Development of Corrosion Resistant Alloys for Municipal Waste Incinerators

在723~873K温度范围内，对18种工业合金和13种实验室熔炼合金在3种不同熔盐中的腐蚀性能进行了评价，以选择适用于城市垃圾焚烧环境的材料。该评估是使用交流阻抗筛选测试进行的，该测试是本研究中开发的一种快速评估热腐蚀的工具。在每个熔体中选出最有希望的候选合金，然后在传统的盐涂层测试中进行评估。通过对31种合金在硫酸盐、氯化物和氯化物/硫酸盐环境中的交流阻抗腐蚀筛选试验和盐膜试验，得出以下结果：1.在含氯环境中，高铬、高钼合金表现出良好的腐蚀性能，而在硫酸盐环境中，高铬、高钼合金表现出良好的腐蚀性能。在模拟的垃圾焚烧环境中，625合金和C-22合金被选为最优良的耐蚀材料。3.耐蚀性差的合金随着硫酸盐和氯化物熔体中水分含量的增加，腐蚀速度都有加快的趋势。同时，水含量的增加似乎降低了硫酸盐/氯化物熔体中的腐蚀速率。总体而言，水含量的变化对合金在所用熔体中的腐蚀性能排名没有显著影响。4.交流阻抗测试结果与常规盐涂层测试结果一致。本研究开发的电化学筛选测试系统是一种非常有用的熔盐腐蚀快速评价方法。

Corrosion performance of eighteen commercial and thirteen lab-melted alloys have been evaluated in three different molten salts in the temperature range 723 to 873K in order to select materials to be employed in municipal waste incinerator environments. The evaluation was performed using an AC impedance screening test which was developed in this study as an instrument for rapid evaluation of hot corrosion. The most promising candidate alloys have been selected in each melt, and subsequently evaluated in a conventional salt coating test. The corrosion data obtained in AC impedance screening tests has been analyzed by a multiple linear regression method in order to clarify the effect of alloy elements on the corrosion performance.From the AC impedance corrosion screening test and salt coating tests of thirty one alloys in the sulfate, the chloride and the chloride/sulfate environments, the following results were drawn :1.In the chloride containing environments, high Cr and high Mo alloys indicated excellent corrosion performance, while in the sulfate environment, high Cr and Mo-free alloys showed excellent corrosion resistance.2.Alloy 625 and Alloy C-22 were selected as most excellent corrosion resistant materials in the simulated municipal waste incinerator environments.3.Poor corrosion resistant alloys tend to show an acceleration of corrosion rate with an increase in water content in both the sulfate and chloride melts. Meanwhile, it seems that an increase of water content reduced the corrosion rates in the sulfate/chloride melt. In general, a change in the water content provided no significant difference in the rankings of corrosion performance of the alloys in the employed melts.4.The results obtained from AC impedance testing were in good agreement with those from conventional salt coating test. The electrochemical screening test system developed in this study was found to be very useful as a rapid evaluation method for molten salt corrosions.