Method for Bonding a Titanium Based Mesh to a Titanium Based Substrate
A method for metallurigically bonding a metal wire mesh to a metal substrate which allows the use of a fragile open weave mesh and/or a thin wall substrate. A thin nickel based layer is placed between a titanium based substrate and a titanium based wire mesh. The mesh and substrate are lightly clamped in intimate contact against the nickel interlayer therebetween, e.g., by wire wrapping. The sandwich, or assembly, (i.e., substrate, interlayer, mesh) is then heated to a temperature, below the melting point of titanium and nickel but sufficient to form a eutectic titanium-nickel alloy (e.g. , Ti 2 Ni).
1 . A method of bonding a metal mesh to a metal substrate comprising:
placing a layer of nickel based material on the surface of a titanium based substrate;
placing a titanium based mesh structure on said layer of nickel based material;
forming an assembly by holding said substrate surface and said mesh structure in intimate contact with said layer; and
heating said assembly to a temperature below the melting point of titanium and nickel but sufficient to form a titanium nickel alloy bonding said mesh structure and said substrate.
2 . The method of claim 1 wherein said step of heating comprises heating said assembly to a eutectic temperature.
3 . The method of claim 2 wherein said step of heating comprises heating said assembly to a temperature of about 1035° C.
4 . The method of claim 1 wherein said step of heating comprises heating said assembly in a vacuum to a eutectic temperature of about 1035° C., over a period on the order of 60 minutes and dwelling at said eutectic temperature for a period on the order of 10 minutes.
5 . The method of claim 4 further including
cooling said assembly to an ambient temperature while in said vacuum over a period on the order of 2-3 hours.
6 . The method of claim 1 wherein said mesh structure is comprised of titanium based wire forming mesh openings on the order of 50 to 200 microns,
7 . The method of claim 1 wherein said step of forming said assembly includes holding said substrate and said mesh structure in intimate contact with a force insufficient to significantly distort said mesh structure or substrate.
8 . A medical device suitable for implantation in a patient's body, said device comprising:
a substrate defining a titanium bonding surface;
a porous pad comprised of titanium wires; and
a titanium nickel alloy bonding a plurality of said titanium wires to said titanium bonding surface.
9 . The device of claim 8 wherein said alloy is diffused into said bonding surface.
10 . The device of claim 8 wherein said alloy comprises a eutectic of titanium and nickel.