Carbide/metal composite material and a process therefor
OwnerH. Tracy Hall, Jr., David R. Hallinventors
Life of this patent
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Abstract
A sintered product useful for abrasion- and impact-resistant tools and the like is provided comprising an iron-group metal binder and refractory metal carbide particles, e.g. tungsten carbide, formed in situ during sintering by the exothermic reaction of a carbide-forming refractory metal powder with a carbon source mixed therewith. The sintering is carried out at an elevated temperature and at a pressure at which diamond is stable in the presence of a liquid phase comprised substantially of an iron-group binder metal, refractory metal, and dissolved carbon. The product may optionally contain diamond, up to about 95% in volume, enabling its properties to be tailored for a wide range of applications.
Claims26
A method of forming a sintered product which comprises:
- providing a substantially uniform mixture comprising a hydrogen-reducible compound of a carbide-forming refractory metal and a carbon source material comprised substantially of diamond,
- subjecting said mixture to hydrogen reduction at an elevated temperature conducive to the reduction of said compound, thereby producing a reduced mixture comprising particles of reduced refractory metal and particles of said diamond,
- forming a dense compact of said reduced mixture,
- subjecting said compact to sintering in the presence of an iron-group binder metal at a temperature at which a liquid phase forms comprising said iron-group binder metal, said carbide-forming refractory metal, and carbon, and at a pressure at which diamond is stable,
- continuing said sintering to form by reaction refractory metal carbide in situ,
- said liquid phase being distributed through said compact during said sintering,
- and cooling said compact to provide a sintered product comprising particles of said in situ produced refractory metal carbide and said binder metal.
A method of forming a sintered product which comprises:
- providing a compact formed of a substantially uniform mixture of particles of tungsten metal and a carbon source material selected from the group of diamond, non-diamond carbon, and mixtures thereof,
- subjecting said compact to sintering in the presence of cobalt metal at a temperature at which a liquid phase forms
- comprising said cobalt, said tungsten, and carbon, and at a pressure at which diamond is stable,
- continuing said sintering to form by reaction tungsten carbide in situ,
- and cooling said compact to provide a sintered product comprising said cobalt and said in situ produced tungsten carbide,
- wherein said carbon source material is provided in an amount substantially equal to or in excess of the maximum reactive capacity of said tungsten metal with carbon at said conditions of temperature and pressure, any free carbon remaining after said sintering being present substantially as diamond, said diamond ranging in amount from about 0% to about 95% by volume, the balance comprising said tungsten carbide and said cobalt.
A method of forming a sintered product which comprises:
- providing a substantially uniform mixture of a compound selected from the group consisting of tungsten trioxide and ammonium paratungstate,
- a carbon source material comprised substantially of diamond,
- and a compound selected from the group consisting of cobalt hydroxide and hydrated basic cobalt carbonate,
- subjecting said mixture to hydrogen reduction, thereby producing a reduced mixture comprising particles of reduced tungsten metal, diamond, and reduced cobalt metal,
- forming a dense compact of said reduced mixture,
- subjecting said compact to sintering at a temperature at which a liquid phase forms comprising said cobalt, said tungsten, and carbon, and at a pressure at which diamond is stable,
- continuing said sintering to form by reaction tungsten carbide in situ,
- and cooling said compact to provide a sintered product comprising particles of said tungsten carbide and said cobalt,
- wherein said carbon source material is provided in an amount substantially equal to or in excess of the maximum reactive capacity of said reduced tungsten metal with carbon at said conditions of temperature and pressure, any free carbon remaining after said sintering being present substantially as diamond, said diamond ranging in amount from about 0% to about 95% by volume, the balance comprising said tungsten carbide and said cobalt.
Dependencies are inferred from the claim text.