HIGH-STRENGTH POWDER MAGNETIC CORE, METHOD OF MANUFACTURING HIGH-STRENGTH POWDER MAGNETIC CORE, CHOKE COIL, AND METHOD OF MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To provide a cheap high-strength powder magnetic core which is excellent in soft magnetic property, which achieves high pressure ring strength, and which does not use glass powder and the like, to provide a method of manufacturing the high-strength powder magnetic core, and to provide a choke coil and a method of manufacturing the same. SOLUTION: Soft magnetic alloy powder having Fe-Si-Al alloy such as sendust as a principal component is covered with methyl phenyl silicone varnish and drying by heating at around 200 °C is performed. Then, metal salt of stearic acid is mixed as a lubricant in order to speed up the thermal decomposition rate of methyl group. In this embodiment, 0.3 mass% of zinc stearate is mixed as this lubricant. A compact is formed by performing pressure forming at a pressure of 1,700 MPa at a room temperature. Methyl phenyl silicone varnish dried by heating acts as a binder when forming. High-strength powder magnetic core is formed by allowing the compact to be subjected to a heat treatment at around 600 to 800°C in an oxygen atmosphere (atmosphere). COPYRIGHT: (C)2010,JPO&INPIT