KR0165557B1 - Ceramic composition - Google Patents

Abstract

It is a lead-based perovskite compound that can be sintered at low temperature in the magnetic composition for producing capacitors, has a high dielectric constant, a low temperature change rate of dielectric constant, a small drop in capacity when DC bias is applied, and lead magnesium niobate [Pb (Mg _{1 / 3} component composition consisting of ₃ Nb _2/3 ) O ₃ ], nickel lead niobate [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] and lead titanate [PbTiO ₃ ] or lead magnesium magnesium tungstate [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate [PbTiO ₃ ] and nickel niobate lead [Pb (Ni _1/3 Nb _2/3 ) O ₃ ], manganese niobate as required Lanthanum [La (Mn _2/3 Nb _1/3 ) O ₃ ] is added to the three-component composition or Pb ²⁺ ions present in the three-component composition are substituted with a predetermined amount of La ³⁺ or Ca ²⁺ ions. It relates to a magnetic composition.

Description

Porcelain composition

FIG. 1 shows Pb (Mg _1/3 Nb _2/3 ) O ₃ -Pb (Ni _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ 3 showing the allowable composition range of the main component of the magnetic composition according to the present invention. Component composition diagram.

2 shows Pb (Mg _1/2 W _1/2 ) O ₃ -PbTiO ₃ -Pb (Ni _1/3 Nb _2/3 ) O ₃ 3 showing the allowable composition range of the main component of the magnetic composition according to the present invention. Component composition diagram.

3 is a magnetic composition according to the present invention in which x, y and z are 0.5, 0.3 and 0.2, respectively, and the addition amount of lanthanum manganese niobate (La (Mn _2/3 Nb _1/3 ) O ₃ ) is 0 or 10 mole%. Graph showing temperature change rate of dielectric constant in one embodiment.

4 is a magnetic composition according to the present invention in which x, y and z are 0.2, 0.4 and 0.4, respectively, and the addition amount of lanthanum manganese niobate (La (Mn _2/3 Nb _1/3 ) O ₃ ) is 0 or 10 mole%. Graph showing temperature change rate of dielectric constant in another example.

5 is a graph showing the capacity change rate observed when the DC bias is applied to the multilayer ceramic capacitor with respect to the DC field strength / capacitor layer (measured from Example 3 and Comparative Example 1).

FIG. 6 is a graph showing the capacitance change rate observed for DC field strength / capacitor layer when DC bias is applied to the multilayer ceramic capacitor (measured from Example 4 and Comparative Example 2).

7 is a graph showing the temperature change rate of the dielectric constant of another embodiment of the magnetic composition according to the present invention, wherein x, y and z are 0.5, 0.3 and 0.2 and La ³⁺ substitution amounts are 0, 10 or 30 mole%.

8 is a graph showing the temperature change rate of the dielectric constant of another embodiment of the magnetic composition according to the present invention, wherein x, y and z are 0.2, 0.5 and 0.3, respectively, and La ³⁺ substitution amount is 0, 10 or 30 mole%.

9 is a graph showing the capacity change rate observed when the DC bias is applied to the multilayer ceramic capacitor with respect to the DC field strength / capacitor layer (measured from Example 7 and Comparative Example 3).

FIG. 10 is a graph showing the capacitance change rate observed with respect to the DC field strength / capacitor layer when DC bias is applied to the multilayer ceramic capacitor (measured from Example 8 and Comparative Example 4).

11 is a graph showing the temperature change rate of the dielectric constant of another embodiment of the magnetic composition according to the present invention, wherein x, y and z are 0.2, 0.5 and 0.3 and Ca ²⁺ substitution amounts are 0, 10 or 30 mole%.

FIG. 12 is a graph showing the capacitance change rate observed with respect to the DC field strength / capacitor layer when DC bias is applied to the multilayer ceramic capacitor (measured from Example 10 and Comparative Example 5).

The present invention relates to a ceramic composition, and more particularly, to a magnetic composition having a high dielectric constant, a small temperature change rate of the dielectric constant, and capable of sintering at a low temperature of about 1050 to 1100 ° C or less.

When the multilayer capacitor is formed of the magnetic composition, the magnetic composition should be selected to satisfy the condition that it should have as high a dielectric constant and resistivity as possible. In addition, the dielectric constant decrease due to the temperature change rate, dielectric loss, and DC bias application of the dielectric constant should be as low as possible. Among the magnetic compositions having a high dielectric constant, those mainly composed of barium titanate (BaTiO ₃ ) are well known and already in practical use. However, they require a high sintering temperature. Therefore, in order to improve the temperature characteristics, such as calcium titanate (CaTiO ₃ ) and lead titanate (PbTiO ₃ ) are added, but their sintering temperature is still about 1300 ° or more. For this reason, when a magnetic composition consisting mainly of barium titanate is used to produce a multilayer ceramic capacitor, the material for its internal electrodes is of particular expensive such as precious metals (e.g. platinum, palladium) that can withstand such high sintering temperatures. It is limited to metal. In addition, the dielectric constant obtained in such a dielectric ceramic composition is about 8000 at most. The dielectric constant can be increased, but in this case, the temperature change rate is large. In particular, these magnetic compositions only meet the Y5V properties (-30-85 ° C .; ± 22%, -82%) as defined in the EIA standard.

Although a magnetic material having a small temperature change rate can be produced by a conventional material, the dielectric constant of the resulting magnetic composition is too low to be used as a capacitor material (about 2000).

As mentioned above, in order to reduce the manufacturing cost of multilayer ceramic capacitors, it is necessary to develop a magnetic composition that can be sintered at a low temperature of about 1050 ° C. or lower, and it is possible to use cheaper capacitor internal electrode materials such as mainly composed of silver or nickel. Make it available. Recently, various lead-based composite perovskite compounds sintered at low temperatures and high in dielectric constant have been reported. For example, magnesium niobate [Pb (Mg _1/3 Nb _2/3 ) O ₃ ], nickel niobate [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] and lead titanate [PbTiO ₃ ] The three-component composition of the composition can obtain a dielectric constant of 10000 or more at room temperature (see US Pat. No. 4,712,156). In addition, Japanese Patent Application Laid-Open No. 58-161972 discloses magnesium tungstate lead [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate [PbTiO ₃ ], and nickel niobate lead [Pb (Ni _1/3 Nb). _It is described that a three-component composition consisting of _2/3 ) O ₃ ] can likewise obtain a dielectric constant of 10000 or more. However, these three-component compositions have the drawback that their dielectric constant is greatly affected by temperature. Moreover, the dielectric constant is greatly reduced upon application of a DC bias, and the resulting capacitor is greatly limited in its application.

Accordingly, an object of the present invention is to provide a magnetic composition having the three-component composition, having a high dielectric constant, a low temperature change rate, and a low dielectric constant drop upon application of DC bias.

These and other objects and features of the present invention will become apparent from the following description.

According to a first aspect of the invention, magnesium niobate lead [Pb (Mg _1/3 Nb _1/3 ) O ₃ ], nickel niobate lead [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] and titanic acid A three-component composition consisting of lead [PbTiO ₃ ] was prepared by [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] x [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] y [PbTiO ₃ ] z , x + y + z = 1.0), in the three-component composition diagram, the following composition points

In the main component composition in the line connecting each point of and in the composition range enclosed by said 7 points (a)-(g), lanthanum manganese niobate [La (Mn _2/3 Nb _1/3 ) O ₃ ] as a subsidiary component is 0.01 A magnetic composition added with 10 mole% is provided.

According to a second aspect of the invention, magnesium tungstate lead [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate [PbTiO ₃ ] and nickel niobate lead [Pb (Ni _1/3 Nb _{2 / 3} ) O ₃ ] is a three-component composition consisting of [Pb (Mg _1/2 W _1/2 ) O ₃ ] x [PbTiO ₃ ] y [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] z , x + y + z = 1.0), in the three-component composition diagram, the following composition points

In the main component composition in the line connecting each point of and in the composition range enclosed by said 4 points (h) to (k), lanthanum manganese niobate [La (Mn _2/3 Nb _1/3 ) O ₃ ] as 0.01 is 0.01 A magnetic composition added with 10 mole% is provided.

According to a third aspect of the invention, magnesium niobate lead [Pb (Mg _1/3 Nb _2/3 ) O ₃ ], nickel niobate lead [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] and titanic acid A three-component composition consisting of lead [PbTiO ₃ ] was prepared by [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] x [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] y [PbTiO ₃ ] z , x + y + z = 1.0), in the three-component composition diagram, the following composition points

It comprises a main component material in the line connecting each point of and in the composition range surrounded by the seven points (a) to (g), wherein 0.01 to 30 meol% of lead ions (Pb ²⁺ ) are lanthanum ions (La ³⁺ ) A magnetic composition substituted with is provided.

According to a fourth aspect of the present invention, magnesium tungstate lead [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate [PbTiO ₃ ] and nickel niobate lead [Pb (Ni _1/3 Nb _{2 / 3} ) O ₃ ] is a three-component composition consisting of [Pb (Mg _1/2 W _1/2 ) O ₃ ] x [PbTiO ₃ ] y [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] z , x + y + z = 1.0), in the three-component composition diagram, the following composition points

It comprises a main component material in the form of a line connecting each point of and in the composition range surrounded by the four points (h) to (k), wherein 0.01 to 30 meol% of lead ions (Pb ²⁺ ) are calcium ions (La ³⁺ ) A magnetic composition substituted with is provided.

According to a fifth aspect of the invention, magnesium tungstate lead [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate lead titanate [PbTiO ₃ ] and nickel niobate lead [Pb (Ni _1/3 Nb) _2/3 ) O ₃ ] was added to the composition of [Pb (Mg _1/2 W _1/2 ) O ₃ ] x [PbTiO ₃ ] y [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] z When expressed by (x + y + z = 1.0), in the three-component composition diagram, the following composition points

It comprises a main component material in the form of a line connecting each point of and in the composition range surrounded by the four points (h) to (k), wherein 0.01 to 30 meol% of lead ions (Pb ²⁺ ) are lanthanum ions (Ca ³⁺ ) A magnetic composition substituted with is provided.

Pb (Mg _1/3 Nb _2/3 ) O ₃ -Pb (Ni _1/3 Nb _2/3 ) O ₃ -PbTiO showing the allowable composition range of the main component composition of the magnetic composition according to the first aspect of the present invention the three components of the _third system and the first joseongdo also, Pb (Mg _1/2 W _1/2) showing the permissible composition range of the main component composition of the ceramic composition according to another aspect of the present invention O ₃ -PbTiO ₃ -Pb FIG. 2 is a three-component composition diagram of the (Ni _1/3 Nb _2/3 ) O ₃ system. In Figures 1 and 2, respectively, (a) to (g) or (h) to (k) are the coordinates of the three component compositional diagrams, and the allowable compositional ranges are shown as hatched portions in each figure including a boundary line. It is.

In the first and second aspects of the present invention, the amount of lanthanum manganese niobate La (Mn _2/3 Nb _1/3 ) O ₃ to be added to the magnetic composition is in the range of 0.01 to 10 mole% and preferably 2 to 8 mole% to be. Also in the third and fourth aspects of the invention, the amount of Pb ²⁺ ions to be substituted with La ³⁺ ions is in the range of 0.01 to 30 mole% and preferably 2 to 20 mole%. In addition, the amount of Pb ²⁺ ions to be replaced with Ca ²⁺ ions is in the range of 0.01 to 30 mole% and preferably 2 to 20 mole%.

Hereinafter, the present invention will be described in more detail with reference to the following non-limiting examples, and the effect actually obtained by the present invention will also be described in detail in comparison with the comparative examples.

Example 1

In this embodiment, lead oxide (Pb0), magnesium oxide (MgO), niobium oxide (Nb ₂ O ₅ ), nickel oxide (NiO), titanium oxide (TiO ₂ ), manganese carbonate (MnCO ₃ ) and oxidation as starting materials Lanthanum (La ₂ O ₃ ) is used, and the weight is measured so as to have a compounding ratio shown in Tables 1 to 3, respectively. The weighed starting material is wet milled in a ball mill, mixed, calcined at 750 ° C. to 800 ° C., and the powder is crushed again in a ball mill, filtered and dried, and then placed in an organic binder. By pressing, a circumferential sample having a diameter of approximately 16 mm and a thickness of approximately 10 mm, and a disc shaped sample having approximately 16 mm of diameter and a thickness of approximately 2 mm are produced. The fountain of the required composition is then calcined for 1 hour at a temperature of 1000 to 1100 ℃.

A silver electrode is printed on both sides of the calcined disc sample at 600 ° C., and the temperature change rate of the dielectric constant and dielectric constant is obtained by measuring the capacity at a frequency of 1KHz, voltage 1V r.m.s., and room temperature with a digital LCR meter.

In order to evaluate the mechanical strength of the sample as the bending strength, each sintered circumference is cut into ten rectangular plates having a thickness t of 0.5 mm, a width W of 2 mm, and a length of approximately 13 mm. The distance l between the points was set to 9 mm, and the breaking load Pm (kg) was measured by a three-point bending test, and the bending strength τ (kg / cm 2) was obtained from the equation τ = 3 Pml / 2Wt ² (kg / cm 2). Obtain Each obtained flexural strength is averaged for ten rectangular plates.

Tables 1 to 3 and 4 to 6 show the main components [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] x [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] y [of the magnetic composition thus obtained. The compounding ratios x, y and z of PbTiO ₃ ] z, the amount of minor components added, the dielectric constant, the bending strength, and the rate of change of the dielectric constant measured at −30 ° C. and 85 ° C. are shown. In these tables, an asterisk (*) means that the blending ratio of the main component of the corresponding sample is outside the scope of the present invention. In addition, each permittivity change rate is a value based on the permittivity measured at 20 ° C.

In addition, in order to clarify the effect of the addition of lanthanum manganese niobate [La (Mn _2/3 Nb _1/3 ) O ₃ ], the mixing ratio (x, y, z) is (0.5, 0.3, 0.2) in FIG. The rate of change of the dielectric constant of the magnetic composition in which the amount of lanthanum manganese niobate [La (Mn _2/3 Nb _1/3 ) O ₃ ] is 0 and 10 mole% is shown.

Example 2

Lead starting materials (Pb0), magnesium oxide (MgO), tungsten oxide (WO), niobium oxide (NbO), nickel oxide (NiO), titanium oxide (TiO), manganese carbonate (MnCO) and lanthanum oxide (LaO) Using the weight, each weight is measured so that the compounding ratio shown in Table 7 and Table 8. Thereafter, the same process as used in Example 1 was repeated for the circumferential sample and the disc sample, and the samples were calcined for 1 hour at a temperature of 1000 to 1050 ° C.

In the same manner as in Example 1, the dielectric constant, the temperature change rate of the dielectric constant and the bending strength of each sample are obtained. Table 7, Table 8, Table 9 and Table 10 show the compounding ratios x, y and z of the main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z of the magnetic composition thus obtained, The permittivity, bending strength and rate of change of permittivity measured at −30 ° C. and 85 ° C. are shown. In the above table, an asterisk (*) means that the compounding ratio of the main component of the corresponding sample is outside the limit of the present invention. In addition, each dielectric constant change rate is a value based on the dielectric constant of 20 ℃.

In addition, to clarify the effect of adding lanthanum manganese niobate [La (MnNb) O], FIG. 4 shows that the compounding ratio (x, y, z) is (0.2, 0.4, 0.4) and lanthanum manganese niobate [La (MnNb)]. The temperature change rate of the dielectric constant of the magnetic composition in which the amount of O] is 0 and 10 mole% is shown.

As can be seen from the data of Tables 1 to 6, the porcelain of the present invention in which 0.01 to 10 mole% of [La (MnNb) O] is added as a subcomponent to the [Pb (MgNb) O] -Pb (NiNb) O-PbTiO3 component composition The composition has a small temperature change rate of dielectric constant and a high bending strength, and thus will be useful as a material for producing a multilayer ceramic capacitor.

In addition, as can be seen from the data of Tables 7 to 10, the magnetic composition of the present invention in which 0.01 to 10 mole% of [La (MnNb) O] was added as a subcomponent to the Pb (MgW) O-PbTiO3-Pb (NiNb) O3 component composition The temperature change rate of the dielectric constant is small and the bending strength is large, and thus will be useful as a material for manufacturing a multilayer ceramic capacitor.

Example 3

The blending ratio (x, y, z) of the main component [Pb (MgNb) O] x [Pb (NiNb) O] y [PbTiO] z of the magnetic composition is (0.5, 0.3, 0.2) and lanthanum manganese niobate as a secondary component [La The same process as used in Example 1 is repeated to form a dielectric powder to which (MnNb) O] is added 10 mole%. The dielectric powder thus obtained is dispersed in an organic solvent and kneaded with an organic binder to form a slurry. The slurry thus obtained is formed into a film having a thickness of 40 탆 in accordance with the doctor blade technique used these days. After that, an internal electrode paste is printed on the film according to a conventional screen printing method, and then stamped out, laminated, and hot pressed to form a laminate, and then cut into pieces of a required shape to obtain a green chip for a capacitor. do. The green chip thus obtained is heated to the required temperature so as to remove the binder and fired, and then a silver paste is applied thereto to form an external electrode.

The capacitance of the resulting capacitor is measured at room temperature while a DC bias of 0-50V is applied to the multilayer ceramic capacitor by a digital multimeter. The results thus obtained are shown in FIG.

Example 4

The blending ratio (x, y, z) of the main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z of the magnetic composition is (0.2, 0.4, 0.4) and lanthanum manganese niobate as a secondary component [La The same process as used in Example 1 is repeated to form a dielectric powder to which (MnNb) O] is added 10 mole%.

In addition, in the same manner as used in Example 3, a multilayer ceramic capacitor is manufactured, and its characteristics upon application of DC bias are obtained in the same manner as described in Example 3. The result thus obtained is shown in FIG.

Comparative Example 1

The compounding ratio (x, y, z) of the main component [Pb (MgNb) O] x [Pb (NiNb) O] y) [PbTiO] z is (0.2, 0.6, 0.2) and lanthanum manganese niobate [La (MnNb) O The same procedure as used in Example 3 was repeated except that a composition having no] was used to prepare a capacitor, and its capacity upon application of DC bias was measured in the same manner as in Example 3. The results thus obtained are shown in FIG. 5 together with the results obtained in Example 3. FIG.

Comparative Example 2

The compounding ratio (x, y, z) of the main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z is (0.3, 0.4, 0.3) and Pb The same procedure as used in Example 3 was repeated except that a composition without substitution was used to prepare a capacitor, and its capacity upon application of DC bias was measured in the same manner as in Example 3. The results thus obtained are shown in FIG. 6 together with the results obtained in Example 4. FIG.

The results shown in FIGS. 5 and 6 show that the capacitors obtained from the magnetic composition of the present invention containing lanthanum manganese niobate [La (MnNb) O] used the compositions of Comparative Examples 1 and 2 when DC bias was applied. It clearly shows that the characteristics are superior to that obtained by the capacitor.

Example 5

In this embodiment, lead oxide (PbO), magnesium oxide (MgO), niobium oxide (NbO), nickel oxide (NiO), titanium oxide (TiO), and lanthanum oxide (LaO) were used as starting materials. Each weight is measured so that the compounding ratio shown in Table 13 is obtained. The weighed starting material was wet milled in a ball mill, mixed, calcined at 750 ° C. to 800 ° C., and the obtained powder was pulverized again in a ball mill, filtered and dried, and then placed in an organic binder, pressed and pressed to approximately 16 mm. A disk-shaped sample having a diameter of about 2 mm and a thickness of about 2 mm was prepared. The sample of the required composition is then calcined for 1 hour at a temperature of 1000 to 1100 ℃.

A silver electrode is printed on both sides of the calcined disc sample at 600 ° C., and the capacity and its dielectric loss at a frequency of 1 KHz, voltage 1 V r.m.s., and room temperature are measured with a digital LCR meter to determine the temperature change rate of dielectric constant and dielectric constant. After that, a voltage of 50 V is applied to the sample for 1 minute using an insulation resistance meter to obtain the insulation resistance and obtain the specific resistance.

Tables 11 to 13 and Tables 14 to 16 show the compounding ratios x, y and z, La of the main components [Pb (MgNb) O] x [Pb (NiNb) O] y [PbTiO] z of the magnetic composition thus obtained. The substitution amount (mole%), the specific resistance and the rate of change of permittivity measured at −30 ° C. and 85 ° C. are shown. In these tables, an asterisk (*) means that the blending ratio of the main component of the corresponding sample is outside the scope of the present invention. In addition, each permittivity change rate is a value based on the permittivity measured at 20 ° C.

Also, La To clarify the substitution effect, FIG. 7 shows the compounding ratio (x, y, z) as (0.5, 0.3, 0.2) and La. The temperature change rate of the dielectric constant of the magnetic composition with substitution amounts of 0, 10 and 30 mole% is shown.

Example 6

Lead oxide (Pb0), magnesium oxide (MgO), tungsten oxide (WO), niobium oxide (NbO), nickel oxide (NiO), titanium oxide (TiO) and lanthanum oxide (LaO) were used as starting materials. And the weight is measured so as to have a compounding ratio shown in Table 18. Thereafter, the same process as used in Example 1 was repeated for the circumferential sample and the disc sample, and the samples were calcined for 1 hour at a temperature of 1000 to 1050 ° C.

In the same manner as in Example 1, the dielectric constant, temperature change rate of dielectric constant, dielectric loss and specific resistance of each sample are obtained. Table 17, Table 18, Table 19, and Table 20 show the compounding ratios x, y and z, La of the main components [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z of the magnetic composition thus obtained. The amount of substitution, the resistivity and the rate of change of permittivity measured at −30 ° C. and 85 ° C. are shown.

Also, La To clarify the substitution effect, FIG. 8 shows that the compounding ratio (x, y, z) is (0.2, 0.5, 0.3) and La The temperature change rate of the dielectric constant of the magnetic composition with substitution amounts of 0, 10 and 30 mole% is shown.

As can be seen from the data of Tables 11 to 16, 30 mole% of lead ions (Pb) in the [Pb (MgNb) O] -Pb (NiNb) O-PbTiO3 component composition was used. Lanthanum ion (La The magnetic composition of the present invention substituted with) is an excellent material that can be used to manufacture a multilayer ceramic capacitor having a high specific resistance and a small temperature change rate of dielectric constant.

In addition, as can be seen from the data of Tables 17 to 20, 0.01 to 30 mole% of lead ions (Pb) in the [Pb (MgW) O] —PbTiO—Pb (NiNb) O 3 component composition; Lanthanum ion (La The magnetic composition of the present invention substituted with) is an excellent material that can be used to manufacture a multilayer ceramic capacitor having a high specific resistance and a small temperature change rate of dielectric constant.

Example 7

The compounding ratio (x, y, z) of the main component [Pb (MgNb) O] x [Pb (NiNb) O] y [PbTiO] z of the magnetic composition is (0.5, 0.3, 0.2) and 10 mole% of Pb Ion La The same process as used in Example 5 is repeated to form a dielectric powder substituted with ions. The dielectric powder thus obtained is dispersed in an organic solvent and kneaded with an organic binder to form a slurry. The slurry thus obtained is formed into a film having a thickness of 40 mu m in accordance with the doctor blade technique used these days. After that, the paste for internal electrodes is printed on the film according to a conventional screen printing method, and then steamed out, laminated, and hot pressed to form a laminate, and then in a desired shape to obtain a green chip for a capacitor. Is cut. The green chip thus obtained is heated to the required temperature so as to remove the binder and fired, and then a silver paste is applied thereto to form an external electrode.

The capacitance of the multilayer ceramic capacitor thus obtained is determined at room temperature while a DC bias of 0 to 50 V is applied to the multilayer ceramic capacitor by a digital multimeter. The result thus obtained is shown in FIG.

Example 8

The compounding ratio (x, y, z) of the main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z of the magnetic composition is (0.2, 0.5, 0.3) and 10 mole% of Pb The same process as used in Example 5 is repeated to form an ion-substituted dielectric powder.

In addition, in the same manner as used in Example 7, a multilayer ceramic capacitor was manufactured, and its characteristics upon application of DC bias were measured in the same manner as described in Example 7. The result thus obtained is shown in FIG.

Comparative Example 3

The compounding ratio (x, y, z) of the main component [Pb (MgNb) O] x [Pb (NiNb) O] y [PbTiO] z is (0.2, 0.6, 0.2) and La Except for the absence of substitution, the same procedure as that used in Example 7 was repeated to produce a capacitor, and the capacity at the time of applying the DC bias was measured in the same manner as in Example 7. The results thus obtained are shown in FIG. 9 together with the results obtained in Example 7. FIG.

Comparative Example 4

The compounding ratio (x, y, z) of the main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z is (0.3, 0.4, 0.3) and Pb The same procedure as used in Example 7 was repeated except that a composition without substitution was used to make a capacitor, and the capacity at the time of applying the DC bias was measured in the same manner as in Example 7. The results thus obtained are shown in FIG. 10 along with the results obtained in Example 8. FIG.

The results shown in FIGS. 9 and 10 show lead ions (Pb). Lanthanum ion (La It is clearly shown that the capacitor obtained from the magnetic composition of the present invention substituted with) has superior characteristics than the capacitor obtained using the compositions of Comparative Examples 3 and 4 when DC bias is applied.

Example 9

Lead oxide (PbO), tungsten oxide (WO) magnesium oxide (MgO), niobium oxide (NbO), nickel oxide (NiO), titanium oxide (TiO) and calcium oxide (CaCO) were used as starting materials. Each weight is measured so that the compounding ratio shown in Table 22 is obtained. The weighed starting material is wet milled in a ball mill, mixed, calcined at 800 ° C. to 850 ° C., and the powder thus obtained is pulverized again in a ball mill, filtered and dried, and then placed in an organic binder, pressed, and pressed. A cylindrical sample having a diameter of approximately 16 mm and a thickness of approximately 10 mm and two disc shaped samples having a diameter of approximately 16 mm and a thickness of approximately 2 mm were produced. The sample of the required composition is then calcined for 1 hour at a temperature of 950 to 1050 ℃. A silver electrode is printed on both sides of the calcined disc sample at 600 ° C., and the capacity and its dielectric loss at a frequency of 1 KHz, voltage 1 V r.m.s., and room temperature are measured with a digital LCR meter to determine the temperature change rate of dielectric constant and dielectric constant.

Tables 21 to 24 show the compounding ratios x, y and z, Ca of the main components [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z of the magnetic composition thus obtained. The substitution amount, the dielectric constant at room temperature, the dielectric loss, and the rate of change of the dielectric constant obtained at −30 ° C. and 85 ° C. (dielectric constant at 20 ° C. as reference) are shown. In these tables, the asterisk (*) is Ca The substitution amount means outside the range defined in the present invention, and double asterisk (**) means that the blending ratio of the main component of the corresponding sample is outside the range defined in the present invention.

Also Ca In order to clarify the substitution effect, in FIG. 11, the compounding ratio (x, y, z) is (0.2, 0.5, 0.3) and Ca The temperature change rate of the dielectric constant of the magnetic composition with substitution amounts of 0, 10 and 30 mole% is shown.

As can be seen from the data of Tables 21 to 24, in a three-component composition consisting of Pb (MgW) O-PbTiO-Pb (NiNb) O, 0.01-30 mole% Pb Ions to calcium ions (Ca The magnetic composition of the present invention substituted with) has a high dielectric constant and a small temperature change rate of the dielectric constant, and has Y5U characteristics (-30 to 85 ° C; ± 22%, -56%) or Y5T characteristics (-30). To 85 ° C .; ± 22%, −33%). In addition, the magnetic composition of the present invention can be sintered at a low temperature of 1050 ° C. or lower, so when used in forming a multilayer ceramic capacitor, an inexpensive silver palladium alloy can be used to form the internal electrode thereof.

Example 10

The compounding ratio (x, y, z) of the main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z is (0.3, 0.5, 0.2) and 10 mole% of Pb Ion Ca The same procedure as used in Example 9 is repeated to form a dielectric powder substituted with ions. The dielectric powder thus obtained is dispersed in an organic solvent and kneaded with an organic binder to form a slurry. The slurry thus obtained is formed into a film having a thickness of 40 탆 in accordance with the doctor blade technique used these days. After that, the paste for internal electrodes is printed on the film according to a conventional screen printing method, and then steamed out, laminated, and hot pressed to form a laminate, and then in a desired shape to obtain a green chip for a capacitor. Is cut. The green chip thus obtained is heated to the required temperature so as to remove the binder and fired, and then a silver paste is applied thereto to form an external electrode.

The capacitance of the obtained multilayer ceramic capacitor is measured at room temperature while a DC bias of 0 to 50 V is applied to the multilayer ceramic capacitor by a digital multimeter. The result thus obtained is shown in FIG.

Comparative Example 5

The compounding ratio (x, y, z) of the main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z is (0.3, 0.4, 0.3) and Ca on By Pb The same procedure as used in Example 10 was repeated except that a composition without substitution was used to make a capacitor, and the capacity at the time of applying the DC bias was measured in the same manner as in Example 10. The results thus obtained are shown in FIG. 12 together with the results obtained in Example 10. FIG.

The result shown in FIG. 12 shows lead ions (Pb). ) Ca ions (Ca) It is clearly shown that the capacitor obtained from the magnetic composition of the present invention substituted with) is superior to the capacitor obtained using the composition of Comparative Example 5 when DC bias is applied.

Incidentally, the Curie point of the magnetic composition where the proportion of the main component is outside the range defined by the present invention is shifted to a considerably higher or lower temperature at room temperature, and thus such a composition has a very low dielectric constant at room temperature and is within a practical temperature range. The problem is that the rate of change of permittivity is high. Also, if the amount of lanthanum manganese niobate [La (MnNb) O] to be added to the magnetic composition is outside the range defined by the present invention, the resulting composition is too high in suppression effect, small in capacity, and its bending strength is lowered. Therefore, it cannot be used as a material for manufacturing capacitors. La When the amount of substitution is outside the range defined in the present invention, the obtained composition has a very high inhibitory effect and a small capacity, and the Curie point of the obtained magnetic composition is significantly different from room temperature, so that its dielectric constant at room temperature is significantly low and the firing temperature is high. It cannot be used as a material for producing capacitors because there is a problem that it must be raised to a level (the composition is fired in the temperature range of 1050 to 1100 ° C. and the firing is insufficient, resulting in a decrease in specific resistance). Also Ca When the amount of substitution is outside the range defined in the present invention, the resulting composition has too high an inhibitory effect and a small capacity, and the Curie point of the resulting magnetic composition differs considerably from room temperature so that its dielectric constant at room temperature is considerably low and the firing temperature is increased. It cannot be used as a material for the manufacture of capacitors, since there is a problem that it should be fired (the composition is fired at 1050 ° C., resulting in insufficient firing).

The magnetic composition of the present invention has a small temperature change rate of dielectric constant, and its main component [Pb (MgW) O] x [PbTiO] y [Pb (NiNb) O] z or [Pb (MgNb) O] x [Pb (NiNb) Manganese lanthanum niobate [La (MnNb) O] is added to O] y [PbTiO] z, or Pb as the main component Ions in a predetermined amount Me ca This can be achieved by substituting with ions. In addition, the magnetic composition of the present invention has a small decrease in capacity when DC bias is applied. Accordingly, the magnetic composition may provide a multilayer ceramic capacitor having excellent temperature change rate of dielectric constant and high reliability. The firing temperature is also 1050 to 1100 ° C. or lower, which enables the use of a silver-palladium alloy containing a large amount of silver as the capacitor internal electrode material, and can also reduce the internal electrode manufacturing cost. Likewise, the composition can be applied to a multilayer ceramic capacitor used under a condition of applying a DC bias such as a smoothing capacitor of a power source because the capacity reduction when applying a DC bias is relatively small as described above. The composition may also provide a product having a high bending strength when lanthanum manganese niobate is added, Pb Ion La Me Ca Substitution with ions can provide a product having a high specific resistance.

Claims (10)

_{Three components} consisting of magnesium lead niobate [Pb (Mg _1/3 Nb _2/3 ) O ₃ ], nickel lead niobate [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] and lead titanate [PbTiO ₃ ] The composition was prepared in [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] x [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] y [PbTiO ₃ ] z (where x + y + z = 1.0) When expressed by, in this three-component composition diagram, the following composition points In the main component composition in the line connecting each point of and in the composition range enclosed by said 7 points (a)-(g), lanthanum manganese niobate [La (Mn _2/3 Nb _1/3 ) O ₃ ] as a subsidiary component is 0.01 A magnetic composition, comprising the addition of 10 to 10 mole%. The magnetic composition of claim 1, wherein the amount of lanthanum manganese niobate is 2 to 8 mole%. _{Three components} consisting of lead magnesium tungstate [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate [PbTiO ₃ ] and nickel lead niobate [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] The composition was prepared in [Pb (Mg _1/2 W _1/2 ) O ₃ ] x [PbTiO ₃ ] y [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] z (where x + y + z = 1.0) When expressed by, in this three-component composition diagram, the following composition points In the main component composition in the line connecting each point of and in the composition range enclosed by said 4 points (h) to (k), lanthanum manganese niobate [La (Mn _2/3 Nb _1/3 ) O ₃ ] as 0.01 is 0.01 A magnetic composition, comprising the addition of 10 to 10 mole%. 4. The magnetic composition of claim 3, wherein the amount of lanthanum manganese niobate is 2 to 8 mole%. _{Three components} consisting of magnesium lead niobate [Pb (Mg _1/3 Nb _2/3 ) O ₃ ], nickel lead niobate [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] and lead titanate [PbTiO ₃ ] The composition was prepared in [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] x [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] y [PbTiO ₃ ] z (where x + y + z = 1.0) When expressed by, in this three-component composition diagram, the following composition points It comprises a main component material in the form of a line connecting each point of and in the composition range surrounded by the seven points (a) to (g), wherein 0.01 to 30 meol% of lead ions (Pb ²⁺ ) are lanthanum ions (La ³ +) Magnetic composition, characterized in that by replacing with. The magnetic composition of claim 5, wherein the La ³⁺ substitution amount is 2 to 20 mole%. _{Three components} consisting of lead magnesium tungstate [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate [PbTiO ₃ ] and nickel lead niobate [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] The composition was prepared in [Pb (Mg _1/2 W _1/2 ) O ₃ ] x [PbTiO ₃ ] y [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] z (where x + y + z = 1.0) When expressed by, in this three-component composition diagram, the following composition points It comprises a main component material in the form of a line connecting each point of and in the composition range surrounded by the four points (h) to (k), wherein 0.01 to 30 meol% of lead ions (Pb ²⁺ ) are lanthanum ions (La ³ +) Magnetic composition, characterized in that by replacing with. 8. The magnetic composition of claim 7, wherein the amount of La ³⁺ substitution is 2 to 20 mole%. _{Three components} consisting of lead magnesium tungstate [Pb (Mg _1/2 W _1/2 ) O ₃ ], lead titanate [PbTiO ₃ ] and nickel lead niobate [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] The composition was prepared in [Pb (Mg _1/2 W _1/2 ) O ₃ ] x [PbTiO ₃ ] y [Pb (Ni _1/3 Nb _2/3 ) O ₃ ] z (where x + y + z = 1.0) When expressed by, in this three-component composition diagram, the following composition points Of lanthanum surrounded the lead ions (Pb ²⁺⁾ contained in the main component material, and of which 0.01 to 30meol% in the composition range of the ion on the line, and the four-point (h) to (k) connecting each point (Ca ³ +) Magnetic composition, characterized in that by replacing with. The magnetic composition of claim 9, wherein the Ca ²⁺ substitution amount is 2 to 20 mole%.