Properties of Cold Sprayed Cermet Coatings and Effect of Compressive Strength of Cermet Powder Particle on Cold Spray Process

Cold spray process is expected to apply to many industrial fields because the process has the feature with a little heat influence to spray material and gets the uniform coating without oxide in the coating. Metal material powders are mainly used in the process but other powders such as cermet, ceramics are not so used. It is important to clarify the influence of properties of the powder on the process. Especially, little attention has been given to the compressive strength of powder. In this study influence of compressive strength of cermet powders are studied using compressive strength tester manufactured by Shimadzu Corporation type MCT-W500. Three Al2O3-Ni cermet powders with a different Ni content are sprayed on SUS304 stainless steel and also WC-Co powder is used for comparison with their powders. Al2O3-Ni and WC-Co cermet powders are agglomerated powders. Kinetic Metallization System manufactured by Inovati, USA is used as cold spray equipment. Cold spraying using Al2O3-Ni powders are carried out in various spray conditions. With decreasing in the gas pressure, the coating thickness become thicker but the coating flaked off from substrate and we cannot get good coatings in each spray conditions. The compressive strength of powder particle for using cold spray is lower than WC-Co powder for HVOF but behavior of Al2O3-Ni and WC-Co powder is different in compressive test and compressive strength of WC-Co is lower than Al2O3-Ni one. It is clarified that compressive strength of powder particle influenced on cold spray process