NaCl污染的A3钢在含SO_2的大气环境中的腐蚀

ATMOSPHERIC CORROSION OF NaCl CONTAMINATED A3 STEEL IN AIR CONTAINNG SO_2

分别对温度为 2 5℃、相对湿度为 75 %条件下未经NaCl污染和表面沉积有 15 .6 μg/cm2 NaCl的A3钢在含有 10 -6SO2 大气环境中的腐蚀行为进行了研究 .结果表明 ,NaCl和SO2 的共同作用导致腐蚀加剧 ,但随暴露时间的延长 ,后期腐蚀速度有明显减弱 .采用扫描电镜 (SEM/EDAX)和傅立叶变换红外光谱 (FTIR)对腐蚀表面和产物进行了分析 .腐蚀表面呈现不均匀的凹凸形貌 ,腐蚀产物膜上有细微裂缝 ,这为后期腐蚀氧的扩散提供了通道 .腐蚀产物中有FeSO4·7H2

Atmospheric corrosion of A3 steel without and with NaCl pre-deposit in air containing 10 -6 SO 2 at 25℃ and 75%RH was studied in this paper. The relationship between metal loss and exposure time was described in detail. The results obtained showed that the combined effect of NaCl and SO 2 could accelerate the corrosion of A3 steel and that the corrosion rate in later stage slowed down with exposure time.SEM/EDAX and FTIR spectroscopy were used to analyze the corrosded surface and corrosion products. The surfaces were obviously uneven, and some tiny crevices appeared in rust layers that can help O 2 diffuse to inner layer. FeSO 4·7H 2O and FeOOH were identified in the corrosion products.