美国通用汽车公司研究实验室开发了一种疲劳裂纹凝胶电极检测法,该方法的灵敏度足以检测出铝制零件上长度为0.01mm的表面裂纹。使用本方法时,先将零件清洗干净,然后涂上一层氧化薄膜。在疲劳试验期间,疲劳裂纹处的氧化膜发生断裂,从而使氧化层厚度减小。试验之后,将表面涂上含有碘化钾和谷物淀粉的柔性凝胶。然后在凝胶与铝试样之间加上低压脉冲,一般为4V,时间为100ms。碘离子带着电流优先流到疲劳裂纹,因为此处的碘化层变得较薄, General Motors Corporation of America research laboratory developed a fatigue crack gel electrode test method, the sensitivity of this method is sufficient to detect aluminum parts on the surface length of 0.01mm crack. When using this method, first clean the parts, and then coated with a thin layer of oxide film. During the fatigue test, the oxide film at the fatigue crack breaks, reducing the thickness of the oxide layer. After the test, the surface is coated with a flexible gel containing potassium iodide and corn starch. A low voltage pulse is then applied between the gel and the aluminum sample, typically 4V, for a period of 100ms. Iodine ions flow preferentially to fatigue cracks with current because the iodide layer becomes thinner here,