Magnetic Phase Formation in CoTi-Substituted Ba Hexaferrite Coatings Prepared with Atmospheric Plasma Spraying
Abstract:Thick coatings of CoTi-substituted Ba hexaferrite with the nominal composition BaCoTiFe10O19 were prepared using atmospheric plasma-spraying technology. The coatings were prepared from prereacted powders of the desired composition. The as-deposited coatings showed a high degree of crystallinity. A detailed investigation of the coatings' phase compositions was conducted with micro-Raman spectroscopy and energy-dispersive X-ray spectroscopy. Two magnetic ferrite phases, CoTi-substituted Ba hexaferrite and Co ferrite, were identified in the coatings. An X-ray powder-diffraction analysis and a quantitative structural analysis based on Rietveld refinement showed that the mass ratio of the two phases and their chemical composition varied with respect to the spraying parameters. Consequently, the static and microwave magnetic properties of the as-sprayed coatings also varied. We were able to explain the formation of the two ferrite phases based on the interplay between the partial melting of the feedstock powder and the recrystallization kinetics.
Document Type: Research Article
Affiliations: 1: Department for Materials Synthesis, Jožef Stefan Institute, 1000 Ljubljana, Slovenia 2: Department of Materials and Environmental Engineering, University of Modena and Reggio Emilia, 41100 Modena, Italy 3: Surface Engineering Institute, RWTH Aachen University, 52070 Aachen, Germany 4: VTT Technical Research Centre of Finland, FIN-02044 VTT, Finland 5: INRIM, Electromagnetism Division, 10135 Turin, Italy
Publication date: September 1, 2010