ملخص
Abstract
Mixed chromium oxides with some divalent metals such as Fe, Co, Ni, Zn,Cd and Hg were prepared by two ways:- Coprecipitation of carbonates of the intended metals then calcination of the precipitates. Calcination of ground mixtures of oxy salts that are easilydecomposable.The produced mixed oxides were characterized using X- ray diffraction and the results were matched with those of A.S.T.M (Americation society of testing materials) and agreement was observed with the patterns of the intended compounds. The particle size was calculated from the profile of the diffraction peaks. Thermal behavior (TGA and DTA) was investigated and the thermodynamics and kinetics factors were calculated. The D.C. electrical conductivity was measured at room temperature and higher temperatures from where the activation energy of conduction was calculated. The materials prepared proved to behave as semiconductors in the investigated range of temperature.