JP2011233863A - Voltage nonlinear resistor porcelain composition and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voltage nonlinear resistor porcelain composition which has small CV product, restrains the growth of a crystal grain and further can reduce a variation of various properties.SOLUTION: The voltage nonlinear resistor porcelain composition contains zinc oxide as a main component, and further contains, by atom%, more than 0.05% but less than 30% an oxide of Co in terms of Co, more than 0.05% but less than 20% an oxide of Sr in terms of Sr, more than 0.01% but less than 20% an oxide of R (R is one selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) in terms of R, more than 0.01% but less than 10% an oxide of Si in terms of Si and more than 0.01% but less than 10% calcium zirconate in terms of CaZrO, with respect to 100 moles zinc oxide, as accessory components.

Description

  The present invention relates to a voltage non-linear resistor ceramic composition suitably used for, for example, a voltage non-linear resistor layer of a multilayer chip varistor, and the voltage non-linear ceramic composition as a voltage non-linear resistor layer. It relates to the electronic components used.

  A varistor as an example of an electronic component having a voltage non-linear resistance layer is used to protect an IC circuit of an electronic device or the like by absorbing or removing an external surge (abnormal voltage) such as static electricity or noise. ing.

  In recent years, the speed of digital signals and the speed of communication have been increasing. In particular, when a varistor is used for a very high-speed signal line such as HDMI, if the varistor has a large capacitance, the transmitted signal is attenuated due to the presence of this capacitance, and the transmitted signal is reduced. There was a problem that accurate transmission was hindered, such as rounding.

  In addition, the drive voltage of the circuit has been lowered, and if the varistor voltage is high, there is a problem that surge and noise cannot be suppressed and the circuit cannot be protected.

  Therefore, in order to realize accurate signal transmission while suppressing surge and noise in the low voltage drive circuit, a varistor having a small capacitance and a low varistor voltage, that is, between the capacitance C and the varistor voltage V, A varistor having a small product (CV product) is desired.

  Patent Document 1 discloses a voltage non-linear resistor containing ZnO as a main component and Pr, Co, Cr, Al, etc., and Si and Ca + Sr as a subcomponent at a specific ratio. However, Patent Document 1 does not describe the capacitance of the voltage non-linear resistor, and it has been unclear whether the CV product can be reduced.

JP 2002-246207 A

  An object of the present invention is to provide a voltage non-linear resistor ceramic composition that has a low CV product, suppresses crystal grain growth, and can reduce variations in various characteristics, and a laminate using the composition It is to provide electronic components such as chip varistors.

In order to achieve the above object, the voltage nonlinear resistor ceramic composition according to the present invention comprises:
Contains zinc oxide as the main component,
As a subcomponent with respect to 100 mol of the zinc oxide,
Co oxide is more than 0.05 atomic% and less than 30 atomic% in terms of Co,
Sr oxide is more than 0.05 atomic% and less than 20 atomic% in terms of Sr,
R oxide (wherein R is at least one selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) , In terms of R, more than 0.01 atomic% and less than 20 atomic%,
Si oxide, more than 0.01 atomic% and less than 10 atomic% in terms of Si,
Calcium zirconate is contained in an amount of more than 0.01 atomic% and less than 10 atomic% in terms of CaZrO ₃ .

  In the present invention, it is possible to suppress the grain growth of crystal grains by making the above specific composition and content, in particular, by including Si oxide and calcium zirconate, while improving various characteristics. In addition, variations in these characteristics can be reduced.

  The electronic component according to the present invention has a voltage non-linear resistor layer composed of the voltage non-linear resistor ceramic composition described above.

  Although it does not specifically limit as an electronic component which concerns on this invention, A laminated chip varistor, a disk varistor, a varistor composite element etc. are illustrated.

FIG. 1 is a cross-sectional view of a multilayer chip varistor according to an embodiment of the present invention. FIG. 2 is a graph showing the relationship between the firing temperature and the average particle diameter of crystal grains for the samples according to the reference example and the comparative example of the present invention. FIG. 3 is a graph showing C.V. of firing temperature and varistor voltage for samples according to Examples, Reference Examples, and Comparative Examples. V. It is a graph which shows the relationship between a value. FIG. 4 is a graph showing the firing temperature and C.V. of the non-linear coefficient for samples according to examples, reference examples, and comparative examples of the present invention. V. It is a graph which shows the relationship between a value. FIG. 5 is a graph showing the firing temperature and the capacitance C.V. for the samples according to Examples, Reference Examples, and Comparative Examples of the present invention. V. It is a graph which shows the relationship between a value. FIG. 6 is a graph showing the C.V. product of the firing temperature and the CV product for the samples according to Examples, Reference Examples and Comparative Examples of the present invention. V. It is a graph which shows the relationship between a value.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

Multilayer Chip Varistor As shown in FIG. 1, a multilayer chip varistor 2 as an example of an electronic component has a configuration in which internal electrode layers 4 and 6, an interlayer voltage nonlinear resistor layer 8 and an outer protective layer 8a are stacked. An element body 10 is included. A pair of external terminal electrodes 12 and 14 are formed at both ends of the element body 10 to be electrically connected to the internal electrode layers 4 and 6 disposed inside the element body 10. The shape of the element body 10 is not particularly limited, but is usually a rectangular parallelepiped shape. Also, there is no particular limitation on the dimensions, and it may be an appropriate dimension according to the application, but usually, length (0.6 to 5.6 mm) × width (0.3 to 5.0 mm) × thickness ( 0.3 to 1.9 mm).

  The internal electrode layers 4 and 6 are laminated so that each end face is exposed on the surface of the two opposite ends of the element body 10. The pair of external terminal electrodes 12 and 14 are formed at both ends of the element body 10 and connected to the exposed end surfaces of the internal electrode layers 4 and 6 to constitute a circuit.

  In the element body 10, outer protective layers 8 a are disposed at both outer ends in the stacking direction of the internal electrode layers 4 and 6 and the interlayer voltage nonlinear resistor layer 8 to protect the inside of the element body 10. ing. The material of the outer protective layer 8a may be the same as or different from the material of the interlayer voltage nonlinear resistor layer 8.

Internal Electrode Layer The conductive material contained in the internal electrode layers 4 and 6 is not particularly limited, but is preferably composed of Pd or an Ag—Pd alloy. The Pd content in the alloy is preferably 95% by weight or more. The thickness of the internal electrode layers 4 and 6 may be appropriately determined according to the use, but is usually about 0.5 to 5 μm.

The conductive material contained in the external terminal electrodes 12 and 14 is not particularly limited, but usually Ag, Ag—Pd alloy, or the like is used. The thickness of the external terminal electrodes 12 and 14 may be appropriately determined according to the use, but is usually about 10 to 50 μm.

Interlayer Voltage Nonlinear Resistor Layer Interlayer voltage nonlinear resistor layer 8 is composed of the voltage nonlinear resistor ceramic composition according to the present embodiment. The voltage nonlinear resistor ceramic composition includes zinc oxide as a main component, Co oxide, Sr oxide, R oxide, Si oxide, and zirconic acid as subcomponents. And calcium.

  Zinc oxide (ZnO) as a main component acts as a substance that exhibits excellent voltage nonlinearity in voltage-current characteristics and a large surge resistance.

  Co oxide acts as an acceptor (electron scavenger) and acts as a substance that maintains voltage nonlinearity. Co oxide content with respect to 100 moles of zinc oxide is more than 0.05 atomic% and less than 30 atomic%, preferably 0.1 to 20 atomic%, more preferably 0.1 to 10 atomic% in terms of Co. is there.

  If the Co oxide content is too small, it tends to be difficult to obtain varistor characteristics, and if it is too large, the varistor voltage tends to increase and the voltage nonlinearity tends to decrease.

  The oxide of Sr acts as an acceptor (electron scavenger) and acts as a substance that maintains voltage nonlinearity. The content of the oxide of Sr with respect to 100 mol of zinc oxide is more than 0.05 atomic% and less than 20 atomic%, preferably 0.1 to 10 atomic%, more preferably 0.1 to 5 atomic% in terms of Sr. is there.

  If the content of the Sr oxide is too small, the CV product (product of the capacitance C and the varistor voltage V) tends to increase, and if it is too large, it easily reacts with the main component zinc oxide. Therefore, it tends to melt depending on the firing temperature.

  The oxide of R acts as a substance that accelerates the diffusion rate of oxygen to the grain boundaries. By adding this, the sintered body can be sufficiently sintered.

  The R element constituting the oxide of R is selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, excluding Sc and Pm. At least one is preferable, and at least Pr is more preferable. The content of the oxide of R with respect to 100 mol of zinc oxide is more than 0.01 atomic% and less than 20 atomic%, preferably 0.05 to 10 atomic%, more preferably 0.1 to 5 atomic% in terms of R. is there.

  By setting the content of the oxide of R in the above range, the composition can be maintained in a semiconducting state and the oxygen diffusion rate into the crystal grain boundary can be increased.

  The Si oxide has an effect of reducing variations in various characteristics (for example, capacitance, varistor voltage, nonlinear coefficient, etc.) without changing the CV product. By reducing the variation in characteristics, the yield of products can be improved. It also has the effect of suppressing the grain growth of crystal grains.

  The content of the oxide of Si with respect to 100 mol of zinc oxide is more than 0.01 atomic% and less than 10 atomic%, preferably 0.05 to 5 atomic%, more preferably 0.05 to 1 atomic% in terms of Si. is there.

  If the Si oxide content is too small, the effect of reducing variation in characteristics tends not to be obtained sufficiently. Moreover, abnormal grain growth of crystal grains occurs, and the crystal grains become non-uniform in size. As a result, good varistor characteristics tend not to be obtained. On the other hand, when the content of Si oxide is too large, the varistor voltage increases and the voltage nonlinearity tends to decrease.

  Note that, when a printing method or a sheet method is employed as a method for manufacturing a laminated chip varistor described later, the content of Si oxide is preferably 5 atomic% or less.

Calcium zirconate (CaZrO ₃ ) has an effect of suppressing grain growth of crystal grains and is larger than the grain growth suppression effect of Si oxide. The content of calcium zirconate with respect to 100 mol of zinc oxide is more than 0.01 atomic% and less than 10 atomic%, preferably 0.05 to 5 atomic%, more preferably 0.05 to 1 atomic% in terms of CaZrO _3. is there.

  If the content of calcium zirconate is too low, abnormal grain growth of crystal grains occurs, and the size of the crystal grains becomes uneven. As a result, good varistor characteristics tend not to be obtained. When the content of calcium zirconate is too large, the varistor voltage tends to increase.

  Since both the oxide of Si and calcium zirconate have an effect of suppressing grain growth of crystal grains, abnormal grain growth does not occur if either one is contained in an appropriate range.

  In the present specification, the varistor voltage refers to a voltage when a current of 1 mA flows. The varistor characteristic (voltage nonlinearity) refers to a phenomenon in which a current flowing through an element increases nonlinearly when a gradually increasing voltage is applied to an electronic component.

  Various conditions such as the thickness and the number of laminated layers of the interlayer voltage nonlinear resistor layer 8 may be appropriately determined according to the purpose and application. In the present embodiment, the thickness of the interlayer voltage nonlinear resistor layer 8 is, for example, about 5 to 100 μm, and the number of stacked layers is, for example, about 10 to 50. Moreover, the thickness of the outer side protective layer 8a is about 100-500 micrometers, for example.

  In the present embodiment, the following characteristics can be realized by setting the composition of the voltage nonlinear resistor ceramic composition to the composition shown above. That is, the product of the capacitance (C) measured at a reference temperature of 25 ° C., a measurement frequency of 1 MHz and an input signal level (measurement voltage) of 1 Vrms, and a varistor voltage (V) measured when the flowing current is 1 mA. A certain CV product is preferably 1700 or less, more preferably 1500 or less, and even more preferably 1300 or less. Further, the non-linear coefficient (α) is preferably 14 or more, more preferably 15 or more, and further preferably 17 or more.

Method for Manufacturing Multilayer Chip Varistor Next, an example of a method for manufacturing the multilayer chip varistor 2 according to this embodiment will be described.

  In this embodiment, the green chip is manufactured by a normal printing method or a sheet method using a paste, fired, and then manufactured by printing or transferring the external terminal electrode and firing. Hereinafter, the manufacturing method will be specifically described.

  First, a voltage nonlinear resistor layer paste, an internal electrode layer paste, and an external terminal electrode paste are prepared. A voltage non-linear resistor material (voltage non-linear resistor ceramic composition powder) is prepared, and this is made into a paint to prepare a voltage non-linear resistor layer paste.

  The voltage nonlinear resistor layer paste may be an organic paint obtained by kneading a voltage nonlinear resistor material and an organic vehicle, or may be an aqueous paint.

  As the voltage non-linear resistor material, the main component and subcomponent oxides, mixtures thereof, and composite oxides can be used. In addition, various compounds that become the above oxides and composite oxides by firing are used. For example, they can be appropriately selected from carbonates, oxalates, nitrates, hydroxides, organometallic compounds, and the like, and can be used in combination.

  What is necessary is just to determine content of each component in a voltage nonlinear resistance raw material so that it may become a composition of the above-mentioned voltage nonlinear resistance ceramic composition after baking. As these raw material powders, those having an average particle diameter of about 0.3 to 2 μm are usually used.

  An organic vehicle is obtained by dissolving a binder in an organic solvent. The binder used for the organic vehicle is not particularly limited, and may be appropriately selected from usual various binders such as ethyl cellulose and polyvinyl butyral. The organic solvent to be used is not particularly limited, and may be appropriately selected from various organic solvents such as terpineol, butyl carbitol, acetone, toluene, and the like according to a method to be used such as a printing method or a sheet method.

  Further, when the voltage nonlinear resistor layer paste is used as a water-based paint, a water-based vehicle in which a water-soluble binder or a dispersant is dissolved in water and a dielectric material may be kneaded. The water-soluble binder is not particularly limited, and for example, polyvinyl alcohol, cellulose, water-soluble acrylic resin, etc. may be used.

  The internal electrode layer paste is prepared by kneading the various conductive materials described above or various oxides, organometallic compounds, resinates, and the like, which become the conductive materials described above after firing, and the above-described organic vehicle. Further, the external terminal electrode paste may be prepared in the same manner as the internal electrode layer paste.

  There is no restriction | limiting in particular in content of the organic vehicle in each above-mentioned paste, For example, what is necessary is just about 1-5 weight% of binders, for example, about 10-50 weight% of binders. Each paste may contain additives selected from various dispersants, plasticizers, dielectrics, insulators, and the like as necessary. The total content of these is preferably 10% by weight or less.

  In the case of using the printing method, the voltage non-linear resistance layer paste is printed a plurality of times on a substrate such as PET with a predetermined thickness to form the green outer protective layer 8a.

  Next, an internal electrode layer paste is printed in a predetermined pattern on the outer protective layer 8a to form a green internal electrode layer 4. Next, a voltage non-linear resistance layer paste is printed a plurality of times at a predetermined thickness on the internal electrode layer 4 in the same manner as described above to form a green interlayer voltage non-linear resistance layer 8. .

  Next, the internal electrode layer paste is printed in a predetermined pattern on the interlayer voltage nonlinear resistor layer 8 to form the green internal electrode layer 6. The internal electrode layers 4 and 6 are printed so as to be exposed to different end surfaces.

  Finally, a voltage non-linear resistance layer paste is printed a plurality of times with a predetermined thickness on the internal electrode layer 6 in the same manner as described above to form a green outer protective layer 8a. Then, pressurizing and pressure bonding with heating, cutting into a predetermined shape, and then peeling off from the substrate to obtain a green chip.

  When the sheet method is used, a green sheet is formed using the voltage non-linear resistor layer paste, and then a predetermined number of the green sheets are laminated to form the outer protective layer 8a shown in FIG. To do.

  Next, an internal electrode layer paste is printed in a predetermined pattern on the outer protective layer 8a to form a green internal electrode layer 4. Similarly, a green internal electrode layer 6 is formed on another outer protective layer 8a.

  These are sandwiched between interlayer voltage nonlinear resistance layers 8 formed by laminating a predetermined number of green sheets, and the internal electrode layers 4 and 6 face each other so as to be exposed on different end surfaces. Overlap, pressurize and pressurize while heating, cut into a predetermined shape to make a green chip.

  Next, the green chip is subjected to binder removal processing and firing to produce a sintered body (element body 10).

  The binder removal processing of the green chip may be performed under normal conditions. For example, in an air atmosphere, the temperature rising rate is about 5 to 300 ° C./hour, the holding temperature is about 180 to 400 ° C., and the temperature holding time is about 0.5 to 24 hours.

  The green chip may be fired under normal conditions. For example, in an air atmosphere, the heating rate is about 50 to 500 ° C./hour, the holding temperature is about 1000 to 1400 ° C., the temperature holding time is about 0.5 to 8 hours, and the cooling rate is about 50 to 500 ° C./hour. To do. If the holding temperature is too low, densification is insufficient, and if the holding temperature is too high, there is a tendency that the electrodes are interrupted due to abnormal sintering of the internal electrodes.

  The sintered body (element body 10) obtained as described above is subjected to end face polishing, for example, by barrel polishing or sand blasting, and the external terminal electrode paste is applied and fired to form the external terminal electrodes 12 and 14. . The firing conditions of the external terminal electrode paste are preferably, for example, about 600 minutes to 900 ° C. for 10 minutes to 1 hour in an air atmosphere.

  The multilayer chip varistor 2 of the present embodiment manufactured in this way is connected to, for example, a high-speed transmission circuit or the like, and absorbs or removes external surges (abnormal voltages) such as static electricity or noise, and the like. Used for protection.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, In the range which does not deviate from the summary of this invention, it can implement with a various aspect.

  For example, in the above-described embodiment, the multilayer chip varistor is exemplified as the electronic component according to the present invention. However, the electronic component according to the present invention is not limited to the multilayer chip varistor, and is a voltage nonlinear resistor ceramic having the above composition. Any material may be used as long as it has a voltage non-linear resistance layer composed of a composition.

  Further, as shown in FIG. 1, the internal electrode layer is not limited to a single layered chip varistor. In FIG. 1, only one pair of internal electrode layers is provided, but a plurality of pairs of internal electrodes may be stacked, or a multilayer chip varistor in which a large number of internal electrodes are stacked may be used.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
First, a main component material (ZnO) and subcomponent materials were prepared. Oxides, carbonates, carbonate hydrates, and the like were used as the raw materials for the accessory components.

  Next, these raw materials are blended so that the composition after firing becomes the amount shown in Table 1 with respect to 100 mol of zinc oxide as a main component, and an organic binder, an organic solvent and a plasticizer are added, and a ball mill is added. For about 20 hours to prepare a slurry.

  Using this doctor blade method, a green sheet having a thickness of 30 μm is produced on a PET film by using a palladium paste on a coated green sheet, and is printed in a desired shape by screen printing. It dried and formed the internal electrode 4 shown in FIG. Next, the internal electrode 6 shown in FIG. 1 was formed in the same manner.

  Furthermore, the outer protective layer 8a as the outermost layer was formed by stacking a plurality of green sheets having the same composition.

  Thereafter, these were heated and pressure-bonded, and then cut into a predetermined chip shape to obtain a green chip.

  The green chip was subjected to binder removal treatment at 350 ° C. for 2 hours and then fired in air at 1175 ° C. for 2 hours to obtain a sintered body to be a multilayer chip varistor element body.

Next, an electrode paste mainly composed of Ag was applied to both ends of the obtained sintered body and baked at 800 ° C. to form terminal electrodes 12 and 14. In this way, a multilayer chip varistor having the cross-sectional configuration shown in FIG. 1 was obtained. The size of the obtained varistor sample was 3.2 mm × 1.6 mm × 0.6 mm, the thickness of the voltage nonlinear resistor layer was 65 μm, and the number of voltage nonlinear resistor layers sandwiched between the internal electrode layers. Was set to 1. The overlapping area of the internal electrode layers was 1.3 mm ² .

  Using the obtained varistor sample, the varistor voltage, nonlinear coefficient and capacitance were measured.

By connecting the varistor voltage varistor sample to a DC constant voltage power source, measuring the voltage acting between both electrodes of the varistor sample with a voltmeter, and reading the current flowing through the varistor sample with an ammeter, the varistor voltage (V _{1 mA)} ) Specifically, when the current flowing through the varistor sample was 1 mA, the voltage acting between the electrodes of the varistor sample was read with a voltmeter, and the value was taken as the varistor voltage. The unit was V. In this example, 100 V or less was considered good. The results are shown in Table 1.

Non-linear coefficient (α)
The non-linear coefficient indicates the relationship between the voltage and current applied between the electrodes of the varistor sample when the current flowing through the varistor sample changes from 0.1 mA to 1 mA, and was obtained from the following equation. In this example, 14 or more was considered good. The results are shown in Table 1.

α = log (I ₁ / I _0.1 ) / log (V ₁ / V _0.1 ) = 1 / log (V ₁ / V _0.1 )

V ₁ means a varistor voltage when a current of I ₁ = 1 mA is passed through the varistor sample, and V _0.1 is when a current of I _0.1 = 0.1 mA is passed through the varistor sample. Means varistor voltage. The larger the nonlinear coefficient α, the better the varistor characteristics.

Capacitance capacitance (C), compared varistor sample at the reference temperature 25 ° C. by a digital LCR meter (YHP Co. 4274A), was measured under the conditions of frequency 1 MHz, the input signal level (measured voltage) 1 Vrms (Unit is pF). In this example, 100 or less was considered good. The results are shown in Table 1.

CV product The CV product was calculated by calculating the product of the varistor voltage (V) and the capacitance (C) obtained above. The smaller the CV product, the better. The results are shown in Table 1.

  From Table 1, when the content of subcomponents is outside the range of the present invention (Sample Nos. 1, 8 to 10, 15, 16, 21, 27, and 33), the varistor voltage, nonlinear coefficient, capacitance It was confirmed that at least one of the CV product and the CV product tended to be inferior.

  In Sample No. 15, since the content of the Sr oxide was too large, the Sr oxide reacted with the zinc oxide, which is the main component, to melt, and the characteristics could not be evaluated. In Sample Nos. 22 and 28, either Si oxide or calcium zirconate had an appropriate content, so abnormal grain growth did not occur and good characteristics were obtained. However, Sample No. 22 was not able to reduce the variation in characteristics, and Sample No. 28 was not sufficiently effective in suppressing grain growth. For sample No. 26, the voltage non-linear resistor layer was formed by sheet molding, and thus characteristics were not obtained. For example, any varistor having a voltage non-linear resistor layer formed by compression molding or the like is desirable. The following characteristics can be obtained.

  On the other hand, when the content of the subcomponent is within the scope of the present invention (sample numbers 2 to 7, 11 to 14, 17 to 20, 23 to 25, and 29 to 32), the varistor voltage and the nonlinear coefficient It was confirmed that the electrostatic capacity and the CV product were all good.

Example 2
With respect to 100 mol of ZnO, the Co oxide contains 1.2 atomic% in terms of Co, the Sr oxide contains 0.5 atomic% in terms of Sr, and the Pr oxide contains 0.5 atomic% in terms of Pr. A laminated chip varistor sample (sample number 51) was produced in the same manner as in Example 1 except that the firing temperature was 1125 ° C, 1150 ° C, and 1175 ° C. Further, with respect to 100 mol of ZnO, Co oxide is 1.2 atomic% in terms of Co, Sr oxide is 0.5 atomic% in terms of Sr, Pr oxide is 0.5 atomic% in terms of Pr, zircon. A laminated chip varistor sample (sample number 52) was prepared in the same manner as in Example 1 except that calcium oxide was contained in an amount of 0.06 atomic% in terms of CaZrO ₃ and the firing temperature was 1125 ° C, 1150 ° C, 1175 ° C, 1200 ° C. ) Was produced.

  That is, the difference between sample number 51 (comparative example) and sample number 52 (reference example) is whether or not calcium zirconate is contained. For sample number 51 and sample number 52, the average particle size was measured by the method described below.

  The average particle size was measured by cutting the varistor sample so that the cross section of the voltage nonlinear resistor layer appeared, observing the cross section with a scanning electron microscope (SEM), and taking an SEM photograph. The SEM photograph was subjected to image processing by software, the boundaries of the dielectric particles were determined, and the area of each dielectric particle was calculated. Then, the particle diameter was calculated by converting the calculated area of the dielectric particles into an equivalent circle diameter. The average value of the obtained particle diameters was defined as the average particle diameter. The particle diameter was calculated for 20 dielectric particles. The results are shown in FIG.

Furthermore, with respect to 100 mol of ZnO, Co oxide is 1.2 atomic% in terms of Co, Sr oxide is 0.5 atomic% in terms of Sr, Pr oxide is 0.5 atomic% in terms of Pr, Si The same as Example 1, except that 0.028 atomic% in terms of Si and calcium zirconate in an amount of 0.06 atomic% in terms of CaZrO ₃ were included, and the firing temperatures were 1125 ° C., 1150 ° C., and 1175 ° C. Thus, a multilayer chip varistor sample (Sample No. 53: Example) was produced.

  And about sample number 51, sample number 52, and sample number 53, a varistor voltage, a nonlinear coefficient, and an electrostatic capacitance are measured with respect to 10 samples, respectively, and the variation in the measured value is C.I. V. Evaluation was made as a value (coefficient of variation). The measurement conditions were the same as in Example 1. In addition, the CV product variation from the measured values of varistor voltage and capacitance is also C.I. V. Evaluated as a value.

C. for varistor voltage V. The values are shown in FIG. V. Values are shown in FIG. V. The values are shown in FIG. V. The values are shown in FIG. Note that C.I. V. The value is represented by the following equation: C.I. V. The greater the value, the greater the variation.
C. V. Value = (standard deviation / average value) × 100

  From FIG. 2, it was confirmed that the grain growth of crystal grains can be suppressed by containing calcium zirconate. Moreover, it has confirmed that the effect which suppresses a grain growth was so large that a calcination temperature became high.

  From FIGS. 3-6, it has confirmed that the variation in a characteristic cannot fully be reduced only by containing calcium zirconate. However, it was confirmed that variation in characteristics can be reduced by further containing an oxide of Si.

2 ... Multilayer chip varistor 4, 6 ... Internal electrode layer 8 ... Interlayer voltage non-linear resistance layer 8a ... Outer protective layer 10 ... Element body 12, 14 ... External terminal electrode

Claims (2)

Contains zinc oxide as the main component,
As a subcomponent with respect to 100 mol of the zinc oxide,
Co oxide is more than 0.05 atomic% and less than 30 atomic% in terms of Co,
Sr oxide is more than 0.05 atomic% and less than 20 atomic% in terms of Sr,
R oxide (wherein R is at least one selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) , In terms of R, more than 0.01 atomic% and less than 20 atomic%,
Si oxide, more than 0.01 atomic% and less than 10 atomic% in terms of Si,
A voltage nonlinear resistor ceramic composition comprising calcium zirconate in an amount of more than 0.01 atomic percent and less than 10 atomic percent in terms of CaZrO ₃ .   The electronic component which has a voltage non-linear resistance layer comprised from the voltage non-linear resistance ceramic composition of Claim 1.

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