PECVD沉积TiN及其应用

本文介绍了辉光放电等离子体增强气相沉积(PECVD)TiN的设备研制、工艺特点及影响因素。试验结果表明,PECVD克服了CVD、PVD的某些缺点,沉积温度降到650℃以下,TiN涂层的硬度高达HV1800以上,耐磨、耐腐蚀、耐高温氧化,沉积速率快,涂层均匀致密。实际应用效果良好。     

消除PECVD膜的第一晶片效应

本发明大体上提供了用于消除等离子体增强化学气相沉积（PECVD）中“第一晶片效应”的装置和方法。本发明的一种实施例提供了用于在室空闲了一段时间之后使室做好准备的方法。该方法包括在清洁步骤之后,根据空闲时间长度调整进行干燥步骤和加热步骤。     

现代刀具涂层制备技术的研究现状

刀具涂层是一种机床工具行业的重要材料,其性能直接影响数控机床的机械加工精度.概述了刀具涂层材料的特点、要求及涂层制备技术的发展,分析了化学气相沉积法、物理气相沉积法、等离子体增强化学气相沉积法及溶胶-凝胶法等几种涂层制备方法的优缺点.结合国内外刀具涂层的研究现状及发展趋势,指出在大力发展化学气相沉积涂层和物理气相沉积涂层技术的同时,开发两者相结合的新型工艺,推动国内刀具涂层技术的快速发展.     

硬质合金刀具表面化学气相沉积TiC过程的控制

分析了硬质合金刀具化学气相沉积TiC涂层的基本工艺和设备,应用S7-200实现沉积过程反应物流量、温度等参数的可靠控制。应用表明,组建的S7-200控制系统精度高,能实现硬质合金TiC涂层的重复沉积,并通过PLC的程序控制,能较好的复现优质涂层的沉积工艺,实现对硬质合金刀具基体表面质量的改性控制。     

内表面等离子体增强化学气相沉积TiN涂层研究

介绍了一种新型等离子体增强化学气相沉积内表面复合处理系统.利用此系统沉积TiN涂层的结果表明,φ100 mm×1000 mm 316不锈钢管内表面沉积涂层相对均匀,且具有较好的表面特性和机械特性.     

等离子体技术在提高硬质合金工具上金刚石薄膜附着力方面的应用

金刚石薄膜具有优异的性能，作为切削工具表面的保护性涂层，可以大幅度提高工具的使用寿命以及加工精度。硬质合金是一种广泛使用的工具材料，在其表面沉积高附着力的金刚石薄膜时存在着困难。等离子体中离子、原子或分子具有高的反应活性，等离子体技术在金刚石薄膜的制备中有着广泛应用。利用等离子体技术可以极大的消除因金刚石薄膜与硬质合金基体之间存在热应力以及由硬质合金中的钴粘结剂在化学气相沉积金刚石薄膜过程中的促石墨化作用而产生的不利影响，提高金刚石薄膜与硬质合金基底之间附着力。本文综述了等离子体技术在提高硬质合金工具表面金刚石薄膜附着力方面的研究进展。     

化学气相沉积过程中Si的引入对硬质合金金刚石涂层附着力的影响

利用微波等离子体化学气相沉积方法，以H2、CH4和八甲基环四硅氧烷(D4)为原料，在硬质合金基体上沉积了金刚石涂层。与一般只使用H2、CH4为原料时的情况相比，金刚石涂层与硬质合金基体间的附着力有了一定程度的提高。对涂层断面的成分分析表明，Si在涂层与基体间的界面处有富集的倾向，而这将有助于抑制Co对涂层附着力的不利影响，提高金刚石涂层的附着力。     

直流电弧等离子体喷射在金刚石膜制备和产业化中的应用

综述了北京科技大学在直流电弧等离子体喷射CVD金刚石膜沉积系统研制和改进及大面积高质量(包括光学级)金刚石自支撑膜沉积的研究进展和产业化状况.用同样技术研发出了可用于复杂形状硬质合金工具金刚石膜涂层工具批量生产的强电流直流伸展电弧等离子体CVD金刚石膜涂层系统,讨论了利用该设备研发金刚石膜涂层硬质合金工具及其现场切削试验的结果.     

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。     

强电流直流扩展弧金刚石沉积技术的研究

采用自行研制的Q-500金刚石涂层沉积设备,同时采用两种不同结构的等离子体炬对经酸碱二步法处理后的硬质合金钻杆(YF06)分别进行了金刚石涂层的沉积,并对沉积后的样品表面进行了分析和研究.初步的研究结果表明:等离子体炬的结构对金刚石涂层的沉积影响很大,改进前的等离子体炬所产生的弧柱不稳,导致沉积温度波动幅度大,而改进后的等离子体炬能产生稳定的弧柱,沉积温度变化不大并且沉积的金刚石涂层具有大面积、均匀性好和高质量的特点.     

Wear-resistance and hardness: Are they directly related for nanostructured hard materials?

The major challenge in the field of cemented carbides and other hard materials is to obtain their better combination of hardness, wear-resistance and fracture toughness. It is well known that the dependence of abrasion wear on fracture toughness for WC–Co cemented carbides is represented by a relatively narrow band and it is hardly possible to “break away” out from it by the use of conventional approaches based on varying the WC mean grain size and Co content. Also, it is well known that the wear-resistance of conventional cemented carbides depends mainly on their hardness. The major objective of this paper is to establish what will happen with the wear-resistance of hard materials as a result of their nanostructuring when the hardness is nearly the same as for conventional WC–Co cemented carbides. The results obtained provide clear evidence that, if one enters the region of nanostructured materials with the mean grain size of less than 10 nm, traditional wisdom indicating that the wear-resistance is directly related to the hardness appears not to be valid. In some cases of such nanostructured materials, it can be possible to achieve the dramatically improved wear-resistance compared to that of conventional WC–Co cemented carbides at nearly the same level of hardness and fracture toughness. The abovementioned is based on considering hard nanomaterials of the following four types: (1) WC–Co cemented carbides with nanograin reinforced binder, (2) near-nano WC–Co cemented carbides, (3) cemented carbides of the W–C–Cr–Si–Fe system for hard-facing having a nanostructured Fe-based binder, and (4) CVD hard materials consisting of nanostructured W₂C grains embedded in a tungsten metal binder.     

WC-Co-Re cemented carbides: Structure,properties and potential applications

Cemented carbides of the WC-Co-Re system represent a new class of hard materials having a significantly increased Young's modulus, hot hardness and high temperature creep resistance. The WC-Co-Re phase diagram was evaluated and compared with the corresponding WC-Co phase diagram. Physical and mechanical properties of such composites were measured at room and elevated temperatures and compared with those of conventional WC-Co cemented carbides. Microstructures of the WC-Co-Re cemented carbides at different carbon contents, binder contents and WC grain sizes were examined. Rhenium being dissolved in the Co-based binder is found to be a very strong grain growth inhibitor with respect to WC coarsening during liquid-phase sintering. The Young's modulus, hot hardness and high temperature creep resistance of the WC-Co-Re cemented carbides are greater than those of conventional WC-Co cemented carbides. Due to their unique properties the WC-Co-Re materials can find applications in use in high-pressure high-temperature components for synthesis of diamond and c-BN and cutting Ni-based super alloys and other heat-generating workpiece materials.     

喷丸处理硬质合金工艺研究

对喷丸处理硬质合金工艺进行了研究 ,研究表明喷丸处理在硬质合金表层内产生残余压应力和增加应力分布深度 ,该应力及分布有利于提高合金的性能 ,应用该技术处理的顶锤的使用性能提高 30 %以上。     

过渡族金属碳化物在WC-Co硬质合金中的界面偏析与固溶行为

过渡族金属碳化物是最常见的硬质合金微观组织结构与性能调控添加剂,添加剂在硬质合金中赋存状态的研究是WC晶粒生长抑制机理研究的基础,也是硬质合金材料与工艺设计的基础。从基于第一性原理计算的理论研究、基于高分辨透射电镜和原子探针层析法的实验观察分析等2个方面,综述了过渡族金属碳化物在WC/β(钴基固溶体粘结相)相界偏析行为的研究现状。基于过渡族金属碳化物在硬质合金中晶界与相界的偏析行为、在硬质相与粘结相中的固溶行为,讨论了硬质合金中WC晶粒生长机理与晶粒生长抑制机理以及过渡族金属碳化物对硬质合金性能的影响机理,提出了硬质合金材料与工艺设计的建议。     

CSUDDCC1—A diffusion database for multicomponent cemented carbides

Cemented carbides are hard and tough materials for cutting tool, consisting of micrometer-sized carbides embedded in a ductile metal binder phase. In order to increase the performance and extend the service lifetime of the cemented carbides, graded cemented carbides have been developed. The formation of gradient zone during liquid phase sintering is a diffusion-controlled process, and knowledge of diffusivity is indispensable to understand formation mechanism, optimize technological parameters and design a new type of graded cemented carbides. In this paper, a diffusion database for multi-component C–Co–Cr–W–Ta–Ti–Nb–N cemented carbides has been developed through a combination of experiment, theoretical analysis and assessment. The diffusion database contains the atomic mobility parameters for different diffusing elements in liquid and fcc phase. The atomic mobility parameters in liquid phase are theoretically calculated by the newly modified Sutherland equation, and the atomic mobility parameters in fcc phase are optimized by the diffusivities measured in the present work and from the literature. In conjunction with the thermodynamic database for cemented carbides (CSUTDCC1: Central South University Thermodynamic Database for Cemented Carbides—version-1), the diffusion database (CSUDDCC1: Central South University Diffusion Database for Cemented Carbides—version-1) can be used to simulate the gradient sintering process. Simulations of different kinds of graded cemented carbides are presented using the databases and compared where possible against experimental data, in order to validate its accuracy.     

钢结硬质合金的磨料磨损耐磨性

对五种不同成分的钢结硬质合金的磨粉磨损耐磨性在两种不同的磨损条件下进行了系统地研究，分析了各种钢结硬质合金的显微组织，并测定了它们的整体宏观硬度。试验结果表明，钢结硬质合金中碳化物的种类、含量以及钢基体的组织和硬度对其耐磨性均有着显著的影响。碳化物和钢基体的硬度越高以及碳化物的体积分数越大，则钢结硬质合金的耐磨性也越高，工具钢结硬质合金的耐磨性明显高于高锰钢结硬质合金的耐磨性。     

硬质合金的疲劳与断裂

硬质合金在使用中一般同时承受多重疲劳的共同作用,了解硬质合金的疲劳破坏机理和提高其疲劳性能是硬质合金研究领域的一个重要方向。综述各种硬质合金工具在不同环境中的疲劳破坏情况,概括目前国内外学者对硬质合金疲劳性能的机理的研究进展。同时介绍本课题组在自行改造的疲劳试验机上对硬质合金多重疲劳开展的一些工作。     

Preparation of Co powders for cemented carbides in China

Cobalt has been used as a supreme binder in cemented carbides. As the largest production nation of cemented carbides in the world, large amounts of cobalt powders, about 1200 tons in 2005, are consumed in China market. It is known that many factors, both in terms of composition and processing techniques, affect cemented carbides properties that are correlative with the ingredient, particle size, particle shape and microstructure of the cobalt powders. The studies on preparation of Co powders for cemented carbides in China are reviewed in this paper. The fabrication method, particle size and shape of cobalt powders are described and discussed according to the processing techniques. The typically chemical and physical properties of cobalt powders in Chinese production are introduced briefly. In order to further improve the cemented carbides quality, more research works on the microstructure and composition of doped alloying elements cobalt powders should be made in China in future.     

Cemented carbide microstructures: a review

Cemented carbides cover a wide range of applications in many relevant industries, i.e. as cutting tools (turning, milling, drilling) for machining of metal components in the automotive and/or aerospace industry, as components of drill bits or road headers in the rock tools and mining area or as wear parts in wire drawing dies or punch tools. In this review selected cemented carbide and cermet microstructures are presented. The focus is on microstructures, both those that are already established in the cemented carbide industry and those which have drawn scientific attention due to new potential applications. Cemented carbides are here divided in four groups based on microstructure and chemistry: WC morphology and chemistry, cubic carbide containing cemented carbide and cermets, functionally graded cemented carbides, and binder design of cemented carbides. Furthermore, this review covers some historical background that motivated the microstructure design as well as the status of each class of materials nowadays. The paper aims at categorising cemented carbides in a structured way and to serve as an introduction to cemented carbide microstructures for engineers, researchers and scientists.     

Characterization and properties of MTCVD Ti(C,N) coated cemented carbide substrates with Fe/Ni binder

Two developments, including the deposition of hard chemical vapour deposition (CVD) coatings on cemented carbides and the use of innovative binders instead of Co for cemented carbides, have attracted worldwide interest. In this paper, ISO grade P30 cemented carbides with Fe/Ni and Co binders are prepared as the substrates, and adherent Ti(C,N) coatings are deposited on them by moderate temperature chemical vapour deposition (MTCVD) technique. The microstructure and properties of both the substrates and coated cemented carbides are studied.