超超临界耐热钢高温水蒸汽抗氧化性比较.PDF

      超(超)临界耐热钢高温水蒸汽抗氧化性比较 程从前、 刘宜萱、赵杰 （大连理工大学材料科学与工程学院，辽宁 大连，116085） 摘要：采用电化学阻抗、氧化增重、SEM 和 XRD 等分析了 Super304H、P92 在 554℃和 645℃ 24MPa 超临界水中氧化 44h 后的表面产物特性，并与 15CrMo 比较，发现称重法不能表征Super304H 氧化前后变化，P92 和 15CrMo 有氧化增重但无法 通过增重反映两种钢的差异；Super304H 表面由细小的针状或颗粒状的含 Fe 和 Cr 的氧化物组成，P92 和 15CrMo 表面为相 对较大的颗粒状 Fe3O4 组成；554℃超临界水氧化后在NaCl 溶液中的阻抗由小至大顺序为：P92<Super304H<15CrMo ，随温 度升高阻抗增大；结果表明电化学阻抗可在短时氧化条件下评估耐热钢的抗氧化特性。 关键词：耐热钢、超临界水、氧化、电化学阻抗 Comparison of Oxidation Resistance of Several Heat Resistant Steels in Supercritical Water CHENG Cong-qian, LIU Yi-xuan, ZHAO Jie (School of Material Science and Engineering, Dalian University of Technology, Dalian ；116023) Abstract ：Surface oxide scales on Super304H and P92 after being oxidized in 554 ℃ and 645 ℃ 24MPa supercritical water for 44 h were examined by electrochemistry impedance spectra (EIS), weight increment, SEM and XRD, and were compared to 15CrMo. No obvious weight increment was observed for Super304H. Although the weight of P92 and 15CrMo has increased after oxidation, there is no difference of weight increment for these two steels. Surface product on Super304H is composed of tiny pin-type and granule oxides containing Fe and Cr elements, while the surface oxide scales on P92 and 15CrMo are composed of Fe O particles. The 3 4 impedance sequence of the samples in 3.5% NaCl solution after oxidation in supercritical water at 554 ℃ is P92<Super304H<15CrMo, and the impedance increases with increasing temperature of supercritical water. It suggests that the EIS technology can be used to evaluate the oxidation resistance o