Improvement of high-temperature resistance on carbon fiber felt/portland cement composite friction material by Al2O3 sol–gel coating

The extrusion impregnation method is used to prepare carbon fiber felt/portland cement (CFF/PC) composite materials. The samples are placed into muffle furnace for ablation, but carbon fiber is oxidized at around 450 °C. To improve the oxidation resistance of carbon fiber, Al 2 O 3 sol–gel (AS) is prepared to coat the surface of carbon fiber. The extrusion impregnation method is also used to prepare AS–CFF/PC composite materials. The samples are also ablated into muffle furnace at different temperatures. The results indicate that carbon fiber is uniformly dispersed and closely arranged in the matrix, presenting a three-dimensional network distribution. The bending and compressive strengths of CFF/PC composite materials are increased by 200% and 12% when compared with that of PC material at room temperature. The AS coating layer can effectively improve the antioxidant capacity of carbon fiber at high temperatures. The comparison reveals that AS–CFF/PC composite materials exhibit improved high-temperature resistance performance. Highlights CFF/PC and AS–CFF/PC composites were prepared by extrusion impregnation method. Sol–gel method was used to prepare different concentrations of Al 2 O 3 sol–gel (AS). AS coating layer can improve the antioxidant capacity of carbon fiber. AS–CFF/PC composites exhibit improved high-temperature resistance.