Preparation of SiC coated carbon fiber based on rayon using psiprocesses

摘要

Based on high-strength rayon fiber, continuous SiC-coated carbon fibers were prepared. A chemical treatment using an amines-containing aqueous solution enables the fiber to be pyrolyzed at much higher heating rate. Multi-step pyrolysis accompanied with polymer solution infiltration processes using polycarbosilane solution was carried out. The pyrolysis temperature is up to 1000. The kinetics of the pyrolysis was investigated and a new model was proposed, with which, the pyrolysis procedure was established. The yield of the C/SiC fibers is 35-38 percnet. The tensile strength of the fiber is 1.3-2.0GPa, Young's modulus of 70-130 GPa and average fiber diameter of 4 to 6 #mu#. Since the carbon and the exterior SiC are formed from the corresponding organic precursors at high temperature, the interface of C and SiC is formed by a strong linking and in a graduation form, with SiC infiltrated into the inner part of the fiber.