CarTech EVANOHM® alloy S is a nickel-chromium resistance alloy developed to fill a specific need in ultra-precision resistance wire. It offers optimum stability and flexibility with regard to both size and required temperature coefficient of resistance (TCR).

The alloy's high resistivity and extremely low electro-motive force (EMF) versus copper are highly desired properties in precision resistance wire. It also possesses high tensile strength, high resistance to corrosion and is non-magnetic.

The temperature coefficient of resistance of this material is very closely controlled by the addition of aluminum, manganese and silicon combined with critical processing controls.

CarTech EVANOHM alloy S is supplied in the annealed and heat treated condition to ± 5 ppm in the temperature range of -67°F to 221°F (-55°C to 105°C). This results in very stable resistance.

Although EVANOHM alloy R is the only high-resistance, low-TCR alloy on which extensive stability tests have been conducted, EVANOHM alloy S is heat treated in the same manner and is believed to have equal stability because its properties are produced by the same short range ordering as CarTech EVANOHM alloy R.

Mechanical stresses, such as cold working, decrease resistivity and increase TCR in a positive direction. The magnitude of these changes is similar to CarTech EVANOHM alloy R, so that the same stress relieving procedures used in processing CarTech EVANOHM alloy R can and should be used.

Applications:
CarTech EVANOHM alloy S has been used in fine wire sizes for precision wound resistors over a temperature range from -67°F to 438°F (-55°C to 220°C).