2004 Volume 45 Issue 6 Pages 1864-1868
The thermal spraying technique is used in many industries, for example, the automobile industry and the steel-making industry. However, the process suffers from several problems, because cohesion between particles in the coating may be incomplete. It is very difficult to anneal the coating by heat treatment, because of deformation of the substrate and the hardness of the coatings is less than that of sintered coatings. An yttrium aluminum garnet (YAG) laser was used during high-velocity oxy-fuel (HVOF) spraying to improve the properties of the applied coating. The spray material was Cr3C2-Ni-Cr, and the substrate was stainless steel (SUS304). The YAG laser was combined with HVOF spraying by irradiating the spraying point on the substrate. The coatings obtained were compared with a coating sprayed by HVOF spraying without the YAG laser. The hardness of coatings sprayed by HVOF with YAG laser treatment was higher, and the weight loss in a blast-erosion test was smaller, than for comparable coatings applied by HVOF spraying alone. The particles deposited in the coatings obtained by HVOF spraying combined with a YAG laser were shown to be very fine. Laser irradiation to the HVOF flame results in strong adhesion between particles, and the deposition of fine carbide particles in the coating.