THE following comments are directed to the sections (2) ‘‘revisit to the grain growth problems in alumina’’ and (3) grain growth without a liquid phase in the article of concern. The purpose of this comment is to challenge the authors’ assertions and refute the following arguments, namely, first that ‘‘MgO can be considered a very effective grain growth promoter in the sintering of alumina,’’ s...

Egyptian Petroleum Research Institute, Nasr City, Cairo, Egypt. Chemistry department, Faculty of Science, Taif University, KSA. _________________________________________________________________________________________ Nine alumina samples of various modification techniques were subjected to thermal analysis via thermogravimetric analysis (TGA) and differential thermal analysis (DTA), in order t...

The environmental pollution crisis has infiltrated all aspects of life, making it hard to avoid the hazards. To address this, is essential recycle industrial waste through green concrete technology, such as ground-granulated blast furnace slag (S), silica fume, and fly ash (FA). In this study, effect nano-alumina (NA) on fresh hardened stag and/or slag-based alkali-activated self-compacting (A-...

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...

By consideration of unique properties of composite Al2O3-ZrO2 such as high toughness, high wear resistant and relative low thermal expansion, in this study, nanocomposite of Al2O3-ZrO2 was produced by Mechanical activated Self propagating High-temperature Synthesis (MASHS) using laser beam for ignition. First Al and ZrO2 powders were mixed in the mole ratio of 1:1 and milled for 1, 3 and 6 hour...