Abstract
Although thermal spraying technique is used in many industries, it suffers from several problems. For example, the hardness of the coatings is lower than that of sintered material for the incompleted cohesiveness. An yttrium aluminum garnet (YAG) laser was used during HVOF spraying to improve the properties of the applied coating. Several carbide powders were used as thermal spray materials, and stainless steel (SUS304) was used as substrate. Coatings were sprayed by hybrid spraying method, which was combined HVOF spraying with YAG laser. The hardness of coatings sprayed by hybrid spraying was higher, and the weight loss in a blast-erosion test was smaller than that of coatings applied by HVOF spraying only. The particles deposited in the coatings obtained by hybrid spraying were very fine. Laser irradiation to the HVOF flame improve the adhesion strength between particles and the deposition of fine carbide particles in the coating. It was considered that mechanism of coating strengthening in hybrid spraying was resulted from strengthening of cohesiveness by heating effect and decreasing of porosity by flattening effect according to observation results of Ni splats sprayed by hybrid spraying method.
