针对某厂精对苯二甲酸(PTA)生产装置氧化单元设备的腐蚀问题,在高温高压反应釜中进行了浸泡腐蚀试验,研究了温度对有氧和无氧条件下316L、317L和904L不锈钢在含Br^-醋酸溶液中耐蚀性的影响,采用电化学测试、体视显微镜和扫描电镜等方法,分析了3种材料的电化学特征及表面腐蚀形貌。结果表明:随着温度的升高,3种材料的腐蚀速率均逐渐增大,且其在有氧条件下的腐蚀速率比无氧条件下的大,3种材料的耐蚀性按从高到低的顺序依次为904L不锈钢、317L不锈钢和316L不锈钢;当温度为60℃时,3种材料的腐蚀程度均较轻,其表面均保持金属光泽,无明显腐蚀痕迹;随着温度的继续升高,材料表面的腐蚀程度加剧;当温度低于60℃时,3种材料均发生了点蚀,其点蚀电位按从低到高的顺序依次为316L不锈钢、317L不锈钢和904L不锈钢。

Aiming at the corrosion problem of oxidation unit equipment of purified terephthalic acid (PTA) production unit in a factory, an immersion corrosion test was carried out in a high temperature and high pressure reactor. The effect of temperature on corrosion resistance of 316L, 317L and 904L stainless steels in acetic acid solution containing Br^- under aerobic and anaerobic conditions was investigated. Electrochemical characteristics and surface corrosion morphology of three materials were analyzed by electrochemical test, stereo microscope and scanning electron microscope. The results showed that with the increase of temperature, the corrosion rates of the three materials increased gradually, and their corrosion rates under aerobic condition was higher than those under anaerobic condition. The corrosion resistance of the three materials was 904L stainless steel, 317L stainless steel and 316L stainless steel in order from high to low. When the temperature was 60℃, the corrosion degree of three materials was relatively light, and their surface maintained metallic luster without obvious corrosion marks. As the temperature continued to rise, the corrosion degree of the material surface was aggravated. When the temperature was lower than 60℃, pitting corrosion occurred in all three materials, and their pitting corrosion potentials was 316L stainless steel, 317L stainless steel and 904L stainless steel in order from low to higt.