Centrifugal pumps are used to transport the ash slurry from the thermal power plant to ash pond. Erosive wear occurs on the impeller of the pump due to the impingement of the ash particles, suspended in water, on the impeller with a high velocity. In the present work, three parameters were selected to investigate the erosive wear i. e., rotational speed, ash concentration and ash particle size. Detonation gun sprayed Al2O3 coating is provided on the surface to reduce the erosive wear and hence to improve the performance of centrifugal pump. The experimentation on high speed slurry erosion tester has been carried out to test the erosive wear of uncoated and coated material. The erosive wear behavior was investigated by Response surface methodology.