(中南工業(yè)大學(xué) 粉末冶金研究所，長(zhǎng)沙 410083)
摘 要: 研究了在中位徑為0.42 μm的碳化硼微粉中添加1%～4%碳為活化劑的燒結(jié)過程。研究了燒結(jié)坯的密度、抗彎強(qiáng)度、晶粒度與摻碳量、燒結(jié)溫度、保溫時(shí)間的關(guān)系。在一定燒結(jié)溫度以上，少量碳的摻入明顯提高了燒結(jié)活性，燒結(jié)坯密度明顯提高，在本實(shí)驗(yàn)條件下，最佳摻碳量為1%～2%，最佳燒結(jié)溫度為2 160～2200℃。研究了摻碳碳化硼燒結(jié)動(dòng)力學(xué)，得出其物質(zhì)遷移機(jī)制主要為晶界擴(kuò)散。最后研究了其相組成，摻入的碳除溶解于碳化硼外，以游離碳形式存在，沒有新相生成。
關(guān)鍵字: 碳化硼；活化燒結(jié)；燒結(jié)動(dòng)力學(xué)
（Research Institute for Powder Metallurgy, Central South University of Technology, Changsha 410083, P. R.China）
Abstract:The activated sintering processes of boron carbide with 1%～4% carbon as activator were studied. The mean size of boron carbide ultrafine powder was 0.42μm. The relationships between the density, bending strength and grain size of the sintered compact and the quantity of additives, sintering temperature, sintering time were investigated . It was showed that the density of the sintered compact increased even with the addition of little amount of additive(carbon). The optimum amount of the additive (carbon) is 1%～2%, and the optimum sintering temperature is 2 160～2 200 ℃. The activated sintering kinetics of boron carbide with carbon as activator were also researched, the results showed that the main transport mechanism was grain boundary diffusion. Finally, the constitution of carbon phase was studied, it was showed that the form of the added carbon after sintering was free carbon besides those dissolved in boron carbide, and no new phase was formed.
Key words: boron carbide; activated sintering; sintering kinetics
