YBa2Cu3O(x) superconductor was synthesized using Y2BaCuO5, BaCuO2, and CuO powder mixture. Reaction temperatures were identified using differential thermal analysis (DTA) and thermogravimetry (TG) for syntheses of precursor powders and the powder mixtures. Appropriate reaction temperatures for Y2BaCuO5 and BaCuO2 precursor powders were 950 and 930-degrees-C, respectively. Two endothermic reactions involving melt formations were identified on the DTA and TG curves of the powder mixture, and the liquid increased the reactivity of the YBa2Cu3O(x) formation. Powder mixture samples were sintered at various temperatures ranging from 880 to 1000-degrees-C. Microstructural and X-ray powder diffraction studies showed YBa2Cu3O(x) and impurities to be formed in the samples sintered at various temperatures. The samples sintered at 990 and 1000-degrees-C showed dense microstructures. The critical temperature was 84 K for the sample sintered at 880-degrees-C and rose to 92 K as the sintering temperature increased.