摘要
利用等通道转角挤压(ECAP)方法,制备出平均晶粒尺寸为(130±30)nm的块体超细晶304L不锈钢.在0.05 mol/L H_2SO_4+0.25 mol/L Na_2SO_4溶液中测量了其极化曲线和钝化性能的Mott-Schottky曲线.结果表明,与粗晶合金相比,超细晶材料的自腐蚀电位更低,自腐蚀电流密度更大,更易发生活性溶解且溶解速度更快,但致钝电位更低,维钝电流密度更小,钝化区间更宽.表面钝化膜均具有n型半导体特征,超细晶粒有助于304L不锈钢表面形成更为稳定的钝化膜,载流子密度更小,载流子的扩散系数更低.
Samples of ultrafine-grained 304L stainless steel with an average grain size of （130± 30） nm were prepared by using equal channel angular pressing （ECAP） technique after 6 passes with route Bc at 500 ℃. The electrochemical behaviors and the passive properties of the material in 0.05 mol/L H2SO4＋0.25 mol/L Na2SO4 solution were examined by using polarization curves and Mott-Schottky analysis. As compared with the coarse-grained counterpart, the ultrafine-grained 304L stainless steel sample exhibits a lower corrosion potential （-505 mV） and a higher corrosion current density （11.7 μA/cm^2）, indicating the accelerated trend of the active dissolution, and has a broadening of passive region （-341-847 mV） with lower passive potential （-341 mV） and passivation current density （4.5 μA/cm^2）. Both of the passive films exhibit n-type semi-conductor behaviors at potentials ranging from 0 to 0.7 V. The ultrafine grains of 304L stainless steel are helpful in forming more stable passive films with the reduced donor density and the diffusion coefficient of the charge carrier.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第3期265-270,共6页
Acta Metallurgica Sinica
基金
辽宁省自然科学基金项目201202127
辽宁省高等学校杰出青年学者成长计划项目LJQ2011033资助~~
关键词
304L不锈钢
超细晶
耐蚀性能
钝化
等通道转角挤压
304L stainless steel, ultrafine grain, corrosion resistance, passivation, equal channel angular pressing （ECAP）
