Microwave sintering method for PTC ceramics

A microwave sintering and ceramics technology, which is applied in the field of electronic ceramics manufacturing technology, can solve the problems of immature microwave sintering PTC technology, deformation of PTC ceramic sheets, and no large-scale application, and achieve good compactness, lower sintering temperature, and high yield Effect

Inactive Publication Date: 2009-11-04
付明
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In China, microwave sintering PTC technology is not yet mature, especially without large-scale application
The main reason is that the microwave heating rate is too fast, which makes the sintering temperature of the product uneven, and the fired PTC ceramic sheet is seriously deformed.

Method used

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  • Microwave sintering method for PTC ceramics

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] a. Put the PTC green body 6 into the crucible 3, then put the crucible into the furnace 2, cover the cover plate 1, and then put them into the microwave reaction chamber for sintering. The hole in the middle of the cover plate 1 is a temperature measurement hole for infrared temperature measurement. The outside of the thermal insulation body 2 is an alumina fiber layer 5, which is wound by a thin asbestos rope. Between the furnace 2 and the crucible 3 is a SiC rod 4, which is used as an auxiliary heating material.

[0014] b. The sintering process is: heating from room temperature to 500°C, at a rate of 500°C / hour, and then debinding at a constant temperature for 1 hour to eliminate the organic binder in the PTC green body, from 500 to 1250°C to 600°C The temperature is increased at a rate of 1 / hour, and then kept for 10 minutes for sintering. Afterwards, it is kept at 1100°C for 20 minutes to complete the entire sintering process.

[0015] c. During the sintering process, ...

Embodiment 2

[0018] a. The existing PTC green body 6 is heated to 500°C in a common heating furnace, and the temperature is maintained for 60 minutes to remove the organic binder in the PTC green body. After that, the PTC green body 6 is put into the crucible 3, and then the crucible is put into the furnace 2, covered with the cover plate 1, and then put into the microwave reaction chamber for sintering. The hole in the middle of the cover plate 1 is a temperature measurement hole for infrared temperature measurement. The outside of the furnace 2 is alumina fiber 5, and a SiC rod is evenly placed between the furnace 2 and the crucible 3.

[0019] b. The sintering process is: from room temperature to -1220°C, heating at a rate of 500°C / hour, and then holding for 30 minutes. Afterwards, it is kept at 1100°C for 10 minutes to complete the entire sintering process.

[0020] c. The remaining steps are the same as in Example 1.

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Abstract

The invention provides a microwave sintering method for PTC ceramics, and belongs to the technical field of electronic ceramic manufacturing process. In order to solve the problem that the PTC material has poor microwave absorbing property at a lower temperature, the method designs an assistant heating device, and the device can effectively improve the problem that the PTC green blank has low microwave absorbing efficiency at the temperature below 500 DEG C. In order to solve the problems that the PTC is heated unevenly and is easy to crack, the method designs an automatic rotating device with adjustable speed, and the rotating speed of the device is 5 to 30 revolutions per minute. The method provides a low-temperature insulation sintering process for the PTC: raising the temperature at the speed of 300 to 600 DEG C per hour from the room temperature to 500 DEG C, preserving the heat for 1 hour at 500 DEG C, then raising the temperature at the speed of 500 to 800 DEG C per hour, preserving the heat for 10 to 30 minutes with the high temperature of 1,200 to 1,250 DEG C, and then reducing the temperature to 1,100 DEG C at the speed of 500 to 600 DEG C per hour, and preserving the heat for 10 to 30 minutes at low temperature. The method also provides a process for previously removing glue in a common furnace and then carrying out microwave sintering. In order to avoid the problems that the temperature measurement for a thermoelectric couple is easily interfered under the microwave condition and has large error, the method adopts an infrared temperature gauge to measure the temperature. By using the method, the sintering time can be shortened, the sintering temperature can be reduced, and the electrical energy is greatly saved; and the performance of a product is superior to the performance of the product produced by the prior sintering method.

Description

Technical field [0001] The invention relates to a microwave sintering method of PTC ceramics, and the main content includes the design of a PTC ceramic microwave sintering process and a microwave sintering heat preservation and auxiliary heating device, and belongs to the technical field of electronic ceramic manufacturing technology. Background technique [0002] Microwave sintering technology is a new material preparation technology, which has the advantages of shortening the sintering time, lowering the sintering temperature, improving the performance of sintered products, reducing energy consumption and environmental protection. Microwave processing technology of materials is one of the research hotspots of materials science in recent years. Microwave sintering realizes the heating of the material body through the conversion of energy, while the traditional heating method is to heat the material through the transfer of energy. The microwave heating method has high energy util...

Claims

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Application Information

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IPC IPC(8): C04B35/64C04B35/468
Inventor 付明
Owner 付明
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