Reticulated foam structure

• US 3,946,039 A
• Filed: 08/11/1971
• Issued: 03/23/1976
• Est. Priority Date: 10/30/1967
• Status: Expired due to Term

• Current Assignee: Energy Research & Generation Incorporated
• Original Assignee: Energy Research & Generation Incorporated
• Inventors: Walz, Duane D.
• Primary Examiner(s): Marquis, Melvyn I.
• Application Number:
  US05/170,952
• Time in Patent Office: 1,686 Days
• Field of Search: 264/44, 264/59, 264/332, 75/222, 164/34, 164/113, 164/114, 164/246, 117/98 F, 117/138.8 D, 117/168
• US Class Current: 264/628
• CPC Class Codes: B22C 7/02 Lost patterns
• CPC Class Codes: B22C 7/023 Patterns made from expanded plastic materials
• CPC Class Codes: B22C 9/043 Removing the consumable pattern
• CPC Class Codes: B22D 25/005 Casting metal foams
• CPC Class Codes: B22D 29/002 by leaching, washing or dissolving
• 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: 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 38/0615 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

Method and manufacture are provided for preparing a reticulated foam structure by: investing an organic reticulated foam structure with an inorganic composition, which composition is inert under the conditions for forming the reticulated structure; allowing the inorganic suspension to set to form an investment; removing the organic reticulated foam structure; filling the voids of the investment with a fluid composition to form a reticulated casting; and dissolving the investment so as to leave a reticulated foam structure casting.

Claims

1. A method for manufacturing a reticulated foam structure which comprises:

investing a reticulated organic foam pattern uniformly with an inorganic investment composition containing an alkaline earth salt, oxide or hydroxide, or carbon and a resin from which the air is removed, which is settable to a structurally stable positive of said pattern;

allowing said inorganic investment composition to set to a form retaining investment;

removing said pattern from said investment, by thermal or chemical means, so as to leave a pattern of internal passageways in said investment corresponding to said organic foam pattern;

introducing a forming composition capable of forming cohesive solid structure into said pattern of internal passageways while maintaining a pressure differential across said investment and vibrating said investment, so as to form a solidus reticulated foam structure, wherein when said forming composition is a molten composition, said forming composition is maintained in a molten state to flow through said investment, and when said forming composition is a sinterable material, said investment is heated to at least the sintering temperature to form said solidus reticulated foam structure; and

removing said investment composition to leave a solidus reticulated foam structure of the solidified forming composition.

2. A method according to claim 1, wherein said reticulated foam structure has ligaments which are substantially the junctions of intersecting polyhedra.

3. A method according to claim 1, wherein said reticulated organic foam pattern is coated with at least one organic coating to form a pattern having ligaments of enhanced size.

4. A method according to claim 3, wherein said organic coating is wax.

5. A method according to claim 1, wherein said reticulated organic foam pattern has pore sizes of from 3 to 125 pores per inch.

6. A method according to claim 1, wherein said reticulated organic foam pattern is a polyurethane.

7. A method according to claim 1, wherein said reticulated organic foam pattern is wax.

8. A method according to claim 1, wherein said inorganic investment composition comprises at least one alkaline earth metal salt, oxide or hydroxide.

9. A method according to claim 1, wherein said inorganic investment composition comprises carbon.

10. A method according to claim 1 wherein said pattern is removed by heating at a temperature sufficient to melt or degrade said pattern.

11. A method according to claim 1, wherein said pattern is removed by hydrolysis with acid or basic catalysis.

12. A method according to claim 1, wherein said forming composition is a melt of metal, glass, ceramic or combination thereof and said conditions are cooling to form a reticulated foam structure of metal, glass, ceramic or combination thereof.