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.