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Semiconductor ceramic composition

A ceramic composition and semiconductor technology, applied in the direction of titanium compounds, bismuth compounds, electrical components, etc., can solve the problems of inability to obtain performance, inability to form complete solid solutions, etc., and achieve the effect of high jump characteristics

Inactive Publication Date: 2010-12-08
HITACHI METALS LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this calcination has a problem that although the volatilization of Bi is suppressed, a complete solid solution cannot be formed and desired properties cannot be obtained

Method used

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  • Semiconductor ceramic composition
  • Semiconductor ceramic composition
  • Semiconductor ceramic composition

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preparation example Construction

[0060] In at least one of the step of preparing the calcined BT powder and the step of preparing the calcined BNT powder as described above, or in the step of mixing various calcined powders, when Si is added in an amount of 3.0 mol% or less Si oxides or Ca oxides or Ca carbonates are added in an amount of 4.0 mol% or less, Si oxides can suppress the abnormal growth of crystal grains, and can also facilitate the control of resistivity, and Ca oxides or Ca carbonates Sinterability at low temperature can be improved and reducibility can be controlled. When these components are added in an amount exceeding the above-mentioned limit, the component does not exhibit semiconductivity, which is not preferable. This addition is preferably performed prior to mixing in each step.

[0061] The mixed calcined powder obtained in the step of mixing the calcined BT powder and the calcined BNT powder is shaped by a desired shaping means. If necessary, the pulverized powder may be granulated ...

example

[0081] Preparation and blending of BaCO 3 、TiO 2 and La 2 o 3 The raw material powder in order to become (B 0.994 La 0.006 )TiO 3 , followed by mixing in pure water. The mixed raw material powder thus obtained was calcined in the atmosphere at the temperature shown in Table 1 for 4 hours to prepare the calcined BT powder.

[0082] Prepare and mix Na 2 CO 3 、 Bi 2 o 3 and TiO 2 The raw material powder in order to become (Bi 0.5 Na 0.5 )TiO 3 , followed by mixing with a dry mixing machine. The mixed raw material powder thus obtained was calcined at 800° C. for 2 hours in the atmosphere to prepare the calcined BNT powder.

[0083] The calcined BT powder and calcined BNT powder prepared above were mixed in a molar ratio of 73:7. Using pure water as a medium, the resulting mixture was mixed and pulverized by a ball mill until the central particle diameter of the mixed calcined powder became 1.0 μm to 2.0 μm, followed by drying. PVA was added to the pulverized powde...

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Abstract

This invention provides a semiconductor ceramic composition comprising BaTiO3 in which a part of Ba has been replaced by Bi-Na. The semiconductor ceramic composition can realize any desired control of jump characteristics while maintaining a low room temperature resistivity. A semiconductor ceramic composition comprising BaTiO3, in which a part of Ba has been replaced by Bi-Na, a p-type semiconductor being present in grain boundaries, is produced. In this case, the room temperature resistivity is controlled at any desired value while maintaining high jump characteristics by varying the proportion of the p-type semiconductor present in the grain boundaries, for example, by calcination conditions, the amount of additives, and sintering conditions.

Description

technical field [0001] The invention relates to a semiconductor ceramic composition with positive resistance temperature, which is used for PTC thermistors, PTC heaters, PTC switches, temperature detectors and the like. Background technique [0002] including BaTiO with various semiconductor dopants added 3 The composition of is generally recommended as a material exhibiting PTCR characteristics (Positive Temperature Coefficient of Resistance). Those compositions have a Curie temperature of about 120°C. Depending on the application, the Curie temperature of those compositions needs to be varied. [0003] For example, it has been proposed that by adding SrTiO 3 to BaTiO 3 to change the Curie temperature. In this case, however, the Curie temperature only changes negatively, not positively. Currently, only PbTiO 3 Considered as an additive material for positively changing the Curie temperature. However, due to the PbTiO 3 Contains elements that cause environmental poll...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/46H01C7/02
CPCC01G23/002C04B2235/5445C04B2235/3201C04B35/62675C04B35/4682C04B2235/6567C04B2235/80C04B2235/608C04B2235/3294C04B2235/6584C04B35/62685C01P2002/52C04B2235/3224C04B2235/3234C04B2235/3298C04B2235/3418C01G23/006C04B2235/85C01P2006/40C01G29/006C04B2235/3208H01C7/025C04B2235/3251C04B2235/3227C04B2235/656C04B2235/5436C01G23/003
Inventor 岛田武司
Owner HITACHI METALS LTD
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