Online preparation of high-quality BN coatings with atomic diffusion based on carbon-free water-soluble precursor

Efficient and environmentally friendly production of high-quality continuous fiber coatings using current preparation methods is highly challenging due to issues such as scale and batch processing restrictions, low deposition rate, high energy consumption, and the utilization of multiple environmentally hazardous steps. To address these challenges, we propose a stable and efficient wet chemical deposition coating method for the high-throughput online continuous preparation of BN coatings on ceramic fibers under ambient environment. Our process involves surface modification, in-situ wet chemical deposition, and heat treatment, all seamlessly connecting with the ceramic fiber preparation process through continuous stretching. Hydrophilic groups were introduced via surface modification enhancing the wettability of the fiber surface with the impregnating solution. An in-situ reaction and atom migration improve uniformity and binding of the coating. As a result, outstanding impregnation and adhesion properties are achieved. A comprehensive analysis to evaluate the impact of the BN coatings was conducted, which demonstrates that the BN-coated fibers exhibit a remarkable 36% increase in tensile strength, a 133% increase in fracture toughness, and enhanced temperature resistance of up to 1600°C. It provides a secure and efficient platform for the cost-effective production of functional and high-quality coatings through targeted surface modification and rapid stretching impregnation.