Effect of powder preheating temperature on the properties of titanium coating layers manufactured by kinetic spraying

This study investigated the effect of powder preheating temperature on the properties of titanium coating layers made through the kinetic spray process. Specifically, kinetic sprayed coating layers were made under three different conditions with regard to powder preheating temperatures: no preheating, 500°C, and 800°C in manufacturing processes. Titanium coating layers using pure powder feedstock were made regardless of the powder preheating temperature without any change in phase. The porosity and hardness values of the coating layers were as follows: 3.3%, 281Hv under the no preheating condition; 2.6%, 232 Hv under 500°C preheating, and; 0.4%, 224 Hv under 800°C preheating. As the powder preheating temperature increased, porosity decreased remarkably, and hardness increased; thus enabling the formation of denser coating layer. Note, however, that the thin oxide on the interface of the deposited particles increased as the powder preheating temperatures increased. The optimum process condition for manufacturing pure titanium coating layer was also discussed.