316L不锈钢楔形缝隙内溶液化学

Solution Chemistry in Cuneiform Crevice of 316L Stainless Seel

摘要: 用微电极研究了316L不锈钢楔形缝隙在3.5%NaCl溶液(室温)中的溶液化学变化规律。结果表明:在两种不同缝隙开口情况下,缝隙内各点的Cl^-都发生了富集,pH也都降低;当缝隙开口为1.36mm时,缝隙内Cl^-浓度随时间和与缝口距离的增大而增大,pH值随之下降,最高Cl^-浓度为1.6mol/l,最低pH值为5.01;当缝隙开口为0.22mm,最高Cl^-浓度为1.1mol/l,最低pH值为3.1.缝隙内溶液酸化是由于金属离子的水解和Cl^-的共同作用,缝内金属氯化物浓度甚至可以达到饱和态。

Abstract: The solution chemistry in cuneiform crevice of 316L stainless steel was studied in 3.5%NaCl at room temperature.The Cl^-was concentrated and PH value decreased in the cuneiform crevice with two sizes of crevice opening. When the crevice opening is 1.36mm,the Cl^-concentration increased and PH value decreased with time and the distrance from the opening. The highest Cl^-concentration is 1.6mol/l and the lowest PH value is 5.01.When the opening is 0.22mm, the highest Cl^- is 1.1 mol/l and the lowest PH value is 3.1.The very low PH value in the crevice was formed by the hydrolysis of dissolving metal ions and Cl^-. The chloride can be very concentrated in the crevice. even be saturated.