哌啶缓蚀作用的原子吸收光谱研究——Ⅰ.304不锈钢、工业纯铁、铬、镍在盐酸中的腐蚀行为及哌啶的缓蚀作用

采用原子吸收光谱(AAS),恒电位下电流～时间关系和极化曲线测试等方法研究了304不锈钢、纯铁、铬和镍四种材料在0.1mol/L HCl中的腐蚀行为及哌啶(PD)的缓蚀作用。结果表明:PD可有效地抑制304不锈钢在盐酸中的腐蚀。PD增强Cr在盐酸中的钝化性能,对铁、镍的腐蚀属阴极型缓蚀剂。AAS测试结果表明,304不锈钢的组分元素Fe、Cr、Ni和Mn在盐酸中分别以 2, 3, 2和 2价离子形式溶解,价态不受缓蚀剂的影响。PD对304不锈钢在盐酸中的腐蚀存在“选择性抑制”效应,能显著减缓Cr和Ni的溶解,改变各元素溶解的比例,导致耐蚀组分在电极表面富集。

STUDY ON INHIBITION BY PIPERIDINE USING ATOMIC ABSORPTION SPECTROMETRY I. CORROSION BEHAVIOR OF TYPE 304 STAINLESS STEEL IN HYDROCHLORIC ACID AND ITS INHIBITION BY PIPERIDINE

The corrosion behavior of type 304 stainless steel and industrially pure iron, chromium, nickel in 1.0mol/L HC1 and their corrosion inhibition by piperidine (PD) were investigated by atomic absorption spectrometry (AAS), current vs time relation at constant potential and polarization curve measurements. The results showed that the dissolution of 304 stainless steel in HC1 could be inhibited effectively by PD. The passive range of Cr in HC1 would extend in the presence of PD. For Fe, PD acted as a cathodically controlled inhibitor. A new idea "selective inhibition" was suggested and applied to describe the inhibition by PD for 304 stainless steel in HC1. In the presence of PD , the dissolution rates of Cr and Ni in 304 matrix decreased obviously, and the molar percentages by which various components in 304 stainless steel dissolved were different from those in the absence of PD. AAS data indicated that regardless of the presence of PD the dissolution of Fe, Ni and Mn took the form of divalence, while Cr dissolved in the form of trivalence.