含碲钴基高温合金熔盐腐蚀行为

Corrosion Behavior of Cobalt-Based Superalloys with Tellurium in Molten Salt

非真空环境下烧结不同Te含量的钴基合金粉末,研究其在静态800±5℃,75%Na_2SO_4+25%NaCl下的高温熔盐腐蚀行为,采用OM、SEM和XRD分析了合金金相组织、腐蚀产物形貌和物相组成。结果表明:随着钴基合金中含Te质量分数的增加,合金的高温熔盐腐蚀速率逐渐降低;当Te含量为1.6%左右时,合金基体表面形成均匀、致密的Cr_2O_3氧化保护膜及弥散在基体中的新相(CoTeO_3、Fe_2TeO_5)抑制Co原子向晶界扩散,延缓合金基体元素溶解,平均腐蚀速率由不含Te的4.0483 mg/(cm^2·h)降低至0.216 mg/(cm^2·h),提高合金耐热腐蚀性能。

The corrosion behavior in high temperature molten salt of cobalt-based alloy powder with different Te contents that was sintered under non-vacuum environment was investigated in a static 800±5℃ and 75% Na2504＋25% NaC1. The microstructure, corrosion product morphology and phase composition were investigated by OM, SEM and XRD, respectively. The results show that with the increase of Te mass fraction in cobalt-based alloy, the high-temperature molten salt corrosion rate decreases gradually; when the Te content is about 1.6%, a kind of homogeneous and dense Cr2O3 protection oxide film forms on the surface of the alloy substrate and the new phase （CoTeO3, Fe2TeOs） dispersed in the matrix inhibits Co atoms from diffusing to grain boundaries, which retard alloy matrix element dissolution and improve the hot corrosion performance of the alloy. The corrosion rate of cobalt-based alloy decreases from 4.0483 mg/（cm2.h） of the Te-free alloy to 0.216 mg/（cm2.h）.