排序方式: 共有13条查询结果,搜索用时 15 毫秒
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干混合对硬质合金组织结构的影响 总被引:2,自引:2,他引:2
采用扫描电镜,通过对WC原料粉末、脱蜡压坯断口与表面、合金抗弯强度样品断口与合金烧结体表面微观形貌以及合金金相组织的观察,研究了干混合对硬质合金组织结构的影响。结果表明,干混合只对压坯成形过程中粉末颗粒的压制行为与烧结过程中合金的致密化行为产生影响,不会对烧结过程中的合金化行为产生影响。压坯中的大孔洞与未压好等压制缺陷以及显著的元素分布不均匀现象难以通过液相烧结得到有效消除,会继续保留至合金中。采用干混合工艺制备合金,合金晶粒均匀、粗大,接近原料粉末的电镜观测粒度。 相似文献
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WC粉末粒度与形貌对硬质合金中WC晶粒度、晶粒形貌与合金性能的影响 总被引:5,自引:0,他引:5
探讨了粗颗粒与特粗颗粒两种粒度级别以及平面化表面与球化表面两种形貌特征的WC原料对WC-Co硬质合金中WC晶粒度、晶粒形貌以及合金性能的影响。结果表明,分别采用费氏粒度为11.4 ̄13.4μm,与22.0 ̄28.3μm两种粒度级别的WC粉末为原料制备合金,尽管两种合金硬度之间存在明显差别,但是两种合金的晶粒度相差很小,在4.0 ̄4.3μm之间,同属一种粒度级别。WC原料的原始形貌对合金中WC晶粒形貌与合金性能影响很小,碱金属掺杂原料制备的合金中WC晶粒结晶完整性相对较差。因此,高纯原料是制备高性能硬质合金的基础。 相似文献
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A fine and platelet tungsten carbide patterned structure with fine yttrium containing dispersed phase was observed in liquid phase sintered WC-20% Co-1%Y2O3 cemented carbide with ultrafine tungsten carbide and nano yttrium oxide as starting materials. By comparing the microstructures of the alloy prepared by hot-press at the temperature below the eutectic melting temperature and by conventional liquid phase sintering, it is shown that hexagonal and truncated trigonal plate-like WC grains are formed through the mechanism of dissolution-precipitation (recrystallization) at the stage of liquid phase sintering. Yttrium in the addition form of oxide exhibits good ability in inhibiting the discontinuous or inhomogeneous WC grain growth in the alloy at the stage of solid phase sintering. 相似文献
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Co掺杂对粗颗粒、特粗颗粒WC粉末粒度与微观形貌的影响 总被引:1,自引:0,他引:1
以粗颗粒与特粗颗粒W粉为原料,研究了Co掺杂对粗颗粒与特粗颗粒WC粉末粒度与微观形貌的影响。结果表明,Co掺杂有利于WC粉末Fsss的提高与游离碳的降低,有利于得到单晶WC粉末。当Co掺杂量为w(Co)=0.035%时,WC粉末颗粒与晶粒形貌发生巨大变化,WC晶粒的结晶完整性明显改善,呈现明显的生长台阶与生长平面,但特粗颗粒WC粉末颗粒形貌的规则度较粗颗粒WC粉末的低。当碳化温度由1900℃提高到2000℃后,Co掺杂特粗WC颗粒表面出现大量WC纳米颗粒依附物。 相似文献
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以Co(At)2·4H2O为原料,采用高压水热合成法,于氧分压4 MPa、200℃下水热反应20 h制备纳米氧化钻粉末.采用比表面积分析仪、X射线衍射仪(XRD)、透射电镜(TEM)等对产物进行分析和表征.结果表明,产物为单一相成分的立方相尖晶石结构Co3O4,比表面积平均粒径为52.7 nm,具有球形形貌特征.Co3O4的高压水热合成机理是钴离子水解产物中部分Co2+的羟基配合物被氧化成Co2+的羟基配合物,形成[Co(OH)4]2-与[Co(OH)6]3-配位多面体生长基元,随后生长基元通过缩聚反应形成近程有序的Co3O4原子团.Ac-的表面吸附有效地阻碍了Co3O4的各向异性生长与连续晶粒长大. 相似文献
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随着电力系统发展,其主要电气控制设备断路器的功率不断提升。作为断路器的核心部件,电触头材料的研究得到了越来越广泛的关注。本文以铜粉、铬粉和石墨烯为原料,分别通过机械混合法和化学气相沉积法添加石墨烯,再通过压制-烧结-复压-复烧工艺制成石墨烯增强铜铬复合材料。研究了不同工艺添加石墨烯对铜铬复合材料组织及性能的影响。研究发现,通过化学气相沉积法添加的石墨烯在基体中分布均匀,电导率提升至40.64 MS/s、平均燃弧时间为5.37 ms、熔焊力变化范围为13.550~13.636 N,电导率、抗熔焊性能和耐烧蚀性能等得到了明显的提高,有利于其进一步扩大在电接触材料领域的应用范围。 相似文献
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Three observation methods were used to investigate the existing form and the behavior of rare earth during the sintering process of high activity mischmetal (RE, with lanthanum and cerium) doped WC-8%Co-0.048%RE(mass fraction) alloy with low carbon-containing level by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS), considering the fact that the addition amount of rare earth in the alloy is very minute. The directional migration process and mechanism of cerium were discussed. First, the sinter skin (surface) is observed. oxide on the sinter skin, and lanthanum in these cerium observed, and lanthanum containing phase/micro-zone in It is shown that there exists a dispersedly distributed cerium containing enrichment positions is very minute. Secondly, the polished section is the alloy is identified. Finally, based on the fact that the fracture of cemented carbide is resulted from the heterogeneous phase or other defects within the microstructure, the fracture surface is observed and cerium containing phase/micro-zone in the fracture source approximately 260 μm from the surface is identified. These combined observations reveal adequately the fact that lanthanum and cerium get separated and cerium predominantly migrates towards the surface during the sintering process. 相似文献