Dresden 2006 – scientific programme
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DS: Dünne Schichten
DS 24: Poster presentation
DS 24.62: Poster
Tuesday, March 28, 2006, 15:00–17:30, P2
Mechanical Properties of CoCr Alloys After Nitrogen PlasmaImmersion Ion Implantation — •Inga-Maria Eichentopf, Antje Lehmann, Jürgen W. Gerlach, and Stephan Mändl — Leibniz-Institut für Oberflächenmodifizierung, Leipzig, Germany
Nitrogen implantation at low energies, high fluences and elevated temperatures into CoCr alloys, suitable for medical applications, leads to the formation of modified surface layers by a combination of ion implantation and thermally activated diffusion. After implantation at 25 kV acceleration voltage at temperatures of 300 - 600 ∘C into HS188 and L605, modified surface layers with a thickness between 300 and 5000 nm were found. However, a strong apparent reduction of diffusivity, respective, the activation energy for diffusion was found between 500 and 600 ∘C. A detailed investigation of the phase formation by X-ray diffraction and metallographic cross-section revealed a changing phase composition with CrN and Cr2N dominating at higher temperatures, thus the assumption of a single diffusion process is misleading. The hardness of the surface layer increased from about 300 HV by a factor of 3 – 5.