A series of polyaluminocarbosilane (PACS) as precursors for SiC(Al) ceramics were prepared from polysilacarbosilane (PSCS) and aluminum acetylacetonate [Al(AcAc)3] by various ratios. The PACS containing various amount of aluminum were characterized by chemical analysis, gel permeation chromatograms (GPC) and FTIR. And effects of aluminum content on the structure and properties of PACS were investigated. With increasing aluminum content, PACS would have higher oxygen content, broader molecular weight distribution, lower Si—H content and worse spinnability. When Al(AcAc)3/PSCS was more than 20%, PACS could not be melting spun. Moreover, when PACS was prepared by Al(AcAc)3/PSCS＞4 wt%, the weight loss in N2 from 400 to 560 ℃ decreased. The Si-Al-C-O fibers derived from PACS with 0.4 wt%～0.7 wt% aluminum content show high tensile strength. The SiC(Al) fiber derived from PACS obtained from Al(AcAc)3/PSCS＝6 wt% was the best sintered.

Key words: polyaluminocarbosilane, aluminum content, ceramic yield, silicon carbide