(西安建筑科技大學(xué) 材料與礦資學(xué)院，西安 710055)
摘 要: 在XRD、SEM、能譜分析、TEM、TG-DSC等實(shí)驗(yàn)分析的基礎(chǔ)上，對(duì)以TiO2、B2O3、C為原料，通過碳熱還原法合成TiB2粉末的反應(yīng)傳質(zhì)機(jī)理進(jìn)行了研究，闡明碳熱還原法合成TiB2的反應(yīng)傳質(zhì)機(jī)理，建立碳熱還原法合成TiB2的反應(yīng)傳質(zhì)模型。研究表明：在碳熱還原TiO2的過程中，由低溫到高溫，最穩(wěn)定的還原產(chǎn)物分別是Ti4O7和Ti3O5，尤其當(dāng)溫度超過1300℃以后，Ti3O5為最穩(wěn)定的還原產(chǎn)物。在碳熱還原TiO2與B2O3合成TiB2的反應(yīng)過程中，DDSC曲線上有幾個(gè)明顯的吸熱峰，這分別對(duì)應(yīng)于TiO2→Ti4O7→Ti3O5→TiB2的反應(yīng)階段。碳與氧化物顆粒之間是通過CO/CO2氣體偶實(shí)現(xiàn)質(zhì)量傳遞的。在反應(yīng)體系中，B2O2(g)氣相、Ti3O5(s)固相分別是形成TiB2的前驅(qū)體。
關(guān)鍵字: TiB2；碳熱還原；傳質(zhì)機(jī)理；傳質(zhì)模型
（College of Materials and Mineral Resources, Xi’an University of Architecture and Technology, Xi’an 710055, China）
Abstract:On the basis of experiment analysis such as XRD, SEM, energy spectrum analysis, TEM and TG-DSC, the reactionary mass transfer mechanism of synthesizing TiB2 by carbothermal reducing TiO2 and B2O3 was studied. The reactionary mass transfer mechanism of synthesizing TiB2 by carbothermal reduction method was analyzed, and the reactionary mass transfer model of synthesizing TiB2 by carbothermal reduction method was built. The results show that, during carbothermal reduction of TiO2, the most stable reduction products are Ti4O7 and Ti3O5 from low temperature to high temperature, respectively, when the reduction temperature is over 1 300 ℃, Ti3O5 is the most stable reduction product.There are several endothermic peaks on DDSC curve in the process of synthesizing TiB2 by carbothermal reducing TiO2 and B2O3, which correspond to reaction stage of TiO2→Ti4O7→Ti3O5→TiB2, respectively. The mass transfer from carbon to the oxide particle is realized by the CO/CO2 gas couple. In reactionary system, B2O2(g) and Ti3O5(s) are the precursors of formation TiB2 by carbothermal reduction.
Key words: TiB2; carbothermal reduction; mass transfer mechanism; mass transfer model
