Fabrication of Beryllium Oxide Radomes by Pyrolytic Deposition

摘要

An investigation was made of three forms of beryllium oxide, monolithic beryllia ceramic, foam structures, and structures reinforced with beryllia fibers. The pyrolytic method was investigated as a means of preparing dense beryllia and fibers of the oxide. Specifically, a chemical vapor deposition process involving a reaction between a halide of beryllium and water (hydro-pyrolytic reaction) and the pyrolysis of an organic adduct of beryllium were studied as means of preparing continuous deposits of beryllia. The vapor phase oxidation of beryllium metal was also investigated as a process for preparing beryllia fibers or whiskers. Deposits of limited thickness were prepared by the hydropyrolytic reactions involving oxygen donor systems such as either water or nitrogen dioxide. For either system, evidence points toward the fairly rapid attainment of equilibrium conditions wherein the deposit of beryllia produced by the reactions is eroded by the volatile non-metallic oxides of the reactants or products of the reactions. Preliminary results indicated that adherent, dense, and hard deposits of conceivably unlimited thickness could be prepared by the pyrolysis of a volatile organic adduct of beryllium. Sporadic success was attained in growing beryllia fibers by the vapor phase oxidation of beryllium metal.