Microstructure, hardness and abrasive wear behaviour of flame sprayed Co based alloy coating

In the present paper, the influence of the post-spray heat treatment on microstructure, microhardness and abrasive wear behaviour of flame sprayed stellite ( EWAC 1006 EE) coatings deposited on mild steel has been reported. Coatings were deposited by oxyacetylene flame spraying torch. The post-spray heat treatment of the coatings was carried out at 800 degrees C for 2 h. Wear behaviour of coatings was evaluated using pin on plate wear system against SiC abrasive medium of 120 and 600 grade at 5, 10, 15 and 20 N normal load. It has been found that the influence of normal load on wear behaviour of these coating is governed by the microstructure, hardness and abrasive grit size. Heat treatment decreases average microhardness of the coating. Heat treatment improved the abrasive wear resistance against fine grit size abrasive medium, while it deteriorated wear resistance against coarse abrasive. Scanning electron microscopy ( SEM) study indicates that the wear is largely governed by groove formation, microcutting and scoring mechanisms.