环境因素对两种不锈钢在模拟海水中点蚀行为的影响
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摘要
采用动电位极化、恒电位下临界点蚀温度(CPT)测量和腐蚀形貌观察方法对比研究了环境因素对Z2CND18-12N奥氏体不锈钢和S32760双相不锈钢在模拟海水环境中的点蚀行为。结果表明:每种材料在30℃人造海水和3.5% NaCl溶液中的极化行为相似,S32760的点蚀电位Eb均在+1 100mV(相对于饱和甘汞电极SCE,下同)左右;Z2CND18-12N在两种溶液中均表现为较大的亚稳态波动后点蚀击穿,Eb在+500mV附近。S32760表现出优秀的点蚀抗力,但在60℃时出现较明显的亚稳态波动;Z2CND18-12N在低温3℃下表现出与S32760接近的点蚀抗力,但是温度升高至30℃和60℃时,点蚀抗力显著下降,出现明显的点蚀坑,点蚀抗力不及S32760的。S32760在3.5%NaCl和10% NaCl中的CPT分别为86℃和79℃,Z2CND18-12N的则为23℃和20℃。
The effects of environmental factors on the pitting behaviors of Z2CND18-12 Naustenitic stainless steel and S32760 duplex stainless steel in simulated seawater environment were investigated by means of potentiodynamic polarization,critical pitting temperature(CPT)measurement and corrosion morphology observation.The results showed that the polarization behaviors of each materials in artificial seawater and 3.5% NaCl solution at 30 ℃ were similar.The pitting potential Ebof S32760 was about+ 1 100 mV(relative to saturated calomel electrode SCE,the same below).Z2CND18-12 N in the two solutions showed apparent metastable fluctuation before the pitting breakdown,with Ebaround +500 mV.S32760 showed excellent pitting resistance,but apparent metastable fluctuation occurred at 60 ℃.Pitting resistance of Z2CND18-12 N was close to that of S32760 at low temperature of3 ℃,but decreased significantly when the temperature increased to 30℃ and 60℃.The pitting corrosion resistance of Z2CND18-12 N was weaker than that of S32760 duplex stainless steel.CPT of S32760 in the 3.5% NaCl and 10% NaCl were 86 ℃ and 79 ℃,with the corresponding values of 23 ℃ and 20 ℃for Z2CND18-12 N.
The effects of environmental factors on the pitting behaviors of Z2CND18-12 Naustenitic stainless steel and S32760 duplex stainless steel in simulated seawater environment were investigated by means of potentiodynamic polarization,critical pitting temperature(CPT)measurement and corrosion morphology observation.The results showed that the polarization behaviors of each materials in artificial seawater and 3.5% NaCl solution at 30 ℃ were similar.The pitting potential Ebof S32760 was about+ 1 100 mV(relative to saturated calomel electrode SCE,the same below).Z2CND18-12 N in the two solutions showed apparent metastable fluctuation before the pitting breakdown,with Ebaround +500 mV.S32760 showed excellent pitting resistance,but apparent metastable fluctuation occurred at 60 ℃.Pitting resistance of Z2CND18-12 N was close to that of S32760 at low temperature of3 ℃,but decreased significantly when the temperature increased to 30℃ and 60℃.The pitting corrosion resistance of Z2CND18-12 N was weaker than that of S32760 duplex stainless steel.CPT of S32760 in the 3.5% NaCl and 10% NaCl were 86 ℃ and 79 ℃,with the corresponding values of 23 ℃ and 20 ℃for Z2CND18-12 N.
引文
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[2]辛森森,李谋成,沈嘉年.海水温度和浓缩度对316L不锈钢点蚀性能的影响[J].金属学报,2014,50(3):373-378.
[3]邓博,蒋益民,龚佳,等.双相不锈钢临界点蚀温度和再钝化温度[J].中国有色金属学报,2007(10):47-53
[4]王威.316L不锈钢点蚀的电化学行为及其影响因素研究[D].成都:西南石油大学,2014.
[5]R.温斯顿.里维,Revie,等.尤利格腐蚀手册[M].北京:化学工业出版社,2005.
[6]孙道明.不锈钢点蚀花边盖脱落与稳定生长[J].郑州大学学报,2009,30(1):70-74.
[7]ELMER J W,PALMER T A,SPECHT E D.In situ observations of sigma phase dissolution in 2205duplex stainless steel using synchrotron X-ray diffraction[J].Material Science and Engineering:A,2007,459:151-155.
[8]何进.超级双相不锈钢S32750钝化膜在海洋环境中的失效行为研究[D].昆明:昆明理工大学,2014.
[9]高丽飞,杜敏.304不锈钢在淡化海水中的点蚀行为[J].腐蚀科学与防护技术,2017,29(1):8-13.
[10]吴玮巍,蒋益民,廖家兴,等.0Cr25Ni7Mo4、316与304不锈钢CPT研究[J].腐蚀科学与防护技术,2006,18(4):285-288.
[11]戴起勋.金属材料学[M].北京:化学工业出版社,2013:123-126,139.