采用失重法和电化学方法研究了碳钢、321奥氏体不锈钢和2205双相钢在5 000 mg/L NH4Cl溶液以及吸湿NH4Cl环境中的腐蚀行为。结果表明, 两种环境中碳钢表现为均匀腐蚀;吸湿NH4Cl盐的垢下腐蚀比NH4Cl水溶液严重, 且温度升高腐蚀加剧, 在60 ℃时碳钢在吸湿NH4Cl盐中的腐蚀速率高达6.27 mm/a; 321不锈钢的均匀腐蚀速率很低, 但表面均有大量蚀斑和蚀孔, 且在5 000 mg/L NH4Cl溶液中未出现钝化区。2205双相钢的耐点蚀性能显著优于321奥氏体不锈钢, 整个试样表面基本未腐蚀, 但有少数大而深的蚀孔, 随着温度的升高腐蚀加剧, 且两种情况下都发现被腐蚀区域镍含量缺失, 奥氏体相优先被腐蚀, 因此即使是2205双相钢也不能耐受如此高浓度的铵盐。

The corrosion behaviors of carbon steel, 321 austenitic stainless steel and 2205 dual phase steel in 5 000 mg/L NH4Cl solution and wet NH4Cl environment were studied. The results showed that in this two kinds of circumstances, carbon steel presented uniform corrosion, ammonium salt deposit corrosion was more serious than the corrosion of aqueous solution. The corrosion intensified with the increase of temperature, the corrosion rate of carbon steel in wet NH4Cl salt at 60 ℃ reached 6.27 mm/a.The uniform corrosion rate of 321 stainless steel was very low, but there were a large number of plaques and corrosion pits on the surface, and no passivation area in the 5 000 mg/L NH4Cl solution. The pitting corrosion resistance of 2205 dual phase steel is superior to that of 321 austenitic stainless steel. The sample surface of 2205 dual phase steel almost was not corroded, but there were a few big and deep pits. The corrosion intensified with the increase of temperature, and there was no Ni content in corroded areas in this two cases, austenite phase was corroded firstly.