Acceleration of Electrochemical Migration under Sulfur Dioxide Gas Environment and its Mechanism.

Abstract

The purpose of study is to clarify 1) the acceleration effect of SO₂ gas on the generation of migration, and 2) the generation mechanism of migration under the SO₂ gas environment. The experiments were carried out using the circuit board set in the cycle testing tank controlling temperature and humidity. The voltage applied to the test wirings was 50 V. SO₂ gas concentrations were 0, 0.3, 12 and 85 ppm. Distances between wirings were 0.16, 0.4, 1, 2.5 and 6.3 mm. The one cycle of the cycle testing was first (5°C, 60%RH, 20 min.) and second (25°C, 90%RH, 20 min.). The results show that the progress of the migration in SO₂ gas environment is accelerated by changing the water absorbed on the surface between wirings into acid water caused by SO2 gas and migration with wirings of 6.3 mm distance was observed.