面向石墨模具精密加工的金刚石涂层结构及性能  

Structure and Performance of Diamond Coating for Graphite Mold Precision Machining

作　　者：李洪 许伟 苏一凡 林松盛 代明江 石倩 LI Hong;XU Wei;SU Yifan;LIN Songsheng;DAI Mingjiang;SHI Qian(The Key Laboratory of Guangdong for Modern Surface Engineering Technology,National Engineering Laboratory for Modern Materials Surface Engineering Technology,Guangdong Institute of New Materials,Guangdong Academy of Sciences,Guangzhou 510650,China)

机构地区：[1]广东省科学院,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,广东省现代表面工程技术重点实验室,广州510650

出　　处：《材料导报》2021年第14期14030-14034,共5页Materials Reports

基　　金：广东省重点领域研发计划项目(2020B010185001);广州市重点领域研发计划项目(202007020008);广东省科学院项目(2020GDASYL-20200105004,2018GDASCX-0402,2018GDASCX-0111)。

摘　　要：金刚石涂层具有接近天然金刚石的超高硬度及耐磨性,被认为是精密加工石墨模具的理想刀具涂层材料。金刚石涂层与刀具基体间的结合力及涂层表面状态是高速干式切削加工质量及效率的关键,金刚石涂层前处理过程控制及涂层工艺是影响金刚石涂层刀具综合性能的重要因素。本工作基于热丝化学气相沉积技术,采用酸-碱-酸三步法对硬质合金材料进行前处理,在涂层沉积过程中采用大气流量及高炉压沉积工艺在刀具基体表面沉积金刚石涂层。采用扫描电镜(SEM)、原子力显微镜(AFM)、拉曼光谱(Raman)、X射线衍射光谱(XRD)对涂层微观结构及物相结构进行分析表征,利用纳米压痕仪对金刚石涂层硬度进行测试,利用喷砂试验测试金刚石涂层的抗冲刷性能,利用石墨模具切削试验表征金刚石涂层刀具的切削性能。结果表明,金刚石涂层呈典型八面体结构,涂层与基体紧密结合、无明显孔隙,金刚石涂层刀具表面粗糙度为157 nm,sp3键含量大于98%,(涂层硬度大于90 GPa),涂层沿(111)面择优生长,抗冲刷时间大于150 s(0.5 MPa,120目),涂层刀具高速切削石墨模具2 h后,被加工面表面粗糙度小于1μm,达到进口刀具水平。切削完成后刀具前刀面出现少量崩缺,前刀面磨损是此类刀具加工石墨模具的主要磨损形式。Diamond coating has ultra-high hardness and wear resistance which was close to that of natural diamond,and is considered to be an ideal tool coating material for precision machining of graphite molds.The bonding force between the diamond coating and the substrate,and the surface state of the coating are the keys to the quality and efficiency of high-speed dry cutting.The pre-treatment of the diamond coating and the coating process are important factors that affect the property of the diamond-coated tool.This article used acid-alkali-acid three-step method to pre-treat the cemented carbide materials based on hot-wire chemical vapor deposition technology.Atmospheric flow rate and high pressure deposition process were used to deposit diamond coating on the tool substrate.Scanning electron microscope(SEM),atomic force microscope(AFM),Raman spectroscopy(Raman),X-ray diffraction spectroscopy(XRD)were used to analyze and characterize the coating microstructure and phase structure.The sand blast test was used to test the erosion resistance of the diamond coating,and the graphite mold cutting test was used to characterize the cutting performance of the diamond coated tool.The results show that the diamond coating has a typical octahedral structure,the coating and the substrate are closely combined without obvious pores,the surface roughness of the diamond coated tool is about 150 nm,the content sp3 is more than 98%,the coating hardness is higher than 90 GPa,diamond coating grows preferentially along the(111)plane,the erosion resistance time is greater than 150 s(0.5 MPa,120 mesh),the roughness of the processed surface is less than 1μm after high-speed cutting graphite mold for 2 h,reaching the level of imported tools.There is a small amount of chipping on the rake face of the tool after the cutting.Therefore,the wear of the rake face is the main form of wear for processing graphite molds.

关 键 词：金刚石涂层 刀具 石墨模具 结构及性能 

分 类 号：TG174.444[金属学及工艺—金属表面处理]