SULFIDATION-OXIDATION OF PURE Y AND Co-Y ALLOY UNDER DIFFERENT SULFUR PRESSURES AT 800℃
纯Y和Co—Y合金在800℃不同硫压下的硫化—氧化

The corrosion of pure yttrium and Gl5Y alloy was studied at 8OOC in H2-H2SCQmixtures providing an oxygen partial pressure of 10 -'Pa with sulfur partial pressure of 10 -2 Pa or 10 -Pa. The presence of yttrium is beneficial to reduce the corrasion rate of pure Co. The external scale of cobalt sulfide and yttrium oxide-surfide particles in the inner scale were found respectively after corrasion in Pa .!$ + lo-' Pa Q. Beneath the external scale, a region of internal sulfidation-oxidation of yttrium was also present. The comion pduct in lo-' Pa .!$ + 10-l5 Pa Q was only a very thin surface layer of yttrium oxysulfide and an internal oxidation zone of yttrium. No yttrium depletion was observed in the alloy underneath the internal oxidation zone. ?he corrosion behavior of ;he alloy is thought to be related to the appearance of intermetallic compound and the limited solubility of yttrium in cobalt.