Molten metal filter medium and method for making same

• US 5,369,063 A
• Filed: 05/28/1992
• Issued: 11/29/1994
• Est. Priority Date: 06/27/1986
• Status: Expired due to Fees

• Current Assignee: Metaullics Systems Company LP (Pyrotek Incorporated)
• Original Assignee: Metaullics Systems Company LP (Pyrotek Incorporated)
• Inventors: Sane, Ajit Y., Krishnaswamy, Premachandran, Gee, Alison W.
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): MARCANTONI, PAUL D
• Application Number:
  US07/890,742
• Time in Patent Office: 915 Days
• Field of Search: 501/82, 264/DIG. 48, 264/43, 264/44, 210/751, 210/510.1, 524/404, 524/413, 524/430, 524/443
• US Class Current: 501/82
• CPC Class Codes: B01D 29/012 Making filtering elements making bag, cage, hose, tube, sleeve or like filtering elements B01D29/111
• CPC Class Codes: B01D 29/03 self-supporting
• CPC Class Codes: B01D 39/2093 Ceramic foam
• CPC Class Codes: C04B 38/00 Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof treating slag with gases or gas generating material C04B5/06 ; expanded graphite C04B35/536
• CPC Class Codes: C04B 38/065 characterised by physical aspects, e.g. shape, size or porosity
• CPC Class Codes: C22B 9/023 By filtering filtration of aluminium C22B21/066
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

A porous ceramic body of high structural strength and integrity is disclosed, along with the method of fabricating such, whereby a curable resin and a sinterable ceramic are mixed and then admixed to removable pore formers, then consolidated into a green body, the pore formers removed, and sintered into the porous ceramic body.

Claims

1. A green body, from which a porous ceramic body of high strength and integrity can be formed, comprising a consolidation of a predominantly homogenous mixture of a curable resin with a sinterable ceramic powder which is intermixed with a plurality of pore formers, the materials of said resin and said pore formers being selected such that the wetability of said resin in respect to said pore formers is such that said resin tends to bead when in contact with the surfaces of said pore formers, before said resin is cured, said resin in said consolidation which is cured and said pore formers in said consolidation which are removable after said resin in said green body has been cured.

2. The invention of claim 1 wherein said curable resin is selected from the group comprising polyester, epoxy, polyethylene, polypropylene, phenolic and polyvinylchloride.

3. The invention of claim 1 wherein said ceramic powder is selected from the group comprising Al₂ O₃, SiC, TiB₂, B₄ C, Si₃ N₄, SiAlON and partially stabilized zirconia.

4. The invention of claim 1 wherein said pore formers comprise wax.

5. The invention of claim 1 wherein said pore formers comprise CaCl₂.

6. The invention of claim 1 wherein said pore formers have lubricating properties.

7. The invention of claim 1 wherein the surfaces of said pore formers are coated with oil before being intermixed with said mixture of said curable resin with said sinterable ceramic powder.

8. The invention of claim 1 wherein said curable resin is mixed with a plasticizer before it is mixed with said sinterable ceramic powder.

9. The invention of claim 1 wherein said curable resin is mixed with a lubricant before it is mixed with said sinterable ceramic powder.

10. The invention of claim 1 wherein said curable resin is mixed with a curing agent before it is mixed with said sinterable ceramic powder.

11. The invention of claim 1 wherein said pore formers are predominantly spherical in shape.

12. The invention of claim 1 wherein said pore formers are predominantly non-spherical in shape.

13. The invention of claim 1 wherein said curable resin has lubricating properties.

14. The invention of claim 1 wherein said pore formers are removable by liquification.

15. The invention of claim 1 wherein said pore formers are removable by leaching.

16. The invention of claim 1 wherein said pore formers are removable by melting.

17. The invention of claim 1 wherein said pore formers are removable by pyrolization.

18. The invention of claim 1 wherein said pore formers are removable by sublimation.

19. The invention of claim 1 wherein predominantly each of said pore formers are in contact with at least two other of said pore formers.

20. A green body, from which a porous ceramic body of high strength and integrity can be formed, comprising a consolidation of a predominantly homogenous mixture of 30-80% by volume curable resin with 20-70% by volume sinterable ceramic powder which is intermixed with a pore former selected from the group consisting of calcium chloride, low melting point metals, urea, wax or a mixture thereof, before said resin is cured, said resin in said consolidation which is cured and said pore formers in said consolidation which are removable after said resin in said green body has been cured, said pore former, the materials of said resin and said pore formers being selected such that the wetability of said resin in respect to said pore forms is such that said resin tends to bead when in contact with the surfaces of said pore formers, comprising 64.2-75% by volume of said consolidation.