Preparation method of titanium dioxide-based ceramic with high electrical resistivity, giant dielectric constant and low loss in reducing atmosphere

Abstract

The invention discloses a preparation method of titanium dioxide-based ceramic with high electrical resistivity, a giant dielectric constant and low loss in a reducing atmosphere. The method comprisesthe steps: adding a trivalent element Al and a pentavalent element Nb with the same molar mass into titanium dioxide at the same time; placing pre-sintered powder in a magnetic field of 3-12 T, to obtain a green body; then sintering the green body at a high temperature in an N2 atmosphere, forming a 'giant defect' dipole in a ceramic, forming more localized electrons, obtaining a giant dielectricceramic, orientating the dipole by the magnetic field under the magnetic field, and limiting the movement of free charges so as to improve the electrical resistivity and reduce the dielectric loss. The prepared ceramic shows excellent temperature stability and frequency stability; the relative dielectric constant is larger than 10<3>, the dielectric loss can reach 0.05-0.1, the electrical resistivity can reach 10<7>-10<9> ohm*cm, and the dielectric ceramic belongs to an environment-friendly electronic material and has practical application value in multilayer electronic element capacitors requiring miniaturization and light weight.

Description

technical field [0001] The invention belongs to the technical field of electronic ceramics and its manufacture, and in particular relates to a preparation method of a titanium dioxide-based dielectric ceramic material with high dielectric constant and good temperature and frequency stability. Background technique [0002] With the miniaturization, integration and intelligence of ceramic capacitors and microwave dielectric components in the microelectronics technology market, multilayer dielectric ceramic capacitors (Multi- The research on layer Ceramic Capacitors (MLCC) has attracted more and more people's attention, especially in high dielectric capacitors, which has a broad application prospect. In order to meet these requirements of electronic material MLCC, a giant dielectric constant (>10 3 ) Inorganic dielectrics have become a challenging topic in the field of materials. [0003] CaCu with perovskite-like structure in common giant dielectric materials 3 Ti 4 o ...

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Problems solved by technology

[0003] CaCu with perovskite-like structure in common giant dielectric materials 3 Ti 4 o 12 (CCTO) ceramics, La 2x Sr x NiO 4 (x=1 / 3 and 1 / 8), NiO, and metal and insulating material composites can be obtained up to 10 5 dielectric constant, but it cannot be co-fired with nickel electrodes in a reducing atmosphere, which limits its practical application in capacitors

In 2013, Liu Yun's research group at the Australian National University reported a new giant dielectric low-loss dielectric material (In 0.5 Nb 0.5 ) x Ti 1-x o 2 , this type of titanium dioxide-based high dielectric (>10 4 )、低损耗(<0.05)的陶瓷也被竞相报道,例如专利公布号CN 104529430A、CN105948743A、 CN106747410A、CN105906340A、CN105732020A、CN107200576A、CN107640970A、 CN108530069A、CN108727013A、CN109133914A,但其对氧分压的敏感性, It cannot be co-fired with nickel electrodes, which limits the application of such materials in MLCC

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