The Effect of the Substrate on the Microstructure and Tribological Properties of Cold Sprayed (CrC-25(Ni20Cr))-(Ni-graphite) Cermet Coatings.

In this work, the effect of the substrate, Al 7075 alloy and 1H18NT9 stainless steel, on the microstructure and tribological properties of cold sprayed (CrC-25(Ni20Cr))-(Ni-graphite) coatings was investigated. Both coatings were dense and did not reveal any discontinuities at the interfaces. They had similar CrC and graphite contents. Their microstructures showed a variety of grain sizes of the matrix phase between the inner part of the splat, showing large ones, and their boundaries, where elongated and nanostructured grains were formed during the deposition process. The coating deposited on the steel substrate revealed a slightly higher hardness and lower abrasive wear with the AlO loose abrasive particles. The force required to destroy the durability of the coating-steel substrate system in the three-point bending test was higher than those of the other ones. The cermet deposit cold sprayed on steel and examined at 25 °C under 10 N revealed the best wear resistance and the lowest friction coefficient.