Importance

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Abstract

An aluminum nitride (AlN), alumina, magnesia, beryllia or other dielectric matrix with a ZrC dispersed phase is provided. Mixed powders of aluminum nitride or other dielectric phases and ZrC, with or without Y.sub.2O.sub.3, CaO, Li.sub.2O, La.sub.2O.sub.3, and other rare earth metal oxides or mixtures thereof are formed by dry pressing (or isostatic pressing, injection molding or other similar methods known to those familiar with the art). Consolidation at high temperatures (and or pressures) to a virtually dense material with densities of over 95%, preferably higher than 97% of theoretical density can be attained by hot pressing, hip-ing, gas-pressure sintering or pressureless sintering (including microwave sintering). A controlled inert atmosphere is required to prevent the oxidation or other reaction of the carbide phase. Ar or similar atmosphere is preferred to avoid reactions with ZrC. Materials produced according to the invention can have real dielectric constants in at least the 8-40 range, with the loss tangents ranging from 0.01-0.3 at 2 GHz. The materials described have lossy properties over a wide frequency range (0.5 to over 20 GHz), and at temperatures from 2 K to above room temperature.

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First Claim