NTC heat-sensitive conductive ceramic material and method of manufacturing the same

A conductive ceramic material and a technology for preparing ceramics, applied in the field of conductive ceramic materials, can solve the problems of high production energy consumption, low B value, high tin price, etc., and achieve the effects of simple preparation process, reduced price and production energy consumption

Inactive Publication Date: 2011-07-20
GUILIN UNIV OF ELECTRONIC TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Some scholars have found that doping a small amount of lanthanum in barium stannate can make it have NTC effect. Since then, people have carried out a series of doping studies on barium stannate or strontium stannate, and obtained a series of valuable research results, but found that There are the following problems: for barium stannate-based NTC thermosensitive conductive ceramics, low room temperature resistivity can be obtained after doping, but the B value is low, which is not suitable for use at room temperature; for strontium stannate-based NTC thermosensitive conductive ceramics, ordinary doped The heterogeneous method is very difficult to semiconduct; NTC heat-sensitive conductive ceramics prepared with barium stannate or strontium stannate as the matrix usually have a sintering temperature of 1450-1550 ° C without adding any sintering aids, and the production energy consumption is extremely high And the price of tin is relatively expensive

Method used

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  • NTC heat-sensitive conductive ceramic material and method of manufacturing the same
  • NTC heat-sensitive conductive ceramic material and method of manufacturing the same
  • NTC heat-sensitive conductive ceramic material and method of manufacturing the same

Examples

Experimental program
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Effect test

Embodiment 1

[0018] with SnO 2 , Fe 2 o 3 、BaCO 3 Raw materials are mixed in a molar ratio of 0.5:0.25:1, wet-milled with absolute ethanol as a medium, and dried at 950°C for 3 hours to synthesize BaFe 0.5 sn 0.5 o 3 Ceramic blanks.

[0019] BaFe 0.5 sn 0.5 o 3 The ceramic blank is dried by ball milling for the second time, and then a 3% PVA solution is added as a binder, and pressed into a disc with a diameter of 18mm and a thickness of 1-1.4mm under a pressure of 100MPa, and the heating rate is 150℃ / h at 600℃ Keep warm for 2 hours to discharge the binder, then keep warm at 1250°C for 2 hours at a heating rate of 300°C / h, and finally cool to room temperature with the furnace. The ceramic sheet is covered with silver electrodes on both sides.

[0020] Performance tests show that the room temperature resistivity ρ 25 2800Ω·m, B 25 / 85 The value is 4500K. Related data such as figure 1 shown.

Embodiment 2

[0022] with SnO 2 , Fe 2 o 3 , SrCO 3 The raw materials are mixed according to the molar ratio of 0.7:0.15:1, wet-milled with absolute ethanol as the medium, dried and kept at 950°C for 3 hours to synthesize SrFe 0.3 sn 0.7 o 3 Ceramic blanks.

[0023] SrFe 0.3 sn 0.7 o 3 The ceramic blank is dried by ball milling for the second time, and then a 3% PVA solution is added as a binder, and pressed into a disc with a diameter of 18mm and a thickness of 1-1.4mm under a pressure of 100MPa, and the heating rate is 150℃ / h at 600℃ Keep warm for 2 hours to discharge the binder, then keep warm at 1300°C for 2 hours at a heating rate of 300°C / h, and finally cool to room temperature with the furnace. The ceramic sheet is covered with silver electrodes on both sides.

[0024] Performance tests show that the room temperature resistivity ρ 25 1.2×10 4 Ω·m, B 25 / 85 The value is 4400K. Related data such as figure 2 shown.

Embodiment 3

[0026] with SnO 2 , Fe 2 o 3 、BaCO 3 Raw materials are mixed in a molar ratio of 0.8:0.1:1, wet-milled with anhydrous ethanol as a medium, and dried at 1000°C for 6 hours to synthesize BaFe 0.2 sn 0.8 o 3 Ceramic blanks.

[0027] BaFe 0.2 sn 0.8 o 3 Ceramic blank with Sb 2 o 3 The powder is mixed according to a molar ratio of 100:0.1, then ball-milled and dried for the second time, and then a 3% PVA solution is added as a binder, and pressed into a disc with a diameter of 18mm and a thickness of 1-1.4mm under a pressure of 100MPa. Heat at 600°C for 2 hours at a heating rate of 300°C / h to discharge the binder, then hold at 1350°C for 2 hours at a heating rate of 300°C / h, and finally cool to room temperature with the furnace. The ceramic sheet is covered with silver electrodes on both sides.

[0028] Performance tests show that the room temperature resistivity ρ 25 1.65×10 5 Ω·m, B 25 / 85 The value is 5000K. Relevant data such as image 3 shown.

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Abstract

The invention discloses an NTC heat sensitive conducting ceramic material and a method for preparing the same. The method for preparing the NTC heat sensitive conducting ceramic material comprises the following steps: using BaCO3, SrCO3, SnO2 and Fe2O3 as main raw materials, mixing and ball-milling the raw materials, and drying the mixture to obtain a Ba1-ySryFexSn1-xO3 blank which is not doped, or doped singly, or doped compositely for a secondary ball milling; and adopting an ordinary ceramic preparation process. The B value of the NTC heat sensitive conducting ceramic prepared in the invention can reach 5,100K, and the resistivity at room temperature can be reduced to 2,800 omega.m. The NTC heat sensitive conducting ceramic material has simple preparation process and low cost, and the obtained products can be applied to the aspects of temperature measurement, temperature control, automatic gain adjustment, temperature compensation and the like.

Description

technical field [0001] The invention relates to a conductive ceramic material, in particular to an NTC thermosensitive conductive ceramic material and a preparation method thereof. Background technique [0002] NTC thermally sensitive conductive ceramics (Negative Temperature Coefficient Thermistor) are a type of ceramic device whose resistance decreases with the increase of temperature. Existing NTC thermistors are generally made of transition metal oxide ceramic materials, which are the most widely used temperature sensor materials. According to the composition, NTC thermosensitive conductive ceramics can be divided into oxide system and non-oxide system, and based on the structure, it can be spinel type, perovskite type, fluorite type, rutile type, etc. Among them, spinel-type NTC thermosensitive conductive ceramics are the most common type, mainly containing Fe, Mn, Cu, Ni, Co, Cd, Sb, W, rare earth and other elements, Cu, Ni, Co, Cd, W and rare earth The price is very...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/01C04B35/457
Inventor 袁昌来刘心宇杨云杨华斌
Owner GUILIN UNIV OF ELECTRONIC TECH
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