为检测添加钇对纯钴耐高硫-低氧混合气腐蚀的影响，研究了Co-15wt%Y 合金在600-700℃H2S-CO2 混合气中的腐蚀。合金腐蚀后形成多层结构的腐蚀产物膜，最外层是单一的硫化钴，中间层为由两金属化合物组成的混合物层。最内层是由氧和硫引起的钇的内腐蚀区。在钇含量达到15wt%的条件下未发生钇的选择外硫化/氧化，这与钇在基体金属中的限的固溶度和合金中出富钇金属间化合物有关。
Corrosion of Co-15wt% Y alloy was studied in H2-H2S-CO2 mixtures with 10 -19Pa O2 at 600℃ or 10 -15Pa O2 at 700℃ and with 10 -3 Pa of sulfur pressure.The corrosion rates of the alloy were compared with those of pure cobalt and yttrium.The addition of yttrium to cobalt was only slightly beneficial.For yttrium content of 15wt%,the corrosion rate was reduced only to a limited extent at 600℃,and even slighly increased at 700℃ with respect to pure cobalt.The alloy formed extermal scales of cobalt sulfide containing yttrium sulfide-oxide particles in its inner part.Beneath the external scales,a region of internal sulfidation-oxidation of yttrium was also present.Thus,cobalt cold diffuse through intermediate regiion to form the outer cobalt sulfide layer at significant rates.The yttrium content in this alloy was still insufficient to form cobalt-free external scales.These results were interpretted by taking account of the limited solubility of yttrium in cobalt and the presence of intermetallic Co-Y compound in the alloy.
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