Cold Spray Multilayer Composite Coatings for Iron and Steel Castings

The present study was carried out to evaluate the applicability of the Low Pressure Cold Spray (LPCS) of different powder compositions for depositing multilayer wear-resistant thermal barrier coatings on iron and Al castings. Ni and Cu based coatings with carbide and oxide reinforcements have been sprayed onto ceramic layers made of glass powders and sintered at the temperatures 1000-1200^oC in protective atmosphere. The obtained coatings’ microstructures have been studied by optical microscopy and SEM.  Phase composition, hardness, Young's modulus, adhesion strength and thermal properties of the CS coatings have been analyzed. A “ball on disc” sliding wear test has been used for a preliminary evaluation of the wear resistance characteristics of the metal composite layer.  The composite coatings with WC and TiC reinforcement  that have shown the best performance were selected for further detailed testing in the boundary lubrication conditions.