Growth morphology and phase analysis of titanium-based coating produced by thermochemical method

In the present study, high-speed tool steel was used to coat titanium by pack cementation technique. Coatings show a growth morphology similar to that of the chemical vapor deposition method. Time and temperature of the coating affects its growth morphology. Coating obtained at low temperature (900 °C) yields morphology with growth of tiny particles while coating produced at high temperature (1000 °C) has a morphology with coarser particles. Phase structure of the layers also varies depending on the process time and temperature. Short coating duration yields TiC0.3N0.7 phase structure, whose composition is close to TiN whereas long coating duration combined with high temperature yields TiC0.7N0.3, whose composition is close to TiC. Mechanical properties such as hardness and resistance to abrasion also reflect changes in phase structures of different types of coating.