United Technologies Corporation

Romeo G Bourdeau

Roscoe A Pike

Robert A Metcalfe

George K Layden, Jr

Francis S Galasso

Arthur R Cox

Paul R Holiday

A process for producing binderless, single phase bulk carbon or graphite articles having a fibrillar microstructure comprising the steps of assembling a plurality of polymer fibers into a preselected pattern, subjecting them to a temperature and pressure sufficient to cause heat distortion flow and concomitant self-bonding of contiguous fibers and pyrolyzing the fibers in a nonoxidizing atmosphere.

Process for producing binderless carbon or graphite articles

In the process of forming metal powders by rotary atomization, the atomizer disk is first coated with a stable compound of the molten metal to be poured or, if the metal to be poured is an alloy, the disk is coated with a compound of the base metal of the alloy. The coating compound is selected on the basis of its melting point and that it can coexist with the molten metal to be poured, at the pour temperature, as indicated by phase diagrams of the materials involved. The molten metal is poured onto the coated, spinning disk, couples with the coating, and forms a stable skull of itself over the coating. Fine droplets of molten metal are thereafter flung from the disk, cooled and collected.

Rotary atomizing process

Binderless carbon or graphite articles

Disclosed is an improved tool bit having 7 to 36 mole percent cubic boron nitride together with a metal carbide in a matrix containing a transition metal and a reactive metal sintering aid. A preferred tool bit consists by atomic percent of 52-79 tungsten carbide, 7-36 cubic boron nitride, 9-14 cobalt, and 0.2-2.5 zirconium. The new bits provide up to four times more life than tungsten carbide cobalt bits in machining nickel superalloys and are less costly than wholly cubic boron nitride bits. Tool bits containing tungsten carbide and cubic boron nitride particulates are fabricable at relatively moderate hot pressing pressures and temperatures (7-28 MPa, 1350.degree.-1500.degree. C.) if included therein is a sintering aid selected from the group consisting of titanium, zirconium, hafnium, aluminum or mixtures thereof. The aforementioned reactive metal aids are preferably added as hydrides.

Cubic boron nitride and metal carbide tool bit

A series of superalloy compositions are described, which when processed according to a described processing sequence, produce homogeneous superalloy articles which contain an exceptionally high amount of the gamma prime phase. These alloys contain large amounts of aluminum and chromium and hence are quite oxidation resistant. The processing sequence includes rapid solidification to suppress the formation of the low melting eutectic phases which would otherwise occur.

High gamma prime superalloys by powder metallurgy

An apparatus is set forth wherein powder is produced by melting metal in a melting furnace and then directing it onto an atomizer rotor or cup. The atomizer cup is positioned to receive molten metal at the center thereof and is rotated by any means desired. The cup comprises an outer metal cup fixed to the top of a rotating shaft, with an inner cup mounted in the center thereof and spaced therefrom by an outwardly extending flange at the top. A low conductivity thermal insulation is provided between the cups, and the inner cup is coated with a ceramic such as by plasma or flame spray. The inner cup is tapered inwardly as it extends from its bottom to the top edge to provide an annular pool of molten metal around the inner surface permitting the liquid metal to attain the peripheral speed fo the spinning cup as it moves from the center of the cup to the top edge. A heater is provided to preheat the cup and during operation to aid in keeping the cup surface above the melting point of the liquid metal. This will help prevent premature freezing of the liquid metal before it reaches the quenching medium into which the particles are being thrown.

Spin cup means for the production of metal powder

A rotary liquid metal atomizer is positioned to receive a stream of molten metal on the top thereof. The atomizer is formed as a hollow disc means having a concave top surface and mounted for rotation at high R. P. M.'s on the top of a hollow drive shaft. A circular coolant baffle is located in the hollow disc means, for cooling fluid to flow around, and is mounted on the top of an inlet cooling tube located within the drive shaft. Cooling fluid is directed through the inlet cooling tube to the top of the water baffle where it flows through a hole in the center thereof and around the space between the baffle and the interior of the hollow disc means and down between the inlet cooling tube and drive shaft. The top of the disc means over the coolant baffle is formed of copper. A metal rim is placed around the upper outer periphery of the copper disc forming a recessed center portion. A ceramic coating is placed in the recessed portion with its outer edge against the inside of the rim. The metal rim acts to hold the coating against centrifugal force and to provide a material for the liquid metal to melt and form a fusion weld therewith to firmly attach a controlled solidified metal skull to the atomizer.

Rotary atomization means for the production of metal powder

Method of producing solid particles of metal

A process for producing continuous filaments from polyamic acid suitable for conversion to polyimide filaments comprising providing a starting solution consisting essentially of equimolar amounts of P,P-diaminophenyl ether and bis-(3,4-dicarboxyphenyl) sulfone dianhydride, the remainder a solvent selected from the group consisting of dimethylformamide, methyl pyrrolidone and mixtures thereof, said starting solution having a viscosity ranging from 500 to 5,000 centipoises preferably 1,500 to 3,000 centipoises, and forming the starting solution into filaments by extruding it in a coagulating bath consisting essentially of a liquid selected from the group consisting of propanol, methyl alcohol, ethyl alcohol, butyl alcohol, a mixture of ethyl alcohol and propanol and a mixture of methyl alcohol and acetone.

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Tequesta, FL, United States of America

Romeo G Bourdeau