Abstract
A new-type ferrite plating process using recycled waste solution was proposed in this study to attain ferrite film fabrication at low environmental load. Although spin-spray technique enables us to deposit crystallized spinel ferrite films at very low temperature (<100°C) by spraying an aqueous reaction solution and oxidizing one onto substrates, this technique exhausts large quantity of waste solution, and it detracts the point of merit of ferrite plating as eco-friendly process. In this study, the waste solution, from which iron ions were removed as precipitated iron hydroxides, was used as recycled oxidizing solution in spin-spray technique. The additional amounts of oxidizer (H2O2) and pH modifier (NH3 aq) to waste solution significantly affected to the crystallinity and saturation magnetization of ferrite films fabricated by recycling process. The recycled oxidizing solution was prepared by adding relatively small amount 0.8 ml of H2O2 to waste solution of 3.0 L and adjusting the pH at relatively high 8.8-9.0. The ferrite films fabricated by using this recycled oxidizing solution had crystallite orientation and exhibited the saturation magnetization almost same as those of ferrite films fabricated by conventional spin-spray technique using fresh solutions.
