用叶蜡石与金红石碳热还原–氮化合成Sialon–Ti(N,C)复合材料

Synthesis of Sialon–Ti(N,C) Composites via Carbothermal Reduction–Nitridation from Pyrophyllite and Rutile

以叶蜡石、金红石和焦炭粉为原料,通过碳热还原–氮化反应合成sialon–Ti(N,C)复合材料。利用X射线衍射仪、扫描电子显微镜和能谱仪对产物的物相组成、显微结构和微区成分进行了分析,研究了合成温度和配炭量对产物物相组成和显微形貌的影响。结果表明:当叶蜡石与金红石质量比为4:1、配炭量过量50%、合成温度为1 500℃时,合成的sialon–Ti(N,C)复合材料中TiN0.7C0.3晶粒尺寸约为200nm,产物为β-sialon、15R-sialon、TiN0.7C0.3、刚玉和少量β-SiC;当配炭量过量50%,合成温度从1400℃升高到1550℃,产物中β-sialon和TiN0.7C0.3含量逐渐增加。相同合成温度下,配炭量对产物物相组成有重要影响,配炭量过量50%有利于sialon–Ti(N,C)复合材料的合成;当配炭量较少时,产物中出现O’-sialon和Si2N2O;当配炭量过多时,β-sialon向15R-sialon转变。

Sialon-Ti（N,C） composites were synthesized using pyrophyllite, rutile and coke powers as raw materials via carbothermal reduction-nitridation reaction. Phase composition, microstructure and micro-area element of the synthesized resultant were analyzed by X-ray diffractometer, scanning electron microscope and energy dispersive spectrometer. The effects of synthesis temperature and carbon addition content on phase compositions and mierostructure of the resultants were investigated. The results showed that the main phases of the samples which were composed of pyrophyllite and rutile with a mass ratio of 4：1, with addition of 50% excessive carbon, synthesized at 1 500 ℃ were β-sialon, 15R-sialon, TiN0.7C0.3, corundum, and a little β-SIC. Content of β-sialon and TiN0.7C0.3 increased with the increase of the synthesis temperature from 1 400 ℃ to 1 550 ℃. The content of carbon addition had an important influence on phase composition when the samples were synthesized at same temperature. It was beneficial for synthesizing sialon-TiCN,C） composite material when 50% excessive carbon was added in the samples. O＇-sialon and Si2N20 will appear in resultants while the addition of carbon content was small, but β-sialon will transform to 15R-sialon while too much carbon added in the samples.The grain size of TiN0.TC0.3 crystal in sialon-Ti（N,C） composites was about 200 nm when 50% excessive carbon added in sample and synthesized at 1 500 ℃.