Abstract: A metal oxide barrier layer is provided at the interface between a refractory oxide-silica investment mold and a contained metal superalloy, allowing directional solidification of the contained superalloy at elevated temperatures without metal-mold reaction.

Abstract: A varistor has a lamellar structured body of semiconductor material. The lamellar structure is produced by migrating "wires" of metal by a temperature gradient zone melting process to form a plurality of alternate regions of opposite type conductivity in a substrate and a P-N junction at the contiguous surfaces of each pair of regions of opposite type conductivity. The material of the regions formed by the migrated wires is recrystallized semiconductor material of the body suitably doped to form a selected type conductivity and resistivity.

Abstract: A varactor has a lamellar structure of a plurality of abutting regions of alternate and opposite type conductivity. The structure is produced by thermal gradient zone melting processing.

Abstract: A solar cell with improved efficiency is provided with a convoluted P-N junction whereby a higher proportion of carriers produced by exposure of the solar cell to a source of radiation will be collected by the P-N junction rather than being lost by recombination. The solar cell has an increased resistance to radiation damage. The solar cell is made from a body of semiconductor material in which two regions of opposite type conductivity are formed. The material of one region is substantially the same as the body and the material of the other region is recrystallized material of the first region having solid solubility of a metal therein to impart a selective type conductivity and resistivity thereto.