纳米W、C调碳剂对WC-Co合金烧结过程中液相出现温度的影响

烧结过程中粉体压坯的物理冶金与化学变化规律是粉末冶金材料烧结工艺制订的基础。本文采用差示扫描量热法(DSC)与热重法(TG)研究了纯氩气气氛下室温～1400℃之间纳米W、纳米C调碳剂对WC-11%Co混合料烧结过程中液相出现温度的影响。结果表明,由于纳米W或C的加入,WC-Co合金液相出现最低温度可降低至1226.5℃～1228.6℃,同时出现液相的分步形成现象。对正常含碳型混合料,烧结过程中液相集中出现温度为1374.8℃。由于纳米W或纳米C的加入,缺碳型混合料与过剩碳型混合料烧结过程中液相集中出现温度分别为1346.2℃与1343.3℃,分别降低了28.6℃与31.5℃。

Effect of Carbon-adjusting Elements of Nano Tungsten and Nano Carbon on Liquid Phase Emerging Temperature of WC-Co Alloy during Sintering Process

The variations of physical metallurgy and chemistry during sintering process are important basis for the determination of the sintering technique of powder metallurgy material. Differential scanning calorimetry （DSC） and thermal gravimetry （TG） were used in studying effect of the carbon-adjusting dements of nano tungsten and nano carbon on the liquid phase emerging temperature of WC-11Co alloy from room temperature to 1 400 ℃ in argon atmosphere. It is shown that the addition of nano tungsten or nano carbon can result in the emerging of liquid phase at 1 226.5 ℃ to 1 228.6 ℃, accompanied by the phenomenon of multistep formation of liquid phase. For the WC--Co mixed powder with normal carbon content, the mass liquid phase emerging temperature is 1 374.8℃. Nevertheless, because of the addition of nano tungsten or nano carbon, the mass liquid phase emerging temperatures for carbon deficient and carbon residue types of WC-Co mixed powders are reduced to 1 346.2℃ and 1 343.3 ℃, respectively, 28.6 ℃ and 31.5 ℃ lower than the one Of normal carbon type, respectively.