The evaluation method of defect rate was examined to determine the defect rate in ceramics film (Cr2O3+SiO2+Al2O3) coated on zirconium alloy by the chemical densification coating method. Chronoamperometry and chemical impedance methods were selected for quantitative determination of defect rate. It is concluded that the chronoamperometry method determines the defect by the rate of change in the minute eletrolysis current in potential step eletrolysis, and that the chemical impedance method established good correlation between defect rate and reciprocal maximum electrical resistance over a wide range of frequency (100mHz-10kHz).
