Substrate pre-treatment by dry-ice blasting and cold spraying of titanium

With the aim of avoiding the composition modification of titanium particles and substrate degradation during conventional thermal spray process, a combination process of cold spraying and dry-ice blasting was used in the present study to deposit titanium coatings on different metallic substrates. Moreover, a tentative study on cold spraying of titanium coatings on non-metallic surfaces such as polymers was carried out by profiting the texturing potential of dry-ice blasting. The deposition characteristics of titanium particles were examined in terms of deposition efficiency, coating microstructure, microhardness and bonding strength. Only several titanium particles were embedded into polymer with no build-up of a layer or coating in spite of dry-ice blasting application. Titanium coatings coated on metallic substrates exhibited a porous structure and no obvious difference in outer and inner microstructure was distinguished. In addition, dry-ice blasting has a positive improvement in bonding strength between titanium coatings and relatively soft metallic substrate.