WEAR BEHAVIOR OF LASER-TREATED PLASMA-SPRAYED ZRO2 COATINGS

The effect of laser remelting on the wear behaviour of plasma-sprayed ZrO2 ceramic coatings was studied. The results showed that the porosit y and roughness of the coatings were reduced significantly after laser treatment, and the bonding strength was apparently increased by the r emelting process. However, there were extensive network cracks, as wel l as a few large bubbles, in the laser-treated coatings. Unlubricated pin-on-disc wear tests revealed that, when compared with as-sprayed ce ramic coatings, the wear resistance was improved significantly after l aser treatment. The wear resistance of laser-treated specimens increas ed with increasing laser power, and the minimum weight loss of the coa ting specimen occurred at a specific travel speed in laser processing. The main wear mechanism of the as-sprayed coatings was spallation of the coating, whereas the wear of laser-remelted specimens was dominate d by ploughing and gouging (scratching). (C) 1997 Elsevier Science S.A .