摘要
以甲基氢二氯硅烷、三氯化硼、六甲基二硅氮烷为起始原料,采用共缩合原理合成了聚硼硅氮烷(PBSZ)先驱体,将PBSZ分别在N_2和NH_3/N_2气氛中高温热解得到SiBNC陶瓷.利用元素分析、XPS、NMR、FT-IR、XRD等分析手段对PBSZ及其陶瓷产物的组成、结构和热稳定性进行了表征.结果表明,先驱体的结构骨架为-Si-N-B-,其中B、N以硼氮六环的形式存在,C以Si-CH_3形式存在.1000℃时两种气氛中陶瓷产率分别为63wt%和61wt%,1500～1850℃之间失重分别为3.8wt%和10.0wt%.所得陶瓷的主要相组成均为Si_3N_4、BN和SiC,并且均能在1700℃以上保持非晶,在1850℃时部分结晶.N_2中热解产物比NH_3/N_2中热解产物有更好的稳定性,更不易结晶.
Polyborosilazane （PBSZ）, a precursor to SiBNC ceramic, was synthesized via cocondensation approach using methyldichlorosilane （MeHSiCl2）, boron trichloride （B Cl3） and hexamethydisilazane （HMDZ） as starting materials. SiBNC ceramics were obtained by pyrolysing the as-synthesized PBSZ in N2 or NH3/N2 atmospheres. The chemical composition, structure and high temperature properties of the polymer and ceramics were investigated by using EA, XPS, FTIR, NMR, and XRD. The results indicate that the backbone of PBSZ is -Si-N-B- linkage in the form of borazine and C is in the form of Si-CH3. The ceramic yield of the PBSZ pyrolysed at 1000℃ in N2 and NH3/N2 atmospheres is 63wt% and 61wt%, respectively. The products show excellent high temperature stability which are fully amorphous to 1700℃. Furthermore, only partial crystallization, giving a mixture of Si3N4, BN and SiC phases, is observed heating at 1850℃. The weight loss of SiBNC ceramics pyrolyzed in NH3/N2 and N2 atmospheres from 1500℃ to 1850℃ is about 10.0wt% and 3.8wt%, respectively. The N2 pyrolyzed products show better stability than the NH3/N2 pyrolyzed products and have less tendency to crystalline at higher temperature.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2008年第3期525-530,共6页
Journal of Inorganic Materials
基金
国防基础科研项目(A2820060068)
关键词
SiBNC陶瓷
先驱体转化法
聚硼硅氮烷
耐高温
SiBNC ceramics
polymer prolysis
polyborosilazane
high temperature resistance
