Synthesis of a Novel Polyaluminocarbosilane Precursor With Excellent Spinnability for High‐Performance SiC Fibers by a One‐Step Catalytic Reaction Method

ABSTRACT As high‐performance enhancement materials of advanced ceramic composites, continuous silicon carbide (SiC) fibers have become indispensable in the fields of aviation, aerospace, and nuclear power. Polyaluminocarbosilane (PACS) precursor is a key raw material for high‐performance continuous SiC fibers. However, the PACS precursors are usually prepared by a two‐step complex reaction of silicon compounds and aluminum compounds under high temperatures (>450°C). In this work, a novel PACS precursor was successfully synthesized by a one‐step catalytic reaction method at low temperature (<350°C) based on a synergistic Lewis acid and Bronsted acid catalytic mechanism. The composition and structure of PACS were successfully controlled by adjusting the ratios of the raw materials. The PACS precursor with high ceramic yield (73.10% at 1000°C), excellent spinnability and adjustable aluminum content (0.06–0.47 wt%) was obtained. The high‐performance SiC fibers with a fine diameter (7.71±0.24 µm) and high tensile strength (1.90±0.40 GPa) were obtained from the PACS‐8 precursor via melt spinning, air curing, and pyrolysis at 1800°C. The proposed synthetic route enables novel PACS precursors and shows potential for the production of high‐performance continuous SiC fibers and related ceramic materials.