Low-voltage ZnO voltage-sensitive resistance ceramic and preparation method thereof

Abstract

The invention discloses low-voltage ZnO voltage-sensitive resistance ceramic. The low-voltage ZnO voltage-sensitive resistance ceramic is prepared from the following raw materials in parts by weight: 80 to 90 parts of ZnO, 1 to 10 parts of Bi2O3, 0.6 to 1.2 parts of MnO2, 0.1 to 0.8 part of BaCO3, 0.7 to 1.1 parts of Sb2O3, 0.8 to 1.2 parts of Co2O3, 0.9 to 1.5 parts of SiO2, and 0.8 to 1.2 parts of Cr2O3. The invention also discloses a preparation method of the low-voltage ZnO voltage-sensitive resistance ceramic. The preparation method comprises the following steps of using BaCO3 and one part of ZnO to prepare a seed crystal; then, putting the raw materials into a stirring ball mill to perform ball milling, so as to obtain viscous paste; utilizing a spraying and drying technique to spray the viscous paste onto the alloy substrate material, calcining, and demolding, so as to obtain the low-voltage ZnO voltage-sensitive resistance ceramic. The low-voltage ZnO voltage-sensitive resistance ceramic has the advantages that the comprehensive property is excellent, the voltage-sensitive voltage is decreased to 10 to 12V / mm, the residual voltage ratio is 1.190 to 1.20, and the leakage current is less than 1muA / cm<2>.

Description

technical field [0001] The invention relates to the technical field of functional ceramics, in particular to a low-voltage ZnO varistor ceramic and a preparation method thereof. Background technique [0002] Varistor ceramic is a kind of functional ceramic, which refers to a semiconductor ceramic material that has nonlinear volt-ampere characteristics and its resistance decreases sharply with the increase of voltage at a certain temperature and within a certain voltage range. At present, there are mainly four categories of pressure-sensitive ceramics. Among them, zinc oxide varistor ceramics are widely used and have good performance. Since ZnO varistor ceramics exhibit better pressure-sensitive characteristics, the varistor α value (non-linear index) is high (α>60SiC varistor is more than 10 times), with adjustable C value and high flow capacity , so it is widely used. It is widely used in various devices such as power systems, electronic circuits, and household applia...

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Problems solved by technology

However, the equipment required to prepare low-voltage varistor ceramics by this method is expensive, and the process control process is relatively complicated.

For the second method, it can be achieved by increasing the firing temperature or prolonging the holding time, but increasing the firing temperature or prolonging the holding time will cause a large amount of volatilization of zinc oxide and its additives, resulting in loss of nonlinearity or performance degradation of components

In addition, by introducing a grain growth accelerator into the formula, the grain growth can be promoted and the varistor voltage can be significantly reduced, but at the same time, the flow rate is not large due to the uneven development of the grains