Corrosion in Power Electronics

Abstract:
Corrosion on electronic and power electronic devices is one of the major effects, which negatively affect the reliability of the respective device. The ZESTRON experience from over many years of failure analysis and risk assessment in this area clearly reveal that in power electrics especially the anodic migration phenomenon (AMP) is the corr osion mechanism most often found under high voltage conditions in combination with high humidity load. This study shows that the AMP is a deviation from the “basic mechanism” electrochemical migration, which is commonly known from low voltage applications. When occurring in power electronic devices, this failure mechanism changes from a cathodic-anodic migration phenomenon to an anodic-cathodic one especially in and under polymer materials used e.g. for isolation purposes. Based on actual failure cases, it will be explained in detail why this change in growing direction of the optically visible dendritic structures happens.