基于HSC-Chemistry的316L包埋渗铬过程热力学分析  

Thermodynamic Analysis of 316L Embedded Chromium Infiltration Process Based on HSC-Chemistry

作　　者：常晟 任国雄 崔永颢 李艳梅 王昭东 CHANG Sheng;REN Guoxiong;CUI Yonghao;LI Yanmei;WANG Zhaodong(State Key Laboratory of Rolling Technology and Continuous Rolling Automation,Northeastern University,Shenyang 11000,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110000

出　　处：《金属材料与冶金工程》2023年第2期16-25,共10页Metal Materials and Metallurgy Engineering

摘　　要：利用HSC-Chemistry热力学软件探究了包埋渗铬过程中活性铬原子的产生机理和工艺条件对活性含铬物质的影响,并解释了催渗剂的选择和铬原子的扩散方式。结果表明:纯铬在高温下具有很低的饱和蒸汽压,必须借助渗铬剂来增加渗铬过程中的铬势;对比三种卤化铵催渗剂(NH_(4)Cl、NH_(4)Br、NH_(4)I),NH_(4)I有着最高的活性含铬物质的生成量和生成速率;高温下的实质渗铬物质为CrI,且温度升高或者压强减小均可使得活性CrI的生成量增加,在1050~1150℃范围内,CrI的生成量差别不大;由活性CrI最终在基体表面形成活性Cr原子的反应为Fe的置换反应和H2的还原反应,自身的热分解反应在热力学上不可行;高温下,铬的扩散方式为沿晶界的空位扩散,随温度升高,空位浓度增加,1150℃下单位体积奥氏体γ-Fe中的空位数约为1000℃下的5倍。The HSC-Chemistry thermodynamics software was used to explore the generation mechanism of active chromium atoms and the influence of process conditions on active chromium-containing substances during the process of embedding chromizing,and this paper explained the selection of catalysts and the diffusion mode of chromium atoms.The results show that pure chromium has a very low saturated vapor pressure at high temperature,and it must use a chromizing agent to increase the chromium potential in the process of chromizing,and among the three ammonium halides(NH_(4)Cl、NH_(4)Br、NH_(4)I).NH_(4)I has the highest generation amount of active chromium-containing substances and the formation rate.The substantial chromizing substance at high temperature is CrI,and the formation of active CrI can increase with the increase of temperature or the reduction of pressure.In the range of 1050~1150℃,the formation of CrI has little difference.The final reaction of CrI to form active Cr atoms on the surface of the substrate should be the replacement reaction of Fe and the reduction reaction of H2,and its own thermal decomposition reaction is thermodynamically infeasible.At high temperature,the diffusion mode of chromium is the vacancy diffusion along the grain boundary.With the increase of temperature,the vacancy concentration increases,and the number of vacancies in unit volume of austeniteγ-Fe at 1150℃is about 5 times that of at 1000℃.

关 键 词：HSC-Chemistry软件 固体粉末包埋法 渗铬气氛 空位扩散 

分 类 号：TG156.88[金属学及工艺—热处理]