Ni-coated Al2O3 powders

A heterogeneous precipitation method was employed to prepare Ni-coated-Al2O3 powders using Al2O3, Ni(NO3)2·6H2O and NH4HCO3 as the starting materials. The coated powders were characterized by TEM, AES, ζ-pH. Results showed that a continuous amorphous NiCO3·2Ni(OH)2·2H2O film uniformly coated the Al2O3 particles surface. After calcining at 400 °C for 2 h in air and reducing at 700 °C for 4 h in hydrogen atmosphere, NiCO3·2Ni(OH)2·2H2O was converted to Ni with size of about 20 nm, meanwhile, the continuous amorphous film become discontinuous.