Abstract
The influence of temperature on the morphology and structure of the anodic film on zinc electrode in an alkaline zincate solution was studied under galvanostatic conditions. The oxide film was analyzed by means of an electron microscope and X-ray diffraction. Amount of the oxide film increased when the bath temperature was increased higher up to about 45°C and 55°C in the solutions of 2mol/l KOH and 8mol/l KOH, respectively. A silvery film was formed on the anode in the low temperature range while the film color changed golden in the high temperature range. The reaction rate for the film formation increased remarkably in the high temperature range. The film grew up on the (0002) and (1010) planes of zinc oxide. When the bath temperature reached to 55-60°C, the preferred orientations decreased on the zinc crystal planes of (0002), (1010-2), (1120), (1122), and (2021-3). The zinc crystal was composed of (1013-5) planes at 55-60°C. It was considered that the inhibition of passivation phenomenon could be related to the structure of the oxide film formed on zinc.
