真空熔覆Ni基复合涂层的制备及性能研究  

Preparation and Properties of Vacuum Cladding Ni-based Composite Coating

作　　者：伍康凯 张子健 李松泽 王龙龙 李明科 衣雪梅[1] WU Kang-kai;ZHANG Zi-jian;LI Song-ze;WANG Long-long;LI Ming-ke;YI Xue-mei(College of Mechanical and Electronic Engineering,Northwest A&F University,Shaanxi Yangling 712100,China)

机构地区：[1]西北农林科技大学机械与电子工程学院,陕西杨凌712100

出　　处：《表面技术》2023年第5期111-120,130,共11页Surface Technology

摘　　要：目的 提高65Mn钢的耐磨性和耐酸碱腐蚀性能。方法 通过真空熔覆技术在65Mn钢表面制备了Ni基-碳化钨(WC)复合涂层,并加入稀土氧化铈(CeO_(2))改善其微观缺陷。采用扫描电子显微镜(SEM)结合能谱仪(EDS)观察涂层微观结构和元素分布,X射线衍射仪(XRD)测定涂层物相成分,维氏显微硬度计测试涂层硬度。采用带有干涉镜头的摩擦磨损试验机测定涂层的摩擦因数,并通过三维形貌图获取磨痕宽度、深度和体积磨损量,通过磨痕扫描形貌分析摩擦磨损机理。采用电化学工作站分别测试涂层在酸性和碱性腐蚀介质中的电化学性能。结果 涂层以(Ni,Cr,Fe)固溶体、WC及含W增强相的Cr_(4)Ni_(15)W和Ni_(17)W_(3)作为主要的强化相组成。涂层随硬质相WC含量的增加而出现孔洞、裂纹等缺陷,在CeO_(2)的改善作用下,质量分数为30%的WC硬质相涂层组织致密,无明显缺陷,平均显微硬度达900HV1~1 000HV1,是基体硬度的3~4倍;摩擦磨损性能较65Mn钢基体有明显提高,在不同试验条件下,其体积磨损率仅为65Mn钢基体的13.1%~17.4%,但摩擦因数略高于基体。磨痕分析表明,磨损机制主要以磨粒磨损为主,并伴随着选择性磨损和脱层磨损。电化学测试结果显示,涂层耐碱性腐蚀性能优于耐酸性,且均优于基体。结论 在以磨损为主、兼顾防腐的实际工况下,30%WC+2%CeO_(2)(质量分数)组合的Ni基复合涂层性能最佳,此时熔覆涂层组织致密、无明显缺陷、与基体结合良好,具有优异的耐磨、耐酸碱腐蚀性能。As a promising technology,vacuum cladding shows significant advantages of controllable coating thickness,controllable defects,small thermal deformation of the substrate,suitable for irregular shaped parts,low cladding cost,and so on.However,due to its wettability and addition ratio,the quality of the cladding coating could be affected when cladding ceramic materials.The work aims to improve the friction and wear resistance as well as the acid and alkali corrosion resistance of 65Mn steel steel.Ni-based-WC composite coatings were prepared on the surface of 65Mn steel(10 mm×10 mm×5 mm)by means of vacuum tube furnace.The CeO_(2) was introduced mainly to decrease the defects in the coating.The experimental parameters were set as:vacuum degree of 10-2 Pa,cladding temperature of 1 100 ℃,holding time of 60 min,cladding thickness of 1 mm.The results indicated that the Ni-based composite coating with the combination of 30wt.%WC+2wt.%CeO_(2) displayed the best performance.It had the relatively uniform hardness distribution,and the average microhardness reached 900HV1-1000HV1,which was 3 to 4 times of that of the base 65Mn steel(without heat treatment).At the friction and wear test conditions of 10 N/8Hz,20 N/8 Hz and 30 N/6 Hz,the volume wear rates were only 17.6%,18.8% and 16.1% of the matrix,respectively.With the addition of 2wt.% CeO_(2),the friction and wear performance were further improved.The wear rates reduced to only 13.1%,17.4% and 14.3% of the matrix,and the corresponding friction coefficients were slightly higher than that of the matrix.The SEM,EDS and XRD analyses demonstrated that the coating was mainly composed of strengthening phases such as(Ni,Cr,Fe)solid solution,WC as well as W-containing reinforcing phases Cr4Ni15W and Ni17W3.The appropriate cladding temperature could make the WC distribution more uniform.The addition of CeO_(2) could reduce the melting point of Ni-based alloy,and promote the element diffusion between the liquid phase alloy and the substrate,making the coating diffusion layer nearly

关 键 词：65MN钢 真空熔覆 NI基合金 稀土CeO_(2) 耐磨防腐性能 磨损机理 

分 类 号：TB333[一般工业技术—材料科学与工程]