Manganina 38 is a copper-manganese-nickel alloy (CuMnNi alloy) for use at room temperature. The alloy is characterized by very low thermal electromotive force (emf) compared to copper.
Manganina 38 is typically used for the manufacturing of resistance standards, precision strip resistors, potentiometers, shunts and other electrical and electronic components.
The alloy's low emf vs. copper makes it ideal for use in electrical circuits, especially D.C., where a spurious thermal emf could cause malfunctioning of electronic equipment. Due to the low operating temperature, the temperature coefficient of resistance is controlled to be low over a range of 20 to 50°C (68 to 122°F).
Chemical composition
|
Ni % |
Mn % |
Cu % |
| Nominal composition |
4.0 |
10.0 |
Bal. |
Mechanical properties
| Yield Strength |
Tensile Strength |
Elongation |
Hardness |
| Rp0.2 |
Rm |
A |
|
| MPa |
MPa |
% |
Hv |
| 180 |
390 |
25 |
70–130 |
Physical properties
| Density g/cm3 |
8.4 |
| Electrical resistivity at 20°C Ω mm2/m |
0.38 |
| Temperature coefficient of resistance (20-50°C) (x 10-6/K) |
0 ± 15 |
Coefficient of thermal expansion
| Temperature °C |
Thermal Expansion x 10-6/K |
| 20 - 100 |
18 |
Thermal conductivity
| Temperature °C |
20 |
| W m-1 K-1 |
22 |
Specific heat capacity
| Temperature °C |
20 |
| kJ kg-1 K-1 |
0.410 |
| Melting point °C |
1020 |
| Max continuous operating temperature in air °C |
Room temperature |
| Magnetic properties |
The material is non-magnetic |
