Highly pure and well-dispersed yttria nanocrystalline powders were synthesized with a modified coprecipitation method that uses mixed ammonium hydroxide-carbonate solution as the precipitant poly acrylic acid (PAA) dispersant. Comparing using same route but without PAA dispersant, PAA-assisted exhibit lower level of agglomeration better sinterability. Sintering trajectories dispersant investiga...

The effect of sintering process parameters on the properties of 3 mol% yttria partially stability zirconia (3Y-PSZ) ceramics has been investigated. The relative density of the sintered pellet rapidly increases from 70.5 to 93.6 % with rose temperature from 1473 to 1573 K. In addition, the relative density only slightly increases from 94.9 to 96.6 %, when rose sintered temperature from 1573 to 1...

Tetragonal Zirconia Polycrystals stabilized with 3% mol. content of yttria (3Y-TZP) has excellent properties in terms of strength and fracture toughness. These properties are mostly imputable to the transformation toughening mechanism, by which the doped metastable tetragonal phase of zirconia transforms to monoclinic under applied stress ahead of a crack. This phenomenon is accompanied by a vo...

The effect of the shell thickness and density on the magnetic properties of composite colloidal particles consisting of a hematite (alpha-Fe(2)O(3)) core and an yttrium oxide (Y(2)O(3)) layer is described. Pure iron oxide colloidal spheres show two clearly different trends of variation of their magnetic susceptibility, chi(m), with temperature. Below T(M) approximately 220 K, chi(m) shows a sli...

Recent developments in solid-oxide fuel cells (SOFC) that electrochemically oxidize hydrocarbon fuels to produce electrical power without first reforming them to H2 are described. First, the operating principles of SOFCs are reviewed, along with a description of state-of-the-art SOFC designs. This is followed by a discussion of the concepts and procedures used in the synthesis of direct-oxidati...

yttria-stabilized zirconia S. Ghosh, D. Teweldebrhan, J. R. Morales, J. E. Garay, and A. A. Balandin Nano-Device Laboratory, Department of Electrical Engineering, University of CaliforniaRiverside, Riverside, California 92521, USA Department of Mechanical Engineering, University of California-Riverside, Riverside, California 92521, USA Materials Science and Engineering Program, University of Ca...

objectives: masking ability of a restorative material plays a role in hiding colored substructures; however, the masking ability of zirconia ceramic (zrc) has not yet been clearly understood in zirconia-based restorations. this study evaluated the effect of three different core materials on masking ability of a zrc. materials and methods: ten zirconia disc samples, 0.5mm in thickness and 10mm i...

objectives : studies on the effect of coloring procedures on the bond strength of zirconia to resin cement are lacking in the literature. this study evaluated the effect of dipping of zirconia ceramic in different liquid color shades on the microtensile bond strength (mtbs) of zirconia ceramic to resin cement. materials and methods: this in vitro study was conducted on 100 microbar specimens di...