JP2017206406A - Conductive ceramic composition, conductive member, and ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive ceramic composition having such good conductivity as to have low resistivity having no inferiority in comparison with a metal material and to keep low resistivity even when heat-treated in atmosphere; a conductive member using the conductive ceramic composition; and a ceramic electronic component such as a laminated ceramic capacitor using the conductive member as an electrode.SOLUTION: A conductive ceramic composition contains a main component having a perovskite crystal structure represented by general formula {Sr(VTiZr)O}. In general formula, m is 0.90≤m≤1.10; and x and y satisfy any one of (i) 0.1≤x≤0.6 and y=0, (ii) x=0 and 0.05≤y≤0.15, and (iii) 0.1≤x≤0.6, 0.05≤y≤0.15 and x+y≤0.3. At least internal electrodes 2a to 2f are formed of a conductive member containing the conductive ceramic composition as a main component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a conductive ceramic composition, a conductive member using the conductive ceramic composition, and a ceramic electronic component such as a multilayer ceramic capacitor using the conductive member as an electrode.

  In a ceramic electronic component such as a multilayer ceramic capacitor, a metal internal electrode is embedded in a component body made of a ceramic material, and an external electrode is formed on the surface of the component body.

  However, when the ceramic material diffuses to the electrode side, for example, the internal electrode side, during the heat treatment (firing process) during the manufacturing process, a non-conductive metal oxide layer is formed at the bonding interface between the component element body and the internal electrode. There is a risk of lowering the conductivity.

On the other hand, conductive porcelain materials having a low resistivity comparable to that of metal materials such as Pt such as SrRuO ₃ and SrVO ₃ have been conventionally known. In particular, SrVO ₃ is cheaper than SrRuO ₃ and is expected to be applied to various technical fields.

For example, Non-Patent Document 1 reports the electrical conductivity, thermal expansion, and stability of Y and Al-substituted SrVO ₃ as a promising anode material for a solid oxide fuel cell.

In this non-patent document 1, a perovskite type compound represented by Sr _1-x Y _x V _1-y Al _y O _3-δ (0 ≦ x ≦ 0.4, 0 ≦ y ≦ 0.2) is added at 10 vol%. H _{2 H} 2 -N reducing atmosphere of a mixed gas of ₂ containing 873 ~ was heat-treated at a temperature of 1173K (600 ~ 900 ℃), as a result, 500~1700S / cm comparable electrically conductive metal material It is described that a conductive porcelain material having a resistivity (2 to 0.6 mΩ · cm in resistivity) was obtained.

Patent Document 1 discloses a conductive ceramic material mainly composed of oxide ceramics, and includes at least one oxide particle selected from a group such as RuO ₂ and SrVO ₃ , LiF, Bi ₂ O, and the like. _3. A conductive ceramic material formed from at least one kind of auxiliary particle selected from the group of PbO and the like has been proposed.

In this patent document 1, auxiliary particles such as LiF and Bi ₂ O ₃ are dispersed in a matrix made of conductive oxide particles such as RuO ₂ and SrVO ₃ , so that 1 × 10 ⁻¹ Ω · cm at room temperature. An electrode component suitable for an electrostatic deflector which has a specific electric resistance value (resistivity) of a certain level and suppresses a decrease in the specific electric resistance value even by oxygen plasma treatment is being obtained. Specifically, this Patent Document 1 describes an example in which RuO ₂ is used as a conductive ceramic material and LiF or Bi ₂ O ₃ is used as an auxiliary particle, and 1 × 10 ⁻ after oxygen plasma treatment is described. An electrode component having a specific electric resistance value of ¹ to 1 × 10 ⁻² Ω · cm is obtained.

JP 2002-293629 A (Claim 1, paragraphs [0010], [0019], [0055] to [0057], [0061] to [0063], etc.)

A.A.Yaremcheko et al. “Electrical conductivity, thermal expansion and stability of Y- and Al-substituted SrVO3 as prospective SOFC anode material”, Solid State Ionics, 247-248 (2013), pp86-93

In the SrVO ₃ -based compound, a tetravalent V ion (vanadium ion) is located at the center of the oxygen octahedron of the perovskite crystal structure, and is thereby considered to exhibit conductivity. In Non-Patent Document 1, a SrVO ₃ -based compound in which a part of Sr is substituted with Y and a part of V is substituted with Al is heat-treated in a reducing atmosphere to obtain a low resistivity equivalent to that of a metal material. ing.

However, when heat-treating SrVO ₃ -based compounds in the atmosphere, tetravalent V is easily oxidized to pentavalent V, which causes a significant increase in resistivity and is not suitable as a conductive material to replace metal materials. In particular, it is difficult to use for electrode materials that require good conductivity.

Further, in Patent Document 1, although the auxiliary particles are dispersed in the conductive oxide particles, an attempt is made to ensure oxidation resistance so that the resistivity does not decrease even when oxygen plasma treatment is performed. Since it is insulative, the resistance value is increased, and only a resistivity of about 1 × 10 ⁻¹ Ω · cm can be obtained. Therefore, although it can be used as an electrode material for an electrostatic deflector, it is not suitable for use in an electrode material that requires a good conductivity equivalent to that of a metal material.

  The present invention has been made in view of such circumstances, and has a low resistivity comparable to that of a metal material, and good conductivity that can maintain a low resistivity even when heat treatment is performed in an air atmosphere. It is an object to provide a conductive porcelain composition having a conductive material, a conductive member using the conductive porcelain composition, and a ceramic electronic component such as a multilayer ceramic capacitor using the conductive member as an electrode.

The present inventor conducted intensive research to achieve the above object, and in the SrVO ₃ series compound, by substituting a part of V with Zr or Ti or both Zr and Ti within a predetermined range, Even if it heat-processes in atmosphere, the oxidation of V can be suppressed, Thereby, the electroconductive porcelain composition of the electroconductivity which has a low resistivity comparable to a metal material both before and after heat processing is obtained. The knowledge that it can be obtained was obtained.

The present invention has been made based on such findings, and the conductive ceramic composition according to the present invention is a conductive ceramic composition in which the main component is formed of a SrVO ₃ -based compound having a perovskite crystal structure. The blending molar ratio m of the Sr site to the V site is 0.90 to 1.10, the V site contains at least one of Ti and Zr, and the Ti and the When Ti in Zr is contained, the content of Ti is 0.1 to 0.6 in terms of molar ratio with respect to the total of V and Ti, and the content of Ti and Zr When the Zr is contained, the content of the Zr is 0.05 to 0.15 in terms of molar ratio with respect to the total of the V and the Zr, and both the Ti and the Zr are If contained, the above The Ti content is 0.1 to 0.6 in terms of molar ratio with respect to the total of V, Ti and Zr, and the Zr content is the total of V, Ti and Zr. On the other hand, it is 0.05 to 0.15 in terms of molar ratio, and the total content of Ti and Zr is 0.3 or less in terms of molar ratio with respect to the total amount of V, Ti and Zr. It is characterized by being.

  Further, as a result of further diligent research by the present inventor, a rare earth element such as La, Ce, Pr, Sm, Nd, and Gd that can be substituted for a part of Sr is contained in a predetermined range, or a part of V By including transition elements such as Nb, Ta, W, and Mo that can be substituted in a predetermined range, the temperature change of the resistance value can be further suppressed even when heat treatment is performed in an air atmosphere. It was found that the change rate of the resistance value can be suppressed in the range.

  That is, the conductive ceramic composition of the present invention contains at least one selected from the group of La, Ce, Pr, Sm, Nd, Gd, Nb, Ta, W, and Mo as a subcomponent, The content of the component is preferably 2 mol parts or less with respect to 100 mol parts of the main component.

  The conductive member according to the present invention is characterized in that the main component is formed of the above-described conductive ceramic composition.

  The ceramic electronic component according to the present invention is a ceramic electronic component in which an external electrode is formed on the surface of a component body in which internal electrodes and ceramic layers are alternately laminated, and at least the internal electrode is the conductive member. It is characterized by being formed by.

  According to the conductive porcelain composition of the present invention, since it has the above-mentioned invention-specific matters, the tetravalent Ti or Zr, or both Ti and Zr are replaced with a part of V at the V site. It will be contained. Therefore, even if heat treatment is performed in an air atmosphere, the perovskite structure is maintained and V can be prevented from being oxidized, and it has good resistance to oxidation and has a desired low resistivity. A porcelain composition can be obtained.

  According to the conductive member of the present invention, since the main component is formed of the above-described conductive ceramic composition, it can be applied to various electronic devices having oxidation resistance, low resistivity, and good conductivity. A conductive member can be obtained.

  According to the ceramic electronic component of the present invention, a ceramic electronic component in which an external electrode is formed on a surface of a component body in which internal electrodes and ceramic layers are alternately laminated, wherein at least the internal electrode is the conductive member. Since it is formed, it is possible to obtain various ceramic electronic parts such as a ceramic capacitor having an oxidation resistance and an electrode having good conductivity with a low resistivity that is inferior to that of an electrode made of a metal material. . That is, high-quality various ceramic electronic components having good conductivity can be obtained without forming a non-conductor such as a metal oxide at the interface between the component element body and the electrode even if the firing treatment is performed.

It is sectional drawing which shows typically one Embodiment of the multilayer ceramic capacitor as a ceramic electronic component using the electroconductive ceramic composition of this invention.

  Next, an embodiment of the present invention will be described in detail.

The conductive porcelain composition as one embodiment of the present invention is formed of an SrVO ₃ -based compound having a perovskite crystal structure (hereinafter referred to as “perovskite structure”) as a main component, and Ti is formed at the V site. And at least one of Zr is contained in a form in which a part of V is substituted.

  Specifically, the main component of the present conductive porcelain composition is represented by the following general formula (A).

Sr _m (V _1-xy Ti _x Zr _y ) O ₃ (A)
Here, the mixing molar ratio m of the Sr site to the V site satisfies the formula (1).

0.90 ≦ m ≦ 1.10 (1)
Further, the Ti content molar ratio x and the Zr content molar ratio y in the V site are defined as follows.

(I) When Ti of Ti and Zr is contained in the V site, the molar ratios x and y satisfy the following mathematical formulas (2) and (3).

0.1 ≦ x ≦ 0.6 (2)
y = 0 (3)
(Ii) When Zr of Ti and Zr is contained in the V site, the contained molar ratios x and y satisfy the following formulas (4) and (5).

x = 0 (4)
0.05 ≦ y ≦ 0.15 (5)
(Iii) When both Ti and Zr are contained in the V site, Expressions (6) to (8) are satisfied.

0.1 ≦ x ≦ 0.6 (6)
0.05 ≦ y ≦ 0.15 (7)
x + y ≦ 0.3 (8)
That is, SrVO ₃ has a perovskite type crystal structure in which tetravalent V ions are located in the center of the oxygen octahedron, and has a good conductivity equivalent to that of a metal such as Pt. It can be used as a product.

However, since V ions have a valence of 5 and are stable, when SrVO ₃ is heat-treated in an air atmosphere, tetravalent V ions are oxidized to 5 valences, so that the perovskite structure cannot be maintained. There is a possibility that the resistivity is increased and the conductivity is lowered.

  Therefore, in the present embodiment, as shown in the above mathematical formula (1), the range of the blending molar ratio m is specified, and at least one of Ti and Zr that are stably present in tetravalence is the predetermined range described above. In the V site, a part of V is substituted. As a result, it is considered that V ions are coordinated stably without leaving the perovskite structure, and the oxidation resistance can be improved. Therefore, oxidation can be suppressed even if heat treatment (baking treatment) is performed in an air atmosphere, and as a result, low resistivity can be maintained even if heat treatment is performed, and conductivity having desired good conductivity can be maintained. A porcelain composition can be obtained.

  Next, the reason why the blending molar ratio m and the Ti and Zr content molar ratios x and y are defined in the above-described ranges will be described.

(1) Mixing molar ratio m
The compounding molar ratio m of the Sr site to the V site is 1.00 in the stoichiometric composition, but the compounding molar ratio m is not limited to the stoichiometric composition and can be varied as necessary. Is possible.

  However, if the blending molar ratio m is less than 0.90, a different phase other than the perovskite structure tends to occur in the porcelain composition, which increases the resistivity, which is not preferable.

  On the other hand, if the blending molar ratio m exceeds 1.10, the deviation from the stoichiometric composition becomes large and becomes excessively Sr-site rich, so that the sinterability is lowered and a dense sintered body cannot be obtained. There is a fear.

  Therefore, in the present embodiment, the compounding molar ratio m is defined as 0.90 to 1.10.

(2) When Ti of Ti and Zr is contained Ti, unlike V, which is stable at 5 valences, is stably present at 4 valences. The solid crystal structure stabilizes the crystal structure, so that the perovskite structure can be maintained even if heat treatment (firing treatment) is performed in the atmosphere, the oxidation resistance is improved, and the resistivity is kept low even after heat treatment. It is thought that you can.

  However, in the case where only Ti of Ti and Zr is contained in the V site (y = 0), in order to obtain the above-described effects, the Ti content molar ratio x needs to be 0.1 or more. .

  On the other hand, when the Ti content molar ratio x exceeds 0.6, the Ti content is excessively increased, and although the oxidation resistance can be ensured, the V content molar ratio is relatively small. This is not preferable because the conductivity increases due to an increase in itself.

  Therefore, in the present embodiment, as shown in the mathematical formula (2), when Ti of Ti and Zr is contained, the Ti content molar ratio x is regulated to 0.1 to 0.6. .

(3) In the case of containing Zr of Ti and Zr Since Zr is also tetravalent and stable, like Ti, by substituting a part of V with Zr and dissolving it in the V site It is considered that the crystal structure is stabilized, the perovskite structure can be maintained even when heat treatment (baking treatment) is performed in the air atmosphere, the oxidation resistance is improved, and the resistivity can be kept low even after heat treatment.

  However, when only Zr of Ti and Zr is contained in the V site (x = 0), in order to obtain the above-described effects, the Zr content molar ratio y needs to be 0.05 or more. .

  On the other hand, if the molar ratio y of Zr exceeds 0.15, the content of Zr is excessively increased, and the sinterability may be deteriorated and a dense sintered body may not be obtained.

  Therefore, in the present embodiment, as shown by the above mathematical formula (5), when Zr of Ti and Zr is included, the Zr content molar ratio y is set to 0.05 to 0.15.

(4) In the case of containing both Ti and Zr Since Ti and Zr are both tetravalent and stable, the crystal structure can be stabilized and oxidation resistance can be improved by adding both. The rate can be kept low.

  And also in this case, for the same reason as described in the above (2) and (3), the Ti content molar ratio x is 0.1 to 0.6, as shown in the formulas (6) and (7). The Zr content molar ratio y needs to be 0.05 to 0.15.

  However, even if the mathematical formulas (6) and (7) are satisfied, if the total molar ratio (x + y) exceeds 0.30, the content molar amount of Ti and Zr becomes excessive, and the molar content of V is relative. Less. For this reason, even if the oxidation resistance can be ensured, the resistivity increases and it becomes difficult to obtain a conductive ceramic composition having desired conductivity.

  Therefore, in the present embodiment, when both Ti and Zr are contained, as shown in the mathematical expressions (6) to (8), (a) the molar content ratio x of Ti is 0.1 to 0.6, (B) The Zr content molar ratio y is 0.05 to 0.15, and (c) the total molar ratio (x + y) of the Ti and Zr content molar ratios is 0.30 or less to satisfy the three requirements. Yes.

Thus, this electroconductive porcelain composition is an electroconductive porcelain composition in which the main component is formed of an SrVO ₃ -based compound having a perovskite type crystal structure, and the blending molar ratio m is expressed by the above formula (1). If the V site contains Ti of Ti and Zr, the formulas (2) and (3) are satisfied. If the V site contains Ti and Zr of Zr, the formula When (4) and (5) are satisfied and both Ti and Zr are contained in the V site, since the mathematical expressions (6) to (8) are satisfied, the conductive ceramic composition has a low resistance. In addition, a highly conductive conductive porcelain composition that is inferior to a metal material having a desired low resistivity even when heat treatment (firing treatment) is performed in an air atmosphere because of improving oxidation resistance. Can be obtained.

  Furthermore, the present invention uses the rare earth element Re acting as a donor for divalent Sr and the transition metal element M acting as a donor for tetravalent V for the main component represented by the general formula (A). It is also preferable to add a trace amount as a component. Thus, by adding a small amount of rare earth element Re or transition metal element M as a main component, an increase in resistance value can be more effectively suppressed even when heat treatment is performed, and further, temperature change of resistance value during use can be suppressed. A high-quality conductive ceramic composition that can be suppressed and does not depend on temperature changes can be obtained.

In this case, the conductive porcelain composition can be represented by the general formula (B).
100Sr _m (V _1-xy Ti _x Zr _y ) O ₃ + αRe + βM (B)
Here, the contents of the rare earth element Re and the transition metal element M are not particularly limited as long as the increase in the resistance value and the temperature change of the resistance value due to the heat treatment can be suppressed. The total (α + β) of the metal elements M can be set to 2 mol parts or less with respect to 100 mol parts of the main component.

  The existence form of the rare earth element Re and the transition metal element M is not particularly limited, but preferably acts as a donor for Sr and V, and the rare earth element Re is mainly dissolved in the Sr site, and the transition metal It is preferable that the element M is mainly dissolved in the V site.

  Such rare earth elements Re are not particularly limited, but La, Ce, Pr, Sm, Nd, Gd, etc., which are relatively easily available, can be used.

  The transition metal element M is not particularly limited as long as it acts as a donor for V. For example, Nb, Ta, W, Mo, or the like can be used.

  Next, the manufacturing method of the said electroconductive ceramic composition is explained in full detail.

First, as a ceramic raw material, an Sr compound (for example, SrCO ₃ or the like), a V compound (for example, VO ₂ , a mixture of V ₂ O ₅ and V ₂ O ₃ ), a Ti compound (for example, TiO ₂ or the like), Zr, etc. A compound (for example, ZrO ₂ or the like), a rare earth compound (for example, La ₂ O ₃ or the like), and a transition metal compound (for example, Nb ₂ O ₅ or the like) are prepared as necessary. And the ceramic raw material is weighed according to the desired final form so that the conductive ceramic composition after firing represented by the general formula (A) satisfies the mathematical formulas (1) to (8).

Next, this weighed material is put into a pulverizer such as a ball mill, pulverized and mixed, and then calcined in a reducing atmosphere at a temperature of about 1050 to 1150 ° C., and then pulverized to obtain a conductive material composed of a SrVO ₃ compound. An excellent ceramic raw material powder is obtained. That is, when the above-mentioned weighed product is calcined in an air atmosphere, V may be dissolved and a perovskite structure cannot be formed. For this reason, a calcination treatment is performed in a reducing atmosphere to obtain the above-described conductive ceramic raw material powder.

  Next, this conductive ceramic raw material powder is put into the pulverizer together with an organic binder, a plasticizer and an organic solvent, and mixed in a wet manner to produce a ceramic slurry. Then, the ceramic slurry is formed into a sheet using a forming method such as a doctor blade method to produce a conductive sheet.

  Next, a plurality of the conductive sheets are laminated, and heated and pressed to produce a ceramic laminate. Next, the ceramic laminate is cut to a predetermined size, and then subjected to a binder removal treatment in an air atmosphere at a temperature of about 300 ° C., and then subjected to a firing treatment in an air atmosphere at a temperature of 1300 to 1400 ° C. for about 2 hours. This produces a conductive porcelain composition.

  Thus, this electroconductive porcelain composition replaces a part of V with a predetermined amount of Ti and / or Zr, and contains a predetermined amount of rare earth element Re or transition metal element M as required. A conductive porcelain composition having good oxidation resistance that can withstand firing in the air atmosphere while maintaining a resistivity as low as that of a metal material can be obtained.

  By obtaining a conductive member containing the conductive ceramic composition as a main component, various electronic devices having oxidation resistance, low resistivity, and good conductivity can be realized.

  In this case, the conductive porcelain composition only needs to form the main component (for example, 95 wt ‰ or more) of the conductive member, and if necessary, an additive that does not affect the resistivity and the temperature coefficient of resistance. May be added.

  FIG. 1 is a cross-sectional view dually showing an embodiment of a multilayer ceramic capacitor as a ceramic electronic component using the conductive member.

This multilayer ceramic capacitor is a component in which ceramic layers 1 (1a to 1g) formed of a BaTiO ₃ based compound and internal electrodes 2 (2a to 2f) formed of the above-described conductive member of the present invention are alternately stacked. In addition to the element body 3, external electrodes 4 a and 4 b are formed on both ends of the component element body 3, and first plating films 5 a and 5 b and a second plating are formed on the surfaces of the external electrodes 4 a and 4 b. Films 6a and 6b are respectively formed.

  In this multilayer ceramic capacitor, the internal electrodes 2a, 2c, and 2e are electrically connected to the external electrode 4a, and the internal electrodes 2b, 2d, and 2f are electrically connected to the external electrode 4b. A capacitance is formed between the opposing surfaces of the internal electrodes 2a, 2c, and 2e and the internal electrodes 2b, 2d, and 2f.

  In this multilayer ceramic capacitor, at least the internal electrodes 2a to 2f are formed of the conductive member of the present invention, so that even if firing is performed, the interface between the ceramic layers 1a to 1g and the internal electrodes 2a to 2f is present. No internal conductors such as metal oxides are formed, and the internal electrodes 2a to 2f are excellent in resistance to oxidation and have low conductivity and good conductivity as compared with the case where the internal electrodes 2a to 2f are formed of a metal material. A ceramic capacitor having 2f can be realized.

  This ceramic capacitor can be easily manufactured as follows. First, the electroconductive sheet by which the composition component was adjusted so that general formula (A) may satisfy | fill numerical formula (1)-(8) with the method mentioned above is produced.

Moreover, a dielectric sheet is produced as follows. That is, a ceramic raw material such as BaCO ₃ and TiO ₂ is prepared and weighed in a predetermined amount, and then the weighed material is put into a pulverizer, mixed and pulverized in a wet state, and calcined at a temperature of about 1000 to 1100 ° C. And pulverizing to obtain a dielectric ceramic raw material powder made of a BaTiO ₃ -based compound. Next, the dielectric ceramic raw material powder is wet-mixed together with an organic binder, a plasticizer, and an organic solvent by the pulverizer to prepare a ceramic slurry. Then, the ceramic slurry is formed into a sheet using a forming method such as a doctor blade method to produce a dielectric sheet.

  Next, a predetermined number of the conductive sheets and the dielectric sheets are alternately laminated, and then heated and pressure-bonded, and cut into predetermined dimensions to obtain a ceramic laminate.

  Then, the ceramic laminate is subjected to binder removal treatment at a temperature of about 300 ° C. in an air atmosphere, and the organic binder is burned and removed, followed by firing treatment at a temperature of 1300 to 1400 ° C. for about 2 hours in the air atmosphere. Thus, the component body 3 is produced.

  Next, a conductive paste for external electrodes is applied to both end faces of the component element body 3, and a baking process is performed, thereby forming external electrodes 4a and 4b.

  Here, regarding the conductive material contained in the conductive paste for external electrodes, it is also preferable to use the conductive member as a paste in addition to a base metal material mainly composed of Ni or Cu.

  In addition, it is also preferable to form the external electrodes 4a and 4b by applying a conductive paste for external electrodes to both end faces of the ceramic laminated body and then performing a firing process simultaneously with the ceramic laminated body. It is more effective when a method for forming an external electrode is employed. That is, even when the external electrodes 4a and 4b are simultaneously fired with the ceramic laminate, no metal oxide is formed between the fired component body 3 and the external electrodes 4a and 4b. It becomes possible to produce a multilayer ceramic capacitor having high performance.

  Finally, first plating films 5a and 5b made of Ni, Cu, Ni—Cu alloy, or the like are formed on the surfaces of the external electrodes 4a and 4b by using a plating method, a vacuum deposition method, or the like. Second plating films 6a and 6b made of solder, tin, or the like are formed on the surfaces of the first plating films 5a and 5b, whereby a multilayer ceramic capacitor as shown in FIG. 1 is manufactured.

The present invention is not limited to the above embodiment. For example, this conductor porcelain composition only needs to be a SrVO ₃ based compound as a main component (eg, 97 wt% or more), and a different phase such as Sr ₃ V ₂ O ₈ is mixed in a range that does not affect the characteristics. May be. Also, the ceramic raw material is not limited to carbonates and oxides, and nitrates, hydroxides, organic acid salts, alkoxides, chelate compounds, and the like can be appropriately selected.

Furthermore, in the above embodiment, the baking treatment is performed in an air atmosphere, but this does not prevent the baking process from being performed in a reducing atmosphere such as H ₂ —N ₂ —H ₂ O gas.

Next, examples of the present invention will be specifically described.

[Preparation of sample]
SrCO ₃ , VO ₂ , TiO ₂ , ZrO ₂ , La ₂ O ₃ , and Nb ₂ O ₅ were prepared as ceramic raw materials. And after these ceramic raw materials are weighed so that the component composition shown in Table 1 is obtained after firing, these weighed materials are put into a ball mill and mixed and pulverized wet, and H ₂ having a volume content of 3 vol%. Calcination treatment is performed at 1100 ° C. for 2 hours in a reducing atmosphere composed of a mixed gas of N ₂ —H ₂ containing N, and then pulverized to obtain a general formula {100Sr _m (V _1-xy Ti _x Zr _y ) O ₃ + αLa + βNb} was produced as a conductive ceramic raw material powder.

  Next, this conductive ceramic raw material powder was put into a ball mill together with a polyvinyl butyral organic binder, a plasticizer and ethanol as an organic solvent, and mixed in a wet manner, thereby producing a ceramic slurry. Then, using a doctor blade method, a ceramic slurry was formed into a sheet to produce a rectangular conductive sheet.

Next, this conductive sheet was laminated in multiple layers and heated and pressed to obtain a ceramic laminate. Thereafter, the ceramic laminate is cut to a predetermined size and then heated to 300 ° C. in an air atmosphere to remove the binder to burn and remove the organic binder. Thereafter, the oxygen partial pressure is 10 ⁻¹¹ to 10 ^{−. In} a reducing atmosphere composed of a mixed gas of H ₂ —N ₂ —H ₂ O adjusted to ¹² MPa, a baking treatment was performed at a temperature of 1300 to 1400 ° C. for 2 hours, and samples Nos. 1 to 24 were obtained.

  Each sample of sample numbers 1 to 24 had no warpage, and the outer dimensions were a plate shape having a length of 8 mm, a width of 8 mm, and a thickness of 0.75 mm.

  Next, each sample of sample numbers 1 to 24 was dissolved, and elemental analysis was performed by ICP-AES (inductively coupled plasma-emission spectroscopy) method. As a result, it was confirmed that each sample had the component composition shown in Table 1. It was.

  Further, when each of the samples Nos. 1 to 24 was subjected to a structural analysis using an X-ray diffraction method at a room temperature of 25 ° C., it was confirmed to have a cubic perovskite structure.

  In addition, each of these samples was separately heat-treated at 800 ° C. for 1 hour in an air atmosphere.

[Sample evaluation]
In this example, as described above, for each sample, not only the calcination treatment but also the firing treatment was performed in a reducing atmosphere, and the resistivity of both the sample that was not heat-treated after firing and the sample that was heat-treated was calculated. Measurements were made to evaluate the oxidation resistance of the samples.

That is, for each of the five samples of sample numbers 1 to 24, the resistance value at room temperature 25 ° C. before and after heat treatment was measured using the DC four-terminal van der Pauw method. The resistivity was determined from the dimensions. Furthermore, for each sample before the heat treatment, the resistance value at 100 ° C. is also measured, and the resistance that becomes an index of the temperature change of the resistance value based on the mathematical formula (9) from the measurement result of the resistance value at 25 ° C. and 100 ° C. The temperature coefficient α (10 ⁻³ / ° C.) was determined.

α = 10 ³ (R ₁₀₀ −R ₂₅ ) / R ₂₅ (100−25) (9)
Here, R ₁₀₀ represents a resistance value (mΩ · cm) at 100 ° C., and R ₂₅ represents a resistance value (mΩ · cm) at 25 ° C.

  Table 1 shows the measurement results (average value of five) of the component composition, the resistivity before and after the heat treatment at room temperature, and the resistance temperature coefficient α in each sample of sample numbers 1 to 24. The resistivity was determined as “good” when less than 1 mΩ · cm, and “impossible” when 1 mΩ · cm or more.

  Sample No. 1 contains neither Ti nor Zr in the main component, so that the resistivity is good at 0.042 mΩ · cm at the stage of firing in a reducing atmosphere before the heat treatment, but after the heat treatment it is 100,000 mΩ · cm. It was found that the resistivity was extremely increased at a distance of cm or more, and the oxidation resistance was poor.

  Sample No. 5 contains Ti in the main component, so the resistivity does not change before and after heat treatment and oxidation resistance is ensured, but the Ti content molar ratio x is 0.85 and excessive. Therefore, the resistivity increased to 4.2 mΩ · cm.

  Sample No. 9 contains Zr in the main component, but since its content molar ratio y is excessive at 0.25, the sinterability is inferior, and a dense sintered body cannot be obtained. The resistivity could not be measured.

  Sample No. 13 is the same as Sample No. 5 because Ti and Zr are contained in the main component at a Ti content molar ratio x of 0.25 and a Zr content molar ratio y of 0.15. Although the oxidation resistance can be ensured, the total molar ratio (x + y) of Ti and Zr is 0.40, which exceeds 0.30, and the content of V is relatively small. Increased to 21 mΩ · cm.

  Sample No. 14 is substantially the same as Sample No. 13, and the Ti molar ratio x is 0.45 and the molar molar ratio y of Zr is 0.05, and Ti and Zr are contained in the main V site. Therefore, although the oxidation resistance can be ensured, the total molar ratio (x + y) is 0.50, which exceeds 0.30. Therefore, the resistivity is as large as 6.3 mΩ · cm.

  Sample No. 20 has a compounding molar ratio m of 0.80, becomes excessively V-site rich, and a heterogeneous phase is formed. Therefore, even before heat treatment, the resistivity is as large as 1.5 mΩ · cm, and oxidation resistance is also improved. It was inferior and it turned out that the resistivity after heat processing becomes 100000 mohm * cm or more and increases extremely.

  Sample No. 24 has a compounding molar ratio m of 1.20, becomes excessively Sr-site rich, has poor sinterability, cannot obtain a dense sintered body, and can measure resistivity. There wasn't.

On the other hand, since sample numbers 2 to 4, 6 to 8, 10 to 12, 15 to 19, and 21 to 23 are all within the scope of the present invention, they have good oxidation resistance. In any of the latter, the resistivity is good at less than 1 mΩ · cm, and the resistance temperature coefficient α is 8.1 (10 ⁻³ / ° C.) or less in terms of absolute value, which is 25 ° C., which is a normal use temperature. It was found that the temperature change of the resistance can be sufficiently suppressed between ˜100 ° C.

  In addition, among the samples of the present invention, sample numbers 4, 16 to 19, and 21 to 23 containing La and / or Nb within a predetermined range are sample numbers 2, 3, and 6 that do not contain La and Nb. Compared to ˜8, 10-12, and 15, it was found that the fluctuation range of the resistivity before and after the heat treatment can be suppressed.

  Furthermore, as is clear from the comparison between Sample No. 15 and Sample Nos. 16 to 19, the resistance temperature coefficient α is obtained by adding 0.5 to 2.0 mol parts of La or Nb with respect to 100 mol parts of the main component. It was found that La and Nb have the effect of suppressing the temperature change of the resistance.

  Even a porcelain composition can be used as an electrode material for various ceramic electronic parts such as multilayer ceramic capacitors by realizing a conductive porcelain composition having a low resistivity equivalent to that of metal and good oxidation resistance. To.

1a to 1g Ceramic layers 2a to 2f Internal electrode 3 Component element body 4a, 4b External electrode

Claims (4)

The main component is a conductive porcelain composition formed of a SrVO ₃ -based compound having a perovskite crystal structure,
The molar ratio m of the Sr site to the V site is 0.90 to 1.10.
The V site contains at least one of Ti and Zr,
When the Ti of the Ti and the Zr is contained, the content of the Ti is 0.1 to 0.6 in terms of molar ratio with respect to the total of the V and the Ti,
When the Zr of the Ti and the Zr is contained, the content of the Zr is 0.05 to 0.15 in terms of molar ratio with respect to the total of the V and the Zr,
When both Ti and Zr are contained, the content of Ti is 0.1 to 0.6 in terms of molar ratio with respect to the total of V, Ti and Zr, and the Zr The total content of V, Ti and Zr is 0.05 to 0.15 in terms of molar ratio, and the total content of Ti and Zr is V, Ti and A conductive porcelain composition having a molar ratio of 0.3 or less with respect to the total amount of Zr. Containing at least one selected from the group of La, Ce, Pr, Sm, Nd, Gd, Nb, Ta, W, and Mo as a subcomponent;
The conductive porcelain composition according to claim 1, wherein the content of the subcomponent is 2 mol parts or less with respect to 100 mol parts of the main component.   A conductive member, wherein the main component is formed of the conductive porcelain composition according to claim 1 or 2. A ceramic electronic component in which external electrodes are formed on the surface of a component body in which internal electrodes and ceramic layers are alternately laminated,
A ceramic electronic component, wherein at least the internal electrode is formed of the conductive member according to claim 3.

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