Dendrites/ Electrochemical Migration
Under certain conditions corroded metal is redeposited as a metallic filament called a dendrite. A dendrite will cause a direct short if it bridges the gap between conductors, but even in the absence of a direct short circuit the current flow associated with electrolytic corrosion can cause problems.
Dendrite Inspection / Electrochemical migration
Metal components of a circuit board can be induced to corrode by the application of an applied voltage whenever surface moisture supports current flow. The presence of ionic materials promotes the surface conduction and greatly accelerates the electrolytic corrosion. The corrosion products remain near the corrosion site or are transported a short distance across the surface of the circuit board by ionic migration. Under certain conditions the corroded metal is redeposited as a metallic filament called a dendrite. A dendrite will cause a direct short if it bridges the gap between conductors, but even in the absence of a direct short circuit the current flow associated with electrolytic corrosion can cause problems.
Electrolytic corrosion can occur under conditions that do not promote metallic dendrites; however, the industry tends to refer to all superficial electrolytic corrosion deposits as dendrites.
Description of dendrite inspection
Visual inspection is used to detect electrochemical migration and dendrites. Circuit boards are optically examined at magnifications up to 50X. If features of electrolytic corrosion or dendrites are observed the circuit board may be examined using scanning electron microscopy. Energy dispersive spectroscopy can be used to identify the corroding elements and corrosion accelerating ions such as chlorine and bromine.
Deliverables
Elmet documents the inspections with representative photographs of the circuit board and all occurrences of electrochemical migration. All photographs, SEM images, EDS analyses, and a summary of the findings are presented in a written report.
What to do next
Please email or call us if you have questions. If you are ready to ask for a quote, we would first like to see a photograph or layout of the circuit board. We also need to know how many circuit boards you want inspected. Or, visit our Price Estimation form if you want a fast, informal idea as to scope of your project!