Search

CN-121974680-A - X8R type high-reliability ceramic dielectric material with double-shell design and preparation method and application thereof

CN121974680ACN 121974680 ACN121974680 ACN 121974680ACN-121974680-A

Abstract

The invention discloses an X8R type high-reliability ceramic dielectric material with a double-shell design, and a preparation method and application thereof, and belongs to the technical field of electronic ceramic materials. The ceramic dielectric material takes barium titanate as a main body material, at least one of Y 2 O 3 、Dy 2 O 3 is taken as a first doping agent, and at least one of MgO and MnO 2 is taken as a second doping agent. The preparation method comprises the steps of pre-sintering BaTiO 3 and a first doping agent at high temperature by a two-step sintering method, and then adding a second doping agent for secondary mixing and high-temperature sintering. The method constructs a double-shell structure of tetragonal crystal nucleus, rare earth-rich inner shell layer and Mg/Mn-rich outer shell layer in ceramic grains. The invention reserves the high dielectric property of BaTiO 3 crystal nucleus, utilizes the rare earth-rich inner shell layer to inhibit the long-range migration of oxygen vacancies, optimizes the temperature stability of the Mg/Mn-rich outer shell layer, realizes the cooperative promotion of high dielectric constant (epsilon r > 2200), X8R wide temperature stability (delta C/C 25℃ is less than or equal to +/-15 percent and minus 55-150 ℃), and high breakdown field strength (more than or equal to 6.7 kV/mm), and is suitable for manufacturing MLCC with high dielectric temperature stability and high voltage resistance.

Inventors

  • ZHANG LEI
  • CAI ZHENHAO
  • Huai Wentao
  • XU ZHOUYI
  • Luan Saiwei
  • He huizhan
  • LU JIBAO
  • SUN RONG

Assignees

  • 中国科学院深圳先进技术研究院

Dates

Publication Date
20260505
Application Date
20251226

Claims (10)

  1. 1. The X8R type high-reliability ceramic dielectric material with the double-shell design is characterized by comprising a main body material and a doping modifier, wherein the main body material is BaTiO 3 , the doping modifier comprises a first doping agent, a second doping agent and a sintering aid, the first doping agent is at least one of rare earth element oxides Y 2 O 3 、Dy 2 O 3 , the second doping agent comprises at least one of MgO and MnO 2 , and the sintering aid is at least one of SiO 2 、Cr 2 O 3 ; The content of the main body material is 90.5-92.9 mol% based on the total molar amount of the ceramic dielectric material, and the total addition amount of the doping modifier is 7.1-9.5 mol% based on the total molar amount of the ceramic dielectric material; the ceramic dielectric material has a core-double shell structure, and comprises tetragonal phase barium titanate crystal nucleus, an inner shell layer rich in a first doping agent and an outer shell layer rich in a second doping agent from inside to outside.
  2. 2. The X8R-type high reliability ceramic dielectric material of claim 1, wherein the ceramic dielectric material is based on total molar weight: The total addition amount of the first doping agent is 0.2-1.1 mol%, the content of Y 2 O 3 in the first doping agent is 0.1-1 mol%, and/or the content of Dy 2 O 3 is 0-0.5 mol%; The total addition amount of the second doping agent is 5.1-7.4 mol%, the content of MgO in the second doping agent is 1-5 mol%, and/or the content of MnO 2 is 0-3 mol%; The total addition amount of the sintering aid is 1.3-2.5 mol%, the content of SiO 2 in the sintering aid is 0-2.5 mol%, and/or the content of Cr 2 O 3 is 0-2.5 mol%.
  3. 3. The X8R-type high reliability ceramic dielectric material of claim 1, wherein each component particle size of the first dopant, the second dopant, and the sintering aid is no more than 100 nm.
  4. 4. The X8R-type high reliability ceramic dielectric material according to claim 1, wherein the average grain size of the ceramic dielectric material is 180-250 nm.
  5. 5. The X8R-type high reliability ceramic dielectric material of claim 1, wherein the ceramic dielectric material meets at least two of the following performance indicators: (a) The capacitance change rate delta C/C 25℃ is less than or equal to +/-15% in the temperature range of-55-150 ℃; (b) Room temperature dielectric constant epsilon r > 2200; (c) The breakdown field intensity is more than or equal to 6.7 kV/mm.
  6. 6. The method for preparing the X8R type high-reliability ceramic dielectric material with the double-shell design according to any one of claims 1 to 5, which is characterized by comprising the following steps: (1) The preparation of presintered powder, namely mixing a main material BaTiO 3 and a first doping agent in proportion, performing wet ball milling and drying, performing high-temperature presintered treatment at 800-1000 ℃ in an air atmosphere, and preserving heat for 2 hours to obtain presintered powder; (2) Secondary mixing, namely mixing the presintered powder obtained in the step (1), a second doping agent and a sintering aid in proportion, performing secondary wet ball milling and drying to obtain ceramic dielectric material powder; (3) And (3) forming and sintering, namely granulating and pressing the powder obtained in the step (2), sintering at a high temperature of 1100-1300 ℃ in a reducing atmosphere, preserving heat for 2-4 hours, and cooling along with a furnace to obtain the ceramic dielectric material.
  7. 7. The method according to claim 6, wherein in the step (3), the reducing atmosphere is a mixed gas of H 2 and N 2 .
  8. 8. A multilayer ceramic capacitor characterized in that the dielectric layer comprises the X8R type high-reliability ceramic dielectric material according to any one of claims 1 to 5, and the multilayer ceramic capacitor has a high dielectric constant, high temperature stability X8R and high withstand voltage.
  9. 9. The use of an X8R-type high reliability ceramic dielectric material according to any one of claims 1 to 6 for the manufacture of an electronic component, wherein the electronic component is a multilayer ceramic capacitor.
  10. 10. The use according to claim 9, wherein the multilayer ceramic capacitor has a high dielectric constant, an X8R temperature characteristic and a high withstand voltage characteristic.

Description

X8R type high-reliability ceramic dielectric material with double-shell design and preparation method and application thereof Technical Field The invention relates to the technical field of electronic ceramic materials, in particular to an X8R type high-reliability ceramic dielectric material with a double-shell design, and a preparation method and application thereof. Background Multilayer ceramic capacitors (MLCCs) are widely used in consumer electronics, automotive electronics, and communications devices. Barium titanate (BaTiO 3) based ceramics are the most important dielectric materials for MLCCs. However, pure barium titanate ceramics have sharp dielectric constant peaks near the Curie temperature (about 120 ℃), so that the temperature stability is poor, and the high-end application standards of X7R or X8R (-55-150 ℃) and delta C/C 25℃ is less than or equal to +/-15%) are difficult to meet. In addition, as electronic systems such as 5G communication, high-end servers, electric vehicles and the like develop to high frequency, high speed and high power density, MLCC dielectric materials face more severe application conditions in working temperature, working electric field and reliability. The stability and reliability of BaTiO 3 system under high temperature and strong electric field have become key bottlenecks for limiting the comprehensive performance and service life of MLCC device, namely, on one hand, inherent mutation of dielectric constant near Curie point makes it difficult to meet the use requirement of wide temperature range, and on the other hand, long-range migration of oxygen vacancy causes reduction of insulation resistance, aggravation of dielectric aging and reduction of breakdown strength. Although the 'core-shell' structural design and the multielement co-doping strategy significantly improve the performance of the MLCC dielectric material, the regulation mechanism of the MLCC dielectric material still has inherent limitations, and three key indexes of 'high dielectric constant, wide temperature range stability and high reliability' are difficult to be co-optimized. Although the traditional core-shell strategy stabilizes the dielectric constant temperature change by means of the thermal stability of the shell cubic phase, discrete or discontinuous transition of shell components leads to insufficient regulation of lattice distortion, and effective component gradient and stress field are difficult to construct in an interface region. Meanwhile, the multi-element doping can reduce the concentration of oxygen vacancies through valence compensation, but is limited by competition of doped sites, solid solubility difference and diffusion kinetics constraint, and local element enrichment and even new defects are easily formed on a crystal boundary or a shell layer, so that the insulating capability of a medium is weakened, an interface conductive channel is increased, and early breakdown is possibly induced under a high electric field. In addition, existing methods are mostly limited to local optimization of single structure or defect level, lacking systematic regulation of global correlation between dielectric response, temperature stability and electric field reliability. Therefore, development of a comprehensive strategy capable of synergistically regulating component distribution, lattice strain and defect chemistry on a macroscopic to lattice scale is needed to break through the existing performance bottleneck and realize the overall jump of dielectric properties and reliability of the MLCC dielectric material. Disclosure of Invention The invention aims to provide an X8R type high-reliability ceramic dielectric material with double-shell component gradient and a preparation method thereof, aiming at solving the technical problems that the dielectric constant, the X8R stability in a wide temperature range and the high breakdown field strength of the existing material are difficult to cooperatively optimize, the reliability is insufficient due to uneven doping and migration of oxygen vacancies and the like in the prior art. The invention constructs a special double-shell structure of tetragonal phase core-inner shell-outer shell through a unique pre-sintering two-step process, and the dielectric property and the reliability are cooperatively improved by utilizing component gradient design and defect engineering. To achieve the purpose, the invention adopts the following technical scheme: In a first aspect, the invention provides an X8R type high-reliability ceramic dielectric material with a double-shell design, which comprises a main body material and a doping modifier, wherein the main body material is barium titanate (BaTiO 3), the doping modifier comprises a first doping agent, a second doping agent and a sintering aid, the first doping agent is at least one of rare earth element oxides Y 2O3、Dy2O3, the second doping agent comprises at least one of MgO and MnO 2, and the sintering aid i