Abstract: Nano-Ni-coated-A1₂O₃ composite powder was prepared by the heterogeneous precipitation method. The amorphous NiCO₃·2Ni(OH)₂·2H₂O was uniformly coated on the surfaces of Al₂O₃ particles. The amorphous coating layers were crystallized to NiO at 550℃ for 2h in air. NiO was completely reduced to Ni at 700℃ for 4h in hydrogen atmosphere. Ni with the size of about 20nm in the coating layers was spherical and weakly agglomerated. The continuous coated layers became discontinuous during heating treatment.

Key words: Ni-coated Al₂O₃, heterogeneous precipitation, continuous, discontinuous