METHOD OF MAKING AN INORGANIC RETICULATED FOAM STRUCTURE

• US 3,616,841 A
• Filed: 10/30/1967
• Issued: 11/02/1971
• Est. Priority Date: 10/30/1967
• Status: Expired due to Term

• Current Assignee: Duane D. Walz
• Original Assignee: Duane D. Walz
• Inventors: Walz, Duane D.
• Primary Examiner(s): Arnold, Donald J.
• Assistant Examiner(s): Miller, John H.
• Application Number:
  US04/679,204
• Time in Patent Office: 1,464 Days
• Field of Search: 264/29,44,59,DIG.44 75/222 106/122 164/34,246
• US Class Current: 164/34
• CPC Class Codes: B22D 25/005 Casting metal foams
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/1121 by using decomposable, meltable or sublimatable fillers
• CPC Class Codes: B22F 3/1134 Inorganic fillers carbonaceous or paper filler B22F3/1121
• CPC Class Codes: B22F 3/1275 by coating a model and eliminating the model before consolidation
• CPC Class Codes: B28B 1/50 specially adapted for producing articles of expanded material, e.g. cellular concrete chemical aspects or making expanded aggregate C04B
• CPC Class Codes: C04B 35/00 Shaped ceramic products characterised by their composition porous ceramic products C04B38/00; ceramic articles characterised by particular shape, see the relevant classes, e.g. linings for casting ladles, tundishes, cups or the like B22D41/02; ceramic substrates for microelectronic semi-conductors H01L23/15; Ceramics compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides other than as macroscopic reinforcing agents C22C; shaping of ceramics B28B; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products chemical preparation of powders of inorganic compounds C01; infiltration of sintered ceramic preforms with molten metal C04B41/51
• CPC Class Codes: C04B 38/04 by dissolving-out added substances
• CPC Class Codes: C04B 38/0615 the burned-out substance being a monolitic element having approximately the same dimensions as the final article, e.g. a porous polyurethane sheet or a prepreg obtained by bonding together resin particles C04B38/0022 takes precedence
• CPC Class Codes: C22C 1/081 Casting porous metals into porous preform skeleton without foaming

Abstract

The production of foam material, e.g., a reticulated ceramic, metal or cermet material, is carried out by using commercially available conventional foam, such as reticulated polyurethane, having the desired pattern for the end product. This foam serves as a pattern for the mold and is embedded in mold material of plaster of paris or the like, which sets to form a solid structure in and around the plastic foam. This investment structure is then heated to volatilize and expel the plastic foam, leaving voids in the mold corresponding to the original configuration of the foam. Molten metal or other substance is then cast through the voids or openings in the mold and permitted to cool and set. The mold structure is then washed away, leaving a reticulated structure of integrally formed ligaments of metal, ceramic, cermet or other desired substance.

Claims

2. A method as set forth in claim 1 in which a pressure differential is created on different portions of said investment during the introduction of the molten substance therein, with said substance being introduced on the portion of greatest pressure.

3. A method as set forth in claim 2 in which said investment is subjected to a vacuum adjacent a portion thereof remote from the portion wherein the substance is being introduced.

4. A method as set forth in claim 2 in which said investment is subjected to gas pressure adjacent the portion thereof wherein the portion is being introduced.

5. A method as set forth in claim 4 in which said gas is selected from the group consisting of air and inert gases.

6. A method as set forth in claim 1 in which said investment is vibrated as the molten substance is poured therein.

7. A process in accordance with claim 1 wherein a temporary increase in the cross-sectional dimension of the ligaments of said foam is accomplished by coating said ligaments with a thin layer of a wax selected from dental wax, investment wax , or household parafin.

8. A process in accordance with claim 7 wherein the temporary increase in the cross-sectional dimension of the ligaments of said foam is accomplished by swelling said ligaments with a solvent.

9. A process in accordance with claim 8 wherein said solvent is trichorethylene.

10. A process in accordance with claim 1 wherein the insoluble molten material is molten aluminum.