Chromic oxide is an important basic chemical and finds many applications including metallurgical materials, green pigments, construction materials, refractory materials and catalysts. Presently, the industrial production of chromic oxide generally employs two processes (Ding, 2003): one is the reduction of sodium dichromate with ammonia sulfate; the other is the thermal decomposition of chromic...

The interaction of chromium oxide with Alz03, TiOz and SiO? supports is investigated with Raman spectroscopy. The influence of the nature of the oxide support, calcination temperature and chromium oxide loading upon the molecular state of the supported chromium oxide is determined. The Raman studies reveal that the oxide supports stabilize the chromium oxide as Cr(V1) in tetrahedral coordinatio...

the use of an inorganic phase in water-in-oil (w/o) microemulsion has recently received considerable attention for preparing metal oxide nanoparticles. this is a technique, which allows preparation of ultrafine metal oxide nanoparticles within the size range 40 to 80 nm. preparation of nano chromium (iii) oxide studied investigated in the inverse microemulsion system. therefore the nucleation o...

The European Union has banned chromium(VI) compounds in electrical and electronic equipment (EEE), such as chromate conversion coating films. Chromium(III) compounds are not banned. Using Raman spectroscopy without any preparation, we distinguished chromium(VI) oxide from chromium(III) oxide and chromium(III) hydroxide in chromate conversion coating films. Raman bands of chromium(VI) oxide were...

One factor limiting solid oxide fuel cell (SOFC) performance is the degradation of chromium containing, ferritic stainless steel, interconnects during operation. When chromium-containing steels are used as interconnect materials a chromium oxide layer forms on the surface. Under SOFC operating conditions (Cathode gas 800oC and 2.5-3.1% H2O) chromium ions are vaporized by the cathode gas and red...

The oxidation kinetics of chromium at 900~ are independent of the oxygen partial pressure. Although this observation gives evidence for a defect mechanism where chromium interstitials account for the chromium transport in the oxide scale, the experimental phenomena do not support one single model. The occurrence of oxide whiskers and oxide ridges are explained by the energy of activation for th...

A novel radio frequency magnetron sputtering method for the deposition of composite films which consist of chromium oxide and chromium ~Cr2O3/Cr-cermet! is presented. As an extension to conventional reactive sputtering of a Cr target in an argon and oxygen atmosphere the oxygen flow into the process chamber is switched periodically on and off. This leads to an oscillating oxygen partial pressur...

The use of an inorganic phase in water-in-oil (w/o) microemulsion has recently received considerable attention for preparing metal oxide nanoparticles. This is a technique, which allows preparation of ultrafine metal oxide nanoparticles within the size range 40 to 80 nm. Preparation of nano chromium (III) oxide studied investigated in the inverse microemulsion system. Therefore the nucleation o...

It has been considered that the corrosion of passive metals and alloys is not caused by the active metal-dissolution but the dissolution of a nonporous passive oxide film in aqueous solution. The corrosion current density of iron(1)(2), chromium(3) and their alloys(4) is independent of the potential in all the range of passivity, although depending upon the pH of solution. Vetter(1) explained s...