Abstract: Mixed oxide compounds La.sub.2 O.sub.3.11Al.sub.2 O.sub.3, NdAlO.sub.3 and nonstoichiometric MgAl.sub.2 O.sub.3 are suitable for making cores and molds for casting advanced superalloy materials such as NiTaC-13.

Abstract: A critical gas boundary layer Reynolds number has been defined to indicate processing conditions under which wide glassy alloy ribbons result when processing under various gaseous atmospheres and pressures and casting onto a moving substrate at an impingement angle .alpha..

Abstract: Metal wires of widths as small as 10 microns are migrated by thermal gradient zone melting processing as a molten zone through a body of semiconductor material. By calculating the width and thickness of the metal wires deposited on the wafer surface, improved uniform doped regions are produced. The method is restricted to the (100) planar orientation.

Abstract: When a body of semiconductor material is to be processed by thermal gradient zone melting, the outer peripheral side surface of the body is beveled to form an included angle .alpha. with the bottom surface of the body. The measure of the angle .alpha. is such that the radiant heat impinging on the beveled side peripheral surface is equal to the radiant heat emitted by the beveled side peripheral surface of the body.

Abstract: A thin opaque layer of material is deposited on one or both major opposed surfaces of a semiconductor wafer to enhance establishing a thermal gradient near the major surface or surfaces to produce straight, fine molten wires (<0.002") of a metal by migration of a melt of the metal through a solid, or matrix, both of semiconductor material by thermal gradient zone melting processing along a thermal gradient established and maintained aligned substantially parallel with a preferred crystal axis of migration by thermal gradient zone melting processing.

Abstract: A body of semiconductor material to be processed by thermal gradient zone melting (TGZM) has an outer side peripheral surface beveled at a predetermined included angle .alpha. with the bottom surface of the body in order that the radiant heat impinging on the beveled side peripheral surface is equal to the radiant heat emitted by the beveled side peripheral surface of the body.

Abstract: A wafer of semiconductor material processed by thermal gradient zone melting is supported by a beveled inner peripheral surface defining an aperture in a guard ring to minimize the distortion of the thermal gradient at the outer peripheral edge surface of the wafer.

Abstract: Thermal gradient zone melting (TGZM) is employed to make a semiconductor magnetoresistor device embodying a plurality of spaced highly conductive planar metallic-like electrodes formed in situ by TGZM to maximize the increase in the current path in a magnetic field established in the device.

Abstract: A core for investment casting directionally solidified eutectic and superalloy material consists of alumina which has a porous microstructure in which the grain morphology is characteristic of grains which have undergone vapor phase transport action.

Abstract: A semiconductor neuron comprises a tunnel diode having a region of recrystallized semiconductor material formed in situ in a columnar structure body of semiconductor material by thermal gradient zone melting. Individual electrical leads are affixed to the body and to both opposing faces of the recrystallized region. A voltage pulse applied between one pair of electrical leads on one surface across the P-N junction will propagate at a predetermined rate through the semiconductor body. After a predetermined delay, the applied pulse will appear across the P-N junction thereby mimicking the conducting nerve pulses by a biological nerve cell and its nerve fiber.

Abstract: Less than 3 weight percent of a rare earth metal is employed in doping a directionally solidified eutectic alloy or a superalloy material to minimize the formation of a metal-ceramic reaction layer during casting and solidification thereof.

Abstract: Cores made of either Y.sub.2 O.sub.3, Y.sub.3 Al.sub.5 O.sub.12, LaAlO.sub.3, MgAl.sub.2 O.sub.4 or Al.sub.2 O.sub.3 are removed from castings of advanced superalloy materials by immersion in a molten salt bath of either Li.sub.3 AlF.sub.6 or a mixture of CaF.sub.2 -NaF.

Abstract: Uniform initiation and migration of fine liquid wires by thermal gradient zone melting processing through a solid body of semiconductor material is enhanced by a heavily doped region of the body which includes the surface of initiation of the migration.

Abstract: Mutually perpendicular, intersecting, straight, fine molten wires, (.ltoreq.0.002" in width) can be migrated through a solid matrix body of semiconductor material of (100) planar orientation by migration along a unidirectional thermal gradient which is established and maintained at from 2.degree. to 10.degree. off the normally preferred <100> crystal axis of migration by the thermal gradient zone melting process. All the fine molten metal wires are substantially initiated simultaneously and uniformly along the entire length of each intersecting wire when the lines are arranged in a cross-hatched pattern.

Abstract: Aluminum is employed as a carrier metal for antimony in order to N-type dope semiconductor material by temperature gradient zone melting (TGZM) processing.

Abstract: A saturated or a supersaturated solution of the material of a solid body of semiconductor material in a layer of metal to be migrated by thermal gradient zone melting processing is utilized to achieve uniform penetration of fine lines (1 mil in width and less) and small droplets (less than 6 mils in diameter) in order to produce reliable semiconductor devices.

Abstract: Straight, fine molten wires (<0.002") of a metal can be migrated through a solid, or matrix, body of semiconductor material by initiation of the migration of the melt and continuing the migration along a thermal gradient established and maintained at from 2.degree. to 10.degree. off the normally preferred crystal axis of migration by the thermal gradient zone melting processing.

Abstract: Cores made of alumina-based ceramics, such as .beta.-alumina materials, are substantially non-reactive with directionally solidified eutectic and superalloy materials, do not cause hot cracking of the same, and are easily leachable from the cast metal.

Abstract: A composite substrate for use in a rotating x-ray anode tube consists of a graphite member joined to another member to which a target anode is affixed.

Abstract: A critical gas boundary layer Reynolds number has been defined to indicate conditions under which glassy alloy ribbons with serrated edges and surface perforations result when processing under various gaseous atmospheres and pressures.