The Effects of In-situ Powder Preheating on Cold Sprayed Coatings

摘要

Cold spray is an emerging technology that addresses many of the shortcomings of conventional thermal spray processes. The coatings in cold spray process are formed only by high-velocity particles impacting on the substrate to be coated. One of the main characteristics of the cold spray is solid state coating process. This article reports on the effects of in-situ powder preheating on the deposition efficiency, tensile bond strength, hardness, and porosity of the coatings deposited by the cold spray using Ni and Cu powders. The test results show that as the powder preheating temperature is increased, the deposition efficiency of the coatings is linearly increased. However, the effect of powder preheating on the hardness and porosity of the coatings seems to be negligible. Failure occurs at the epoxy bond except very weak coating when the tensile bond strength of the coatings is tested. Thus, it can be concluded that tensile bond strength of the coatings by the cold spray is above 1000 kg/cm~2.