LASER Powder Deposition of Titanium - Tantalum Alloy Structured Interfaces for Use in Orthopedic Devices

摘要

Tantalum has been demonstrated to have increased biocompatibility and osseointegrative properties compared to other more commonly used orthopedic grade alloys. Despite the biocompatibility of pure tantalum, there are several drawbacks to the use of it as a bulk biomaterial: low yield strength, high modulus of elasticity, high density, and high material and processing costs that make it prohibitively expensive. The use of tantalum-titanium alloys for the manufacture of orthopedic implants, in theory, could produce a device with a desired strength and low modulus of elasticity, while retaining much of the biocompatibility of tantalum. Bonding a functional tantalum coating to a titanium orthopedic device is inherently difficult because of the small difference between the melting temperature of tantalum, 3017℃, and the boiling point of titanium, 3287℃. LASER Powder Deposition (LPD) is a fusion operation using an Nd:YAG laser piped through a 10μm optical fiber to melt a small volume of substrate into which metal powder is sprayed achieving high temperature with a high solidification rate. LPD of Ti-Ta onto a Ti-6A1-4V substrate produced a structured coating with a pore size in the optimal 350 - 500 μm range. Cell culturing of LPD produced sample coatings showed the rate of cell growth increased as the tantalum fraction of the deposition increased, indicating Ti-Ta LPD surfaces are capable of increased the osseointegrative properties of orthopedic implants.