共查询到19条相似文献,搜索用时 77 毫秒
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原料粉末粒径匹配对放电等离子烧结制备的超细WC-Co硬质合金性能的影响 总被引:1,自引:0,他引:1
采用亚微米WC粉和纳米Co粉以及亚微米WC粉和微米Co粉的混合粉末作为原料,利用放电等离子烧结(SPS)技术制备超细晶WC-10Co硬质合金.对比研究表明,以两种混合粉末为原料均获得了平均晶粒尺寸约为200 nm的超细硬质合金材料.其中,采用微米Co粉制备的材料的相对密度达到98.0%以上,硬度HRA达到94.5,断裂韧性达到13.50 MPa·m1/2,具有优良的综合性能;而采用纳米Co粉制备的硬质合金的组织均匀性和性能较差.根据SPS技术的烧结机理,对混合粉末的致密化机制进行了分析. 相似文献
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超细Cr_3C_2粉末的制备 总被引:1,自引:0,他引:1
将CrO3溶解于有机溶液中,通过喷雾干燥制得非晶态含铬的粉末前驱体,将前驱体粉末真空还原/碳化后得到超细Cr3C2粉末。采用X射线衍射仪﹑扫描电镜对工艺过程进行分析,分析结果表明:前驱体为10μm~20μm非晶态球形粉末,在真空中当温度升高到400℃时,前驱体粉末开始分解,生成微晶Cr2O3。当温度升高到550℃时,微晶Cr2O3迅速长大,前驱体粉末全部转变为Cr2O3与游离C原子级别混合均匀的复合粉末;温度升高到1150℃时得到碳化完全的Cr3C2粉末,粉末的一次颗粒粒度为0.5μm左右。 相似文献
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以氧化钻(Co3O4)、过渡金属氧化物(V2O5、Ta2O5、MoO3、TiO2)和碳粉(C)为原料,用真空直接还原碳化技术制备了应用于硬质合金的钻.抑制剂(Co-VC、Co-TaC、Co-Mo2C、Co-TiC)超细复合粉末。用XRD分析了不同反应温度和时间下生成物的相组成,用SEM观察了复合粉末的形貌。结果表明:直接还原碳化技术能使钻.抑制剂超细复合粉末在较低温度下合成,钻的添加能有效降低过渡金属氧化物的碳化温度。通过对比实验和热力学探讨了低温碳化的机理。 相似文献
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超细WC-Co硬质合金的制备与性能研究 总被引:5,自引:4,他引:1
利用高能球磨法制备纳米级WC-Co混合粉末,采用脉冲电流烧结技术进行烧结。用能谱分析仪(EDX)对球磨后的粉末进行成分分析,用X射线衍射(XRD)对比分析球磨前后WC-Co混合粉末的衍射峰变化,用透射电子显微镜(TEM)和扫描电子显微镜(SEM)对所制备的粉末及烧结材料进行了组织形貌观察,并测定了烧结试样的硬度。结果表明:随着球磨时间的延长,WC-Co纳米粉末的粒度逐渐变小,当球磨时间超过30h后获得了粒度为100nm以下的WC-Co纳米粉末。脉冲电流烧结后获得超细WC-Co硬质合金,与传统的WC-Co硬质合金相比,超细WC-Co硬质合金具有更高的硬度(HRA92.5~94)和耐磨性。另外通过实验获得了最佳的烧结工艺参数。 相似文献
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采用一个新工艺来处理天然钛铁矿并制备高品位的人造金红石纳米颗粒.该工艺主要包括球磨、碳热还原和盐酸浸出步骤.天然钛铁矿通过球磨处理后,颗粒尺寸会大幅度减小;后续的碳热还原会导致高钛渣的形成.在盐酸浸出工序中,重点考察了酸浸时间、温度和酸的浓度对浸出过程的影响.通过优化工艺条件,最后所得到的产品为纯度超过98.0%、颗粒尺寸为10~200nm的TiO2纳米颗粒. 相似文献
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超细WC-Co硬质合金复合粉末的研究进展 总被引:1,自引:2,他引:1
超细硬质合金因其高强度、高硬度、高耐磨性等优良性能满足了现代工业的发展,而制备超细WC-Co硬质合金关键技术之一在于原料粉末的制备。近年来,研究人员开发了多种超细WC-Co复合粉末的制备技术,有利于制备出具有超细结构的WC-Co合金材料。本文介绍、归纳了目前国内外直接还原碳化法、化学沉淀法、机械合金化法、喷雾转化法的制备超细WC-Co复合粉末工艺及研究成果,其中喷雾干燥法和直接还原碳化法已在硬质合金行业中实现部分产业化,具有诱人的应用前景。 相似文献
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E V. Krakhmalev 《中国有色金属学会会刊》2007,17(6):1287-1293
Abrasive wear of a series of WC-(5%-14%, mass fraction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used. The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage. This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive. 相似文献
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The principles underlying composite material behavior during metallographic preparation of coating cross-sections are generally
not well understood. This study of the effect of extended fine polishing on apparent porosity shows that adequate polishing
times, using a fine abrasive (3 μm) and low force, are required to remove prior deformation in the section surface and to
reveal the true porosity of the underlying composite material. Insufficient polishing times can result in considerable underestimation
of porosity. A model is described which proposes that the deformation induced in the material during grinding and polishing,
even at low applied force, results in smearing of material into voids that exist in the plane of the section. 相似文献
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超音速火焰喷涂碳化钨-钴涂层磨粒磨损行为 总被引:1,自引:0,他引:1
采用超音速火焰喷涂工艺在16Mn钢上制备了WC-12Co涂层,并测试了该涂层的力学性能特别是其抗磨粒磨损性能。结果表明:WC-12Co涂层的主相为碳化钨,显微硬度为(1341.0±134.3)HV,孔隙率为0.21%±0.04%。该涂层的磨损率随着磨粒硬度、磨粒粒度和加载载荷的增加而增加。当磨粒的硬度低于涂层硬度时,涂层的磨损机制以磨耗磨损为主,磨损率低;当磨粒的硬度超过涂层的硬度时,涂层的磨损以微切削为主,磨损率高。另外,WC-12Co涂层的耐磨性相对于16Mn钢也是随着磨粒的硬度变化而变化。 相似文献
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以钨钴氧化物、炭黑和VC为原料,采用原位还原碳化法制备WC-Co复合粉末,将复合粉末进行放电等离子烧结致密化制备WC-Co硬质合金块体材料。研究了不同VC添加量的复合粉末和块体材料的相组成、显微组织和性能,结果表明:VC的添加量对复合粉末的相组成、合金的晶粒尺寸和性能具有重要的影响,原料中添加2.0%VC(质量分数)时可获得平均晶粒尺寸为101 nm,相组成仅为WC和Co且具有高硬度和良好韧性的硬质合金块体材料。 相似文献
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采用低能等离子喷涂技术,在不锈钢基体上制备WC-12%Co涂层。粉末被气体送到喷嘴内、阴极与阳极之间的区域,喷涂功率为3.9~9.1kW。利用XRD和SEM分析技术,对涂层的微观结构和相组成进行分析,研究喷涂功率对涂层硬度的影响。结果表明:在功率3.9kW时制备的涂层主要由WC相组成;喷涂功率在5-9kW时,涂层中开始出现W2C;在功率6.5kW时,涂层硬度最高为1500HV,喷涂功率超过6.5kW时,由于涂层中出现α-W2C,涂层的硬度降低。这表明低能等离子炬可以制备高性能的WC-Co涂层。 相似文献
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SHI Xiaoliang SHAO Gangqin DUAN Xinglong YUAN Runzhang 《稀有金属(英文版)》2006,25(2):150-155
Nanocrystalline WC-Co composite powder and coated tungsten diamond by using vacuum vapor deposition were consolidated by the spark plasma sintering (SPS) process to prepare diamond-enhanced WC-Co cemented carbide composite materials. The interface microstructures between coated tungsten diamond and WC-Co cemented carbide matrix were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). The results showed that there is a transitional layer between the diamond and the matrix, in which the carbon content is 62.97wt.%, and the content of cobalt in the transitional zone is 6.19wt.%; the content of cobalt in the WC-Co cemented carbide matrix is 6.07wt.%, in which the carbon content is 15.95wt.%, and the content of cobalt on the surface of diamond is 7.30wt.%, in which the carbon content is 80.38wt.%. The transitional zone prevents the carbon atom of the diamond from spreading to the matrix, in which the carbon content does coincide with the theoretical value of the raw nanocomposite powders, and the carbon content forms a graded distribution among the matrix, transitional zone, and the surface of diamond; after the 1280℃ SPS consolidated process the diamond still maintains a very good crystal shape, the coated tungsten on the surface of the diamond improves thermal stability of the diamond and increases the bonding strength of the interface between the diamond and the matrix. 相似文献
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