摘要
原料粉末氧化问题是亚微米晶硬质合金生产中一个不可回避的难题,因为氧化料会在硬质合金制备过程中形成粗晶或孔洞,使合金性能降低。本文在亚微米晶WC-Co硬质合金中添加氧化料并在不同温度下烧结,采用SEM观察氧化料在烧结过程中的形貌变化特征。结果表明压坯中的氧化料在烧结后会形成明显的粗晶组织。氢气烧结条件下粗晶组织更加明显。对粗晶组织的形成机理进行探讨,认为粗晶组织的形成是气相反应的结果,中间经过产生脱碳相组织CoxWyCx和W2C的过程。TG-DSC结果表明,在常压Ar气氛条件下,碳粉还原Co3O4的反应温度为732℃,碳粉还原WO3的反应温度为1 050℃。
Raw material oxidation is the most strict problem in submicron grain（≤0.8 μm） cemented carbides production.By means of adding oxide,the morphology of pores induced by the oxide in samples prepared at different sintering temperature was investigated using SEM.The results show that pores induced by oxide have obvious characterization of coarse grain structure.In addition,the mechanism of the coarse grain structure formation is discussed and it is recognized that the coarse grain structure is resulted from gas participated reaction.TG-DSC result shows the temperatures of carbon reducing Co3O4 and WO3 are around 732 ℃ and 1 050 ℃,respectively.
出处
《粉末冶金材料科学与工程》
EI
2010年第6期620-624,共5页
Materials Science and Engineering of Powder Metallurgy
基金
国家科技重大专项(20092X04012-032)
关键词
亚微米晶硬质合金
氧化料
孔洞
粗晶
气相反应
submicron grain cemented carbide
oxide
pore
coarse grain structure
gas participated reaction
