Article ID Journal Published Year Pages File Type
1465634 Ceramics International 2006 4 Pages PDF
Abstract

Nextel 720/aluminosilicate composites were prepared by low pressure chemical vapor infiltration (LPCVI) at 550 °C using AlCl3–SiCl4–CO2–H2 precursor system. The microstructure and mullitization of the aluminosilicate matrix were monitored by SEM, DTA and XRD. The matrix consisted of concentric muti-layers like the annual tree rings and contained some isolated alumina particles and pores. The phase composition of the matrix was composed of an amorphous silica, γ-Al2O3, Al–Si spinel, an amorphous monophasic mixture (in which Al3+ and Si4+ were mixed at the molecular level), and an amorphous diphasic mixture (in which Al3+ and Si4+ were mixed at a nanometer scale). The mullitization of the matrix included three stages. Complex mullitization process and inhomogeneous microstructure of the matrix suggested that AlCl3 and SiCl4 were not molecularly mixed.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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