High Temperature Mlcc Ceramic Materials

Multi-layer ceramic capacitor (MLCC) has many advantages, such as compact, small size, high hematocrit, low dielectric loss and low prices. So it is being used in a lot of radio and television, mobile communication, home appliances, medical equipment, etc. civilian electronic equipment products. In addition, in the aerospace, military mobile communications, and military weapons warheads control signal monitoring, and other military electronic equipment, and oil exploration industries it also have a wide range of applications. At present, X7R (-55℃¹25℃,?C/C25℃≤±15%) MLCC is one of the most widely used and studied MLCC products, because of it's high dielectric constant and good temperature stability. But in the engine control unit (ECU), programmed fuel injection (PGFMI), anti-lock braking system (ABS), as a result of harsh conditions, and requirements of its working temperature limit raised to 150℃, So people do a large number of research in X8R(-55℃¹50℃,?C/C25℃≤±15%)ceramic capacitors. But, more and more applications require electronic products in extreme circumstances normal work. For example, the electronic equipment of explore oil and gas reserves may be needed to work at a temperature up to 200℃. This requires the temperature range of MLCC to expand further more. Therefore, the study of high-temperature MLCC is an important direction of the development of multi-layer ceramic capacitors.This paper addresses this issue, respectively BaTiO3, BTBNT (BaTiO3 doped BNT) and BNBT (BNT doped Ba) as the base material to synthesize high-temperature MLCC(-55℃²00℃,?C/C25℃≤±15%)by analysis the impact of doped chemical and process conditions to ceramic. The main results as follows:1. A detailed study of the impact and influence mechanism of Curie temperature of three niobate (MnNb₂O₆, MgNb₂O₆, and ZnNb₂O₆) and the BNT with perovskite ceramic doped BaTiO3; and found they can transfer the Curie temperature of ceramic based BaTiO3, and the effect of BNT is obvious.2. The effects of Nb₂O₅ and MgO on the microstructure and dielectric properties of BaTiO3-Nb-Mg system are investigated in detail. The results showed that the preparation of high-temperature MLCC based on BaTiO₃ was difficult to achieve.3. The effects of Nb₂O₅,ZnO,CaZrO₃,BiNbO₄ and CBS on the microstructure and dielectric properties of BaTiO3 doped by BNT system are investigated in detail. At last, we synthesize high-temperature MLCC based on BTBNT successfully.4. The effects of CaCO3 on the microstructure and dielectric properties of the MLCC based BNBT are investigated in detail. At last, we synthesize high-temperature MLCC based on BNBT successfully.5. The effects of ball milling time on the microstructure and dielectric properties of multi-layer ceramic capacitors based BNBT are investigated in detail. And found ceramic technology has a great influence on the dielectric properties of MLCC.