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采用干湿周浸试验、失重法和电化学研究了同一成分不同组织高强耐蚀钢筋在3.5%Na Cl溶液中的腐蚀行为与规律。用数码相机对除锈前后的试样进行宏观观察,用扫描电镜(SEM)对腐蚀产物的形貌与致密性进行观察,用XRD对锈层进行分析。结果表明:由于受组织结构及局部腐蚀的影响,在腐蚀初期,热处理态钢筋的平均腐蚀率明显低于热轧态的。随着腐蚀时间的进一步延长,热处理态钢筋的腐蚀速率先快速增加,然后逐步稳定;因其锈层稳定性较差,热轧态钢筋的腐蚀速率较长时间呈现波动状态,至288 h时锈层才基本稳定。在腐蚀后期,两种钢筋的腐蚀速率基本一致,两种钢筋长期阻抗值基本一致,表明长期腐蚀速率接近,显微组织对耐蚀性能的影响只停留在稳定锈层形成前。
Corrosion behaviors and regularities of high strength and corrosion resistant steel bars with different compositions of the same component in 3.5% NaCl solution were studied by wet-dry immersion test, weight loss test and electrochemical tests. A digital camera was used to observe the samples before and after descaling. The morphology and compactness of the corrosion products were observed by scanning electron microscopy (SEM), and the rust layers were analyzed by XRD. The results show that due to the influence of microstructure and local corrosion, the average corrosion rate of heat-treated steel bars is obviously lower than that of hot-rolled steel bars in the early stage of corrosion. With the further extension of corrosion time, the corrosion rate of heat treated steel rapidly increases first and then gradually stabilizes. Due to the poor stability of the rust layer, the corrosion rate of hot rolled steel shows a fluctuating state for a long time, Stratum basically stable. In the later stage of corrosion, the corrosion rates of the two kinds of steel are basically the same, and the long-term resistance values of the two kinds of steel are basically the same, indicating that the long-term corrosion rate is close to the corrosion resistance of the microstructure only before the formation of the stable rust layer.