Measurement study of residual stress on tungsten-rhenium thin film thermocouples by nanoindentation technology

In this paper, Nano-indentation technology is used to test the mechanical property of the tungsten-rhenium thin film, including hardness, elastic modulus and residual stress. The effects of different heat treatment temperature and different substrates on the hardness and elastic modulus of tungsten-rhenium films were studied. We research three substrates which are silicon carbide ceramic, aluminum oxide ceramic and zirconium oxide ceramic. Test results show that the tungsten-rhenium films on aluminum oxide ceramic shows the biggest values of elastic modulus and the smallest on silicon carbide ceramic. However, value of hardness is biggest on zirconium oxide ceramic and smallest on aluminum oxide ceramic. Besides, the heat treatment temperature has high influence on hardness and elastic modulus of tungsten-rhenium film. And under different substrates, the hardness and elastic modulus of film on zirconium oxide ceramic is the most sensitive to heat treatment temperature. By contrast, silicon carbide ceramic is the least.