GCr15销轴固体渗Cr层的生长机制及孔隙成因探索  

Growth Mechanism and Pore Formation of Solid Chromizing Layer of GCr15 Pin

作　　者：王海峰 王灿明[1] 刘婷婷 宋强[1] 薛云岭 马庆超 崔洪芝[1,4] Wang Haifeng;Wang Canming;Liu Tingting;Song Qiang;Xue Yunling;Ma Qingchao;Cui Hongzhi(School of Materials Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China;Jinan Tianmeng New Material Technology Co.,Ltd,Jinan 250000,China;Hehong New Material Technology Co.,Ltd,Weihai 264200,China;School of Materials Science and Engineering,Ocean University of China,Qingdao 266100,China)

机构地区：[1]山东科技大学材料科学与工程学院,山东青岛266590 [2]济南天盟新材料科技有限公司,山东济南250000 [3]合鸿新材科技有限公司,山东威海264200 [4]中国海洋大学材料科学与工程学院,山东青岛266100

出　　处：《稀有金属材料与工程》2023年第5期1809-1818,共10页Rare Metal Materials and Engineering

基　　金：山东省自然科学基金(ZR2020ME015);泰山学者攀登计划(tspd20161006)。

摘　　要：低扩渗效率和渗层孔隙是困扰着渗铬生产的2个重要难题。本研究采用固体包埋法在GCr15表面制备渗Cr涂层,重点探讨了渗层的生长机制、孔隙成因及不同稀土氧化物的催渗作用。结果表明,加入稀土氧化物后渗层厚度明显提高,3种稀土氧化物的催渗效率依次为Y_(2)O_(3)>CeO_(2)>La_(2)O_(3)。渗Cr层明显的分为双层结构,外层是以(Cr,Fe)_(23)C_(6)相为主的多孔层,内层为(Cr,Fe)_(7)C_(3)相为主的致密层。扩渗初期在基材表面首先生成的(Cr,Fe)_(23)C_(6)相层阻碍了表面活性Cr原子向内扩散,其自身作为Cr源向内扩散促进了致密层的生长,Cr原子扩散速度的差异及渗层中的应力是产生孔隙的主要原因。发现降低基体碳含量抑制(Cr,Fe)_(23)C_(6)相层的生成或细化该相层晶粒增加Cr原子扩散通道可有效降低孔隙率,这为改进渗铬层质量提供了一个重要思路。Low diffusion efficiency and porous layer are two important problems in chromizing production.In this research,Cr-permeable coating was prepared on GCr15 surface by solid embedding method.The growth mechanism of permeable layer,pore formation and the effect of different rare earth oxides on permeable layer were discussed.The results show that the permeability layer thickness increases obviously after adding rare earth oxides,and the permeability efficiency of the three rare earth oxides is Y_(2)O_(3)>CeO_(2)>La_(2)O_(3).The Cr permeable layer is obviously divided into two layers,the outer layer is porous layer dominated by(Cr,Fe)_(23)C_(6) phase,and the inner layer is dense layer dominated by(Cr,Fe)_(7)C_(3) phase.The(Cr,Fe)_(23)C_(6) phase layer,which is first generated on the substrate surface at the early stage of diffusion,inhibits the inward diffusion of active Cr atoms and promotes the growth of the dense layer as a Cr source.The difference in the diffusion rate of Cr atoms and the stress in the permeable layer are the main reasons for the formation of pores.It is found that reducing the carbon content of substrate inhibits the formation of(Cr,Fe)_(23)C_(6) phase layer or refines the grain of the phase layer to increase the diffusion channel of Cr atom which can effectively reduce the porosity.It provides an important idea for improving the quality of chromizing layer.

关 键 词：GCR15 固体渗Cr 孔隙成因 稀土催渗 销轴 

分 类 号：TG174.445[金属学及工艺—金属表面处理]