Preparation and characteristics of BeNi film are described. Beryllium, often used in some alloys as an anti-oxidation material, seems to be also suitable as a constituent of film resistors. BeNi intermetallic compound film is found useful as a resistor because of its small temperature. coefficient of resistance of ± (1_??_5)×10
-5/deg and fair stability even at 300°C.
The film is made by vacuum deposition on glass, quartz, alumina and porcelain substrates in various thicknesses giving the resistance from 100 Ω/sq to 8 kΩ/sq. At about 100 Ω/sq, the power dissipated steadily can be as high as 2 watt/cm
2.
As to the effect of substrate on the film characteristics, when the substrate is of smooth surface such as glass or quartz, films of over a few hundred Å in thickness begin to crack all over the surface at 250°C, but when the substrate is of coarse surface such as alumina or porcelain, they remain unaltered even at 300°C.
To protect the film against atmospheric oxygen and water vapour, SiO, MgF
2 and epoxy resin are tried as coating, among which epoxy resin is found most effective.
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