低温低压电弧等离子体渗氮处理316不锈钢的耐腐蚀性能  

Corrosion Resistance of 316 Stainless Steel after Low-temperature Low-pressure Arc Plasma Nitriding

作　　者：杨文进[1,2] 赵彦辉[2] 沈明礼[2] 刘占奇 肖金泉[2] 宫骏[2] 于宝海[2] 孙超[2] YANG Wenjin ZHAO Yanhui SHEN Mingli LIU Zhanqi XIAO Jinquan GONG Jun YU Baohai SUN Chao(School of Materials Science and Engineering, University of Science and Technology of China, Anhui 230027, China Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)

机构地区：[1]中国科学技术大学材料科学与工程学院,合肥230027 [2]中国科学院金属研究所,沈阳110016

出　　处：《材料研究学报》2017年第2期81-87,共7页Chinese Journal of Materials Research

基　　金：国家自然科学基金(51171197)~~

摘　　要：在低温下对316奥氏体不锈钢进行低压电弧等离子体渗氮处理,研究了渗氮处理对不锈钢耐腐蚀性能的影响。结果表明:渗氮层有两个子层,由纳米晶扩张奥氏体和少量的Cr N化合物组成的外表层和单一结构的扩张奥氏体内层。由于低压电弧等离子体浓度高,在400℃渗氮1 h得到的渗氮层厚度达到15μm,表现出很高的渗氮速率。纳米晶外表层是渗氮不锈钢耐腐蚀性能的关键,促进了钝化膜的生成,渗氮后试样表面形成的钝化膜厚度达到27 nm,比原始不锈钢钝化膜的2倍还多。渗氮不锈钢试样的腐蚀电流(3.55×10^(-8)A/cm^2)比基材的腐蚀电流(1.99×10^(-7)A/cm^2)降低一个数量级,表明渗氮后试样的耐腐蚀性能提高了。Low-pressure arc plasma nitriding is a novel rapid plasma nitriding process which can significantly enhance wear and corrosion resistance of austenite stainless steels. In this study, low temperature （~ 400℃） nitriding was applied to AISI 316 austenitic stainless steel （316 SS）. A nitriding layer of 15 μm thickness was obtained just after 1 h processing, which is composed of an outer thin sublayer of nanocrystalline expanded austenite （nano-γN） with a trace of Cr nitrides and an inner thick coarse-grained expanded austenite （γN） sublayer. The thin surface nanolayer plays the key role in corrosion resistance of the nitrided layer, which promotes the formation of passive film. And the thickness of the passive film formed on the surface of the nitrided steel is 27 nm, which is two times over that on the bare 316 stainless steel. The corrosion current of nitrided steel is 3.55×10^-8 A/cm^2 in 3.5% NaCl solution, c.a. one order of magnitude lower than that of the untreated 316 austenite stainless steel （1.99×10^-7 A/cm^2）, which indicated that the nitrided layer had a lower corrosion rate. The pitting corrosion potential was not detected via electrochemical polarization experiments, exhibiting a better pitting corrosion resistance of the nitrided steel.

关 键 词：材料失效与保护 低压电弧等离子体渗氮 纳米晶扩张奥氏体 渗氮速率 耐腐蚀性能 

分 类 号：TB304[一般工业技术—材料科学与工程]