Calcium copper titanate ceramic reduction-oxidizing atmosphere co-sintering method

Abstract

The invention discloses a sintering method for preparing copper calcium titanate CaCu3Ti4O12 (CCTO) ceramic with low dielectric loss and high dielectric constant based on reducing-oxidizing atmospheresynergistic sintering. The invention belongs to the field of ceramic sintering. The following technical schemes are adopted: a CCTO ceramic green body is put into an atmosphere sintering furnace; theceramic green body is subjected to a heating stage I under the air atmosphere, a heat preservation stage I under the air atmosphere, a heating stage II under the air atmosphere, a heat preservation stage II under the atmosphere of introducing reducing mixed gas, a cooling stage I under the condition of introducing non-reducing gas without oxygen, a rapid cooling stage II under the condition of introducing oxygen-rich mixed gas, and a furnace cooling stage III in the atmosphere furnace to obtain the CCTO ceramic sintered body. The dielectric property of the CCTO ceramic obtained through the sintering method in the technical scheme is obviously improved, the dielectric constant reaches up to 5 *10 <4 > at the frequency of 1 kHz, and meanwhile the dielectric loss is lower than 0.02.

Description

technical field [0001] The invention relates to the field of dielectric materials, in particular to a sintering method for copper calcium titanate ceramics with high dielectric constant and low dielectric loss. Background technique [0002] In recent years, the demand for high dielectric constant materials in the field of microelectronics has increased year by year. The perovskite calcium copper titanate CaCu 3 Ti 4 o 12 (CCTO) ceramic materials have received extensive attention from academia and industry. On the one hand, this dielectric ceramic material has an ultra-high dielectric constant (10 4 ~10 5 ), and the high dielectric constant has good thermal stability in a wide temperature range near room temperature; on the other hand, CCTO materials also show strong IV nonlinear characteristics. These superior properties make CCTO ceramic materials have great application prospects in future new electronic devices. However, CCTO ceramics also have relatively high dielec...

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Problems solved by technology

The existing research results show that: appropriate doping elements and doping process can reduce the dielectric loss of CCTO ceramics, but at the same time it will also lead to a decrease in the dielectric constant to a certain extent; or the dielectric constant can basically maintain the original level , but the dielectric loss is not significantly reduced, and the dielectric loss value at 1k Hz is still above 0.05. It is difficult to improve the comprehensive dielectric properties of CCTO ceramic materials, and it is still difficult to meet the application requirements in actual electronic devices.

At the same time, most of the existing conventional sintering methods for CCTO ceramics are carried out in an air atmosphere. Generally, the sintering of CCTO ceramics is completed through the stages of temperature rise, heat preservation, temperature rise, heat preservation, and temperature drop. The dielectric properties of CCTO ceramics obtained by this conventional method The loss value is relatively high, and the dielectric loss at 1 kHz is usually above 0.1, which is difficult to meet the requirements of practical device applications

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