2015 Volume 64 Issue 5 Pages 188-192
This study was carried out to examine the effect of silver surface temperature on sulfide formation behavior in sulfur vapor at constant temperature. QCM was used to measure mass change by silver sulfide formation. In a closed glass container, flowers of sulfur, S8 were placed as a sulfur source and QCM prepared by vacuum deposition of silver was exposed. The temperature of the testing environment, T1 was controlled by an oven and the silver surface temperature, T2 was varied by an aluminum foil heater. The saturated sulfur vapor pressure p was calculated from T1 using Antoine’s equation. The results showed that in the case of T1=T2, the corrosion rate increased linearly with increasing p. In the case of T1＜T2, at p=8.3 and 24 mPa, the corrosion rate increased with T2, while at p=2.6 mPa, the corrosion rate remained almost constant with T2. This result indicates that in this environment, natural convection generated by heating the silver surface caused the corrosion rate increased by facilitating the supply of sulfur molecules to the silver surface. The degree of natural convection (T1－T2)/T1 and p determine the corrosion rate increase.
