不同稀土掺杂固体渗铬对Cr-RE渗层结构及性能的影响  

Influence of Solid Chromizing Doped with Various Rare Earths on Microstructures and Properties of Cr-RE Coatings Fabricated by Pack Cementation

作　　者：唐相国 代明江 韦春贝 匡同春[1] 林松盛 侯惠君 TANG Xiang-guo;DAI Ming-jiang;WEI Chun-bei;KUANG Tong-chun;LIN Song-sheng;HOU Hui-jun(School of Material Science and Engineering,South China University of Technology,Guangzhou 510640,China;National Engineering Laboratory for Modern Materials Surface Engineering Technology,Guangdong Institute of New Materials,Guangzhou 510651,China;Key Lab of Guangdong for Modern Surface Engineering Technology,Guangdong Institute of New Materials,Guangzhou 510651,China)

机构地区：[1]华南理工大学材料科学与工程学院,广州510640 [2]广东省新材料研究所现代材料表面工程技术国家工程实验室,广州510651 [3]广东省新材料研究所广东省现代表面工程技术重点实验室,广州510651

出　　处：《表面技术》2018年第10期157-164,共8页Surface Technology

基　　金：广东省科技计划项目(2017A070702016);广州市科技计划项目(201807010027)~~

摘　　要：目的改善GCr15轴承钢的表面性能,以满足其在重载恶劣工况下服役的要求。方法采用固体包埋法对GCr15轴承钢进行渗铬处理,通过添加不同的稀土氧化物La_2O_3、Y_2O_3和Ce O_2,获得三种Cr-RE渗层。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)、显微维氏硬度计、Rockwell-C硬度计及球-盘式摩擦磨损试验机,对Cr-RE渗层的表面形貌、截面形貌、物相组成、渗层成分、显微硬度、结合强度和摩擦磨损性能分别进行表征。结果不同稀土元素添加都能在GCr15轴承钢表面形成一层致密、连续的稀土改性渗铬层,其厚度为10μm,其中Cr-La渗层韧性和结合强度最好,其压痕等级为HF1。Cr-RE渗层主要由Cr_7C_3、Cr_2C和(Cr,Fe)_7C_3等相组成。Cr-RE渗层能显著提高基体表面硬度,其中Cr-Y渗层表面硬度最大可达1520 HV。三种Cr-RE渗层均有提高耐磨性和减摩作用,其中Cr-La渗层具有最好的摩擦学性能,其平均摩擦系数为0.4714,磨损率为4.4806×10^(-7 )mm^3/(N?m),其磨损机理为粘着转移和氧化磨损。结论稀土掺杂渗铬能有效改善渗铬层的韧性和耐磨性,其中Cr-La渗层综合性能最好。Thework aims to improve the surface properties of GCr15 bearing steel to meet the service requirements under severe load conditions.The chromizing treatment was conducted on GCr15 bearing steel surface by pack cementation.Three kinds of Cr-RE chromizing coatings were obtained by adding different rare earth oxides(such as La2O3,Y2O3 and CeO2).The surface and cross-section morphologies,phase composition,chromizing coating composition,microhardness,bond strength and friction and wear properties of the Cr-RE coatings were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),Energy Dispersive Spectrometer(EDS),Micro Vickers tester,Rockwell-C hardness tester and ball-on-disc wear tester.From the results,the addition of any rare earth could form a uniform,continuous and compact rare earth modified chromizing coating with thickness of 10μm on the surface of GCr15 bearing steel.The Cr-La coating had the best toughness and adhesion,and its indentation grade was HF1.The coatings were mainly composed of Cr7C3,Cr2C and(Cr,Fe)7C3.The Cr-RE coating significantly increased the surface hardness,and the Cr-Y coating had the highest surface hardness of 1520HV.These three Cr-RE coatings could improve friction and wear resistance.The Cr-La coating showed the best tribological properties with average friction coefficient of 0.4714 and wear rate of 4.4806×10^-7mm^3/(N·m)and the wear mechanism was adhesion transfer and oxidation wear.Chromizing doped with rare earth can improve the toughness and wear resistance of the chromizing layer and Cr-La coating has the best comprehensive performance.

关 键 词：GCR15轴承钢 Cr-RE渗层 稀土氧化物 摩擦磨损性能 固体包埋法 

分 类 号：TG156.8[金属学及工艺—热处理]