Diffraction study on the atomic structure and phase separation of amorphous ceramics in the Si-(B)-C-N system. 2. Si-B-C-N ceramics

被引：58

作者：

Haug, J ^{[1
]}

Lamparter, P ^{[1
]}

Weinmann, M ^{[1
]}

Aldinger, F ^{[1
]}

机构：

[1] Max Planck Inst Met Res, D-70569 Stuttgart, Germany

来源：

CHEMISTRY OF MATERIALS | 2004年 / 16卷 / 01期

关键词：

D O I：

10.1021/cm031088t

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The atomic structure and phase separation of amorphous Si-B-C-N ceramic powder samples obtained by thermolysis of boron-modified polysilazanes were investigated using X-ray and neutron diffraction in the wide-angle and small-angle scattering regimes. The short-range order of the Si-B-C-N ceramics corresponds to that of Si-C-N ceramics consisting of two separated amorphous phases: an amorphous graphite-like phase and amorphous Si3+(1/4)xN4-xCx (x = 0-4). The evaluation of the total pair correlation functions revealed that the boron atoms are bonded to nitrogen with B-N bond lengths typical for h-BN. These units are incorporated in the graphite-like phase not statistically, but within regions of BN-rings which are less extended than the regions formed by C-rings. X-ray diffraction phase analysis and small-angle scattering showed that the addition of up to 10 at. % of boron to Si-C-N ceramics significantly influences the high-temperature behavior of the ceramics: coarsening of the separated amorphous phases, the crystallization of Si3N4 and its decomposition are retarded, and evolution of a nanocrystalline SiC phase is observed.

引用

页码：83 / 92

页数：10

共 67 条

[1] PREPARATION OF SILICON CARBONITRIDES FROM AN ORGANOSILICON POLYMER .2. THERMAL-BEHAVIOR AT HIGH-TEMPERATURES UNDER ARGON [J].