摘要
为了优选出合理的夹具材料用于制备00Cr18Ni10N超低碳奥氏体不锈钢真空扩散连接接头,分别采用中性盐雾腐蚀试验方法和电化学阻抗谱(EIS)测试方法对比研究了氮化硼与石墨夹具材料对00Cr18Ni10N钢扩散连接接头在Na Cl腐蚀环境中的耐蚀行为。研究结果表明:采用氮化硼夹具制备的00Cr18Ni10N不锈钢扩散连接接头保持了与基材接近的耐蚀性能,未发生点蚀和晶间腐蚀;使用石墨夹具制备的00Cr18Ni10N不锈钢扩散连接接头的耐蚀性能比基材显著降低,出现了较为严重的晶间腐蚀现象。电化学测试表明:采用石墨夹具制备的连接接头试样自腐蚀电流密度比不锈钢基材和采用氮化硼夹具制备的连接接头试样高一个数量级,其表面阻抗较基材低两个数量级。原因归于使用石墨夹具制备不锈钢扩散连接接头时,石墨夹具的碳原子扩散到不锈钢表层形成了碳的过饱和固溶体,而在随炉冷却过程中碳与铬及铁在晶界形成了碳化物(Cr Fe)7C3,造成不锈钢表层出现晶间贫铬现象,促进了晶间腐蚀的发生,进而导致该区域耐蚀性能降低。
In order to select the optimum fixture materials for vacuum diffusion bonding of 00Cr18Ni10 N stainless steel,joints with boron nitride( BN) and graphite as fixture material were prepared. The effect of the fixture materials on the corrosion behavior of joints was studied by neutral salt spray corrosion test and electrochemical impedance spectroscopy( EIS) test. The experimental results show that the joint with BN as fixture material maintained similar corrosion resistance with the substrate,and no corrosion occurred. However,the corrosion resistance of the joint with graphite as fixture material decreased significantly and the joint suffered severe intergranular corrosion. Furthermore,the electrochemical tests indicated that the corrosion current density of the joint with graphite as fixture material is higher than that of stainless steel substrate and the joint manufactured with BN fixture by an order of magnitude. While its resistance is lower than that of substrate with two orders of magnitude. The reason lies in the fact that carbon atoms of graphite fixture diffused to the surface of stainless steel and it led to the formation of a supersaturated solid solution of carbon during the bonding process. In the cooling process,carbon,chromium and iron formed carbide( Cr Fe) 7C3 in grain boundary,which caused intergranular chromium depletion on the surface of stainless steel. So the corrosion resistance of bonding area was reduced and intergranular corrosion occurred.
出处
《机械科学与技术》
CSCD
北大核心
2015年第6期949-952,共4页
Mechanical Science and Technology for Aerospace Engineering
基金
国家自然科学基金项目(51171154)资助
关键词
00Cr18Ni10N超低碳不锈钢
真空扩散连接
晶间腐蚀
电化学阻抗谱
00Cr18Ni10N
bonding
boron nitride
corrosion
design of experiments
digital cameras
electrochemical impedance spectroscopy
experiments
grain boundaries
intergranular corrosion
schematic diagrams
stainless steel
vacuum diffusion bonding
