模拟海洋大气环境下Cu和Cr对耐候钢耐腐蚀性能的影响

Influence of Alloying Elements Cu and Cr on the Corrosion Resistance of Weathering Steels in Simulated Ocean Atmospheric Environment

过去,合金元素对耐候钢海洋环境中的耐蚀性影响缺乏详细的论讨。选取Q235和5种不同Cu和Cr含量的耐候钢,在0.5%的NaCl溶液中模拟海洋大气环境进行周期浸润试验。研究结果表明:在Cl-存在的环境中,在碳钢的基础上单独添加Cr(0～3.0%)或单独添加Cu(0.25%～0.50%)都不能使钢的耐蚀性有显著的提高。单独提高耐候钢中Cr的含量,有助于抑制其在腐蚀初期的腐蚀速度,但对后期的腐蚀发展趋势不利;单独提高Cu的含量,有助于延缓腐蚀后期的发展趋势。当同时提高耐候钢中的Cu和Cr含量时,可使耐候钢得到较佳的耐大气腐蚀性能。XRD分析结果表明,合金元素对外锈层的成分影响不大,其主要大气腐蚀产物为γ-FeOOH,Fe3O4,γ-Fe2O3和少量α-FeOOH。

The corrosion behaviors of Q235 and five kinds of weathering steels containing different contents of alloying elements Cu and Cr in simulated ocean atmos-pheric environment were studied using wet-dry cyclic corrosion tests in the solution of 0.5% NaCl.The compositions of the rus-ted layers on the steels were analyzed by means of X-ray diffrac-tion.Results indicated that in Cl-containing environment,the introduction of Cr alone(0-3%)or Cu alone(0.25% ~ 0.50%)led to no significant improvement on the corrosion resist-ance of the steels.Increasing the content of Cr in the steels con-tributed to restrain the corrosion of the steels in the early stage of corrosion but led to damage to the corrosion resistance in a long-run.Contrary to the above,increasing the content of Cu helped to retard the corrosion of the steel at extended corrosion duration.Moreover,it was feasible to significantly improve the corrosion re-sistance of the weathering steels simultaneously increasing the contents of alloying elements Cu and Cr,but the alloying ele-ments had little effects on the compositions of the top rusted lay-ers.And the corrosion products were composed of γ-FeOOH,Fe3O4,γ-Fe2O3,and a small amount of α-FeOOH.