Effects of laser heat treatment on mechanical properties of ceramic coated steelsPart 2 - Fracture strength of laser heat treated ceramic thin film.

In our previous study, we proposed a new surface modification technique by combination of ceramic coating and laser heat treatment. By applying laser heat treatment after coating, it was possible to improve the adhesive strength and substrate hardness of ceramic coated steels without compromising the film hardness. However, the effects of laser heat treatment on the fracture strength of ceramic thin films were not investigated yet. In the present research, in order to demonstrate further development of this method, the fracture strength of laser irradiated ceramic thin films (CrAlN, TiAlN and CrN) was investigated by sphere indentation testing. To prevent heat induced changes in the substrate hardness, a cemented carbide WC–Co rather than steel was used as substrate material. While the fracture strength of each film decreased significantly through furnace heat treatment, it remained almost unchanged in case of the laser irradiated films. The application of laser heat treatment for the substrate quenching after coating process can effectively prevent the fracture strength loss of ceramic thin film. [ABSTRACT FROM AUTHOR]