Production of sintered moldings

• US 5,611,978 A
• Filed: 08/10/1995
• Issued: 03/18/1997
• Est. Priority Date: 05/04/1993
• Status: Expired due to Term

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Truebenbach, Peter
• Primary Examiner(s): Fiorilla, Christopher A.
• Application Number:
  US08/492,117
• Time in Patent Office: 586 Days
• Field of Search: 264/63, 264/82, 419/44
• US Class Current: 264/656
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 1/103 containing an organic binding agent comprising a mixture of, or obtained by reaction of, two or more components other than a solvent or a lubricating agent
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/1025 not by heating only
• CPC Class Codes: B22F 3/225 by injection molding
• CPC Class Codes: C04B 35/63452 Polyepoxides
• CPC Class Codes: C04B 35/638 Removal thereof

Abstract

Sintered moldings are produced by molding a mixture of a sinterable ceramic or metallic powder and polyoxymethylene or a copolymer containing a majority of oxymethylene units as binder to give a compact, removing the binder by treatment with a gaseous acid, and sintering the product, which comprises removing the binder using an acid which is solid at room temperature and sublimes or melts and evaporates at elevated temperatures.

Claims

1. A process for the production of sintered moldings which comprises:

molding a mixture of a sinterable ceramic or metallic powder and polyoxymethylene or a copolymer containing a majority of oxymethylene units as binder to give a compact, removing the binder by treatment with a gaseous acid,a nd sintering the molding wherein the acid is solid at room temperature and sublimes or melts and evaporates when heated.

2. The process of claim 1, wherein the binder is removed using acids having a sublimation or melting point of between 25 and 200°

C.

3. The process of claim 2, wherein the binder is removed using anhydrous oxalic acid or oxalic acid dihydrate.

4. The process of claim 2, wherein the binder is removed at atmospheric pressure or under reduced pressure.

5. The process of claim 1, wherein the binder is removed using anhydrous oxalic acid or oxalic acid dihydrate.

6. The process of claim 5, wherein the binder is removed at atmospheric pressure or under reduced pressure.

7. The process of claims 1, wherein the binder is removed at atmospheric pressure or under reduced pressure.