Effect of Heat Treatment on the Microstructure and Properties of HVOF-Sprayed Co-Cr-W Coating

0472798 - ÚFP 2017 RIV US eng J - Journal Article
Houdková, Š. - Smazalová, E. - Pala, Zdeněk
Effect of Heat Treatment on the Microstructure and Properties of HVOF-Sprayed Co-Cr-W Coating.
Journal of Thermal Spray Technology. Roč. 25, č. 3 (2016), s. 546-557. ISSN 1059-9630. E-ISSN 1544-1016
Institutional support: RVO:61389021
Keywords : ASTM * G-65ASTM * Co-Cr-W * heat treatment * HVOF * Stellite 6 * wear
Subject RIV: JK - Corrosion ; Surface Treatment of Materials
Impact factor: 1.488, year: 2016

Co-Cr-W HVOF-sprayed protective coatings are used for their high oxidation and wear resistance. Apart from the oxidation resistance, the stability of their mechanical properties in relation to thermal loading is crucial with respect to the most common high-temperature application areas. This work is focused mainly on evaluation of the heat-induced changes in the phase composition and related mechanical properties. It was shown that the original powder, composed fully from face-centered cubic Co-based alloy, partly changes its phase composition during spraying to a hexagonal close-packed (hcp) structure. The annealing further increases the ratio of the hcp phase in the structure. The heat-induced phase changes are accompanied by an increase in the coatings' hardness and cohesion strength. The abrasive and adhesive wear behavior was evaluated. While the coatings' heat treatment had a positive effect on the coefficient of friction, the abrasive and adhesive wear resistance of annealed coating was lower compared to as-sprayed coating.
Permanent Link: http://hdl.handle.net/11104/0270013