Alumina-zirconia nano-composites were recently developed as alternative bearing materials for orthopedics. Previous, preliminary reports show that such alumina-zirconia nanocomposites exhibit high crack resistance and low wear rate. In this paper, additional information is given in terms of wear, crack resistance and ageing behaviour: femoral heads are inspected after 7 million cycles of wear t...

During the processing of laminar ceramic, biaxial, residual stresses can arise due to differential thermal contraction between unlike layers. A tensile stress can cause pre-existing flaws to extend across the layer and into the adjacent layers and then tunnel until they meet either another crack or a free surface. A previous analysis has shown that for a given residual stress there is a critica...

The aim of this investigation was to determine the influence of simulated ageing on the tetragonal-to-monoclinic phase transformation and on the flexural strength of a 3Y-TZP ceramic, compared to alumina toughened zirconia (ATZ) and ceria-stabilized zirconia (12Ce-TZP). Standardized disc specimens of each material were hydrothermally aged in steam at 134°C and 3bar for 0, 16, 32, 64 or 128h. Th...

Catalyst layers (4-20 microm) of rhodium (1 wt%) supported on alumina, titania, and ceria-zirconia (Ce(0.5)Zr(0.5)O(2)) were coated on stainless-steel corrugated sheets by dip-coating in very stable colloidal dispersions of nanoparticles in water. Catalytic performances were studied for low-temperature (< or = 500 degrees C) steam reforming of propane at a steam to carbon ratio equal to 3 and l...

We have studied an alumina/zirconia interface using the all-electron projector augmented wave formalism within density functional theory. We present the electronic, structural, and energetic properties of the ZrO2(001)/a-Al2O3(11̄02) interface as well as of the free a-Al2O3(11̄02) and ZrO2(001) surfaces. We find that the generalized gradient correction significantly lowers the oxide surface energ...

The aim of this study was to evaluate the effect of surface roughness on the initial attachment of mouse osteoblast-like cells on ceriastabilized zirconia/alumina nanocomposite (NANOZR) and yttria-stabilized zirconia (3Y-TZP) in comparison to those on pure titanium (Ti) and alumina oxide (AO). Specimens with smooth and rough surfaces were prepared by grinding with diamond paper or by sandblasti...

Catalysts based on zirconia and alumina-supported tungsten oxides (3–18 wt% W) with a small loading of platinum (0.3 Pt) were selected to study the influence W loading, support type, preparation methods hydroisomerization n-dodecane. The alumina- zirconia-supported catalysts show different catalytic properties that play an important role in n-dodecane conversion. Specific surface area acidity a...

Ceramic matrix materials have attracted great attention from researchers and industry due to their material properties. When used in engineering systems, especially aero-engine applications, they can result reduced weight, higher temperature capability, and/or cooling needs, each of which increases efficiency. This is where high-temperature ceramics made considerable progress, ceramic composite...