Highly porous mullite ceramics from engineered alkali activated suspensions

Mullite-alumina functionally gradient ceramics

Cracks free mullite-alumina Functionally Gradient Ceramics (FGC) have been obtained by sequential slip casting of Mullite-alumina slurries with diserent mullite/alumina ratios. These slurries were prepared with 65 % solids content and viscosities rangingpom 10 to 40 mPa.s. 7he presence of cracks perpendicular to the FGC layers have been attributed to residual stresses developed because of the m...

Preparation of High Purity Mullite Ceramics

Highly coupled dielectric behavior of porous ceramics embedding a polymer

We present a theoretical approach to study the dielectric properties of porous ceramics and composite materials and explain the experimentally observed notable influence of the coupling between the components of a saturated porous ceramic on the final behavior of the sample. This model is based on the assumption of a dielectric coupling between the components that modifies the expected averaged...

QUANTITATIVE MICROSTRUCTURAL ANALYSIS AND PIEZOELECTRICITY OF HIGHLY DENSE, SUBMICRON-STRUCTURED NaNbO3 CERAMICS FROM MECHANICALLY ACTIVATED PRECURSORS

We study in this work the processing of NaNbO3 ceramics prepared in a single thermal treatment of highly reactive precursors obtained by mechanical activation of different reagents, aiming to determine optimum conditions for piezoelectric ceramics production. Pressure-less sintering at 1200oC leads to dense ceramics (<5% porosity) with poor mechanical stability, unsuitable for practical uses. D...

AC Microdischarges in Porous Ceramics

Generation of microdischarges inside porous ceramics by AC high voltage has been investigated. Electrical and optical measurements were performed to explore the physical properties of the microdischarges. The effect of pore size, discharge power and gas mixture on the discharge properties and development is described. Introduction Research of various types of non-thermal plasmas generated by el...