激光表面重熔提高2Cr13钝化膜的稳定性

THE IMPROVEMENT OF PASSIVE FILM STABILITY OF 2Cr13 STEEL BY USING LASER SURFACE REMELTING

一、前言激光表面重熔是近年发展起来的一种改善材料耐蚀性的表面改性技术。McCafferty等和Lumsden等的研究表明,经激光重熔处理后304不锈钢的耐蚀性能,在含c1^-介质中超过316不锈钢。王茂才等对M38镍基超合金的研究工作表明,激光重熔处理由于改变了第二相分布,使耐蚀性成倍提高。 2Cr13马氏体不锈钢具有较高的强度和较好的机械性能,但其耐蚀性能远不及0Cr18Ni9等奥氏体不锈钢。本工作通过激光重熔处理对2Cr13进行表面改性,试图改善2Cr13的钝化特性和钝化膜的稳定性。

Laser remelting treatment was done on the surface of 2Cr13 stainless steel by 2kW CO_2 laser with continuous wave. The passive characteristics and the stability of passive films of treaed area were determined respectively in 0.5 mol/L H_2SO_4 and 0.5mol/L H_2SO_4+0.3mol/L NaCl by means of potentiostatic-galvanostatic transient technique and other electrochemical measurement methods. The microstructure and surface morphology at laser remelting area were observed by scanning electron microscope (SEM). The results indicated that laser remelting treatment improved the passive performance of 2Cr13 and that its stability and pitting resistance of passive films were promoted a lot. The corrosion characteristic of treated area is comparable to that of 0Cr18Ni9 austenitic stainless steel. The corrosion resistance mechanism was discussed preliminarily.