MODIFICATION OF COMMERCIAL POWDER BY ADDITION OF Al POWDER FOR OXIDATION RESISTANT HARD SURFACING BY THERMAL SPRAYING

Abstract

In present study, commercially available Ni alloy powder (EWAC 1005 EC) was modified by addition of 2% Al powder, with help of attritor. Then both Original & Modified powder were sprayed on mild steel substrate by powder flame spraying process. Coatings produced by thermal spraying process, were tested for wear resistance on "pin on disc" wear testing machine at normal load 2.5, 3.5, 4.5 kg. It is found, that Original powder coating, shows comparatively better wear resistance at all normal loads of test than that Modified powder coating. Both Original & Modified powder coated specimen were tested for oxidation resistance at constant temperature 800°, 850°, 900°C and under cyclic heating. It is found that Modified powder coating has better oxidation resistance at constant temperature(8000, 850°, 9000C)than that of original powder coating under the same conditions. But under cyclic heating conditions, original powder coating shows better oxidation resistance than that of Modified powder coating.