Study on antiwear and reducing friction additive of nanometer cobalt hydroxide

Amorphous cobalt hydroxide with a particle size of about 30-50 nm was prepa red using an ethanol supercritical fluid drying technique. Tribological pro perties of a 500 SN oil containing the nanometer particles were measured us ing a four-ball and block-on-ring tribotester. The results indicated that t he wear resistance and load carrying capacity of the oil compared with that of the base oil were raised and the coefficient of friction was markedly d ecreased. An excess of the nanometer additive, however, decreased the maxim um seizure bad of the oil.