Solder degradation

This method is the simplest of all the methods and is capable of detecting surface flaws such as corrosion, contamination, surface finish and surface discontinuities on joints.47 The discontinuities on joints such as welds, seals, solder connections and adhesive bonds can be detected. General corrosion, qualitative pitting corrosion, stress-corrosion cracking, weld-heat-affected zone attack, erosion corrosion and other type of degradation can be observed by visual examination aided by microscopes with sufficient magnification. Degradation of plastics can also be detected by visual examination. Visual examination is also used in conjunction with other techniques, such as powerful microscopes. 

Here / is the cycle frequency, Nf the number of cycles to failure, and AT the temperature difference. The Coffin-Manson model is widely accepted for describing material degradation (e.g., solder materials), fatigue fracture, and crack propagation. 

Platinum inks are the most expensive thick film conductive ink, but are occasionally used where extreme resistance to molten solder and to bold strength degradation by solder is required. 

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