TiB_2/SiC陶瓷复合材料制备工艺的研究

以TiO2、B4C和C为原料,基于原位合成法在SiC基体中生成TiB2颗粒,并采用无压烧结法制备出TiB2/SiC复合陶瓷.通过对复合材料制备工艺的研究,发现：高于1 300℃的预烧结能形成TiB2/SiC复合陶瓷坯体.C含量、烧结温度和保温时间对复合材料的相对密度均有影响.当C含量（质量分数）为4%时、在1 400℃×60 min＋2000℃×30 min的烧结工艺下能够制备出致密的TiB2/SiC陶瓷复合材料.微米级TiO2粉比纳米级TiO2粉更有利于形成较致密的烧结复合材料.随着生成TiB2体积分数的增加（5%～20%）,复合材料中TiB2颗粒逐渐粗化,间距逐渐变小.对复合材料的烧结机理还进行了分析.

Study on synthetic conditions of TiB_2/SiC ceramic composite

A with pressureless sintering technique the TiB2 reinforced SiC-ceramic composites were synthe sized by using TiO2,B4C,C and SiC as starting materials.the sintering mechanism of TiB2/SiC ceramic composites was discussed.Detailed studies of the synthetic parameters reveal that： firstly,pre-sintering at over 1 300 ℃ initiates the formation of TiB2.Secondly,carbon contents,sintering temperatures and time all have influence on the relative densities of sintered TiB2/SiC ceramic composites.Thirdly,the densified TiB2/SiC ceramic composites can be obtained under conditions that carbon content of 4 wt.%,pre-sintering temperature at 1 400 ℃ for 60 min and sintering temperature at 2 000 ℃ for 30 min.Finally,compared with the nano-sized TiO2 powders,the micron-sized TiO2 powders are benlicial to form sintered composites with higher relative densities.Additionally,TiB2 particles tend to coarsen the sizes with the increase in the volume percentages of TiB2 ranging from 5% to 20%.