In this study a coaxial line was used to connect a microwave-frequency Network Analyzer and a base moving sample holder for dielectric characterization of ferroelectric materials in the microwave range. The main innovation of the technique is the introduction of a special sample holder that eliminates the air gap effect by pressing sample using a fine pressure system control. The device was pre...

Polyurethane-based micro- and nano-hybrid composites were produced with controlled porosity to be used as obturation materials. In addition to hydroxyapatite (HAp) micro-particles in the composites, two different ceramics particle types were also added: alumina micro-particles and silica nano-particles. Particles of different sizes provide the materials with improved mechanical properties: the ...

The notion of replicating the unique fracture resistance of natural composites in synthetic materials has generated much interest but has yielded few real technological advances. Here we demonstrate how using ice-templated structures, the concept of hierarchical design can be applied to conventional compounds such as alumina and poly(methyl methacrylate) (PMMA) to make bulk hybrid materials tha...

Production of transparent ceramics has become a topic of resurgent interest in recent years, with its promise of near-net shaping appealing to applications ranging from biomedicine to solar energy. However, the mechanisms governing ceramic transparency, translucency, and opaqueness are not entirely understood. Models of both grain boundary and pore scattering have been proposed, but too often w...

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...

Thin compressive layers within a laminar ceramic arrest large cracks (surface and internal) and produce a threshold strength. This phenomenon increases the damage tolerance of ceramics and will allow engineers to design reliable ceramic components for structural applications. The stress intensity factor derived for a crack sandwiched between two compressive layers suggests that the threshold st...

A rapidly developing area of ceramic science and technology involves research on the interaction between implanted biomaterials human body. Over past half century, use bioceramics has revolutionized surgical treatment various diseases that primarily affect bone, thus contributing to significantly improving quality life rehabilitated patients. Calcium phosphates, bioactive glasses glass-ceramics...

A novel and aqueous gel-casting process has been successfully developed to fabricate porous MgAl₂O₄ ceramics by using hydratable alumina and MgO powders as raw materials and deionized water as hydration agent. The effects of different amounts of deionized water on the hydration properties, apparent porosity, bulk density, microstructure, pore size distribution and compressive strength of the sa...

Glass-ceramic materials were developed from gabbro including MgO and Al2O3 additives. Heat treatments for phase transformation from glassy matrix to glass-ceramic were carried out at 1000 ◦C for 3 h. X-ray di raction studies conducted on the glass-ceramic samples revealed that the phases formed in the glass-ceramics were cordierite, anorthite, diopsitic augite, forsterite and andesine. Glass an...