| The mullite(3Al₂O₃·2SiO₂) thin films were fabricated by a dipping substrates into coating solution, pulling them up, drying and then heating process. A sol-gel method, 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 adhesion strength of mullite films coated on slide gl-ass was measured with the acoustic emission scratch tester. The critical load of mullite films was measured to be about 14N. Surface hardness could be enhanced up to 2∼3 times that of uncoated substrate by increasing the thickness of mullite films. 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. |
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