Study of the influence of induction-heat treatment on the morphology of titanium plasma-sprayed coatings

The work investigated the effect of induction heat treatment (IHT) on the morphology of titanium coatings obtained by plasma spraying (PS). IHT of titanium samples was carried out at temperatures of 650±50 and 1200±50 °C and duration of 120 s. It was found that the porosity of the PS coating was 57±3 %. The average grain size was 9.57±0.2 μm, and the pore size was 13.01±0.5 μm. The thickness of the formed layers was 320±30 μm. Thermal modification at an inductor current of 2.6 kA led to an increase in the average grain size to 11.12±0.3 μm, the pore size remained practically unchanged and amounted to 12.40±0.4 μm, the surface porosity of the coating also did not change and remained equal to 58±5 %. The thickness of the modified layers decreased to 265±20 μm. With an increase in the inductor current to 8.0 kA, the average grain and pore size decreased to 8.95±0.2 and 8.12±0.2 μm, respectively. The porosity of the modified layer did not change and remained equal to 56±1%. After the modification process, the scale peeled off from the coating surface, which led to a decrease in the thickness to 197±25 μm. The study of adhesion strength by a qualitative method showed that this parameter increased after IHT.