A BALUN transformer core material contains a Z-type hexagonal system ferrite having an in-plane anisotropy and a high magnetic permeability and such a high resonance frequency as to be in excess of a Snake's limiting line, and therefore, in the BALUN transformer core material, the frequency properties of the magnetic permeability are extremely good. A BALUN transformer core obtained by pressing and sintering this BALUN transformer core material has a high initial magnetic permeability and specific resistance. Moreover, a BALUN transformer obtained by applying a winding to the BALUN transformer core is provided with superior properties which are not poorer as compared with a BALUN transformer constituted of a conventional spinel ferrite, and it is a BALUN transformer having high properties which can be used in a high-frequency band of 300 MHz or more.

BALUN transformer core material, BALUN transformer core and BALUN transformer

The manganese-zinc system ferrite of the invention has an initial permeability μi at a frequency of 100 kHz and at 25° C. of 5,000 or more, and a core loss Pcv at a frequency of 100 kHz and at 200 mT and 40° C. of 400 kW/m 3 or less.

Manganese-zinc system ferrite

Measurement of the impedance and complex resistivity of a sample is used for measuring parameters resulting from a change in physical or chemical state A variable frequency signal is provided by a transformer primary coil A secondary coil of the transformer with a closed loop and electrically coupled said sample is monitored along with a leakage current sensor Sampling at multiple signal frequencies is performed at the multiple signal frequencies

Pore structure analyzer based on non-contact impedance measurement for cement-based materials

This invention provides an Mg-based ferrite having a high dielectric breakdown voltage and a saturation magnetization suitable for electrophotographic development, a carrier containing the ferrite, and an electrophotographic developer containing the carrier. The Mg-based ferrite material of this invention comprises Li, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ti, Zr, Hf, V, Nb, Ta, Al, Ga, Si, Ge, P, Sb, Bi or a combination thereof. The Mg-based ferrite material has a saturation magnetization of 30 to 80 emu/g, and a dielectric breakdown voltage of 1.5 to 5.0 kV. The Mg-based ferrite material can realize high image quality, and be in compliance with environmental regulations.

A mg-based ferrite, an electrophotographic development carrier containing the ferrite, and a developer containing the carrier

A heat resistant cushion material (10, 20) for molding press is composed by laminating a base (10B) and felt material layers (1A, 1B, 1C, 1D).  The cushion material (10, 20) has at least one felt material layers (1A, 1B, 1C, 1D) containing heat resistant staple fibers, respectively, on the front surface and the back surface of the base (10B).  In the cushion material (10, 20), a plurality of pile-erected fiber bodies (30) consisting of staple fibers of fine size are formed in the thickness direction of the cushion material (10, 20) while penetrating the base (10B) and connect all felt material layers.  Consequently, temperature rise regulation and cushioning of the cushion material (10, 20) are improved.

Heat resistant cushion material for molding press

PURPOSE: To cut down power loss in a high-frequency region by a method wherein specific amounts of silicon oxide, calcium oxide, tin oxide and/or titanium oxide, niobium oxide. zirconium oxide are contained in the material of ferrite. CONSTITUTION: As for the main components, mangenese oxide, zinc oxide and iron oxide are contained and as for the sub components, silicon oxide, calcium oxide, tin oxide and/or titanium oxide, niobium oxide and zirconium oxide are contained. At this tiem, the contents of mangnese oxide in the main contents is 30-41mol% in terms of MnO, 6-16mol% of zinc oxide in terms of ZnO. On the other hand, the weight ratio of the sub components to the main components is 50-250-ppm of silicon oxide in terms of SiO 2 , 200-1500ppm of calcium oxide in terms of CaO, not exceeding 4000ppm of tin oxide in terms of SnO 2 , not exceeding 3000ppm of titanium oxide in terms of TiO 2 and the total of the tin oxide and titanium oxide exceeds 3000ppm. COPYRIGHT: (C)1995,JPO

Ferrite and ferrite core for power supply

A manganese-zinc ferrite having a high initial permeability in a wide band, especially an especially high initial permeability in a low-frequency region of about 10 kHz and a method for producing the same. The method including a main temperature maintaining step of maintaining the temperature at 1200° to 1450 °C during baking is characterized in that before the main temperature maintaining step the method includes an in-baking temperature decreasing step in which the lowest temperature is in the range from 1000° to 1400 °C which is 50 °C or more lower than the temperature maintained in the main temperature maintaining step. The thus produced manganese-zinc ferrite contains as main components 50 to 56 mol% of iron oxide in terms of Fe2O3, 22 to 39 mol% of manganese oxide in terms of MnO, and 8 to 25 mol% of zinc oxide in terms of ZnO and has an average grain size of 50 to 150 νm.

Manganese-zinc ferrite and method for producing the same

The initial permeability of a manganese-zinc ferrite in the high-frequency zone of 10-500 Khz is improved by mixing a manganese-zinc ferrite comprising 50-56 mole % of Fe2O3, 22-39 mole % of Mno and 8-25 mole % of Zno with at most 800 ppm (in terms of Bi2O3) of bismuth oxide component and at most 1,200 ppm (in terms of MoO3) of molybdenum oxide component and firing the mixture. The mean crystal grain diameter is adjusted to 5-50 νm or less.

Manganese-zinc ferrite.

A Mn-Zn-base ferrite comprising a main component comprising manganese oxide, zinc oxide and iron oxide and an auxiliary component containing bismuth oxide and molybdenum oxide. It is prepared by sintering a mixture of the main component comprising 22.0 to 25.0 mol% of manganese oxide in terms of MnO, 22.0 to 25.0 mol% of zinc oxide in terms of ZnO and the balance of iron oxide in terms of Fe2O3 with the auxiliary component containing 50 to 400 ppm of bismuth oxide in terms of Bi2O3 and 50 to 400 ppm of molybdenum oxide in terms of MoO3. The initial permeability at 10 kHz is at least 8500 at -20 to 20 DEG C and at least 10000 at 20 to 100 DEG C. That is, the relationship between the permeability and the temperature is good.

Manganese-zinc base ferrite

For the purpose of improving the initial magnetic permeability of manganese-zinc system ferrite in the high-frequency band of 10 kHz to 500 kHz, a manganese-zinc system ferrite comprising 50-56 mol % of Fe 2 O 3 , 22-39 mol % of MnO, and 8-25 mol % of ZnO is fired after adding thereto up to 800 ppm calculated as Bi 2 O 3 of a bismuth oxide component and up to 1,200 ppm calculated as MoO 3 of a molybdenum oxide component in admixture. It has an average grain diameter of from 5 to 50 μm.

Shoji Inoue

Papers

Ferrite and ferrite core for power supply

Manganese-zinc ferrite and method for producing the same

Manganese-zinc ferrite.

Manganese-zinc base ferrite

Manganese-zinc system ferrite