甲烷浓度对批量生产金刚石涂层刀片的影响

采用微波等离子体CVD(MWCVD)法小批量地生产了金刚石涂层刀片,在金刚石薄膜沉积的过程中,研究了碳源浓度对沉积金刚石膜的均匀性的影响。用扫描电子显微镜(SEM)和激光拉曼光谱(Raman)对薄膜的表面形貌和质量进行了表征。结果表明较低的低甲烷浓度适合金刚石涂层刀片的批量生产。     

正偏压对微波等离子体CVD法制备金刚石薄膜的影响

线形同轴耦合式微波等离子体CVD法是在硬质合金微型钻头(微钻)表面沉积金刚石涂层的最佳方法之一.本文首先研究了酸碱两步预处理后微钻表面的形貌和成分,然后研究了微钻工作表面金刚石的沉积情况,最后重点研究了正偏压对微钻不同位置金刚石生长的影响.结果表明,在微钻上施加50 V正偏压时,金刚石薄膜具有最佳的形貌和较好的均匀性.     

微波CVD金刚石薄膜用作LED散热片的制备

由于金刚石具有室温下最高的热导率,因此用化学气相沉积(CVD)制备的金刚石膜是大功率发光二极管(LED)理想的散热材料.本文利用微波等离子体CVD研究了不同沉积工艺下金刚石薄膜的生长.用扫描电子显微镜(SEM)和拉曼光谱对得到的金刚石薄膜进行了表征,并将金刚石薄膜用作LED散热片的散热效果进行了检测.结果表明:在硅衬底上沉积20-30μm的CVD金刚石薄膜可以有效地降低LED的工作温度;在相同的制备成本下,提高薄膜的厚度(甲烷浓度4%)比提高薄膜的质量(甲烷浓度2%)更有利于提高LED的散热效果.本研究表明微波等离子体CVD制备的金刚石薄膜是大功率LED的理想散热衬底材料.     

低表面粗糙度金刚石涂层刀具的制备

降低表面粗糙度是改善金刚石涂层刀具使用性能的有效手段.采用微波等离子体化学气相沉积(MPCVD)金刚石膜,通过在沉积过程中调整工艺参数,先后在硬质合金基体上沉积了2层不同的金刚石薄膜.研究了基体位置、甲烷浓度等对薄膜表面形貌的影响.用扫描电子显微镜(SEM)、原子力显微镜(AFM)和压痕法对样品进行了分析测试,结果表明,该方法在保证金刚石涂层质量的同时有效降低了薄膜表面的粗糙度,表面粗糙度值Ra＜0.2 μm.     

微型硬质合金钻头上金刚石涂层研究

WC-Co硬质合金钻头经过短时间酸腐蚀和微波等离子体硼氮化处理后,利用热丝CVD方法生长金刚石薄膜,并在电路板和玻璃板上进行了附着力测试.研究表明:钻头垂直于热丝放置,钻头端部为最高硬度的(111)面,有利于改善钻头切削加工性能;短时间酸腐蚀只去掉了钻头表面的钴,不降低表面硬度.同时酸腐蚀手段提高了表面粗糙度,避免了在随后的硼氮化处理时在WC表层形成低附着力的硼化物层,提高了金刚石薄膜附着力.在电路板及玻璃板上钻孔的测试结果表明,金刚石薄膜涂层钻头具有更高的寿命.     

YG6金刚石涂层刀片衬底真空渗硼预处理新技术研究

本文研究了真空渗硼预处理硬质合金基体的表面组织、形貌、粗糙度，并在处理过的YG6刀片基体上，用强电流直流伸展电弧等离子体CVD法沉积金刚石薄膜涂层。结果表明，真空渗硼预处理不仅可以有效的消除或控制钴在金刚石沉积时的不利影响，而且，还显著粗化硬质合金基体表面。因此，提高了金刚石薄膜的质量和涂层的附着力。     

硬质合金工具强电流直流伸展弧等离子体CVD金刚石涂层的均匀性研究

采用自行研制的强电流直流伸展电弧等离子体CVD设备对真空渗硼预处理的YG6刀片进行了金刚石涂层沉积，并对放于有效沉积区域不同位置沉积出的金刚石涂层刀片以及刀片自身不同位置之表面涂层的形貌、厚度、质量进行了分析、研究。结果表明：(1)、硬质合金工具强电流直流伸展弧等离子体CVD金刚石涂层的组织、形貌、厚度、质量都是均匀一致的。(2)、利用强电流直流伸展电弧等离子体CVD设备可进行硬质合金金刚石涂层的批量沉积。     

CN1632165一种在硬质合金工具上制备金刚石涂层的方法

本发明提供了一种在硬质合金工具上制备金刚石涂层的方法。采取等离子体CVD技术，由含有氢、碳和硅元素的气体混合物为反应气体，在硬质合金工具上沉积含有金刚石相和硅的金刚石涂层；其中，硅是在金刚石涂层的CVD过程进行的同时，被沉积到金刚石涂层中以及金刚石涂层与硬质合金工具的界面处的；硅元素在金刚石涂层与硬质合金工具界面处的存在与富集使金刚石涂层对硬质合金工具形成高的附着力。所述的CVD技术包括：微波等离子体CVD技术、热丝CVD技术、直流电弧等离子体CVD技术。本发明的优点在于：有效地提高金刚石涂层的附着力并简化了涂层的制备工艺。     

利用热等离子体CVD工艺合成大面积金刚石薄膜

CVD金刚石可以用各种方法合成，其中晶粒生长速度最快的则为热等离子体CVD工艺。我们试验室过去曾试图用DC等离子体CVD工艺合成金刚石厚膜，并就膜与基底的附着强度和膜的性质作过探讨。但是，热等离子体工艺存在沉积面积和膜质量都不如其它CVD工艺等问题。CVD金刚石薄膜应用中对扩大沉积面积有着强烈的需求。本研究试图通过控制沉积压力、输入功率等沉积参数扩大等离子体直径，以沉积出大面积金刚石薄膜。我们的目的是利用热等离子体CVD工艺沉积出生长速度高、面积大且膜厚均匀的金刚石薄膜。同时探讨了合成条件对金刚石薄膜形状的影响。本研究得出的结果如下：(1)随着沉积压力的降低，金刚石晶粒尺寸减小，成核密度增加。金刚石的结晶性则几乎不受沉积压力的影响。(2)随着等离子体电流的增加，金刚石晶粒尺寸减小，成核密度增加。增加等离子体电流也可改善金刚石的结晶性。(3)降低沉积压力和增加等离子体电流均可扩大等离子体射流，但是金刚石沉积面积的变化并不明显。(4)随着沉积压力的降低和等离子体电流的增加，金刚石的结晶性均会增加。降低沉积压力和增加等离子体电流有利于改善金刚石薄膜的均匀性。     

微波等离子体刻恂对WC—Co硬质合金基体金刚石薄膜附着力的影响

金刚石薄膜的附着力是影响CVD金刚石涂层刀具切削性能的关键因素,本文采用EACVD法在硬质合金（YG6）基体上沉积金刚石涂层;用Ar-H2微波等离子WC－C0衬底进行刻蚀处理,以改变基体表面与金刚石涂层间的界面结构,提高金刚石涂层的附着力;采用压痕法评估涂层附着力,借助SEM等观察刻蚀预处理方法对膜基界面的影响,并对此进行分析和讨论。     

加工氧化锆陶瓷的金刚石涂层刀具的制备及切削试验研究

使用热丝化学气相沉积法(HFCVD)在硬质合金片以及球头铣刀表面沉积了微米金刚石薄膜(MCD),纳米金刚石薄膜(NCD)以及微米纳米复合金刚石薄膜(MNCD),通过扫描电子显微镜和拉曼光谱对其进行表征,结果呈现出典型的金刚石薄膜的性质,沉积质量高。金刚石薄膜与氧化锆陶瓷的摩擦磨损实验表明:金刚石薄膜能有效地降低对磨时的摩擦系数以及磨损率。使用三种金刚石薄膜涂层铣刀对氧化锆陶瓷进行铣削加工试验,结果显示:金刚石涂层刀具磨损率大幅度降低,刀具寿命显著增强。     

金刚石涂层拉拔模具的制备与性能研究

本文通过在硬质合金基体表面沉积金刚石膜,制作了金刚石涂层拉拔模具。金刚石压痕仪测试显示,涂层的抗压能力达1.5 kN。扫描电镜和原子力显微镜观察结果表明,涂层颗粒的平均尺寸为0.1μm,加工后的粗糙度Ra0.1μm。用于拉制焊接金属丝和不锈钢丝,使用寿命达硬质合金模具的15~50倍。分析了金刚石涂层具有超强耐磨损能力的原因,并对该种模具的失效机理进行了初步研究。     

CVD金刚石涂层煤液化减压阀关键部件的制备

煤液化减压阀的工作条件非常苛刻,对其阀座、阀芯等关键部件在高温、高压差、高固态浓度流体冲蚀条件下的抗冲蚀磨损性能及使用稳定性提出了极高的要求.CVD金刚石涂层具有接近天然金刚石的优异性能,非常适合用于煤液化减压阀关键部件的表面强化.采用热丝CVD法在硬质合金阀座及阀芯主要的受冲蚀表面沉积获得了金刚石涂层,为保证沉积过程...     

Analyzing the performance of diamond-coated micro end mills

A method is presented to improve the tool life and cutting performance of 300 μm diameter tungsten carbide (WC) micro end mills by applying thin (<300 nm) fine-grained diamond (FGD) and nanocrystalline diamond (NCD) coatings using the hot-filament chemical vapor deposition (HF-CVD) process. The performance of the diamond-coated tools has been evaluated by comparing their performance in dry slot milling of 6061-T6 aluminum against uncoated WC micro end mills. Tool wear, coating integrity, and chip morphology were characterized using SEM and white light interferometry. The initial test results show a dramatic improvement in the tool integrity (i.e., corners not breaking off), a lower wear rate, no observable adhesion of aluminum to the diamond-coated tool, and a significant reduction in the cutting forces (>50%). Reduction of the cutting forces is attributed to the low friction and adhesion of the diamond coating. However, approximately 80% of the tools coated with the larger FGD coatings failed during testing due to delamination. Additional machining benefits were attained for the NCD films, which was obtained by using a higher nucleation density seeding process for diamond growth. This process allowed for thinner, smaller grained diamond coatings to be deposited on the micro end mills, and enabled continued operation of the tool even after the integrity of the diamond coating had been compromised. As opposed to the FGD-coated end mills, only 40% of the NCD-tools experienced delamination issues.     

Carbon doped α-Al2O3 coatings grown by chemical vapor deposition

Alumina (Al₂O₃) coatings deposited by chemical vapor deposition (CVD) with different modifications and dopants are widely applied as wear resistant coatings on cemented carbide cutting tools. The aim of this work was to investigate the influence of CH₄ addition on the deposition of α-Al₂O₃ by low-pressure chemical vapor deposition (LPCVD). The coatings were deposited at 1005 °C on a TiN–TiCN base layer using a precursor gas mixture of AlCl₃, CH₄, CO₂, HCl, H₂S, and H₂. Coating characterization was conducted by scanning electron microscopy (SEM), glow discharge optical emission spectroscopy (GDOES), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), glancing angle X-ray diffraction (GAXRD), nanoindentation and tribological ball-on-disk tests against Al₂O₃ balls. Additionally, the ball-on-disk wear tracks were investigated by Raman spectroscopy.     

Diamond-coated cutting tools for biomedical applications

Diamond coatings are attractive for cutting processes due to their high-hardness, low-friction coefficient; excellent wear resistance, and chemical inertness. The application of diamond coatings on cemented, tungsten carbide (WC-Co) burs has been the subject of much attention in recent years as a method to improve cutting performance and tool life. WC-Co burs containing 6% Co and 94% WC substrate, with an average grain size of 1–3 μm, were used in this study. To improve the adhesion between diamond and WC substrates, it is necessary to etch away the surface Co and prepare the surface for subsequent diamond growth. Hot filament chemical vapor deposition (HFCVD), with a modified vertical filament arrangement, has been used for the deposition of diamond films. Diamond film quality and purity has been characterized using scanning electron microscopy (SEM) and micro-Raman spectroscopy. The performance of diamond-coated WC-Co burs, uncoated WC-Co burs, and diamond-embedded (sintered) burs have been compared by drilling a series of holes into various materials such as human teeth, borosilicate glass, and acrylic teeth. Flank wear has been used to assess the wear rates of the burs when machining biomedical materials such as those just described. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 273–82 of the Proceedings.     

衬底位置对制备（100）面金刚石薄膜的影响

本文利用5kW微波等离子体装置,在直径22mm的石英上沉积金刚石薄膜。实验研究了衬底在不同位置对沉积金刚石薄膜的质量产生的影响。实验中将2块石英衬底编号为A和B,样品A被放在偏离钼基片台中心5mm的位置,使石英的中间区域偏离等离子体球,而边缘区域处于等离子体球的下方。通过SEM和拉曼光谱表征所沉积的金刚石膜,对比样品A的中间和边缘区域发现中间的区域金刚石膜的质量差且不均匀,边缘区域则长出取向一致的（100）面金刚石。通过分析认为,较高的温度、大的等离子体密、合适的碳源浓度度等条件有利于（100）面金刚石薄膜的沉积。随后改进工艺,将样品B放在基片台中心使其处于等离子体的正下方,并调整生长温度和甲烷浓度,成功的获得了高质量均匀的（100）面金刚石薄膜。     

热丝化学气相沉积法制备优质微米亚微米级单晶金刚石的研究

利用热丝化学气相沉积法（HFCVD）,在硅片衬底上进行微米级（〉1μm）及亚微米级（〈1μm）单晶金刚石的沉积研究。微米级金刚石是以高温高压法（HPHT）制备的1μm金刚石颗粒为籽晶,通过甩胶布晶的方法,在衬底上均匀分布晶种,并通过合理控制沉积工艺参数,在衬底上形成晶形完好的单晶金刚石。在沉积2 h后,可消除原HPHT籽晶缺陷,沉积6 h后,生长出晶形良好的立方八面体金刚石颗粒（约4μm）;对于亚微米级单晶金刚石,是直接在衬底上进行合成,通过调控沉积参数（如衬底预处理方法,偏流大小,沉积时间）对单晶金刚石的分布密度和颗粒度进行控制,经过2 h的沉积,最终获得了0.7μm的二十面体单晶金刚石。     

碳源浓度对金刚石薄膜涂层刀具性能的影响

用热丝ＣＶＤ法,以丙酮为碳源,在ＷＣ－Ｃｏ硬质合金衬底上沉积金刚石薄膜,研究了碳源浓度对金刚石薄膜涂层刀具性能的影响,结果表明,碳源浓度对金刚石涂层薄膜质量、形貌和粗糙度、薄膜与衬底间的附着力、刀具的耐用度用度发削性能有显著影响,合理控制碳源浓度对获得实用化的在硬质合金刀具基础上沉积高附着强度、低粗糙度金刚石薄膜的新技术具有重要的意义。     

Mechanism and prediction of failure of diamond films deposited on various substrates by HFCVD

Diamond films were deposited on the WC-Co cemented carbide and Si3N4 ceramic cutting tool substrates by hot-filament-assisted chemical vapour deposition. The adherence property of diamond films was estimated using the critical load (Pcr) in the indentation test. The adhesive strength of diamond films is related to the intermediate layer between the film and the substrate. Poor adhesion of diamond films to polished cemented carbide substrate is owing to the formation of graphite phase in the interface. The adhesion of diamond films deposited on acid etched cemented carbide substrate is improved, and the peeling-off of the films often happens in the loosen layer of WC particles where the cobalt element is nearly removed. The diamond films' adhesion to cemented carbide substrate whose surface layer is decarbonizated is strengthened dramatically because WC phase forms by reaction between the deposited carbon and tungsten in the surface layer of substrates during the deposition of diamond, which results in chemical combination in the film-substrate interface. The adhesion of diamond films to silicon nitride substrate is the firmest due to the formation of chemical combination of the SiC intermediate layer in the interfaces. In the piston-turning application, the diamond-coated Si3N4 ceramic and the cemented carbide cutting tools usually fail in the form of collapsing of edge and cracking or flaking respectively. They have no built-up edge(BUE) as long as coating is intact.As it wears through, BUE develops and the cutting force on it increases 1 - 3 times than that prior to failure. This can predict the failure of diamond-coated cutting tools.