Research of the morphology and microhardness of titanium plasma-sprayed coatings after thermal modification at different pressures of the working medium
Elena O. Osipova1, Olga A. Markelova1, Pavel A. Palkanov1, Vladimir A. Koshuro1, Aleksandr A. Fomin1 1 Yuri Gagarin State Technical University of Saratov, Saratov, Russia
Abstract
Plasma spraying (PS) is widely used in medicine. The main disadvantages of this method are low adhesive strength and cracking of the coating. To improve the mechanical characteristics of the formed coatings, induction thermal treatment (IHT) is used, which makes it possible to form nanosized structural elements on the titanium surface. In the work, the influence of the atmosphere during IHT on the morphology and microhardness of titanium PS coatings was studied. Samples with pre-sprayed titanium coatings were subjected to induction heat treatment in air and in a technical vacuum at a pressure (30–40 Pa). At a processing temperature of 900-950 ˚C. The processing time was 120 and 300 s. As a result of the research, it was found that the pressure of the reaction medium affects the morphology and microhardness of the coatings. An SEM study found that particles from prismatic, elongated crystals change to spherical ones. The use of reduced pressure during heat treatment led to a decrease in the size of structural elements from 2–5 μm to 100–200 nm. The change in structural elements and oxygen content led to a decrease in the microhardness of the modified titanium coatings from 1553±249 HV0.98 to 1002±292 HV0.98 compared to the treatment in air.
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Elena Osipova
Yuri Gagarin State Technical University of Saratov
Russia
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