A microwave dielectric ceramic material, its preparation method and application

Abstract

The present invention belongs to the technical field of capacitors, and specifically relates to a microwave dielectric ceramic material, a preparation method thereof, and an application thereof. The microwave dielectric ceramic material provided by the present invention uses Ba 1‑x (M1M2) x Nd 2.3‑ y B y Ti 4.5‑z (S1S2) z as a matrix material; uses powder A as a glass sintering aid to reduce the sintering temperature and achieve sintering densification at 1060 - 1120°C; at the same time, under the combined action of powder B, the performance of the microwave dielectric ceramic material is optimized, so that the microwave dielectric ceramic material has a low dielectric loss and ultra-high temperature stability. The dielectric loss of the MLCC prepared from the microwave dielectric ceramic material is less than 2.8×10 ‑4 , and the capacitance temperature coefficient can be controlled within (0 ± 15) ppm / °C in the range of -55°C to 125°C.

Description

Technical Field

[0001] The present invention belongs to the technical field of capacitors, and particularly relates to a microwave dielectric ceramic material, a preparation method thereof and an application thereof. Background Art

[0002] Multi-layer Ceramic Capacitors (MLCCs for short) are widely used in industries such as information engineering, electronic appliances, mobile communications, military, aviation, and oil exploration due to their characteristics of small volume, large capacitance, low loss rate during high-frequency use, suitability for mass production, low price, and high stability. In order to improve the electrochemical performance of MLCC products, currently, the electrodes of MLCC products are mainly prepared from Pd or Ag-Pd, and the sintering temperature of the ceramic materials in MLCCs is mostly 1060 - 1120°C.

[0003] With the development of communication technologies, the application frequency band of radio frequency MLCCs covers an ultra-wide working frequency band from several hundred MHz to several thousand MHz. Microwave dielectric ceramic materials have characteristics such as low loss, good frequency and temperature stability, and good insulation performance, and are the key basic materials for realizing the preparation of radio frequency MLCCs. Currently, however, the sintering temperature of mature high-performance microwave dielectric materials is usually higher than 1300°C, which limits the application of microwave dielectric ceramics in radio frequency MLCC products. In addition, for the temperature-stable radio frequency MLCC products prepared using microwave ceramic materials, the capacitance temperature characteristic parameter is usually C0G (i.e., (0 ± 30) ppm / °C, which can also be called NPO), indicating that within the temperature range of -55°C to 125°C, the capacitance deviation is within the range of (-30 to +30) ppm / °C. At the two temperature points of -55°C and 125°C, the extreme difference between the capacitance temperature coefficients of the material is relatively large (up to 60 ppm / °C at most). As the development speed of electronic components towards high frequency, miniaturization, high reliability and high stability is getting faster and faster, in the application environment of MLCC products, changes in capacitance usually cause relatively large deviations in some functions of the electronic function modules where they are located. Therefore, radio frequency microwave MLCCs with a capacitance temperature characteristic of C0G index can gradually no longer meet the higher requirements for the temperature stability of MLCC products in some high-end products. Therefore, developing a microwave dielectric ceramic material that can achieve co-firing with Ag-Pd electrodes (sintering temperature is 1060°C - 1120°C) and at the same time has ultra-high temperature stability is extremely crucial for developing ultra-high temperature stable and highly reliable MLCC products. Summary of the Invention

[0004] In view of this, the present invention provides a microwave dielectric ceramic material, a preparation method and an application thereof. The microwave dielectric ceramic material provided by the present invention has low dielectric loss and high temperature stability, and can be co-fired with an electrode having a sintering temperature of 1060-1120°C, and can be used to prepare a high-temperature stable and highly reliable MLCC.

[0005] In order to solve the above technical problems, the present invention provides a microwave dielectric ceramic material, which is prepared from raw materials including the following parts by mass:

[0006] 91-96 parts of Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z , 3.95-8 parts of powder A and 0.05-1 part of powder B;

[0007] wherein M1 is Sr and Ca, and the molar ratio of Sr to Ca is 0.5-3:1; M2 is Li and Na, and the molar ratio of Li to Na is 0.5-5:1; B is one or more of Bi, Al and Y; S1 is Si and / or Sn, S2 is Nb and / or Ta; 0.05≤x≤0.15, 0.05≤y≤0.20, 0.02≤z≤0.15;

[0008] The preparation raw materials of the powder A include the following components in parts by mass:

[0009]

[0010] The powder B is two or three of ZrO2, MnO2 and Al2O3.

[0011] Preferably, the Ba 1-x (M 1M 2) x N d 2.3-y B y Ti 4.5-z (S1S2) z is Ba 0.9 (Sr5Ca3Li 0.2 Na 0.4 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.47 (Si 0.5 Sn 0.2 Nb4Ta3) 0.03 、Ba 0.9 (Sr5Ca3Li 0.4 Na 0.2 )0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.9 (Sr5Ca3Li 0.4 Na 0.2 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.94 (Sr5Ca3Li 0.4 Na 0.2 ) 0.06 Nd 2.15 (Bi3Al2Y1) 0.15 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.92 (Sr5Ca2Li 0.1 Na 0.02 ) 0.08 Nd 2.25 (Bi 10 Al2Y1) 0.05 Ti 4.48 (Si1Sn 0.5 Nb6Ta7) 0.02 、Ba 0.88 (Sr 25 Ca8Li 0.6 Na 0.2 ) 0.12 Nd 2.18 (Bi 16 Al1Y1) 0.12 Ti 4.44 (Si2Sn 0.3 Nb8Ta 10 ) 0.06 、Ba 0.94 (Sr 15 Ca 10 Li 0.4 Na 0.2 ) 0.06 Nd 2.12 (Bi 16 Al1Y1) 0.18 Ti 4.4 (Si2Sn 0.3Nb8Ta 10 ) 0.1 、Ba 0.9 (Sr5Ca 10 Li1Na 0.4 ) 0.1 Nd 2.11 (Bi3Al1) 0.19 Ti 4.42 (Si3Sn 0.4 Nb 10 Ta4) 0.08 、Ba 0.93 (Sr5Ca 10 Li1Na 0.4 ) 0.07 Nd 2.1 (Bi3Al1) 0.2 Ti 4.45 (Si3Sn 0.4 Nb 10 Ta4) 0.05 、Ba 0.88 (Sr5Ca 10 Li1Na 0.4 ) 0.12 Nd 2.15 (Bi8Al4Y1) 0.15 Ti 4.35 (Si3Sn 0.4 Nb 10 Ta4) 0.15 、Ba 0.85 (Sr 10 Ca 10 Li 0.4 Na 0.4 ) 0.15 Nd 2.17 (Bi8Al4Y1) 0.13 Ti 4.37 (Si3Sn1 Nb 10 Ta4) 0.13 、Ba 0.94 (Sr 15 Ca5Li1Na 0.2 ) 0.06 Nd 2.17 (Bi8Al4Y1) 0.13 Ti 4.38 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.12 、Ba 0.91 (Sr 15 Ca5Li1Na 0.2 ) 0.09 Nd 2.18 (Bi8Al4Y1)0.12 Ti 4.35 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.15 、Ba 0.92 (Sr 15 Ca5Li1Na 0.2 ) 0.08 Nd 2.18 (Bi8Al4Y1) 0.12 Ti 4.35 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.15 or Ba 0.9 (Sr 15 Ca5Li1Na 0.2 ) 0.1 Nd 2.18 (Bi8Al4Y1) 0.12 Ti 4.35 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.15 。

[0012] Preferably, the raw materials for preparing the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z include the following components in parts by mass:

[0013]

[0014] Preferably, the preparation method of the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z includes the following steps:

[0015] Mix the raw materials according to the dosage ratio and then calcine to obtain the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z ;

[0016] The calcination temperature is 1120 - 1160 °C, and the calcination time is 2 - 3 h.

[0017] Preferably, the preparation method of the powder A includes the following steps:

[0018] Mix the raw materials according to the dosage ratio, and then carry out melting and quenching in sequence to obtain the powder A;

[0019] The temperature of the melting is 1400 - 1450 °C; the quenching is water quenching.

[0020] The present invention also provides a preparation method of the microwave dielectric ceramic material described in the above technical solution, including the following steps:

[0021] Mix Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z , the powder A, the powder B and the binder, and granulate to obtain particulate matter;

[0022] Press and sinter the particulate matter in sequence to obtain the microwave dielectric ceramic material.

[0023] Preferably, the pressure of the pressing is 200 - 300 MPa, and the time of the pressing is 10 - 60 s.

[0024] Preferably, the temperature of the sintering is 1060 - 1120 °C, the time of the sintering is 2 - 3 h, and the heating rate to the sintering temperature is 4.8 - 5.2 °C / min.

[0025] Preferably, the binder is an ethanol solution of polyvinyl butyral or an aqueous solution of polyvinyl alcohol.

[0026] The present invention also provides the application of the microwave dielectric ceramic material described in the above technical solution or the microwave dielectric ceramic material prepared by the preparation method described in the above technical solution in the preparation of multilayer ceramic capacitors.

[0027] The present invention provides a microwave dielectric ceramic material, which is prepared from raw materials including the following mass parts: 91 - 96 parts of Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z, 3.95 - 8 parts of powder A and 0.05 - 1 part of powder B; where M1 is Sr and Ca, and the molar ratio of Sr to Ca is 0.5 - 3:1; M2 is Li and Na, and the molar ratio of Li to Na is 0.5 - 5:1; B is one or more of Bi, Al, and Y; S1 is Si and / or Sn, S2 is Nb and / or Ta; 0.05 ≤ x ≤ 0.15, 0.05 ≤ y ≤ 0.20, 0.02 ≤ z ≤ 0.15; The raw materials for preparing powder A include the following components in parts by mass: 1 - 5 parts of Li2CO3, 0.5 - 3 parts of BaCO3, 25 - 35 parts of CaCO3, 20 - 35 parts of SiO2, and 30 - 50 parts of H3BO3; Powder B is two or three of ZrO2, MnO2, and Al2O3. In the present invention, Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z As a matrix material, it has a tungsten bronze structure similar to perovskite. The [TiO6] octahedrons connected by the vertices form a three-dimensional space network structure, and other ions of different sizes and valence states fill the structural voids of different sizes and shapes. Its occupancy formula can be written as: (A1)2(A2)4(C)4(B1)2(B2)8O 30 , In the present invention, the material is modified at the A1, A2, C positions and the B1, B2 positions simultaneously to fill the vacancies in the crystal structure of the material, improve the crystal order of the material, thereby reducing the dielectric loss of the material and improving the temperature stability of the material. In the present invention, powder A is used as a glass sintering aid. By introducing the glass sintering aid, the matrix material can achieve sintering densification at 1060 - 1120 °C; at the same time, under the combined action of powder B, the performance of the microwave dielectric ceramic material is further optimized, making the microwave dielectric ceramic material have a low dielectric loss and ultra-high temperature stability. The dielectric loss of the MLCC prepared from the microwave dielectric ceramic material is lower than 2.8×10 -4 Some parts will be lower than 1×10 -4 , and the capacitance temperature coefficient can be controlled within (0 ± 15) ppm / °C in the range of -55 °C to 125 °C. Some parts can be controlled within (0 ± 5) ppm / °C. Compared with the traditional C0G material with a capacitance temperature coefficient of (0 ± 30) ppm / °C in the range of -55 °C to 125 °C, the performance advantage in terms of temperature stability is extremely obvious. Description of the Drawings

[0028] Figure 1The physical diagram of an RF MLCC with a 0805 size and a capacitance of 820 pF prepared from the microwave dielectric ceramic material prepared in Example 1, where (a) is the overall physical diagram, (b) is the enlarged view of the end of the MLCC product, and (c) is the enlarged view of the internal structure of the MLCC product. Detailed implementation mode

[0029] The present invention provides a microwave dielectric ceramic material, which is prepared from raw materials including the following parts by mass:

[0030] 91-96 parts of Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z , 3.95-8 parts of powder A and 0.05-1 part of powder B.

[0031] In the present invention, if there is no special description, all raw materials are conventional commercially available products.

[0032] Calculated by parts by mass, the raw materials for preparing the microwave dielectric ceramic material provided by the present invention include 91-96 parts of Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z , preferably 92-95 parts, more preferably 93-94 parts. In the present invention, M1 is Sr and Ca, and the molar ratio of Sr and Ca is 0.5-3.2:1, preferably 1-3:1, more preferably 1.5-1.6:1; M2 is Li and Na, and the molar ratio of Li and Na is 0.5-5:1, preferably 1-3:1, more preferably 2-2.5:1. In the present invention, B is one or more of Bi, Al, and Y, preferably two or three of Bi, Al, and Y, more preferably two elements of Bi and Al or three elements of Bi, Al, and Y. In the present invention, when B is Bi and Al, the molar ratio of Bi and Al is preferably 2-4:1, more preferably 3:1; when B is Bi, Al, and Y, the molar ratio of Bi, Al, and Y is preferably 2-16:1:0.02-1, more preferably 1.5-8:1:0.25-0.5, more preferably 2-5:1:0.5.

[0033] In the present invention, S1 is Si and / or Sn, preferably Si and Sn; when S1 is Si and Sn, the molar ratio of Si to Sn is preferably 2 to 7.5:1, more preferably 3.75:1. In the present invention, S2 is Nb and / or Ta, preferably Nb and Ta; when S2 is Nb and Ta, the molar ratio of Nb to Ta is preferably 0.5 to 8:1, more preferably 0.85 to 6:1, still more preferably 2 to 3:1.

[0034] In the present invention, 0.05 ≤ x ≤ 0.15, 0.05 ≤ y ≤ 0.20, 0.02 ≤ z ≤ 0.15, preferably 0.06 ≤ x ≤ 0.12, 0.10 ≤ y ≤ 0.19, 0.05 ≤ z ≤ 0.13, more preferably 0.08 ≤ x ≤ 0.1, 0.12 ≤ y ≤ 0.15, 0.06 ≤ z ≤ 0.12.

[0035] In the present invention, the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z is preferably Ba 0.9 (Sr5Ca3Li 0.2 Na 0.4 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.47 (Si 0.5 Sn 0.2 Nb4Ta3) 0.03 、Ba 0.9 (Sr5Ca3Li 0.4 Na 0.2 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.9 (Sr5Ca3Li 0.4 Na 0.2 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.94 (Sr5Ca3Li 0.4 Na 0.2 )0.06 Neodymium 2.15 (Bi3Al2Y1) 0.15 Titanium 4.45 (Silicon 0.5 Tin 0.2 Niobium4Tantalum3) 0.05 、Barium 0.92 (Strontium5Calcium2Lithium 0.1 Sodium 0.02 ) 0.08 Neodymium 2.25 (Bismuth 10 Aluminum2Yttrium1) 0.05 Titanium 4.48 (Silicon1Tin 0.5 Niobium6Tantalum7) 0.02 、Barium 0.88 (Strontium 25 Calcium8Lithium 0.6 Sodium 0.2 ) 0.12 Neodymium 2.18 (Bismuth 16 Aluminum1Yttrium1) 0.12 Titanium 4.44 (Silicon2Tin 0.3 Niobium8Tantalum 10 ) 0.06 、Barium 0.94 (Strontium 15 Calcium 10 Lithium 0.4 Sodium 0.2 ) 0.06 Neodymium 2.12 (Bismuth 16 Aluminum1Yttrium1) 0.18 Titanium 4.4 (Silicon2Tin 0.3 Niobium8Tantalum 10 ) 0.1 、Barium 0.9 (Strontium5Calcium 10 Lithium1Sodium 0.4 ) 0.1 Neodymium 2.11 (Bismuth3Aluminum1) 0.19 Titanium 4.42 (Silicon3Tin 0.4 Niobium 10 Tantalum4) 0.08 、Barium 0.93 (Strontium5Calcium 10 Lithium1Sodium 0.4 ) 0.07 Neodymium 2.1 (Bismuth3Aluminum1) 0.2 Titanium 4.45 (Silicon3Tin 0.4 Niobium10 Ta4) 0.05 、Ba 0.88 (Sr5Ca 10 Li1Na 0.4 ) 0.12 Nd 2.15 (Bi8Al4Y1) 0.15 Ti 4.35 (Si3Sn 0.4 Nb 10 Ta4) 0.15 、Ba 0.85 (Sr 10 Ca 10 Li 0.4 Na 0.4 ) 0.15 Nd 2.17 (Bi8Al4Y1) 0.13 Ti 4.37 (Si3Sn1Nb 10 Ta4) 0.13 、Ba 0.94 (Sr 15 Ca5Li1Na 0.2 ) 0.06 Nd 2.17 (Bi8Al4Y1) 0.13 Ti 4.38 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.12 、Ba 0.91 (Sr 15 Ca5Li1Na 0.2 ) 0.09 Nd 2.18 (Bi8Al4Y1) 0.12 Ti 4.35 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.15 、Ba 0.92 (Sr 15 Ca5Li1Na 0.2 ) 0.08 Nd 2.18 (Bi8Al4Y1) 0.12 Ti 4.35 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.15 or Ba 0.9 (Sr 15 Ca5Li1Na 0.2 ) 0.1 Nd2.18 (Bi8Al4Y1) 0.12 Ti 4.35 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.15 , more preferably Ba 0.92 (Sr 15 Ca5Li1Na 0.2 ) 0.08 Nd 2.18 (Bi8Al4Y1) 0.12 Ti 4.35 (Si 1.5 Sn 0.4 Nb 10 Ta8) 0.15 。

[0036] In the present invention, in parts by mass, the raw materials for preparing the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z preferably include 17 - 21 parts of BaCO3, 33 - 40 parts of Nd2O3, 37 - 39 parts of TiO2, 0.5 - 2.5 parts of SrCO3, 0.3 - 1.0 part of CaCO3, 0.02 - 0.05 part of Li2CO3, 0.01 - 0.02 part of Na2CO3, 1 - 8 parts of Bi2O, 0.5 - 2 parts of Al2O3, 0 - 1.5 parts of Y2O3, 0.05 - 0.3 part of SiO2, 0.02 - 0.05 part of SnO2, 0.2 - 0.5 part of Nb2O5 and 0.15 - 0.5 part of Ta2O5.

[0037] In the present invention, the preparation method of the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z preferably includes the following steps:

[0038] Mix the raw materials according to the dosage ratio and then calcine to obtain the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z 。

[0039] In the present invention, the mixing is preferably carried out under ball milling conditions, and the ball milling is preferably wet ball milling. In the present invention, the dispersant used in the wet ball milling is preferably water, and the water is preferably deionized water. In the present invention, the ball-to-material ratio of the ball milling is preferably 2 to 8:1, more preferably 4 to 6:1; the rotation speed of the ball milling is preferably 250 to 450 r / min, more preferably 300 to 350 r / min; the time of the ball milling is preferably 4 to 6 h, more preferably 5 h. In the present invention, the ball milling is preferably carried out in a ball mill. The present invention has no special limitation on the model of the ball mill, and the instruments and equipment well-known to those skilled in the art can be used. By controlling the process parameters of the ball milling, the present invention can further improve the uniform dispersion degree of each raw material.

[0040] In the present invention, after the mixing, it preferably further includes: drying, grinding and sieving the mixed product in sequence. The present invention has no special requirement for the drying, as long as the moisture in the mixture can be removed. In the present invention, the aperture of the sieve mesh used for the sieving is preferably 60 to 100 meshes; the present invention has no special limitation on the grinding, as long as the product with the required particle size can be obtained.

[0041] In the present invention, the temperature of the calcination is preferably 1120 to 1160 °C, more preferably 1140 to 1150 °C; the time of the calcination is preferably 2 to 3 h, more preferably 2.5 h. In the present invention, the calcination is preferably carried out in a sintering furnace.

[0042] In the present invention, during the calcination process, the reaction raw materials undergo a high-temperature solid-phase reaction to obtain Ba with a stable crystal structure 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z 。

[0043] By controlling the content of each raw material component in the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z matrix material, the present invention can effectively change the atomic packing density and the degree of order of the structure in the crystal structure of the compound, thereby affecting the dielectric constant, dielectric loss and temperature coefficient of capacitance of the material, and further improving the dielectric properties.

[0044] Taking Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) zBased on the parts by mass, the raw materials for preparing the microwave dielectric ceramic material provided by the present invention include 3.95 to 8 parts of powder A, preferably 4 to 7.5 parts, and more preferably 5 to 6.2 parts. In the present invention, the raw materials for preparing the powder A include 1 to 5 parts of Li2CO3, 0.5 to 3 parts of BaCO3, 25 to 35 parts of CaCO3, 20 to 35 parts of SiO2, and 30 to 50 parts of H3BO3, preferably 2 to 4 parts of Li2CO3, 1 to 2 parts of BaCO3, 7 to 32 parts of CaCO3, 25 to 31 parts of SiO2, and 33 to 38 parts of H3BO3.

[0045] In the present invention, the addition of Li reduces the softening point of the glass powder (powder A) and increases the surface wetting force between the glass powder and the matrix material; the addition of Ba can, on the one hand, reduce the viscosity of the glass powder and, at the same time, improve the chemical compatibility with the matrix material, effectively reducing the dielectric loss of the material; SiO2, as the framework structure of the glass network former, can realize the long-range disordered structure of the glass frit; B2O3 can form a network with SiO2, playing an obvious role in reducing the temperature; the addition of Ca plays a core crystallization role and can form some low-loss phases after sintering. Through the modification of the matrix and the matching of the corresponding glass powder, the present invention finally obtains a microwave dielectric ceramic material with excellent performance and medium-temperature sintering.

[0046] In the present invention, the preparation method of the powder A preferably includes the following steps:

[0047] Mix the raw materials according to the dosage ratio and then carry out melting and quenching in sequence to obtain the powder A.

[0048] In the present invention, the mixing is preferably carried out under ball milling conditions, and the ball milling is preferably wet ball milling. In the present invention, the dispersant used for the wet ball milling is preferably water, and the water is preferably deionized water. In the present invention, the ball-to-material ratio of the ball milling is preferably 2 to 8:1, more preferably 4 to 6:1; the rotation speed of the ball milling is preferably 250 to 450 r / min, more preferably 300 to 350 r / min; the time of the ball milling is preferably 4 to 6 h, more preferably 4 to 5 h. In the present invention, the ball milling is preferably carried out in a ball mill. The present invention has no special limitation on the model of the ball mill, and any instrument and equipment well-known to those skilled in the art can be used. By controlling the process parameters of the ball milling, the present invention can further improve the uniform dispersion degree of each raw material.

[0049] In the present invention, after the mixing, it preferably further includes: sequentially drying, grinding, and sieving the mixed product. The present invention has no special requirements for the drying, as long as the moisture in the mixture can be removed. In the present invention, the aperture of the sieve used for the sieving is preferably 60 meshes; the present invention has no special limitation on the grinding, as long as the product with the required particle size can be obtained.

[0050] In the present invention, the temperature of the melting is preferably 1400 to 1450 °C, more preferably 1420 to 1430 °C; the time of the melting is preferably 1 to 3 h, more preferably 1.5 to 2 h. In the present invention, the melting is preferably carried out by placing the obtained mixture in a Pt crucible.

[0051] In the present invention, the quenching is water quenching, and the water for the water quenching is preferably deionized water. The present invention preferably directly pours the melt obtained by melting into water for quenching.

[0052] In the present invention, after the quenching, it is preferably further included to successively carry out ball milling, drying and grinding on the quenched product. In the present invention, the ball milling is preferably wet ball milling; the dispersant for the wet ball milling is preferably water, and the water is preferably deionized water. In the present invention, the ball-to-material ratio of the ball milling is preferably 2 to 8:1, more preferably 4 to 6:1; the rotation speed of the ball milling is preferably 250 to 450 r / min, more preferably 300 to 350 r / min; the time of the ball milling is preferably 4 to 6 h, more preferably 4 h. In the present invention, the ball milling is preferably carried out in a ball mill. The present invention has no special limitation on the model of the ball mill, and the instruments and equipment well-known to those skilled in the art can be used. The present invention has no special requirement for the drying, as long as the moisture in the product after ball milling can be removed. In the present invention, the average particle size of the ground product is preferably less than or equal to 100 mesh, and the present invention has no special limitation on the grinding, as long as the product with the required particle size can be obtained.

[0053] In the present invention, as a glass sintering aid, the powder A can maintain excellent electrical properties of the matrix material while ensuring a reduction in the sintering temperature of the matrix material (designed based on the compatibility of chemical elements), so that the microwave dielectric ceramic material still has good dielectric properties after the sintering temperature is reduced.

[0054] Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) zBased on the parts by mass, the raw materials for preparing the microwave dielectric ceramic material provided by the present invention include 0.05 to 1 part of powder B, preferably 0.1 to 0.8 part, and more preferably 0.2 to 0.6 part. In the present invention, the powder B is two or three of ZrO2, MnO2, and Al2O3, preferably a mixture of ZrO2, MnO2, and Al2O3 or a mixture of ZrO2 and Al2O3. In the present invention, when the powder B is ZrO2 and Al2O3, the mass percentage of ZrO2 in the powder B is preferably 10 to 80%, more preferably 20%; the mass percentage of Al2O3 in the powder B is preferably 20 to 90%, more preferably 80%. In the present invention, when the powder B is ZrO2, MnO2, and Al2O3, the mass percentage of ZrO2 in the powder B is preferably 10 to 80%, more preferably 20 to 50%, and even more preferably 30 to 45%; the mass percentage of MnO2 in the powder B is preferably 10 to 50%, more preferably 20 to 40%; the mass percentage of Al2O3 in the powder B is preferably 20 to 90%, more preferably 30 to 80%, and even more preferably 40 to 50%.

[0055] In the present invention, the raw materials for preparing the microwave dielectric ceramic material preferably further include a binder, and the binder is preferably an ethanol solution of polyvinyl butyral (PVB) or an aqueous solution of polyvinyl alcohol (PVA).

[0056] The microwave dielectric ceramic material with medium-temperature sintering provided by the present invention can maintain excellent capacitance temperature coefficient in the range of -55 to 150°C, and the capacitance temperature coefficient can reach (0 ± 5) ppm / °C. Compared with the capacitance temperature coefficient (0 ± 30) ppm / °C of traditional C0G materials in the range of -55 to 125°C, the performance advantage is extremely obvious; at the same time, the microwave dielectric ceramic material provided by the present invention has excellent electrical properties, low dielectric loss, ultra-high temperature stability, high insulation resistance, non-toxic raw materials, and low price, and can be applied to the field of RF MLCC.

[0057] In the present invention, Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) zThe compound is used as the matrix material, and the effective adjustment of the dielectric loss and the temperature coefficient of capacitance of the material is achieved through the control of the components in the compound. At the same time, the matching glass powder A is developed, which reduces the sintering temperature of the material while optimizing the temperature coefficient of capacitance of the material and maintaining a low dielectric loss. Finally, through the synergistic effect of powder B, the overall optimization of the temperature coefficient of capacitance and the dielectric loss of the material is achieved, ensuring that the MLCC prepared from the microwave dielectric ceramic material has ultra-high temperature stability and low dielectric loss. The MLCC product prepared from the microwave dielectric ceramic material provided by the present invention meets the stringent technical requirements such as high-reliability life, temperature shock, and steady-state damp heat.

[0058] The present invention also provides a preparation method of the microwave dielectric ceramic material described in the above technical solution, including the following steps:

[0059] Mix Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z with powder A, powder B and a binder, and granulate to obtain particulate matter;

[0060] Press and sinter the particulate matter in sequence to obtain the microwave dielectric ceramic material.

[0061] In the present invention, Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z is mixed with powder A, powder B and a binder and granulated to obtain particulate matter. In the present invention, the mixing preferably includes the following steps:

[0062] Mix Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z with powder A and powder B for the first time to obtain a first mixture;

[0063] Mix the first mixture and the binder for the second time to obtain a second mixture.

[0064] In the present invention, Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z, Powder A and Powder B are first mixed to obtain a first mixture. In the present invention, the first mixing is preferably carried out under ball milling conditions. In the present invention, the ball-to-material ratio of the ball milling is preferably 2 to 10:1, more preferably 5 to 8:1; the rotation speed of the ball milling is preferably 250 to 450 r / min, more preferably 300 to 350 r / min; the time of the ball milling is preferably 4 to 8 h, more preferably 5 to 6 h. In the present invention, the ball milling is preferably carried out in a ball mill. The present invention has no special limitation on the model of the ball mill, and any instrument and equipment well-known to those skilled in the art can be used. By controlling the process parameters of the ball milling, the present invention can further improve the uniform dispersion degree of each raw material.

[0065] In the present invention, after the first mixing, it is preferably further included that the product after the first mixing is sequentially dried and ground. The present invention has no special requirement for the drying, as long as the moisture in the mixture can be removed. In the present invention, the average particle size of the product after grinding is preferably less than or equal to 100 mesh. The present invention has no special requirement for the grinding, as long as the required particle size can be achieved.

[0066] After obtaining the first mixture, the first mixture and a binder are second mixed in the present invention to obtain a second mixture. In the present invention, the binder is preferably an ethanol solution of polyvinyl butyral or an aqueous solution of polyvinyl alcohol, more preferably an aqueous solution of polyvinyl alcohol. In the present invention, the mass concentration of the ethanol solution of polyvinyl butyral is preferably 4.8 to 5.2%, more preferably 5%. In the present invention, the mass concentration of the aqueous solution of polyvinyl alcohol is preferably 4.8 to 5.2%, more preferably 5%. In the present invention, the binder plays a binding role, and the present invention has no special limitation on the dosage of the binder, and any dosage well-known to those skilled in the art can be used.

[0067] The present invention has no special requirement for the second mixing, as long as it can be mixed evenly.

[0068] The present invention has no special requirement for the granulation, and any conventional method in the art can be used.

[0069] After obtaining the particulate matter, the particulate matter is sequentially pressed and sintered in the present invention to obtain the microwave dielectric ceramic material. In the present invention, the pressure of the pressing is preferably 200 to 300 MPa, more preferably 250 to 280 MPa; the time of the pressing is preferably 10 to 60 s, more preferably 30 to 50 s.

[0070] In the present invention, preferably before sintering, it further includes: degumming the pressed product. In the present invention, the degumming temperature is preferably 520 - 550 °C, more preferably 530 - 540 °C; the degumming time is preferably 2 - 4 h, more preferably 3 h; the rate of heating up to the degumming temperature is preferably 1.8 - 2.2 °C / min, more preferably 2 °C / min. Through degumming in the present invention, the binder in the product can be removed.

[0071] In the present invention, the sintering temperature is preferably 1060 - 1120 °C, more preferably 1090 - 1100 °C; the sintering time is preferably 2 - 3 h, more preferably 2.5 - 3 h; the rate of heating up to the sintering temperature is preferably 4.8 - 5.2 °C / min, more preferably 5 °C / min. In the present invention, the sintering is preferably carried out in a sintering furnace. The present invention has no special limitation on the model of the sintering furnace, and any instrument and equipment well-known to those skilled in the art can be used.

[0072] In the present invention, preferably after sintering, it further includes: cooling the sintered product to obtain a microwave dielectric ceramic material. In the present invention, the temperature after cooling is preferably room temperature, and the temperature of the room temperature is preferably 20 - 35 °C, more preferably 25 - 30 °C. In the present invention, the cooling is preferably furnace cooling.

[0073] The present invention also provides the application of the microwave dielectric ceramic material described in the above technical solution or the microwave dielectric ceramic material prepared by the preparation method described in the above technical solution in the preparation of multilayer ceramic capacitors. In the present invention, the electrode in the multilayer ceramic capacitor is preferably an Ag - Pd electrode, and the mass percentage of Ag in the Ag - Pd electrode is preferably 68 - 72%, more preferably 70%. The present invention has no special limitation on the method for preparing the multilayer ceramic capacitor, and any conventional method in the art can be used.

[0074] In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to examples, but they should not be construed as limiting the protection scope of the present invention.

[0075] Example 1

[0076] Mix BaCO3, Nd2O3, TiO2, SrCO3, CaCO3, Li2CO3, Na2CO3, Bi2O, Al2O3, Y2O3, SiO2, SnO2, Nb2O5 and Ta2O5 according to the dosage ratio under the conditions of wet ball milling with deionized water as the dispersant; wherein the ball-to-material ratio of wet ball milling is 5:1, the rotation speed is 350 r / min, the time is 5 h, and the wet ball milling is carried out in a ball mill; successively dry, grind and sieve the mixed product to obtain a mixture with an average pore size of 60 mesh; calcine the mixture at 1150 °C for 2.5 h to obtain Ba 0.9 (Sr5Ca3Li 0.2 Na 0.4 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.47 (Si 0.5 Sn 0.2 Nb4Ta3) 0.03 ;

[0077] By mass fraction, place 5 parts of Li2CO3, 0.5 part of BaCO3, 25 parts of CaCO3, 29.5 parts of SiO2 and 40 parts of H3BO3 in a ball mill, and carry out wet ball milling for 5 h under the conditions of a ball-to-material ratio of 5:1 and a rotation speed of 300 r / min with deionized water as the dispersant, and then successively dry, grind and sieve to obtain a mixture with an average particle size of 60 mesh; melt the mixture at 1400 °C for 2 h, then pour the molten solution obtained by melting into deionized water for water quenching, and ball mill the product after water quenching (carry out wet ball milling with deionized water as the dispersant, the ball-to-material ratio is 5:1, the rotation speed is 300 r / min, and the time is 4 h), dry and grind to obtain powder A with an average particle size of 60 mesh;

[0078] By mass percentage, use 30% ZrO2, 50% MnO2 and 20% Al2O3 as powder B;

[0079] By mass fraction, 96 parts of Ba 0.9 (Sr5Ca3Li 0.2 Na 0.4 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.47 (Si 0.5 Sn 0.2 Nb4Ta3) 0.03, 3.95 parts of powder A and 0.05 parts of powder B are placed in a ball mill and ball milled for 6 h under the conditions of a ball-to-material ratio of 7:1 and a rotation speed of 300 r / min, and then dried and ground to obtain a first mixture with an average particle size of 100 mesh; the first mixture and an aqueous solution of polyvinyl alcohol with a mass concentration of 5% are mixed and granulated to obtain particulate matter;

[0080] The particulate matter is heated to 530 °C at a heating rate of 2 °C / min and held for 3 h for debinding, and then continuously heated to 1120 °C at a heating rate of 5 °C / min and held for 2.5 h for sintering, and then cooled to 25 °C with the furnace to obtain a microwave dielectric ceramic material.

[0081] Examples 2 to 15

[0082] The microwave dielectric ceramic material is prepared according to the method of Example 1, and the specific material composition and process condition parameters are referred to Tables 1 to 4.

[0083] MLCC products are prepared from the microwave dielectric ceramic material powders prepared in Examples 1 to 15. After a series of complex processes such as batching, casting, printing, laminating, uniform pressing, cutting, degassing, sintering, end coating, end firing, electroplating, etc. according to the MLCC product preparation process, MLCC products that can be used for performance testing are obtained. The performance of the MLCC is detected according to the national standard of capacitors GJB 192, and the results are listed in Table 4.

[0084] Figure 1 is a physical diagram of a 0805-size RF MLCC with a capacitance of 820 pF prepared from the microwave dielectric ceramic material prepared in Example 1, where (a) is the overall physical diagram, (b) is an enlarged view of the end of the MLCC product, and (c) is an enlarged view of the internal structure of the MLCC product.

[0085] Table 1 Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z material composition and calcination temperature

[0086]

[0087]

[0088]

[0089]

[0090]

[0091] Table 2 Composition and preparation conditions of powder A

[0092]

[0093] Table 3 Specific Composition of Powder B

[0094]

[0095]

[0096] Table 4 Raw Material Dosages, Sintering Temperatures and Performance Parameters of Microwave Dielectric Ceramic Materials

[0097]

[0098]

[0099] It can be seen from the results in Table 4 that the MLCC prepared by using the microwave dielectric ceramic material provided by the present invention has ultra-high temperature stability, low dielectric loss and high dielectric constant; it can be used for the research and production of RF MLCC, and the prepared MLCC has excellent performance; the dielectric loss can be lower than 2.8×10 -4 Examples 8, 12 and 14 are lower than 1×10 -4 , and the temperature coefficient of capacitance reaches (0±15) ppm / °C in the range of -55°C to 150°C. Examples 3, 13 and 14 reach (0±5) ppm / °C, and Example 14 is (-4 to +2) ppm / °C.

[0100] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A microwave dielectric ceramic material, characterized in that, Prepared from raw materials including the following parts by mass: 91 to 96 parts of Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z , 3.95 to 8 parts of powder A and 0.05 to 1 part of powder B; where M1 is Sr and Ca, and the molar ratio of Sr to Ca is 0.5 - 3:1; M2 is Li and Na, and the molar ratio of Li to Na is 0.5 - 5:1; B is one or more of Bi, Al, and Y; S1 is Si and / or Sn, S2 is Nb and / or Ta; 0.05 ≤ x ≤ 0.15, 0.05 ≤ y ≤ 0.20, 0.02 ≤ z ≤ 0.15; The raw materials for preparing the powder A include the following components in parts by mass: The powder B is two or three of ZrO2, MnO2, and Al2O3.

2. The microwave dielectric ceramic material according to claim 1, characterized in that, The Ba 1-x (M 1M 2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z is Ba 0.9 (Sr5Ca3Li 0.2 Na 0.4 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.47 (Si 0.5 Sn 0.2 Nb4Ta3) 0.03 、Ba 0.9 (Sr5Ca3Li 0.4 Na 0.2 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.9 (Sr5Ca3Li 0.4 Na 0.2 ) 0.1 Nd 2.2 (Bi2Al1Y1) 0.1 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.94 (Sr5Ca3Li 0.4 Na 0.2 ) 0.06 Nd 2.15 (Bi3Al2Y1) 0.15 Ti 4.45 (Si 0.5 Sn 0.2 Nb4Ta3) 0.05 、Ba 0.92 (Sr5Ca2Li 0.1 Na 0.02 ) 0.08 Nd 2.25 (Bi 10 Al2Y1) 0.05 Ti 4.48 (Si1Sn 0.5 Nb6Ta7) 0.02 、Ba 0.88 (Sr 25 Ca8Li​ 0.6 Na 0.2 ) 0.12 Nd 2.18 (Bi 16 Al1Y1) 0.12 Ti 4.44 (Si2Sn 0.3 Nb8Ta 10 ) 0.06 、Ba 0.94 (Sr 15 Ca 10 Li 0.4 Na 0.2 ) 0.06 Nd 2.12 (Bi 16 Al1Y1) 0.18 Ti 4.4 (Si2Sn 0.3 Nb8Ta 10 ) 0.1 、Ba 0.9 (Sr5Ca 10 Li1Na 0.4 ) 0.1 Nd 2.11 (Bi3Al1) 0.19 Ti 4.42 (Si3Sn 0.4 Nb 10 Ta4) 0.08 、Ba 0.93 (Sr5Ca 10 Li1Na 0.4 ) 0.07 Nd 2.1 (Bi3Al1) 0.2 Ti 4.45 (Si3Sn 0.4 Nb 10 Ta4) 0.05 、Ba 0.88 (Sr5Ca 10 Li1Na 0.4 ) 0.12 Nd 2.15 (Bi8Al4Y1) 0.15 Ti 4.35 (Si3Sn 0.4 Nb 10 Ta4) 0.15 、Ba 0.85 (Sr 10 Ca 10 Li 0.4 Na 0.4 ) 0.15 Nd 2.17 (Bi8Al4Y1) 0.13 The 4.37 (Si3Sn1 Nb 10 Ta4) 0.13 、Ba 0.94 (Sr 15 Ca5Li1Na 0.2 ) 0.06 Nd 2.17 (Bi8Al4Y1) 0.13 The 4.38 (Yes 1.5 Sn 0.4 Nb 10 Ta8) 0.12 、Ba 0.91 (Sr 15 Ca5Li1Na 0.2 ) 0.09 Nd 2.18 (Bi8Al4Y1) 0.12 The 4.35 (Yes 1.5 Sn 0.4 Nb 10 Ta8) 0.15 、Ba 0.92 (Sr 15 Ca5Li1Na 0.2 ) 0.08 Nd 2.18 (Bi8Al4Y1) 0.12 The 4.35 (Yes 1.5 Sn 0.4 Nb 10 Ta8) 0.15 或Ba 0.9 (Sr 15 Ca5Li1Na 0.2 ) 0.1 Nd 2.18 (Bi8Al4Y1) 0.12 The 4.35 (Yes 1.5 Sn 0.4 Nb 10 Ta8) 0.15 。 。 3. The microwave dielectric ceramic material according to claim 1 or 2, characterized in that To prepare the Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z The raw materials include the following components in parts by mass:

4. The microwave dielectric ceramic material according to claim 3, characterized in that, The said Ba 1-x (M1M2) x Nd 2.3- y B y Ti 4.5-z (S1S2) z The preparation method thereof comprises the following steps: Mix the raw materials according to the dosage ratio and then calcine to obtain the described Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z ; The calcination temperature is 1120 - 1160 °C, and the calcination time is 2 - 3 h.

5. The microwave dielectric ceramic material according to claim 1, characterized in that, The preparation method of the powder A includes the following steps: Mix the raw materials according to the dosage ratio, and then carry out melting and water quenching in sequence to obtain the powder A; The melting temperature is 1400 - 1450 °C; the water quenching is water quenching.

6. The preparation method of the microwave dielectric ceramic material according to any one of claims 1 - 5, including the following steps: Mix Ba 1-x (M1M2) x Nd 2.3-y B y Ti 4.5-z (S1S2) z with powder A, powder B and a binder, and granulate to obtain particulate matter; Press and sinter the particulate matter in sequence to obtain the microwave dielectric ceramic material.

7. The preparation method according to claim 6, characterized in that, The pressing pressure is 200 - 300 MPa, and the pressing time is 10 - 60 s.

8. The preparation method according to claim 6, characterized in that, The sintering temperature is 1060 - 1120 °C, the sintering time is 2 - 3 h, and the heating rate to the sintering temperature is 4.8 - 5.2 °C / min.

9. The preparation method according to claim 6, wherein The binder is an ethanol solution of polyvinyl butyral or an aqueous solution of polyvinyl alcohol.

10. The application of the microwave dielectric ceramic material according to any one of claims 1 - 5 or the microwave dielectric ceramic material prepared by the preparation method according to any one of claims 6 - 9 in the preparation of multilayer ceramic capacitors.

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