时效时间对2205双相不锈钢抗氢氟酸腐蚀性能的影响  

Effect of Aging Time on Corrosion Resistance of 2205 Duplex Stainless Steel in Hydrofluoric Acid

作　　者：安朋亮 宋菲[1] 梁平[1] 秦华[1] 赵艳[1] 逄旭光[1] 

机构地区：[1]辽宁石油化工大学机械工程学院,抚顺113001

出　　处：《腐蚀科学与防护技术》2017年第4期421-425,共5页Corrosion Science and Protection Technology

摘　　要：析出物会影响2205双相不锈钢在氢氟酸溶液中的腐蚀性能。为了了解这种影响,通过金相显微镜观察了固溶处理后的2205双相不锈钢经800℃时效处理15,60和120 min的显微组织,采用X射线衍射技术分析了时效不同时间下的物相结构,借助电化学极化和电化学阻抗方法测试了时效时间对2205双相不锈钢抗氢氟酸腐蚀行为的影响规律。结果表明:当时效时间为15 min时,双相不锈钢内就已析出了σ相,且σ相体积分数随着时效时间的延长而增大。随着时效时间的延长,2205双相不锈钢在氢氟酸溶液中的自腐蚀电流密度和维钝电流密度都呈逐渐增大趋势,抗氢氟酸腐蚀性能下降,这主要是因为析出的σ相导致钝化膜内的载流子密度逐渐增大,加快了电子的传输速度,电化学反应更容易发生。The corrosion behavior of 2205 duplex stainless steel（DSS） in hydrofluoric acid was affected by the precipitates. To understand the change for corrosion behavior of 2205 DSS caused by the precipitates, the 2205 duplex stainless steel（DSS） was aging treated at 800 ℃ for 15, 60 and 120 minutes. The microstructures were observed by means of optical microscope（OM）, and the phases in the heat-treated DSS samples were also characterized by X-ray diffraction（XRD）. The corrosion resistance of differently heat-treated DSS samples was examined by means of potentiodynamic polarization, electrochemical impedance spectra（EIS） and Mott-Schokkty plots. The results showed that the σ phase was precipitated when 2205 DSS was aged for 15 minute at 800 ℃, and the volume fraction of σ-phase was increased with increasing aging time, while the fraction of ferrite phase was decreased. The free corrosion current and passive current density increased with increasing aging time, and the corrosion resistance of 2205 DSS in HF was descended with the increasing aging time. This was mainly ascribed to that the precipitation of σ phase resulted in the increase of carrier density in the passive films, which promoted the transmission of electrons, therewith, the electrochemical reaction was increased.

关 键 词：2205双相不锈钢 时效处理 氢氟酸 Σ相 钝化膜 

分 类 号：TG174.42[金属学及工艺—金属表面处理]