氯盐环境下600 MPa级耐蚀钢筋腐蚀行为研究

Study on the corrosion behavior of a 600 MPa corrosion-resistant steel bar in a chloride environment

以普通600 MPa级高强抗震钢筋HRB600E和经过合金调控后的同级别耐蚀钢筋为试验对象,通过周期浸润试验、电化学试验、表面分析技术和物相分析技术研究了氯盐环境下Cr、V对600 MPa级耐蚀钢筋腐蚀行为。结果表明,耐蚀合金的加入促进基体中贝氏体组织产生,减缓了铁素体阳极腐蚀进程;V、Cr元素的协同作用能够阻碍Cl-下渗,有效延缓锈层生长速度,360 h周期浸润后耐蚀钢筋腐蚀速率下降;Cr-V体系元素调控下耐蚀钢筋电化学性质自腐蚀电位提升,钝化后电位正移,腐蚀电流密度下降;耐蚀钢筋钝化后交流阻抗值显著提升,在混凝土碱性环境中耐腐蚀性能优异;合金元素调控改善了钢筋腐蚀产物的物相组成,耐蚀钢筋后期腐蚀产物中α-FeOOH及γ-FeOOH占比更高,且内锈层有尖晶石结构产物FeCr_(2)O_(4)富集,增加了内锈层的致密度和稳定性。

The effect of Cr and V elements on the corrosion behavior of the ordinary 600 MPa grade high-strength seismic steel bar HRB600E and the same grade corrosion-resistant steel bar after alloy regulation was studied by the cyclic immersion tests,electrochemical tests,surface analysis,and phase analysis in a chloride environment.The results show that the addition of corrosion-resistant alloy promotes the formation of bainite in the matrix and slows down the corrosion process of the ferrite anode.The synergistic effect of V and Cr elements can hinder the infiltration of Cl-,effectively delaying the growth rate of the rust layer,and the corrosion rate of corrosion-resistant steel bars decreases after 360hours of cyclic immersion.Under the control of Cr-V elements,the self-corrosion potential of the electrochemical properties of corrosion-resistant steel bars increases,while the potential shifts positively after passivation,and the corrosion current density decreases.The AC impedance value of the corrosionresistant steel bar is significantly improved after passivation,and it shows excellent corrosion resistance in the alkaline environment of concrete.The regulation of alloying elements improves the phase composition of corrosion products of the steel bars.The proportion ofα-FeOOH andγ-FeOOH in the later corrosion products of the corrosion-resistant steel bars is higher and the internal rust layer is enriched with spinel-structured product FeCr_(2)O_4,which increases the density and stability of the internal rust layer.