Optimization of surface properties by flame spray coating and boriding

Investigations have been undertaken on the process of boriding of flame-sprayed coatings. The combination of flame-spraying and boriding has been shown to improve the mechanical properties, especially the surface properties of steels. The flame-spray process offered a good workability, whereas boriding enhanced the hardness, wear resistance and corrosion resistance of the surface, thus optimizing the surface properties. Different boriding media, boriding temperatures and times were compared. The optimum process conditions are suggested, based on the mechanical properties obtained for different conditions. The phase transformation procedure of boriding was investigated, based on the interstitial diffusion model, and the activation energy for the boriding was determined. (C) 1998 Elsevier Science S.A.