Carbothermic reaction process for making nanophase WC-Co powders
A carbothermic reaction process is described for the production of nanophase metal/metal carbide particles comprised of the steps of: (a) preparing porous precursor particles by partial or full chemical reduction, the porous precursor powders acting as substrates for carbon infiltration, the preparation of precursor powder being effected by subjecting a solution of metal ions prepared from tungsten or cobalt compounds to a drying treatment selected from the group consisting of: spray calcining, spray roasting, spray drying, or freeze drying; (b) infiltrating the porous precursor particles with amorphous carbon from a carbon source gas or gas mixture at a carbon activity greater than or equal to 1.0, said carbon source gas being selected from the group consisting of CO, CO/CO[sub 2], CH[sub 4]/H[sub 2], and combinations thereof capable of achieving carbon deposition; said infiltrating of the porous precursor powders being achieved using low temperature catalytic decomposition of the selected gas or gas mixture by the precursor powder particle substrate; (c) simultaneously reacting the carbon from the source gas with the porous precursor powder particle substrates to form at least one carbide phase; (d) removing remaining unreacted carbon by gasification using a gas or gas mixture of carbon activity less than 1.0, the gas or gas mixture being selected from the group consisting of CO[sub 2], CO/CO[sub 2], CH[sub 4]/H[sub 2], or combinations thereof capable of removing carbon; said infiltrating and removing process steps being effected in a tube furnace, a muffle furnace, a belt furnace, a rotary kiln, a fluid bed furnace, or furnace suited for heating the precursor powder and gases to temperatures up to 1,000 C and achieving infiltration of carbon from a carbon source gas at a carbon activity greater than or equal to 1.0 and removal of unreacted carbon by gasification using a gas or gas mixture having a carbon activity less than 1.0.
- Assignee:
- Rutgers, The State Univ. of New Jersey, Piscataway, NJ (United States)
- Patent Number(s):
- US 5230729; A
- Application Number:
- PPN: US 7-989955
- OSTI ID:
- 6267330
- Resource Relation:
- Patent File Date: 10 Dec 1992
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COBALT
SYNTHESIS
COMPOSITE MATERIALS
TUNGSTEN CARBIDES
AQUEOUS SOLUTIONS
CARBON DIOXIDE
CARBON MONOXIDE
CHEMICAL REACTIONS
DECOMPOSITION
DRYING
FURNACES
GASIFICATION
HYDROGEN
IMPREGNATION
METHANE
MIXTURES
POROSITY
POWDER METALLURGY
PRECURSOR
REMOVAL
ALKANES
CARBIDES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
DISPERSIONS
ELEMENTS
HYDROCARBONS
MATERIALS
METALLURGY
METALS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
SOLUTIONS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN COMPOUNDS
400201* - Chemical & Physicochemical Properties