Method of preparing a metal substrate for use in a catalytic converter

• US 4,300,956 A
• Filed: 04/14/1980
• Issued: 11/17/1981
• Est. Priority Date: 04/14/1980
• Status: Expired due to Term

• Current Assignee: Matthey Bishop Incorporated
• Original Assignee: Matthey Bishop Incorporated
• Inventors: Peters, Louis, Rosenberger, Gregory J.
• Primary Examiner(s): Shine, W. J.
• Application Number:
  US06/139,667
• Time in Patent Office: 582 Days
• Field of Search: 252/477 R, 72/147, 422/180, 428/906, 228/173 C, 228/193, 228/220, 228/231, 228/263 F, 148/6.3
• US Class Current: 148/285
• CPC Class Codes: B23K 20/00 Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
• CPC Class Codes: Y10T 428/1234 Honeycomb, or with grain orientation or elongated elements in defined angular relationship in respective components [e.g., parallel, inter- secting, etc.]

Abstract

Metallic bodies having discontinuously contacting sheet surfaces such as convolute-wound corrugated/non-corrugated metal sheet auto catalyst supports having metal-to-metal diffusion bonds formed at the contacting surfaces are provided. The diffusion bonds formed at the contacting surfaces are provided. The diffusion bonds are produced by heating the body in a non-oxidizing atmosphere, whereby metal from one surface diffuses into the metal from an adjacent surface. Some bonds may also be formed by welding. The bond-formation step may be performed in tandem with a subsequent step of oxidizing the sheet surfaces where they are not bonded, e.g. for making them into a more effectively-adhesive substrate for the catalyst they are to bear.

Claims

1. A method of preparing a metal substrate for use in a catalytic converter which comprises assembling together alternating layers of corrugated and non-corrugated sheets of metal alloy including aluminum as an alloy component so as to form an assembly wherein the layers have alternating areas of contact and non-contact;

and heating the assembly in an oven under a hydrogen atmosphere at a pressure of from about 0.5 to 5 micro-atmospheres and a temperature in the range of about 1000°

C. to about 1200°

C. until the layers are bonded together by metal-to-metal diffusion bonding at the points where the flat and corrugated sheets are in contact.

2. The process of claim 1 wherein the assembly, after the diffusion bonding, is heated in an oxygen atmosphere to oxidize the non-contacting surfaces of the assembly and form aluminum oxide thereon.

3. The process of claim 2 wherein the heating in the hydrogen atmosphere is carried out under vacuum at a pressure no greater than about 1 micro-atmosphere.

4. The process of claim 3 wherein the dew point in the oven is no greater than -120°

F.

5. The process of claim 1 wherein, after the diffusion bonding, the hydrogen is flushed out of the oven and the assembly is heated in an oxygen atmosphere to form aluminum oxide on the non-contacting surfaces of the assembly.

6. The process of claim 1 wherein the metal alloy comprises an alloy of iron, chromium, aluminum and yttrium in which the proportions lie in the range of up to 15% chromium, 0.5-12% aluminum and 0.1-3% yttrium, the balance being essentially iron.

7. The process of claim 1 wherein the sheets have a thickness of about 50 micrometers and the assembly is formed by rolling together alternating layers of corrugated and non-corrugated sheets of the metal alloys to form a cylindrical body.