The rate of electroless deposition of a four-component Ni-W-P-ZrO_2 composite coating from a glycine bath

摘要

Four-component Ni-W-P-ZrO_2 composite coatings were electroless deposited. A bath containing aminoacetic acid as the agent complexing nickel ions, and sodium tungstate(VI) as the source of tungstate was used. It has been determined that as the bath's pH increases (from 5 to 6) so does the rate of coating deposition while the phosphorus content in the coating decreases. Both an increase in the aminoacetic acid concentration and an increase in the sodium tungstate cause a reduction in the rate of deposition of the Ni-W-P-ZrO_2 coating. Changes in the concentration of the two components in the bath result in a change in the composition of the coatings. When the concentration of the components is too high the bath loses its stability and a sediment precipitates itself. The ZrO_2 content in the coating depends most on the amount of this powder in the suspension.