Two classes of oxide systems, ZrO2 containing ceramics and MBa2Cu307-x (M=Y, Eu, Gd) superconductors, were melted and rapidly solidified by a variety of techniques. A crucibleless melting technique was used for all of the compositions. A twin roller solidification device generated materials with the highest quench rates, on the order of 10⁷ K/sec.

Al₂O₃-ZrO₂ eutectic and off-eutectic compositions, the Al₂O₃-Y₂O₃-ZrO₂ eutectic composition and two ternary eutectics in the Al₂O₃-MgO-ZrO2 system were examined. Amorphous and metastable crystalline materials were generated for all compositions. The microstructures generated for different compositions and cooling rates can be predicted by solidification theory. Annealing was performed under a range of thermal conditions, and compositional and microstructural changes were examined as the systems approached equilibrium. For the Al₂O₃-ZrO₂ and Al₂O₃-Y₂O₃-ZrO₂ eutectic compositions, devitrification occurred between 930-945°C with the nucleation of a ZrO₂ phase. In the Al₂O₃-MgO-ZrO₂ ternary eutectics, annealing the as-quenched, crystalline materials resulted in significant diffusion of Al₂O₃ and MgO, yielding complex phase assemblages.

The MBa₂Cu₃O_7-x compositions were melted with an H₂-0₂ torch with an O₂-rich flame. Significant reduction of the oxide was avoided by maintaining an overpressure of O₂ above the melt. Two metastable phases were found, amorphous materials and a previously unreported cubic phase, at the highest quench rates. The cubic phase does not have the 1:​2:​3 stoichiometry but is copper rich. The as-quenched materials are not superconducting, but must be annealed above 920°C in O₂. The phase development was identified through annealing experiments. The amorphous materials crystallize in a temperature range of 730-750°C. The peritectic decomposition temperatures of the Eu and Gd-1:​2:​3 compositions are 50°C higher than the Y-1:​2:​3. At low quench rates, the solidification path is complex as multiphase materials were generated. The annealed materials had excellent superconducting properties;​ a narrow transition width and a high T_c. Magnetic relaxation data indicate that the rapidly solidified materials have a narrower distribution of pinning sites than single crystals or materials produced through conventional powder processing techniques.