Basic knowledge and latest trend of thermal spray process

Thermal spraying is a method of heating a spray material utilizing combustion or electric energy and spraying particles in a molten or semi-molten state onto the surface of the substrate. It has characteristics such as low temperature process, high coating rate, high productivity, wide variety of materials such as metals and ceramics can be used and coating on large products is also possible, etc. In recent years, practical use in the industrial field such as aero, power generation, automotive, etc. is increased. On the other hand, there are some problems in the coating performance, such as pores and oxides remain in the coating. These problems have been overcoming by the development of low pressure plasma spray and HVOF technology and are also being applied to chromium plating alternative applications which are required to have dense structure for corrosion resistance. New attempts have also progressed to get a higher performance and develop new coating. In this paper, basic knowledge and latest trend of thermal spray process are described. © 2019 Japanese Society of Tribologists. All rights reserved.