Tribological properties of HVOF sprayed tungsten carbide coatings modyfied by the EDM process

W pracy podjęto próbę wytwarzania przeciwzużyciowych warstw powierzchniowych hybrydową metodą naddźwiękowo-elektroiskrową. Powłoki z WC12Co i WC17Co zostały naniesione systemem do natrysku naddźwiękowego TAFA–JP-5000. Modyfikacja powłok obróbką elektroerozyjną została wykonana za pomocą urządzenia ELFA-541. Ocenę własności powłok przeprowadzono na podstawie analizy mikrostruktury, badań tribologicznych oraz pomiarów mikrotwardości i chropowatości.Wear and abrasion are still up-to-date problems in all branches of industry. Although modern technologies permit considerable improvement in the properties of the outer layer, they need to be constantly modified or new solutions have to be looked for. HVOF-sprayed coatings are frequently used to improve the service life of machine components. The influence of the spray parameters and material type on the coating properties has been analysed thoroughly by numerous researchers. This study focuses on the tribological properties of two HVOF-sprayed tungsten carbide coatings, each with a different content of cobalt, which were subjected to electrical discharge machining (EDM). The material deposited over the HVOF-sprayed coatings was tungsten carbide. The microstructure of the sprayed and electro-discharge-machined coatings was analysed with a JOEL JSM-5400 scanning microscope. A ball-on-disc test was conducted to determine the coefficients of friction. The EDM process results in the formation of a homogeneous layer of tungsten carbide with a low cobalt content, which is well bonded with the HVOF-sprayed coating. The values of the coefficient of friction obtained for the two coatings with the EDM layer were similar