Learn More
Zirconia has been used as an orthopaedic material since 1985 and is increasingly used in dental applications. One major concern with the use of zirconia is the significant loss in mechanical properties through hydrothermal degradation, with the uncontrolled transformation of tetragonal to monoclinic (t→m) zirconia. We report on the addition of alumina and(More)
The performance of total hip-joint replacements depends strongly on the state of lubrication in vivo. In order to test candidate prosthetic materials, in vitro wear testing requires a lubricant that behaves in the same manner as synovial fluid. The current study investigated three lubricants and looked in detail at the lubrication conditions and the(More)
CaCu3Ti4O12 (CCTO) is a cubic perovskite phase and sintered ceramics exhibit high permittivity at room temperature. Electron energy-loss spectroscopy (EELS) and energy dispersive X-ray spectrometry (EDS) data have been collected from samples of CCTO to relate the observed electrical properties to the microstructure and chemistry on the nanoscale. CCTO(More)
Alumina hip replacement prostheses have been analyzed following in vitro simulated microseparation. The worn surfaces of the alumina acetabular cup and femoral head were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM) which identified four different wear zones. Focused ion beam (FIB) cross-sectioning was used to(More)
It is often the dynamic microstructural changes induced by tribological contact that determine whether or not a material exhibits good wear resistance. It is well known that the mechanical properties of a surface are significantly different from the bulk, an effect amplified by wear induced plastic deformation and electrochemical effects. Despite the(More)
The design of atomic-scale microstructural traps to limit the diffusion of hydrogen is one key strategy in the development of hydrogen-embrittlement-resistant materials. In the case of bearing steels, an effective trapping mechanism may be the incorporation of finely dispersed V-Mo-Nb carbides in a ferrite matrix. First, we charged a ferritic steel with(More)
Zirconia femoral heads retrieved from patients after different implantation periods (up to 13 years) were analysed using vertical scanning interferometry, atomic force microscopy and Raman microspectroscopy. A range of topographical and compositional changes on the surface of the retrievals are reported in this work. The study revealed that changes in(More)
The transformation on heating LiCoMnO4, with a spinel structure, to LiCoMnO3, with a cation-disordered rock salt structure, accompanied by loss of 25% of the oxygen, has been followed using a combination of diffraction, microscopy and spectroscopy techniques. The transformation does not proceed by a topotactic mechanism, even though the spinel and rock salt(More)
This work addresses two major issues relating to Helium Ion Microscopy (HeIM). First we show that HeIM is capable of solving the interpretation difficulties that arise when complex three-dimensional structures are imaged using traditional high lateral resolution techniques which are transmission based, such as scanning transmission electron microscopy(More)
The aim of the present investigation was to determine the orientation dependence of substructure characteristics in an austenitic Fe-30wt%Ni model alloy subjected to hot plane strain compression. Deformation was carried out at a temperature of 950 degrees C using a strain rate of 10 s(-1) to equivalent strain levels of approximately 0.2, 0.4, 0.6 and 0.8.(More)