Specialized metallurgical processes – compositions for use therei – Processes – Producing or purifying free metal powder or producing or...
Patent
1992-10-02
1994-10-11
Sheehan, John P.
Specialized metallurgical processes, compositions for use therei
Processes
Producing or purifying free metal powder or producing or...
420 83, 420121, 420418, 148101, 148669, B22F 926
Patent
active
053543548
ABSTRACT:
A method for producing single-phase intermetallic phases, which melt incongruently within a temperature range of 900.degree. to 2,000.degree. K., with a homogeneity range of .ltoreq.10 atom % at room temperature by co-reduction is described. The exothermic reaction of the calciothermal reduction is adjusted by altering the oxide content of the reaction mixture, the composition of which corresponds to the desired single-phase alloy, in such a way that the temperature condition T.sub.m >T.sub.R .gtoreq.0.9 T.sub.m (in .degree. K.) is fulfilled, T.sub.m being the melting temperature of the intermetallic phase and T.sub.R the reaction temperature. The components of the reaction mixture, with the exception of calcium, have an average particle size of .ltoreq.75 .mu.m. The reaction product at the end of the exothermic reaction is tempered at a temperature which is at least 0.7 times the melting temperature T.sub.m of the desired, single-phase alloy, measured in .degree. K., but is less than the melting temperature T.sub.m, during a period sufficient for the diffusion of the components.
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Edeling Martin
Eggert Horst
Steinhorst Michael
Sheehan John P.
Th. Goldschmidt Ag
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