一种Cr-Ni合金化耐蚀钢筋在氯盐环境中的腐蚀行为

摘要

The corrosion resistance of a Cr-Ni alloyed corrosion resistant rebar and an ordinary rebar HRB400 was investigated by accelerated corrosion testing (salt-spray,alternate immersion) and electrochemical measurement in chloride environment.The corrosion rust layers were analyzed by scanning electron microscopy (SEM),electron microprobe analysis (EMPA) and X-ray diffraction (XRD).The results show that the alloyed corrosion resistant rebar had superior corrosion resistance to Cl-in alkaline and neutral NaCl solutions.The corrosion rates of the alloyed corrosion resistant rebar in salt-spray corrosion test and alternate immersion test were 19.4％ and 12.3％ of those of HRB400 rebar,respectively.The rust layer of HRB400 was thick and loose,its major components were Fe3 O4,α-FeOOH and β-FeOOH.The rust layer of alloyed corrosion resistant rebar were thin and dense relatively,and its major components were Fe3O4,α-FeOOH,β-FeOOH,γ-FeOOH,CrOOH and α-Fe2O3.The structures and types of rust layers were changed by adding Cr,Ni alloy elements and the corrosion resistance of steel bar in chloride environment was greatly improved by the way of reducing the corrosion sensitivity as well as improving the corrosion potential.%通过加速腐蚀试验(盐雾和周浸)、电化学试验等方法研究了一种Cr-Ni合金化耐蚀钢筋和普通钢筋HRB400在氯盐环境中的耐蚀性,并通过扫描电镜(SEM)、电子显微探针分析(EMPA)和X射线衍射(XRD)等技术手段分析了锈层的形貌和组成.结果表明:在碱性和中性NaCl溶液中合金化耐蚀钢筋的耐氯离子腐蚀能力较好;在盐雾、周浸腐蚀试验中的腐蚀速率分别为普通钢筋的19.4％和12.3％;普通钢筋加速腐蚀后的锈层较厚,且为单层疏松结构,其锈层主要由Fe3O4、α-FeOOH和β-FeOOH构成;而Cr-Ni合金化耐蚀钢筋的锈层相对较薄,为多层致密结构,主要组成为Fe3O4、α-FeOOH、β-FeOOH、γ-FeOOH、CrOOH和α-Fe2 O3;合金元素Cr和Ni通过提高钢筋的自腐蚀电位,降低腐蚀敏感性,促进保护性锈层的产生,提高了钢筋在氯盐环境中的耐蚀性.