材料期刊网

目的：地热水的腐蚀和结垢是地热资源开发利用的核心问题,研究几种常见金属材料在地热水中的腐蚀和结垢规律,为地热资源开发利用提供理论依据。方法通过扫描电子显微镜,X射线衍射仪、动态挂片试验、极化和交流阻抗测试等方法,对比研究紫铜、304不锈钢和20#碳钢在模拟地热水溶液中的腐蚀和结垢情况。结果3种金属材料表面的结垢产物均为CaCO3,20#碳钢表面的CaCO3均为方解石相,304不锈钢和紫铜表面的CaCO3包含方解石相和少量文石相,304不锈钢表面的CaCO3分布较紫铜疏松,且含垢量较小。20#碳钢表面腐蚀产物的内层主要是黑色的Fe3 O4,外层主要是黄色的Fe2 O3；紫铜表面的腐蚀产物主要是铜的氧化物；304不锈钢表面无腐蚀产物。浸泡期间,304不锈钢未发生腐蚀且腐蚀电流密度最小；紫铜的整体耐蚀性能不及304不锈钢,但耐点蚀性能最佳；20#碳钢腐蚀严重,腐蚀电流密度较大。结论在模拟地热水溶液中,304不锈钢拥有比紫铜和20#碳钢更好的耐腐蚀性能和阻垢性能。

ABSTRACT:Objective Corrosion and scaling are the main problems in the development and utilization of geothermal resources. The aim of this work was to study the scaling and corrosion rules of common metal materials in geothermal water, and to provide theoretical basis for the development and utilization of geothermal resources. Methods Scanning electron microscopy, X-ray diffrac-tion, immersion corrosion and electrochemistry test were used to study and compare the scaling and corrosion rules of copper pipes, 304 stainless steel pipes and 20# carbon steel pipes in a simulated geothermal water environment. Results The scaling product of three kinds of metal materials was CaCO3, but with different phases. The CaCO3 on the surface of 20# carbon steel pipes showed only calcite phase, while the CaCO3 on the surface of copper and 304 stainless steel pipes showed a small amount of aragonite phase besides calcite phase. And the 304 stainless carbon steel pipes had the minimum amount of scaling, and the distribution of CaCO3 was not as dense as that on copper. A large amount of corrosion products were formed on the surface of 20# carbon steel pipes. The inner layer was mainly Fe3 O4 , and the outer layer was Fe2 O3 . The corrosion products of copper pipes were mainly copper oxides. While no corrosion product was formed on the surface of the 304 stainless steel pipes. During the soaking, 304 stainless steel was not corroded and had the lowest corrosion current density. The corrosion resistance of the copper pipes was not as good as that of 304 stainless steel, but its pitting resistance was the best. The 20# carbon steel pipes were severely corroded and had relatively high corrosion current density. Conclusion 304 stainless steel pipes showed better corrosion resistance and anti-scaling performance than cooper pipes and 20# carbon steel pipes in a simulated geothermal water environment.