Composite silicide/silicon carbide mechanical alloy

Details Composite silicide/silicon carbide mechanical alloy Composite silicide/silicon carbide mechanical alloy

1995-10-02

1997-06-17

Jordan, Charles T.

Powder metallurgy processes

Powder metallurgy processes with heating or sintering

Metal and nonmetal in final product

419 32, 419 38, 419 47, 419 48, 419 54, 419 60, 75236, 75255, 75351, 264DIG36, 501 92, C22C 104, C22C 110, B22F 314, B22F 900

Patent

active

056406665

ABSTRACT:
A method of producing a composite powder by providing particles of (I) tungsten, niobium, zirconium, titanium or mixtures thereof, (II) silicon and (III) carbon in a proportion relative to each other so as to possess an overall chemical composition in that segment of the ternary diagram of FIGS. 2(a), 2(b), 2(c) and 2(d) designated A, and subjecting the particles to a mechanical alloying process under conditions and for a time sufficient to produce the composite powder. Also disclosed is a method of forming a substantially oxygen-free composition of matter comprising a matrix substance of WSi.sub.2, NbSi.sub.2, ZrSi.sub.2, TiSi.sub.2 or alloys thereof having SiC dispersed therein, the method comprising consolidating the above-described composite powder. Also disclosed is a method of forming oxidation- and wear-resistant coatings by subjecting the composite powder whose composition lies in segment A to a metallurgical process such as plasma spraying. A method of forming a composite material of uniformly dispersed particles of silicon carbide in a silicide or an alloy silicide matrix is also disclosed. The matrix contains alloy silicides such as (Mo,W)Si.sub.2. The volume fraction of the silicon carbide may be varied from 10-90%. A method is also disclosed for producing hybrid composites consisting of a third phase of fibers or whiskers dispersed among a silicide/silicon carbide two-phase microstructure derived from the composite powder.

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