硬质合金基体腐蚀工艺对金刚石薄膜的影响

采用不同的预处理方式浸蚀YG6硬质合金基体表面,随后在热丝化学气相沉积装置上沉积了金刚石薄膜.用扫描电子显微镜、x射线衍射仪以及洛氏硬度计对样品进行了分析检测.结果表明:一步或两步浸蚀法都能抑制沉积过程中基体表面钴的不利影响.采用两步法,即Murakami剂30 min腐蚀碳化钨相,再用H2SO4:H2O2=3:7(体积比)混合酸腐蚀30 s去除钴相,基体表面粗糙,金刚石薄膜形核密度高,结晶质量较好,金刚石涂层与硬质合金基体结合良好.     

YG13硼化处理后沉积气压对金刚石薄膜的影响

采用超高真空热丝化学气相沉积（HFCVD）系统,以甲烷和氢气为反应气体,在YG13（WC-13%Co）硬质合金基体上沉积金刚石薄膜。用场发射扫描电子显微镜（FESEM）和X射线衍射仪（XRD）对金刚石薄膜进行检测分析,研究YG13经950℃、3h硼化预处理后沉积气压对金刚石薄膜形貌和生长织构的影响;通过压痕法比较硼化与二步法两种预处理方法对金刚石薄膜附着性能的影响。结果表明,基体经硼化预处理后表面形成CoB、CoW2B2、CoW3B3相;当沉积温度为750～800℃,碳源浓度为3.3%时,薄膜表面形貌和生长织构随着沉积气压改变有明显的变化;硼化预处理后所得样品在1500N载荷下压痕表现出良好的附着性能,较二步法预处理更加有效地改善了膜-基附着性能。     

沉积温度对硬质合金金刚石涂层附着力影响的研究

采用压痕实验、扫描电镜与激光Raman光谱分析,实验研究了酸浸硬质合金基底上金刚石涂层的附着力随沉积温度的变化.结果表明,涂层质量随沉积温度降低而显著恶化,涂层应力则随沉积温度提高而上升.从提高涂层附着力的角度考虑,存在一个最佳沉积温度.在较低的沉积温度下,涂层自身的质量较低、力学性能较差,在载荷作用下易于破坏.提高沉积温度,涂层自身的质量可得到改善,但基底中的钴向基底表面扩散的倾向加大,而且热应力增大,会严重降低涂层与基底的附着力.除硬质合金基底的预处理工艺外,沉积工艺对金刚石涂层的组织、性能以及附着力均有重要影响.     

硬质合金基体金刚石薄膜摩擦学性能研究的进展

硬质合金基体表面沉积金刚石薄膜可以提高其硬度和耐磨性,延长其使用寿命,有效保护和节约钨、钴等稀有金属。作为一种多晶膜,金刚石薄膜的摩擦系数直接影响了其在摩擦学领域的应用。对近年来硬质合金基体表面CVD金刚石薄膜的摩擦磨损性能的研究状况进行了阐述,分析了CVD金刚石薄膜在摩擦实验过程中的摩擦磨损机制,并对金刚石薄膜在摩擦学领域中的应用研究进行了展望。     

硬质合金上沉积金刚石膜的基体预处理方法进展

本文重点对近年硬质合金基体表面预处理方法及其对CVD金刚石膜沉积的影响进行了综述。按其原理来分,预处理方法可分为物理预处理法、化学预处理法以及中间层法。大量实验结果表明通过适当的预处理能有效消除或抑制基体中钴黏结相的负面影响,提高金刚石的形核密度以及膜基结合力,从而获得理想的薄膜质量。     

Comparative investigation of smooth polycrystalline diamond films on dental burs by chemical vapor deposition

Depositions of hot filament chemical vapor-deposited diamond on cobalt-cemented tungsten carbide (WC-Co) rotary cutting dental burs are presented. Conventional dental tools made of sintered polycrystalline diamond have a number of problems associated with the heterogeneity of the crystallite, decreased cutting efficiency, and short life. A preferential (111) faceted diamond was obtained after 15 h of deposition at a growth rate of 1.1 μm/h. Diamond-coated WC-Co dental burs and conventional sintered burs are mainly used in turning, milling, and drilling operations for machining metal ceramic hard alloys such as CoCr, composite teeth, and aluminum alloy in the dental laboratory. The influence of structure, the mechanical characteristics of both diamond grains and hard alloys on the wear behavior, as well as the regimen of grinding on diamond wear are considered. Erosion wear properties are also investigated under air-sand erosion testing. After machining with excessive cutting performance, calculations can be made on flank and crater wear areas. Diamond-coated WC-Co dental burs offered significantly better erosion and wear resistance compared with uncoated WC-Co tools and sintered burs. This paper was presented at the fourth International Surface Engineering Congress and Exposition held August 1–3, 2005 in St. Paul, MN.     

沉积参数对硬质合金基体微/纳米金刚石薄膜生长的影响

基体温度、反应压力和碳源浓度等沉积参数决定热丝化学气相沉积金刚石薄膜的性能。运用正交试验方法,研究参数对硬质合金基体金刚石薄膜生长的综合作用。采用场发射扫描电镜（FE-SEM）、原子力显微镜（AFM）和拉曼（Raman）光谱检测薄膜的形貌结构、生长速率和成分。结果表明：随着基体温度的降低,金刚石形貌从锥形结构向团簇状结构转变;低反应压力有利于纳米金刚石薄膜的生成;生长速率受反应压力和碳源浓度综合作用的影响。     

Characterization of N-doped polycrystalline diamond films deposited on microgrinding tools

Chemical vapor deposited diamond films have many industrial applications but are assuming increasing importance in the area of microengineering, most notably in the development of diamond coated microgrinding tools. For these applications the control of structure and morphology is of critical importance. The crystallite size, orientation, surface roughness, and the degree of sp ³ character have a profound effect on the tribological properties of the films deposited. In this article, we present experimental results on the effects of nitrogen doping on the surface morphology, crystallite size, and wear of microgrinding tools. The sp ³ character optimizes at 200 ppm nitrogen, and above this value the surface becomes much smoother and crystal sizes decrease considerably. Fracture-induced wear of the diamond grain is the most important mechanism of material removal from a microgrinding tool during the grinding process. Fracture occurs as a consequence of tensile stresses induced into diamond grains by grinding forces to which they are subjected. The relationship between the wear of diamond coated grinding tools, component grinding forces, and induced stresses in the model diamond grains is described in detail. A significant correlation was found between the maximum value of tensile stress induced in the diamond grain and the appropriate wheel-wear parameter (grinding ratio). It was concluded that the magnitude of tensile stresses induced in the diamond grain by grinding forces at the rake face is the best indicator of tool wear during the grinding process.     

Novel techniques for selective diamond growth on various substrates

There is a need for selective diamond growth in microelectronic and tool industries. This research was di-rected towards novel approaches in the selective diamond growth on non- diamond substrates. Diamond film was selectively deposited on the copper substrate by laser- hydrocarbon liquid (benzene C₆H₆) inter-action at room temperature which was used as seed for subsequent growth of diamond by the hot filament chemical vapor deposition (HFCVD). Diamond was also selectively grown on the gold patterned alumina substrate by manipulating HFCVD processing conditions. Diamond was selectively grown on the pat-terned silicon wafer (without having any scratches).     

硬质合金表面渗硼处理对CVD金刚石涂层形成的影响

采用渗硼工艺对ＹＧ６硬质合金表面进行预处理,探讨了渗硼预处理对硬质合金金刚石薄膜涂层形成的影响。研究结果表明,渗硼时Ｃｏ在硬质合金表面同Ｂ形成ＣｏＢ、Ｃｏ２Ｂ化合物层。该硼化物层在金刚石沉积过程中,能有效阻挡硬质合金中粘结相Ｃｏ向表面扩散,消除了Ｃｏ对金刚石薄膜涂层形成时的不利影响,改善了薄膜涂层质量,提高了附着力。     

SiC衬底金刚石薄膜的制备与性能表征

用热丝CVD法,以丙酮和氢气为碳源,在SiC衬底上沉积金刚石薄膜,提出了分步变参数沉积法制备超细晶粒金刚石复合薄膜的新工艺.结果表明,合理控制工艺条件的新工艺,对金刚石薄膜质量、形貌和粗糙度、薄膜与衬底间的附着力以及薄膜的摩擦系数有显著影响,金刚石薄膜的平均晶粒尺寸从3 μm减小到0.3 μm,拉曼特征峰显示超细晶粒金刚石薄膜特征,涂层附着力好,超细晶粒金刚石薄膜的表面粗糙度和摩擦系数值显著下降,对获取实用化的SiC在基体上沉积高附着强度、低粗糙度金刚石薄膜的新技术具有重要的意义.     

Cutting Performance and Mechanism of RE Carbide Tools

In receni ten years, a series of grades of REcemented carbide tool materials, including P, Mand K grouPs, were made and obtained conuner-cial availability in China.This paPer is aimed to verify the overall cut-ting performance of RE carbide cutting toolthrough systematic exPerimenis, such as toollives, cutting force, tool-chiP friction coefficiefltand intemiPted machining. The action of ascarbide tool was identified with the aid of scan-ning electron microscope and energy specboanalysis.1…     

Effect of working pressure and temperature on ZnO film deposited on free-standing diamond substrates

The structure characteristic and electric performance of ZnO film deposited on nucleation side of free-standing diamond substrates under different heating temperatures (T_h) of substrate and working pressures (p) were studied. The structure of the ZnO films tested by X-ray diffraction shows that ZnO film of high c-axis orientation is deposited on the nucleation side of free-standing diamond substrate which is extremely smooth when T_h=250 °C and p=0.4 Pa. After annealing at 480 °C in N₂ atmosphere, the SEM and the AFM analyses demonstrate that the c-axis orientation of ZnO film is obviously enhanced. The resistivity of ZnO films also increases up to 8×10⁵ Ωcm which is observed by I–V test.     

CVD金刚石厚膜刀具及应用研究

热丝CVD法沉积金刚石厚膜为全晶质纯多晶金刚石材料,是制造切削刀具的理想材料。本文针对国内外CVD金刚石厚膜焊接刀具研究与应用中存在的关键技术问题,结合我所近期相关技术研究进展,重点介绍了其制造工艺及关键技术。     

金刚石表面镀钛对金刚石锯片性能的影响

金刚石表面镀钛与否对Co基和Cu-Sn基胎体抗弯强度、金刚石锯片切割性能的对比研究表明,金刚石表面镀钛可提高金刚石工具的寿命切割效率,采用扫描电镜对抗弯强度试验样品断面和使用过的锯片刀头的观察分析,确立了镀钛层与不同胎体的结合类型。     

进气方式对热丝CVD制备金刚石薄膜的影响

采用超高真空热丝化学气相沉积(HFCVD)系统,以甲烷和氢气为反应气体,在YG13(WC-13%Co)硬质合金基体上沉积金刚石薄膜.采用场发射扫描电子显微镜(FESEM)和X射线衍射仪(XRD)对金刚石薄膜进行检测分析,研究了反应气体的不同进气方式对金刚石薄膜的影响.结果表明,随着进气方式的改变,基体周围气氛的组成、密度和分布受到影响,金刚石薄膜的形核密度、表面形貌、生长织构均有明显的变化,所得金刚石晶粒的生长参数多为1.5<α<3,3~(1/2)/2<г<3~(1/2).     

基于粘着特性的刀具磨损机理研究

目的为了满足日益凸显的铍青铜加工需求,分析粘着特性、加工系统和刀具损伤之间的内在联系。方法 通过建立加工过程中刀具微观晶体受力模型,采用多维度正交实验方法 ,分析刀具接触面表面形态与力学波动的内在联系。尝试从刀具受力、频谱分析和粘着形式出发,解析刀具磨损、铣削特性和粘结过程,并通过扫描电子显微镜对磨损后的刀具表面及粘结物形貌进行了分类表征。结果在相同的切削速度下,加工中的粘着现象随着刀具直径的增大而加剧。而由于铣刀前-后刀面粘结物受力环境的差异,导致加工参数仅对Fx变化显著。对比粘结物形态、刀具损伤形态和不同加工参数下的刀具形貌,综合考虑刀具粘结物、磨损、破裂和脱落表面形态,不稳定的粘附过程虽然在加工的初期对刀具表面存在一定的保护作用,但随着粘结物的不断累积,粘结物侧向受力的不断增加,加剧了刀具的实际损伤。结论粘着特性是影响刀具使用寿命的重要因素。在实际加工过程中,由于冲击和磨损频率的相互干扰,增加了粘附特性对刀具磨损的影响。     

预处理对金刚石薄膜质量及结合力的影响

目的改善硬质合金表面金刚石薄膜的结合力。方法采用热丝CVD法在硬质合金基体上制备金刚石薄膜,研究对比喷砂+一步法、喷砂+两步法、Al Cr N过渡层和传统两步法这四种预处理对金刚石薄膜质量及其结合性能的影响。对预处理后硬质合金基体表面的形貌和粗糙度进行分析,并通过扫描电子显微镜、X射线衍射、拉曼光谱及洛氏硬度计表征金刚石薄膜的形貌、结构及性能。结果喷砂有利于在基体表面获得均匀分布的凹坑,提高金刚石的形核密度及均匀性,尤其改善了金刚石颗粒的团聚现象。Al Cr N过渡层虽然表面粗糙度不高,但有大量的凸起颗粒,提供了极佳的形核点,也在一定程度上优于传统两步法的表面金刚石形核密度。在金刚石薄膜沉积参数不变的前提下,传统两步法预处理获得的涂层结合力为HF4级,喷砂结合一步法和两步法获得的结合力分别达到了HF3级和HF1级,但Al Cr N过渡层的结合力表现较差。结论 Al Cr N过渡层能阻挡Co的扩散,提高了金刚石的纯度,但金刚石膜的内应力较大,结合力差。喷砂和刻蚀复合预处理不仅能提高金刚石的结晶质量和纯度,金刚石薄膜的结合力也得到改善。     

金刚石膜涂层硬质合金工具研究进展及产业化前景

金刚石具有最高的硬度，极低的摩擦因数，最高的热导率和极佳的化学稳定性，因此是最理想的工具涂层材料。由于金刚石膜涂层硬质合金工具可能具有金刚石的硬度和硬质合金的强韧性的结合．因此20余年来一直受到世界各国的普遍关注。本文综述了金刚石膜涂层硬质合金的研发历史与现状，并针对目前的市场状况和未来的发展进行了评述。     

镍改性层增强铜基底沉积金刚石膜的形核(英文)

在铜基底溅射约100nm厚的镍改性层,然后置入纳米金刚石悬浮液中超声震荡加载籽晶,随后在热丝化学气相沉积设备中制备出晶体颗粒接近热力学平衡形态的高质量金刚石膜,其中sp2碳相含量低于5.56%。分别采用激光拉曼光谱、扫描电镜与X射线衍射对金刚石膜的形核与生长进行研究。实验结果表明:在溅射有镍改性层的铜基底上,金刚石的形核密度比在无改性层的铜基底上的形核密度高10倍。镍改性层的增强机制主要来源于两个方面:镍改性层的纳米级粗糙表面增强金刚石籽晶颗粒的吸附;镍改性层的强催化效应加速铜基底上金刚石形核生长所需的石墨过渡层的形成,从而促进金刚石的快速形核。