CeO2, ZrO2, and a series of CexZr1-xO2 catalysts with 1 wt% Pd were exposed to fixed exposures of SO2 under oxidizing environments and then characterized by FTIR, pulse-reactor studies with CO and O2, and temperature-programmed desorption (TPD). For exposures above 473 K, sulfates were formed on all of the materials; however, the results are consistent with the formation of bulk sulfates on CeO...

The aim of the present study was to evaluate the antibiofilm activity against Enterococcus faecalis, compressive strength. and radiopacity of Portland cement (PC) added to zirconium oxide (ZrO2), as radiopacifier, with or without nanoparticulated zinc oxide (ZnO). The following experimental materials were evaluated: PC, PC + ZrO2, PC + ZrO2 + ZnO (5%), and PC + ZrO2 + ZnO (10%). Antibiofilm act...

Mineral trioxide aggregate (MTA) and Portland cement (PC) are calcium silicate cements. They have similar physicochemical, mechanical and biological properties. The addition of zirconium oxide (ZrO2) to PC provides radiopacity. Silver nanoparticles (AgNPs) may improve some properties of cements. The aim of this study was to evaluate the effect of AgNPs on physicochemical/mechanical properties a...

The partial oxidation and CO2 reforming of methane were studied on Pt/Al2O3, Pt/ZrO2, and Pt/ Ce–ZrO2 catalysts. The reducibility and the oxygen transfer capacity were evaluated by oxygen storage capacity (OSC). The effect of the support on the cleaning mechanism of the catalyst surface was investigated by the sequence of CH4/O2 and CH4/CO2 pulses. The Pt/Ce–ZrO2 catalyst showed the highest sta...

Structure-activity relationships of a nanostructured Cu/ZrO2 catalyst for the steam reforming of methanol (MSR) were investigated under reaction conditions by in situ X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) combined with on-line mass spectrometry (MS). Temperature programmed activation by reduction in hydrogen or by reduction in a mixture of methanol and water (feed) was...

Zirconium Oxide (ZrO2) is an interesting material in optical filters, gas sensors and protective coatings owing to their outstanding optical, chemical, thermal and mechanical properties. Zirconium Oxide thin films were deposited on glass substrates by sol gel dip coating method, using alcoholic solutions. The dipping solution was prepared from Zirconium OxychlorideOctahydrate and Isopropanol wi...

Throughout the Earth’s history, mass transport involved fluids. In order to address the circumstances under which Zr may have been transported in this manner, its solubility behavior in aqueous fluid with and without NaOH and SiO2 in equilibrium with crystalline ZrO2 was determined from 550 to 950 °C and 60 to 1200 MPa. The measurements were carried out in situ while the samples were at the tem...

nanocomposite of zro2/zno was prepared under ultrasonic irradiation by sol gel process from directly mixing zirconium and zinc gels. the mixture was placed under ultrasonic irradiation for 2 hours. after the aging time and filtration of the reaction mixture, the filtrated composite gel was calcinated at 500 °c for 3h in furnace. the precursor gels of zirconium and zinc were prepared from dissol...

The free energy of formation of zircon (ZrSiO4) from its oxides was determined between 1100 and 1300 K by an electrochemical method, in which values of μO2 deÞ ned by the two assemblages Fe2SiO4-Fe-SiO2 (fayalite-iron-quartz) and Fe2SiO4-Fe-ZrO2-ZrSiO4 were each measured using oxygen concentration cells with calcia-stabilized zirconia solid electrolytes. The difference in μO2 between these two ...

Transformation plasticity in ZrO2, which is responsible for the high strength and high toughness of advanced ZrO2-based ceramics, is reviewed. The tetragonal ~ monoclinic martensitic transformation is of prime importance, but its successful exploitation requires a good deal of microstructural control. Under certain conditions, the transformation can be reversible, autocatalytic, and thermoelast...