(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要:
關(guān)鍵字: 碳氮化鈦；碳熱還原；晶須；氣−液−固機(jī)制
whiskers synthesized through carbothermal reduction process
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Ti(C, N) whiskers were fabricated through carbothermal reduction of TiO2 in nitrogen at different temperatures. The raw materials were TiO2, carbon black, NaCl and NiCl2, among which NaCl was added to form the chlorides of Ti and NiCl2 was used as catalyst for whisker growth. The phases of the synthesized samples and the corresponding phase-transformation behavior were analyzed by XRD, the micrographs of synthesized samples were characterized by scanning electron microscopy (SEM). Furthermore, the growth mechanism of Ti(C, N) whiskers was discussed. The results show that TiO2 directly reacts with carbon black and nitrogen to form TiN phase at 1 200℃. When the temperature is in the range of 1 250−1 400 ℃, NaCl is decomposed and functions as a halogenation reagent of TiO2 and NiCl2 acts as catalysts for the Ti(C, N) whisker formation. The whiskers obtained are 10−30 μm in length and about 1 μm in diameter. The phenomenon that whiskers with smooth surfaces are terminated by a droplet of catalyst indicates that the whiskers are grown by the “vapor-liquid-solid” mechanism.
Key words: Ti(C, N); carbothermal reduction process; whiskers; VLS mechanism
