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Monday, September 24, 2007 - 1:40 PM

Alloy Metal Powders for Medical Applications

P. A. Davies, M. A. Kearns, Sandvik Osprey Ltd, Neath, United Kingdom; H. Holmberg, C. Haraldsson, Sandvik Materials Technology, Sandviken, Sweden

Powder metallurgy offers a number of advantages in the fabrication of high quality, high value medical components. These include refined microstructures with isotropic properties and near-net shape manufacture with high materials utilization. This is important, not only because it avoids the need for machining of hard materials but is also increasingly critical as raw materials costs continue to rise. This paper reviews the development of gas atomized alloy powders for fabrication of medical components by a variety of established and emerging processes. Examples are drawn from cobalt alloy powders used in metal injection molding (MIM) of orthodontic brackets and in vivo implants and from MIM of stainless steel powders for medical instruments. The microstructures and properties achievable in the Co-Cr family of alloys are presented and discussed. The advantages of MIM compared with conventional manufacturing routes are described with reference to general case studies. Other rapid manufacturing technologies that utilize alloy metal powders are also reviewed including Laser and Electron Beam techniques for producing complex and porous structures.

Summary: Sandvik Osprey Ltd has developed a wide range of specialist alloy powders for use in medical applications. Powders are converted using near net shape technologies such as MIM, laser rapid prototyping and hot isostatic pressing. This paper highlights the advantages of powder metallurgical routes for fabrication of high quality, high value medical components. The impact of powder size is discussed in terms of micro structural cleanliness and mechanical properties. Benefits of net shape technology are examined with reference to case studies in terms of fabrication and raw materials costs. Examples are drawn from cobalt alloy powders used in metal injection molding (MIM) of orthodontic products and in vivo implants and from MIM of stainless steel powders for medical instruments. Other rapid manufacturing technologies that utilize alloy metal powders are also reviewed including Laser and Electron Beam techniques for producing complex and porous structures.