °K
method: Value printed in the physical properties table; the unit is printed as W/m °K, the same as W/(m·K)
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Thermal conductivity at 20 °C row
- benchmark: cte
label: Linear coefficient of thermal expansion, CuNi18Zn20 (Matthey)
value: 17.7
unit: ppm/K
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temperature: not stated
unit_in_source: 10^-6 per °C
method: Printed as 10^-6 per °C; that is the same unit as ppm/K, so the number is copied without conversion
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Linear dilatation coefficient row
- benchmark: electrical_conductivity
label: Electrical conductivity, CuNi18Zn20 (Matthey)
value: 6
unit: '%IACS'
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temperature: not stated
temper: not stated
method: Value printed in the physical properties table; electrical_conductivity is not in the property canon (see gaps)
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Electrical conductivity % IACS row
- benchmark: electrical_conductivity
label: Electrical conductivity, annealed C752 (Fisk)
value: 6
unit: '%IACS'
scope: material
conditions:
grade: C752 (Fisk 18 % nickel silver)
temper: annealed
temperature: 68 °F as printed
method: Value printed in the physical properties table of a supplier's datasheet
status: ground
source: fisk-c752
where: Physical Properties table, Electrical Conductivity (Annealed) row
- benchmark: elastic_modulus
label: Modulus of elasticity, CuNi18Zn20 (Matthey)
value: 135
unit: GPa
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: not stated
temperature: not stated
unit_in_source: 135 kN/mm2
method: Printed as kN/mm2 in a datasheet table; 1 kN/mm2 equals 1 GPa, so the number is copied without conversion
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Modulus of elasticity row
- benchmark: poissons_ratio
label: Poisson ratio, CuNi18Zn20 (Matthey)
value: 0.34
unit: '-'
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temperature: not stated
temper: not stated
method: Value printed in the physical properties table of a manufacturer's datasheet
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Poisson ratio row
- benchmark: specific_heat
label: Specific heat at 20 °C, CuNi18Zn20 (Matthey)
value: 380
unit: J/(kg·K)
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temperature: 20 °C
unit_in_source: J/(kg.K)
method: Value printed in the physical properties table of a manufacturer's datasheet
status: ground
source: matthey-cuni18zn20
where: Physical properties table, Specific heat at 20 °C row
- benchmark: ultimate_tensile_strength
label: Tensile strength, soft annealed H90 strip (R370)
value: 370
value_high: 430
bound: range
unit: MPa
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H90, soft annealed (R370)
product_form: strip
unit_in_source: N/mm2
method: Range printed in the mechanical properties table of strip; the N/mm2 value is copied as printed, which equals MPa
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R370 H90 soft annealed, column Rm (N/mm2)
- benchmark: ultimate_tensile_strength
label: Tensile strength, half-hard H120 strip (R430)
value: 430
value_high: 520
bound: range
unit: MPa
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H120, half hard (R430)
product_form: strip
unit_in_source: N/mm2
method: Range printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R430 H120 half hard, column Rm (N/mm2)
- benchmark: ultimate_tensile_strength
label: Tensile strength, three-quarter hard H150 strip (R520)
value: 520
value_high: 610
bound: range
unit: MPa
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H150, three-quarter hard (R520)
product_form: strip
unit_in_source: N/mm2
method: Range printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R520 H150 three-quarter hard, column Rm (N/mm2)
- benchmark: ultimate_tensile_strength
label: Tensile strength, hard H185 strip (R610)
value: 610
value_high: 700
bound: range
unit: MPa
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H185, hard (R610)
product_form: strip
unit_in_source: N/mm2
method: Range printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R610 H185 hard, column Rm (N/mm2)
- benchmark: ultimate_tensile_strength
label: Tensile strength, extra hard H200 strip (R680, minimum)
value: 680
bound: lower
unit: MPa
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H200, extra hard (R680)
product_form: strip
measure: minimum
unit_in_source: N/mm2
method: Minimum value printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R680 H200 extra hard, column Rm (N/mm2)
- benchmark: elongation
label: Elongation A50mm, soft annealed H90 strip
value: 40
unit: '%'
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H90, soft annealed
product_form: strip
gauge_length: A50mm
method: Value printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R370 H90, column A50mm (%)
- benchmark: elongation
label: Elongation A50mm, half-hard H120 strip
value: 22
unit: '%'
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H120, half hard
product_form: strip
gauge_length: A50mm
method: Value printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R430 H120, column A50mm (%)
- benchmark: elongation
label: Elongation A50mm, three-quarter hard H150 strip
value: 6
unit: '%'
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H150, three-quarter hard
product_form: strip
gauge_length: A50mm
method: Value printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R520 H150, column A50mm (%)
- benchmark: elongation
label: Elongation A50mm, hard H185 strip
value: 2
unit: '%'
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H185, hard
product_form: strip
gauge_length: A50mm
method: Value printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R610 H185, column A50mm (%)
- benchmark: hardness_vickers
label: Hardness HV, soft annealed H90 strip
value: 90
value_high: 125
bound: range
unit: HV
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H90, soft annealed
product_form: strip
method: Range printed in the mechanical properties table of strip; hardness_vickers is not in the property canon (see gaps)
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R370 H90, column Hardness HV
- benchmark: hardness_vickers
label: Hardness HV, half-hard H120 strip
value: 120
value_high: 155
bound: range
unit: HV
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H120, half hard
product_form: strip
method: Range printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R430 H120, column Hardness HV
- benchmark: hardness_vickers
label: Hardness HV, hard H185 strip
value: 185
value_high: 210
bound: range
unit: HV
scope: material
conditions:
grade: CuNi18Zn20 (CW409J)
temper: H185, hard
product_form: strip
method: Range printed in the mechanical properties table of strip
status: ground
source: matthey-cuni18zn20
where: Mechanical properties of strips table, row R610 H185, column Hardness HV
- benchmark: ultimate_tensile_strength
label: Tensile strength, annealed C752 round wire (minimum)
value: 53
value_high: 63
bound: range
unit: ksi
scope: material
conditions:
grade: C752 (Fisk 18 % nickel silver)
temper: annealed
product_form: round wire
unit_in_source: 53.0 to 63.0 ksi
method: Range printed in the round wire temper table of a supplier's datasheet; ksi is copied as printed
status: ground
source: fisk-c752
where: Round Wire table, Annealed row, Tensile strength (ksi) Min and Max
- benchmark: ultimate_tensile_strength
label: Tensile strength, hard H04 C752 round wire (minimum)
value: 99
value_high: 111
bound: range
unit: ksi
scope: material
conditions:
grade: C752 (Fisk 18 % nickel silver)
temper: H04, hard
product_form: round wire
method: Range printed in the round wire temper table of a supplier's datasheet
status: ground
source: fisk-c752
where: Round Wire table, Hard H04 row, Tensile strength (ksi) Min and Max
- benchmark: ultimate_tensile_strength
label: Tensile strength, spring H08 C752 round wire (minimum)
value: 105
bound: lower
unit: ksi
scope: material
conditions:
grade: C752 (Fisk 18 % nickel silver)
temper: H08, spring
product_form: round wire
measure: minimum
method: Minimum value printed in the round wire temper table of a supplier's datasheet
status: ground
source: fisk-c752
where: Round Wire table, Spring H08 row, Tensile strength (ksi) Min
corrosion:
- environment: Atmosphere, organic compounds, and neutral or alkaline saline solutions
headline: Nickel silver has good resistance to atmospheric corrosion and to neutral or alkaline saline solutions.
effect: Matthey says the CuNi18Zn20 grade has good resistance to atmospheric corrosion, organic compounds and neutral and alkaline saline solutions. Fisk says the C752 alloy combines corrosion resistance with strength and a lustrous silver colour. No exposure time, corrosion rate or test is printed in either source.
rating: low
conditions:
basis: qualitative statements in datasheets; no rate, exposure time or test standard is printed
grade: CuNi18Zn20 (CW409J) for the Matthey statement
source: matthey-cuni18zn20
where: Main technical properties and features, first paragraph
- environment: Oxidizing acids
headline: Nickel silver is poorly resistant to oxidizing acids.
effect: Matthey says the alloy is poorly resistant to oxidizing acids. The datasheet names no acid, concentration or temperature.
rating: moderate
conditions:
basis: qualitative statement; no acid, concentration or temperature is named
grade: CuNi18Zn20 (CW409J)
source: matthey-cuni18zn20
where: Main technical properties and features, first paragraph
- environment: Ammonia or amine atmospheres with tensile stress (stress corrosion cracking)
headline: Stress corrosion cracking sensitivity is much lower than for brass.
effect: Matthey says the sensitivity of CuNi18Zn20 to stress corrosion cracking is much lower than that of brass. No threshold stress, time to crack or test environment is printed for nickel silver.
rating: low
conditions:
basis: qualitative comparison with brass; no threshold stress or time to crack is printed
grade: CuNi18Zn20 (CW409J)
source: matthey-cuni18zn20
where: Main technical properties and features, first paragraph
risks:
hazards:
- text: PubChem's GHS notifications for nickel (CID 935) include H317 May cause an allergic skin reaction (99.9 % of notifications) and H351 Suspected of causing cancer (72.9 %), H350 May cause cancer (22.5 %), and also list H334, H372 and H360F in some notifications. No SDS for the alloy itself was read.
ghs: []
source: pubchem-nickel
where: Safety and Hazards, GHS Classification, CID 935 (ECHA aggregated notifications)
- text: Nickel is 17.0 to 19.0 % of the CuNi18Zn20 grade (Matthey) and 16.5 to 19.5 % of the C752 grade (Fisk), so nickel is the main hazard element. ASTM B122 nominal for C75200 is 18 % nickel.
ghs: []
source: matthey-cuni18zn20
where: Chemical composition table, Ni row
- text: 'Lead is an impurity: Matthey gives 0.03 % maximum and Fisk gives 0.05 % maximum. The sources read do not add lead to this grade.'
ghs: []
source: fisk-c752
where: Chemical Composition Limits, Pb row
failure_risks:
- mode: Softening after heating above the annealing range
trigger: Heating a cold-worked part above the annealing range printed by Fisk (1100 to 1400 °F)
consequence: The temper is lost and the part falls back toward the annealed strength (53.0 to 63.0 ksi round wire, Fisk). The softening consequence is an inference from the printed ranges.
severity: moderate
source: fisk-c752
where: Physical Properties table, Annealing Range rows; Round Wire table, Annealed row
- mode: Cracking when hard tempers are bent or formed
trigger: Forming or bending strip in the hard H185 or extra hard H200 temper
consequence: Elongation falls to 2 % in hard H185 strip (A50mm), against 40 % soft annealed. Matthey prints no forming limit.
severity: moderate
source: matthey-cuni18zn20
where: Mechanical properties of strips table, rows R370 H90 and R610 H185, column A50mm (%)
- mode: Poor machinability and hot working
trigger: Machining or hot forming the alloy
consequence: Fisk rates machinability 1 of 5 (poor) and hot working 1 of 5 (poor). Matthey says machinability is rather poor and hot formability is limited.
severity: low
source: fisk-c752
where: Fabrication Index table, Machinability and Hot Worked rows
side_effects:
- text: Matthey says the alloy can be brazed or welded, but its weldability by laser is not good.
affects: Laser-welded assemblies
source: matthey-cuni18zn20
where: Main technical properties and features, paragraph on joining
handling:
- text: Anneal at 620 to 700 °C (Matthey) or within the 1100 to 1400 °F range (Fisk).
source: matthey-cuni18zn20
where: Main technical properties and features, annealing sentence
- text: Stress-relieve at 300 to 350 °C after cold forming to reduce internal stress (Matthey).
source: matthey-cuni18zn20
where: Main technical properties and features, last sentence
- text: 'Pick the temper from the strip table: soft annealed H90 gives 370 to 430 MPa, half-hard H120 430 to 520 MPa, three-quarter hard H150 520 to 610 MPa, hard H185 610 to 700 MPa, extra hard H200 680 MPa minimum (Matthey).'
source: matthey-cuni18zn20
where: Mechanical properties of strips table
- text: Lead is an impurity limit only. Chips and dust should be handled as nickel-containing material; this handling advice is an inference from the nickel hazard statements, not a printed instruction.
source: pubchem-nickel
where: Safety and Hazards, GHS Classification, CID 935
mitigations:
- text: Matthey recommends a leaded nickel silver, CuNi12Zn25Pb1 (B420), where good machinability is needed.
source: matthey-cuni18zn20
where: Main technical properties and features, machinability sentence
- text: Use the stress-relief heat treatment at 300 to 350 °C after cold work to decrease internal stress (Matthey).
source: matthey-cuni18zn20
where: Main technical properties and features, last sentence
uses:
- application: mechanisms
device: Relay springs and hinges for glasses
example: Matthey lists relay springs and hinges for glasses as typical uses; Fisk lists springs among its applications.
source: matthey-cuni18zn20
where: Typical uses paragraph
- application: electronics-and-chips
device: Connectors, resistors and electrical contacts
example: Matthey lists connectors and parts for precision and electronic instruments; Fisk lists resistors and contacts.
source: fisk-c752
where: Introduction, Applications sentence
- application: optics-and-cameras
device: Optical frames and parts
example: Fisk lists optical frames and parts first among its applications; Matthey lists optical instruments and watch-making parts.
source: fisk-c752
where: Introduction, Applications sentence
supply:
- subject: Copper (mine production, copper content, 2025e), about 60 to 66 % of the alloy
producers:
- country: Chile
share_percent: 23
year: 2025
- country: Congo (Kinshasa)
share_percent: 13.9
year: 2025
- country: Peru
share_percent: 11.7
year: 2025
- country: China
share_percent: 7.8
year: 2025
- country: Russia
share_percent: 5.7
year: 2025
critical_lists:
- list: U.S. Final 2025 List of Critical Minerals (copper added, per the USGS copper summary)
listed: true
recycling: 'USGS: brass and wire-rod mills accounted for approximately 80% of the total copper recovered from scrap, and copper recovered from scrap contributed about 30% of the U.S. copper supply.'
substitutes: []
source: usgs-mcs2026-copper
where: World Mine and Refinery Production and Reserves table, mine production 2025e (world total 23,000 thousand t; shares calculated by Space Mushroom from the printed values 5,300, 3,200, 2,700, 1,800 and 1,300 thousand t); Recycling paragraph; Critical minerals paragraph
- subject: Nickel (mine production, nickel content, 2025e), 16.5 to 19.5 % of the alloy
producers:
- country: Indonesia
share_percent: 66.7
year: 2025
- country: Philippines
share_percent: 6.9
year: 2025
- country: Russia
share_percent: 5.1
year: 2025
- country: Canada
share_percent: 3.6
year: 2025
- country: New Caledonia
share_percent: 3.6
year: 2025
critical_lists: []
recycling: 'USGS: nickel recovered from scrap accounted for approximately 60% of apparent consumption in 2025, and most secondary nickel was stainless-steel scrap.'
substitutes:
- 'USGS: low-nickel, duplex, or ultrahigh-chromium stainless steels have been substituted for austenitic grades in construction; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments.'
source: usgs-mcs2026-nickel
where: World Mine Production and Reserves table, 2025e (world total rounded 3,900,000 t; shares calculated by Space Mushroom from the printed values 2,600,000, 270,000, 200,000 and 140,000 t, the last two each for Canada and New Caledonia); Domestic Production and Use, Recycling and Substitutes paragraphs
- subject: Zinc (mine production, zinc content, 2025e), about 17 % of the alloy
producers:
- country: China
share_percent: 31.5
year: 2025
- country: Peru
share_percent: 11.5
year: 2025
- country: Australia
share_percent: 8.5
year: 2025
- country: India
share_percent: 6.7
year: 2025
- country: Mexico
share_percent: 6
year: 2025
critical_lists: []
recycling: 'USGS: refined zinc produced in the United States was recovered from secondary materials, including galvanizing residues and crude zinc oxide from electric arc furnace dust.'
substitutes:
- 'USGS: aluminum and plastics substitute for galvanized sheet in automobiles; many elements are substitutes for zinc in chemical, electronic and pigment uses. The summary names no substitute for zinc in nickel silver.'
source: usgs-mcs2026-zinc
where: World Mine Production and Reserves table, 2025e (world total rounded 13,000 thousand t; shares calculated by Space Mushroom from the printed values 4,100, 1,500, 1,100, 870 and 780 thousand t); Recycling and Substitutes paragraphs
documents:
- title: 'Lamineries Matthey: CuNi18Zn20 (Maillechort M18) technical datasheet'
type: datasheet
url: https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf
- title: 'Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire datasheet'
type: datasheet
url: https://fiskalloy.com/pdf/c75200/
- title: 'ASTM B122/B122M: copper-nickel-zinc alloy (nickel silver) plate, sheet, strip and rolled bar, UNS list and nominal composition'
type: standard
url: https://store.astm.org/b0122_b0122m-16.html
year: 2016
- title: 'Wikipedia: Nickel silver (composition and history only)'
type: database
url: https://en.wikipedia.org/wiki/Nickel_silver
- title: 'PubChem: Nickel (CID 935), Safety and Hazards, GHS classification'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
- title: 'USGS Mineral Commodity Summaries 2026: Copper'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Zinc'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zinc.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Nickel'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
year: 2026
gaps:
- 'Designations conflict: Matthey prints UNS C76400 for CuNi18Zn20 (CW409J, Cu 60.0 to 63.0), but ASTM B122 does not list C76400 and prints C75200 for the 65-18-17 nominal (Cu 65, Ni 18, Zn 17). The profile lists both as printed and does not treat C76400 as the same grade as C75200. Someone should check which UNS number the EN CW409J grade maps to before the two are linked in search.'
- 'Composition: the EN grade CW409J (Cu 60.0 to 63.0) and C75200 (Cu 63.0 to 66.5 per Fisk) are close but not the same range. The profile keeps both and does not average them.'
- Fisk prints a nominal zinc of 35 in its nominal composition column next to Cu 65 and Ni 18, which does not fit the zinc remainder in its limits. The nominal zinc is not used.
- Fisk prints a modulus of elasticity of 18 ksi, which is about 1000 times too low for a copper alloy and is treated as a units error. It is not recorded. Matthey's 135 GPa is used instead.
- Matthey prints an electrical resistivity of 28.7 with the unit 'cm', which cannot be read reliably as a unit (the superscript was lost). It is not recorded; Matthey's 3.3 MS/m is also not used because the %IACS value is recorded.
- No yield strength (0.2 % offset or 0.5 % extension) is printed in any source read, for strip or for round wire.
- 'No copper.org (CDA) alloy page and no MakeItFrom page could be read: copper.org returned 403 and MakeItFrom returned 403 to the fetcher. Their values are not used.'
- Hardness is in HV for strip only (Matthey). The property name hardness_vickers is not in the property canon. Fisk gives no hardness.
- electrical_conductivity is not in the property canon; the name is used as a snake_case placeholder (see the brass profile for the same case).
- Thermal conductivity and thermal expansion are from Matthey only. Fisk prints them in imperial units (19 Btu per ft2 per ft per hour per degree F, 9 per degree F over 68 to 572 F) and they are not converted or recorded.
- Nickel critical-mineral status is not read in this run (the nickel summary read has no critical-list statement), so critical_lists is empty for nickel. Zinc's status is also not read.
- 'Hazards: the GHS codes are for nickel (PubChem CID 935), not for the alloy. ATSDR''s nickel ToxFAQ could not be read (the fetched page was the portal landing page), so the carcinogen and allergy statements rest on PubChem''s GHS notifications and not on ATSDR.'
- No occupational exposure limit for nickel or nickel silver was read.
- No corrosion rate, test time or threshold stress for nickel silver was printed in the sources read, and no dezincification data was read.
- No space-environment data (outgassing, atomic oxygen, cold welding, radiation) was read, so tags.environments is empty and the habitats-and-suits application is not used.
- 'No CAS number is recorded: the alloy is identified by its UNS number, and no source read gives a CAS number for the alloy.'
- No media (images) were added to this profile; no image was fetched or checked in this run.
- Wikipedia was used for the composition formulation (60 % copper, 20 % nickel, 20 % zinc) and history only, as the brief requires; its use statements were not used.
- Specific heat is from Matthey at 20 °C only; the temperature dependence and the Poisson ratio at temperature were not read.
sources:
astm-b122:
title: 'ASTM B122/B122M: copper-nickel-zinc alloy (nickel silver) plate, sheet, strip and rolled bar; UNS list and nominal composition table'
url: https://store.astm.org/b0122_b0122m-16.html
kind: standard
license: Standard listing page (cited, not reproduced)
matthey-cuni18zn20:
title: 'Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table'
url: https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi18Zn20_v22E.pdf
kind: datasheet
license: Manufacturer datasheet (cited, not reproduced)
fisk-c752:
title: 'Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index'
url: https://fiskalloy.com/pdf/c75200/
kind: datasheet
license: Supplier datasheet (cited, not reproduced)
wiki-nickel-silver:
title: 'Wikipedia: Nickel silver (composition and history only)'
url: https://en.wikipedia.org/wiki/Nickel_silver
kind: web
license: CC BY-SA 4.0 (cited, not reproduced)
pubchem-nickel:
title: 'PubChem: Nickel, CID 935, Safety and Hazards, GHS classification (ECHA aggregated notifications)'
url: https://pubchem.ncbi.nlm.nih.gov/compound/Nickel
kind: database
license: PubChem public database (cited, not reproduced)
usgs-mcs2026-copper:
title: 'Mineral Commodity Summaries 2026: Copper'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-mcs2026-zinc:
title: 'Mineral Commodity Summaries 2026: Zinc'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-zinc.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-mcs2026-nickel:
title: 'Mineral Commodity Summaries 2026: Nickel'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
year: 2026
kind: report
license: public domain (USGS)
license: CC-BY-4.0
updated: '2026-10-26'
review:
status: draft
method: assistant
checked_values: 25
unreachable: 4
caveats: 6
note: 'Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable to the fetcher: copper.org (403, CDA alloy page and nickel silver page), MakeItFrom (403), suppliersonline (503), ATSDR nickel ToxFAQ (landing page only, no nickel content). Caveats: the C75200 and CW409J composition ranges differ, and the Matthey UNS number for CW409J (C76400) is not in ASTM B122; the Fisk modulus (18 ksi) is a units error and is not recorded; the Fisk nominal zinc (35) does not fit its own limits; hazard statements are for nickel from PubChem and not from an SDS for the alloy; no yield strengths or corrosion rates were read.'
story:
risk_groups:
- title: For people
lead: The nickel in this alloy is the main health concern in the sources. PubChem gives the nickel hazard statements, and the Matthey and Fisk limits show how much nickel the alloy holds.
level: 2
verdict: Nickel-containing alloy
points:
- label: Allergy
line: PubChem's GHS notifications for nickel include H317, May cause an allergic skin reaction (99.9 % of notifications), and H334 for respiratory allergy in some notifications.
- label: Cancer
line: PubChem's GHS notifications list H351, Suspected of causing cancer (72.9 %), and H350 (22.5 %) in some. The alloy itself is not classified in the sources read.
- label: Nickel content
line: The CuNi18Zn20 grade holds 17.0 to 19.0 % nickel (Matthey) and the C752 grade 16.5 to 19.5 % (Fisk). ASTM B122 gives 18 % nominal for C75200.
- title: If it fails
lead: The failure routes in these sources are heat that removes the temper, forming of the hard tempers, and the machining limits.
points:
- label: Heat softening
line: Heating above the Fisk annealing range (1100 to 1400 °F) removes cold-work strength, so the part falls back toward the annealed value.
- label: Hard temper
line: Hard H185 strip stretches only 2 % (A50mm) against 40 % soft annealed, so bending needs a softer temper.
- label: Machining
line: Fisk rates machinability 1 of 5 and Matthey calls it rather poor, so high-volume machining is a poor fit.
- title: Handling and storage
points:
- label: Pick the temper
line: Strip tempers run from 370 to 430 MPa soft annealed to 680 MPa minimum extra hard (Matthey). Round wire runs from 53.0 to 63.0 ksi annealed to 99.0 to 111 ksi hard (Fisk).
- label: Stress relief
line: Stress-relieve at 300 to 350 °C after cold forming to reduce internal stress, as Matthey advises.
why: Nickel silver is chosen for its silver colour, cold-forming strength and corrosion resistance, without precious metal. Matthey names relay springs, connectors and watch-industry parts, and Fisk names springs, optical frames and resistors. Matthey rates cold forming as excellent and hot forming as limited. The density is 8.7 g/cm3 and the electrical conductivity is 6 %IACS when annealed.
uses:
- where: Relay springs and glasses hinges
line: Matthey lists relay springs, hinges for glasses, connectors, watch-industry components and pressure membranes as typical uses. Fisk lists springs among its applications.
- where: Connectors, resistors and contacts
line: Fisk lists resistors and contacts; Matthey lists connectors and parts for precision and electronic instruments.
- where: Optical frames and parts
line: Fisk lists optical frames and parts first among its applications, and Matthey names optical instruments.
can_do:
- label: Spring
value: 680 MPa minimum
benchmark: ultimate_tensile_strength
line: Extra hard H200 strip has a minimum tensile strength of 680 MPa (Matthey). Round wire spring temper H08 is 105 ksi minimum (Fisk).
- label: Carry current
value: 6 %IACS
benchmark: electrical_conductivity
line: Electrical conductivity is 6 %IACS in Matthey's table and 6 %IACS annealed in Fisk's table.
- label: Carry heat
value: 32 W/(m·K)
benchmark: thermal_conductivity
line: Thermal conductivity is 32 W/m °K at 20 °C (Matthey).
- label: Weight
value: 8.7 g/cm3
benchmark: density
line: Density is 8.7 g/cm3 (Matthey). Fisk prints 0.316 lb/in3.
- label: Melting
value: 1060 to 1110 °C
benchmark: melting_point
line: The melting range is 1060 to 1110 °C (Matthey).
compare: The copper profile at /profiles/copper/ covers the pure metal. Within this profile, the two suppliers print strength in different units (MPa for strip, ksi for round wire), and the strip table gives 680 MPa minimum at its hardest temper while round wire reaches 111 ksi, so the two tables should not be compared number to number.
compare_rows:
- label: Density
benchmark: density
- label: Thermal conductivity
benchmark: thermal_conductivity
- label: Thermal expansion
benchmark: cte
handling:
- 'Specify the temper: strip runs from 370 MPa soft annealed to 680 MPa minimum extra hard (Matthey); round wire runs from 53.0 ksi annealed to 111 ksi hard (Fisk).'
- Anneal at 620 to 700 °C (Matthey) and stress-relieve at 300 to 350 °C after cold forming.
- Lead is an impurity limit only (0.03 % maximum by Matthey, 0.05 % by Fisk). Chips and dust should be handled as nickel-containing material, which is an inference from the nickel hazard statements.
good_for:
- Springs, relay parts and hinges where a silver colour and a spring temper are both needed.
- Connectors and precision optical or watch parts stamped, folded or bent from strip (Matthey).
- 'Brazed or soldered assemblies: Fisk rates soldering and brazing as excellent (5 of 5).'
watch_out:
- Machining is poor (Fisk 1 of 5, Matthey rather poor). Matthey recommends a leaded nickel silver for good machinability.
- 'The hard tempers have little elongation: 2 % in H185 strip.'
- Nickel content gives allergy and cancer hazard statements; handle chips and dust with that in mind.
- Oxidizing acids attack the alloy (Matthey poorly resistant). No corrosion rate is printed.
verdict: Nickel silver C75200 is a silvery copper-nickel-zinc alloy with good atmospheric and saline corrosion resistance, a 6 %IACS conductivity and spring-grade tempers up to 680 MPa minimum in strip. Its machinability is poor and its nickel content carries allergy and carcinogen hazard statements. The C75200 nominal (Cu 65, Ni 18, Zn 17) and the EN CW409J grade (Cu 60.0 to 63.0) are close but not the same, and the Matthey UNS number for CW409J (C76400) conflicts with ASTM B122. No yield strength, corrosion rate or space-environment result was found in the sources read.
recipe:
line: Nickel silver is a copper-nickel-zinc alloy with a single alpha phase (Matthey). Wikipedia gives the usual formulation as 60 % copper, 20 % nickel and 20 % zinc, and the C75200 nominal in ASTM B122 is 65 % copper, 18 % nickel and 17 % zinc.
parts:
- name: Copper
symbol: Cu
share: 63.0 to 66.5 wt% (C752, Fisk limits); 60.0 to 63.0 wt% (CW409J, Matthey limits); 65 wt% nominal (ASTM B122, C75200)
role: The matrix metal. It sets the colour base and most of the conductivity.
- name: Nickel
symbol: Ni
share: 16.5 to 19.5 wt% (Fisk limits); 17.0 to 19.0 wt% (Matthey limits); 18 wt% nominal (ASTM B122)
role: Gives the silvery, greyer colour (Matthey) and the corrosion resistance (Fisk and Matthey). It is also the source of the nickel hazard statements.
- name: Zinc
symbol: Zn
share: remainder (Matthey Zn balance; Fisk Zn remainder; ASTM B122 nominal 17 wt%)
role: The balance element that completes the alloy. The Fisk nominal print of zinc 35 does not match its limits and is not used.
- name: Lead
symbol: Pb
share: 0.03 wt% maximum (Matthey); 0.05 wt% maximum (Fisk)
role: Impurity limit only. Matthey says leaded grades such as CuNi12Zn25Pb1 are separate products for machinability.
- name: Iron
symbol: Fe
share: 0.30 wt% maximum (Matthey); 0.25 wt% maximum (Fisk)
role: Impurity limit printed by both datasheets.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| ASTM B122/B122M: copper-nickel-zinc alloy (nickel silver) plate, sheet, strip and rolled bar; UNS list and nominal composition table | standard | 1 value | ||
| Lamineries Matthey (Notz Metall), CuNi18Zn20 (Maillechort M18) technical datasheet: composition, physical properties, strip mechanical table | datasheet | 32 values | ||
| Fisk Alloy Wire: C752 Nickel Silver 18% alloy wire, chemical composition, physical properties, round wire and rolled flat temper tables, fabrication index | datasheet | 10 values | ||
| Wikipedia: Nickel silver (composition and history only) | web | 0 values | ||
| PubChem: Nickel, CID 935, Safety and Hazards, GHS classification (ECHA aggregated notifications) | database | 2 values | ||
| Mineral Commodity Summaries 2026: Copper | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026: Zinc | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026: Nickel | report | 2026 | 1 value |