STUDY OF WEAR RESISTANCE OF COATINGS DEPOSITED BY HIGH VELOCITY OXYGEN FUEL (HVOF) TECHNOLOGY
Abstract
The contribution deals with the evaluation of wear resistance three types thermally sprayed coatings deposited by HVOF spraying. The wear resistance of these coatings was evaluated by simulation of erosive wear. Erosive wear was simulated by abrasive blast cleaning process using abrasive - brown corundum. Simultaneously there was studied influence of various impact angles on wear resistance of HVOF coatings. Study of properties the coatings was supplied also by measuring thickness, adhesion, microhardness and by EDX analysis. Construction and structure of coatings were studied using optical and electron microscopy. The research results showed that all coatings exhibit comparable resistance against erosive wear, greater weight loss was observed at impact angle 75°. v Adhesion of coatings after heat load slightly decreased, but within 10 thermal cycles stayed relatively stable. Despite these results, it is not possible to recommend to the operational conditions with high and fluctuating temperature neither coating WC-Co-Cr by reason of its thermal cracking nor WC-17Co coating for its strong oxidation during thermal cyclic loading. The best properties in conditions of high temperature showed coating Cr3C2-25NiCr.
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