Perfectly dense ceramics of highly pure calcium manganese oxide

Immensely thermally stable and perfectly dense ceramics of highly pure calcium manganese oxide (CaMnO3) powders is realized at optimized minimal processing temperature and time using cost-effective ball-milling and hot-press techniques. The effect of ball milling time on the calcination time to prepare highly pure CaMnO3 powder and sintering time on the temperature adequate enough to achieve perfectly dense CaMnO3 ceramics is studied thoroughly and systematically. The as-synthesized single phase CaMnO3 is attained by mixing precursors of calcium carbonate and manganese oxide, using high energy ball milling for longer time followed by calcination for shorter time duration and vice-versa. A decrease in particle size in as-synthesized CaMnO3 is noticed for powders prepared with longer ball milling and shorter calcination times. The minimal time required for achieving highly pure and fine-grained powders containing sub-micrometer particles of CaMnO3 is accomplished by ball milling the precursor mixture for 12 h and calcining at 1273 K for 2 h. Relative density of 99.03% is achieved for the as-synthesized CaMnO3 powders hot pressed at 1073 K for 30 min.