Ni-coated Al2O3 powders

A heterogeneous precipitation method was employed to prepare Ni-coated-Al2O3 powders using Al2O3, Ni(NO3)(2).6H(2)O and NH4HCO3 as the starting materials. The coated powders were characterized by TEM. AES, zeta-pH. Results showed that a continuous amorphous NiCo3.2Ni(OH)(2).2H(2)O film uniformly coated the Al2O3 particles surface. After calcining at 400 degreesC for 2 h in air and reducing at 700 degreesC for 4 h in hydrogen atmosphere, NiCO3.2Ni(OH)(2).2H(2)O was converted to Ni with size of about 20 nm, meanwhile, the continuous amorphous film become discontinuous. (C) 2002 Elsevier Science Ltd and Techna S.r.l. All rights reserved.