Fretting corrosion: Analysis of the failure mechanism for low voltage drives applications

In many power electronics products, such as low voltage LV motor drives, the mechanical and electrical connection between printed circuit board assemblies (PCBAs) is obtained though board-to-board connectors. A common failure mechanism for these components is fretting corrosion. This failure mechanism results from mechanical micro-motion of two parts with respect to each other and causes a wear damage at the asperities of the contact surface resulting in an increase of the ohmic resistance which finally triggers various device failures. Failures resulting from interrupted communication path may create different effects at the product level depending on the power electronic circuit diagram. In this paper investigation on fretting corrosion on board-to-board connectors was performed. The chemical composition and microstructural analysis at the junction part of the connectors were performed for as new samples and after aging testing which includes stressors like humidity, temperature, temperature cycling and vibration. Scanning Electron Microscopy (SEM) and energy dispersive X-ray analysis (EDX) showed aging effect on the intermetallic compound (IMC) material correlated to intermetallic growth and oxidation.