The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 2021
Filed:
Mar. 24, 2017
Hitachi Metals, Ltd., Tokyo, JP;
HITACHI METALS, LTD., Tokyo, JP;
Abstract
A method for producing MnZn ferrite comprising Fe, Mn and Zn as main components, and Ca, Si and Co, and at least one selected from the group consisting of Ta, Nb and Zr as sub-components, comprising a step of molding a raw material powder for the MnZn ferrite to obtain a green body, and a step of sintering the green body; the sintering step comprising a temperature-elevating step, a high-temperature-keeping step, and a cooling step; the cooling step including a slow cooling step of cooling in a temperature range of 1100° C. to 1250° C. at a cooling speed of 0° C./hour to 20° C./hour for 1 hours to 20 hours, and a cooling speed before and after the slow cooling step being higher than 20° C./hour; the MnZn ferrite having a volume resistivity of 8.5 Ω·m or more at room temperature, an average crystal grain size of 7 μm to 15 μm, and core loss of 420 kW/mor less between 23° C. and 140° C. at a frequency ofkHz and an exciting magnetic flux density of 200 mT.