Preparation of nano α-alumina powder and wear resistance of nanoparticles reinforced composite coating

Nanometer α-alumina powder was synthesized using the pore rich activated carbon as the reaction place, and the α-alumina nanoparticle reinforced nickel based composite coating was prepared by flash thermal spray method. The composite coating was abraded on abrasive wear-machine to study its wear resistance property. The results showed that a large number of uniform size spherical-shaped precursor particles were in the activated carbon pores, which could be long-term stable in a spherical shape and adsorbed on the pore wall. In addition, activated carbon pores could prevent the alumina particles from growing up and reuniting effectively during the precursor particles calcination process. And the activated carbon had completely burned at high temperature as well. Finally, nano α-alumina powder with good dispersion was obtained. The wear resistance of the nickel based composite coating was reinforced by the nanometer α-alumina powder. With 2% volume fraction addition of nanometer α-alumina, the coating has the best abrasive wear resistance property.