Abstract: Provided is a process for producing a MnZn-base ferrite comprising: firing a compacted raw material to produce the MnZn-base ferrite, wherein the 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 the maximum temperature holding phase is greater than an equilibrium partial pressure of oxygen (p1) as follows: p2>p1, wherein the equilibrium partial pressure of oxygen (p1) is represented by the following equation: log(p1)=log(PO2)=a?b/T, wherein PO2 is measured in a unit of %, and T is measured in a unit of absolute temperature K; and a cooling phase comprising gradually bringing the maximum temperature down to near room temperature, wherein a partial pressure of oxygen (p3) at the cooling phase is operated at an equilibrium partial pressure of oxygen bas

Abstract: Firing is carried out such that for operation of a partial pressure of oxygen and temperature at the high-temperature holding operation phase and cooling operation phase, the following equilibrium relation equation (1) indicative of an equilibrium relation of a partial pressure of oxygen (PO2 in %) to a temperature (T in absolute temperature K) is used to set the values of a and b at given values of a=a* and b=b*, respectively, Log(PO2)=a?b/T ??Eq.

Abstract: The present invention provides a production method of spherical oxide powder which includes a feeding step in which a granular powder composed of an oxide composition is fed into a combustion flame together with a carrier gas; a melting step in which said fed granular powder is melted in said combustion flame to obtain a melt; and a solidifying step in which said melt is solidified by being moved and placed outside said combustion flame.

Abstract: There is provided an apparatus for producing a spherical powder, comprising a cylindrical chamber having an axis extending in the vertical direction and a burner 30 provided in the upper part of the chamber to generate a combustion flame in the chamber, characterized in that the aggregate-crushing gas G is injected from the periphery part of the first supply pipe 61, which constitutes a raw material powder supply route O, into the first supply pipe 61. This configuration can allow a raw material powder to be supplied to the combustion flame with an aggregate of the raw material powder crushed, and suppress generation of coarse particles or unmelted particles resulting from aggregation of particles. The raw material powder to be supplied to the apparatus for producing a spherical powder may have a treating agent such as stearic acid, or a coupling agent added thereto for preventing aggregation.

Abstract: An oxide of a transition metal element having at least two valences less than 4 is contained in a spherical dielectric ceramic powder. According to a composite dielectric material using the dielectric ceramic powder, the electric resistivity can be made to take such a high value as 1.0×1012 ?·cm or more while satisfactory dielectric properties are being maintained.

Abstract: The present invention provides a dielectric ceramic powder which can secure fluidity of the mixture with a resin, even when produced by milling. The dielectric ceramic powder, when controlled to have a specific surface area of 9 m2/cm3 or less and a lattice strain of 0.2 or less can secure fluidity of the mixture with a resin, even when it is produced by milling to have particles of indefinite shape, and give a composite dielectric material of excellent dielectric properties.

Abstract: The present invention provides a production method of spherical oxide powder which includes a feeding step in which a granular powder composed of an oxide composition is fed into a combustion flame together with a carrier gas; a melting step in which said fed granular powder is melted in said combustion flame to obtain a melt; and a solidifying step in which said melt is solidified by being moved and placed outside said combustion flame.