5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Structural And Electrical Characterization Of Srceo3 And Sr2ceo4:a Comparative Study

Extensive research has been carried out on SrCeO3, reported aspotential candidate forsolid electrolyte of intermediate temperature solid oxide fuel cells [1]. Strong emission exhibited by rare-earth doped Sr2CeO4 in visible range makesit a potential candidate for applications in field emission displays (FEDs) [2]. Sr2CeO4 is a compound closely related to perovskite compound SrCeO3 is composed of SrO layers separating by SrCeO3 block layers. Electrical properties of SrCeO3as well asoptical propertiesof Sr2CeO4have been well studied. Hence, to explore more applications the electrical properties of Sr2CeO4have been studied and compared with electrical properties of SrCeO3,is considered worthwhile. Therefore, in this work synthesis of the SrCeO3 and Sr2CeO4 has been carried via conventional solid state reaction route using high purity ( ≥ 99 %) raw materials SrCO3 and cerium ammonium nitrate (NH4)2Ce(NO3)6. Thermal analysis (TGA/DSC) of the mixture of raw materials prepared for both the compounds illustrated that the decomposition of cerium ammonium nitrate (NH4)2Ce(NO3)6into CeO2 occurs in the temperature RT-200oC whereas of SrCO3 into SrO above 800oC.Thermal analysis (TGA-DSC) of a stoichiometricmixture of raw materials SrCO3and CeO2for SrCeO3 (1 mole : 1mole ) and Sr2CeO4(2 mole : 1 mole) hasbeen carried out up to 1000oC with a heating rate of 10oC/min in N2 gas atmosphere were recorded. TGA-DSC curves areshown in Fig.1 (a) and 1(b) respectively for SrCeO3 and Sr2CeO4. The TGA curves show total weight loss approximately 13.48 % and 20.41%accompaniedby an endothermic peak in DSC curvesat 900oC and 950oC for SrCeO3 and Sr2CeO4, respectively. The endothermic peak is attributed to the reaction between raw materials to form desiredphase SrCeO3and Sr2CeO4. Based on the results of thermal analysis, mixturesof raw materials were calcined at 1000oCfor 14 h. Rietveld refinement of the XRD dada (Fig.1) confirmed that both the compounds haveorthorhombic crystal structure with space group Pnma and Pbam for SrCeO3 and Sr2CeO4, respectively. The values of lattice parameters and cell volume are presented in Table 1. The crystalline sizes (D) have been calculated for high intensity Bragg’s peak corresponding to (112) and (130) reflection for SrCeO3 and Sr2CeO4by using Scherer’s formula and given in Table 1. The experimental density (d_exp) of the sintered pellets of the samples is obtained using Archimede’s principle and the theoretical density (d_th) from their molecular weight and lattice parameters. The percentage porosity of the samples was calculated using obtain the value of experimental and theoretical density as shown in Table 1. Scanning electron micrograph (SEM) of the fracture surfaces of sintered pellets of SrCeO3 and Sr2CeO4 shows dense structure with negligible porosity. The average grain size of the samples was calculated using ‘ImageJ’ software and found to be 1.99 and 2.84µm for SrCeO3 and Sr2CeO4 , respectively. compounds haveorthorhombic crystal structure with space group Pnma and Pbam for SrCeO3 and Sr2CeO4, respectively. The values of lattice parameters and cell volume are presented in Table 1. The crystalline sizes (D) have been calculated for high intensity Bragg’s peak corresponding to (112) and (130) reflection for SrCeO3 and Sr2CeO4by using Scherer’s formula and given in Table 1. The experimental density (d_exp) of the sintered pellets of the samples is obtained using Archimede’s principle and the theoretical density (d_th) from their molecular weight and lattice parameters. The percentage porosity of the samples was calculated using obtain the value of experimental and theoretical density as shown in Table 1. Scanning electron micrograph (SEM) of the fracture surfaces of sintered pellets of SrCeO3 and Sr2CeO4 shows dense structure with negligible porosity. The average grain size of the samples was calculated using ‘ImageJ’ software and found to be 1.99 and 2.84µm for SrCeO3 and Sr2CeO4 , respectively.
Dharmendra Yadav, Upendra Kumar, Shail Upadhyay