2015 Volume 56 Issue 1 Pages 85-90
Zinc–nickel–SiO2 electrodeposits have been produced from an acid sulfate bath. The co-deposition behavior of SiO2 and the macro throwing power of plating baths were examined. The presence of SiO2 nanoparticles in the plating bath appears to change the alloy deposition behavior. The rate of nickel deposition was considerably decreased by the presence of SiO2 nanoparticles in the bath. The macro throwing power of plating was improved by adding SiO2 nanoparticles to the bath. At an early stage of electrodeposition, it seems that the SiO2 nanoparticles act as a nucleus for the precipitation. The SiO2 nanoparticles did not disperse uniformly in a plating film; they distributed only in a SiO2 rich layer (∼50 nm thick) that formed beneath the surface. In addition, this SiO2 rich layer can improve anticorrosive performance. Therefore, zincic use can be suppressed because film thickness can be reduced compared to zinc and zinc–nickel alloy electroplating.
