磨损条件对碳化钨基复合涂层性能的影响

通常,在油砂开采过程中,标准合金不具备在磨损和腐蚀条件下抗磨损性能。对于生产性关键组件,通常采用碳化钨基复合涂层(MMC)来延长设备寿命,防止非计划性停运。复合涂层的性能主要依赖磨损环境。本文将对碳化钨基复合涂层在不同的研磨条件下的机械性能和结构性能进行研究,探讨这种交互作用如何在决定性能等级上起到关键作用。这些信息会为更好的选材提供依据,甚至可延长零部件的寿命。     

磨损条件对碳化钨基复合涂层性能的影响

通常,在油砂开采过程中,标准合金不具备在磨损和腐蚀条件下抗磨损性能。对于生产性关键组件,通常采用碳化钨基复合涂层(MMC)来延长设备寿命,防止非计划性停运。复合涂层的性能主要取决于磨损环境。本文将对碳化钨基复合涂层在不同的研磨条件下的机械性能和结构性能进行研究,探讨这种交互作用如何在决定性能等级上起到关键作用。这些信息会为更好的选材提供依据,乃至拓展零部件的寿命。     

西德克虏伯.维迪阿生产的新型刀具

西德克虏伯·维迪阿推出了各种新型切削刀具和切削刀具材料。这些包括采用两种新型金属陶瓷牌号制成的非涂层刀具,在新型碳化钨基上使用新一代涂层的涂层刀具,并还推出了金属成型刀具的新型牌号。     

难熔钨基合金的研究开发及其产业化方向

综述了难熔钨基合金的研究与开发现状及发展趋势;分析了难熔钨基合金的市场应用前景;并指出日趋成熟的新技术和新工艺,包括金属注射成形和挤压成形技术以及纳米复合粉末和细晶难熔钨合金的制备技术,必将成为21世纪难熔钨基合金的研究开发与高利润产品产业化方向.     

难熔钨基合金的研究开发及其产业化方向

综述了难熔钨基舍金的研究与开发现状及发展趋势；分析了难熔钨基合金的市场应用前景；并指出日趋成熟的新技术和新工艺，包括金属注射成形和挤压成形技术以及纳米复合粉末和细晶难熔钨合金的制备技术，必将成为21世纪难熔钨基合金的研究开发与高利润产品产业化方向。     

碳化钨-抑制剂复合粉末及其超细硬质合金的制备方法

该发明涉及一种碳化钨-抑制剂复合粉末及其超细硬质合金的制备方法。首先制备含碳和抑制剂的氧化物粉末,然后采用直接还原碳化法合成碳化钨-抑制剂复合粉末．添加金属粉末后进行球磨混合、干燥、成型、真空烧结或氢气烧结后热处理,或直接低压烧结,得到超细或纳米碳化钨基硬质合金。该发明解决了已有技术存在抑制剂后期添加不均匀或抑制剂在前期添加时只能采用碳化温度低的抑制剂的缺陷。可使多种抑制剂在前期引入并保证其在碳化钨基体中的均匀分散,所用原料都采用环保性化合物,制备温度低于传统制备方法,工艺简捷安全,生产成本低,易实现产业化。     

WC-Co(Cr)超音速火焰喷涂粉末和涂层性能

采用喷雾造粒和真空烧结工艺制备粒度15~45μm的WC-12%Co(WC12Co)、WC-17%Co(WC17Co)、WC-10%Co-4%Cr(WC10Co4Cr)球形喷涂粉末,并采用超音速火焰喷涂(HVOF)法在同一喷涂参数下制备WC12Co,WC17Co,WC10Co4Cr涂层,应用金相显微镜、X-射线衍射仪、扫描电镜、显微硬度计等表征粉末和涂层的结构和性能。结果表明:制备的3种碳化钨基喷涂粉末球形度高,流动性好(~13s/50g),松装密度接近(4.8~5.0 g/cm3),粉末物相均为WC和Co相,各粉末微观结构和物理性能均满足液体燃料HVOF喷涂要求;3种粉末制备的涂层的沉积率高(52%~55%)、孔隙率低(1.1%)、显微硬度高(1200~1 300 HV300g);各涂层脱碳程度小,涂层物相均为WC、W2C和非晶或纳米晶相;相同喷涂工艺下WC17Co、WC12Co、WC10Co4Cr涂层的耐磨粒磨损性能依次增强,同时WC10Co4Cr涂层具有较强的耐盐雾腐蚀性能。     

高性能细晶钨基复合材料制备关键技术及开发应用

钨基复合材料具有密度高、熔点高、强度高、热膨胀系数小、热导率高、抗辐射能力强、耐腐蚀性强等优点,在电子信息、机械加工、航天航空、国防军工和核工业等领域可广泛用作穿破甲材料、电子封装材料、电极材料以及核辐射屏蔽材料等。采用传统方法制备的钨基复合材料由于晶粒粗大、组织均匀性差、性能低或致密度低等缺陷,已经难以满足尖端技术领域的发展需要。采用纳米复合技术制备的细晶钨基复合材料具有致密度高、组织细小且均匀、性能好等优点,成为钨基复合材料发展的重要方向。概述了高性能细晶钨基复合材料的制备关键技术与开发应用,并对高性能细晶钨基复合材料的应用前景作出了展望。     

纳米碳化聚合物的制备、性质及应用

纳米碳化聚合物作为一种新型的碳纳米材料引起了人们广泛的关注。纳米碳化聚合物具有独特的核壳结构（sp2/sp3组成碳核,聚合物链、官能团构成壳）,学者们通过调控反应条件以获得预期的纳米碳化聚合物结构,并将其广泛应用于生物成像、传感器、催化、发光二极管、铜基复合材料等领域。本文分析讨论了纳米碳化聚合物的结构、合成方法、形成机理、主要性质及应用,介绍了该同素异构体在材料、尤其是粉末冶金材料中的最新研究成果,最后对纳米碳化聚合物未来的发展进行展望。     

合肥物质科学研究院在高性能纳米晶钨基合金研制方面取得进展

正近期,中国科学院合肥物质科学研究院固体物理研究所研究员方前锋课题组在纳米结构钨基合金研制方面取得新进展,通过压力辅助低温致密化烧结法成功制备出高强度双纳米结构钨材料。钨基合金被认为是最有潜力的能够应用于聚变反应堆极端环境的面向等离子体第一壁材料,但商业纯钨的脆     

Phase Composition of Electrospark Tungsten Carbide-Based Coatings after Heating and Isothermal Soaking

A study of phase formation on electrospark coatings with WC Co Cu electrodes on R6M5 high-speed steel during isothermal heat treatment at the operating temperature of the coating. Copper tungstate CuWO ₄has been found to form, with its crystal lattice coherently bound to the basic carbide phase of the coating, tungsten monocarbide, through tungsten semicarbide as intermediary. The results complement the data on phase formation during the application of WC-based coatings and during their subsequent use with sliding friction.     

HVOF喷涂Cr3C2-NiCr涂层：粉末颗粒形貌和喷涂参数对涂层微观组织、性能和高温耐磨性的影响

热喷涂碳化铬涂层广泛应用于高温耐磨环境。在这样高温的恶劣环境下,许多相会产生分解、氧化以及涂层组织变化,从而影响其耐磨性。尽管可以认为Cr3C2-NiCr涂层在高温条件下的组织分解将取决于喷涂微观结构和喷涂参数,但在这方面的研究较少。本文旨在设计出更好的喷涂参数,以提高碳化铬涂层在高温滑动磨擦磨损条件下的显微结构性能。通过X-射线衍射（XRD）和扫描电子显微镜（SEM）观察两种Cr3C2-NiCr相所形成的涂层组织,并且观察飞行颗粒的温度和速度。本文研究了800％下滑动摩擦行为与喷涂参数和涂层微观结构的关系,同时测量涂层在滑动磨擦前后的维氏硬度（300gf）。     

超细及纳米WC-Co复合粉的低成本短流程制备及应用

综述了在超细及纳米WC-Co粉末的制备研究方面国内外的相关研究进展,系统介绍了北京工业大学硬质合金研究组在研究开发超细及纳米WC-Co复合粉的原位反应合成技术、超细及纳米复合粉在金属陶瓷防护涂层及烧结硬质合金块体材料中的应用等方面开展的系列工作和取得的研究结果。以合成的WC-Co复合粉为原料,制备的超细结构硬质合金涂层、超细晶及纳米晶硬质合金块体材料均具有优良的综合性能。     

Structural investigations of detonation-deposited tungsten carbide-cobalt coatings

Conclusions The phase composition of detonation-deposited VK type coatings differs from that of the starting mixtures. A deposited layer contains about 40–50% of the tungsten carbide WC present in the starting mixture, metallic tungsten and cobalt, the intermetallic compounds Co₇W₆ and Co₃W, traces of W₂C, and a small amount of complex carbides. The amount and particle size of the tungsten carbide in a coating are determined by the particle size distribution of the powder being deposited and detonation process parameters. Our investigations have shown that the optimum powder particle size range for the process of detonation deposition of hard-metal mixtures may be taken to be 5–40 m. During detonation deposition under the conditions investigated the usual hard-metal structure and composition are not obtained. Most of the starting tungsten carbide decomposes with the formation of tungsten and cobalt intermetallic compounds. Attempts should now be made to improve deposition conditions so as to increase the phase and structural homogeneity of layers being deposited. In coatings deposited by an optimum method the ductile Co binder will be present in an amount close to that in a sintered VK type hard metal. The fracture of coatings and basis metal on the antivibration shelves of compressor blades has a fatigue character. Crack initiation takes place in the surface and inner layers of detonation-deposited coatings as a result of their considerable brittleness, which is due to the presence of metastable intermetallic phases as well as of defects in the form of pores and blowholes.Translated from Poroshkovaya Metallurgiya, No. 10(238), pp. 24–29, October, 1982.     

超音速等离子喷涂制备WC-Co涂层的技术经济分析

介绍了应用自行开发的高效能超音速等离子喷涂技术(HEPJet)制备WC-12Co涂层的一些性能与技术特点,并与APS和目前应用较多的超音速火焰(HVOF)喷涂方法进行了技术经济对比分析。结果表明HEPJet制备的WC-Co涂层中WC的分解和失碳现象较APS显著改善,而涂层的氧化低于HVOF,使涂层的性能优于APS,与HVOF相当;另一方面由于HEPJet制备WC-Co涂层的沉积效率高,能耗低,综合喷涂成本下降,显示出良好的技术经济特色。     

Coating of graphite fibers with tungsten carbide using solid and liquid copper as a transfer medium

An attempt was made to coat graphite fibers with tungsten carbide. Solid and liquid copper were used as a diffusion medium for tungsten to migrate to the surface of the graphite fibers at elevated temperature to form carbides. It was found that it is possible to electroplate Cu-1 pct W alloy on graphite fibers. It was established that this alloy contained tungsten in atomic dispersion. It was fur-ther discovered that tungsten was not in an equilibrium condition in copper and upon heat treatment formed fine precipitates instead of diffusing to the surface of the fiber to form tungsten carbide. However, it was also found that tungsten has a certain solubility in liquid copper and thus it was possible to obtain carbide coatings on graphite fibers by using liquid copper as a transfer agent for tungsten.     

Ceramic-Metal Composite Coating by Laser Cladding

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石墨烯对激光熔覆镍基碳化钨涂层组织及性能影响

采用激光熔覆技术在Q235钢基体上制备Ni60A-30%WC-x%石墨烯(质量分数, x=0.0, 0.1, 0.3, 0.5)涂层, 研究石墨烯对激光熔覆镍基碳化钨涂层组织与性能的影响。结果表明, 涂层物相主要由具有γ相结构的Ni-Cr-Fe固溶体、WC、W₂C、Cr₇C₃、Cr₂₃C₆、B₄C等组成; 石墨烯改善了激光熔覆镍基碳化钨涂层的组织, 提高了涂层的硬度和抗摩擦磨损性能; 当石墨烯质量分数为0.3%时, 得到了析出相分布均匀且细小的组织, 涂层具有高硬度、良好的抗裂纹扩展能力和耐磨性。     

High-temperature electrometallurgical synthesis of tungsten and molybdenum carbides

Compositions of the products of the electrolysis of melts based on a eutectic mixture of sodium chloride-lithium fluoride and sodium tungstate, which contains molybdenum(VI) and tungsten(VI) oxides, molybdates, tungstates, and carbonates of lithium or sodium, are investigated. It is shown that, depending on the content of melt components, the products of electrolysis are carbon, molybdenum, tungsten, and their bronzes and carbides. The conditions of the deposition of galvanic coatings of molybdenum and tungsten carbides on carbon, nickel, and copper matrices are determined.     

A Review on Die Attach Materials for SiC-Based High-Temperature Power Devices

Recently, high-temperature power devices have become a popular discussion topic because of their various potential applications in the automotive, down-hole oil and gas industries for well logging, aircraft, space exploration, nuclear environments, and radars. Devices for these applications are fabricated on silicon carbide-based semiconductor material. For these devices to perform effectively, an appropriate die attach material with specific requirements must be selected and employed correctly. This article presents a review of this topic, with a focus on the die attach materials operating at temperatures higher than 623 K (350 °C). Future challenges and prospects related to high-temperature die attach materials also are proposed at the end of this article.