Plasma Spraying of Magnetite Coatings for M.W. Applications

The possibilities of arc - plasma spray deposition of polycrystalline ferromagnetic coating are investigated. Powder sintered microwave absorbing ferrite materials were deposited by arc-plasma jet on polycrystalline substrates. By varying the distance between plasma torch and substrates and the spray duration, coatings with different thickness and porosity were obtained. The coatings characteristics were studied by optical, SEM and XRD methods. The mechanism of the magnetic structure formation was controlled by Mössbauer spectroscopy. The microwave absorption at 9.4 GHz, measured using a standard waveguide equipment was found to be 26%