氧化钇对TC4钛合金表面包埋渗硼的影响  

Effects of Y_(2)O_(3) on Pack Boronizing of TC4 Titanium Alloy

作　　者：韩宾龙 田晓东 卢鹏军 祁贤 HAN Bin-long;TIAN Xiao-dong;LU Peng-jun;QI Xian(Engineering Research Center of Transportation Materials of Ministry of Education,School of Materials Science and Engineering,Chang'an University,Xi'an 710064,China)

机构地区：[1]长安大学材料科学与工程学院交通铺面材料教育部工程研究中心,西安710064

出　　处：《表面技术》2023年第8期451-457,共7页Surface Technology

基　　金：大学生创新创业训练项目(X202210710586);长安大学中央高校基本科研业务费专项资金(300102311403)。

摘　　要：目的加快TC4钛合金表面固体渗硼时渗层的生长,研究渗剂中添加Y_(2)O_(3)对渗硼的影响。方法采用固体粉末包埋渗法对TC4基材进行1050℃/8 h渗硼,包括渗剂中不添加Y_(2)O_(3)以及渗剂中分别添加质量分数为1%、3%、5%、7%Y_(2)O_(3)的试验研究。通过扫描电子显微镜、能谱仪、波谱仪和X射线衍射仪分析渗硼样品的截面形貌、元素含量和表面物相,并测量渗硼样品的表面硬度和摩擦系数。结果在渗剂中加入1%~7%的Y_(2)O_(3),渗硼层结构与未添加氧化钇渗剂形成的相同,由致密连续的TiB_(2)层和TiB晶须扩散层组成。Y_(2)O_(3)促进渗层生长的作用与其添加量密切相关。渗剂中加入1%~3%的Y_(2)O_(3)有促进渗硼层生长的作用,且加入3%的Y_(2)O_(3)时,催渗效果最佳,可使渗硼层厚度增加40.24%,但加入5%~7%的Y_(2)O_(3)时反而会抑制渗硼层的生长。能谱分析表明,Y原子能够扩散到渗硼层内,且渗硼层中存在原子数分数为0.01%~0.34%的微量Y元素,其随渗剂中Y_(2)O_(3)含量的增加而增加。热力学分析发现,Y_(2)O_(3)参与渗剂反应形成活性Y原子而渗入基体。向渗硼试剂中加入3%的Y_(2)O_(3),样品的表面硬度较未添加Y_(2)O_(3)时提高35.54%,摩擦系数较未添加Y_(2)O_(3)时降低28.57%。结论向渗硼试剂中加入适量氧化钇,是获得TC4合金表面高渗速、高硬度和低摩擦系数渗硼层的一种有效方法。In order to accelerate the growth of the boronizing layer on TC4 titanium alloy prepared through pack cementation process,the effects of adding Y_(2)O_(3) into the pack mixture were investigated.The TC4 matrix was boronized at 1050℃ for 8 h with the pack mixtures composed of NaF,B and Al_(2)O_(3) powders with Y_(2)O_(3) free and Y_(2)O_(3) addition of 1,3,5 and 7 wt.%.The SEM,EDS,WDS and XRD instruments were applied to analyze the morphology,composition and constituent phases of the boronizing layer.And the surface hardness and the friction coefficient of the boronizing sample were evaluated through a microhardness tester and a ball and disc type friction and wear tester,respectively.When adding 1wt.%~7wt.%Y_(2)O_(3)into the pack mixture,the boronizing layer obtained on the TC4 substrate was composed of the dense and continuous TiB_(2)layer and the TiB whisker diffusion layer,which had the same structure as the boronizing layer prepared in the Y_(2)O_(3)free pack mixture.The catalytic diffusion effect of Y_(2)O_(3)on the boronizing layer growth was related to the amount of Y_(2)O_(3)addition into the pack mixture.Adding 1wt.%~3wt.%Y_(2)O_(3)into the pack mixture increased the thickness of the boronizing layer by up to 40.24%compared with that of the boronizing layer prepared in the Y_(2)O_(3)free pack mixture.The best catalytic diffusion effect of Y_(2)O_(3)on the boronizing layer growth occurred in the pack mixture with 3wt.%Y_(2)O_(3)addition.Nevertheless,adding 5wt.%~7wt.%Y_(2)O_(3)into the pack mixture restrained the growth of the boronizing layer.The EDS analysis showed that Y atoms could diffuse into the boronizing layer,and the content of Y element in the boronizing layer was about 0.01at.%to 0.34at.%.which increased with the rising of Y_(2)O_(3)content in the pack mixture.Thermodynamics analysis revealed that Y_(2)O_(3)could take part in the reactions of the pack mixture to form reactive Y atoms.When Y atoms were slightly incorporated into the boronizing layer,it prompted the matrix lattice distortion a

关 键 词：渗硼 包埋渗 氧化钇 催渗 

分 类 号：TG156.87[金属学及工艺—热处理]