Fabrication of Nano Silica Dispersed Permalloy Composite Coating

Abstract

In aqueous solution, the agglomeration of silica nanopowder is a major problem which causes poor uniformity of electroplated surfaces. Silica surface is susceptible to moisture due to the hydroxyl group on its surface which causes the silica nanopowder to become agglomerated. In this study, silica nanoparticle dispersion in the electroplated layer is reported. From zeta potential analysis, silica nanopowder has a negatively charged surface in an alkaline bath. Silica nanopowder is less agglomerated in an alkaline bath than in an acidic bath due to the surface charge. Additives change the surface morphologies of the electroplated layer as well as the silica nanopowder contents. Comparing an alkaline bath and an acidic bath, the advantage of an additive to the electroplated layer is only observed in an alkaline bath. Types of sonicators and sonication periods are also surveyed for silica nanopowder dispersion. Sonication time can be reduced by a horn-type sonicator, and longer sonication time guaranteed better silica nanopowder dispersion.