钙处理对桥梁钢耐大气腐蚀性能的影响

以NaCl+NaHSO₃溶液为腐蚀介质，采用干/湿周浸加速腐蚀实验、失重分析、XRD、SEM和电化学方法，研究了钙(Ca)处理对桥梁钢在湿热工业-海洋大气中腐蚀行为的影响. 结果表明：Ca处理前后，实验钢的腐蚀深度随时间变化曲线总体符合幂函数W=Atn分布规律，锈层主要由非晶物质和少量晶体α-FeOOH、β-FeOOH、γ-FeOOH、Fe₃O₄组成. 微量Ca能促进铁素体生成、强化钢表面保护膜，以阻止裸钢的快速腐蚀；还能细化钢组织晶粒、抑制腐蚀产物的晶体转变，以细化锈层颗粒、减少锈层缺陷产生，进而改善锈层的致密性.

Effect of Calcium on Atmospheric Corrosion Resistance of Bridge Steel

The corrosion behavior of bridge steel in simulated hot and humid industrial-marine atmosphere was investigated by mass loss analysis, XRD, SEM, electrochemical methods and a wet/dry alternate immersion corrosion test using 0.1 mol•L^-1 NaCl+0.01mol•L^-1 NaHSO₃ solutions. The corrosion depth (W) of experimental steels before and after calcium treatment versus time (t) curves showed a good agreement with the power function of W=Atⁿ. The corrosion products were mainly composed of amorphous phase and a small amount of crystals including α-FeOOH, β-FeOOH, γ-FeOOH and Fe₃O₄. Trace calcium could promote the formation of ferrite and strengthen the protective film on steel surface to prevent the rapid corrosion of bare steel. It could also refine the grain of steel structure and inhibit the crystal transformation of corrosion products, accordingly, refine the particles of corrosion products and reduce the defects in rust layer, and finally, improve the density of rust layer.