The Al2O3 + TiO2 coatings are of the interest of surface technology and tribology due to their good wear resistance and enhanced toughness comparing to pure Al2O3 coatings. However, the detailed effect of the used feedstock powder, is often neglected. Here, this work focuses on the deposition of Al2O3 + 13 wt % TiO2 coatings by atmospheric plasma spraying (APS) method as well as on their microstructure, phase composition and selected mechanical properties, in the reference to the route of the powder feedstock preparation. The commercial powder Metco 6221 in agglomerated and sintered form was used as a feedstock material during spraying, due to the fact that, so far, sintered or cladded powders are the most studied ones. The 2k + 1 spray experiment allowed to evaluate the influence of two variables, namely spray distance and torch linear velocity, on the coating microstructure. Afterwards, the coating adhesion was measured by the means of pull-off test. The correlations between Vickers microhardness, fracture toughness (Kc) as well as the coating morphology and phase composition were investigated. Finally, the dry sliding wear resistance was studied by using Ball-on-Disc method.

In the paper the results of tribological, microscopic, and mechanical research of Al2O3 + TiO2 coatings manufactured by plasma spraying are presented. The feeding material was a powder Al2O3 + 13 wt.% TiO2 (Metco 6221, OerlikonMetco) with grain size – 45 ± 15 μm. The cylinder substrates made from stainless steel (X5CrNi18-10) had a diameter equal to 25 mm and 2 mm of thickness. The variable spray parameters were plasma torch velocity in terms of substrate and spray distance. The morphology of obtained coatings was tested by scanning electron microscope (SEM), and the microstructure was investigated by light optical microscopy (LOM) and SEM. The results of mechanical properties examinations revealed the dependence of the microhardness and fracture toughness on the spray parameters. Tribological examinations were made in the ball-on-disc mode in technical dry friction conditions. Two loads were used, 5 N and 10 N. Based on the carried out tests, it could be concluded that a shorter spray distance and a reduction of the torch velocity allows one to achieve a more compact structure, which is characterized by good adhesion at the coating-substrate interface (in range from 11 to 14 MPa) and good wear resistance.

In this paper Al2O3 + 13 wt% TiO2 ceramic coatings manufactured by Atmospheric Plasma Spraying (APS) have been investigated. The commercial feedstock materials, Metco 6221 (top coat) and Amdry 4535 (bond coat) have been deposited on stainless steel coupons. The main goal of researches was to determine the influence of critical plasma spray parameters (CPSP) on structure and properties of the coatings. In present studies, the electrical power was a variable parameter. Coatings have been characterized by in the terms of microstructure, topography, bond strength adhesion, fracture toughness and wear resistance. As a result, it was observed, that coatings sprayed with higher value of the electrical power exhibit higher mechanical properties due to better cohesion as well as higher melting degree.

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