(1.中南大學(xué) 材料科學(xué)與工程學(xué)院, 長(zhǎng)沙 410083；
2. Department of Chemical Engineering, University of Sherbrooke,
Sherbrooke, J1K 2R1, Canada)
摘 要: 用射頻感應(yīng)等離子體將鎢粉炭化成碳化鎢, 對(duì)炭化過后的粉末在氬氣保護(hù)下, 于1900℃進(jìn)行燒結(jié)處理, 并對(duì)在感應(yīng)等離子體中鎢粉被甲烷炭化的反應(yīng)過程和在高溫基體上碳與沉積物進(jìn)一步反應(yīng)的機(jī)理進(jìn)行了研究。采用掃描電鏡和X射線衍射儀分析了原始鎢粉、炭化粉末和反應(yīng)沉積物的顯微組織和成分。 結(jié)果表明， 快速炭化反應(yīng)開始于金屬鎢粉熔化后, 顆粒尺寸為5μm的鎢粉在等離子體中被部分炭化, 完全炭化要靠反應(yīng)沉積物在高溫基體上與碳的進(jìn)一步反應(yīng)來實(shí)現(xiàn), 經(jīng)炭化的鎢粉在熱處理時(shí)存在脫碳現(xiàn)象。
關(guān)鍵字: 鎢粉；甲烷； 感應(yīng)等離子體； 碳化鎢； 炭化過程
deposited in radio frequency induction plasma
（1. School of Materials Science and Engineering,
Central South University, Changsha 410083, China；
2. Department of Chemical Engineering,
University of Sherbrooke, Sherbrooke, J1K 2R1, Canada）
Abstract:Radio frequency induction plasma was used to synthesize tungsten carbide directly from metallic tungsten powder. The carburization process of tungsten particles with methane in the induction plasma and the reaction between carbon and deposit on the high temperature substrate were investigated. Carburized tungsten powder was sintered at 1900℃ under the protection of Ar. Scanning electron microscopy and X-ray diffraction were used to analyze the starting tungsten powder, the carburized tungsten powder and the deposit. The results show that rapid carburization of the tungsten powder in the reactive plasma starts when tungsten particles are melted. Within the plasma flame, the tungsten powder with 5μm can only be partially carburized. Completion of the carburization process requires the reaction between involved carbon and the deposit on the substrate at high temperatures. Decarburization phenomenon happens during the heat treatment of the carburized powder.
Key words: tungsten powder； methane； induction plasma； tungsten carbide； carburization process
