Cold spray (CS) is a particle deposition method for fabricating thick films. Particles with supersonic speed accelerated by a relatively low-temperature gas impact a substrate, causing plastic deformation of the particles to fabricate a film. In this study, tungsten (W) films were fabricated from W particles, which are known as a hard metal and difficult to be plastically deform, by the low-pressure CS method. Three types of W particles with different particles size were used, and deposits were observed when deposited on an Al substrate with a working gas flow rate of 120-130 L/min. Among them, only the W film fabricated with particles of 2.00-3.99 μm in particles size showed an unevenness, therefore, the effect of crystallite size differences on the film fabrication was investigated using an X-ray diffraction. The results showed that the crystallite size of 2.00-3.99 μm particles was 71.3 nm, which was finer than that of the other particles. Furthermore, W films were fabricated on pure Ti, Cu, and SUS304 substrates, and it was found that films could be deposited on substrates harder than Al substrates.
SANADA et al. (Wed,) studied this question.