Arc Plasma Deposition of Nickel Zinc Ferrites

Abstract : Nickel zinc ferrite powders prepared by flame spraying, fluid bed reactions, and a conventional spray dried technique were deposited on ceramic substrates by arc plasma spraying. The deposition rate was dependent upon the powder preparation technique. The magnetic properties evaluated were temperature coefficient, the real part of the permeability tensor, coercive force, and squareness ratio. It was noted that the squareness ratio of arc plasma deposited ferrite was substantially higher than for the same composition conventionally densified. The arc current and the distance from the arc plasma gun to the substrate influenced the values of temperature coefficient, permeability tensor, and coercive force. Measurements of saturation magnetization and resistivity of the deposited ferrite were also made, and the reproducibility of the arc plasma was evaluated. Possible mechanisms for some of the observed phenomena are discussed.