理論分析
(1. 武漢理工大學(xué) 理學(xué)院，武漢 430070;
2. 武漢理工大學(xué) 材料復(fù)合新技術(shù)國(guó)家重點(diǎn)實(shí)驗(yàn)室，武漢 430070)
摘 要: 以Ti粉、Al粉、活性炭和Si粉為原料，采用放電等離子工藝分別以摩爾比為2.0Ti/1.1Al/1.0C、2.0Ti/1.0Al/0.1Si/1.0C、2.0Ti/1.0Al/0.2Si/1.0C、2.0Ti/0.9Al/0.2Si/1.0C和2.0Ti/1.0Al/0.3Si/1.0C，在1 200 ℃合成了Ti2AlC/Ti3AlC2塊體材料。通過(guò)合成試樣的X射線衍射譜，確定了放電等離子合成試樣的物相組成，并用掃描電鏡結(jié)合能譜儀觀察了合成試樣的顯微結(jié)構(gòu)和微區(qū)成分。結(jié)果表明：以2.0Ti/1.1Al/1.0C為原料放電等離子合成了層狀結(jié)構(gòu)明顯的Ti2AlC材料；摻Si后所有試樣都由Ti2AlC、Ti3AlC2和Ti3SiC2 3種物相組成；當(dāng)摻Si量逐漸增大，即Al與Si的量比減小時(shí)，試樣中Ti3AlC2和Ti3SiC2的含量增加，而Ti2AlC的含量降低，同時(shí)顆粒得到細(xì)化。應(yīng)用量子化學(xué)計(jì)算結(jié)果解釋了摻Si后不利于Ti2AlC的生成，而有利于Ti3AlC2的生成機(jī)理，說(shuō)明了摻Si后固溶體的產(chǎn)生過(guò)程。
關(guān)鍵字: 硅摻雜；放電等離子燒結(jié)；Ti2AlC/Ti3AlC2；理論分析
doping by spark plasmasintering and
theoretical analysis
（1. School of Science, Wuhan University of Technology,Wuhan 430070, China;
2. State Key Laboratory of Advanced Technology forMaterials Synthesis and Processing,Wuhan University of Technology,
Wuhan 430070, China）
Abstract:Ti2AlC/Ti3AlC2 bulk material was synthesized by spark plasma sintering (SPS) at 1 200 ℃ using elemental powder mixture of Ti, Al, active carbon and Si whose molar ratios were 2.0Ti/1.1Al/1.0C, 2.0Ti/1.0Al/0.1Si/1.0C, 2.0Ti/1.0Al/0.2Si/1.0C, 2.0Ti/0.9Al/0.2Si/1.0C and 2.0Ti/1.0Al/0.3Si/1.0C. X-ray diffractometry was used to determine the phase composition, and scanning electron microscopy with energy-dispersive spectroscopy was observed to investigate the microstructure of samples and components in selected area respectively. The results show that Ti2AlC bulk material which has obvious layered structure can be synthesized by SPS from 2.0Ti/1.1Al/1.0C at 1 200 ℃. On the other hand, the samples Si doping are made of Ti2AlC, Ti3AlC2 and Ti3SiC2. When the amount of Si doping increases and molar ratio of Al to Si decreases, the amount of Ti3AlC2 and Ti3SiC2 increases while Ti2AlC decreases. At the same time, the size of layered crystal grain becomes refined. The mechanism that Si doping is not helpful to form Ti2AlC is explained according to the results of quantum chemistry calculation. The formation of Si solid solution after Si doping is illuminated.
Key words: Si doping; spark plasma sintering; Ti2AlC/Ti3AlC2; theoretical analysis
