METHOD FOR PRODUCING NANOCRYSTALLINE METAL POWDER WITH HIGH MAGNETIC PERMEABILITY AND A METHOD FOR MANUFACTURING AN ELECTROMAGNETIC WAVE ABSORPTION SHEET, CAPABLE OF MAINTAINING UNIFORM AIR GAPS USING THE NANOCRYSTALLINE METAL POWDER

摘要

PURPOSE: A method for producing nanocrystalline metal powder with high magnetic permeability and a method for manufacturing an electromagnetic wave absorption sheet using the nanocrystalline metal powder are provided to minimize an eddy current loss, which increases rapidly at high frequencies, by forming a ceramic insulating layer between the powder to uniformly disperse air gaps.;CONSTITUTION: A method for producing nanocrystalline metal powder with high magnetic permeability is as follows: Amorphous metal is processed in a heat treatment furnace, where a magnetic field is supplied for a part of the total processing time. The amorphous metal is changed into nanocrystalline metal with high magnetic permeability through the crystallization of components(S110,S120,S130). The nanocrystalline metal is pulverized to obtain nanocrystalline metal powder(S140,S150).;COPYRIGHT KIPO 2013;[Reference numerals] (S110) Starting heat treatment of amorphous metal of fixed shape in a heat treatment furnace; (S120) Injecting nitrogen into the heat treatment furnace and applying a magnetic field to amorphous metal of fixed shape; (S130) Changing into nano crystalline metal of fixed shape with high magnetic permeability; (S140) Pulverizing nano crystalline metal of fixed shape; (S150) Obtaining nano crystalline metal powder