| Al₂O₃, Chin films were fabricated by a dipping method. A Sol-Gel process, which comprises precipitation of aluminum monohydroxide, was used to produce coating solutions. Thickness of the films increased with increasing the viscosity of solution and the number of coating cycle. The relationship of the film thickness and viscosity using Nevier-Stokes equation was proposed, and it showed good agreements with film thickness measured in the range of low viscosity. The adhesion strength of Al₂O₃films coated on stainless steel was measured with the acoustic emission scratch tester. The critical load of Al₂O₃ films was measured to be about 14 N. Surface hardness could be enhanced up to 3.4 times that of uncoated substrate by increasing the thickness of Al₂O₃films to 12㎛. Electric resistance was 60Ω for layers of 13㎛ thick. This value is corresponding to that of an insulator. According to the corrosion test, it turned out that thicker the coating layer became, less was the total corrosion rate. This was attributed to the decrease in porosity. |
|
