耐候钢表面锈层稳定化处理技术研究

目的解决耐候钢裸露使用初期锈液流失导致污染环境的问题。方法制备了耐候钢表面锈层稳定化处理溶液。通过周期浸润循环腐蚀试验、锈层微观分析和电化学测试等方法,研究了在模拟工业大气环境下,表面处理溶液对耐候钢锈层结构及耐腐蚀性能的影响。结果表面处理后,耐候钢的开路电位由处理前的-0.395 V降低到-0.475 V,表面快速生成一层连续致密的氧化层。加速腐蚀16 d后,耐候钢的腐蚀速率由未处理时的0.209 mg/(cm^2·d)降低到表面处理后的0.106 mg/(cm^2·d),降低了约49%;锈层的自腐蚀电位由未处理的-0.216 V提高到处理后的-0.073 V,提高了约66%,自腐蚀电流密度由未处理时的7.41μA/cm^2降低到1.58μA/cm^2,降低了约79%。随着腐蚀时间从1 d延长至16 d,处理后的耐候钢锈层中α-FeOOH的质量分数由2.96%增加到4.46%,增加了51%,γ-FeOOH的质量分数由2.06%降低到1.65%。表面处理后的耐候钢锈层中,Cu和Cr元素在锈层与基体结合处和锈层内部发生富集。结论处理溶液降低了耐候钢表面的开路电位,可使耐候钢快速生成致密且连续的锈层,锈层中Cu、Cr元素富集促进了γ-FeOOH向α-FeOOH的转化,提高了锈层电化学保护性能,降低了后期腐蚀速率,缩短了稳定化进程。

Rust Stabilization Treatment of Weathering Steel Surface

The work aims to solve the problem of environmental pollution caused by erosion of rust liquid at the initial stage of bare use of weathering steel.A new rust stabilization treatment solution for weathering steel surface was prepared.The effect of surface treatment solution on the rust structure and anticorrosion of weathering steel in the stimulated industrial atmosphere was investigated through periodic immersed corrosion test,rust microscopic analysis and electrochemical measurement.The open circuit potential of weathering steel was reduced from-0.395 V to-0.475 V after surface treatment.There was a continuous oxide layer formed on the surface of steel.After 16 days of corrosion,compared to bare steel,the corrosion rate of weathering steel after surface treatment was reduced from 0.209 mg/(cm^2·d)to 0.106 mg/(cm^2·d).The corrosion rate was reduced by 49%.The potential of rust layer was increased from-0.216 V to-0.073 V after surface treatment and increased by 66%.The current density was reduced from 7.41μA/cm^2 to 1.58μA/cm^2 and reduced by 79%.The content ofα-FeOOH in rust layer after treatment was increased from 2.96%to 4.46%and increased by 51%.On the contrary,the content ofγ-FeOOH was reduced from 2.06%to 1.65%.After surface treatment,Cu and Cr elements were aggregated at the juncture between the rust layer and the substrate and in the rust layer.Thus,the treatment solution reduces the OCP and rapidly forms a continuous rust layer on the surface of weathering steel.Enrichment of Cu and Cr elements in the rust promotes the conversion ofγ-FeOOH toα-FeOOH and increases the electrochemical protection property of rust layer,which improves the electrochemical protection of rust layer,reduces the corrosion rate and shortens the stabilization process.