Method of bonding titanium to stainless steel

• US 8,091,765 B2
• Filed: 01/20/2006
• Issued: 01/10/2012
• Est. Priority Date: 04/07/2004
• Status: Active Grant

• Current Assignee: Alfred E. Mann Foundation For Scientific Research
• Original Assignee: Alfred E. Mann Foundation For Scientific Research
• Inventors: Jiang, Guangqiang, Antalfy, Atilla
• Primary Examiner(s): Ward, Jessica L
• Assistant Examiner(s): HA, STEVEN S
• Application Number:
  US11/336,596
• Publication Number:
  US 20060113357A1
• Time in Patent Office: 2,181 Days
• Field of Search: 228/203, 228/245, 228/246, 228/248.1, 228/253, 228/56.3, 428/661, 428/648, 428/680, 428/685
• US Class Current: 228/203
• CPC Class Codes: A61N 1/372 Arrangements in connection with the implantation of stimulators
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections
• CPC Class Codes: B23K 20/023 Thermo-compression bonding
• CPC Class Codes: B23K 2103/24 Ferrous alloys and titanium or alloys thereof
• CPC Class Codes: B23K 35/004 at least one of the workpieces being of a metal of the iron group
• CPC Class Codes: B23K 35/005 at least one of the workpieces being of a refractory metal
• CPC Class Codes: B23K 35/0238 layered
• CPC Class Codes: Y10T 29/49993 Filling of opening
• CPC Class Codes: Y10T 428/12069 Plural nonparticulate metal components
• CPC Class Codes: Y10T 428/12806 Refractory [Group IVB, VB, or VIB] metal-base component
• CPC Class Codes: Y10T 428/12937 Co- or Ni-base component next to Fe-base component
• CPC Class Codes: Y10T 428/12979 Containing more than 10% nonferrous elements [e.g., high alloy, stainless]

Abstract

A method of bonding a stainless steel part to a titanium part by heating a component assembly comprised of the titanium part, the stainless steel part, and a laminated titanium-nickel filler material placed between the two parts and heated at a temperature that is less than the melting point of either the stainless steel part or the titanium part. The component assembly is held in intimate contact at temperature in a non-reactive atmosphere for a sufficient time to develop a hermetic and strong bond between the stainless steel part and the titanium part. The bonded component assembly is optionally treated with acid to remove any residual free nickel and nickel salts, to assure a biocompatible component assembly, if implanted in living tissue.

Claims

1. A method of making a living tissue implantable component assembly, comprising the steps of:

selecting a biocompatible 316L stainless steel part;

selecting a biocompatible titanium part that is comprised of Ti-6Al-4V;

selecting a laminated filler material that is less than about 0.010 inches thick that is comprised of a 22% to 98% nickel portion and a remaining titanium portion, said laminated filler material comprising at least two nickel layers surrounding at least one titanium layer,

selecting said laminated filler material having a melting point that is lower than the melting point of said titanium part and said stainless steel part;

positioning said filler material between said stainless steel part and said titanium part;

placing the assembly in a non-reactive atmosphere;

applying a force to said stainless steel part and said titanium part to place said filler material in compression, thereby creating intimate contact between said stainless steel part, said filler material, and said titanium part;

heating the assembly to a temperature between said melting point of said laminated filler material and said melting point of said titanium part;

holding the assembly at said bonding temperature for a predetermined time to form a bond between said stainless steel part and said titanium part;

cooling the assembly; and

implanting the component assembly in a human body.

2. The method of claim 1 wherein said step of applying a force creates compression between about 5 and 50 psi.

3. The method of claim 1 wherein said step of applying a force creates compression between about 5 and 7 psi.

4. The method of claim 1 further comprising the step of forming said filler material from metallic particulate.

5. The method of claim 1 further comprising the step of placing the assembly in a non-reactive atmosphere is placing in a vacuum less than 10⁻

5 Torr.

6. The method of claim 1 further comprising the step of placing the assembly in a non-reactive atmosphere is placing in argon gas.

7. The method of claim 1 wherein said bonding temperature is between approximately 940°

and 1260°

C.

8. The method of claim 1 wherein said predetermined time is between approximately 5 and 60 minutes.

9. The method of claim 1 additionally comprising the step of cleaning said component assembly after bonding to remove elemental nickel and nickel salts.

10. The method of claim 9 additionally comprising the step of cleaning said component assembly after bonding by placing it in an acid bath.

11. A method of making a living tissue implantable component assembly, comprising the steps of:

selecting a biocompatible stainless steel part from the group consisting of corrosion resistant stainless steels;

selecting a biocompatible titanium part comprised of Ti-6Al-4V;

positioning a laminated filler material between said stainless steel part and said titanium part;

applying a force to said stainless steel part and said titanium part to place said filler material in compression between 5 and 7 psi, thereby forming said component assembly;

placing said component assembly in a non-reactive atmosphere;

heating said component assembly to between approximately 940° and

1260°

C. for between approximately 5 and 60 minutes;

cooling said component assembly;

cleaning said component assembly after cooling to remove elemental nickel and nickel salts; and

implanting the component assembly into a human body.