Despite the well-known beneficial effect of reactive element dopants on improving oxidation resistance alumina-forming alloys, many open questions remain, including migration and segregation elements at oxide/alloy interface, a key zone in controlling global kinetics interface adhesion. Herein, we elucidate atomic processes governing interfacial dynamics hafnium with γ-Al2O3 θ-Al2O3, two domina...

The oxidative dehydrogenation (ODH) of propane was investigated on vanadia dispersed on alumina containing a nominal polymolybdate monolayer (4.8 Mo/nm2). Dehydrogenation rates and selectivities on these catalysts were compared with those on vanadia domains dispersed on alumina. At a given vanadia surface density, ODH reaction rates per gram of catalyst were about 1.5–2 times greater on MoOx -c...

in this research, a new technetium-99m generator has been developed with addition of cerium oxide to alumina column.  the adsorption behaviors of 99mo in the form of molybdate and 99mtc in the form of pertechnetate on ceo2/al2o3 was investigated and showed that the adsorption capacity of molybdate on this generator is higher than usual generator using al2o3. ceric ions were selected as an addit...

Alumina-supported Pt is one of the major industrial catalysts for light alkane dehydrogenation. This catalyst loses activity during reaction, with coke formation often considered as the reason for deactivation. As we show in this study, the amount and nature of carbon deposits do not directly correlate with the loss of activity. Rather, it is the transformation of subnanometer Pt species into l...

In this study, γ-Al2O3 particles were dispersed in p-type Bi0.4Sb1.6Te3 through mechanical alloying to form γ-Al2O3/Bi0.4Sb1.6Te3 composite powders. The composite powders were consolidated using vacuum hot pressing to produce nanoand microstructured composites. Thermoelectric (TE) measurements indicated that adding an optimal amount of γ-Al2O3 nanoparticles improves the TE performance of the fa...

The paper reports a process for synthesis of γ-alumina from kaolin. Kaolin was transformed to meta-kaolin by calcination at 800 ̊C for 2h. γ-alumina powder was synthesized through extracting alumina from metakaolin via H2SO4 and meta-kaolin reactions and consequently precipitation in ethanol, which led to form the aluminum sulfate. The precipitated aluminum sulfate was dried and calcined at 900 ̊...

Laser-induced fluorescence measurements of OH radical concentration are performed in the post-flame gaseous region of a stoichiometric H2=O2 mixture combusting at 20 Torr. The measurements are taken near surfaces of three different materials [a-alumina (Al2O3), quartz (SiO2), and platinum (Pt) on alumina] at different surface temperatures (from 700 to 1100 K). A comparative analysis of some of ...

Alumina-titania coatings are widely used in industry for wear, abrasion or corrosion protection components. Such layers are commonly deposited by atmospheric plasma spraying (APS) using powder as feedstock. In this study, both Al2O3 and Al2O3-13 wt% TiO2 coatings were deposited on austenitic stainless steel coupons by suspension plasma spraying (SPS). Two commercial suspensions of nanosized Al2...

Hydrocarbon (HC) assisted selective catalytic reduction (SCR) is an appealing technology for NOx reduction in oxygen excess. In particular, a catalyst formulation with silver supported on alumina (Ag/Al2O3) has been measured to have high activity for this reaction [1,2]. Although numerous experimental studies have clarified issues concerning the Ag/Al2O3 catalyst, the nature of the active phase...

We have studied an alumina/zirconia interface using the all-electron projector augmented wave formalism within density functional theory. We present the electronic, structural, and energetic properties of the ZrO2(001)/a-Al2O3(11̄02) interface as well as of the free a-Al2O3(11̄02) and ZrO2(001) surfaces. We find that the generalized gradient correction significantly lowers the oxide surface energ...