STATEMENT OF PROBLEM The whitish color of zirconia (ZrO2) abutments offers favorable esthetics compared with the grayish color of titanium (Ti) abutments. Nonetheless, ZrO2 has greater opacity, making it difficult to achieve natural tooth color. Therefore, lithium disilicate (LaT) abutments have been suggested to replace metal abutments. PURPOSE The purpose of this in vitro study was to evalu...

Although ZrO2 and HfO2 are, for the most part, quite similar chemically, subtle differences in their electronic structures appear to be responsible for differing MO2/Si (M = Zr, Hf) interface stabilities. To shed light on the electronic structure differences between ZrO2 and HfO2, we have conducted joint experimental and theoretical studies. Because molecular electron affinities are a sensitive...

The molecular structures, oxidation states, and reactivity of 3 and 6% CrO3/ZrO2 catalysts prepared by incipient wetness impregnation were examined under different conditions. The in situ Raman spectroscopic studies under dehydrated conditions reveal that the 3 and 6% CrO3/ZrO2 catalysts possess equal amounts of monochromate and polychromate species. Consequently, monolayer coverage on this ZrO...

Graphene-encapsulated nickel nanoclusters are a feasible strategy to inhibit the deactivation of nickel-based catalysts. In this work, graphene-encapsulated catalysts (Ni@C/HZSM-5) were prepared by compression forming process, using pseudo-boehmite, Al2O3, and ZrO2 as binders. The pseudo-boehmite was gradually transformed from amorphous crystalline alumina at high temperatures, which destroyed ...

The amorphous ternary metallic alloy Zr60Al15Ni25 was oxidized in dry oxygen in the temperature range 310 ±C to 410 ±C. Rutherford backscattering (RBS) and cross-sectional transmission electron microscopy (TEM) studies suggest that during this treatment an amorphous layer of zirconium-aluminum-oxide is formed at the surface. Nickel was depleted in the oxide and enriched in the amorphous alloy n...

In situ FT-IR spectroscopy was exploited to study the adsorption of CO2 and CO on commercially available yttria-stabilized ZrO2 (8 mol % Y, YSZ-8), Y2O3, and ZrO2. All three oxides were pretreated at high temperatures (1173 K) in air, which leads to effective dehydroxylation of pure ZrO2. Both Y2O3 and YSZ-8 show a much higher reactivity toward CO and CO2 adsorption than ZrO2 because of more fa...

Preliminary researches were carried out to study the effects of particle size on the wear behavior of a-C coating. The used nanoparticles are W (W-NPs), which have similar bulk hardness with ZrO2 (W: 7.5, ZrO2: 6.5, Mohs scale), but contain larger particles with the diameter of submicron and micron scale (Figure S1). The tribo-tests were performed under the same conditions with the ones used fo...

Integration of luminescent rare earth ions and iridescence into a zirconium oxide photonic material is attractive for the design of new optical devices. The free-standing chiral nematic mesoporous films of ZrO2:Eu(3+) are assembled by a hard-templating approach using nanocrystalline cellulose-templated silica. The ZrO2:Eu(3+) films show tunable optical properties. The chiral nematic structured ...

T he fifth New Energy Technology Symposium was held at the 241st American Chemical Society (ACS) meeting at the Sheraton Park Resort in Anaheim, California on March 27 and 28. The organizer of the symposium, Dr. Jan Marwan of Dr. Marwan Chemie, was unable to chair the meeting due to personal reasons. However, the sessions of the symposium were co-chaired by Dr. Francis Tanzella of SRI Internati...