The objective of the present paper was to show the various macro-lmicrostructural appearances of the ODs materials MA 956 and PM 2000 at the surface and in the bulk after exposure to high temperatures in combustion chambers (gaseous environment). At the surface a chromium oxide layer forms above the alumina layer originally formed after preoxidation. At locations where the surface has been melt...

The corrosion behavior and passivation mechanism of S32750 super-duplex stainless steel exposed in a simulated marine atmosphere were studied using electrochemical methods, XPS SEM. Passivation local occurred on the metal surface when SDSS was atmospheric environment. film is composed two chromium-enriched layers. outer layer very thin at metal/atmosphere interface specimen with higher chromium...

The raw materials traditionally used as sources of chromium carriers (ferrochromium, chromium oxide and chromium powder) in application chromizing processes present a high price and some difficulties for ferrochromium grinding. In this work there is an assessment of the effect that has the use of the products of a reduction aluminothermic chromium concentrate on the characteristics and properti...

Graham Jones, J., and Warner, C. G. (1972). Brit. J. industr. Med., 29, 169-177. Chronic exposure to iron oxide, chromium oxide, and nickel oxide fumes of metal dressers in a steelworks. Occupational and medical histories, smoking habits, respiratory symptoms, chest radiographs, and ventilatory capacities were studied in 14 steelworkers employed as deseamers of steel ingots for periods of up to...

The molecular structures of the surface overlayers of rhenium(VI1) oxide, molybdenum(V1) oxide, tungsten(V1) oxide, chromium(V1) oxide, vanadium(V) oxide, niobium(V) oxide, and titanium( IV) oxide on y-alumina were determined by in situ Raman spectroscopy under dehydrated conditions. It was found that the dehydrated surface metal oxide structures of all the systems under study, except for suppo...

Three samples of hydrous chromium(III) oxide have been prepared by different procedures, and their electrokinetic mobilities have been measured. In mineral media, isoelectric points were found to be 8.45 0.15. This value is shifted from the solution isoelectric point by –0.35 0.15, due to the contribution of solvation energy to the energy of ionic adsorption. On the basis of a simple model, it ...

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 t...

A novel and practical procedure for preparation of imides is described using chromium(VI) oxide to catalyze the oxidation of N-alkylamides with periodic acid in the presence of acetic anhydride in acetonitrile.