Na_2SO_4液膜下碳钢早期腐蚀速率及其环境因素的关联性  

ENVIRONMENTAL FACTORS CONTROLLING EARLY CORROSION PERFORMANCE OF CARBON STEEL UNDER LIQUID LAYER CONTAINING SO_4^(2-)

作　　者：唐子龙[1,2] 李辉[1] 李超[1] 

机构地区：[1]天津大学材料科学与工程学院,天津300072 [2]天津大学天津市材料复合与功能化重点实验室,天津300072

出　　处：《中国腐蚀与防护学报》2010年第3期217-221,共5页Journal of Chinese Society For Corrosion and Protection

基　　金：国家自然科学基金项目(50671072);科技部专项课题(2005DKA10400-Z4)资助

摘　　要：采用磁阻探头技术研究10 mmol/L Na_2SO_4液膜下碳钢的腐蚀行为,计算了潮湿时间内的平均腐蚀速率(IFACR)。基于多因素关联的数据标准化方案,采用线性模型分析平均腐蚀速率随浸润时间(TOI)、温度和相对湿度(RH)的变化关系。同时用电化学方法测试了Q235钢在10 mmol/L Na_2SO_4溶液中的腐蚀行为,计算得到自腐蚀电流和极化阻力等电化学参数以辅助IFACR的分析。结果表明,TOI和RH跟IFACR呈负相关,温度与IFACR呈正相关。温度24℃和RH=70%左右是平均腐蚀速率变化的转折点。讨论了转折点附近的平均腐蚀速率及其受温度和RH影响权重的变化。TOI对潮湿期平均腐蚀速率的影响最小,温度和湿度影响IFACR的模式以及相对重要性跟TOI有关。污染离子浓缩对潮湿过程平均腐蚀速率和腐蚀总量有重要贡献。Corrosion performance of carbon steel under 10 mmol/L Na_2SO_4 liquid layer is investigated by inductive resistance probe（IRP）and electrochemistry techniques.Average corrosion rate in wet period, named by IFACR,is calculated based on integration filter algorithm（IFA）with controlled environment factors including time of immersion（TOI）,temperature and relative humidity（RH）.A data-standardization approach is proposed in order to improve the accuracy of IFACR correlation with the control factors modeled by a linear equation.Two sets of corrosion kinetics parameters,corrosion current density I_（corr）,polarization resistance R_p and corrosion rate,of Q235 steel in 10 mmol/L Na_2SO_4 is measured by dynamic potential scan and potential step with an intension to benefit the understanding of corrosion under thin liquid layer.The results indicate that temperature has positive influence on IFACR,while TOI and RH show negative correlation with IFACR. A changed contribution of the factors to IFACR is specified around 24℃and RH=70%called threshold.This threshold is consistent with that from previous TOW（Time of wetness）measurements.The contribution of TOI to IFACR is minor.However,the domination of temperature and RH on IFACR is strongly dependent on TOI.A detailed discussion on the dependence of IFACR and total corrosion loss on TOI,temperatures and RH is presented with the help of electrochemical measurements.

关 键 词：大气腐蚀 薄液膜 数据标准化 原位测量 关联性 

分 类 号：TG142[一般工业技术—材料科学与工程] TG172[金属学及工艺—金属材料]