液态聚硼硅氮烷的陶瓷化过程

采用Fourier红外光谱、热重–差热以及X射线衍射分析对新型液态SiBNC先驱体进行了结构表征,重点研究了先驱体的陶瓷化过程。结果表明：先驱体以—CH3和—CH=CH2为侧链基团,含有C—H、C=C、Si—H、B—N、N—H、Si—N等化学键;N2气氛保护下的陶瓷产率约为85%,质量损失主要发生在300～800℃;随着温度的升高,聚合物中有机基团逐渐减少,900℃完成无机化转变,得到含有自由碳的非晶态SiBNC陶瓷,1200℃以上非晶态SiBNC陶瓷开始晶化,1500℃得到由C、SiC、Si3N4和BN组成的复相陶瓷。

Polymer-Ceramic Conversion of Liquid Polyborosilazanes

The chemical structure and ceramization process of a liquid polymer precursor for SiBNC ceramics were investigated by Fourier transform infrared spectrometry,thermal gravimetric–differential scanning calormetry analysis and X-ray diffraction,respec-tively.The results indicate that there are the side substituents of —CH3 and —CH=CH2,and the bonds of C—H,C=C,Si—H,B—N,N—H,Si—N in the precursor structure.The ceramic yield of the precursor obtained in nitrogen atmosphere is 85%(in mass) and the mass loss occurs mainly in 300–800 ℃.The amounts of organic groups decrease with the increase of temperature.The amorphous SiBNC ceramics containing free carbon were obtained at 900 ℃.The ceramics started to crystallize above 1 200 ℃,resulting in the formation of partially crystallized phases of C,SiC,Si3N4 and BN.