The oxidation kinetics of alumina-forming metals can be affected by adding a small amount of a reactive (normally rare earth) element oxide (RExOy) and the segregation of the reactive element (RE) ions to the growing alumina grain boundaries (GBs) has been considered as a responsible reason. However, this interpretation remains a controversial issue as to how RE ions are produced by RExOy which...

The purpose of this study was to use a tape casting technique to develop an Al2O3 fiber-reinforced Al2O3-based ceramic material (Al2O3-fiber/Al2O3 composite) into a new type of dental ceramic. The Al2O3-based ceramic used a matrix consisting of 60 wt% Al2O3 powder and 40 wt% SiO2-B2O3 powder. The prepreg sheets of Al2O3-fiber/Al2O3 composite (in which uniaxially aligned Al2O3 fibers were infilt...

Alumina toughened zirconia (ATZ) and zirconia toughened alumina (ZTA) are currently the materials of choice to meet the need for tough, strong, and bioinert ceramics for medical devices. However, the mechanical properties of ZrO2/Al2O3 dispersion ceramics could be considerably increased by reducing the corresponding grain sizes and by improving the homogeneity of the phase dispersion. Here, we ...

Next to the main aluminium ore, bauxite, an assemblage of aluminium hydroxides, aluminium oxides and other minerals (gibbsite, diaspore, boehmite, kaolinite, quartz, hematite, goethite, rutile, anatase, and alumogel), aluminium oxides find direct application in diverse industrial processes (e.g., refractory, abrasives, and watch-making industries) as well as in the gemstone sector. Corundum (Al...

Al2O3-ZrO2 ceramic coatings were prepared on 6061 Al alloy by Micro Arc Oxidation (MAO) and Selective Laser Melting (SLM). Coatings MAO exhibit a porous structure progressive oxidation of the substrate as function processing time. Those made SLM are denser, although presence cracks is observed throughout their surface. XRD results suggest that coating consists m-ZrO2, t-ZrO2 γ-Al2O3 phases for ...

Incipient wetness impregnation was used to deposit dispersed tin (Sn) atoms on γ-Al2O3. The morphology and structure of the catalysts were characterized using Raman, X-ray Photoelectron Spectroscopy (XPS), low energy ion scattering (LEIS) combined with N2-physisorption in situ infrared diffuse reflectance spectroscopy (DRIFTS) NH3 CO2 as probe molecules, H2- temperature-programmed reduction (H­...

TiCl2/nano-γ-Al2O3 as a new heterogeneous Lewis acid catalyst was synthesized and characterized by FE-SEM, XRD, FT-IR, EDS, XRF, BET and TGA. N-substituted pyrroles have been synthesized via Paal–Knorr reaction in the presence of TiCl2/nano-γ-Al2O3 at room temperature under solvent-free conditions.