Patent ID: 7713465
Filing Date: 2010-05-11
Classification: C01G,C01P,C04B,H01F

Abstract:
1. A process for producing a MnZn-base ferrite comprising: firing a compacted raw material to produce the MnZn-base ferrite, wherein said firing comprises, in the following order: a heating phase comprising gradually bringing a firing temperature from room temperature up to a maximum temperature; a maximum temperature holding phase comprising maintaining the maximum temperature for a period of time, wherein a partial pressure of oxygen (p2) at said maximum temperature holding phase is greater than an equilibrium partial pressure of oxygen (p1) as follows: wherein the equilibrium partial pressure of oxygen (p1) is represented by the following equation: wherein PO a cooling phase comprising gradually bringing the maximum temperature down to near room temperature, wherein a partial pressure of oxygen (p3) at said cooling phase is operated at an equilibrium partial pressure of oxygen based on the equation log(p3)=a−b/T.