Method of making articles from sinterable materials
AssigneeSolid Micron Materials, Pte, Ltd.
InventorRomain L. Billiet
Life of this patent
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Abstract
A method of binder removal from a green body before sintering or the like wherein the binder is constituted of a polymeric material or mixture which is degradable by thermo-oxidation and the green body is initially heated to a temperature where the binder reaches an energy level above the activation energy of the binder, as a result of which exothermic degradation reactions are initiated at the binder-atmosphere interface. The rate of the exothermic reaction is controlled by the rate of supply of thermal energy and oxygen to the reaction site as well as the rate of evacuation of the heat of reaction generated during the thermal oxidation. Substantially all of the binder is thus removed from the green body which can then be sintered in accordance with the practices of the prior art.
Claims19
A method of producing an article from sinterable particulates whereby binder material is removed from a molded configuration prior to firing, comprising the steps of:
- (1) mixing together predetermined amounts of sinterable particulates and an organic binder at a temperature above the melting point of the binder whereby a mixture is formed wherein said binder covers substantially all of the surface of said sinterable particulates,
- (2) forming said mixture into a desired configuration,
- (3) rapidly increasing the temperature of said configuration in an oxygen bearing atmosphere to a temperature where said binder will enter into a reaction to cause exothermic degradation,
- (4) detecting and then limiting said exothermic degradation by controlling the amount of heat and oxygen furnished to the reaction whenever exothermic degradation is initiated,
- (5) continuing heating until substantially all of said binder is removed from said configuration, and
- (6) sintering said configuration.
A method of removing fugitive organic binders from a molded or compacted green body of sinterable particulates comprising,
- (a) heating a green body article in an oxygen bearing atmosphere, the green body article having sinterable particulates in an organic binder, then
- (b) detecting exothermic reactions in said green body article at the interface of said green body article and said oxygen bearing atmosphere, than
- (c) quenching said exothermic reactions, then
- (d) repeating steps (a)-(c) until the exothermic reactions of step (b) are no longer detected after the heating of step (a).
A method of removing fugitive organic binders from a molded or compacted green body of sinterable particulates comprising,
- (a) heating a green body article in an oxygen bearing atmosphere, the green body article having sinterable particulates in an organic binder, said heating progressing at a rate for the purpose of initiating exothermic degradation of said organic binder, then, detecting the attainment of exothermic degradation of said organic binder, then
- (b) cooling said green body after attaining the exotherm of said organic binder, said cooling halting said exothermic degradations,
- (c) repeating steps (a) and (b) until exothermic reactions no longer occur in said green body article.
A method of producing an article from sinterable particulates whereby binder material is removed from a molded configuration prior to firing, comprising the steps of:
- (1) mixing together predetermined amounts of sinterable particulates and an organic binder at a temperature above the melting point of the binder whereby a mixture is formed wherein said binder covers substantially all of the surface of said sinterable particulates,
- (2) forming said mixture into a desired configuration,
- (3) rapidly increasing the temperature of said configuration in an oxygen bearing atmosphere to a temperature where said binder will enter into a reaction to cause exothermic degradation, said oxygen bearing atmosphere being provided by a fluid flow of gaseous oxidant from a downstream position and in an upstream direction,
- (4) limiting said exothermic degradation by controlling the amount of heat and oxygen furnished to the reaction whenever the initiation of exothermic degradation is detected by the occurrence of measuring the temperature at a location in close proximity to the configuration on a downstream side thereof as exceeding the temperature measured closely proximate the configuration at a side upstream relative to said fluid flow of gaseous oxidant,
- (5) continuing heating until substantially all of said binder is removed from said configuration, all
- (6) sintering said configuration.
Dependencies are inferred from the claim text.