Microstructure characterization and properties of chemically synthesized Co2Z hexaferrite

Powders having stoichiometric composition of Co2Z (Ba3Co2Fe24O41) were prepared by gel self-propagating method and processed at different temperatures to study phase evolution process. Unlike other ferrites, Co2Z hexaferrite was not synthesized directly by gel self-propagating technique, but was formed gradually from some intermediate phases due to its complicated crystalline structure. After Z-type phase formed at relatively low temperatures of 1200°C, the powders were annealed at temperatures lower than 1200°C. It was found that, once formed, this phase was quite stable. At the same time, the morphology and distribution of hexagonal particles was improved, and ceramic samples thus achieved from the relative powders presented excellent ultrahigh frequency magnetic properties.