Wet abrasion and slurry erosion resistance of thermally sprayed oxide coatings

Wet abrasion and slurry erosion resistance of alumina and chromia coatings were studied and compared to their dry abrasion resistance. Bulk oxide ceramics and base metals were used for comparison. The coatings were produced by atmospherical plasma splaying. The effect of aluminum phosphate sealing treatment on the wear and corrosion behaviour of the coatings were also studied. in wet abrasion tests kaolin-water and silica-water mixtures were used as the abrasive media. Slurry erosion tests were performed using a slurry pot tester. Quartz sand, alumina and alumina-zirconia in water with various pH values were used as the erosive medium. Dry abrasion tests were performed using a rubber wheel abrasion equipment and quartz abrasive. The coatings and bulk ceramics were characterized for their phase structure, porosity and hardness. The results from wear tests are reported and correlated with coating and bulk ceramic properties. The influence of coating post-treatment to wear behaviour is also presented and discussed. (C) 1999 Elsevier Science S.A. All rights reserved.