Ferrite ceramics, ferrite sintered plate and ferrite sintered sheet

• US 10,128,029 B2
• Filed: 10/30/2014
• Issued: 11/13/2018
• Est. Priority Date: 10/31/2013
• Status: Active Grant

• Current Assignee: TODA Kogyo Corporation
• Original Assignee: TODA Kogyo Corporation
• Inventors: Okano, Yoji, Dote, Tomohiro, Sadai, Makoto, Honda, Shingo, Nakai, Katsumi, Fujii, Yasuhiko
• Primary Examiner(s): Pleszczynska, Joanna
• Application Number:
  US15/032,711
• Publication Number:
  US 20160284453A1
• Time in Patent Office: 1,475 Days
• Field of Search: 428156, 428702
• CPC Class Codes: C04B 2235/3272 Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
• CPC Class Codes: C04B 2235/3275 Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
• CPC Class Codes: C04B 2235/3279 Nickel oxides, nickalates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3281 Copper oxides, cuprates or oxide-forming salts thereof, e.g. CuO or Cu2O
• CPC Class Codes: C04B 2235/3284 Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
• CPC Class Codes: C04B 2235/6025 Tape casting, e.g. with a doctor blade
• CPC Class Codes: C04B 2235/72 Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/726 Sulfur content
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 35/26 based on ferrites
• CPC Class Codes: C04B 35/62625 Wet mixtures
• CPC Class Codes: C04B 35/62675 characterised by the treatment temperature
• CPC Class Codes: C04B 35/638 Removal thereof
• CPC Class Codes: H01F 1/10 non-metallic substances, e.g. ferrites , e.g. [(Ba,Sr)O(Fe2O3)6] ferrites with hexagonal structure
• CPC Class Codes: H01F 1/344 Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142

Abstract

An object or technical task of the present invention is to provide a ferrite sintered sheet having a dense ferrite microfine structure which has a large μ′ value, a small μ″ value, and a small temperature-dependent change of the μ′ value thereof. The present invention relates to a ferrite ceramics having a composition comprising 47.5 to 49.8 mol % of Fe₂O₃, 13.5 to 19.5 mol % of NiO, 21 to 27 mol % of ZnO, 7.5 to 12.5 mol % of CuO and 0.2 to 0.8 mol % of CoO, all of the molar amounts being calculated in terms of the respective oxides, the ferrite ceramics further comprising 0.2 to 1.4% by weight of SnO₂ and 0.005 to 0.03% by weight of S and having a density of 5.05 to 5.30 g/cm³; and a ferrite sintered sheet comprising the ferrite sintered plate on a surface of which a groove or grooves are formed, and an adhesive layer and/or a protective layer formed on the ferrite sintered plate.

Claims

1. A ferrite sintered sheet comprising a ferrite sintered plate, an adhesive layer or a protective layer that is formed on one surface of the ferrite sintered plate, and an adhesive layer or a protective layer that is formed on an opposite surface of the ferrite sintered plate,

wherein the ferrite sintered plate comprises a ferrite ceramics having a composition comprising 47.5 to 49.8 mol % of Fe₂O₃, 13.5 to 19.5 mol % of NiO, 21 to 27 mol % of ZnO, 7.5 to 12.5 mol % of CuO and 0.2 to 0.8 mol % of CoO, all of the molar amounts being calculated in terms of the respective oxides, which ferrite ceramics further comprises 0.2 to 1.4% by weight of SnO₂ and 0.005 to 0.03% by weight of S based on a weight of ferrite ceramics having the composition, and

wherein a temperature-dependent change of a μ

′

value of the ferrite sintered sheet calculated as a ratio of a difference between a real part μ

′

₈₅ of a magnetic permeability of the ferrite sintered sheet measured at 85°

C. and a real part μ

′

₂₅ of a magnetic permeability of the ferrite sintered sheet measured at 25°

C. to the real part μ

′

₂₅ ((μ

′

₈₅−

μ

′

₂₅)/μ

′

₂₅)) is 5 to 30%.

2. The ferrite sintered sheet according to claim 1, wherein the ferrite sintered plate has a density of 5.05 to 5.30 g/cm³.

3. The ferrite sintered sheet according to claim 1, wherein at least one groove is formed on at least one surface of the ferrite sintered plate.

4. The ferrite sintered sheet according to claim 1, wherein the ferrite sintered plate is divided into parts.

5. The ferrite sintered sheet according to claim 1, wherein a μ

′

value of the ferrite sintered sheet measured at 25°

C. is 90 to 180.

6. The ferrite sintered sheet according to claim 1, wherein a μ

″

value of the ferrite sintered sheet measured at 25°

C. is 0.05 to 5.