Effect of synthesis method on the structural behavior of CaFeO2.5 compound

Abstract

CaFeO2.5 samples were synthesized by solid solution, mirror furnace and Sol-gel methods. The effect of the synthesis method on the behavior structure was investigated. Phase structures are comparatively characterized and studied by means of X-ray powder diffraction. Experimental results have revealed that the synthesis method has a strong influence on the structure of the studied compounds. All samples obtained by the three methods are crystallized in the Pnma orthorhombic system.  We obtained the best results in the case of the Sol-gel technique. In the Sol-gel method, the lattice parameters obtained are a=5.41631 Å, b= 14.73899 Å and c=5.58790 Å. Also, the value of the average crystallite size D=52.03 nm and the dislocation density δ=3.69x1010/cm². Since the values ​​of the lattice parameters in this method were the smallest of the three methods, which exhibiting a weak shrink of the volume compared to the solid solution and mirror furnace one. This shrinking is a natural result of the decrease in the value of the average crystallite size and the increase of dislocation density, with a reason for the inverse relationship between them. This allows us to conclude the importance of the Sol-gel method for obtaining CaFeO2.5 nanoscale compound.