Novel Silicon‐Boron‐Carbon‐Nitrogen Materials Thermally Stable up to 2200°C
Novel Silicon‐Boron‐Carbon‐Nitrogen Materials Thermally Stable up to 2200°C
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DOI：
10.1111/j.1151-2916.2001.tb00984.x
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发表时间：
2004-12
影响因子：
3.9
通讯作者：
Zhi-chang Wang;F. Aldinger;R. Riedel
中科院分区：
文献类型：
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作者：
Zhi-chang Wang;F. Aldinger;R. Riedel
利用聚有机硼硅氮烷 [B(C2H4Si(Ph)NH)3]n 的聚合物向陶瓷转化合成了三种新型 Si-C-B-N 陶瓷组合物，即 Si2.9B1.0C14N2.9、Si3.9B1.0C11N3.2 和 Si5.3B1.0C19N3.4， [B(C2H4Si(CH3)NH)2–(C2H4Si(CH3)N(SiH2Ph))]n 和 [B(C2H4Si(CH3)–N(SiH2Ph))3]n，其中 Ph 是苯基 (C6H5)，在 1050°C 氩气中进行。 Si-B-C-N 陶瓷在 1000°C 至 2200°C 的温度范围内表现出显着的成分和质量变化稳定性，包括在氩气中将样品在最终温度下等温退火 30 分钟。 Si5.3B1.0C19N3.4在2200℃时的质量损失率低至1.4wt%·h−1，Si2.9B1.0C14N2.9为1.7wt%·h−1，Si3.9B1.0C11N3.2为2.4wt%·h−1。测得的质量损失率与纯SiC材料相当。作为结晶相，β-Si3N4 和 β-SiC 只存在于在 2200°C、0.1 MPa 的氩气中退火的样品中。由于热力学原因，β-Si3N4 在特定的温度和气压下应该分解成元素硅和氮。然而，我们的材料中存在 β-Si3N4 表明碳和硼在动力学上稳定了 Si3N4 基组合物。
Three novel Si-C-B-N ceramic compositions, namely Si2.9B1.0C14N2.9, Si3.9B1.0C11N3.2 and Si5.3B1.0C19N3.4, were synthesized using the polymer-to-ceramic transformation of the polyorganoborosilazanes [B(C2H4Si(Ph)NH)3]n, [B(C2H4Si(CH3)NH)2–(C2H4Si(CH3)N(SiH2Ph))]n, and [B(C2H4Si(CH3)–N(SiH2Ph))3]n, where Ph is phenyl (C6H5), at 1050°C in argon. The Si-B-C-N ceramics exhibited significant stability with respect to composition and mass change in the temperature range between 1000° and 2200°C, including isothermal annealing of the samples at the final temperature for 30 min in argon. The mass loss rate at 2200°C was as low as 1.4 wt%·h−1 for Si5.3B1.0C19N3.4, 1.7 wt%·h−1 for Si2.9B1.0C14N2.9, and 2.4 wt%·h−1 for Si3.9B1.0C11N3.2. The measured amount of mass loss rate was comparable to that of pure SiC materials. As crystalline phases, β-Si3N4 and β-SiC were found exclusively in the samples annealed at 2200°C at 0.1 MPa in argon. For thermodynamic reasons, β-Si3N4 should have decomposed into the elements silicon and nitrogen at that particular temperature and gas pressure. However, the presence of β-Si3N4 in our materials indicated that carbon and boron kinetically stabilized the Si3N4-based composition.