No CrossRef data available.
Article contents
Structure and Mechanical Properties of Functionally-Graded Nanostructured Metalloceramic Coatings
Published online by Cambridge University Press: 10 February 2011
Abstract
A functionally graded nanocrystalline metalloceramic coating on cobalt-chrome alloy was investigated using thin film x-ray diffraction (XRD), cross-sectional transmission electron microscopy (TEM), nanoindentation, and scratch adhesion testing. The gradual transition in bonding from metallic (Cr/CrTi) near the interface to predominantly covalent (CrTiN) near the surface provides a combination of high toughness and high surface hardness. XRD analysis of the (CrTiN) coating suggests a cubic sodium chloride type phase structure with lattice parameter a = 4.2169±0.0035 Å. The surface layer structure is described as a tertiary Ti-N-Cr disordered solid solution that is predominantly cubic TiN, but with some Cr atoms substituted for Ti. TEM shows a transition from equiaxed 20-40 nm-sized grains at the surface to larger, elongated columnar grains below the surface. Nanoindentation measurements of the coating result in a hardness of 27 GPa and Young's modulus of 320 GPa. In addition, the high plasticity of 55% observed for this coating represents an increase in toughness over other ceramic coatings having similar hardness. The unique, functionally graded, smooth nanocrystalline metalloceramic coating structure provides an opportunity to reduce wear and increase longevity of total hip joint replacements.
- Type
- Research Article
- Information
- Copyright
- Copyright © Materials Research Society 2002