摘要
采用球磨破碎分级的氧化钨为原料,氢还原制备出平均粒度为30 nm的纳米钨粉,并分别以干磨搅拌和添加适量分散剂的湿式球磨的方式配碳,然后置于通氢钼丝碳化炉中在1180℃长时间碳化,得到了粒度分别为109和148 nm的碳化钨粉末,继而于低压真空烧结炉中,在1360℃的温度下烧结制备出WC-7%Co(质量分数)烧结体,研究了纳米钨粉形貌结构对纳米碳化钨粉末及其超细晶硬质合金性能的影响。通过比表面测定仪和费氏粒度仪测定了粉体的比表面和粒度,采用X射线衍射(XRD)分析了碳化产物的相成分,用扫描电镜(SEM)观察了粉末的形貌和烧结体的显微组织结构,按硬质合金性能测试标准对WC-Co烧结体的物理和力学性能进行了测定。结果表明,湿磨配碳强制破坏了纳米钨颗粒,呈其氧化钨前驱体的团聚状的形貌结构,可以改善纳米钨粉和碳粉弥散分布的均匀性,更有利于获得颗粒细小、均匀,分散性好的优质纳米碳化钨粉,其所制备的超细晶WC-7%Co硬质合金,显微组织均匀,综合性能优,硬度和抗弯强度分别为HRA 93.7和4450 MPa。
Tungsten carbide powders with the mean particle size of 109 and 148 nm were prepared at 1180 ℃ in hydrogen molybdenum carbonization furnace by carbonizing the mixture powders of tungsten and carbon black mixed by wet ball milling and dry mixer milling respectively. WC-7% Co （mass fraction） alloys were sintered at 1360 ℃ in the low-pressure vacuum sintering furnace. The effects of morphology of tungsten nano-powders on the properties of tungsten carbide powders and ultrafine cemented carbides were stud- ied. Tungsten nano-powders with the mean particle size of 30 nm were prepared through hydrogen reduction process using ball milling tungsten oxide powder as raw material. The particle size and specific surface of powders were measured by Fisher sizer and specific surface equipment, the phases of carbonization products were analyzed using X-ray diffraction （XRD） and the morphologies and microstructures of powders and sintered alloys were observed by scanning electronic microscope （SEM）. The physical and mechanical properties of WC-TCo sintered composites were tested according to related material performance testing standard. It showed that the aggrega- tion of tungsten nano-powders was dispersed by wet ball milling and the distribution of mixtures of tungsten powders and carbon black were improved. High quality tungsten carbide nano-powders were prepared through wet ball milling. The microstructures of ultrafine WC-TCo sintered composites prepared from the powders through wet ball milling method were homogenously and the properties of the alloy were excellent, the hardness and bending strength were HRA 93.7 and 4450 MPa, respectively.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2014年第1期48-54,共7页
Chinese Journal of Rare Metals
基金
国家自然科学基金(50801037
51071082
51271090)
国家教育部博士学科点专项基金(20103601110001)
国家教育部长江学者和创新团队发展计划(IRT0730)
国家教育部新世纪优秀人才支持计划(NECT-10-0184)
江西省高等学校科技落地计划(12056)资助项目
关键词
形貌结构
粉末冶金
纳米碳化钨粉
配碳方式
morphology structure
powder metallurgy
tungsten carbide nano-powders
carbon mixture means
