不锈钢表面渗铝并热氧化处理对氢渗透的影响  

EFFECT OF PACK ALUMINIZING PLUS THERMAL OXIDATION TREATMENT OF STAINLESS STEEL ON HYDROGEN PERMEATIN

作　　者：沈嘉年[1] 李凌峰[1] 张玉娟[1] 李谋成[1] 刘冬[1] 

机构地区：[1]上海大学材料研究所,上海200072

出　　处：《腐蚀科学与防护技术》2005年第1期15-19,共5页Corrosion Science and Protection Technology

摘　　要：首先 ,采用固体粉末包埋法在不锈钢表面渗铝 .渗铝层表面是呈较粗大的结晶状致密组织 ,主要由FeAl相组成 .渗层呈多层结构 ,分为外层 (约 2 5 μm) ,过渡层 (约 5 μm)和内层 (约 30 μm) ,各亚层间及渗层与基体间结合紧密 ,无裂缝 .渗铝表层铝浓度较高 ,超过 30mass % .然后 ,采用热氧化的方法 ,使渗铝层发生选择性氧化 ,在表面生成了一薄层均匀、致密的Al2 O3 膜 .在 90 0℃ ,2 0× 10 -2 Pa氧气环境中氧化 2小时所生长的膜的厚度约为 0 6 μm .将氧化后的样品放入超高真空吸放氢测试系统中进行渗氢处理 ,再用前向弹性反冲 (ERD)测定渗氢样品中氢的分布 .结果表明 :沿着膜层深度方向 ,氢原子浓度急剧降低 .在深度为 0 2 μm处 ,原子浓度趋于平衡 ,原子百分比浓度大约保持在 0 0 0 7at%左右 ,与不锈钢基体化学组成中氢原子含量相近 ,氢原子难以渗透进去 .这说明本研究制备的Al2 O3In this paper,A technique that preparing Al 2O 3 barrier film on surface of stainless steels (00Cr17Ni14Mo2 and 1Cr18Ni9Ti) have been studied.In order to test the permeation behavior,hydrogen was used to simulate deuterium and tritium.Firstly,pack cementation aluminizing process had been adopted to form a aluminum rich layer on the surface of stainless steels.The aluminizing layer shows multiplayer characteristics which consists of inner layer (25 μm),external layer (5 μm) and transitional layer (30 μm).The good adherence can be seen between the sub-layers and the interface between the layer and substrate as observed by metallography.The weight concentration of the element Al in the aluminizing layer exceeds 30 mass %.Then thermal oxidation processes were taken on the aluminized layer to form the Al 2O 3 film.It shows that an uniform and compact Al 2O 3 film is grown on the aluminizing layer.The film thickness is about 0.6μm when oxidized at 900℃ for 2 h in 2 0×10 -2 Torr oxygen pressure.In order to examine the hydrogen permeation property of the materials,the hydrogen permeation treatment were taken to both the aluminied and bare steds.Then the amount of hydrogen in the surface region of the steels was measured by elastic recoil detection (ERD) method.It was found that the content of hydrogen dropped gradually with the increasing distance to the surface.And the hydrogen content at the distance of 0 2 μm from the surface is 0 007 at% that is about the hydrogen content of the received stainless steel.This implies that the hydrogen atoms can not diffuse through the formed Al 2O 3 barrier film.The aluminization plus oxidation to form the Al 2O 3 barrier film is an effective method for resisting the permeation of hydrogen and its isotopes.

关 键 词：氢渗透 渗铝层 渗层 渗氢 表面 膜层 不锈钢 热氧化 铝浓度 外层 

分 类 号：TQ153[化学工程—电化学工业] TG174[金属学及工艺—金属表面处理]