This paper examines the oxidation behavior of thin specimens cast NiCoCrAlY alloys at 1150 $$^\circ {\rm C}$$ through successive stages, from $${\rm Al}_2{\rm O}_3$$ growth to complete alloy conversion oxide. Five compositions were used, with varying fractions and $$\gamma$$ $$\beta$$ . The time evolution composition during was simulated using DICTRA module Thermo-Calc calculated analytically i...

This report is an evaluation of the selenium removal from agricultural drainage water and synthetic solutions contaminated with high amounts of selenium. Batch and kinetic studies were conducted on the removal of selenium and the effectiveness of various remediation materials was determined. The agricultural drainage water samples were obtained from San Joaquin Valley and provided by Department...

Simultaneous application of colloidal processing and liquidforming additives to alumina resulted in a sintered density of >99% in 1 h at a temperature as low as 1070°C for a commercial high-purity alumina powder at a total dopant level of 2 mol%. The additives were 0.9% CuO + 0.9% TiOz + 0.1% B 2 0 3 + 0.1% MgO. At higher temperatures or after prolonged sintering, the doped alumina ceramic deve...

A comparison has been made of the infrared spectra of alumina with molybdenum oxide alumina in both the oxidized and reduced forms. In the case of molybdena-alumina prepared via adsorption of gaseous MoOp(OH)t, the spectra show that a practically complete monolayer of Mo6+ oxide covers the alumina. After reduction with hydrogen the hydroxyls of the carrier appear. From the reversibility of redu...

Porous alumina film on aluminum with gel-like pore wall was prepared by a two-step anodization of aluminum, and the corresponding gel-like porous film was etched in diluted NaOH solution to produce alumina nanowires in the form of densely packed alignment. The resultant alumina nanowires were reacted with NH(3) and evaporated aluminum at an elevated temperature to be converted into densely pack...

The growth of ordered nanorods of mesoporous SBA-15 inside a porous alumina membrane has been achieved for the first time by a simple sol-gel method. The obtained SBA-15 nanorods themselves have ordered hexagonal mesochannels with a size of about 6 nm and have been arranged to form hexagonal arrays by the limitation of pores of the alumina membrane. The synthesized alumina membrane with mesopor...

a simple method for fabrication of highly ordered gold nanorod film is introduced in this article. the procedure is based on thermal evaporation of gold into a porous anodic alumina film (paa). the ppa film was fabricated by combining the hard and mild anodization. this combination effectively decreases the processing time of fabrication of highly ordered porous anodic alumina film with control...

The effect of -tricalcium phosphate additive on the alumina matrix was investigated. The sintering behaviour of the alumina tricalcium phosphate composites was characterized by using magic angle spinning nuclear magnetic resonance, X-ray diffraction, dilatometry, differential thermal analysis and scanning electron microscopy analysis. The mechanical properties of composites have been investiga...

INTRODUCTION Flexure of a dental composite can be detrimental to the success of a restoration. Flexibility considerations are thus important when comparing dental materials to optimize the success of resin restorations. AIMS AND OBJECTIVES Flexibility of 5.6 x 18.0 x 2.0 mm3 experimental alumina/feldspar and SR ADORO dental composites specimens were compared. It was hypothesized that alumina/...

The adsorption of piperidine vapor on the hydrated alumina (alpha-Al2O3, corundum) (0001) surface was investigated using vibrational broad bandwidth and scanning sum frequency generation (SFG) spectroscopy. The interfacial vibrational signature in the C-H stretching region of piperidine at the alumina (0001) surface is shown to be a sensitive spectroscopic probe revealing the adsorption mechani...