Dielectric powder and method for producing the same

Abstract

To provide a dielectric powder that can be atomized by suppressing grain growth when heated.SOLUTION: A dielectric powder contains a perovskite-type compound containing at least Ca and Zr, and a compound containing P. The dielectric powder has a specific surface area of 5 m2 / g or more and 40 m2 / g or less, and a primary particle diameter of 30 nm or more and 300 nm or less. The primary particle diameter of a Ca compound used to prepare the perovskite-type compound is 20 nm or more and 150 nm or less, and the primary particle diameter of a Zr compound used to prepare the perovskite-type compound is 2 nm or more and 50 nm or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a dielectric powder And its manufacturing method Regarding. [Background technology]

[0002] Electronic components such as multilayer ceramic capacitors are known that are manufactured using dielectric powders. In recent years, electronic components have been becoming smaller in size, and as a result, there has been a demand for the dielectric powders used in manufacturing electronic components to be smaller in size. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-178686 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the grains of the dielectric powder grow due to heat applied during the manufacturing process, making it difficult to further reduce the grain size.

[0005] The present invention solves the above-mentioned problems, and provides a dielectric powder capable of suppressing grain growth when heated and of being atomized. and a method for producing such dielectric powder The purpose is to provide. [Means for solving the problem]

[0006] The dielectric powder of the present invention contains a perovskite type compound containing at least Ca and Zr, and a compound containing P. fruit, Specific surface area is 5m 2 / g or more 40m 2 / g or less, and the primary particle size is 33 nm or more and 260 nm or less, The P is contained in an amount of 0.01 to 10 parts by mol per 100 parts by mol of the Zr. It is characterized by:

[0013] The compound containing P may be a phosphate compound.

[0014] The method for producing a dielectric powder of the present invention is a method for producing a dielectric powder containing a perovskite type compound containing at least Ca and Zr, and a compound containing P, The mixture of the Ca compound containing Ca, the Zr compound containing Zr, and the P compound is heat-treated at a temperature of 700° C. or more and 1500° C. or less. The method is characterized by comprising the steps of: . The dielectric powder has a specific surface area of ​​5 m 2 / g or more 40m 2 / g or less, and a primary particle diameter is 33 nm or more and 260 nm or less, and the P may be contained in an amount of 0.01 molar parts or more and 10 molar parts or less relative to 100 molar parts of the Zr. The method may also include a step of pulverizing the mixture after the heat treatment. Effect of the Invention

[0015] According to the present invention, it is possible to provide a dielectric powder that can be atomized by suppressing grain growth during heating. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The features of the present invention will be described in detail below with reference to embodiments of the present invention.

[0017] The dielectric powder of the present invention satisfies the following requirements (hereinafter, referred to as the requirements of the present invention), that is, contains at least a perovskite type compound containing Ca and Zr, and a compound containing P. The specific surface area is 5m 2 / g or more 40m 2 / g or less, the primary particle size is 33 nm or more and 260 nm or less, and P is contained in an amount of 0.01 molar parts or more and 10 molar parts or less relative to 100 molar parts of Zr. The perovskite type compound containing at least Ca and Zr is, for example, CaZrO3. When the dielectric powder contains a compound containing P, grain growth due to heating can be suppressed.

[0018] In the dielectric powder of the present invention, the specific surface area is 5 m 2 / g or more 40m 2 / g or less, and the primary particle size is 33 nm or more 260 nm or less do. When particles are atomized, the crystallinity of the particles may decrease. However, as will be described later, 2By setting the content to be not more than 1 / g, deterioration of crystallinity can be suppressed.

[0020] The above-mentioned dielectric powder can be produced using, for example, a Ca compound having a primary particle size of 20 nm or more and 150 nm or less, a Zr compound having a primary particle size of 2 nm or more and 50 nm or less, and a P-containing compound.

[0021] The Ca compound is a compound containing Ca, such as at least one of calcium carbonate and calcium hydroxide. The Zr compound is a compound containing Zr, such as at least one of zirconium oxide and zirconium hydroxide. The P compound is, for example, a phosphate compound.

[0022] The dielectric powder of the present invention can be produced by heat-treating a mixture of the above-mentioned Ca compound containing Ca, Zr compound containing Zr, and P compound containing P at a temperature of 700°C to 1500°C, and pulverizing the mixture after the heat treatment.

[0023] The dielectric powder of the present invention can be used in the production of electronic components such as multilayer ceramic capacitors.

[0024] <Example> First, the primary particle diameter is 20 nm to 150 nm and the specific surface area is 7 m 2 / g or more 60m 2 / g or less, and a Ca compound having a primary particle diameter of 2 nm to 50 nm and a specific surface area of ​​10 m 2 / g or more 200m 2 / g or less, and a compound containing P. Here, calcium carbonate was prepared as the Ca compound, and zirconium oxide was prepared as the Zr compound.

[0025] Next, the prepared Ca compound and Zr compound were put into a solvent and dissolved to prepare a slurry. Pure water was used as the solvent. The molar ratio of the Ca compound and the Zr compound put into the solvent (Ca compound / Zr compound) is preferably 0.980 or more and 1.025 or less, more preferably 0.993 or more and 1.014 or less.

[0026] Next, a compound containing P was added to the prepared slurry and mixed in a ball mill, then pulverized in a bead mill and dried at a temperature of 70°C to 300°C while stirring. The compound containing P is a phosphate compound, and ammonium hydrogen phosphate was used here. However, the phosphate compound is not limited to ammonium hydrogen phosphate, and sodium phosphate, calcium phosphate, etc. can also be used.

[0027] The product was then sieved and heat-treated, specifically, sintered at a temperature of 700° C. to 1500° C. If the sintering temperature was less than 700° C., synthesis was insufficient, and if it was higher than 1500° C., grain growth was difficult to suppress.

[0028] The sintered product was then mixed with an aqueous solution to form a slurry, which was then pulverized in a bead mill to obtain a dielectric powder. In this dielectric powder, P is contained in an amount of 0.001 to 10 parts by mole per 100 parts by mole of Zr. If the P content is less than 0.001 parts by mole per 100 parts by mole of Zr, it is difficult to obtain the effect of suppressing grain growth during sintering, and if it is more than 10 parts by mole, the crystallinity is deteriorated, and since too much P is added, zirconia and calcium do not come into contact with each other, making it difficult to obtain calcium zirconate. Therefore, it becomes meaningless as a material for ceramic capacitors.

[0029] Here, more detailed numerical values ​​are added to the method of producing the dielectric powder of sample number 2. First, Ca compound and Zr compound were put into a solvent and dissolved to produce a slurry. Pure water was used as the solvent. The molar ratio of Ca compound and Zr compound put into the solvent (Ca compound / Zr compound) was 1.000. A compound containing P was added to the produced slurry and mixed in a ball mill, then crushed in a bead mill and dried at a temperature of 100°C while stirring. The compound containing P was a phosphoric acid compound, and ammonium hydrogen phosphate was used here. The product was sieved and then fired at a temperature of 1000°C, and the fired product was mixed with an aqueous solution to produce a slurry, and then crushed in a bead mill to obtain a dielectric powder.

[0030] Here, a plurality of types of dielectric powders with different amounts of P added were prepared, and the specific surface area and the half-width of the second peak of CaZrO3 by X-ray diffraction were measured. The specific surface area can be measured, for example, by the flow method or the BET one-point method. The lower the value of the half-width of the second peak of CaZrO3 by X-ray diffraction, the higher the crystallinity. The specific surface area, the average value of the primary particle size, the half-width of the second peak of CaZrO3 by X-ray diffraction, and the amount of P added of the prepared dielectric powders of sample numbers 1 to 15 are shown in Table 1. The amount of P added is the molar amount relative to 100 molar parts of Zr.

[0031] [Table 1]

[0032] In Table 1, sample numbers 2 to 4 are those without an *. 14 The dielectric powder satisfies the requirements of the present invention, and is designated by a * in the sample number. and 15 The dielectric powder in the above does not satisfy the requirements of the present invention.

[0033] In the dielectric powder of sample number 1, which does not contain P and does not satisfy the requirements of the present invention, grain growth proceeds during firing, causing the crystal grains to become coarse.

[0034] In contrast, Sample Nos. 2 to 4, which contain a compound containing P and meet the requirements of the present invention, 14 In the dielectric powder of the present invention, grain growth during firing is suppressed. Therefore, when an electronic component such as a multilayer ceramic capacitor is manufactured using a dielectric powder that satisfies the requirements of the present invention, the dielectric layer can be made thin, and an electronic component with excellent characteristics can be manufactured.

[0035] In addition, the present invention satisfies the requirements. Try The dielectric powders of sample numbers 2 to 14 have a half-width of the second peak of CaZrO3 in X-ray diffraction of less than 1.0, and are highly crystalline. 。

[0036] On the other hand, as shown in Table 1, 2 The dielectric powder of sample number 15, which has a capacitance greater than 1.0 / g, has a half-width of the second peak of CaZrO3 measured by X-ray diffraction greater than 1.0 and has low crystallinity.

[0037] The present invention is not limited to the above-described embodiment, and various applications and modifications are possible within the scope of the present invention.

Claims

1. A perovskite-type compound containing at least Ca and Zr, and a compound containing P, Specific surface area is 5m 2 / g or more 40m 2 / g or less, and the primary particle size is 33 nm or more and 260 nm or less, The P is contained in an amount of 0.01 to 10 parts by mol relative to 100 parts by mol of the Zr, The dielectric powder, wherein the compound containing P is derived from a phosphate compound.

2. A method for producing a dielectric powder containing a perovskite type compound containing at least Ca and Zr and a compound containing P, comprising: The method includes a step of heat-treating a mixture of the Ca compound containing Ca, the Zr compound containing Zr, and a phosphate compound at a temperature of 700° C. or more and 1500° C. or less; The method for producing a dielectric powder, wherein the compound containing P is derived from a phosphate compound.

3. The dielectric powder has a specific surface area of ​​5 m 2 / g or more 40m 2 3. The method for producing a dielectric powder according to claim 2, wherein the Zr content is 0.01 to 10 molar parts relative to 100 molar parts of the Zr, and the primary particle diameter is 33 nm to 260 nm.

4. 4. The method for producing a dielectric powder according to claim 2, further comprising the step of pulverizing the mixture after the heat treatment.

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