Investigation of nano-crystaline strontium hexaferrite magnet powder from mill scale waste by the mechanochemical synthesis: Effect of the annealing temperature

Today, waste management and recycling have critical importance given the dwindling natural resources and to create powerful technologies for a green future. One of these strontium hexaferrite powders were produced by mechanochemical process using mill-scale and strontium carbonate from obtained celestite ore. The strontium carbonate and the mill scale were prepared in stoichiometric ratio, and mechanochemical process was applied for 16 h to produce hard-ferrite powders. Following the mechanochemical synthesis process, powder mixture was annealed at 850-1000 ? temperatures. The morphology, crystal structure and phase composition of strontium hexaferrite powders caused the magnetic properties to change according to the annealing temperature. As a result of the studies, the most suitable annealing temperature was determined as 975 C. The Hc, Br and (BH)max of produced powders correspond to 5505Oe, 347 mT and 5.77MGOe at 975 ?, respectively. The Curie tem-perature of the annealed powders was determined as 474 ?.

Automated summary

This study produced strontium hexaferrite powders using a mechanochemical process, and found that the magnetic properties can be changed by varying the annealing temperature. The most suitable annealing temperature was determined to be 975°C, leading to improved magnetic performance.