Method for attaching a porous metal layer to a metal substrate

Abstract

A method for attaching a porous metal layer to a dense metal substrate, wherein the method is particularly useful in forming orthopedic implants such as femoral knee components or acetabular cups. The method, in one embodiment thereof, comprises providing a structured porous layer; providing a dense metal substrate; providing a binding mixture; applying the binding mixture to the exterior of the substrate; placing the porous layer against the substrate such that the binding mixture is disposed there between forming an assembly; and heat treating the assembly to metallurgically bond the porous layer to the substrate.

Description

RELATED APPLICATION [0001] This application is a divisional of co-pending U.S. patent application Ser. No. 10 / 455,846, filed on Jun. 6, 2003 which is a non-provisional of U.S. Provisional Patent Application Ser. No. 60 / 389,615, filed on Jun. 18, 2002, the disclosure of which is hereby explicitly incorporated by reference herein.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to orthopedic implants of the type having a porous surface into which bone tissue can grow or bone cement can enter and, more particularly, to a method of bonding a porous metal structure, such as porous titanium or porous tantalum onto a metal substrate preferably comprising a titanium-based or cobalt-based alloy. [0004] 2. Description of the Related Art [0005] Orthopedic implant devices commonly include a porous structure of desired thickness, generally 0.5 to 5.0 mm, on the bone contacting surface of the implant to promote bone growth there through and to enha...

AI Technical Summary

Benefits of technology

The present invention provides a method for bonding a porous metal layer to titanium or cobalt alloy surfaces using a sintering or diffusion bonding process. The method involves applying a binding mixture to the substrate or porous metal, placing them together, and subjecting them to heat and / or pressure to create a strong and corrosion-resistant bond. This method can be used to create orthopedic implants with enhanced bond strength and corrosion resistance. The technical effects of this invention include the ability to bond a porous metal layer to a variety of metal substrates using a single bonding process that protects the metallurgical properties of the component alloys.

Problems solved by technology

In spite of the value of using a porous layer in orthopedic implants, bonding porous metal to a metal substrate such as cobalt alloy or titanium alloy has been difficult, especially in the case of HEDROCEL.

The reason for this difficulty is that metallurgically bonding two components generally requires a large amount of contact between the surfaces at which the bond is desired.

The porosity of HEDROCEL results in sparse contact with an opposing metal substrate, thereby making sintering or diffusion bonding difficult.

Moreover, this porosity also makes it difficult to maintain the narrow dimensioning tolerances for machined HEDROCEL components.

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