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Semiconductor ceramic, and positive temperature coefficient thermistor

A positive temperature coefficient, thermistor technology, applied to resistors with positive temperature coefficients, resistors, non-adjustable metal resistors, etc., to achieve the effect of excellent voltage resistance

Active Publication Date: 2013-12-18
MURATA MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, the semiconductor ceramics described in Patent Document 1 contain lead

Method used

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  • Semiconductor ceramic, and positive temperature coefficient thermistor
  • Semiconductor ceramic, and positive temperature coefficient thermistor
  • Semiconductor ceramic, and positive temperature coefficient thermistor

Examples

Experimental program
Comparison scheme
Effect test

experiment example 1

[0065] In Experimental Example 1, when Er was used as the semiconducting agent Smc, the relationship between the amount of Er and the specific resistance under predetermined x, y, and t conditions was investigated.

[0066] (A) Production of raw material powder for semiconductor ceramics

[0067] Initially, prepare BaCO as the parent material 3 , CaCO 3 , SrCO 3 、Er 2 o 3 , MnCO 3 and SiO 2 of each powder. Then, each matrix material was weighed and blended. Then, add pure water and polymer dispersant, and carry out wet pulverization together with PSZ balls in a ball mill for a certain period of time. Then, it was dehydrated, dried, and heat-treated at a temperature range of 1200° C. for 2 hours to obtain a raw material powder of a semiconductor ceramic represented by formula (6). The compounding ratio of each sample number is shown in Table 2 mentioned later.

[0068] Formula (6): 100(Ba 1-(x+y+z) / 100 Ca x / 100 Sr y / 100 Er z / 100 )TiO 3 +tMn

[0069] (B) Fabricat...

experiment example 2

[0083] In Experimental Example 2, Er was used as the semiconducting agent Smc, and when the values ​​of x, y, and t were changed, the specific resistance under the conditions of each x, y, and t became extremely small. Er Quantity min . In the experiment, change the amount of Er by 0.025 to obtain z min . Table 3 shows z under the conditions of each x, y, t min value. It should be noted that the manufacturing method of the positive temperature coefficient thermistor element is the same as that of Experimental Example 1.

[0084] [table 3]

[0085]

[0086] It can be seen from Table 3 that when the amount of Ca x and the amount of Sr y increase, z min showing a decreasing trend. In addition, when the amount of Mn t increases, z min There is an increasing trend.

[0087] Next, in the order of (A) to (D), the z min formula.

[0088] Sample numbers 11 to 18 of (A) are z when the Ca amount x is changed under the conditions of y=0.000 and t=0.100 min the result of. H...

experiment example 3

[0095] In Experimental Example 3, Er was used as the semiconducting agent Smc, and the specific resistance, static withstand voltage, and resistance double point were obtained when the values ​​of x, y, z, and t were changed respectively. The resistance double point is the temperature at which the resistance value at 25° C. is doubled.

[0096] Table 4 shows the results. As the calculated value of Er, f using the above formula (1) is described 3 The value of the computed value of (x, y, t). In addition, similarly to Experimental Example 1, the static withstand voltage lower limit value in the specific resistance of each sample is shown. The specific resistance was set to be 1000Ω·cm or less, which was practically no problem. In addition, 115-140 degreeC was set as acceptable about the resistance double point.

[0097] [Table 4]

[0098]

[0099] In sample numbers 41, 48, and 53, the Ca amount x was as small as 0.000, and the static withstand voltage value was smaller t...

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Abstract

The purpose of the present invention is to provide: a semiconductor ceramic having excellent pressure resistance; and a positive temperature coefficient thermistor element produced using the semiconductor ceramic. A semiconductor ceramic, which constitutes a component base (11) of a positive temperature coefficient thermistor element (1), contains a compound represented by the general formula (Ba1-(x+y+z) / 100Cax / 100Sry / 100Smcz / 100)TiO3 (wherein Smc represents an agent capable of making materials semiconductive) as the main component, and is characterized in that Mn is contained in an amount of t part by mole relative to 100 parts by mole of the main component, x, y and t fulfill the relationship represented by the formulae 2.500 <= x <= 20.000, 0.000 <= y <= 5.000, 2.500 <= x+y <= 20.000 and 0.030 <= t <= 0.150, and z is equal to or greater than an amount of the agent for making materials semiconductive (Smc) at which the specific resistance becomes minimum in a curve that is defined by x, y and t and shows the relationship between the amount of the agent for making materials semiconductive (Smc) and the specific resistivity.

Description

technical field [0001] The present invention relates to semiconductor ceramics, and particularly to semiconductor ceramics having a positive temperature coefficient of resistance (Positive Temperature Coefficient; hereinafter, referred to as “PTC characteristics”). Also, it relates to a positive temperature coefficient thermistor using the semiconductor ceramic. Background technique [0002] Barium titanate (BaTiO 3 )-based semiconductor ceramics have PTC characteristics in which the resistance value increases rapidly when the Curie point Tc at which the phase transition from the tetragonal crystal to the cubic crystal is exceeded exceeds the Curie point Tc when voltage is applied. Utilizing this PTC characteristic, semiconductor ceramics are widely used for heating applications, motor starting applications, and the like. [0003] For example, in Patent Document 1, it is described that BaTiO is contained in a certain ratio as a semiconductor ceramic having PTC characterist...

Claims

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Application Information

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IPC IPC(8): C04B35/468H01C7/02
CPCC04B35/4682C04B2235/3208C04B2235/3213C04B2235/3224C04B2235/3225C04B2235/3262C04B2235/3298C04B2235/3418H01C7/025
Inventor 后藤正人松永达也
Owner MURATA MFG CO LTD
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