电化学方法研究混凝土模拟液中细晶粒钢的耐蚀性

Corrosion resistance of fine-grained rebar in simulated concrete pore solutions by means of electrochemical methods

通过腐蚀电位、线性极化法与循环极化法等电化学方法研究了细晶粒钢和普通低碳钢在模拟混凝土孔溶液中的均匀腐蚀与点蚀行为,并考虑了砂磨和未处理两种钢筋表面状况对钢筋腐蚀行为的影响.结果表明,细晶粒钢与普通低碳钢在模拟液中的耐均匀腐蚀的能力很接近;砂磨钢筋的钝化效果比未处理钢筋好;腐蚀末期砂磨钢筋表现出比未处理钢筋更强的抑制均匀腐蚀能力.循环极化测试表明:砂磨钢筋由于其相对均匀的表面组织形貌,故表现出比未处理钢筋更好的抑制点蚀能力;其次,由于细晶粒钢含有较多晶界,晶界处含有较多易发生点蚀的夹杂,故表面未处理细晶粒钢发生点蚀的概率稍大于未处理低碳钢.

Uniform and pitting corrosion behaviors of fine-grained rebar and low-carbon rebar in simulated concrete pore（SCP） solutions were investigated by means of corrosion potential,linear polarization resistance（LPR） and cyclic polarization.The influence of two different rebar surface conditions,i.e.,sandblasted and as-received,on the corrosion behavior of the rebar was taken into consideration.The results indicate that fine-grained rebar and low-carbon rebar show almost the same uniform corrosion behavior,and the passivation effects are better for sandblasted rebar than as-received rebar.In the latter period of corrosion,sandblasted rebar shows a higher uniform corrosion resistance than as-received rebar.Cyclic polarization measurements reveal that sandblasted rebar performs better in delaying pitting corrosion due to the relatively homogeneous surface than as-received rebar.Since more impurity-containing grain boundaries in fine-grained rebar facilitate the occurrence of pitting corrosion,the probability of pitting corrosion for as-received fine-grained rebar is slightly higher than that of as-received low-carbon rebar.