ZnO-Bi2O3-based low-voltage voltage-sensitive ceramic capable of being sintered at low temperature and preparation method thereof

Abstract

The invention discloses ZnO-Bi2O3-based low-voltage voltage-sensitive ceramic capable of being sintered at a low temperature and a preparation method thereof, and particularly relates to a ZnO-Bi2O3-based voltage-sensitive ceramic material which can be sintered at a low temperature of 900 DEG C and has high nonlinearity and low potential gradient and a device thereof. The material is composed of ZnO, Bi2O3, TiO2, Co2O3, MnO2 and B2O3, the formula comprises 98 mol% of ZnO, 0.5 mol% of Bi2O3, 0.5 mol% of TiO2, 0.5 mol% of Co2O3, 0.5 mol% of MnO2 and x wt% of B2O3, and x is larger than 0 and smaller than or equal to 6. According to the formula, after corresponding raw materials are weighed, the corresponding voltage-sensitive ceramic material is obtained after heat preservation is conducted for 2-5 hours at the temperature of 900 DEG C through a solid-phase synthesis method. When x is equal to 1, the comprehensive performance of the ZnO-Bi2O3-based piezoresistor obtained by the method isas follows: the voltage-sensitive field intensity is 130V / mm, the nonlinear coefficient alpha is up to 40, and the leakage current density JL is equal to 2.5 mu A / mm < 2 >; the ceramic material can beused for preparing a multilayer chip varistor taking pure silver as an inner electrode. In addition, the preparation method disclosed by the invention has the advantages of simple process, low energyconsumption, environmental friendliness and the like.

Description

technical field [0001] The invention relates to pressure-sensitive materials and devices, in particular to a ZnO-based pressure-sensitive ceramic resistor with low pressure-sensitive voltage and relatively high nonlinear coefficient and a preparation method thereof. Background technique [0002] Due to the excellent performance of ZnO varistors, which have the characteristics of high nonlinearity, large flow capacity, good temperature characteristics and fast response characteristics, they can be widely used in chip and circuit protection of information equipment, etc., and the market prospect is very broad. However, the in-line ZnO varistor manufactured by traditional technology cannot be used for low voltage because of its high varistor voltage (≥70V), large size, slow response speed, small flow rate, small electrostatic capacity, and insufficient noise absorption performance. Implementation of effective protection for chips [Xiao Shenggen, Gan Guoyou, Yan Jikang, "A Brief...

AI Technical Summary

Problems solved by technology

The disadvantages of the combination of these two systems mainly include four points: ① Bi, the main material forming the grain boundary layer of the ceramic body, reacts with the electrode Pd to combine and decompose, resulting in expansion and contraction of the volume, resulting in deterioration of the thermomechanical properties of the inner electrode and the ceramic body layer. Mismatch, internal stress, even delamination and cracking, have a certain adverse effect on the electrical properties of the product [Kuo S.T., Tuan W.H., Lao Y.W., et al. Investigation into the interactions between Bi 2 o 3 -doped ZnO and AgPd electrode.J.Eur.Ceram.Soc.,2008,28(13):2557–2562; Kuo S.T.,Tuan W.H.Grain growth behavior ofZnO-based multilayervaristors.J.Eur.Ceram.Soc.,2010 ,30(2):525-530.]

②Because the internal electrode uses expensive metal Pd, the production cost of the material is high, which is more than 3 times higher than that of the pure Ag internal electrode

③The firing temperature of this system is relatively high, generally above 1000°C, which is not conducive to energy saving and consumption reduction [Xu D., Shi L.Y., Wu.A.H., “Microstructure and electrical properties of ZnO-BiO-based varistor ceramics by different sintering processes ", J.Eur.Ceram.Soc.,2009,29[9]:1789-1794.]

④The voltage gradient is higher than 450V / mm, which is not suitable for the production of varistor voltage 5V series products

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