Synthesis Of Oxide Ceramics Research Articles

Synthesis of Oxide Ceramics in Detonating Atmosphere

A detonation process based on 2,4,6 trinitrotoluene (TNT), used as an energetic reagent, was successfully implemented in the synthesis of a series of metal oxide ceramics. TNT offers better physicochemical and mechanical properties than the energetic compounds traditionally used in such processes, thus offering safer handling and transport conditions. The experimental procedure, which consisted to of mixing the energetic molecule with a ceramic salt, was simple to perform. The detonation products were characterized by X-ray diffraction, scanning and transmission electron microscopies, energy dispersive X-ray spectroscopy and nitrogen physisorption. The as-synthesized ceramic powders (CeO2, HfO2, Nb2O5, and In2O3) were crystalline and made of nano-sized quasi-spherical particles. This investigation provides an enhanced detonation synthesis process for elaborating ceramics. The majority of the oxide materials mentioned in this study had never previously been prepared by the detonation process.

ChemInform Abstract: A Novel Oxygen-Centered Hexanuclear Molybdenum Alkoxide Cluster, Mo6O( OEt)18.

The sol-gel approach, viz. hydrolysis of metal alkoxides and subsequent processing of the precipitated hydroxides or hydrous oxides, has become an important method for synthesis of oxide ceramics. Using this approach, the authors have recently attempted to isolate reduced molybdenum oxides by hydrolysis of appropriate molybdenum alkoxides. At present, further efforts are underway to develop rational syntheses of compounds of this type and to elucidate their spectroscopic and chemical properties.

Flame Synthesis of Nanophase Oxide Powders

ABSTRACT For several years, we have been developing a process--called Chemical Vapor Condensation (CVC)--for the high rate production of nanophase ceramic powders. This method proved to be well-suited to the synthesis of non-oxide ceramics, such as SiC and Si3N4. More recently, we have been investigating the synthesis of oxide ceramics by a similar process, except for the replacement of the original hot-wall reactor with a combustion-flame reactor. A specially designed burner is used to achieve a flat flame, extending a few millimeters out of the burner, which ensures that the temperature distribution and gas phase residence time are identical over the entire burner surface. Metalorganic precursors, introduced along with the fuel/air mixture, therefore experience completely uniform decomposition and reaction, thereby yielding an uniform nanopowder product. In this talk, we will describe the progress made in flame synthesis of SiO2, TiO2, and Al2O3 nanopowders.

Using induction melting for preliminary synthesis of oxide ceramics in the ZrO2-Y2O3-Al2O3 system

A study was made of the liquid-phase synthesis of materials in the ZrO2-Y2O3-Al2O3 system by the induction melting method in a cold crucible (IPKhT). Equipment was developed and a technology worked out for determining the optimum melting cycles. It was found that ingots of a smaller diameter have a more uniform chemical composition over the cross section. On the basis of these tests we decided that the IPKhT method is suitable for synthesizing materials used as the starting raw materials in controlled crystallization processes.