Infrared spectroscopy is used to follow the chemical changes, as a function of temperature, after sequentially adsorbing trimethylaluminum (TMA) and methanol on hydroxylated alumina. Deuterium-labeled methanol is used to distinguish between the chemistry of methyl and methoxy species. To differentiate between methanol adsorbed on TMA-derived sites and on alumina, the adsorption of methanol is s...

OBJECTIVE To describe bauxite mining and alumina refining processes and to outline the relevant physical, chemical, biological, ergonomic, and psychosocial health risks. METHODS Review article. RESULTS The most important risks relate to noise, ergonomics, trauma, and caustic soda splashes of the skin/eyes. Other risks of note relate to fatigue, heat, and solar ultraviolet and for some opera...

Introduction Nanocrystalline gamma-phase (γ) alumina is among many polytypes of alumina that find extensive applications as a catalyst and catalytic supports. The most useful properties these aluminas provide as catalyst supports are high surface area and welldefined porosity. These properties result primarily from the nano-scale crystalline character of the alumina. The problem is that both th...

A crackand pinhole-free composite membrane consisting of an a-alumina support and a modified y-alumina top layer which is thermally stable up to 1100°C was prepared by the sol-gel method. The supported thermally stable top layer was made by dipcoating the support with a boehmite sol doped with lanthanum nitrate. The temperature effects on the microstructure of the (supported and unsupported) La...

Textural evolution (porosity reduction, pore and crystallite growth) in titania-alumina composite membranes has been studied using thermal analysis, X-ray diffraction, field emission scanning electron microscopy and N, physisorption techniques. The presence of alumina in the membranes improved the thermal stability of the porous texture by retarding the anatase-to-rutile phase transformation a...

Alumina phase loaded with ammonium pyrrolidine dithiocarbamate (APDC )were synthesized based on chemical binding and physical adsorption approaches. The stability of a chemically modified APDC especially in concentrated hydrochloric acid which was then used as a recycling and pre-concentration reagent for further uses of alumina immobilized APDC phase. The application of this alumina for sorpti...

To know the electrical properties of any materials is very important for practical application of that material. In this paper I have tried to find out the proper electrical properties of Indium doped Alumina (Al2O3) for practical application of this Alumina. For this purpose all thin films are deposited on glass substrate by electron beam evaporation technique at a pressure of about 1.5 x 10-6...

The fracture rate of third-generation ceramic liners is greatly reduced compared with first- and second-generation liners because of improvements in the design and manufacturing process. Fractures of the alumina-bearing couple are rare for the same reason.This article describes a case of a fracture of an alumina-bearing couple delta ceramic liner without trauma history that was treated with cer...

Interfacial fracture toughness and cyclic fatigue-crack growth properties of joints made from 99.5% pure alumina partially transient liquid-phase bonded using copper/niobium/copper interlayers have been investigated at both room and elevated temperatures, and assessed in terms of interfacial chemistry and microstructure. The mean interfacial fracture toughness, Gc, was found to decrease from 39...