PTC ceramic sintering method

A sintering method and ceramic technology, which is applied in the field of electronic ceramic preparation, can solve problems such as high sensitivity, high reliability, impact resistance, high safety, weakened PTC effect, and increased room temperature resistivity.

Inactive Publication Date: 2013-04-10
GUILIN UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The sintering process currently used in the industry is almost always a one-time heat preservation at a certain temperature, and then directly lowers the temperature. Such a process is difficult to ensure that the density of PTC ceramics reaches 100% of the theoretical densi

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] (1) Put the positive temperature coefficient (PTC) ceramic blank after debinding into the crucible, raise the furnace temperature to 1300°C at a rate of 3°C / min, keep it warm for 0 minutes, and the density of the ceramic will reach 76% of the theoretical density .

[0019] (2) After the step (1) is completed, the furnace temperature is lowered to 1100°C at a cooling rate of 200°C / min, and kept for 120 minutes, and the density of the ceramic reaches 98% of the theoretical density.

[0020] (3) After step (2) is completed, the furnace temperature is raised to 1200°C at a heating rate of 80°C / min, and held for 90 minutes. The density of the ceramic reaches the theoretical density, and then cools with the furnace, and finally obtains a dense structure and uniform grain size. , Ceramics with low room temperature resistivity and high PTC effect.

[0021] figure 1 A schematic diagram of the sintering method is given. After testing, the room temperature resistance reaches 72...

Embodiment 2

[0023] (1) Put the positive temperature coefficient (PTC) ceramic green body after debinding into the crucible, raise the furnace temperature to 1350°C at a heating rate of 5°C / min, keep it warm for 5 minutes, and the density of the ceramic will reach 79% of the theoretical density .

[0024] (2) After step (1) is completed, the furnace temperature is lowered to 1150°C at a cooling rate of 150°C / min and kept for 180 minutes, and the density of the ceramic reaches 98% of the theoretical density.

[0025] (3) After step (2) is completed, the furnace temperature is raised to 1250°C at a heating rate of 100°C / min, and the temperature is kept for 140 minutes. The density of the ceramic reaches the theoretical density, and then cools with the furnace, and finally obtains a compact structure and uniform grain size. , Ceramics with low room temperature resistivity and high PTC effect.

[0026] image 3 A schematic diagram of the sintering method is given. After testing, the room te...

Embodiment 3

[0028] (1) Put the positive temperature coefficient (PTC) ceramic green body after debinding into the crucible, raise the furnace temperature to 1380°C at a heating rate of 7°C / min, keep it warm for 10 minutes, and the density of the ceramic will reach 83% of the theoretical density .

[0029] (2) After step (1) is completed, the furnace temperature is lowered to 1190°C at a cooling rate of 100°C / min, and kept for 240 minutes, and the density of the ceramic reaches 99% of the theoretical density.

[0030] (3) After step (2) is completed, the furnace temperature is raised to 1280°C at a heating rate of 150°C / min, and held for 180 minutes. The density of the ceramic reaches the theoretical density, and then cools with the furnace, and finally obtains a compact structure and uniform grain size. , Ceramics with low room temperature resistivity and high PTC effect.

[0031] Figure 5 A schematic diagram of the sintering method is given. After testing, the room temperature resist...

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Abstract

The invention discloses a PTC (positive temperature coefficient) ceramic sintering method. The method comprises the steps that a PTC ceramic biscuit is put into a crucible, and subjected to quick temperature rise-heat preservation, quick cooling-heat preservation, and further quick temperature rise to slightly high temperature-heat preservation; after the three-step sintering technology, a sintering block body is compacted quickly, and then subjected to furnace cooling; and the density of ceramic reaches the theoretical density. The sintering block body experiences higher sintering temperature, and then is subjected to the heat preservation at a lower temperature by changing the ceramic sintering technology; quick moving of a crystal boundary is inhibited; the sintering block body with fine and uniform crystal grains can be obtained, and further treated at the slightly high temperature; the sintering time can be shortened greatly; and the ceramic which is compact in structure and uniform in grain size, and has lower room temperature resistivity and a higher PTC effect is obtained finally. The characteristics are beneficial for meeting various functional requirements, such as high sensitivity, high reliability, imoact resistance and high safety, of a PTC ceramic sensor.

Description

technical field [0001] The invention relates to a positive temperature coefficient (Positive Temperature Coefficient, PTC for short) ceramic sintering method, which belongs to the field of electronic ceramic preparation. Background technique [0002] Under the influence of the development of the scientific field, information is an object to be detected and controlled. However, the acquisition of information mainly comes from various sensors. Among various sensors, positive temperature coefficient ceramics, referred to as PTC ceramics, are widely used in various fields. With the development of microelectronics technology, the application of PTC ceramic components has been limited, which is manifested in the inability to maintain a high PTC effect while reducing the room temperature resistivity. Therefore, only when the room temperature resistivity is reduced, PTC ceramic components can be applied to overcurrent protection of microelectronic circuits and high current circuits...

Claims

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Application Information

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IPC IPC(8): C04B35/64
Inventor 刘来君郑少英方亮黄延民史丹平
Owner GUILIN UNIVERSITY OF TECHNOLOGY
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