WEAR BEHAVIOUR OF PLASMA-SPRAYED Al-12Si/SiC COMPOSITE COATINGS UNDER DRY AND WATER-LUBRICATED SLIDING

Powders of Al-12Si with 25 and 50 wt %SiC particles were ball milled in a conventional rotating ball ma with alumina balls for 2h. The milled powders were plasma sprayed on to aluminum and stainless steel substrates to obtain Al matrix composites with high SiC weight fraction. The microstructure characteristics of the sprayed composites were investigated by metal microscopy, x-ray diffraction and scanning electron microscopy. Surface roughness, coating thickness and micro hardness tester were measured. The obtained results point out that an increase of SiC particles in Al-12Si coatings was caused on the rising of the micro hardness values. The wear behavior of the coatings under dry-sliding and water-lubricated sliding against WC/Co counter material was studied using ball on disc for different loads. Increasing SiC content of coatings increase the wear resistant. Finally, the highest wear resistances of coatings were also found in the %20 SiC coating.