Fe-Cr-Ni合金碱性SCC的电化学预测方法  

An Electrochemical Prediction Method for Caustic SCC of Fe-Cr-Ni Alloy

作　　者：黄春波[1] 吕战鹏[1] 杨武[1] 

机构地区：[1]上海材料研究所,上海200437

出　　处：《电化学》2003年第3期292-298,共7页Journal of Electrochemistry

基　　金：国家重点基础研究专项 (G1 9990 6 5 0 ) ;科技部科研院所社会公益专项 ;上海市青年科技启明星项目(0 0QE1 4 0 2 1 )资助

摘　　要：应用动电位扫描研究了Fe_Cr_Ni合金 (80 0M)C形环在含硫代硫酸钠杂质的热浓碱溶液中的应力腐蚀破裂 (SCC)行为 .测量了 80 0M合金试片与C形环试样恒电位极化时的稳态溶解电流ist,据此绘制了简化模拟“稳态”恒电位极化曲线 ,并将该极化曲线的ist与低电位下的稳态钝化电流ip之比 (RPD=ist/ip)定义为极化溶解敏感指数 .发现 80 0M合金C形环发生碱性SCC的电位区 (E =- 30～ 4 0mV)处于慢扫阳极极化曲线的钝化区 ,并对应于快扫极化曲线的钝化_过钝化溶解转变区 ;在该敏感电位区 ,试片与C环形试样的ist位于简化的模拟稳态恒电位极化曲线的过钝化区 ,试片与C形环试样两者的极化溶解敏感指数值很接近 (分别为 2 .5 5～ 7.0 3和 2 .5 2～ 6 .0 0 ) .综合稳态溶解电流密度 ,极化溶解敏感指数等有关信息 。Stress corrosion cracking (SCC) of Fe_Cr_Ni alloy (alloy 800 M) in hot concentrated caustic solution was investigated by means of tests of C_rings under controlled potentials. The steady dissolution current densities( i st ) of the plate specimens and C_rings polarized potentiostatically were measured. The simplifed steady potentiostatical curves were drawn on the basis of i st . The ratio R PD measured from i st and steady passive current density i p at low potentials ( R PD = i st / i p ) was designed as a polarization dissolution susceptibility parameter. The parameter R PD values of both plate and C_ring specimens were similar to SCC sensetive potentials of C_rings between-30 mV/SCE and 40 mV/SCE. An Electrochemical prediction method for caustic SCC was proposed basd on the electrochemical characters synthesizing i st and R PD .

关 键 词：FE-CR-NI合金 碱性SCC 电化学预测 稳态溶解电流密度 极化溶解敏感指数 材料 应力腐蚀破裂 

分 类 号：TG174.32[金属学及工艺—金属表面处理]