SiC质耐火材料的碳化氮化制备及性能

Preparation and Properties of SiC Refractories via Carbonization-Nitridation Reaction

以Si粉和SiC颗粒为原料,采用碳化-氮化反应在1 400℃和1 500℃制备了SiC质耐火材料。采用X射线衍射仪、扫描电子显微镜和能谱仪等对试样的物相组成、显微结构和微区成分进行了分析,研究了原料组成和烧成温度对材料烧结性能、力学性能和抗热震性能的影响,并对原料组成和烧成温度进行了优化。结果表明:所制备的SiC质耐火材料的主要物相组成为α-SiC、β-SiC和Si2N2O;随着Si粉加入量的增加,试样的体积密度和抗折强度先增加后降低。1 400℃制备的试样的体积密度和抗折强度高于1 500℃制备的试样的;Si粉添加量为25%(质量分数),烧成温度为1 400℃时试样的性能最优,其体积密度为2.45 g/cm3,抗折强度为96.85 MPa,1 200℃热震一次后残余抗折强度达68.78 MPa。

The SiC refractories were prepared using Si and SiC powders as raw materials via carbonization–nitridation reaction at 1 400 ℃ and 1 500 ℃,respectively.The phase composition,microstructure and micro-area element were analyzed by X-ray diffrac-tion,scanning electron microscope and energy dispersive spectroscopy.The effect of raw materials composition and preparation tem-peratures on the sintering properties,mechanical properties and thermal shock resistance of the refractories were investigated.The raw materials composition and preparation temperature were optimized.The results show that the main phases of the samples are α-SiC,β-SiC and Si2N2O.With the increase of Si powder addition,both the bulk density and flexural strength of the samples increase firstly and then decrease.The bulk density and flexural strength of the samples prepared at 1 400 ℃ are higher than that at 1 500 ℃.The samples fabricated at 1 400 ℃ with 25%（in mass） Si have better properties with density of 2.45 g/cm3,flexural strength of 96.85 MPa,and residual flexural strength of 68.78 MPa after one time thermal shock resistance test at 1 200 ℃.