Nicrosil is an austenitic nickel-chromium-silicon alloy (NiCrSi alloy) used for the positive leg of thermocouples type N. It offers higher thermoelectric stability in air above 1000°C (1830°F) and a better oxidation resistance in air than type E, J and K thermocouples.
Nicrosil alloy can not be exposed to reducing or alternatively oxidizing and reducing atmospheres or to vacuum. This thermocouple is the most recent one among the different types covered by the international standards.
Chemical composition
| Ni % | Cr % | Si % | |
|---|---|---|---|
| Nominal composition | Bal. | 14.2 | 1.5 |
Mechanical properties
| Wire size | Yield strength | Tensile strength | Elongation |
|---|---|---|---|
| Ø | Rp0.2 | Rm | A |
| mm | MPa | MPa | % |
| 2.0 | 310 | 800 | 35 |
Physical properties
| Density g/cm3 | 8.53 |
|---|---|
| Electrical resistivity at 20°C Ω mm2/m | 1.00 |
| Temperature coefficient of resistance between 20°C and 100°C x 10-6/K | 90 |
| Temperature °C | Thermal Expansion x 10-6/K |
|---|---|
| 20 - 100 | 17 |
| Temperature °C | 20 |
|---|---|
| W m-1 K-1 | 13 |
| Melting point °C | 1420 |
|---|---|
| Magnetic properties | The material is non-magnetic |
| Wire size Ø | 3.26 | 1.63 | 1.00 | 0.50 | 0.25 |
|---|---|---|---|---|---|
| Bare wire °C | 1100 | 1010 | 960 | 890 | 800 |
| Protected wire °C | 1250 | 1180 | 1110 | 1000 | 910 |
Note that the indicated temperatures should be considered as guide values
Thermoelectric properties
| Temp °C | mV |
|---|---|
| 100 | 2.774 |
| 200 | 5.913 |
| 300 | 9.341 |
| 400 | 12.974 |
| 500 | 16.748 |
| 600 | 20.613 |
| 700 | 24.527 |
| 800 | 28.455 |
| 900 | 32.371 |
| 1000 | 36.256 |
| 1100 | 40.087 |
| 1200 | 43.846 |
| 1300 | 47.513 |
ITS 90 - Reference junction 0°C
