The following describes an analysis performed on dendrites found in a conformally coated module within a frequency generator unit. High-power visual inspection, Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray (EDAX) results confirmed the existence and constituents of the dendrites. For the purposes of this paper, a dendrite is defined as the migration of metal (Ag, Cu, Pb, Sn, etc.) occurring in an electric field with moisture, temperature, and contamination as accelerating factors. This paper addresses the physical aspects of dendrites and not the factors required for growth. Conformal coating is a thin protective layer of silicone material used in electrical assemblies. It is mainly used to prevent particulate contamination and minor mechanical damage but does not protect the assembly against moisture due to its absorption properties.
展开▼
