钛合金缝隙腐蚀、离子渗氮与表面纳米化的研究进展  

Research Progress on Crevice Corrosion, Plasma Nitriding and Surface Nanocrystallization of Titanium Alloys

作　　者：张乘玮 付天琳 陈涵悦 高岩[1] ZHANG Cheng-wei;FU Tian-lin;CHEN Han-yue;GAO Yan(School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]华南理工大学材料科学与工程学院

出　　处：《表面技术》2019年第11期114-123,共10页Surface Technology

基　　金：国家自然科学基金项目(51871099)~~

摘　　要：钛合金凭借优异的耐腐蚀性能,在海洋工程中有着巨大的应用前景,但是其在苛刻条件下易发生缝隙腐蚀及耐磨性差等缺点也影响了它的使用。总结了钛合金发生缝隙腐蚀的条件与原因,以及普通离子渗氮对钛合金耐磨性和耐腐蚀性能的影响,并重点探讨了表面纳米化对钛合金离子渗氮层结合力和耐蚀性能的影响。研究发现,钛合金在高温(65℃以上)、高酸性(低pH值)、高Cl^-浓度、低氧含量的苛刻环境中会发生缝隙腐蚀,氧浓差电池与自催化酸化作用是钛合金缝隙腐蚀的主要机理,钛吸氢形成的脆性TiH2则会加速缝隙腐蚀过程。普通离子渗氮在钛合金表面形成的高硬度TiN、Ti2N层可以提高钛合金的耐磨性,同时提高其耐均匀腐蚀性能。但是,由于离子渗氮层与钛合金基体的硬度差别较大,结合力不强,腐蚀过程中容易发生脱落。利用表面纳米化技术制备表面梯度纳米晶结构,有望通过离子渗氮获得结合力好的渗氮层结构,并可以有效降低渗氮温度。Titanium alloys have great application prospects in marine engineering due to their excellent corrosion resistance, but the disadvantages such as poor wear resistance and crevice corrosion under severe conditions also affect their application. The work summarized the conditions and causes of crevice corrosion of titanium alloys and the effects of normal plasma nitriding on their wear resistance and corrosion resistance and mainly discussed the effects of surface nanocrystallization on corrosion resistance and adhesion of plasma nitriding of titanium alloys. It was found that the crevice corrosion of titanium alloys occurred in a harsh environment of high temperature(above 65 ℃), high acidity(low pH), high Cl^-concentration and low oxygen concentration. Oxygen concentration cell and self-catalytic acidification were the main mechanisms for the crevice corrosion of titanium alloys, and the formation of brittle TiH2 by hydrogen absorption accelerated the process of crevice corrosion. The TiN and Ti2 N layers with high hardness formed by normal plasma nitriding on the surface of titanium alloys could improve their wear resistance and uniform corrosion resistance. However, the large hardness difference between nitriding layer and titanium matrix lead to a weak bonding force, and the nitriding layer was easy to exfoliate during corrosion process. The surface gradient nanocrystalline structure prepared by surface nanocrystallization technology is expected to obtain nitrided layer structure with good binding force through plasma nitriding and can effectively reduce nitriding temperature.

关 键 词：钛合金 缝隙腐蚀 离子渗氮 表面纳米化 

分 类 号：TG166.5[金属学及工艺—热处理] TG172[金属学及工艺—金属学]