Preparation and Thermal Analysis of Mixed Magnesium‐Manganese‐Iron Oxalates and Hydrated Oxides

A square‐loop ferrite composition, Mg 0.675 Mn 0.535 –Fe 1.8000 O 4 , having high purity and fine particle size was prepared by pyrolysis of coprecipitated oxalates or hydrated oxides. The control of pH had a marked effect on the stoichiometry of the coprecipitated divalent oxalates, and ap optimum pH of 2.5 to 3.0 was observed. Thermal analysis was performed on the coprecipitated materials and on individual components; it revealed that the coprecipitated oxalates formed a solid solution whereas the hydrated oxides did not.