Laser Quenching for Ceramic Coated Steels

Abstract

In order to investigate the effectiveness of laser quenching for ceramic coated steels, 3 kinds of ceramic coated specimens of CrN, CrAlN and TiAlN were prepared, and the laser quenching experiments under various irradiation conditions were carried out. The influence of laser irradiation on the substrate hardness, film hardness and adhesive strength were investigated. Because of the high heat absorption of CrAlN, TiAlN and CrN compared to TiN, it was possible to quench the substrate effectively without any absorbent material for these specimens, although an absorbent was required for TiN coated specimen. The quenched area on the cross section of the substrate became larger in the order, CrN coated specimen, TiAlN coated specimen, CrAlN coated specimen. The difference of the quenched area could be explained by the difference of the heat absorption of these films. It was also possible to improve the adhesive strength of these films by laser irradiation. Although the film hardness decreased considerably by furnace quenching for ceramic coated steels, film hardness did not decrease by laser irradiation. It was concluded that the improvement of the adhesive strength and substrate hardness without the decrease of film hardness was achieved by laser quenching for CrN, CrAlN and TiAlN coated specimens.