Colloidal isopressing
OwnerFrederick F. Lange, Benjamin C. Yuinventors
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Abstract
Colloidal isopressing provides a rapid method to form an engineering shape from a powder slurry, previously filtered to remove strength degrading inclusions. A slurry composed of a weakly attractive particle network, produced with a short-range, repulsive interparticle par potential, is consolidated to make a body with a high particle density that is easily fluidized by vibration. The fluid-like body is injected into a flexible mold and subjected to a larger isostatic pressure to force particles into contact. This creates a strong, elastic body with the shape of the mold. Because the particles are forced into contact at a high pressure, the liquid remaining within the component can be removed by evaporation without shrinkage, avoiding fracture during rapid drying.
Claims28
A method of forming a part from a powder, comprising:
- forming a colloidal slurry containing particles of the powder suspended in a fluid;
- consolidating said slurry at a pressure below a critical value to obtain a consolidated body, wherein said critical value is a pressure below which the consolidated body can be made to flow,
- fluidizing the consolidated body such that the fluidized material is transferred into a flexible mold;
- subjecting the mold containing the fluidized material to isopressure above said critical value for a time sufficient for the fluidized material to convert to an elastic body;
- and
- removing the elastic body from the mold.
A method of forming a ceramic part from a ceramic powder, comprising:
- forming a colloidal slurry containing particles of the ceramic powder suspended in a fluid;
- consolidating said slurry by pressure filtration at a pressure below a critical value to form a consolidated body that can be made to flow, wherein said critical value is a pressure below which the consolidated body can be made to flow;
- fluidizing the consolidated body such that the fluidized material is transferred into a flexible mold;
- subjecting the mold containing the fluidized material to isopressure above said critical value for a time sufficient for the fluidized material to convert to an elastic body;
- and
- removing the elastic body from the mold.
Dependencies are inferred from the claim text.