Fluid casting of particle-based articles
AssigneeMartin Marietta Energy Systems, Inc.
InventorPaul Menchhofer
Life of this patent
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Abstract
A method for the production of articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with one aspect of the invention, a thermally settable slurry containing a relatively high concentration of the particles is introduced into an immiscible, heated fluid. The slurry sets or hardens into a shape determined by the physical characteristics of the fluid and the manner of introduction of the slurry into the fluid. For example, the slurry is pulse injected into the fluid to provide spherical articles. The hardened spheres may then be sintered to consolidate the particles and provide a high density product.
Claims14
A process for use in the production of articles of a desired shape from a particle-based material which comprises the steps of providing a thermally settable slurry having dispersed therein a relatively high concentration of the particles, a polymerizable and cross-linkable monomer, said particles being relatively inert with respect to said monomer, and a free-radical initiator compound for initiating the polymerization and cross-linking of the monomer, introducing the slurry into a displaceable fluid which yields to formably support the slurry in the desired shape and maintaining the temperature of the fluid at a temperature which is sufficient to cause heat transfer between the slurry and the fluid to initiate polymerization and cross-linking of the monomer, and coordinating maintenance of the temperature of the fluid with the introduction of the slurry into the fluid so that the slurry is maintained at the sufficient temperature for a time sufficient to enable the monomer in the slurry to polymerize and cross-link sufficiently to cause the slurry to set in the desired shape as a substantially self-supporting solid which is substantially rigid, removing the solid from the fluid, and sintering said solid.
A process for producing an essentially self-supporting solid article from a thermally settable slurry having at least one cross-linkable monomer, a free-radical initiator compound for initiating the polymerization and cross-linking of the monomer, a plurality of powder particles that are relatively inert with respect to the monomer, and a dispersant for dispersing said particles within the slurry, said method comprising the sequential steps of:
- introducing a preselected volume of the slurry into a fluid filled vessel;
- maintaining the temperature of the fluid at a temperature which is sufficient to cause a heat transfer between the slurry and the fluid, and coordinating maintenance of the temperature of the fluid with the introduction of the slurry into the fluid so that the slurry is maintained at the sufficient temperature for a time sufficient to enable the monomer in the slurry to polymerize and cross-link sufficiently to form a matrix while the volume of slurry is moving under the influence of gravity through the fluid such that the volume of slurry is transformed into an essentially solid cross-sectional article which is substantially rigid;
- removing the solid article from the fluid;
- and sintering the solid article.
A process of producing an essentially solid spherical-shaped article from a slurry containing a dispersion of particles used to make the article, said method comprising the steps of:
- introducing a thermally settable slurry containing the particles, a dispersant, one or more cross-linkable monomers, and a free-radical initiator compound for initiating the polymerization and cross-linking of the monomer, said particles being relatively inert with respect to the monomer, into a yieldably displaceable fluid which yields to formably support the slurry in the desired spherical shape;
- and
- maintaining the fluid at a predetermined temperature sufficient to cause a heat transfer between the slurry and the fluid produce a cross-linking reaction of the monomers and coordinating maintenance of the temperature of the fluid with the introduction of the slurry into the fluid so that the slurry is maintained at the sufficient temperature for a time sufficient to enable the monomer in the slurry to polymerize and cross-link sufficiently such that the slurry is rapidly formed into an essentially solid spherical-shaped self supporting article which is substantially rigid;
- removing the solid article from the fluid;
- and
- sintering the solid article.
Dependencies are inferred from the claim text.