Cold spray of SiC and Al2O3 with soft metal incorporation: A technical contribution

Al + SiC, Al + Al2O3 composites as well as pure Al, SiC, and Al2O3 coatings were prepared on Si substrates by the cold gas dynamic spray process (CGDS or cold spray). The powder composition of metal (Al) and ceramic (SiC, Al2O3) was varied into 1:1 and 10:1 wt.%, respectively. The propellant gas was air heated up to 330 deg C and the gas pressure was fixed at 0.7MPa. SiC and Al2O3 have been successfully sprayed producing coatings with more than 50 mum in thickness with the incorporation of Al as a binder. Also, hard ceramic particles showed peening effects on the coating surfaces. In the case of pure Al metal coating, there was no crater formation on hard Si substrates. However, when Al mixed with SiC and Al2O3, craters were observed and their quantities and sizes depended on the composition, aggregation and size of raw materials.