Diffusion bonded metallic catalyst carrier and production thereof

• US 6,761,857 B1
• Filed: 02/22/2000
• Issued: 07/13/2004
• Est. Priority Date: 03/16/1998
• Status: Expired due to Fees

• Current Assignee: Nippon Steel Corporation
• Original Assignee: Nippon Steel Corporation
• Inventors: Otani, Tadayuki, Takahashi, Yasuo, Kasuya, Masayuki, Iwami, Kazutoshi
• Primary Examiner(s): TRAN, HIEN THI
• Application Number:
  US09/423,944
• Time in Patent Office: 1,603 Days
• Field of Search: 422/171, 422/177, 422/180, 422/222, 422/211, 428/593, 298/90, 228/181
• US Class Current: 422/180
• CPC Class Codes: B01J 35/56 Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: B23K 20/02 by means of a press ; Diffusion bonding B23K20/001, B23K20/04 take precedence
• CPC Class Codes: B23K 2101/02 Honeycomb structures
• CPC Class Codes: B23K 2103/05 Stainless steel
• CPC Class Codes: F01N 13/0097 the purifying devices are arranged in a single housing
• CPC Class Codes: F01N 2330/04 Methods of manufacturing
• CPC Class Codes: F01N 2330/321 with two or more different kinds of corrugations in the same substrate
• CPC Class Codes: F01N 2330/322 Corrugations of trapezoidal form
• CPC Class Codes: F01N 2450/22 by welding or brazing
• CPC Class Codes: F01N 3/281 Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates
• 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

A honeycomb body, which is composed in such a manner that a strip of corrugated foil made of heat-resistant stainless steel containing aluminum and a strip of flat foil made of stainless steel are alternately wound or laminated on each other, is incorporated into an outer cylinder made of metal and integrated into one body by means of diffusion bonding, so that a diffusion bonded metallic catalyst carrier can be formed. Surface roughness of the strip of foil after the completion of diffusion bonding is 0.001 to 2.0 μm when it is expressed by center line average height Ra, and no sintered bridges are formed at both end portions of the diffusion bonded section in the longitudinal direction. The catalyst carrier is manufactured in a condition so that λb, which is defined by

λb=6.8×10⁻¹²×δf⁻¹×F^1/2×Ra^−1/2×T^1/4×exp(15000/T)×b^1/2,

can be in a range from 8 to 20 where thickness of the strip of foil is δf (m), average roughness of the foil surface is Ra (m), back tension in the case of winding is F (kgf), contact width of the piece of flat foil with the piece of corrugated foil is b (m), heat treatment temperature is T (K), and degree of vacuum is Pout (Pa), under the condition that 7.52×10⁹×exp(−35000/T)≧8×Pout.

Claims

1. A diffusion bonded metallic catalyst carrier comprising:

a honeycomb body composed of a piece of corrugated foil made of heat-resistant stainless steel containing aluminum and a piece of flat foil or corrugated foil made of stainless steel, the piece of corrugated foil and the piece of flat foil or corrugated foil being alternately wound or laminated on each other; and

an outer cylinder made of metal into which the honeycomb body is incorporated, the honeycomb body and the outer cylinder being integrated into one body by means of diffusion bonding,

wherein the pieces of foil have a surface roughness in a width direction of the foil after diffusion bonding wherein an arithmetical mean deviation of asserted profile Ra after diffusion bonding is 0.001 to 2.0 μ

m, and

diffusion bonds forming joint sections between two pieces of foil of the corrugated foil and the flat foil or the corrugated foil with no sintered bridges formed at both end portions of the joint sections in the longitudinal direction of the pieces of foil;

wherein the catalyst carrier has an exhaust gas entry side and an exhaust gas delivery side,

solder bonds are located at contact portions of the piece of corrugated foil and the piece of flat foil or corrugated foil at the exhaust gas entry side; and

diffusion bonds are located at the contact portions of the piece of corrugated foil and the piece of flat foil or corrugated foil at the exhaust gas delivery side.

2. A diffusion bonded metallic catalyst carrier according to claim 1,

wherein the honeycomb body comprises the piece of corrugated foil and the piece of flat foil, and

wherein the piece of corrugated foil at the exhaust gas entry side of the catalyst carrier has a wave form in a trapezoid shape and area of contact between the piece of flat foil and the trapezoid shape wave form of the piece of corrugated foil at the exhaust gas entry side is large, and the piece of corrugated foil at the exhaust gas delivery side of the catalyst carrier has a wave form configuration wherein area of contact between the piece of flat foil and the configuration of the wave form of the piece of corrugated foil at the exhaust gas delivery side is not large.

3. A diffusion bonded metallic catalyst carrier according to claim 1,

wherein the honeycomb body comprises the piece of corrugated foil and the piece of flat foil, and

wherein the piece of flat foil has a thickness which is not uniform, wherein the thickness of the piece of flat foil at the exhaust gas entry side of the catalyst carrier is large and the thickness of the piece of flat foil at exhaust gas delivery side of the catalyst carrier is small.

4. A method of manufacturing a diffusion bonded metallic catalyst carrier, the diffusion bonded metallic catalyst carrier comprising:

a honeycomb body composed of a piece of corrugated foil made of heat-resistant stainless steel containing aluminum and a piece of flat foil or corrugated foil made of stainless steel, the piece of corrugated foil and the piece of flat foil or corrugated foil being alternately wound or laminated on each other; and

an outer cylinder made of metal into which the honeycomb body is incorporated, the honeycomb body and the outer cylinder being integrated into one body by means of diffusion bonding,

the method of manufacturing the diffusion bonded metallic catalyst carrier comprising the step of selecting parameters so that λ

b, which is defined by

5. A method of manufacturing a diffusion bonded metallic catalyst carrier according to claim 4, wherein surface roughness Rac (m) of the foil in a width direction of the foil is used as a replacement for arithmetical mean deviation of asserted profile Ra (m).

6. A method of manufacturing a diffusion bonded metallic catalyst carrier according to claim 4, wherein arithmetical mean deviation of asserted profile Ra of the surface of the foil before diffusion bonding is 0.001 to 3.0 μ

m.

7. A method of manufacturing a diffusion bonded metallic catalyst Carrier according to claim 4, wherein λ

b is in a range of from 14 to 18.

8. A method of manufacturing a diffusion bonded metallic catalyst carrier according to claim 4, wherein the constant of proportion C=6.8×

10<sup>−

12</sup>.