Evaluation of Effect of Film Defects on Hydrothermal Corrosion Resistance of Metallized Aluminum Nitride Ceramics by Statistics of Extreme

摘要

In order to investigate the degradation of AlN substrate in hydrothermal environments, AlN ceramics coated with two kinds of electroless plating films, such as Ni-P and Cu, were exposed in water at 373K up to 10 days. The depth and the size of individual defects in the plating film were measured by a microscope and the maximum depths were estimated by the statistics of extreme. The maximum depths of early film defects in the plating films obeyed the double exponential distribution. In the case of Ni-P/AlN, the degradation of AlN substrate was caused by early film defect in the plating films such as pinhole and not by corrosion. The degradation of the AlN substrate with Cu plating film occurred by corrosion not by early film.