CN113443908A

CN113443908A - Ceramic composition, ceramic sintered body and multilayer ceramic electronic component

Info

Publication number: CN113443908A
Application number: CN202010227193.XA
Authority: CN
Inventors: 孙嘉聪
Original assignee: Thinking Electronic Industrial Co Ltd
Current assignee: Thinking Electronic Industrial Co Ltd
Priority date: 2020-03-27
Filing date: 2020-03-27
Publication date: 2021-09-28

Abstract

The present invention provides a ceramic composition, a ceramic sintered body and a laminated ceramic electronic element, wherein the ceramic composition is prepared by adopting a main powder material obtained by firing titanium oxide containing rutile type structure and anatase type structure, so that the laminated ceramic electronic element containing the ceramic sintered body sintered by the ceramic composition can have excellent performances of high resistance temperature coefficient and low room temperature resistance value.

Description

Ceramic composition, ceramic sintered body and multilayer ceramic electronic component

Technical Field

The present invention relates to a ceramic composition, a sintered ceramic body obtained by sintering, and a multilayer ceramic electronic component including the sintered ceramic body, and particularly to a multilayer ceramic electronic component applied to a positive temperature coefficient thermistor.

Background

A Thermistor (Thermistor) is a variable resistor, i.e., a resistor whose resistance value changes with temperature, and is classified into a positive temperature coefficient Thermistor, a negative temperature coefficient Thermistor, and a critical temperature Thermistor. Due to the high accuracy of thermistors in a specific temperature range, there are today a wide range of applications, such as: temperature sensors, inrush current limiters, or self-resetting fuses, etc.

A Positive temperature coefficient thermistor (PTC thermistor) is called a PTC thermistor for short, and its resistance value increases with the temperature rise of the resistor body, and has a Positive temperature coefficient, and after reaching the Curie temperature (Tc) or magnetic transition point, the resistance value rapidly increases, which is also called as a PTC effect. Therefore, the PTC thermistor not only can be used as a heating element, but also has the switching function of overcurrent protection, and can simultaneously realize three functions of heating, sensing and switching, and the PTC thermistor and the heating element are mainly applied.

Since electric appliances used at room temperature such as home appliances and consumer electronics depend on thermistors, for example: as a temperature sensor, a thermistor having a low room temperature resistance will have wide applicability. However, even though the PTC thermistor has the above excellent functions, it still has to be developed to satisfy the market demand due to the limitation of the kind of suitable raw materials, and the thermistor having both a high temperature coefficient of resistance (resistance) and a low room temperature resistance (low room temperature resistance) has yet to be developed.

Disclosure of Invention

The present invention provides a ceramic composition which can be used for a thermistor, thereby increasing the temperature coefficient of resistance of the thermistor and reducing the room temperature resistance value of the thermistor.

To achieve the above object, the present invention provides a ceramic composition comprising: the material comprises a main powder material, a first rare earth material and micro-nano silica glass; wherein the main powder material is formed by firing a main powder mixture containing barium carbonate and titanium oxide, and the titanium oxide contains a rutile structure and an anatase structure; wherein the content of the rutile structure is 20 to 90% by weight, based on the total weight of the titanium oxide.

Preferably, the titanium oxide consists essentially of a rutile structure and an anatase structure. More preferably, the titanium oxide is composed of a rutile structure and an anatase structure.

Preferably, the content of the rutile structure is 20 to 90 wt%, based on the total weight of the titanium oxide, for example: 25 weight percent, 30 weight percent, 35 weight percent, 36 weight percent, 37 weight percent, 38 weight percent, 39 weight percent, 40 weight percent, 45 weight percent, 50 weight percent, 55 weight percent, 56 weight percent, 57 weight percent, 58 weight percent, 59 weight percent, 60 weight percent, 61 weight percent, 62 weight percent, 65 weight percent, 70 weight percent, 75 weight percent, 76 weight percent, 77 weight percent, 78 weight percent, 79 weight percent, 80 weight percent, 81 weight percent, 82 weight percent, 83 weight percent, 84 weight percent, 85 weight percent, 86 weight percent, 87 weight percent, 88 weight percent, 89 weight percent, or 90 weight percent; more preferably, the rutile structure is present in an amount of 55 to 82 weight percent.

According to the present invention, the temperature coefficient of resistance (i.e., α value) of the ceramic composition after sintering can be increased by adjusting the content ratio of the rutile structure to the anatase structure in the titanium oxide.

According to the present invention, the resistance temperature coefficient can be further increased and the resistance value can be reduced by adjusting the content ratio of titanium oxide in the main powder mixture, preferably, based on the total weight of the main powder mixture, wherein the content of titanium oxide is 27.35 wt% to 28.35 wt%, for example: 27.40 weight percent, 27.45 weight percent, 27.49 weight percent, 27.50 weight percent, 27.51 weight percent, 27.52 weight percent, 27.53 weight percent, 27.55 weight percent, 27.58 weight percent, 27.59 weight percent, 27.60 weight percent, 27.61 weight percent, 27.62 weight percent, 27.65 weight percent, 27.67 weight percent, 27.68 weight percent, 27.69 weight percent, 27.70 weight percent, 27.71 weight percent, 27.75 weight percent, 27.78 weight percent, 27.79 weight percent, 27.80 weight percent, 27.81 weight percent, 27.82 weight percent, 27.85 weight percent, 27.90 weight percent, 27.95 weight percent, 27.98 weight percent, 27.99 weight percent, 28.00 weight percent, 28.01 weight percent, 28.02 weight percent, 28.05 weight percent, 28.10 weight percent, 28.15 weight percent, 28.17 weight percent, 28.18 weight percent, 28.19 weight percent, 28.20 weight percent, 28.21 weight percent, 28.22 weight percent, 28.25 weight percent, 28.27 weight percent, 28.28 weight percent, 28.29 weight percent, 28.30 weight percent, or 28.31 weight percent.

Preferably, the content of the barium carbonate is 71.65 wt% to 72.65 wt% based on the total weight of the main powder mixture.

Preferably, the main powder mixture further comprises a first element material, and the first element material is selected from calcium carbonate, strontium carbonate or a combination thereof.

When the main powder mixture comprises calcium carbonate, the calcium carbonate is present in an amount of 0.10 to 0.60 weight percent, based on the total weight of the main powder mixture, for example: 0.11 weight percent, 0.14 weight percent, 0.15 weight percent, 0.16 weight percent, 0.20 weight percent, 0.25 weight percent, 0.30 weight percent, 0.35 weight percent, 0.40 weight percent, 0.45 weight percent, 0.50 weight percent, 0.55 weight percent, or 0.59 weight percent. Preferably, the content of the calcium carbonate is 0.10 to 0.30 weight percent.

When the main powder mixture includes strontium carbonate, the strontium carbonate is contained in an amount of 0.10 to 0.60 weight percent, based on the total weight of the main powder mixture, for example: 0.15 weight percent, 0.20 weight percent, 0.25 weight percent, 0.30 weight percent, 0.35 weight percent, 0.40 weight percent, 0.44 weight percent, 0.45 weight percent, 0.46 weight percent, 0.49 weight percent, 0.50 weight percent, 0.55 weight percent, or 0.59 weight percent. Preferably, the strontium carbonate is contained in an amount of 0.30 to 0.60 wt%.

The main powder mixture is calcined to form a main powder material, and the main powder material contains barium titanate and has a perovskite structure.

In some embodiments, when the main powder mixture comprises barium carbonate, calcium carbonate, strontium carbonate, and titanium oxide, the main powder mixture is calcined to form the main powder material, and the main powder material has a general formula represented by formula a_mBO₃A perovskite structure wherein the a site is selected from barium, strontium, calcium or a combination thereof, the B site is titanium, m is the molar ratio of the a site to the B site, and 1.012 ≦ m ≦ 1.078. Therefore, the lattice constant of the perovskite structure can be further adjusted by adjusting the proportion of the barium, strontium, calcium or titanium element in the main powder material, and accordingly, ceramic sintered bodies with different curie temperatures can be obtained as required.

For example, the above m value may be 1.013, 1.014, 1.015, 1.016, 1.017, 1.018, 1.019, 1.020, 1.021, 1.022, 1.025, 1.028, 1.029, 1.030, 1.031, 1.032, 1.035, 1.038, 1.039, 1.040, 1.041, 1.042, 1.045, 1.048, 1.049, 1.050, 1.051, 1.052, 1.055, 1.058, 1.059, 1.060, 1.061, 1.062, 1.065, 1.068, 1.069, 1.070, 1.071, 1.072, or 1.075.

Preferably, the main powder material has an average particle size of 0.2 to 3 μm and a calcination temperature of 800 to 1200 ℃, for example: 850 deg.C, 900 deg.C, 950 deg.C, 1000 deg.C, 1050 deg.C, 1100 deg.C or 1150 deg.C, preferably 900 deg.C to 1100 deg.C.

Preferably, the calcination time is at least 50 minutes, such as: 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4.0 hours, more preferably 1 hour to 3 hours.

Preferably, based on the total weight of the main powder material, the first rare earth material and the micro-nano silicate glass, the content of the main powder material is 77 weight percent to 96.9 weight percent; more preferably, the content of the main powder material is 79 weight percent to 92.9 weight percent.

According to the present invention, the perovskite structure can be made semiconductive by adding the first rare earth material described above, thereby reducing the electrical resistance value of the obtained ceramic sintered body. Preferably, the first rare earth material includes yttrium (Y), samarium (Sm), niobium (Nb), neodymium (Nd), cerium (Ce), an alloy thereof, or an oxide thereof.

Preferably, the total weight of the main powder material, the first rare earth material and the micro-nano silicate glass is taken as a reference, and the content of the first rare earth material is 0.1 to 3 weight percent; for example, the first rare earth material can be present in an amount of 0.2 weight percent, 0.3 weight percent, 0.4 weight percent, 0.5 weight percent, 0.6 weight percent, 0.7 weight percent, 0.8 weight percent, 0.9 weight percent, 1.0 weight percent, 1.5 weight percent, 2.0 weight percent, or 2.5 weight percent.

In the invention, the temperature required for forming the liquid phase of the micro-nano silicate glass is lower, so that each element can be more uniformly diffused into the crystal lattice of the perovskite structure, and the alpha value of the obtained ceramic sintered body is further improved and the resistance value of the ceramic sintered body is reduced. Preferably, the micro-nano silica glass contains silica, and the content of the micro-nano silica glass is 3 to 20 weight percent based on the total weight of the main powder material, the first rare earth material and the micro-nano silica glass, for example: 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, or 19 weight percent; more preferably, the content of the micro-nano silica glass is 5 to 15 weight percent.

Preferably, the micro-nano silicate glass further comprises a second rare earth material and/or a second element; and the second rare earth material and/or the second element and the silicon dioxide are sintered together to form the micro-nano silicate glass. Preferably, the second rare earth material is any one or a combination of yttrium, samarium, niobium, neodymium and cerium, and the second element comprises any one or a combination of barium, strontium, calcium and titanium.

Preferably, the content of the silicon dioxide is 97.3 to 99.4 weight percent based on the total weight of the micro-nano silicate glass; the content of the second rare earth material is 0.1 to 0.7 weight percent, and/or the content of the second element is 0.5 to 2 weight percent. In some embodiments, the second rare earth material is present in an amount of 0.2 weight percent, 0.3 weight percent, 0.4 weight percent, 0.5 weight percent, or 0.6 weight percent; the second element is present in an amount of 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or 1.9 weight percent.

Preferably, the average particle size of the micro-nano silica glass is 30 nanometers to 3 micrometers.

The invention also provides a ceramic sintered body, which is sintered by the ceramic composition; wherein the ceramic sintered body has a plurality of pores, and a porosity of the ceramic sintered body is 5% to 20%.

According to the present invention, the pores of the ceramic sintered body are spaces formed by the grain boundaries of at least three grains.

According to the present invention, the porosity is obtained by observing and calculating a cross section of the ceramic sintered body randomly selected by a scanning electron microscope. The porosity is represented by the following formula: porosity (%) ═ VH/VT × 100; where VH is the total area of all holes of the cross-section and VT is the total area of the cross-section.

Because the ceramic sintered body is provided with a plurality of holes, an oxygen transmission path can be provided in the oxidation treatment step of the sintering process, so that the porosity is properly increased, the oxygen supplementing efficiency can be increased, and the temperature coefficient of resistance performance of the ceramic sintered body is further improved. Therefore, the porosity can be adjusted by adjusting the content of the silica.

If the ceramic sintered body is too dense, the oxygen transmission path is reduced to impair the oxygen supplementing ability, possibly making the α value perform poorly; on the contrary, if the porosity of the ceramic sintered body is too high, although there are many oxygen supply paths to increase the α value, the problem of insufficient structural strength of the ceramic sintered body is likely to occur, and the failure condition may occur during the subsequent dielectric property test due to insufficient compactness of the ceramic sintered body structure. Therefore, preferably, the porosity of the ceramic sintered body is 5% to 20%. For example: the porosity may be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%.

According to the invention, after the ceramic composition is sintered, the silicon dioxide component in the micro-nano silicate glass is mainly gathered in the holes of the ceramic sintered body to form solid particles, namely the glass phase. The glass phase may also be referred to as a solid glass phase or a glass body, which contributes to further lowering the resistance value and raising the α value of the ceramic sintered body.

Preferably, when the micro-nano silicate glass content in the ceramic composition is more than 3 weight percent, the obtained ceramic sintered body can obviously form a glass phase due to sufficient silicon content.

The present invention also provides a laminated ceramic electronic component, comprising: a ceramic body including a plurality of the above ceramic sintered bodies and a plurality of internal electrodes; wherein the ceramic sintered body and the internal electrode are formed in the ceramic body to overlap each other; and the outer electrodes are respectively arranged on two opposite side surfaces of the ceramic body and are electrically connected with the inner electrodes.

According to the invention, two adjacent inner electrodes are electrically connected to the opposite outer electrodes, respectively.

In the multilayer ceramic electronic component, the plurality of internal electrodes are alternately stacked in parallel in the ceramic body, thereby achieving the effect of reducing the room temperature resistance.

Preferably, the internal electrode includes nickel (Ni).

Preferably, the external electrodes each include any one or a combination of silver (Ag), nickel, and tin (Sn). In some embodiments, the external electrodes are each electrodes of a multilayer structure. For example, the external electrode may be a three-layer external electrode, and the materials of the first to third external electrodes are silver, nickel and tin in sequence.

Preferably, the inner electrodes are each substantially perpendicular (90 degree angle) to the outer electrodes.

Preferably, the stacked ceramic electronic component may further include two protection layers disposed on two opposite surfaces of the ceramic body, wherein the surfaces are parallel to the internal electrodes. The protective layer can avoid the problem of excessive plating when the external electrode is formed by electroplating the laminated ceramic electronic element.

Preferably, the room temperature resistance value of the laminated ceramic electronic component is 1 ohm to 30 ohm, wherein the room temperature is 25 ℃.

According to the present invention, the temperature coefficient of resistance of the stacked ceramic electronic component can be 3.35 ppm/DEG C to 10 ppm/DEG C; preferably, the temperature coefficient of resistance of the above laminated ceramic electronic component is 3.95 ppm/DEG C to 10 ppm/DEG C, for example: 4.0 ppm/deg.C, 4.5 ppm/deg.C, 5.0 ppm/deg.C, 5.5 ppm/deg.C, 6.0 ppm/deg.C, 6.5 ppm/deg.C, 7.0 ppm/deg.C, 7.5 ppm/deg.C, 8.0 ppm/deg.C, 8.5 ppm/deg.C, 9.0 ppm/deg.C, 9.5 ppm/deg.C, or 9.9 ppm/deg.C.

Preferably, the Curie temperature of the laminated ceramic electronic component is 80 to 110 ℃. For example, the Curie temperature of the stacked ceramic electronic component may be 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃, 85 ℃, 86 ℃, 87 ℃, 88 ℃, 89 ℃, 90 ℃, 91 ℃, 92 ℃, 93 ℃, 94 ℃, 95 ℃, 96 ℃, 97 ℃, 98 ℃, 99 ℃, 100 ℃, 101 ℃, 102 ℃, 103 ℃, 104 ℃, 105 ℃, 106 ℃, 107 ℃, 108 ℃, 109 ℃ or 110 ℃, and more preferably, the Curie temperature of the stacked ceramic electronic component is 95 ℃ to 100 ℃.

The present invention further provides an electric appliance comprising the above laminated ceramic electronic component.

Drawings

FIG. 1 is a schematic cross-sectional view of a multilayer ceramic electronic component according to the present invention.

Fig. 2A to 2I are electron micrographs of the cross section of the ceramic sintered body in each of the two experimental sets of multilayer ceramic electronic components, respectively.

Detailed Description

Hereinafter, those skilled in the art can easily understand the advantages and effects of the present invention from the following examples. Therefore, it is to be understood that the description set forth herein is intended merely to illustrate preferred embodiments and not to limit the scope of the invention, which can be modified and varied to practice or apply the teachings of the present invention without departing from the spirit and scope thereof.

Main powder material

First, barium carbonate, strontium carbonate, calcium carbonate and titanium oxide were uniformly mixed in accordance with the compositional ratio (unit is weight percent, wt%) of titanium oxide shown in table 1 to obtain respective main powder mixtures. Wherein, in each main powder mixture, based on the total weight of the main powder mixture, the content of each group of strontium carbonate is 0.45 weight percent, and the content of each group of calcium carbonate is 0.15 weight percent. Next, the main powder mixtures are each calcined at a holding temperature of 900 to 1100 ℃ for 1 to 3 hours, and thus main powder materials 1 to 16 having perovskite-type structures can be fired; and, the main powder materials 1 to 16 are all powders having an average particle diameter of 0.2 to 3 μm. Among the main differences between the main powder materials 1 to 16 are that the main powder mixture used therein contains different contents of the rutile structure and the anatase structure, and that titanium oxide accounts for different total contents of the main powder mixture.

Table 1: formulation of each main powder mixture for firing main powder materials 1 to 16 and m value of main powder materials 1 to 16

The raw materials are all commercial products, wherein the purity of barium carbonate is 99.9 percent, the purity of strontium carbonate is 99.9 percent, and the purity of calcium carbonate is 99.9 percent; and the titanium oxide is titanium dioxide having a rutile structure and/or an anatase structure, and has a purity of 99.5%.

Ceramic composition

The ceramic compositions of the following examples and comparative examples respectively include one of the main powder materials 1 to 16 in table 1, a first rare earth material, and micro-nano silica glass; wherein the total weight of each ceramic composition is fixed, and based on the total weight of the ceramic compositions, the content of the main powder material is 89.5 weight percent, the content of the first rare earth material is 0.5 weight percent, and the content of the micro-nano silicate glass is 10 weight percent. Wherein, the main powder materials 1 to 16 in Table 1 were used in the order of the ceramic compositions of comparative example 1-1, comparative example 1-2, example 1-1 to example 1-5, comparative example 1-3 and example 2-1 to example 2-8.

The first rare earth material is also commercially available, and is niobium oxide with a purity of 99.9%.

The micro-nano silica glass is also a commercial product, has an average particle size of 30 nm to 3 microns, and comprises 98.6 weight percent of silicon dioxide, 0.4 weight percent of rare earth elements and 1 weight percent of at least one of barium, strontium, calcium and titanium.

Ceramic sintered body and multilayer ceramic electronic component comprising same

The methods for producing the ceramic sintered bodies and the multilayer ceramic electronic components of the following examples and comparative examples were as follows: the ceramic composition is prepared by using the ceramic compositions as initial raw materials, using toluene and alcohol as solvents, wherein the addition amount of the solvents can be adjusted according to the required dispersion degree, adding about 0.5 to 0.75 weight percent of macromolecular dispersant (product model number is BYK-110, 111 and/or 115) and about 25 to 30 weight percent of polyvinyl butyral resin binder based on the total weight of the initial raw materials, putting the mixture and zirconium balls into a ball mill, and fully mixing the initial raw materials and the additives by wet grinding to obtain the ceramic slurry. Then, forming the ceramic slurry into a sheet by using a doctor blade method, and drying the sheet at the drying temperature of about 50 to 60 ℃; the drying time is adjusted according to the actual condition to obtain a roll of thin strip.

Dispersing nickel metal powder and organic binder in an organic solvent to prepare an internal electrode paste, and then printing the internal electrode on the thin strip by a screen printing method to form the thin strip with the internal electrode. Taking a thin strip without printing internal electrodes as an upper cover and a lower cover, and clamping a laminated structure formed by a plurality of thin strips with internal electrodes between the upper cover and the lower cover; then, after the step of heat pressure equalizing, the ceramic green body is cut out by using a cutting machine. The ceramic green sheet having a laminated structure was degreased at about 300 ℃ for 24 hours in a protective atmosphere. And calcining the degreased ceramic green body in a reducing atmosphere of nitrogen/hydrogen at 1250 ℃ to 1380 ℃ for about 1 hour to prepare a sintered ceramic body, wherein the sintered ceramic body comprises a plurality of ceramic sintered bodies sintered from the thin strip, the ceramic sintered bodies and a plurality of internal electrodes are overlapped, and the number of the layers of the ceramic sintered bodies and the number of the internal electrodes can be adjusted according to the thickness of the thin strip. And after the sintered ceramic body is subjected to edge rolling and corner grinding, the ceramic body is subjected to oxidation treatment at 700-900 ℃ in the atmospheric environment to form the ceramic body. Respectively coating protective layers on the upper and lower surfaces of the ceramic body to form protective layers parallel to the internal electrodes, and respectively attaching silver on the left and right sides of the ceramic body to form external electrodes to form the laminated ceramic electronic component, wherein the external electrodes are electrically connected with the internal electrodes.

As shown in fig. 1, the stacked semiconductor ceramic electronic component 10 has a ceramic body 100 including a plurality of ceramic sintered bodies 110 and a plurality of internal electrodes 120, the ceramic sintered bodies 110 and the internal electrodes 120 being formed in the ceramic body 100 so as to overlap each other;

external electrodes

200 and 300 respectively disposed on the two

opposite sides

130 and 140 of the ceramic body 100 and electrically connected to the internal electrodes 120, wherein the included angle between the

external electrodes

200 and 300 and the internal electrodes 120 is about 90 degrees; and two passivation layers 400 disposed on the upper and

lower surfaces

150, 160 of the ceramic body, respectively, and approximately parallel to the inner electrodes 120. In addition, two adjacent internal electrodes 120 are separated by the ceramic sintered body 110, and the thickness S between the two adjacent internal electrodes 120 is less than 40 μm.

And (3) characteristic analysis:

in experiment one, α values of the laminated ceramic electronic components of examples 1-1 to 1-5 and comparative examples 1-1 to 1-3 were measured, and the measurement results are shown in Table 2; in experiment two, the room temperature resistance value and the curie temperature were measured in addition to the α values of the laminated ceramic electronic components of examples 1 to 4 and examples 2 to 1 to 2 to 8, which were measured in the same manner as in experiment one, and the microstructure of the ceramic sintered body included in each of the laminated ceramic electronic components was observed and the porosity was calculated, and the measurement results are shown in table 3. Wherein the length of the sample is 0.933 mm (mm), and the cross-sectional area is 2.396 square mm (mm)²) And the measurement is carried out after the laminated ceramic electronic element is stained with silver as an external electrode according to the steps.

First, the room temperature resistance value was measured by applying a voltage to the above-mentioned test sample at room temperature (i.e., 25 ℃) and measuring the current value using a multimeter (brand: HIOKI, model: RM3545) to convert the resistance value.

Then, the alpha value is measured by placing the sample into a thermostatic bath, gradually raising the temperature from 20 ℃ to 250 ℃, and simultaneously converting the resistance value at each temperature according to the method to obtain a resistance value-temperature curve, and obtaining the temperature when the resistance value is twice the resistance value at room temperature, namely 2 times the point. Since the 2-fold point is a phase transition temperature at which the sample to be tested starts to exhibit PTC characteristics and is approximately close to the curie temperature (Tc), the room temperature (25 ℃) and the 2-fold point are T1 and T2, respectively, and the resistance values thereof are R1 and R2, respectively, and the α value is calculated according to the formula of ═ { ln10 × (LogR 2-LogR 1)/(T2-T1) × 100).

And finally, setting the temperature corresponding to the room temperature resistance value of 2 times as the Curie temperature.

Microstructure and porosity calculation were performed by observing the microstructure of the cross section of the ceramic sintered body formed from the ceramic compositions of the two experimental groups with an electron microscope, and calculating the porosity thereof, and the results are shown in table 3.

Table 2: experiment one: results of alpha value test of the laminated ceramic electronic components of comparative example 1-1, comparative example 1-2, example 1-1 to example 1-5, and comparative example 1-3

As can be seen from the contents of Table 2, the ratio of the rutile structure to the anatase structure in the titanium dioxide raw material significantly affects the α value; when the types and the contents of other components are fixed, the alpha value of the finally prepared laminated ceramic electronic element can reach more than 3.35 ppm/DEG C when the rutile structure proportion is 20 to 90 weight percent based on the total weight of the titanium dioxide; even as with examples 1-3, 1-4, the alpha value can reach even above about 4.5 ppm/deg.C for better electrical performance when the ratio of the rutile structure is 55 wt% to 82 wt%.

Table 3: experiment two: test results of the laminated ceramic electronic components of examples 1 to 4 and examples 2 to 1 to 2 to 8

As can be seen from Table 3, the α values of the stacked ceramic electronic components of each group were all 3.35 ppm/deg.C or higher; among them, the α values of the laminated ceramic electronic components of examples 1 to 4 and 2 to 7 were all higher than 4.5 ppm/degree c, and particularly, the α values of the laminated ceramic electronic components of examples 2 to 5 were all higher than 5.0 ppm/degree c, which indicates that the α values and the electrical properties of the laminated ceramic electronic components can be further adjusted by adjusting the total content of titanium dioxide in the main powder mixture. Further, although the α values of examples 2-1 and 2-8 are not as excellent as those of the laminated ceramic electronic components of examples 1-4, 2-2 to 2-7, the α values of examples 2-1 and 2-8 are still within the preferable range in the art, and the thermistor can be prepared.

Next, as is apparent from fig. 2A to 2I, the cross section of the ceramic sintered body formed of the ceramic composition thereof is observed to have pores 170 to provide an oxygen transmission path.

Finally, as can be seen from fig. 2A to 2F and fig. 2H to 2I, the cross section of the ceramic sintered body formed by the ceramic composition of the present invention is clearly observed to have a glass phase 180, which is helpful for improving the oxygen supplement efficiency and electrical performance of the multilayer ceramic electronic component.

It can be confirmed that the main powder material in the ceramic composition of the present invention adopts titanium oxide containing a specific rutile structure ratio as a raw material, so that the ceramic sintered body has an appropriate α value, and the α value can be further increased by adjusting the specific titanium dioxide content ratio, thereby obtaining a multilayer ceramic electronic component with better efficacy.

Claims

1. A ceramic composition comprising:

a main powder material obtained by firing a main powder mixture containing barium carbonate and titanium oxide, and the titanium oxide containing a rutile structure and an anatase structure; wherein the rutile structure is present in an amount of 20 to 90 weight percent, based on the total weight of the titanium oxide;

a first rare earth material; and

micro-nano silica glass.

2. The ceramic composition of claim 1, wherein the content of the titanium oxide is 27.35 to 28.35 wt% based on the total weight of the main powder mixture.

3. The ceramic composition of claim 1, wherein the primary powder mixture further comprises a first elemental material selected from calcium carbonate, strontium carbonate, or a combination thereof; when the main powder mixture comprises calcium carbonate, the calcium carbonate is present in an amount of 0.10 to 0.60 weight percent, based on the total weight of the main powder mixture; when the main powder mixture includes strontium carbonate, the strontium carbonate is contained in an amount of 0.10 to 0.60 wt%.

4. The ceramic composition according to any one of claims 1 to 3, wherein the main powder material is obtained by calcining the main powder mixture at a temperature of 800 ℃ to 1200 ℃ for at least 50 minutes; and the average particle size of the primary powder material is 0.2 to 3 microns.

5. The ceramic composition of claim 1, wherein the first rare earth material comprises yttrium, samarium, niobium, neodymium, cerium, alloys thereof, or oxides thereof.

6. The ceramic composition of claim 1, wherein the primary powder material is 77 wt% to 96.9 wt%, the first rare earth material is 0.1 wt% to 3 wt%, and the micro-nano silicate glass is 3 wt% to 20 wt%, based on the total weight of the primary powder material, the first rare earth material, and the micro-nano silicate glass.

7. The ceramic composition of claim 3, wherein the host powder material has a composition represented by formula A_mBO₃A perovskite structure wherein the a site is selected from barium, strontium, calcium or a combination thereof, the B site is titanium, m is the molar ratio of the a site to the B site, and 1.012 ≦ m ≦ 1.078.

8. A ceramic sintered body sintered from the ceramic composition according to any one of claims 1 to 7; wherein the ceramic sintered body has a plurality of pores, and a porosity of the ceramic sintered body is 5% to 20%.

9. The sintered ceramic body as claimed in claim 8, wherein a glass phase is formed in part of the pores.

10. A laminated ceramic electronic component, comprising:

a ceramic body comprising a plurality of the ceramic sintered bodies according to claim 8 or 9 and a plurality of internal electrodes; wherein the ceramic sintered body and the internal electrode are formed in the ceramic body to overlap each other; and the outer electrodes are respectively arranged on two opposite side surfaces of the ceramic body and are electrically connected with the inner electrodes.

11. The laminated ceramic electronic component as claimed in claim 10, wherein the room temperature resistance value is 1 ohm to 30 ohm, and the temperature coefficient of resistance is 3.95ppm/° c to 10ppm/° c.

12. The laminated ceramic electronic component as claimed in claim 10, wherein the curie temperature is 80 ℃ to 110 ℃.