INVESTIGATION OF THE SEMISOLID MECHANICAL STIRRING METHOD TO DEPOSIT AN ALUMINUM PARTICLE COATING ON THE SURFACE OF SiC SHORT FIBERS

摘要

SiC short fibers, with an average diameter of 13 μm and length of 300–500 μm and chopped from SiC continuous fibers, were surface-modified by the semisolid mechanical stirring method to produce a discrete coating of aluminum particles. The SiC short fibers were introduced into semisolid state aluminum to prepare a slurry by the mechanical stirring method. As all of the short fibers were uniformly dispersed in the slurry, the temperature of the slurry was decreased as quickly as possible, but the slurry continued to be stirred until all of it was converted quickly into a powder-like composite. The surface morphology and axial section of the composite fiber and aluminum particles were examined using a scanning electron microscope (SEM) and an optical microscope; the element analysis of particles on the surface of short fibers in nanometer and submicron sizes was performed by Auger electron spectroscopy (AES). The results indicated that the powder-like composite was a mixture of pure aluminum powder and SiC short composite fiber, the surface of the composite fiber was coated by a discrete single layer of aluminum particles with nanometer, submicron and micron sizes, and the surface coverage of the aluminum particles on the surface of the short fibers ranged from 20 to 30%.