Middle-high voltage X7R type dielectric ceramic material

Abstract

The invention provides a medium-high voltage X7R type dielectric ceramic material and a preparation method thereof. The dielectric ceramic material comprises main components BaTiO3 powder, R2, R3, R4, R5 and a sintering aid, r1 is an oxide of at least one element selected from Gd, Tb, Dy and Ho, R2 is an oxide of at least one element selected from Gd, Tb, Dy and Ho, R3 is SiO2, R4 is AlN, R5 is GaN, and the sintering aid is V2O5. By adding the wurtzite structure substance, the density of the crystal form is improved, and the breakdown voltage of the X7R type dielectric material can be effectively improved.

Description

Technical Field

[0001] The present application relates to a medium-high voltage X7R type dielectric ceramic material and a preparation method thereof, belonging to the technical field of ceramic capacitor materials. Background Art

[0002] Capacitors are an important type of passive electronic devices, and are indispensable devices in the electronics, communications and information industries. They can store charge, block DC, filter AC waves, provide tuning and oscillation, etc. In recent years, with the widespread use of electronic products, the requirements for capacitors have become increasingly higher, and they are facing the requirements of high breakdown voltage. However, the corresponding materials in the domestic market are gradually unable to meet the development requirements. Therefore, the development of capacitor dielectric materials with higher breakdown voltage and the realization of industrialization are one of the key points of the sustainable development of the domestic electronics industry.

[0003] According to the standards of the Electronic Industries Association (EIA), in X7R ceramic materials: X represents the low temperature limit of the working temperature zone -55°C, 7 represents the high temperature limit of the working temperature zone +125°C, and R represents the rate of change of capacitance at all temperature points in the working temperature zone (within the range of -55°C to +125°C) relative to the room temperature of 25°C, which is less than or equal to ±15%.

[0004] Therefore, the formula adopted in the present invention can effectively improve the breakdown voltage of the X7R type dielectric material by adding wurtzite structure material to increase the crystal density. Summary of the invention

[0005] The present invention aims to provide an X7R ceramic capacitor dielectric material and a preparation method thereof, which overcomes the deficiencies of the prior art and solves the problem of low breakdown voltage of the current ceramic dielectric material, and has a high dielectric constant and low dielectric loss.

[0006] The technical solution of the present invention is: a high breakdown voltage X7R type dielectric ceramic material, the dielectric material is mainly composed of BaTiO3, auxiliary components are R1, R2, R3, R4 and R5, and a sintering aid: wherein the auxiliary components R3, R4 and R5;

[0007] R3 is SiO2; R4 is AlN; R5 is GaN.

[0008] The present invention finds that the wurtzite structure is a hexagonal crystal with cubic symmetry. This crystal is dense and very stable. AlN and GaN both have a wurtzite structure. By adding a small amount of material with this crystal structure, it can be effectively adsorbed on the surface of the main component, thereby reducing the porosity of the material. This structure can greatly improve the breakdown voltage characteristics of the dielectric material.

[0009] As a preferred embodiment of the present invention, R1 is at least one of MnO2 and ZnO; R2 is at least one of Dy2O3 and Ho2O3.

[0010] By selecting the above oxides, the breakdown voltage characteristics of the dielectric material can be further improved.

[0011] As a preferred embodiment of the present invention, the sintering aid is an oxide of V, preferably V2O5.

[0012] As a preferred embodiment of the present invention, the main components are BaTiO3 95-98wt%; R1 0.5-0.8wt%; R2 0.5-0.8wt%; R3 0.1-0.5wt%; R4 0.05-0.1wt%; R5 0.01-0.03wt%; and sintering aid 0.2-0.8wt%.

[0013] The method for preparing the ceramic material is characterized by comprising the following steps:

[0014] Step 1: Prepare the main component BaTiO3 by hydrothermal method;

[0015] Step 2: Mix the auxiliary components R1, R2, R3, R4, R5 and the sintering aid according to the proportion; and calcine;

[0016] Step 3: Mixing, dispersing and drying the calcined powder with the main component to obtain the X7R dielectric material.

[0017] The dielectric ceramic material produced by this formula has dielectric temperature stability that meets the requirements of X7R, a dielectric constant of 2500-2900, and an insulation resistance of >2000, and is suitable for making X7R capacitor products with high breakdown voltage. DETAILED DESCRIPTION

[0018] For ease of understanding of the present invention, the application will be described more fully below with reference to relevant embodiments. The following provides preferred embodiments of the application. However, the application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the application more thorough and comprehensive.

[0019] Example 1

[0020] This embodiment provides a X7R ceramic capacitor dielectric material, including the following raw materials in percentage by weight:

[0021] 96g of BaTiO3, 0.05g of MnO2, 0.3g of ZnO, 0.5g of Dy2O3, 0.1g of SiO2, 0.05g of AlN, 0.01g of GaN, and 0.2g of V2O5.

[0022] The preparation method of the above X7R type dielectric material is as follows:

[0023] Step 1: Prepare the main component BaTiO3 by hydrothermal method;

[0024] Step 2: Mix the auxiliary components R1, R2, R3, R4, R5 and the sintering aid according to the proportion; and calcine at 500-800°C;

[0025] Step 3: Mixing, dispersing and drying the calcined powder with the main component to obtain the X7R dielectric material.

[0026] Example 2

[0027] This embodiment provides a X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 96g of BaTiO3, 0.5g of ZnO, 0.7g of Dy2O3, 0.05g of Ho2O 3， 0.4g SiO2, 0.06g AlN, 0.01g GaN, 0.8g V2O5.

[0028] The preparation method of this embodiment is the same as that of embodiment 1.

[0029] Example 3

[0030] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 97g of BaTiO3, 0.6g of ZnO, 0.8g of Ho2O3, 0.3g of SiO2, 0.06g of AlN, 0.03g of GaN, and 0.3g of V2O5.

[0031] The preparation method of this embodiment is the same as that of embodiment 1.

[0032] Example 4

[0033] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 97g of BaTiO3, 0.25g of MnO2, 0.1g of ZnO, 0.1g of Dy2O3, 0.5g of Ho2O3, 0.2g of SiO2, 0.07g of AlN, 0.03g of GaN, and 0.4g of V2O5.

[0034] The preparation method of this embodiment is the same as that of embodiment 1.

[0035] Example 5

[0036] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 97g of BaTiO3, 0.6g of MnO2, 0.05g of ZnO, 0.6g of Dy2O3, 0.4g of SiO2, 0.07g of AlN, 0.02g of GaN, and 0.5g of V2O5.

[0037] The preparation method of this embodiment is the same as that of embodiment 1.

[0038] Example 6

[0039] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 98g of BaTiO3, 0.7g of ZnO, 0.8g of Dy2O3, 0.3g of SiO2, 0.08g of AlN, 0.02g of GaN, and 0.5g of V2O5.

[0040] The preparation method of this embodiment is the same as that of embodiment 1.

[0041] Example 7

[0042] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 98g of BaTiO3, 0.7g of ZnO, 0.1g of Dy2O3, 0.6g of Ho2O3, 0.5g of SiO2, 0.09g of AlN, 0.01g of GaN, and 0.7g of V2O5.

[0043] The preparation method of this embodiment is the same as that of embodiment 1.

[0044] Example 8

[0045] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 98g of BaTiO3, 0.8g of MnO2, 0.7g of Ho2O3, 0.5g of SiO2, 0.1g of AlN, 0.02g of GaN, and 0.7g of V2O5.

[0046] The preparation method of this embodiment is the same as that of embodiment 1.

[0047] Example 9

[0048] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 95g of BaTiO3, 0.7g of MnO2, 0.7g of Dy2O3, 0.2g of SiO2, 0.1g of AlN, 0.02g of GaN, and 0.6g of V2O5.

[0049] The preparation method of this embodiment is the same as that of embodiment 1.

[0050] Example 10

[0051] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 95g of BaTiO3, 0.8g of ZnO, 0.7g of Dy2O3, 0.1g of SiO2, 0.09g of AlN, 0.03g of GaN, and 0.7g of V2O5.

[0052] The preparation method of this embodiment is the same as that of embodiment 1.

[0053] Comparative Example 1

[0054] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 96g of BaTiO3, 0.8g of ZnO, 0.6g of Dy2O3, 0.4g of SiO2, 0.03g of AlN, 0.01g of GaN, and 0.5g of V2O5.

[0055] The preparation method of this embodiment is the same as that of embodiment 1.

[0056] Comparative Example 2

[0057] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 97g of BaTiO3, 0.7g of MnO2, 0.5g of Dy2O3, 0.3g of SiO2, 0.2g of AlN, 0.02g of GaN, and 0.6g of V2O5.

[0058] The preparation method of this embodiment is the same as that of embodiment 1.

[0059] Comparative Example 3

[0060] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 97g of BaTiO3, 0.6g of MnO2, 0.1g of ZnO, 0.4g of Dy2O3, 0.2g of Ho2O3, 0.2g of SiO2, 0.06g of AlN, and 0.7g of V2O5.

[0061] The preparation method of this embodiment is the same as that of embodiment 1.

[0062] Comparative Example 4

[0063] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 98g of BaTiO3, 0.8g of MnO2, 0.6g of Dy2O3, 0.1g of Ho2O3, 0.4g of SiO2, 0.08g of AlN, 0.05g of GaN, and 0.6g of V2O5.

[0064] The preparation method of this embodiment is the same as that of embodiment 1.

[0065] Comparative Example 5

[0066] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 95g of BaTiO3, 0.1g of MnO2, 0.7g of ZnO, 0.6g of Ho2O3, 0.4g of SiO2, 0.03g of AlN, 0.05g of GaN, and 0.2g of V2O5.

[0067] The preparation method of this embodiment is the same as that of embodiment 1.

[0068] Comparative Example 6

[0069] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 96g of BaTiO3, 0.6g of MnO2, 0.7g of Dy2O3, 0.5g of SiO2, 0.2g of AlN, and 0.4g of V2O5.

[0070] The preparation method of this embodiment is the same as that of embodiment 1.

[0071] Comparative Example 7

[0072] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 98g of BaTiO3, 0.6g of ZnO, 0.5g of Dy2O3, 0.1g of Ho2O3, 0.3g of SiO2, 0.04g of AlN, and 0.4g of V2O5.

[0073] The preparation method of this embodiment is the same as that of embodiment 1.

[0074] Comparative Example 8

[0075] This embodiment provides an X7R ceramic capacitor dielectric material, including the following raw materials in weight percentage: 98g of BaTiO3, 0.3g of MnO2, 0.5g of ZnO, 0.2g of Dy2O3, 0.5g of Ho2O3, 0.3g of SiO2, 0.2g of AlN, 0.04g of GaN, and 0.6g of V2O5.

[0076] The preparation method of this embodiment is the same as that of embodiment 1.

[0077] In the above embodiments, the formula list of each dielectric ceramic material is shown in Table 1.

[0078] Table 1 X7R characteristics MLCC dielectric material composition

[0079]

[0080]

[0081] Performance Testing

[0082] A dispersant is added to the X7R dielectric ceramic material prepared in the above Examples 1-10 and Comparative Examples 1-2 to prepare a slurry, the slurry is passed through a casting machine to form a dielectric green sheet, a nickel alloy electrode is printed on the surface of the sheet by a screen printer, and then the sheets and the printed inner electrodes are stacked according to the designed number of layers; the dielectric films of the printed inner electrodes are alternately stacked to form a laminated sheet; and then a green sheet is formed by isostatic pressing and cutting, and the green sheet is sintered in a reducing atmosphere at 1200°C to form a ceramic body, and after chamfering, external electrodes of Cu alloy are sealed at both ends of the ceramic body, and sintered at a temperature of 900°C in a protective atmosphere to finally obtain a multilayer ceramic capacitor MLCC, the specification of the obtained capacitor is 0805, the thickness of the dielectric layer is 7μm, the number of effective dielectric layers is 108 layers, and then the relevant electrical properties are tested.

[0083] At room temperature 25°C, using an LC bridge, the capacitance C of the capacitor sample was measured at 1.0KHz and 1.0V, and the dielectric constant was calculated based on the thickness of the dielectric layer, the effective electrode area, the screen factor, the number of dielectric layers, and the capacitance C. At a reference temperature of 25°C, using an LC bridge, the loss value of the capacitor sample was measured at 1.0KHz and 1.0V. The maximum breakdown voltage of MLCC was tested using a CJ2671S withstand voltage tester under the conditions of a charging current of <20mA and a voltage application rate of 1000V / 60S. At 140°C, a DC voltage of 300V was applied to the capacitor sample to measure the life time, thereby evaluating the high temperature accelerated life (HALT).

[0084] The test results are shown in Table 2. As can be seen from Table 2, within the required range of the present invention, a dielectric material with excellent dielectric properties and reliability life can be obtained.

[0085] Table 2 Performance parameters of MLCCs prepared in various embodiments and comparative examples

[0086]

[0087]

[0088] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. An X7R type dielectric ceramic material, characterized in that: The dielectric material has BaTiO3 as the main component, R1, R2, R3, R4 and R5 as the auxiliary components, and a sintering aid. composition: Among them, auxiliary components R3, R4 and R5; R3 is SiO2; R4 is AlN; R5 is GaN.

2. The X7R dielectric ceramic material according to claim 1, characterized in that: R1 is an oxide of at least one element selected from the group consisting of Mn, Fe, Zn and Sn.

3. The X7R dielectric ceramic material according to claim 1 or 2, characterized in that: The auxiliary component also includes R2; R2 is an oxide of at least one element selected from Gd, Tb, Dy, and Ho.

4. The dielectric ceramic material according to claim 1, characterized in that The sintering aid is V oxide.

5. The ceramic material according to claims 1 to 4, characterized in that: The main components are BaTiO3, which is 95-98wt%; R1, which is 0.5-0.8wt%; R2 is 0.5-0.8wt%; R3 is 0.1-0.5wt%; R4 is 0.05-0.1wt%; R5 is 0.01-0.03wt%; sintering aid is 0.2-0.8wt%.

6. The method for preparing the X7R ceramic material according to claims 1 to 5, characterized in that: Step 1: Prepare the main component BaTiO3 by hydrothermal method; Step 2: Mix the auxiliary components R1, R2, R3, R4, R5 and the sintering aid according to the proportion; and calcine; Step 3: Mixing, dispersing and drying the calcined powder with the main component to obtain the X7R dielectric material.

7. As claimed in claim 6, characterized in that The preparation method described in step 1 is a hydrothermal method.

8. As claimed in claim 6, characterized in that The calcination temperature in step 2 is 600-800°C.

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