COMPOSITE FERRITE ELECTROMAGNETIC WAVE ABSORBERS WITH HIGH FLEXIBILITY, AND FORMABILITY AND PRODUCTION THEREOF

摘要

PURPOSE: Provided is a method for producing electromagnetic wave absorbers excellent in flexibility, formability and strength by using ferrite composite, especially including synthetic resin. CONSTITUTION: The electromagnetic wave absorbers comprising ferrite are produced by the following steps of: mixing 60-68wt.% of Fe2O3, 10-14wt.% of NiO, 14-20wt.% of ZnO and 4-10wt.% of CuO (S11); adding 120-180wt.% of water, 1-3wt.% of dispersant such as ethoxylated nonylphenol phosphate and 1-2wt.% of binder such as polyvinyl alcohol to mixed materials, and wet ball-milling to make a slurry (S12); spray-drying the slurry (S13); thermal treating granulated mixtures at 600deg.C for 2-6hrs to remove remaining dispersant and binder(S14); sintering granules at 1060deg.C for 1-2hrs (S15). Also, The electromagnetic wave absorbers comprising ferrite and synthetic resin is produced by the following steps of; grinding sintered ferrite (S21); mixing 30-90wt.% of ground ferrite powder and 10-70wt.% of synthetic resin, Nylon 66, to reduce brittleness of ferrite, adding 1-5wt.%(based on the amount of ferrite powder) of silane coupling agent, gamma-aminopropyl triethoxy silane, to improve the affinity between ferrite and resin, and melting mixtures (S22); forming molten ferrite mixtures (S23).