Joining of rough carbon-carbon composites with high joint strength

• US 5,972,157 A
• Filed: 08/20/1996
• Issued: 10/26/1999
• Est. Priority Date: 11/20/1995
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Xue, Liang An, Narasimhan, Dave
• Primary Examiner(s): Nguyen, Nam
• Assistant Examiner(s): VerSteeg, Steven H.
• Application Number:
  US08/699,751
• Time in Patent Office: 1,162 Days
• Field of Search: 156/73.5, 156/182, 156/276, 156/285, 156/89, 156/89.11-19, 156/89.21-28, 228/121, 403/271
• US Class Current: 156/285
• CPC Class Codes: C04B 2237/083 Carbide interlayers, e.g. silicon carbide interlayers
• CPC Class Codes: C04B 2237/122 based on refractory metals
• CPC Class Codes: C04B 2237/363 Carbon
• CPC Class Codes: C04B 2237/60 Forming at the joining interface or in the joining layer specific reaction phases or zones, e.g. diffusion of reactive species from the interlayer to the substrate or from a substrate to the joining interface, carbide forming at the joining interface
• CPC Class Codes: C04B 2237/704 of one or more of the ceramic layers or articles
• CPC Class Codes: C04B 2237/708 of one or more of the interlayers
• 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 2237/86 Joining of two substrates at their largest surfaces, one surface being complete joined and covered, the other surface not, e.g. a small plate joined at it's largest surface on top of a larger plate
• CPC Class Codes: C04B 37/005 consisting of glass or ceramic material
• CPC Class Codes: C04B 37/006 consisting of metals or metal salts

Abstract

Carbon--carbon composite parts are joined with minimum surface preparation. A reactive-bonding joint interlayer having thickness greater than 1 mil is formed of fine particles of carbide-forming metallic ingredients and carbon. The joint interlayer is sandwiched between the two carbon--carbon parts to be joined and the assembly is heated under a compressive pressure to a temperature sufficient to complete the bonding reaction. No special surface preparation is required for the carbon--carbon parts due to the nature of the reactive-bonding. The mechanical properties of the joint are assured by selecting the metal-carbon ingredients so that thermal expansion mismatch is minimized. Shear strength exhibited by the resulting joints is greater than the interlaminar shear strength of the carbon--carbon composite material.

Claims

1. A reactive-bonding method for joining two carbon--carbon composite parts, each carbon--carbon part having at least one faying area, comprising the steps of:

a. preparing a reactive-bonding layer having a thickness ranging from about 25 to 2500 micrometers and a dimension matching the faying area of the carbon--carbon parts to be joined, said reactive-bonding layer being comprised of a mixture of fine particle-sized, carbide forming metallic ingredients, and carbon, and having a composition that is metal rich;

b. assembling said carbon--carbon parts and said reactive-bonding layer to form a setup in which the reactive-bonding layer forms a joint interlayer between the parts;

c. heating said setup under a compressive pressure in either a vacuum or an inert gas atmosphere for a time and at a temperature sufficient to complete a bonding reaction to form a compound selected from the group consisting of borides, carbides, silicides and nitrides and which compound is produced within said joint interlayer and between said joint interlayer and said carbon--carbon composite parts, forming a bond between said joint interlayer and between said carbon--carbon composite parts that is non-porous, wherein said metallic ingredients of said reactive-bonding layer have melting points, and said temperature of said heating of said setup can be reduced to a temperature that is less than one-half the melting point of the metallic ingredients.

2. A method as recited by claim 1, wherein the metallic ingredients of the reactive-bonding layer comprise at least one element selected from the group consisting of:

W, Ti, Si, Ta, Nb, Zr, Hf, V, Cr, and Mo.

3. A method as recited by claim 1, wherein the reactive-bonding layer additionally comprises a filler material composed of at least one refractory compound selected from the group consisting of:

borides, carbides, silicides, and nitrides.

4. A method as recited by claim 1, wherein said compressive pressure applied to said setup ranges from about 0.1 to 50 megapascals.

5. A method as recited by claim 1, whereby, after being joined, said carbon--carbon composite parts form a carbon--carbon joint having a joint shear strength greater than the interlaminar shear strength of the carbon--carbon parts.

6. The method of claim 1, whereby, after being joined, said carbon--carbon composite parts form a carbon--carbon joint having a thickness greater than 25 micrometers and said joint interlayer has a thermal expansion matched to the carbon--carbon parts.

7. A reactive-bonding method for joining two carbon--carbon composite parts, each carbon--carbon part having at least one faying area, consisting of the steps of:

a. preparing a reactive-bonding layer having a thickness ranging from about 25 to 2500 micrometers and a dimension matching the faying area of the carbon--carbon parts to be joined, said reactive-bonding layer being comprised of a mixture of fine particle-sized, carbide forming metallic ingredients, and carbon, and having a composition that is metal rich;

b. assembling said carbon--carbon parts and said reactive-bonding layer to form a setup in which the reactive-bonding layer forms a joint interlayer between the parts;

c. heating said setup under a compressive pressure in either a vacuum or an inert gas atmosphere for a time and at a temperature sufficient to complete a bonding reaction to form a compound selected from the group consisting of borides, carbides, silicides and nitrides and which compound is produced within said joint interlayer and between said joint interlayer and said carbon--carbon composite parts, forming a bond between said joint interlayer and between said carbon--carbon composite parts that is non-porous, wherein said metallic ingredients of said reactive-bonding layer have melting points, and said temperature of said heating of said setup can be reduced to a temperature that is less than one-half the melting point of the metallic ingredients.

8. A method as recited by claim 7, wherein the metallic ingredients of the reactive-bonding layer comprise at least one element selected from the group consisting of:

W, Ti, Si, Ta, Nb, Zr, Hf, V, Cr, and Mo.

9. A method as recited by claim 7, wherein the reactive-bonding layer additionally comprises a filler material composed of at least one refractory compound selected from the group consisting of:

borides, carbides, silicides, and nitrides.

10. A method as recited by claim 7, wherein said compressive pressure applied to said setup ranges from about 0.1 to 50 megapascals.

11. A method as recited by claim 7, whereby, after being joined, said carbon--carbon composite parts form a carbon--carbon joint having a joint shear strength greater than the interlaminar shear strength of the carbon--carbon parts.

12. The method of claim 7, whereby, after being joined, said carbon--carbon composite parts form a carbon--carbon joint having a thickness greater than 25 micrometers and said joint interlayer has a thermal expansion matched to the carbon--carbon parts.