土建工程支架用螺纹钢表面处理及耐腐蚀性能研究

Study on Surface Treatment and Corrosion Resistance of Rebar Used for Supports in Civil Engineering

为有效提高土建工程支架常用的HRB335螺纹钢的耐腐蚀性能,采用复合磷化工艺进行表面处理,然后采用不同封闭方法后处理。实验结果表明:复合磷化螺纹钢的耐腐蚀性能优于常规磷化螺纹钢。复合磷化膜中含有呈良好分散状态的PTFE颗粒起到物理填充作用,可以阻挡腐蚀介质渗透,抑制腐蚀发展。通过浸油封闭和硅酸盐封闭使复合磷化膜的耐腐蚀性能进一步提高,硅酸盐封闭过程中由于溶解作用、析出硅酸钠固体相以及反应生成新硅酸盐化合物,使复合磷化膜的致密性明显改善,具有更好的耐腐蚀性能。复合磷化然后硅酸盐封闭处理的螺纹钢表现出优异的耐腐蚀性能,有望较好的满足使用要求。

HRB335 rebar has been widely used in the manufacturing of supports in civil engineering. In this study,HRB335 rebar was exposed to surface treatment by composite phosphating process,followed by post-treatment via different sealing methods,to improve its corrosion resistance. The results show that the composite phosphated rebar is superior to conventional phosphated rebar in terms of corrosion resistance. The composite phosphating film contains well-dispersed PTFE particles filling intercrystal gap,which hinder the penetration of corrosive media and inhibit the corrosion. The corrosion resistance of composite phosphating film was further improved by oil-immersion sealing and silicate sealing. Due to the dissolution,sodium silicate in the solid-phase precipitates and new silicate compounds were generated by chemical reactions during silicate sealing. As a result,surface defects in the composite phosphating film were repaired,significantly enhancing its compactness and corrosion resistance.The rebar treated by composite phosphating and silicate sealing exhibited excellent corrosion resistance,and it is expected to meet the increasing application requirements.