Nanocomposite powders from coating with heterogeneous nucleation processing

Abstract A nanocomposite SiC powder was prepared by coating nano-SiC particles with Y(OH) 3 and/or Al(OH) 3 via heterogeneous nucleation processing using a buffered pH solution as the precipitation reagent. TEM micrographs showed the coating materials nucleated and grew on the surface of nano-SiC and did not form sol particles in solution. The isoelectric point (IEP) of coated SiC was different from that of as-received SiC. The IEP of Al(OH) 3 -coated SiC occurred at pH 7.3, which is close to that of alumina. When Al(OH) 3 -coated SiC particles were coated with Y(OH) 3 ,the IEP of nanocomposite powder shifted from pH 7.3 to pH 8.6, which is close to that of yttria. In addition, the dispersability of Al(OH) 3 -coated SiC was greatly improved when it was coated using heterogeneous nucleation processing.