CN104446443A - Multilayer ceramic capacitor dielectric material with wide operating temperature range and reparation method thereof - Google Patents

Abstract

The invention discloses a multilayer ceramic capacitor dielectric material with a wide operating temperature range. The multilayer ceramic capacitor dielectric material comprises the following raw materials in a mass ratio: BaTiO3: Bi(Zn0.5Ti0.5)O3: Nb2O5 = 1: 0.5-0.7: 0.02-0.06; the Bi(Zn0.5Ti0.5)O3 comprises the following raw materials in a molar ratio: Bi2O3: ZnO: TiO2 = 1: 1: 1. A preparation method of the multilayer ceramic capacitor dielectric material comprises the following steps: firstly mixing Bi2O2, ZnO and TiO2 in the molar ratio of 1: 1: 1, preburning at 950 DEG C after ball-milling drying, then carrying out secondary ball-milling to obtain Bi(Zn0.5Ti0.5)O3 powder. Sintering is carried out at the temperature of 1130-1190 DEG C, the dielectric constant epsilon r is greater than or equal to 800, the dielectric loss tan delta is less than or equal to 5.5%, and the rate of change of capacitance delta C/C 20 DEG C is less than or equal to +/-15% in the range of -30 to 230 DEG C. The power is uniform in components, is free of pollution in the process, and has a wide application prospect.

Description

Wide operating temperature range medium material for multilayer ceramic capacitors and preparation method thereof

Technical field

The invention belongs to a kind of take composition as the ceramic composition of feature, particularly a kind of BaTiO ₃-Bi (Zn _0.5ti _0.5) O ₃-Nb ₂o ₅medium material for multilayer ceramic capacitors of sound stage width operating temperature range and preparation method thereof.

Background technology

Along with the high speed development of multiple mobile electronic device such as notebook computer, mobile telephone, digital camera, automotive electronics etc., chip electronic component progressively instead of conventional wire type electronic component.Chip multilayer ceramic capacitor (MLCC) is the maximum chip components and parts of current turnout, sales volume, and it electrode materials and ceramic body is replaced parallel connection with multilayer be superimposed together, and burn till an entirety simultaneously.

In recent years, the development trend of MLCC dielectric material is improve its over-all properties always, under the prerequisite ensureing its high reliability, expand its use temperature scope, successively there is the dielectric material meeting EIA (Electronic Industries Associate, International Electro TIA) X7R (operating temperature range is-55 ~ 125 DEG C), X8R (operating temperature range is-55 ~ 150 DEG C), X9R (operating temperature range is-55 ~ 200 DEG C) standard.But, in fields such as aerospace, geological prospecting, automotive electronics, the environment for use of MLCC is harsher, X9R cannot meet service requirements completely, therefore improve the dielectric-temperature stability of barium phthalate base dielectric material and obtain large as far as possible operation temperature area and remain one of current study hotspot, and now the research emphasis of dielectric capacitor manufacturer namely around the research of formula and preparation technology.

Summary of the invention

Object of the present invention, being for meeting the harsher temperature condition of laminated ceramic capacitor environment for use, providing the ceramic capacitor dielectric material that a kind of operating temperature range is wide, Capacitance Shift Rate is less.

The present invention is achieved by following technical solution.

A kind of wide operating temperature range medium material for multilayer ceramic capacitors, raw material composition and mass ratio thereof are:

BaTiO ₃：Bi(Zn _0.5Ti _0.5)O ₃：Nb ₂O ₅＝1：0.5～0.7：0.02～0.06；

Described Bi (Zn _0.5ti _0.5) O ₃raw material composition and mol ratio be Bi ₂o ₃: ZnO:TiO ₂=1:1:1;

The preparation method of this wide operating temperature range medium material for multilayer ceramic capacitors, step is as follows:

(1) by Bi ₂o ₃, ZnO, TiO ₂according to mol ratio 1:1:1 batching, with deionized water mixing and ball milling, Ball-milling Time 4h, ball milling post-drying also in 950 DEG C of pre-burnings, obtains Bi (Zn _0.5ti _0.5) O ₃solid particulate;

(2) by step (1) gained Bi (Zn _0.5ti _0.5) O ₃solid particulate mixes with deionized water, carries out secondary ball milling, Ball-milling Time 5 ~ 10h, after oven dry, crosses 40 mesh sieves, obtains Bi (Zn _0.5ti _0.5) O ₃powder;

(3) by step (2) gained Bi (Zn _0.5ti _0.5) O ₃powder adds BaTiO to ₃in, add Nb simultaneously ₂o ₅, three kinds of constituent masses are than being BaTiO ₃: Bi (Zn _0.5ti _0.5) O ₃: Nb ₂o ₅=1:0.5 ~ 0.7:0.02 ~ 0.06, mixes with deionized water, carries out ball milling, Ball-milling Time 2 ~ 4h;

(4) be the paraffin granulation of 5 ~ 8% by additional mass percent in step (3) gained powder, then cross 1000 holes/cm ³sub-sieve, then be pressed into green compact, forming pressure 6 ~ 10MPa;

(5) mode of burying material is used to sinter on step (4) gained green compact, 550 DEG C of de-waxings are warming up to through 3 ~ 4h, 1130 ~ 1190 DEG C of sintering are risen to, insulation 0.5 ~ 2h, obtained wide operating temperature range medium material for multilayer ceramic capacitors through 1 ~ 3h.

Described step (1), (2), (3) all use QM-3SP4 planetary ball mill to carry out ball milling, drum's speed of rotation 400 revs/min.

Described step (4) adopts 769YP-24B type powder compressing machine to be pressed, and uses Φ 20 mould.

The preferred sintering temperature of described step (5) is 1170 DEG C.

BaTiO of the present invention ₃-Bi (Zn _0.5ti _0.5) O ₃-Nb ₂o ₅wide its sintering temperature of operating temperature range medium material for multilayer ceramic capacitors is 1130 ~ 1190 DEG C, DIELECTRIC CONSTANT ε _r>=800, rate of change of capacitance Δ C/C within the scope of-30 DEG C ~ 230 DEG C _{20 DEG C}≤ ± 15%.It is a kind of very promising system being applied to the wide working temperature medium material for multilayer ceramic capacitors of preparation, and in addition, the powder component that this preparation technology obtains is homogeneous, and process is pollution-free.

Embodiment

The present invention is raw materials used all adopts analytical pure raw material, and specific embodiment is as follows.

Embodiment 1

First by ZnO, Bi ₂o ₃, TiO ₂prepare burden by matter molar percentage 1:1:1, with deionized water mixing and ball milling, use QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 4h post-drying and in 950 DEG C of pre-burnings, obtain Bi (Zn _0.5ti _0.5) O ₃solid particulate; Again by pre-burning gained zinc bismuth titanates Bi (Zn _0.5ti _0.5) O ₃solid particulate carries out secondary ball milling in deionized water, Ball-milling Time 5h, after oven dry, crosses 40 mesh sieves and obtains powder; Again by gained Bi (Zn _0.5ti _0.5) O ₃powder adds BaTiO to ₃in, add Nb simultaneously ₂o ₅, three kinds of constituent masses are than being BaTiO ₃: Bi (Zn _0.5ti _0.5) O ₃: Nb ₂o ₅=1:0.6:0.02, mixes with deionized water, in QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 4h.Again gained is dried in powder and add the paraffin granulation that mass percent is 5%, then cross 1000 holes/cm ³sub-sieve, uses Φ 20 mould, on 769YP-24B type powder compressing machine, is pressed into green compact, forming pressure 6MPa.The mode of burying material is used to carry out green sintering.By the green compact that different Ball-milling Time obtains, point two groups of sintering, are warming up to 550 DEG C of de-waxings through 3h, rise to 1130 DEG C of sintering respectively through 1h, insulation 0.5h, obtained ceramic capacitor dielectric material.The upper and lower surface of resulting product is evenly applied silver slurry, prepare electrode through 840 DEG C of burning infiltrations, the ceramic condenser of obtained wide operating temperature range.

Embodiment 2

First by ZnO, Bi ₂o ₃, TiO ₂prepare burden by matter molar percentage 1:1:1, with deionized water mixing and ball milling, use QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 4h post-drying and in 950 DEG C of pre-burnings, obtain Bi (Zn _0.5ti _0.5) O ₃solid particulate; Again by pre-burning gained zinc bismuth titanates Bi (Zn _0.5ti _0.5) O ₃solid particulate carries out secondary ball milling in deionized water, Ball-milling Time 7h, after oven dry, crosses 40 mesh sieves and obtains powder; Again by gained Bi (Zn _0.5ti _0.5) O ₃powder adds BaTiO to ₃in, add Nb simultaneously ₂o ₅, three kinds of constituent masses are than being BaTiO ₃: Bi (Zn _0.5ti _0.5) O ₃: Nb ₂o ₅=1:0.5:0.06, mixes with deionized water, in QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 3h.Again gained is dried in powder and add the paraffin granulation that mass percent is 7%, then cross 1000 holes/cm ³sub-sieve, uses Φ 20 mould, on 769YP-24B type powder compressing machine, is pressed into green compact, forming pressure 8MPa.The mode of burying material is used to carry out green sintering.By the green compact that different Ball-milling Time obtains, point two groups of sintering, are warming up to 550 DEG C of de-waxings through 3.5h, rise to 1155 DEG C of sintering respectively through 2h, and insulation 1h, can obtain ceramic capacitor dielectric material.The upper and lower surface of resulting product is evenly applied silver slurry, prepare electrode through 840 DEG C of burning infiltrations, the ceramic condenser of obtained wide operating temperature range.

Embodiment 3

First by ZnO, Bi ₂o ₃, TiO ₂prepare burden by matter molar percentage 1:1:1, with deionized water mixing and ball milling, use QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 4h post-drying and in 950 DEG C of pre-burnings, obtain Bi (Zn _0.5ti _0.5) O ₃solid particulate; Again by pre-burning gained zinc bismuth titanates Bi (Zn _0.5ti _0.5) O ₃solid particulate carries out secondary ball milling in deionized water, Ball-milling Time 5h, after oven dry, crosses 40 mesh sieves and obtains powder; Again by gained Bi (Zn _0.5ti _0.5) O ₃powder adds BaTiO to ₃in, add Nb simultaneously ₂o ₅, three kinds of constituent masses are than being BaTiO ₃: Bi (Zn _0.5ti _0.5) O ₃: Nb ₂o ₅=1:0.57:0.024, mixes with deionized water, in QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 4h.Again gained is dried in powder and add the paraffin granulation that mass percent is 7%, then cross 1000 holes/cm ³sub-sieve, uses Φ 20 mould, on 769YP-24B type powder compressing machine, is pressed into green compact, forming pressure 6MPa.The mode of burying material is used to carry out green sintering.By the green compact that different Ball-milling Time obtains, point two groups of sintering, are warming up to 550 DEG C of de-waxings through 3.5h, rise to 1170 DEG C of sintering respectively through 1.5h, and insulation 1h, can obtain ceramic capacitor dielectric material.The upper and lower surface of resulting product is evenly applied silver slurry, prepare electrode through 840 DEG C of burning infiltrations, the ceramic condenser of obtained wide operating temperature range.

Embodiment 4

First by ZnO, Bi ₂o ₃, TiO ₂prepare burden by matter molar percentage 1:1:1, with deionized water mixing and ball milling, use QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 4h post-drying and in 950 DEG C of pre-burnings, obtain Bi (Zn _0.5ti _0.5) O ₃solid particulate; Again by pre-burning gained zinc bismuth titanates Bi (Zn _0.5ti _0.5) O ₃solid particulate carries out secondary ball milling in deionized water, Ball-milling Time 10h, after oven dry, crosses 40 mesh sieves and obtains powder; Again by gained Bi (Zn _0.5ti _0.5) O ₃powder adds BaTiO to ₃in, add Nb simultaneously ₂o ₅, three kinds of constituent masses are than being BaTiO ₃: Bi (Zn _0.5ti _0.5) O ₃: Nb ₂o ₅=1:0.7:0.06, mixes with deionized water, in QM-3SP4 planetary ball mill (drum's speed of rotation 400 revs/min) ball milling 4h.Again gained is dried in powder and add the paraffin granulation that mass percent is 8%, then cross 1000 holes/cm ³sub-sieve, uses Φ 20 mould, on 769YP-24B type powder compressing machine, is pressed into green compact, forming pressure 10MPa.The mode of burying material is used to carry out green sintering.By the green compact that different Ball-milling Time obtains, point two groups of sintering, are warming up to 550 DEG C of de-waxings through 4h, rise to 1190 DEG C of sintering respectively through 3h, and insulation 2h, can obtain ceramic capacitor dielectric material.The upper and lower surface of resulting product is evenly applied silver slurry, prepare electrode through 840 DEG C of burning infiltrations, the ceramic condenser of obtained wide operating temperature range.

Testing method of the present invention and test set as follows: (AC test signals: frequency is 1kHz, voltage is 1V).

(1) test (room temperature 20 DEG C) of specific inductivity and loss

Use electrical capacity C and the loss tan δ of HEWLETT PACKARD 4278A type capacitance tester test sample, and converse the specific inductivity of sample.For wafer capacitance device, conversion relation is as follows:

$\mathrm{\ϵ}=\frac{14.4\×C\×d}{D^2}$

In formula: C-electrical capacity, unit is pF; D, D are respectively thickness, the diameter of sample, unit cm.

(2) test of resistivity

Use the insulation resistance Ri of Agilent 4339B megger test sample, and converse the insulation resistivity ρ v of sample, as follows for wafer type sample reduction formula:

${\mathrm{\ρ}}_v=\begin{array}{c}{R}_i\×\mathrm{\π}\×D^2\\ 4d\end{array}$

In formula: ρ v is the volume specific resistance of sample, unit is Ω cm; Ri is the insulation resistance of sample, and unit is Ω; D, D are respectively thickness, the diameter of sample, and unit is cm.

(3) TC characteristic test

Measure sample is in the electrical capacity of warm area-30 DEG C ~+230 DEG C.Then adopt following formulae discovery volume temperature velocity of variation:

$\frac{\mathrm{\ΔC}}{C}=\frac{C_2-C_1}{C_1}\×100\%$

In formula: C ₁be the electrical capacity at 20 DEG C, unit nF; C ₂for the electrical capacity of arbitrary temp point in-30 DEG C ~ 230 DEG C warm areas, unit nF; Δ C/C is the relative change rate of electrical capacity.

Experiment utilizes GZ-ESPEK high-low temperature chamber and STH-120 type high-temperature cabinet jointly to create the probe temperature environment of-30 DEG C ~+230 DEG C, and adopts HM27002 type electrical condenser C-T/V characteristic dedicated tester and HEWLETT PACKARD 4278A to test display.HM27002 type electrical condenser C-T/V characteristic dedicated tester is set to " interior inclined ", tests from-30 DEG C, then rise to room temperature 20 DEG C, finally rise to+230 DEG C, by the electrical capacity of HP4278A type capacitance measuring tester measure sample in whole warm area.

The dielectric properties test result of above-described embodiment and main technologic parameters refer to table 1.Max| Δ C/C in table 1 _{20 DEG C}| the warm area scope of (%) value is-30 DEG C ~+230 DEG C.

Table 1

Wide operating temperature range medium material for multilayer ceramic capacitors of the present invention, sintering temperature 1130 ~ 1190 DEG C, operating temperature range is-30 DEG C ~+230 DEG C and meets following dielectric properties:

Specific inductivity: ε >=800;

Loss: tan δ≤5.5%;

Temperature profile: Δ C/C ₂₀dEG C≤± 15% ,-30 DEG C ~+230 DEG C.

Claims (4)

1. a wide operating temperature range medium material for multilayer ceramic capacitors, raw material composition and mass ratio thereof are:

BaTiO ₃：Bi(Zn _0.5Ti _0.5)O ₃：Nb ₂O ₅＝1：0.5～0.7：0.02～0.06；

Described Bi (Zn _0.5ti _0.5) O ₃raw material composition and mol ratio be Bi ₂o ₃: ZnO:TiO ₂=1:1:1;

The preparation method of this wide operating temperature range medium material for multilayer ceramic capacitors, step is as follows:

(1) by Bi ₂o ₃, ZnO, TiO ₂according to mol ratio 1:1:1 batching, with deionized water mixing and ball milling, Ball-milling Time 4h, ball milling post-drying also in 950 DEG C of pre-burnings, obtains Bi (Zn _0.5ti _0.5) O ₃solid particulate;

(2) by step (1) gained Bi (Zn _0.5ti _0.5) O ₃solid particulate mixes with deionized water, carries out secondary ball milling, Ball-milling Time 5 ~ 10h, after oven dry, crosses 40 mesh sieves, obtains Bi (Zn _0.5ti _0.5) O ₃powder;

(3) by step (2) gained Bi (Zn _0.5ti _0.5) O ₃powder adds BaTiO to ₃in, add Nb simultaneously ₂o ₅, three kinds of constituent masses are than being BaTiO ₃: Bi (Zn _0.5ti _0.5) O ₃: Nb ₂o ₅=1:0.5 ~ 0.7:0.02 ~ 0.06, mixes with deionized water, carries out ball milling, Ball-milling Time 2 ~ 4h;

(4) be the paraffin granulation of 5 ~ 8% by additional mass percent in step (3) gained powder, then cross 1000 holes/cm ³sub-sieve, then be pressed into green compact, forming pressure 6 ~ 10MPa;

(5) mode of burying material is used to sinter on step (4) gained green compact, 550 DEG C of de-waxings are warming up to through 3 ~ 4h, 1130 ~ 1190 DEG C of sintering are risen to, insulation 0.5 ~ 2h, obtained wide operating temperature range medium material for multilayer ceramic capacitors through 1 ~ 3h.

2. wide operating temperature range medium material for multilayer ceramic capacitors according to claim 1, it is characterized in that, described step (1), (2), (3) all use QM-3SP4 planetary ball mill to carry out ball milling, drum's speed of rotation 400 revs/min.

3. wide operating temperature range medium material for multilayer ceramic capacitors according to claim 1, is characterized in that, described step (4) adopts 769YP-24B type powder compressing machine to be pressed, and uses Φ 20 mould.

4. wide operating temperature range medium material for multilayer ceramic capacitors according to claim 1, is characterized in that, the preferred sintering temperature of described step (5) is 1170 DEG C.