Heat preservation device for microwave sintering and microwave sintering method of zinc oxide pressure-sensitive ceramic

Abstract

The invention discloses a heat preservation device for microwave sintering and a microwave sintering method of zinc oxide pressure-sensitive ceramic. The method comprises the following steps: carryingout ball milling on zinc oxide, bismuth oxide, cobaltosic oxide, manganese carbonate, antimony oxide, nickel sesquioxide, titanium dioxide, an aluminum nitrate nonahydrate solution, a dispersing agent and the like, granulating, carrying out dry pressing molding, discharging glue, putting into a heat preservation device, and carrying out microwave sintering to obtain the zinc oxide pressure-sensitive ceramic. The heat preservation device comprises a box body, a high crucible, a short crucible, powder for pressing a ceramic chip green body, an end cover and a thermocouple; the high crucible isstacked on the short crucible; end covers are arranged on the top surface and the bottom surface in the box body; the thermocouple and the high crucible are in connection. The heat preservation deviceis adopted for microwave sintering, the temperature difference between materials and the surrounding environment is reduced, and the phenomena of cracks, deformation and uneven colors are eliminated.Compared with a traditional method, the method of the invention has the advantages that the sintering time is shortened by 50%, volatilization of low-melting-point substances and abnormal growth of crystal grains are reduced, and the performance of the obtained product is better than that of the traditional method.

Description

technical field [0001] The invention belongs to the technical field of electronic ceramics, and in particular relates to a heat preservation device for microwave sintering and a microwave sintering method for zinc oxide pressure-sensitive ceramics. Background technique [0002] Zinc oxide varistor ceramics are mixed with a small amount of bismuth oxide (Bi 2 o 3 ), cobalt oxide (Co 2 o 3 ), manganese carbonate (MnCO 3 ), antimony trioxide (Sb 2 o 3 ), titanium dioxide (TiO 2 ), chromium trioxide (Cr 2 o 3 ), nickel oxide (Ni 2 o 3 ) and other fine electronic ceramic components modified by oxides; it has the advantages of low cost, excellent nonlinear volt-ampere characteristics, fast response time, small leakage current, large flow capacity and excellent surge absorption capacity, etc., and is widely used Used as a transient surge suppressor to protect electronic circuits from abnormal overvoltage damage. [0003] Sintering refers to the transformation of powdery...

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Problems solved by technology

However, due to the different microwave absorption capabilities of different media, microwave sintering has the characteristics of selective heating, so if the uniformity of the sample is not good, the overall heating will not be achieved, resulting in deformation or uneven color of the fired ceramic sheet (Xu Dong et al. Research progress of microwave sintered zinc oxide varistor ceramics [J]. Electric Porcelain Arrester, 2007, 5(219): 25-30.)

[0006] Most microwave sintering furnaces use infrared temperature measurement. This method also has some problems of inaccurate temperature measurement and large heat dissipation in the temperature measurement hole. Many infrared thermometers have too large spots and are often not aligned properly. The temperature measurement of the material makes the temperature measurement inaccurate. Generally, when the temperature rises to 1000 °C, the temperature of the infrared temperature measurement hole is 20-50 °C lower (Dai Suming et al. Sources and analysis of infrared temperature measurement errors [J]. Suzhou Journal of Silk Engineering Institute, 2000,20(1):25-29.)

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