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Sopyan I.,International Islamic University Malaysia | Ramesh S.,University of Malaya | Nawawi N.A.,International Islamic University Malaysia | Tampieri A.,Institute of Science and Technology for Ceramics ISTEC | Sprio S.,Institute of Science and Technology for Ceramics ISTEC
Ceramics International | Year: 2011

We have investigated the effect of manganese (Mn) doping on properties of nanosized biphasic calcium phosphate powders and their dense bodies. Manganese levels of 0.6, 1.3, 1.9, 4.3, 7.0 and 11.9 at.% were successfully incorporated into biphasic calcium phosphate via a sol-gel route. The prepared powders were calcined at temperatures of 500-1200 °C. The X-ray diffraction analysis revealed that a mix phase comprising of hydroxyapatite and β-tricalcium phosphate were present, however the content of each phases in the structure was affected by the Mn content. The studies found that the largest portion of β-tricalcium phosphate was detected at 4.3 at.% Mn doping. The incorporation of Mn has also greatly increased the crystallinity of the biphasic calcium phosphate powder due to progressive densification of particles. Characterization on their sintered dense bodies showed that manganese concentration affected the physical properties of the dense bodies. The highest density was found for 4.3 at.% Mn doped biphasic calcium phosphate sintered at 1300 °C. © 2011 Elsevier Ltd and Techna Group S.r.l. Source


Cernea M.,National Institute of Materials Physics Bucharest | Galizia P.,Institute of Science and Technology for Ceramics ISTEC | Ciuchi I.,Institute of Science and Technology for Ceramics ISTEC | Ciuchi I.,Al. I. Cuza University | And 4 more authors.
Journal of Alloys and Compounds | Year: 2016

Cobalt ferrite (CoFe2O4) has been successfully synthesized by sol-gel technique. Pellets were prepared by spark plasma sintering technique (SPS) from CoFe2O4 sol-gel derived powder. The rapid sintering of CoFe2O4 pellet by SPS at 950 °C, leads to a dense ceramic (97%ρtheoretic) with average crystallite size of 71 nm. As revealed by X-ray diffraction and Mössbauer measurements, the obtained powder and SPS pellets are spinel ferrite with a cubic symmetry. Complex dielectric investigation performed on CoFe2O4 ceramic reveals multiple relaxation mechanisms while the magnetic measurements indicated a saturation magnetization value of ∼83 A m2/kg at room temperature, which make them useful for applications in microwave domain. © 2015 Elsevier B.V. All rights reserved. Source


Rizzo G.,Institute for Agricultural and Earthmoving Machines IMAMOTER | Massarotti G.P.,Institute for Agricultural and Earthmoving Machines IMAMOTER | Bonanno A.,Institute for Agricultural and Earthmoving Machines IMAMOTER | Paoluzzi R.,Institute for Agricultural and Earthmoving Machines IMAMOTER | And 5 more authors.
International Journal of Fluid Power | Year: 2015

This paper shows the experimental results obtained using a nanocoating (developed by ISTEC-C.N.R.) applied to the slippers of an axial piston pump to reduce the friction losses in order to improve the pump overall efficiency map. It is well known that the mechanical power losses in a hydraulic pump come from the friction between parts in relative motion. The need to provide, especially at low rotational speed, hydrodynamic lift causes power losses in terms of volumetric and mechanical efficiency, due to the contrasting need to increase leakage to provide lubrication and to keep a minimum clearance in meatus to limit the volumetric losses. The application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers, but the potential of structured coatings at nanoscale, with superhydrophobic and oleophobic characteristics, has never been exploited. Using a dedicated test rig developed at IMAMOTER-C.N.R., able to ensure hydrostatic working condition during the mutual rotation between the slippers and the swash plate, the functional performance of the nanocoated slippers' surface have been studied. In the first part of the paper, the functionalization method is presented; in the second part, a comparison between the experimental performances of coated and uncoated surfaces is showed. © 2015 Taylor & Francis. Source

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