Preparation and characterization of Mn0.43Ni0.9CuFe0.67O4 by a polymerized complex method

Mn0.43Ni0.9CuFe0.67O4 nano-sized powders were synthesized by the Pechini method for the first time. A spinel-type phase was attained from calcining of the polymerized gel precursor at 400 - 700 degrees C. The thermal evolution, surface morphology, and structural behavior have been studied by TG/DTA, SEM, XRD and FT-IR. It was found that the material decomposes upon heating above 300 degrees C. The monoclinic structure of CuO was found to be coexistent with the spinel-type phase in both the calcined powders and the sintered ceramics. The electrical properties were deeply affected by the crystal phase of CuO. The ceramics sintered at 1100 degrees C showed the best electrical properties as well as the density, of which the relative density was measured to be about 96%. The resistivity rho(25 degrees C) is about 600 Omega cm and B25 degrees C/50 degrees C is about 2000. (c) 2008 Elsevier B.V. All rights reserved.