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Chromium(III) oxide

About: Chromium(III) oxide is a(n) research topic. Over the lifetime, 163 publication(s) have been published within this topic receiving 2526 citation(s). The topic is also known as: green oxide of chromium & green chromium oxide.


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Journal ArticleDOI
TL;DR: In this article, a technique for studying orientation effects on nearly opaque single crystals with laser Raman spectroscopy is described in detail, and the instrument used in these studies is a Spex monochromator.
Abstract: A technique for studying orientation effects on nearly opaque single crystals with laser Raman spectroscopy is described in detail. The instrument used in these studies is a Spex monochromator. The scattering equations derived are applied to a study of iron(III) oxide and chromium(III) oxide.

179 citations

Journal ArticleDOI
TL;DR: Determination of the stabilization/destabilization mechanism of the polyamino acid/chromium (III) oxide system and examination of the effects of polymer molecular weight on the stabilization properties can contribute to a wider use of this group of compounds as potential stabilizers or flocculants in many industrial suspensions.
Abstract: In the presented paper, the influence of the molecular weight and the type of polyamino acid functional groups on the electrokinetic properties and the stability of chromium (III) oxide suspension were examined. Analysis of the data obtained from the adsorption, potentiometric titration, zeta potential, and stability measurements allows to propose stabilization or destabilization mechanism of the studied systems. In the studies, there were used polyamino acids with different ionic characters: anionic polyaspartic acid and cationic polylysine. The measurements showed that the zeta potential depends on the concentration and molecular weight of the applied polymer. Stability of the chromium (III) oxide suspensions in the presence of ionic polyamino acids increases compared to the results obtained in the absence of polymers. The exception is LYS 4,900 at pH = 10. Under these conditions, the decrease in stability is observed due to formation of polymer bridges between the polymer chains adsorbed on different colloidal particles. Determination of the stabilization/destabilization mechanism of the polyamino acid/chromium (III) oxide system and examination of the effects of polymer molecular weight on the stabilization properties can contribute to a wider use of this group of compounds as potential stabilizers or flocculants in many industrial suspensions.

142 citations

Journal ArticleDOI
TL;DR: Experimental test work with a number of slag materials indicates that very gradual oxidation of trivalent to hexavalent chromium does occur when the slag is exposed to atmospheric oxygen, rendering a quantifiable but small portion of chromium in this much more mobile and toxic form.
Abstract: Slag arising in ferrochromium and stainless steel production is known to contain residual levels of trivalent chromium. As the chromium is normally bound in the slag matrix in various silicate or spinel phases, and hence not easily mobilised, utilisation or controlled disposal of such slag is generally considered unproblematic. Experimental test work with a number of slag materials indicates, however, that very gradual oxidation of trivalent to hexavalent chromium does occur when the slag is exposed to atmospheric oxygen, rendering a quantifiable but small portion of chromium in this much more mobile and toxic form. Mechanisms and rates of the oxidation reaction were investigated in a number of long-term studies using both original slag materials and artificial mixes of chromium and calcium oxides. Powders of these materials, some of them rolled into balls, were left to age under different conditions for periods of up to 12 months. In the slag samples, which contained between 1 and 3 wt.% chromium, 1000–10 000 μg Cr(VI) were found per gram of chromium within 6–9 months of exposure to an ambient atmosphere. The rate of the oxidation reaction decreased exponentially, and the reaction could generally be said to have ceased within 12 months. In mixtures of calcium and chromium oxides the oxidation reaction is presumed to occur at the boundaries between chromium oxide and calcium oxide phases through diffusion of oxygen along the grain boundaries and of Cr 3+ across the boundaries, resulting in the formation of calcium chromate. In the slags, where calcium and chromium oxide can form a solid solution, the oxidation is likely to occur at the exposed surface of grains containing this solution.

98 citations

Journal ArticleDOI
TL;DR: The magnetic properties of Cr2O3 nanoparticles show the presence of a net magnetic moment at the surface due to the large surface/volume ratio as discussed by the authors, which modifies the classical behaviour expected for bulk antiferromagnetic particles.
Abstract: Cr2O3 nanoparticles of controlled particle size were prepared by calcination of a precursor, Cr(OH)3, obtained by precipitation with sodium hydroxide. Samples were characterized by transmission electron microscopy and x-ray diffraction. Average particle sizes ranged from 20 to 200 nm. The magnetic properties of Cr2O3 nanoparticles show the presence of a net magnetic moment at the surface due to the large surface/volume ratio. This fact modifies the classical behaviour expected for bulk antiferromagnetic particles. Below the Neel temperature, magnetization curves as a function of the applied magnetic field show the presence of coercive forces in the low-field range.

81 citations

Journal ArticleDOI
TL;DR: In this paper, Nanosized chromium oxide (Cr2O3) oxide was prepared by the common thermal decomposition of Cr(NO3)3·9H2O chromium (III) nitrate nonahydrate.
Abstract: Nanosized chromium (Cr2O3) oxide was prepared by the common thermal decomposition of Cr(NO3)3·9H2O chromium (III) nitrate nonahydrate. Prior to the heat treatment at 550 °C, the commercial reagent was first dissolved in a colloidal silica solution and then dried at a low temperature to slowly evaporate the aqueous solvent. The SiO2/Cr(NO3)3·9H2O weight ratio (R) was changed from 0 to 2. The various Cr2O3 powders were characterized by XRD, FTIR, nitrogen adsorption, SEM and TEM techniques. A maximum specific surface area of 113 m2 g−1, associated with a pore volume of 0.72 cm3 g−1, was obtained for the Cr2O3 powder prepared with R = 2. These pristine chromium oxide nanoparticles, with a slightly sintered sphere-shaped morphology, exhibited a 10 nm particle size with a monocrystalline character as demonstrated by the TEM and XRD correlation.

71 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20213
20202
20195
20184
20175
20165