Effect of the addition of acetic acid on spinning sol and mullite fibers properties

Abstract

The preparation of mullite fibers by sol-gel method is the preferred method in industrial production, where the stability, rheological properties and microstructure of spinning sols are essential for the preparation of continuous, low-defect fibers. In this study, aluminum carboxylate solutions (ACs) were prepared using aluminum powder, formic acid and acetic acid as raw materials, silica sol was added, and spinnable sol was obtained by concentration and aging. After dry spinning and calcination at 1200 °C, continuous mullite fibers with mullite as the main crystal phases were obtained. The effect of acetic acid addition on the stability of Al-Si mixed sol was studied, and the polymerization process of spinning sol was studied on its rheological properties and microstructure. The cross-section of mullite fibers obtained after calcination at 1200 °C was “dumbbell” type, and the cause of this cross-section was discussed, which laid a foundation for subsequent optimization research.