Evanohm Ni-Cr-Al-Cu precision resistance alloy
Nickel-chromium-aluminium-copper alloy, Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 by mass (Goodfellow)
Also known as UNS N06720, EN 2.4872, Evanohm
Evanohm is a nickel-chromium-aluminium-copper precision resistance alloy.
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.
Stay at a fixed resistance
±10 ppm/°C
Carry current as a resistor
133 µΩ·cm
Stay solid when hot
1350 °C melting point
Low thermal EMF
1.0 µV/°C against copper
Recipe, share of the weight
- Ni 73.5%Nickel
- Cr 20%Chromium
- Al 2.5%Aluminium
- Cu 2%Copper
- Mn 1%Manganese
- Si 1%Silicon
Best for
Precision and strain-gauge resistors: a temperature coefficient of about ±10 ppm/°C with 133 µΩ·cm resistivity, and very low thermal EMF against copper (1.0 µV/°C)
Weakest at
Heat and load: Goodfellow gives 300 °C maximum use in air and no oxidation rate, and the annealed strip has a yield strength of only 300 MPa minimum
Risk at a glance
- People Low. Mixed classification
- If it fails Moderate. Resistance drift above the working temperature
- Corrosion Moderate. Moderate resistance to seawater.
Quick facts: Ni-Cr-Al-Cu precision resistance alloy
| Property | Value | Basis |
|---|---|---|
| Density | 8.1 g/cm³ | 2 sourced values across conditions |
| Yield strength | 300 to 1,620 MPa | 3 sourced values across conditions |
| Tensile strength | 650 to 1,655 MPa | 5 sourced values across conditions |
| Young's modulus | 221 GPa | 1 sourced value |
| Thermal conductivity | 14.6 W/(m·K) | 1 sourced value |
| Thermal expansion (CTE) | 11.7 to 13 ppm/K | 2 sourced values across conditions |
| Melting point | 1,340 to 1,390 °C | 2 sourced values across conditions |
| Specific heat | 435 J/(kg·K) | 1 sourced value |
| Electrical resistivity | 0.0000013 Ω·m | 2 sourced values across conditions |
| Maximum service temperature | 300 °C | 1 sourced value |
What is the density of Evanohm?
Evanohm has a density of 8.1 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 Evanohm?
Evanohm has a thermal conductivity of 14.6 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 Evanohm?
Evanohm has a coefficient of thermal expansion of 11.7 to 13 ppm/K. 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 melting point of Evanohm?
Evanohm has a melting point of 1,340 to 1,390 °C. 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 yield strength of Evanohm?
Evanohm has a yield strength of 300 to 1,620 MPa. The range covers 3 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 Evanohm?
Evanohm is also written as UNS N06720, EN 2.4872, Evanohm. Each code is printed in the source listed beside it in the designations table.
What is Evanohm used for?
Uses recorded in the sources include Strain gauges; Precision resistors; Precision current-sense resistors in measurement instruments.
Why it exists
Evanohm is a precision resistance alloy. It is nickel-chromium with aluminium and copper, and it was made to give a resistance that changes very little with temperature. Matthey and Hamilton give a temperature coefficient of about ±10 ppm/°C, with a resistivity of 133 µΩ·cm at room temperature (Hamilton) and a thermal EMF of 1.0 µV/°C against copper (Matthey). Those three figures make it a precision resistor alloy, not a heating alloy. Its weak points are the 300 °C maximum use temperature in air and the limited sources for stability at temperature.
Where it's used
Strain gauges and precision resistors
Matthey calls Evanohm the material of choice for strain gauges and electrical resistors. Goodfellow adds precision current-sense resistors in measurement instruments and stable resistance elements in aerospace-grade control systems.
Foil heaters
Hamilton lists foil heaters and airbag igniters among the uses of its Evanohm R strip and foil.
Recipe
Nickel-chromium-aluminium-copper alloy, Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 by mass (Goodfellow); Carpenter nominal for Evanohm R: Ni 73.50, Cr 20.00, Al 2.50, Cu 2.00, Mn 1.00, Si 1.00
Evanohm is a nickel-chromium alloy with aluminium and copper additions, plus small amounts of manganese and silicon. Carpenter's nominal analysis for Evanohm R is 73.50 % Ni, 20.00 % Cr, 2.50 % Al, 2.00 % Cu, 1.00 % Mn and 1.00 % Si. Matthey's composition table gives ranges for chromium, manganese, silicon and aluminium and maximum limits for carbon, sulfur and phosphorus, but it does not list copper. Goodfellow's simpler Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 analysis is for foil. The alloy is melted and conditioned by the producer and then rolled to strip or foil, with an annealing step at 400 to 600 °C (Matthey).
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Nickel Ni | 73.5% | The matrix of the alloy. Carpenter prints 73.50 % nominal; Goodfellow gives 75 % for its foil grade. |
| Chromium Cr | 20% | Forms the protective chromium oxide film and gives the alloy its oxidation and corrosion resistance. Matthey gives a range for chromium in its composition table. |
| Aluminium Al | 2.5% | Helps set the temperature coefficient of resistance and the resistivity response to heat treatment. Matthey gives a wider range for aluminium in its composition table. |
| Copper Cu | 2% | Included in the nominal analysis; Matthey's designation lists Cu 2 but its composition table does not give copper. |
| Manganese Mn | 1% | Nominal addition (Carpenter), with Matthey giving a range in its composition table. |
| Silicon Si | 1% | Nominal addition (Carpenter), with Matthey giving a range in its composition table. |
Weight shares are as printed in the sources.
What it can do
Stay at a fixed resistance
±10 ppm/°C
measured
Hamilton gives ±10 ppm/°C from -55 to 105 °C in heat-treated material. Matthey gives ±10 ppm/°C from -65 to 125 °C.
Carry current as a resistor
133 µΩ·cm
measured
Hamilton prints 133 µΩ·cm at room temperature. Goodfellow prints 134 µΩ·cm for the foil grade.
Stay solid when hot
1350 °C melting point
measured
Hamilton prints 1350 °C as the approximate melting point. Goodfellow prints a range of 1340 to 1390 °C.
Low thermal EMF
1.0 µV/°C against copper
measured
Matthey prints a thermal EMF of 1.0 µV/°C against pure copper from 0 to 100 °C, which matters for low-level measurements where a copper lead meets the resistor.
How it compares
Evanohm sits among the constant-resistance alloys. Wikipedia lists it with manganin and Cupron, and the trade-name table places it beside Karma. The profile gives Evanohm's own figures, not a ranking against those alloys, because Karma and the other manganin-type alloys were not read in this run.
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 | Ni-Cr-Al-Cu precision resistance alloy | NiCr 80/20 | KN | Ni-10Cr (Chromel-P) |
|---|---|---|---|---|
| Thermal behavior and safety | ||||
| Melting point, Evanohm R (approximate) | 1350 °C3 | 1400 °C | 1399 °C | 1430 °C |
| Melting range, Evanohm foilRange printed in a supplier product page | 1340 to 1390 °C | 1400 °C | 1399 °C | 1430 °C |
| Thermal conductivity at 20 °C, Evanohm RValue printed in a manufacturer datasheet | 14.6 W/(m·K)10 | 15 W/(m·K) | 0.297 W/(cm·°C) | 19.2 W/(m·K) |
| Specific heat capacity at 20 °C, Evanohm RValue printed in a manufacturer datasheet | 435 J/(kg·K)11 | 0.46 kJ/(kg·K) | 0.523 J/(g·K) | 0.448 kJ/(kg·K) |
| Thermal EMF against pure copper, 0 to 100 °CValue printed in a manufacturer datasheet | 1 µV/°C26 | no data | no data | no data |
| Physical and electrical | ||||
| Density, Evanohm R stripValue printed in a manufacturer datasheet | 8.1 g/cm³1 | 8.3 g/cm³ | 8.6 g/cm³ | 8.72 g/cm³ |
| Density, Evanohm foil (Goodfellow)Value printed in a supplier product page | 8.1 g/cm³2 | 8.3 g/cm³ | 8.6 g/cm³ | 8.72 g/cm³ |
| Electrical resistivity at room temperature, Evanohm RValue printed in a manufacturer product page | 133 µΩ·cm4 | 1.09 Ω mm2/m | 29.4 µΩ·cm | 0.706 Ω mm2/m |
| Electrical resistivity, Evanohm foilValue printed in a supplier product page | 134 µΩ·cm5 | 1.09 Ω mm2/m | 29.4 µΩ·cm | 0.706 Ω mm2/m |
| Hardness HV, annealed stripRange printed in a manufacturer datasheet | 160 to 280 HV25 | 180 HV | no data | 140 HV |
| Temperature behavior | ||||
| Temperature coefficient of resistance, heat-treated Evanohm RValue printed in a manufacturer product page | 10 ppm/°C6 | no data | 18.8 10-4 /°C | no data |
| Temperature coefficient of resistance, -65 to +125 °CValue printed in a manufacturer datasheet | 10 ppm/°C7 | no data | 18.8 10-4 /°C | no data |
| Temperature coefficient of resistance, -55 to +25 °CValue printed in a manufacturer datasheet | 5 ppm/°C8 | no data | 18.8 10-4 /°C | no data |
| Temperature coefficient of resistance, +25 to +125 °CValue printed in a manufacturer datasheet | -5 ppm/°C9 | no data | 18.8 10-4 /°C | no data |
| Standard temperature coefficient, Evanohm R (Carpenter)Value printed in a manufacturer product page | 10 ppm/°C27 | no data | 18.8 10-4 /°C | no data |
| Other measurements | ||||
| Coefficient of thermal expansion at 100 °C, Evanohm RValue printed in a manufacturer datasheet | 13 ppm/K12 | 14.1 ppm/K | 12 ppm/K | 17 ppm/K |
| Coefficient of thermal expansion, 20 to 100 °C, Evanohm foilValue printed in a supplier product page | 11.7 ppm/K13 | 14.1 ppm/K | 12 ppm/K | 17 ppm/K |
| Modulus of elasticity, Evanohm foilValue printed in a supplier product page | 221 GPa14 | no data | no data | 200 GPa |
| Tensile strength Rm, annealed stripRange printed in a manufacturer datasheet | 650 to 900 MPa15 | 810 MPa | 85 ksi | 95 ksi |
| Tensile strength Rm, hard stripMinimum printed in a manufacturer datasheet | > 1200 MPa16 | 810 MPa | 85 ksi | 95 ksi |
| Tensile strength, annealed (Hamilton)Value printed in a manufacturer product page | 1.2×10^5 psi17 | 810 MPa | 85 ksi | 95 ksi |
| Tensile strength, heat treated (Hamilton)Value printed in a manufacturer product page | 2.4×10^5 psi18 | 810 MPa | 85 ksi | 95 ksi |
| Tensile strength, Evanohm foilValue printed in a supplier product page | 1210 MPa19 | 810 MPa | 85 ksi | 95 ksi |
| Yield strength Rp0.2, annealed strip, minimumMinimum printed in a manufacturer datasheet | > 300 MPa20 | 420 MPa | 40 ksi | 45 ksi |
| Yield strength Rp0.2, hard strip, minimumMinimum printed in a manufacturer datasheet | > 900 MPa21 | 420 MPa | 40 ksi | 45 ksi |
| Yield strength Rp0.2 (0.2 % offset), heat treated (Hamilton)Value printed in a manufacturer product page | 2.35×10^5 psi22 | 420 MPa | 40 ksi | 45 ksi |
| Elongation A50, annealed strip, minimumMinimum printed in a manufacturer datasheet | > 30 %23 | 30 % | 35 % | 35 % |
| Elongation at break, Evanohm foilValue printed in a supplier product page | 33 %24 | 30 % | 35 % | 35 % |
| Maximum use temperature in air, Evanohm foilValue printed in a supplier product page | 300 °C | 1200 °C | no data | 900 °C |
Why choose it, and why not
Good for
- Precision resistors: about ±10 ppm/°C temperature coefficient with 133 µΩ·cm resistivity (Hamilton, Matthey).
- Strain gauges: named as the material of choice by Matthey, with good corrosion resistance.
- Low thermal EMF: 1.0 µV/°C against copper (Matthey).
Watch out for
- Maximum use temperature of 300 °C in air (Goodfellow), with no oxidation rate printed.
- Strength depends on temper: annealed strip has 650 to 900 MPa tensile strength, and hard strip has 1200 MPa minimum.
- The temperature coefficient is not constant: Matthey prints +5.0 ppm/°C from -55 to +25 °C and -5.0 ppm/°C from +25 to +125 °C.
- No corrosion rate, outgassing or radiation data were found.
Evanohm is a precision resistance alloy with a very low temperature coefficient, about ±10 ppm/°C, and a low thermal EMF against copper. Its resistivity of 133 µΩ·cm and its strip and foil forms suit precision resistors and strain gauges. Its limits are a 300 °C maximum use temperature in air and the lack of corrosion-rate and space-environment data in the sources read here.
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 | N06720 |
| EN | 2.4872 |
| Trade name | Evanohm |
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Density, Evanohm R strip | — | grade Evanohm R (Matthey strip datasheet)temperature not statedform strip | — |
| 2 | Density, Evanohm foil (Goodfellow) | — | grade Evanohm foil (Ni 75 / Cr 20 / Al 2.5 / Cu 2.5)temperature not statedform foil | — |
| 3 | Melting point, Evanohm R (approximate) | Value printed in a manufacturer product page, marked approximate | grade Evanohm Rpressure not stated | — |
| 4 | Electrical resistivity at room temperature, Evanohm R | — | grade Evanohm Rtemperature room temperature (R.T.)unit in source Microhm·cm | — |
| 5 | Electrical resistivity, Evanohm foil | — | grade Evanohm foiltemperature not statedunit in source µOhmcm | Goodfellow gives 134 and Hamilton gives 133 for the same nominal alloy; both are kept. |
| 6 | Temperature coefficient of resistance, heat-treated Evanohm R | — | grade Evanohm Rtemperature -55 to 105 °Ctemper heat treated (stabilising heat treatment of about 475 °C)sign printed as ± 10 | Non-canonical property name; the canonical property file has no temperature coefficient of resistance entry. |
| 7 | Temperature coefficient of resistance, -65 to +125 °C | — | grade Evanohm R (Matthey strip)temperature -65 to +125 °Csign printed as ± 10 | Non-canonical property name. Matthey prints the same ±10 ppm/°C in its main-features text. |
| 8 | Temperature coefficient of resistance, -55 to +25 °C | — | grade Evanohm R (Matthey strip)temperature -55 to +25 °Csign printed as + 5.0 | Non-canonical property name. The TCR is not constant over the range: Matthey prints +5.0 below 25 °C and -5.0 from 25 to 125 °C. |
| 9 | Temperature coefficient of resistance, +25 to +125 °C | — | grade Evanohm R (Matthey strip)temperature +25 to +125 °Csign printed as - 5.0 | Non-canonical property name. |
| 10 | Thermal conductivity at 20 °C, Evanohm R | — | grade Evanohm R (Matthey strip)temperature 20 °Cunit in source W/m °K | — |
| 11 | Specific heat capacity at 20 °C, Evanohm R | — | grade Evanohm R (Matthey strip)temperature 20 °Cunit in source J/(kg. K) | — |
| 12 | Coefficient of thermal expansion at 100 °C, Evanohm R | — | grade Evanohm R (Matthey strip)temperature 100 °Cunit in source 10⁻⁶/°C | Hamilton also prints 13 x 10-6 /°C for 20 to 100 °C, so the two sources agree. |
| 13 | Coefficient of thermal expansion, 20 to 100 °C, Evanohm foil | — | grade Evanohm foiltemperature 20 to 100 °Cunit in source x10⁻⁶ K⁻¹ | Goodfellow prints 11.7, while Matthey and Hamilton print 13 for a similar range. Both are kept; the difference is not explained by the sources. |
| 14 | Modulus of elasticity, Evanohm foil | — | grade Evanohm foiltemper not statedform foil | — |
| 15 | Tensile strength Rm, annealed strip | — | grade Evanohm R (Matthey strip)temper annealedform stripunit in source N/mm2 | — |
| 16 | Tensile strength Rm, hard strip | — | grade Evanohm R (Matthey strip)temper hardform stripunit in source N/mm2 | — |
| 17 | Tensile strength, annealed (Hamilton) | — | grade Evanohm Rtemper annealedform foil and strip | — |
| 18 | Tensile strength, heat treated (Hamilton) | — | grade Evanohm Rtemper heat treatedform foil and strip | — |
| 19 | Tensile strength, Evanohm foil | — | grade Evanohm foiltemper not statedform foil | — |
| 20 | Yield strength Rp0.2, annealed strip, minimum | — | grade Evanohm R (Matthey strip)temper annealedform stripunit in source N/mm2 | — |
| 21 | Yield strength Rp0.2, hard strip, minimum | — | grade Evanohm R (Matthey strip)temper hardform stripunit in source N/mm2 | — |
| 22 | Yield strength Rp0.2 (0.2 % offset), heat treated (Hamilton) | — | grade Evanohm Rtemper heat treatedform foil and strip | — |
| 23 | Elongation A50, annealed strip, minimum | — | grade Evanohm R (Matthey strip)temper annealedform strip | — |
| 24 | Elongation at break, Evanohm foil | — | grade Evanohm foiltemper not statedform foil | — |
| 25 | Hardness HV, annealed strip | — | grade Evanohm R (Matthey strip)temper annealedform strip | Non-canonical property name; hardness_vickers is not in the canonical property file. |
| 26 | Thermal EMF against pure copper, 0 to 100 °C | — | grade Evanohm R (Matthey strip)temperature 0 to 100 °C | Non-canonical property name. Hamilton prints <1.0 Millivolts/°C for the same figure, which is a different unit and is not used. |
| 27 | Standard temperature coefficient, Evanohm R (Carpenter) | — | grade Evanohm Rtemperature not statedsign printed as ±10 parts per million per °C | Non-canonical property name. Carpenter describes the standard grade; the heat-treated value is the Hamilton row above. |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Humid air | low | Excellent corrosion resistance in humid environments.1 |
| Mineral acids (nitric, phosphoric, sulfuric) | low | Good resistance to nitric, phosphoric and sulfuric acids.2 |
| Seawater | moderate | Moderate resistance to seawater.3 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Humid air | Matthey describes the alloy as having excellent corrosion resistance in humid environments. Carpenter describes high corrosion resistance. Neither gives a corrosion rate, test duration or humidity level. | environment humid airbasis manufacturer datasheet wording; no test data printed |
| 2 | Mineral acids (nitric, phosphoric, sulfuric) | Matthey lists good corrosion resistance to these three mineral acids. No concentration, temperature or attack rate is printed. | basis manufacturer datasheet wording; no concentration or temperature stated |
| 3 | Seawater | Matthey rates resistance to seawater as moderate, which is lower than its humid-air and mineral-acid rating. No attack rate, exposure time or temperature is printed. | basis manufacturer datasheet wording; no test data printed |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The alloy is mostly nickel and chromium. The sources do not classify the finished alloy, so the raw materials are the better guide.
- Nickel classification
- PubChem gives nickel H317, H351 and H372 with the signal word Danger, and most company reports carry hazard codes.
- Supplier classification
- The Airgas safety data sheet for nickel wire and rod is Not Classified under GHS. It is not a sheet for Evanohm itself.
- Carcinogenicity listing
- The same Airgas sheet notes IARC Group 2B for nickel, and the National Toxicology Program lists nickel as reasonably anticipated to be a human carcinogen.
If it fails
The sources give temperature limits and a drift threshold, but no failure rates.
- Overheating
- Goodfellow gives 300 °C as the maximum use temperature in air.
- Drift
- Matthey says resistivity hardly varies up to about 204 °C. The sources give no drift rate above that.
Handling and storage
- Heat treatment
- Anneal at 400 to 600 °C (Matthey). Hamilton uses a stabilising heat treatment of about 475 °C to set the TCR.
- Dust and fume
- Dust and fume from grinding or welding contain nickel and chromium compounds.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Resistance drift above the working temperaturemoderate severity | Use above about 204 °C in service, which is the temperature up to which Matthey says resistivity hardly variesMatthey gives no drift rate above 204 °C, so the stability of a resistor run hotter than this cannot be read from the sources. |
| Oxidation above the maximum use temperaturemoderate severity | Operation above 300 °C in air (Goodfellow maximum use temperature)Goodfellow gives 300 °C as the maximum use temperature in air but no oxidation rate, scale thickness or time to failure. |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Handling of dust and fume from grinding or welding | Nickel makes up most of the alloy, so dust or fume from grinding or welding contains nickel compounds. The Airgas sheet lists nickel as an IARC Group 2B possible carcinogen. |
Handling and storage
- Anneal between 400 and 600 °C (Matthey). Hamilton gives a stabilising heat treatment of about 475 °C to set the TCR of finished parts.
- Hamilton says the heat treatment virtually eliminates resistivity drift, and that a heat-treat curve is developed for each melt to regulate the TCR.
Supply and geography
How common the raw materials are and where they come from.
Nickel
- Top producers (2025)
- Indonesia 66.7%, Philippines 6.9%, Russia 5.1%, Canada 3.6%
- Recycling
- USGS: in 2025 nickel recovered from scrap accounted for approximately 60% of apparent consumption.
- Substitutes
- USGS: low-nickel, duplex or ultrahigh-chromium stainless steels replace austenitic grades in some uses; titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments.
Chromium
- Top producers (2025)
- South Africa 45.1%, Turkey 17.6%, Kazakhstan 13.7%
- Recycling
- USGS: recycled chromium in reported stainless-steel scrap receipts accounted for 21% of apparent consumption in 2025.
- Substitutes
- USGS: chromium has no substitute in stainless steel, the leading end use, or in superalloys.
Aluminium (primary smelter output)
- Top producers (2025)
- China 60.8%, India 5.7%, Russia 5.3%, Canada 4.5%
- Recycling
- USGS: in 2025 about 3.6 million tons of aluminum were recovered from purchased scrap in the United States (U.S. figure only).
- Substitutes
- USGS: composites can substitute for aluminum in aircraft fuselages and wings; glass, paper, plastics and steel can substitute in packaging.
Copper
- Top producers (2025)
- Chile 23%, Congo (Kinshasa) 13.9%, Peru 11.7%, China 7.8%
- Critical mineral lists
- US: listed
- Recycling
- USGS: old scrap converted to refined metal, alloys and other forms provided an estimated 160,000 tons of copper in 2025.
- Substitutes
- USGS: aluminum substitutes for copper in several uses, and optical fiber substitutes in telecommunications.
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.
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spore: profile
id: evanohm
spore_version: 0.2
family: resistance-and-thermocouple-alloys
name: Evanohm
abbreviation: Ni-Cr-Al-Cu precision resistance alloy
role: precision resistance alloy
category: metals
type: nickel-superalloys
summary: |
Evanohm is a nickel-chromium-aluminium-copper precision resistance alloy. Goodfellow gives its composition as Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 (UNS N06720, EN 2.4872), and the Carpenter nominal analysis for Evanohm R is 73.5 % Ni with 2.5 % Al, 2.0 % Cu, 1.0 % Mn and 1.0 % Si. Its electrical resistivity is 133 µΩ·cm at room temperature (Hamilton Precision Metals), its temperature coefficient of resistance is ±10 ppm/°C, and its thermal EMF against copper is 1.0 µV/°C (Matthey). It melts at about 1350 °C and is rated to 300 °C maximum use in air (Goodfellow). Evanohm is a Karma-type alloy: Wikipedia lists Evanohm and Karma side by side as constant-resistance trade names, but no Karma values were read for this profile.
best_for: 'Precision and strain-gauge resistors: a temperature coefficient of about ±10 ppm/°C with 133 µΩ·cm resistivity, and very low thermal EMF against copper (1.0 µV/°C)'
weakest_at: 'Heat and load: Goodfellow gives 300 °C maximum use in air and no oxidation rate, and the annealed strip has a yield strength of only 300 MPa minimum'
identity:
formula: 'Nickel-chromium-aluminium-copper alloy, Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 by mass (Goodfellow); Carpenter nominal for Evanohm R: Ni 73.50, Cr 20.00, Al 2.50, Cu 2.00, Mn 1.00, Si 1.00'
source: goodfellow-evanohm-foil
where: Properties common to all products list, Composition line (Ni 75/Cr20/Al 2.5/Cu 2.5); the Carpenter nominal analysis is in the Type Analysis table of carpenter-evanohm-r
designations:
- system: UNS
code: N06720
source: goodfellow-evanohm-foil
where: Properties common to all products list, UNS Number
- system: EN
code: '2.4872'
source: matthey-evanohm-r
where: Designation table, EN column
- system: Trade name
code: Evanohm
note: Trade names table lists Evanohm under the Carpenter Tech column
source: wikipedia-resistance-wire
where: Trade names table, row MWS-800
tags:
environments: []
stresses:
- extreme-heat
applications:
- electronics-and-chips
- thermal-control
- structures
properties:
- benchmark: density
label: Density, Evanohm R strip
value: 8.1
unit: g/cm3
scope: material
conditions:
grade: Evanohm R (Matthey strip datasheet)
temperature: not stated
form: strip
method: Value printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Physical properties table, Density row
- benchmark: density
label: Density, Evanohm foil (Goodfellow)
value: 8.1
unit: g/cm3
scope: material
conditions:
grade: Evanohm foil (Ni 75 / Cr 20 / Al 2.5 / Cu 2.5)
temperature: not stated
form: foil
method: Value printed in a supplier product page
status: ground
source: goodfellow-evanohm-foil
where: Physical Properties table, Density (g cm-3)
- benchmark: melting_point
label: Melting point, Evanohm R (approximate)
value: 1350
unit: °C
scope: material
conditions:
grade: Evanohm R
pressure: not stated
method: Value printed in a manufacturer product page, marked approximate
status: ground
source: hpm-evanohm-r
where: Physical Properties of Evanohm R Alloy, Melting Point (Approx.)
- benchmark: melting_point
label: Melting range, Evanohm foil
value: 1340
value_high: 1390
bound: range
unit: °C
scope: material
conditions:
grade: Evanohm foil
pressure: not stated
method: Range printed in a supplier product page
status: ground
source: goodfellow-evanohm-foil
where: Physical Properties table, Melting point row
- benchmark: electrical_resistivity
label: Electrical resistivity at room temperature, Evanohm R
value: 133
unit: µΩ·cm
scope: material
conditions:
grade: Evanohm R
temperature: room temperature (R.T.)
unit_in_source: Microhm·cm
method: Value printed in a manufacturer product page
status: ground
source: hpm-evanohm-r
where: Physical Properties of Evanohm R Alloy, Electrical Resistivity @ R.T.
- benchmark: electrical_resistivity
label: Electrical resistivity, Evanohm foil
value: 134
unit: µΩ·cm
scope: material
conditions:
grade: Evanohm foil
temperature: not stated
unit_in_source: µOhmcm
method: Value printed in a supplier product page
status: ground
note: Goodfellow gives 134 and Hamilton gives 133 for the same nominal alloy; both are kept.
source: goodfellow-evanohm-foil
where: Electrical Properties table, Electrical resistivity row
- benchmark: temperature_coefficient_of_resistance
label: Temperature coefficient of resistance, heat-treated Evanohm R
value: 10
unit: ppm/°C
scope: material
conditions:
grade: Evanohm R
temperature: '-55 to 105 °C'
temper: heat treated (stabilising heat treatment of about 475 °C)
sign: printed as ± 10
method: Value printed in a manufacturer product page
status: ground
note: Non-canonical property name; the canonical property file has no temperature coefficient of resistance entry.
source: hpm-evanohm-r
where: Physical Properties of Evanohm R Alloy, Temperature Coefficient of Resistivity (TCR), heat treated
- benchmark: temperature_coefficient_of_resistance
label: Temperature coefficient of resistance, -65 to +125 °C
value: 10
unit: ppm/°C
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temperature: '-65 to +125 °C'
sign: printed as ± 10
method: Value printed in a manufacturer datasheet
status: ground
note: Non-canonical property name. Matthey prints the same ±10 ppm/°C in its main-features text.
source: matthey-evanohm-r
where: Physical properties table, Temperature Coefficient of Resistance row, TCR -65 to +125 ºC
- benchmark: temperature_coefficient_of_resistance
label: Temperature coefficient of resistance, -55 to +25 °C
value: 5
unit: ppm/°C
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temperature: '-55 to +25 °C'
sign: printed as + 5.0
method: Value printed in a manufacturer datasheet
status: ground
note: 'Non-canonical property name. The TCR is not constant over the range: Matthey prints +5.0 below 25 °C and -5.0 from 25 to 125 °C.'
source: matthey-evanohm-r
where: Physical properties table, Temperature Coefficient of Resistance row, TCR -55 to +25 ºC
- benchmark: temperature_coefficient_of_resistance
label: Temperature coefficient of resistance, +25 to +125 °C
value: -5
unit: ppm/°C
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temperature: +25 to +125 °C
sign: printed as - 5.0
method: Value printed in a manufacturer datasheet
status: ground
note: Non-canonical property name.
source: matthey-evanohm-r
where: Physical properties table, Temperature Coefficient of Resistance row, TCR +25 to +125 ºC
- benchmark: thermal_conductivity
label: Thermal conductivity at 20 °C, Evanohm R
value: 14.6
unit: W/(m·K)
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temperature: 20 °C
unit_in_source: W/m °K
method: Value printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Physical properties table, Thermal conductivity at 20 ºC
- benchmark: specific_heat
label: Specific heat capacity at 20 °C, Evanohm R
value: 435
unit: J/(kg·K)
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temperature: 20 °C
unit_in_source: J/(kg. K)
method: Value printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Physical properties table, Specific heat at 20 ºC
- benchmark: cte
label: Coefficient of thermal expansion at 100 °C, Evanohm R
value: 13
unit: ppm/K
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temperature: 100 °C
unit_in_source: 10⁻⁶/°C
method: Value printed in a manufacturer datasheet
status: ground
note: Hamilton also prints 13 x 10-6 /°C for 20 to 100 °C, so the two sources agree.
source: matthey-evanohm-r
where: Physical properties table, Linear dilatation coefficient at 100 ºC
- benchmark: cte
label: Coefficient of thermal expansion, 20 to 100 °C, Evanohm foil
value: 11.7
unit: ppm/K
scope: material
conditions:
grade: Evanohm foil
temperature: 20 to 100 °C
unit_in_source: x10⁻⁶ K⁻¹
method: Value printed in a supplier product page
status: ground
note: Goodfellow prints 11.7, while Matthey and Hamilton print 13 for a similar range. Both are kept; the difference is not explained by the sources.
source: goodfellow-evanohm-foil
where: Physical Properties table, Coefficient of thermal expansion row, 20-100°C
- benchmark: elastic_modulus
label: Modulus of elasticity, Evanohm foil
value: 221
unit: GPa
scope: material
conditions:
grade: Evanohm foil
temper: not stated
form: foil
method: Value printed in a supplier product page
status: ground
source: goodfellow-evanohm-foil
where: Mechanical Properties table, Modulus of elasticity row
- benchmark: ultimate_tensile_strength
label: Tensile strength Rm, annealed strip
value: 650
value_high: 900
bound: range
unit: MPa
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temper: annealed
form: strip
unit_in_source: N/mm2
method: Range printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Mechanical properties of strips, annealed row, Rm
- benchmark: ultimate_tensile_strength
label: Tensile strength Rm, hard strip
value: 1200
bound: lower
unit: MPa
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temper: hard
form: strip
unit_in_source: N/mm2
method: Minimum printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Mechanical properties of strips, hard row, Rm min
- benchmark: ultimate_tensile_strength
label: Tensile strength, annealed (Hamilton)
value: 120000
unit: psi
scope: material
conditions:
grade: Evanohm R
temper: annealed
form: foil and strip
method: Value printed in a manufacturer product page
status: ground
source: hpm-evanohm-r
where: Typical Mechanical Properties of Evanohm R Alloy, Ultimate Tensile Strength, ANNEALED column
- benchmark: ultimate_tensile_strength
label: Tensile strength, heat treated (Hamilton)
value: 240000
unit: psi
scope: material
conditions:
grade: Evanohm R
temper: heat treated
form: foil and strip
method: Value printed in a manufacturer product page
status: ground
source: hpm-evanohm-r
where: Typical Mechanical Properties of Evanohm R Alloy, Ultimate Tensile Strength, HEAT TREATED column
- benchmark: ultimate_tensile_strength
label: Tensile strength, Evanohm foil
value: 1210
unit: MPa
scope: material
conditions:
grade: Evanohm foil
temper: not stated
form: foil
method: Value printed in a supplier product page
status: ground
source: goodfellow-evanohm-foil
where: Mechanical Properties table, Tensile strength row
- benchmark: yield_strength
label: Yield strength Rp0.2, annealed strip, minimum
value: 300
bound: lower
unit: MPa
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temper: annealed
form: strip
unit_in_source: N/mm2
method: Minimum printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Mechanical properties of strips, annealed row, Rp0.2 min
- benchmark: yield_strength
label: Yield strength Rp0.2, hard strip, minimum
value: 900
bound: lower
unit: MPa
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temper: hard
form: strip
unit_in_source: N/mm2
method: Minimum printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Mechanical properties of strips, hard row, Rp0.2 min
- benchmark: yield_strength
label: Yield strength Rp0.2 (0.2 % offset), heat treated (Hamilton)
value: 235000
unit: psi
scope: material
conditions:
grade: Evanohm R
temper: heat treated
form: foil and strip
method: Value printed in a manufacturer product page
status: ground
source: hpm-evanohm-r
where: Typical Mechanical Properties of Evanohm R Alloy, Yield Strength (0.2% Offset), HEAT TREATED column
- benchmark: elongation
label: Elongation A50, annealed strip, minimum
value: 30
bound: lower
unit: '%'
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temper: annealed
form: strip
method: Minimum printed in a manufacturer datasheet
status: ground
source: matthey-evanohm-r
where: Mechanical properties of strips, annealed row, A50mm min
- benchmark: elongation
label: Elongation at break, Evanohm foil
value: 33
unit: '%'
scope: material
conditions:
grade: Evanohm foil
temper: not stated
form: foil
method: Value printed in a supplier product page
status: ground
source: goodfellow-evanohm-foil
where: Mechanical Properties table, Elongation at break row
- benchmark: hardness_vickers
label: Hardness HV, annealed strip
value: 160
value_high: 280
bound: range
unit: HV
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temper: annealed
form: strip
method: Range printed in a manufacturer datasheet
status: ground
note: Non-canonical property name; hardness_vickers is not in the canonical property file.
source: matthey-evanohm-r
where: Mechanical properties of strips, annealed row, Hardness HV
- benchmark: thermal_emf_vs_copper
label: Thermal EMF against pure copper, 0 to 100 °C
value: 1
unit: µV/°C
scope: material
conditions:
grade: Evanohm R (Matthey strip)
temperature: 0 to 100 °C
method: Value printed in a manufacturer datasheet
status: ground
note: Non-canonical property name. Hamilton prints <1.0 Millivolts/°C for the same figure, which is a different unit and is not used.
source: matthey-evanohm-r
where: Physical properties table, Thermal EMF versus pure copper from 0 to 100 ºC
- benchmark: max_service_temp
label: Maximum use temperature in air, Evanohm foil
value: 300
unit: °C
scope: material
conditions:
grade: Evanohm foil
environment: air
method: Value printed in a supplier product page
status: ground
source: goodfellow-evanohm-foil
where: Thermal Properties table, Maximum use temperature in air row
- benchmark: temperature_coefficient_of_resistance
label: Standard temperature coefficient, Evanohm R (Carpenter)
value: 10
unit: ppm/°C
scope: material
conditions:
grade: Evanohm R
temperature: not stated
sign: printed as ±10 parts per million per °C
method: Value printed in a manufacturer product page
status: ground
note: Non-canonical property name. Carpenter describes the standard grade; the heat-treated value is the Hamilton row above.
source: carpenter-evanohm-r
where: Product description paragraph, standard temperature coefficient
corrosion:
- environment: Humid air
headline: Excellent corrosion resistance in humid environments.
effect: Matthey describes the alloy as having excellent corrosion resistance in humid environments. Carpenter describes high corrosion resistance. Neither gives a corrosion rate, test duration or humidity level.
rating: low
conditions:
environment: humid air
basis: manufacturer datasheet wording; no test data printed
source: matthey-evanohm-r
where: Main technical properties and features, second paragraph
- environment: Mineral acids (nitric, phosphoric, sulfuric)
headline: Good resistance to nitric, phosphoric and sulfuric acids.
effect: Matthey lists good corrosion resistance to these three mineral acids. No concentration, temperature or attack rate is printed.
rating: low
conditions:
basis: manufacturer datasheet wording; no concentration or temperature stated
source: matthey-evanohm-r
where: Main technical properties and features, second paragraph
- environment: Seawater
headline: Moderate resistance to seawater.
effect: Matthey rates resistance to seawater as moderate, which is lower than its humid-air and mineral-acid rating. No attack rate, exposure time or temperature is printed.
rating: moderate
conditions:
basis: manufacturer datasheet wording; no test data printed
source: matthey-evanohm-r
where: Main technical properties and features, second paragraph
risks:
hazards:
- text: PubChem gives nickel (CID 935) the GHS statements H317 (may cause an allergic skin reaction), H351 (suspected of causing cancer) and H372 (causes damage to organs through prolonged or repeated exposure), with signal word Danger. The classification is for nickel, the main element in the alloy, not for the finished alloy.
ghs: []
source: pubchem-nickel
where: Safety and Hazards, GHS Classification, Hazard Statements
- text: PubChem notes that this chemical does not meet GHS hazard criteria in 5 of 4778 company reports (0.1 %), so most nickel reports carry hazard codes.
ghs: []
source: pubchem-nickel
where: Safety and Hazards, ECHA C&L Notifications Summary
- text: The Airgas safety data sheet for nickel wire and rod classifies the product as Not Classified under GHS, with no hazard symbol or signal word. The sheet covers nickel wire and rod, not Evanohm.
ghs: []
source: airgas-nickel-sds
where: Section 2, GHS Hazard Classification line
- text: The same Airgas sheet notes that IARC classifies nickel as a possible carcinogen to humans (Group 2B), and that the National Toxicology Program lists nickel as reasonably anticipated to be a human carcinogen.
ghs: []
source: airgas-nickel-sds
where: Health hazard section, Carcinogenicity text
failure_risks:
- mode: Resistance drift above the working temperature
trigger: Use above about 204 °C in service, which is the temperature up to which Matthey says resistivity hardly varies
consequence: Matthey gives no drift rate above 204 °C, so the stability of a resistor run hotter than this cannot be read from the sources.
severity: moderate
source: matthey-evanohm-r
where: Main technical properties and features, first paragraph (resistivity hardly varies up to 204 ºC)
- mode: Oxidation above the maximum use temperature
trigger: Operation above 300 °C in air (Goodfellow maximum use temperature)
consequence: Goodfellow gives 300 °C as the maximum use temperature in air but no oxidation rate, scale thickness or time to failure.
severity: moderate
source: goodfellow-evanohm-foil
where: Thermal Properties table, Maximum use temperature in air
side_effects:
- text: Nickel makes up most of the alloy, so dust or fume from grinding or welding contains nickel compounds. The Airgas sheet lists nickel as an IARC Group 2B possible carcinogen.
affects: Handling of dust and fume from grinding or welding
source: airgas-nickel-sds
where: Health hazard section, Carcinogenicity text
handling:
- text: Anneal between 400 and 600 °C (Matthey). Hamilton gives a stabilising heat treatment of about 475 °C to set the TCR of finished parts.
source: matthey-evanohm-r
where: Heat treatment section
- text: Hamilton says the heat treatment virtually eliminates resistivity drift, and that a heat-treat curve is developed for each melt to regulate the TCR.
source: hpm-evanohm-r
where: Evanohm R Strip and Foil description paragraph
mitigations: []
uses:
- application: structures
device: Strain gauges
example: Matthey says Evanohm is the material of choice for strain gauges and electrical resistors, because of its combination of low TCR and corrosion resistance. Hamilton lists strain gauges as a main use.
source: matthey-evanohm-r
where: Typical uses section
- application: electronics-and-chips
device: Precision resistors
example: Matthey lists electrical resistors as a typical use. Carpenter lists the alloy for precision use, with the standard ±10 ppm/°C temperature coefficient.
source: matthey-evanohm-r
where: Typical uses section
- application: electronics-and-chips
device: Precision current-sense resistors in measurement instruments
example: Goodfellow lists precision current-sense resistors in measurement instrumentation, and stable resistance elements in aerospace-grade control systems.
source: goodfellow-evanohm-foil
where: Product description paragraph, specific uses sentence
- application: thermal-control
device: Foil heaters
example: Hamilton lists foil heaters as a use for Evanohm R strip and foil. Hamilton gives the alloy's supplied form as foil and strip down to 0.000100 in thick.
source: hpm-evanohm-r
where: Evanohm R Strip and Foil description paragraph; Sizes section
supply:
- subject: Nickel
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
recycling: 'USGS: in 2025 nickel recovered from scrap accounted for approximately 60% of apparent consumption.'
substitutes:
- 'USGS: low-nickel, duplex or ultrahigh-chromium stainless steels replace austenitic grades in some uses; 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 column (world total 3,900,000 t; shares calculated by Space Mushroom against that printed total); Recycling; Substitutes
- subject: Chromium
producers:
- country: South Africa
share_percent: 45.1
year: 2025
- country: Turkey
share_percent: 17.6
year: 2025
- country: Kazakhstan
share_percent: 13.7
year: 2025
recycling: 'USGS: recycled chromium in reported stainless-steel scrap receipts accounted for 21% of apparent consumption in 2025.'
substitutes:
- 'USGS: chromium has no substitute in stainless steel, the leading end use, or in superalloys.'
source: usgs-mcs2026-chromium
where: World Mine Production and Reserves table, 2025e column (world total 51,000 thousand t; shares calculated by Space Mushroom; Kazakhstan value is estimated by USGS); Recycling; Substitutes
- subject: Aluminium (primary smelter output)
producers:
- country: China
share_percent: 60.8
year: 2025
- country: India
share_percent: 5.7
year: 2025
- country: Russia
share_percent: 5.3
year: 2025
- country: Canada
share_percent: 4.5
year: 2025
recycling: 'USGS: in 2025 about 3.6 million tons of aluminum were recovered from purchased scrap in the United States (U.S. figure only).'
substitutes:
- 'USGS: composites can substitute for aluminum in aircraft fuselages and wings; glass, paper, plastics and steel can substitute in packaging.'
source: usgs-mcs2026-aluminum
where: World Smelter Production table, 2025e column (world total 74,000 thousand t; shares calculated by Space Mushroom); Recycling; Substitutes. Aluminum is a 2.5 % constituent of this alloy.
- subject: Copper
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
recycling: 'USGS: old scrap converted to refined metal, alloys and other forms provided an estimated 160,000 tons of copper in 2025.'
substitutes:
- 'USGS: aluminum substitutes for copper in several uses, and optical fiber substitutes in telecommunications.'
critical_lists:
- list: USGS 2025 List of Critical Minerals (copper added in the final 2025 list)
listed: true
source: usgs-mcs2026-copper
where: World Mine and Refinery Production table, Mine production 2025e column (world total 23,000 thousand t; shares calculated by Space Mushroom); Final 2025 List of Critical Minerals paragraph; Substitutes. Copper is a 2.0 to 2.5 % constituent of this alloy.
documents:
- title: 'Goodfellow: Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy product page'
type: datasheet
url: https://www.goodfellow.com/usa/evanohm-foil-group
year: 2025
- title: 'Lamineries Matthey: Evanohm datasheet (EvanohmR_v24E)'
type: datasheet
url: https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf
year: 2024
- title: 'Hamilton Precision Metals: Evanohm R Strip and Foil product page'
type: datasheet
url: https://www.hpmetals.com/products/materials/evanohm-r-strip-foil
- title: 'Carpenter Technology: Evanohm R specialty alloy page'
type: datasheet
url: https://www.carpentertechnology.com/alloy-finder/Evanohm-R
- title: 'Wikipedia: Resistance wire (trade names table)'
type: database
url: https://en.wikipedia.org/wiki/Resistance_wire
- title: 'USGS Mineral Commodity Summaries 2026: Nickel'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Chromium'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Aluminum'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Copper'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
year: 2026
- title: 'PubChem: Nickel (CID 935), GHS classification summary'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/935
year: 2026
- title: Airgas Nickel Wire and Rod safety data sheet, SDS 011-Ni Wire and Rod
type: sds
url: https://www.airgas.com/msds/005727.pdf
gaps:
- 'Evanohm S grade not read: the CarTech Evanohm S and R datasheet pages returned no readable content in this run, and the ASM Alloy Digest entries are paywalled.'
- Karma values not read. The only Karma source was an ASM Alloy Digest entry that is paywalled. Karma appears in the Wikipedia trade-names table under Driver-Harris, so it is a related alloy and not an alias; no Karma property is recorded here.
- Matthey's composition table omits copper, but its designation (NiCr20Al2.5Cu2Mn1Si1) includes Cu 2. Copper is taken from Goodfellow and Carpenter only.
- Matthey's designation table lists UNS N10276 against this grade. Hamilton prints N10276 as its Hastelloy C-276 strip, so the code is not used here.
- Matthey's resistivity row prints 133 with the unit cut off in the PDF text, so the value is taken from Hamilton (133 µΩ·cm) and Goodfellow (134 µΩ·cm) instead.
- Temperature coefficient of resistance and thermal EMF against copper are not canonical property names (temperature_coefficient_of_resistance, thermal_emf_vs_copper). Hardness_vickers is also non-canonical, as in the nichrome profile.
- 'Coefficient of thermal expansion disagrees between sources: Matthey and Hamilton print 13 x 10-6/°C, Goodfellow prints 11.7 x 10-6/K. All three are kept with their sources.'
- Carpenter prints a stability figure of 1 to 15 microhms per year. The unit and basis are not clear from the page, so it is not recorded.
- No corrosion rate, oxidation rate, outgassing, atomic-oxygen or radiation data were found for Evanohm. No NASA or ESA flight heritage was found in a search, so the profile has no space application source.
- Atomic weights of nickel, chromium, aluminium and copper were not read from a fetched page, so the recipe parts carry shares only.
- 'Critical-mineral list status for nickel, chromium and aluminium: the 2026 USGS nickel, chromium and aluminum summaries read in this run do not name a critical-minerals list, so no list entry is recorded for them. EU critical raw materials list not read.'
- No CAS number was read for this alloy.
- Hazard data are for nickel (PubChem) and for a nickel wire and rod (Airgas). No SDS for Evanohm itself was read.
sources:
matthey-evanohm-r:
title: Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E)
url: https://matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/EvanohmR_v24E.pdf
year: 2024
kind: datasheet
license: Manufacturer datasheet (cited, not reproduced)
goodfellow-evanohm-foil:
title: Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow)
url: https://www.goodfellow.com/usa/evanohm-foil-group
kind: web
license: Supplier product page (cited, not reproduced)
hpm-evanohm-r:
title: Evanohm R Strip and Foil (Hamilton Precision Metals)
url: https://www.hpmetals.com/products/materials/evanohm-r-strip-foil
kind: web
license: Supplier product page (cited, not reproduced)
carpenter-evanohm-r:
title: Evanohm R, specialty alloys (Carpenter Technology)
url: https://www.carpentertechnology.com/alloy-finder/Evanohm-R
kind: web
license: Manufacturer product page (cited, not reproduced)
wikipedia-resistance-wire:
title: Resistance wire (Wikipedia)
url: https://en.wikipedia.org/wiki/Resistance_wire
kind: web
license: CC BY-SA 4.0 (cited, not reproduced)
usgs-mcs2026-nickel:
title: Mineral Commodity Summaries 2026, Nickel
id: USGS MCS 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-mcs2026-chromium:
title: Mineral Commodity Summaries 2026, Chromium
id: USGS MCS 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-mcs2026-aluminum:
title: Mineral Commodity Summaries 2026, Aluminum
id: USGS MCS 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-aluminum.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-mcs2026-copper:
title: Mineral Commodity Summaries 2026, Copper
id: USGS MCS 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf
year: 2026
kind: report
license: public domain (USGS)
pubchem-nickel:
title: PubChem compound record, Nickel (CID 935)
id: CID 935
url: https://pubchem.ncbi.nlm.nih.gov/compound/935
year: 2026
kind: database
license: public domain (NCBI)
airgas-nickel-sds:
title: Safety Data Sheet, Nickel Wire and Rod, SDS 011-Ni Wire and Rod (Airgas)
url: https://www.airgas.com/msds/005727.pdf
kind: datasheet
license: Supplier safety data sheet (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
status: draft
method: assistant
checked_values: 29
unreachable: 3
caveats: 4
note: 'Values read by an AI assistant on 2026-10-26 from the pages named in each entry. Unreachable in this run: CarTech Evanohm S and R datasheet pages (no readable content), and the ASM Alloy Digest entries for Evanohm and Karma (paywalled). Caveats: strength values are for strip and foil of different tempers, not one temper; CTE differs between Goodfellow (11.7) and Matthey and Hamilton (13); the Hamilton thermal EMF is printed in mV and is not used; the supply shares are calculated from printed world totals.'
story:
recipe:
line: Evanohm is a nickel-chromium alloy with aluminium and copper additions, plus small amounts of manganese and silicon. Carpenter's nominal analysis for Evanohm R is 73.50 % Ni, 20.00 % Cr, 2.50 % Al, 2.00 % Cu, 1.00 % Mn and 1.00 % Si. Matthey's composition table gives ranges for chromium, manganese, silicon and aluminium and maximum limits for carbon, sulfur and phosphorus, but it does not list copper. Goodfellow's simpler Ni 75 / Cr 20 / Al 2.5 / Cu 2.5 analysis is for foil. The alloy is melted and conditioned by the producer and then rolled to strip or foil, with an annealing step at 400 to 600 °C (Matthey).
parts:
- name: Nickel
symbol: Ni
share_percent: 73.5
role: The matrix of the alloy. Carpenter prints 73.50 % nominal; Goodfellow gives 75 % for its foil grade.
- name: Chromium
symbol: Cr
share_percent: 20
role: Forms the protective chromium oxide film and gives the alloy its oxidation and corrosion resistance. Matthey gives a range for chromium in its composition table.
- name: Aluminium
symbol: Al
share_percent: 2.5
role: Helps set the temperature coefficient of resistance and the resistivity response to heat treatment. Matthey gives a wider range for aluminium in its composition table.
- name: Copper
symbol: Cu
share_percent: 2
role: Included in the nominal analysis; Matthey's designation lists Cu 2 but its composition table does not give copper.
- name: Manganese
symbol: Mn
share_percent: 1
role: Nominal addition (Carpenter), with Matthey giving a range in its composition table.
- name: Silicon
symbol: Si
share_percent: 1
role: Nominal addition (Carpenter), with Matthey giving a range in its composition table.
risk_groups:
- title: For people
lead: The alloy is mostly nickel and chromium. The sources do not classify the finished alloy, so the raw materials are the better guide.
level: 1
verdict: Mixed classification
points:
- label: Nickel classification
line: PubChem gives nickel H317, H351 and H372 with the signal word Danger, and most company reports carry hazard codes.
- label: Supplier classification
line: The Airgas safety data sheet for nickel wire and rod is Not Classified under GHS. It is not a sheet for Evanohm itself.
- label: Carcinogenicity listing
line: The same Airgas sheet notes IARC Group 2B for nickel, and the National Toxicology Program lists nickel as reasonably anticipated to be a human carcinogen.
- title: If it fails
lead: The sources give temperature limits and a drift threshold, but no failure rates.
points:
- label: Overheating
line: Goodfellow gives 300 °C as the maximum use temperature in air.
- label: Drift
line: Matthey says resistivity hardly varies up to about 204 °C. The sources give no drift rate above that.
- title: Handling and storage
points:
- label: Heat treatment
line: Anneal at 400 to 600 °C (Matthey). Hamilton uses a stabilising heat treatment of about 475 °C to set the TCR.
- label: Dust and fume
line: Dust and fume from grinding or welding contain nickel and chromium compounds.
why: Evanohm is a precision resistance alloy. It is nickel-chromium with aluminium and copper, and it was made to give a resistance that changes very little with temperature. Matthey and Hamilton give a temperature coefficient of about ±10 ppm/°C, with a resistivity of 133 µΩ·cm at room temperature (Hamilton) and a thermal EMF of 1.0 µV/°C against copper (Matthey). Those three figures make it a precision resistor alloy, not a heating alloy. Its weak points are the 300 °C maximum use temperature in air and the limited sources for stability at temperature.
uses:
- where: Strain gauges and precision resistors
line: Matthey calls Evanohm the material of choice for strain gauges and electrical resistors. Goodfellow adds precision current-sense resistors in measurement instruments and stable resistance elements in aerospace-grade control systems.
- where: Foil heaters
line: Hamilton lists foil heaters and airbag igniters among the uses of its Evanohm R strip and foil.
can_do:
- label: Stay at a fixed resistance
value: ±10 ppm/°C
benchmark: temperature_coefficient_of_resistance
line: Hamilton gives ±10 ppm/°C from -55 to 105 °C in heat-treated material. Matthey gives ±10 ppm/°C from -65 to 125 °C.
- label: Carry current as a resistor
value: 133 µΩ·cm
benchmark: electrical_resistivity
line: Hamilton prints 133 µΩ·cm at room temperature. Goodfellow prints 134 µΩ·cm for the foil grade.
- label: Stay solid when hot
value: 1350 °C melting point
benchmark: melting_point
line: Hamilton prints 1350 °C as the approximate melting point. Goodfellow prints a range of 1340 to 1390 °C.
- label: Low thermal EMF
value: 1.0 µV/°C against copper
benchmark: thermal_emf_vs_copper
line: Matthey prints a thermal EMF of 1.0 µV/°C against pure copper from 0 to 100 °C, which matters for low-level measurements where a copper lead meets the resistor.
compare: Evanohm sits among the constant-resistance alloys. Wikipedia lists it with manganin and Cupron, and the trade-name table places it beside Karma. The profile gives Evanohm's own figures, not a ranking against those alloys, because Karma and the other manganin-type alloys were not read in this run.
compare_rows:
- label: Electrical resistivity
benchmark: electrical_resistivity
- label: Temperature coefficient
benchmark: temperature_coefficient_of_resistance
- label: Maximum use temperature
benchmark: max_service_temp
handling:
- Keep continuous service at or below 300 °C in air (Goodfellow).
- Anneal at 400 to 600 °C, and use the stabilising heat treatment of about 475 °C to set the TCR (Matthey and Hamilton).
- Treat dust and fume from grinding or welding as containing nickel and chromium compounds (Airgas).
good_for:
- 'Precision resistors: about ±10 ppm/°C temperature coefficient with 133 µΩ·cm resistivity (Hamilton, Matthey).'
- 'Strain gauges: named as the material of choice by Matthey, with good corrosion resistance.'
- 'Low thermal EMF: 1.0 µV/°C against copper (Matthey).'
watch_out:
- Maximum use temperature of 300 °C in air (Goodfellow), with no oxidation rate printed.
- 'Strength depends on temper: annealed strip has 650 to 900 MPa tensile strength, and hard strip has 1200 MPa minimum.'
- 'The temperature coefficient is not constant: Matthey prints +5.0 ppm/°C from -55 to +25 °C and -5.0 ppm/°C from +25 to +125 °C.'
- No corrosion rate, outgassing or radiation data were found.
verdict: Evanohm is a precision resistance alloy with a very low temperature coefficient, about ±10 ppm/°C, and a low thermal EMF against copper. Its resistivity of 133 µΩ·cm and its strip and foil forms suit precision resistors and strain gauges. Its limits are a 300 °C maximum use temperature in air and the lack of corrosion-rate and space-environment data in the sources read here.
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 |
|---|---|---|---|---|
| Evanohm datasheet (Lamineries Matthey, EvanohmR_v24E) | datasheet | 2024 | 21 values | |
| Evanohm Foil/Sheet, Ni75-Cr20-Al2.5-Cu2.5 alloy (Goodfellow) | web | 11 values | ||
| Evanohm R Strip and Foil (Hamilton Precision Metals) | web | 8 values | ||
| Evanohm R, specialty alloys (Carpenter Technology) | web | 1 value | ||
| Resistance wire (Wikipedia) | web | 0 values | ||
| Mineral Commodity Summaries 2026, Nickel | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026, Chromium | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026, Aluminum | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026, Copper | report | 2026 | 1 value | |
| PubChem compound record, Nickel (CID 935) | database | 2026 | 2 values | |
| Safety Data Sheet, Nickel Wire and Rod, SDS 011-Ni Wire and Rod (Airgas) | datasheet | 3 values |