Abstract

A study of the rate of spontaneous deposition of molybdenumoxides on zinc in ammonia solutions was carried out. Effects of solution pH, disk rotational speed, molybdenum concentration and temperature were evaluated. The process was divided in two stages.The rate of stage 2 was lower than the rate of stage1, this was attributed to the nature of the film formed on zinc surface. The unreacted core model indicates a mixed control, controlled by diffusion through the liquid film and chemical reaction, nevertheless, the results were inconsistent with the diffusion of MoO4-2 because of the rate of the process increases with the decrease in the concentration of molybdate.