The cause of deterioration in PCB (printed circuit board) is due to the migration of copper ion. We carried out bias test under high temperature and high humidity, and discussed the deterioration of PCB due to ionic migration. Some compounds were added in adhesive as impurity and the two adhesives having different glass transition temperature were used to adhere copper with polyimide film. The development of the ionic migration resulted in the decrease of deterioration time. The deterioration time became short with the increase of impurity content and with the decrease of glass transition temperature.

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We studied the deterioration process of nitrite rubber (NBR) in a micro and detailed manner through the ozone exposure test. The surface of ozone-deteriorated NBR was sliced by microtome. The crack behavior and the ratio of element on the ozone-deteriorated surface were examined in detail by microscope and ESCA. We found that the cracks were formed perpendicular to the stress direction, which is peculiar to the ozone deterioration.The deterioration was accelerated remarkably with the increase of ozone concentration and, however, occurred only very thin surface in a relatively short time. According to the surface analysis by ESCA, the ratio of oxygen and nitrogen atoms increased with the deterioration time, while the ratio of carbon atom decreased.

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