Effect of Substrate Preheating on Adhesive Strength of SS 316L Cold Spray Coatings

This paper aims at improving the adhesive strength of SS 316L coating by substrate preheating (400, 600, and 700 degrees C). The relationships between the adhesive strength of coating/substrate interface and the substrate preheating temperature are discussed. It was found that stronger adhesion is able to occur despite the presence of a thick oxide film on the substrate surface. The preheated substrate surface undergoes a stronger plastic deformation that disrupts the oxide films for obtaining an intimate contact between particle and substrate material. In addition, the oxide films on the substrate surface can prevent the generation of material jet of the substrate. The effects of substrate preheating on the microstructure and hardness were also investigated.