Preparation of silicon-nitride ceramic fibers with hafnium compounds loaded on the surface and the high temperature properties

Abstract

The surface and core are composed of heterogeneous fiber materials that are endowed with excellent properties due to the unique structure. In this work, polysiloxane (PSZ) was used as the ceramic precursor and hafnium carbide (HfC) was used as the hafnium source, and Si–N–C–O-Hf hybridized ceramic fibers were obtained using electrostatic spinning and pyrolysis. After the primary fibers were pyrolyzed at 1400 °C, hemispherical particles were found on the surface of the ceramic fibers. And the average fiber diameters were around 3 μm. Thermogravimetric analysis (TGA) showed that the mass of the cured fibers decreased to 67 % below 1650 °C in an argon atmosphere. The mass of the ceramic fibers remained almost unchanged in the high temperature aerobic environment. Meanwhile, the thermal conductivity of the specimens has remained relatively low. Analytical tests confirmed that the hafnium-containing hemispherical protective layer gave the specimens excellent thermal stability, oxidation resistance, and high temperature insulation. In addition, the excellent mechanical properties make it suitable for a wide range of applications. The optimized high-temperature performance and mechanical properties indicate that metal-hybridized silicon-based ceramic fibers herein are suitable for ultra-high-temperature environments.