High Density Ferrite Materials for Power Transformer Applications

Abstract

The combination of highly reactive raw materials with an optimized set of dopants results in high density Mn Zn ferrites. The use of non-calcined raw materials has the advantage of simplified processes and improved cost efficiency of the industrial realization. Lowest power losses and highest saturation flux densities could be achieved as a result of substantial investigations. Both properties require a dense and defect-reduced microstructure. The spinel formation and the grain growth were optimized due to the required grain size, the composition and the grain boundary thickness. Usual additive oxides like CaO, SiO 2 and Nb 2 O 5 were amended by V 2 O 5 and SnO 2 as eutectic control. Increased transport capability for the initial chlorine content of iron oxide at moderate temperatures could be enhanced by optimized shrinkage behavior. Consequently all results were adapted to commercial raw material qualities with the result of highest performance power transformer ferrites in the frequency range up to 300 kHz.