Abstract
The effect of calcination and ball-milling on the sintering and magnetic characteristics of iron-rich Ni.Zn ferrite is investigated. Results are summarized as follows.
It has serious effects on the properties of ferrite powder whether recrystalization is finished or not at the calcination process. When calcined above the recrystalization temperature, the average particle size of ferrite powder is closely related to the tap density, shrinkage and magnetic properties. When calcined below this temperature, however, the deviation from the above mentioned relations were observed. This is explained by the fact that in the latter a particle has more pores.
There are also close interrelations between permeability and porosity calculated from the volume and X-ray density and the characteristics of sintered ferrite itself ; with increasing porosity, μs ' and μs " become smaller but μs" is no so closely related to porosity. The product μs' × Q has a maximum value at 10-15% porosity.
