Corrosion testing of electronic units (NT TR 590)

Abstract

  Nowadays, the demand for better and reliable products is high, whereas the time between the idea of a product and the production decreases. This is especially the case for products containing electronics, which are part of our everyday. Because electronic products are submitted to all kinds of environments, especially corrosive environments, the demand for adapted corrosion testing methods assuring their well functioning after years of use is needed. Such methods have to give a realistic picture of the damages that are encountered in reality, but they also have to give a fast response. In this project, a well proven corrosion testing method (ISO 21207 Method B) combining humidity cycling with conditioning followed by drying as well as exposure to corrosive substances like sulphur dioxide, nitric oxide and salts, was modified in order to increase even further the acceleration factor of the corrosion attacks. The modification, including a larger weekly dose of corrosive gases and salts, was tested on reference panels of pure metals (copper, zinc, carbon steel, aluminium and stainless steel) and a selection of tests objects from the car and electronic industries. The corrosion damages on the objects tested with the modified corrosion testing method showed good agreement with damages observed after exposure to real environments. Moreover, the method could be used to verify the tightness of seals of encapsulated test objects, by the insertion of coupons and thin threads of copper. However, the acceleration factor of the modified method was only slightly higher than the acceleration factor of the original corrosion testing method.