NaNO_3对含Cl^-衣康酸溶液中316L不锈钢的缓蚀作用

INHIBITION EFFECT OF NaNO_3 FOR 316L STAINLESS STEEL IN Cl- CONTAINING ITACONIC ACID SOLUTIONS

通过失重法和电化学法以及表面膜ＸＰＳ分析，研究了ＮａＮＯ３对含Ｃｌ－衣康酸介质中３１６Ｌ不锈钢的侵蚀性能。结果表明：溶液中一定量的ＮａＮＯ３可使不锈钢的点蚀电位显著提高，有效地抑制点蚀，缓蚀效率达８１～９５％；温度、Ｃｌ－浓度及的存在等因素对缓蚀性能有一定影响；ＮａＮＯ３通过竞争吸附机制起缓蚀作用。

By weight loss and electrochemical measurements and XPS analysis, the inhibition effect of NaNO3for 316L stauiless steel in Cl- containing itaconic acid media was investigated. The results showed that thepitting corrosion of the steel in the media could be prevented effectively in the presence of some amountsof NaNO3, which could raise the critical pitting potential up to the transpassive potential so as to resultin a superior pitting resistance. The inhibition efficiency reached to 80~95% in various solutions at 38C.Some factors, such as temperature, Cl- concentration and the foreign ions,e.g. Fe3+ in solutions, couldaffect the inhibition performance. The competitive adsorption between NO3 and Cl- on the steels surfacemight be a main mechanism for inhibition. In view of the dual functions of NaNO3 as an inhibitor and asa nitrogenous source necessary for the fermentation process, it is feasible for NaNO3 to be recommendedfor use in the production of itaconic acid by fermentation.