Process for producing a fiber aggregate

Abstract

The feature of the present invention is that a fiber mixture of silicon carbide or silicon nitride whiskers and alumina or alumina-silica short fibers with 1 to 45 volume percent of the short fibers in relation to the total volume of the whiskers and short fibers is used in the following steps for producing a fiber aggregate: a dispersion step of dispersing whiskers and short fibers into a dielectric fluid; an orientation step of placing the dielectric fluid containing the fibers dispersed therein in a space between a positive electrode and a negative electrode across which a high voltage is applied, whereby causing individual fibers in the dielectric fluid to electrostatically orient, with one end pointing to the positive electrode and the other end pointing to the negative electrode; and an aggregating step of aggregating the electrostatically oriented fibers while keeping the oriented step. The fiber mixture is used in order to grow the bridgings of whiskers around the short fibers as cores. Thus the fiber sedimentation is accelerated by densely bridged fibers while maintaining a satifactory orientation. Hence a whisker aggregate with a larger fiber volume ratio Vf can be formed in a shorter period of time.