Specialized metallurgical processes – compositions for use therei – Processes – Producing or purifying free metal powder or producing or...
Patent
1992-12-10
1993-07-27
Wyszomierski, George
Specialized metallurgical processes, compositions for use therei
Processes
Producing or purifying free metal powder or producing or...
75366, 75370, 423440, B22F 926
Patent
active
052307298
ABSTRACT:
A new carbothermic reaction process is described for the thermochemical processing of nanophase WC-Co powders. The process permits shorter reaction times, reduced temperatures, and finer microstructures compared to conventional processing methods.
The process builds on our experience with spray conversion processing but involves 1) chemical vapor infiltration reaction of the carbon infiltrant using a carbon source gas at a carbon activity greater than or equal to 1.0 with the particle substrate to form WC-CO; and 2) removal of any excess (unreacted) carbon by controlled gasification using a gas with carbon activity less than 1.0. A feature of the carbothermic reaction process is its adaptability to conventional WC-Co processing technology, as well as to spray conversion processing technology.
The resulting power particles consist of a network of fine grains, (less than 100 nm) of WC and Co with interconnected fine porosity. Powder particles suitable for subsequent handling and consolidation are readily produced with diameters greater than 10 microns.
REFERENCES:
patent: 2160670 (1939-05-01), Oswald
patent: 2176802 (1939-10-01), Romp
patent: 3077385 (1963-02-01), Robb
patent: 3488291 (1970-01-01), Hardy et al.
patent: 3512962 (1970-05-01), Holtz
patent: 3932594 (1976-01-01), Gortsema
patent: 4320156 (1982-03-01), Oakes et al.
patent: 4579713 (1986-04-01), Lueth
patent: 4664899 (1989-05-01), Kimmel et al.
patent: 4851041 (1989-07-01), Polizzotti et al.
Gardner et al: Abstract, pp. 227-232, Precursor Chemistry Effects on Development of Particulate Morphology During Evaporative Decomposition of Solutions.
Halliday et al: Abstract, pp. 291-301, Thermodynamic Considerations of the Production of Coblat/Tungsten Carbide Mixture by Direct Gas Phase . . . .
R. Ushuima: Powder Metallurgy, vol. 11, No. 4., 1979.
Kear Bernard H.
Kim Byoung-Kee
McCandlish Larry E.
Rutgers The State University of New Jersey
Wyszomierski George
LandOfFree
Carbothermic reaction process for making nanophase WC-Co powders does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Carbothermic reaction process for making nanophase WC-Co powders, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Carbothermic reaction process for making nanophase WC-Co powders will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2339771