耐候钢新型表面锈层稳定剂处理及其耐3.5％NaCl溶液周浸腐蚀性能

目的解决耐候钢裸露使用初期锈液流挂与飞散的问题。方法制备了新型耐候钢表面锈层稳定剂,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海洋大气环境下,锈层稳定剂对耐候钢锈层结构及耐腐蚀性能的影响。结果表面锈层稳定化处理后,耐候钢表面生成的锈层区分为致密且连续的内锈层和外锈层。室内加速腐蚀168 h后,耐候钢的失重腐蚀速率由未处理的5.71 g/(m~2×h)降低到表面处理后的3.31 g/(m~2×h),失重腐蚀速率降低了约42%。耐候钢的锈层电阻由未处理的96?·cm~2提高到表面处理后的167.7?·cm~2,锈层电阻提高了约75%。表面处理后的耐候钢锈层中,Cr元素以α-(Fe_(1-x)Cr_x)OOH的形式存在于基体与锈层的界面处,Cr元素在内锈层与基体结合处发生聚集。结论新型锈层稳定剂可以明显改善耐候钢锈层结构,细化锈层晶粒,阻碍Cl~-的渗透,有助于耐候钢表面快速生成致密、连续且稳定的保护性锈层。

A New Rust Stabilization Treatment of Weathering Steel and Its Periodic Immersed Corrosion Resistance in 3.5% NaCl Solution

The work aims to solve sagging and flyoff of rust liquid occurring when bare weathering steel is firstly used.A new rust layer stabilizer was prepared for new weathering steel surface.Effects of rust layer stabilizer on rust layer structure and corrosion resistance of the weathering steel in the stimulated marine atmosphere were investigated by performing periodic immersion cyclic corrosion test,rust microscopic analysis and electrochemical testing.The treated rust layer of weathering steel was divided into compact and continuous inner rust layer and outer rust layer.After 168 h of indoor accelerated corrosion,weight loss corrosion rate of the weathering steel was reduced to 3.31 g/(m2.h) from 5.71 g/(m2.h) (compared to bare surface) by nearly 42％.The rust layer resistance of treatment steel increased up to 167.7 Ω·cm2 from 96 Ω.cm2.The rust layer resistance increased from 96 Ω·cm2 to 167.7 Ω· cm2 by nearly 75％.In the treated rust layer of weathering steel,Cr element was present on the interface between rust layer and substrate in the form of α-(Fe1-xCrx)OOH,and it aggregated in interface between inner rust layer and the substrate.The new rust stabilizer can obviously improve rust structure of the weathering steel,refine rust grain,and hinder permeation of Cl-,which contributes to rapid generation of compact,continuous and stable protective rust layer on surface of weathering steel.