Abstract: A method for the preparation of ceramic composites containing at least aluminum oxide and aluminum boride, and the composite materials that result from the method. Intimate mixtures of finely-divided powdered aluminum metal and anhydrous boric oxide, with ratios (by weight) of about 0.5 to twenty parts of aluminum metal to one part of boric oxide, are subjected to a temperature to cause a complete reaction between the starting materials. If the ratio is above about 1.25 parts of aluminum to one part of boric oxide, the resultant product will include aluminum in addition to the aluminum oxide and aluminum boride. The ratio is selected to provide the desired hardness and toughness. Ratios between about 1 and 1.2 provide a composite having the highest hardness, with greater amounts of aluminum metal providing increased toughness. Several compositions are described, with hot pressing typically being used to provide the desired heating cycle.