Metal and ceramic heat-connected body

• US 5,066,547 A
• Filed: 07/24/1989
• Issued: 11/19/1991
• Est. Priority Date: 02/18/1985
• Status: Expired due to Fees

• Current Assignee: NGK Spark PLUG Company Limited
• Original Assignee: NGK Spark PLUG Company Limited
• Inventors: Ito, Masaya, Ishida, Noboru, Kawamura, Mitsuyoshi
• Primary Examiner(s): Dean, R.
• Assistant Examiner(s): Wyszomierski, George
• Application Number:
  US07/385,991
• Time in Patent Office: 848 Days
• Field of Search: 428/627, 428/632, 428/680, 428/684, 428/685, 428/450, 428/457, 428/469, 228/122, 228/903, 148/144, 420/60, 420/61, 416/241 B
• US Class Current: 428/627
• CPC Class Codes: C04B 2235/6565 Cooling rate
• CPC Class Codes: C04B 2235/6581 Total pressure below 1 atmosphere, e.g. vacuum
• CPC Class Codes: C04B 2237/123 based on iron group metals, e.g. steel
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 2237/365 Silicon carbide
• CPC Class Codes: C04B 2237/368 Silicon nitride
• CPC Class Codes: C04B 2237/406 Iron, e.g. steel
• CPC Class Codes: C04B 2237/64 Forming laminates or joined articles comprising grooves or cuts
• CPC Class Codes: C04B 2237/76 Forming laminates or joined articles comprising at least one member in the form other than a sheet or disc, e.g. two tubes or a tube and a sheet or disc
• CPC Class Codes: C04B 2237/78 Side-way connecting, e.g. connecting two plates through their sides
• CPC Class Codes: C04B 37/021 in a direct manner, e.g. direct copper bonding [DCB]
• CPC Class Codes: C04B 37/026 consisting of metals or metal salts
• CPC Class Codes: F01D 5/025 Fixing blade carrying members on shafts attachment of a member on a shaft in general F16D1/06; for non-positive displacement pumps F04D29/00
• CPC Class Codes: F02F 7/0087 Ceramic materials
• CPC Class Codes: F05D 2300/5021 Expansivity
• CPC Class Codes: Y10S 228/903 Metal to nonmetal
• CPC Class Codes: Y10T 428/12576 Boride, carbide or nitride component
• CPC Class Codes: Y10T 428/12611 Oxide-containing component
• CPC Class Codes: Y10T 428/12979 Containing more than 10% nonferrous elements [e.g., high alloy, stainless]

Abstract

In heat-connection between metal and ceramic, martensite stainless steel or martensite heat-resistant steel which can be hardened a gas or vacuum after having been heated beyond the quenching temperature thereof are used as metal. The heat connection is brazing or shrinkage fit at 800° C. or more. Stress strain caused by a difference in thermal expansion coefficient between the two can be reduced. Further, since the metal can be connected to ceramic while hardening the metal, man-hour can be reduced markedly.

Claims

1. A ceramic/metal composite turbine rotor assembly comprising a ceramic turbine rotor and a metal shaft which have been heat-connected to each other, wherein the ceramic turbine rotor has a coefficient of thermal expansion of about 8.0×

10^-6 /°

C. or less and the metal shaft is martensite stainless steel or martensite heat-resistant steel having a Rockwell hardness HRC of at least 40 which has been quench hardened through martensite transformation in a gas or vacuum subsequent to heat-connecting at a temperature higher than the quench hardening temperature of the steel which is at least 800°

C.

2. The turbine rotor assembly as set forth in claim 1, wherein said heat-connection is by brazing, shrinkage fit or both.

3. The turbine rotor assembly as set forth in claim 2, wherein the shrinkage fit comprises a connecting portion of the ceramic turbine rotor enclosed by a corresponding connecting portion of the metal shaft.

4. The turbine rotor assembly as set forth in claim 1, wherein said metal shaft has expanded at least 0.02% through the martensite transformation during cooling subsequent to the heat-connection.

5. The turbine rotor assembly as set forth in claim 1, wherein the heat-connection is butt-brazing.

6. The turbine rotor assembly as set forth in claim 1, wherein said metal shaft has expanded at least 0.1% through the martensite transformation during a course of cooling subsequent to the heat-connection.

7. The turbine rotor assembly as set forth in claim 1, wherein said metal shaft has a Rockwell hardness HRC of at least 45.

8. The turbine rotor assembly as set forth in claim 7, wherein said metal shaft has a Rockwell hardness HRC of at least 50.

9. The turbine rotor assembly as set forth in claim 1, wherein said ceramic turbine rotor has a coefficient of thermal expansion of nor more than about 4.6×

10^-6 /°

C.

10. The turbine rotor assembly as set forth in claim 1, wherein said ceramic turbine rotor is one selected from the group consisting of sintered bodies of silicon nitride, silicon carbide, alumina and mixtures thereof.