controlled heat schedule an example of such a schedule is as follows after two hours under 200 psi pressure and 350 u00b0 f 177 u00b0 c a typical u215b inch thick fiber reinforced molded panel is heat treated at the following heat schedule for optimal ceramic performance properties heat from 350 u00b0 f 177 u00b0 c to about 960 u00b0 f 515 u00b0 c at about 212 u00b0 f 100 u00b0 c hour then raise from 960 u00b0 f to 2000 u00b0 f 1093 u00b0 c at about 50 u00b0 f 10 u00b0 c hour then raise from about 2000 u00b0 f 1093 u00b0 c to about 2300 u00b0 f 1260 u00b0 c then hold for about 2 hours at about 2300 u00b0 f 1260 u00b0 c a variety of polysiloxane oligomers that are well known in the art such as those commercially available from dow corning general electric and others can be used to formulate the polysiloxane resin containing the boron nitride and impregnating the ceramic fibers or fabric for composite molding and ceramic processing the silicon matrix used in this invention is essentially an elastomer when heat treated to 350 u00b0 f 177 u00b0 c a thermoset to 700 u00b0 f 371 u00b0 c a green ceramic to 1300 u00b0 f 704 u00b0 c and a ceramic to 2300 u00b0 f 1260 u00b0 c as a result its properties fall between those of elastomers and ceramics depending upon the temperature to which the composite is heat treated the formulation is adjusted to provide fiber impregnation and composite molding advantages the storage life as ambient temperature for the resin has been found to.