Piezoelectric element

Technical Field

The present invention relates to a piezoelectric element, more specifically, to with the perovskite-type composite oxide as the main component of the piezoelectric ceramic and cubic as the main component of the electrode of the piezoelectric element such as a piezoelectric actuator.

Background Art

By applying a voltage to the piezoelectric ceramic of the piezoelectric actuator of the electrostrictive effect is widely used for precise work positioning and of the device such as the print head of ink jet printer.

Is used as the piezoelectric actuator generally through the piezoelectric element of the piezoelectric ceramic powder in the ceramic green sheet printed conductive paste for forming a conductive layer, which has formed the conducting layer of the ceramic green sheet after the lamination with the specified blocks, at the same time the conductive layer and the ceramic green sheet is sintered, thereby forming a piezoelectric ceramic and the internal electrode co-sintering the piezoelectric ceramic biscuit, and then the two ends of the piezo-electric ceramic Whiteware forming an external electrode is surface.

Furthermore, in this kind of piezoelectric element, as an internal electrode material, has been in use in high-temperature oxidizing atmosphere and is not easy to be oxidized Ag-Pd alloy having a high melting point, such as the noble metal material.

However, if the use of the above-mentioned noble metal material as the internal electrode material, the material cost is high, therefore, in recent years has proposed adopting the low cost and so on is inexpensive cubic metal material as the internal electrode material technical proposal of the use.

For example, Patent document 1 will be disclosed in PZT (Pb (Ti, Zr) O₃: zirconium titanic acid lead) types of piezoelectric ceramic and the cubic, Ag, Ag-Pd and the electrodes are alternately laminated and formed into a laminated piezoelectric element.

Furthermore, Patent document 2 such PZT disclosed in pressed electric ceramic and the internal electrode is formed by sintering as a whole, the above internal electrode to rigid modulus in 160GPa the following cubic or cubic alloy and so on is inexpensive metal material as the main component of the electro-mechanical conversion element.

Furthermore, in Patent document 3 is disclosed in such PZT piezoelectric ceramic and the electrode-forming cubic piezoelectric structural element, also disclosed such PZT of the piezoelectric ceramic is B as is partially in order to have the role of the receptor 2 has a metal cation or the role of the body 5 metal cation replaces the piezoelectric structural element.

Patent literature 1: Japanese Patent opens especially 2002-255644, the

Patent document 2: Japanese Patent opens especially 2002-261343, the

Patent literature 3: particular Japanese Patent 2003-529917, the

Invention disclosure

Furthermore, the above-mentioned is used as the piezoelectric element of the piezoelectric actuator is used as a mechanical drive source, thus demanding large displacement. Therefore, in order to obtain the element size of limited large displacement, the piezoelectric constant d must be large.

On the other hand, the results of the study by the present inventors can be known, the use of cubic and so on is inexpensive metal material as the internal electrode material, even if the sintering in a reducing atmosphere, sintering treatment in the cubic form the internal electrode by oxidation to a certain extent to the piezoelectric ceramic side of the spread, the decline in the piezoelectric characteristic of the piezoelectric constant, and the like.

In other words, have already known to use the cubic and so on is inexpensive metal material as the internal electrode material under the condition of, cubic oxidized in the sintering treatment, it is difficult to obtain with good resistance to oxidation in the past of the use of the situation of Ag-Pd same piezoelectric characteristic.

However, Patent literature 1-3 recorded in the past such PZT piezoelectric ceramic does not have to take account of such a by internal electrode material to be caused by diffusion of the piezoelectric ceramic composition of the characteristic deterioration, so there are difficult to obtain a good having a desired piezoelectric characteristics of the piezoelectric element.

The present invention is completed in view of such problems, aims to provide the same even in the use of inexpensive to cubic base metal other than iron as the main ingredient of the material as the electrode material can be obtained under good piezoelectric characteristics of the piezoelectric element.

The present inventors in order to achieve the above-mentioned purpose and careful studies found, containing receptor element and donor element as the section 3 of the piezoelectric ceramic in such PZT, section through the 3 components in donor compared with the stoichiometric composition of the excessive condition adjustment all constituent than mixes the mole , even if sintered to cubic at the same time as the main component of the electrode, and a piezoelectric ceramic can be obtained also under the condition of having a desired high voltage constant d and high Curie point Tc of the piezoelectric element.

The invention is based on the finding that the completed, the piezoelectric element of the present invention is represented by the following general formula ABO₃ the perovskite-type composite oxide as the main component of the piezoelectric ceramic and cubic as main component and sintered at the same time the electrode of the piezoelectric element, characterized in that the perovskite-type composite oxide, at the same time containing A of Pb, is B containing Ti, Zr, by 2 divalent metal element form a receptor element M^II and by 5 divalent metal element form a donor element M^V, the receptor element M^II and the donor element M^V B is accounted for by the molar ratio of the sum of the set as z, the receptor element M^II and the donor element M^V is the molar ratio of blending of the 1 [...] (2 +b) B and the Ti molar ratio is set when the x, meet the 0.05   z≤ 0.40, 0 <bz/3 the [...] 0.035, the 0 . 345   x≤ 0.480.

Formula ABO₃ in the perovskite-type composite oxide, is in the number of average B stoichiometric composition for 4 price. Therefore, in the PZT piezoelectric ceramic type, in order to have the role of the receptor 2 hexavalent metal element (receptor element M^II) and have as to the role of the body 5 divalent metal element (donor element M^V) replacement B bit elements, Ti or Zr is under the condition of a part of the, receptor element M^II and donor element M^V admixed molar ratio of the stoichiometric composition for the 1 [...] 2.

On the other hand, the use of the cubic as an internal electrode material, even in the reducing atmosphere with the piezoelectric ceramic in the case of sintering at the same time, because the cubic easy to be oxidized and form CuO, diffusion to the piezoelectric ceramic side.

If the CuO diffusion to the piezoelectric ceramic side, because of the number of average B 4 price, the valence number of cubic 2 price, so as a cubic B the acceptor is solid is soluble, play the role of reducing the average valence number.

Therefore, in the present invention, through the use of the average advance B more than 4 a trivalent donor excessive, even if the electrode of the piezoelectric ceramic side of the cubic-soluble is B and fixed, the number of cubic average can compensate the decrease, thereby suppressing a decline in piezoelectric constant d.

Furthermore, of the piezoelectric element of the present invention is characterized in that, the aforesaid receptor element M^II comprises a is selected from Ni, Zn, Mn, Co, Fe, Cr and at least more than one kind of cubic.

Furthermore, of the piezoelectric element of the present invention is characterized in that, the donor element M^V comprises is selected from the group consisting of Nb, Sb, and Ta at least more than one kind of V.

Furthermore, of the piezoelectric element of the present invention is characterized in that, the electrode which forms the internal electrode, is provided with the internal electrode and the piezoelectric ceramic which are alternately stacked laminated structure.

Furthermore, the present inventors earnestly study revealed that, even under the the need for and A B admixed molar ratio is deviated from the stoichiometric composition or as the main ingredient is A a part of the Pb of the metal element with the specified, also can be obtained with the desired high voltage constant d and high Curie point Tc of the piezoelectric element.

In other words, of the piezoelectric element of the present invention is characterized in that, the aforesaid piezoelectric ceramic in order to make up formula Pb_α-a Me_a [(M^II_1/3   M^V_(2+b)/3)_z Ti_x Zr_1-x-z] O₃ (wherein, Me represents a metal element) expressed, α, a respectively meet the 0.965   α≤ 1.020, 0 ≤ a≤ 0.05.

Furthermore, of the piezoelectric element of the present invention is characterized in that, the aforesaid metal element selected from Ba including Me, Sr, Ca, Sc, Y, La, and Nd at least more than one kind of Bi.

Furthermore, the present inventors repeatedly careful studies found that, by making the aforesaid electrode contains Ni, piezoelectric constant d can be further increased, the effect of the all metal in a component of the content of Ni up to 10 weight % of the above from becoming prominent.

In other words, of the piezoelectric element of the present invention is characterized in that, in the aforesaid electrode containing Ni.

Furthermore, of the piezoelectric element of the present invention is characterized in that, the electrode is formed by the metal in a component of a cubic   content is 70 weight %-90 weight % and Ni content is 10 weight %-30 weight % (wherein, cubic and Ni content of the total of 100 weight % the following) is formed by sintering a conductive paste.

Furthermore, the present inventors for having in the metal components containing 10 weight % of the electrode of the Ni more than the piezoelectric element of the cross section of the near the electrode after the inspection, a recognition that the internal electrode is cubic cubic phase and distributes over formed in the piezoelectric ceramic interface and formed in the aforesaid cubic phase of at least any of the empty hole existing in a NiO, that the state of the piezoelectric constant d to.

In other words, of the piezoelectric element of the present invention is characterized in that, the electrode is formed substantially by the cubic cubic phase formed at the same time, the cubic phase and piezoelectric ceramic interface and formed in the aforesaid cubic phase of at least any of the empty hole existing in a NiO.

Furthermore, electrode in the case of containing Ni, the aforesaid receptor element M^II preferably at least comprises Ni.

If the piezoelectric element of the present invention, it is represented by the following general formula ABO₃ the perovskite-type composite oxide as the main component of the piezoelectric ceramic and cubic electrodes at the same time as the main ingredient of the sintered piezoelectric element, at the same time containing A of Pb, is B containing Ti, Zr, by 2 divalent metal element form a receptor element M^II (Ni, Zn, Mn, etc.) and by the 5 divalent metal element form a donor element M^V (Nb, Sb, Ta, and the like), the receptor element M^II and the donor element M^V B is accounted for by the molar ratio of the sum of the set as z, the receptor element M^II and the donor element M^V is the molar ratio of blending of the 1 [...] (2 +b) B and the Ti molar ratio is set when the x, meet the 0.05   z≤ 0.40, 0 <bz/3 the [...] 0.035, the 0 . 345   x≤ 0.480, so B a is compared with the stoichiometry to forming donor excessive, even if the main component of the electrode-forming cubic in the sintering treatment of diffusion to the piezoelectric ceramic side, have also been charge compensation. As a result, can be obtained with the desired high voltage constant d and high Curie point Tc of the piezoelectric element of the piezoelectric characteristic is good.

Specifically, can realize in 2kV/mm with the electric field intensity 550pm/V more piezoelectric constant d₃₃, with 180 the Tc [...] above is suitable for the Curie point of the injection valve of the engine for vehicle, precise mechanical positioning, ink-jet printer printing firstrate of the piezoelectric element of the piezoelectric characteristic is good.

Furthermore, the aforesaid electrode form an inner electrode, is provided with the internal electrode and the piezoelectric ceramic which are alternately stacked laminated structure, therefore, may be obtained efficiently in a limited element having a large size of the displacement of the piezoelectric element.

Furthermore, the aforesaid piezoelectric ceramic in order to make up formula Pb_α-a Me_a [(M^II_1/3 M^V_(2+b)/3)_z Ti_x Zr_1-x-z] O₃ (wherein, Me to Ba, Sr, metallic elements such as Ca) expressed, α, a respectively meet the 0.965   α≤ 1.020, 0 ≤ a≤ 0.05, therefore, even if the and A B molar ratio of blending of α is deviated from the stoichiometric composition or as the main ingredient is A a part of the Pb of the metal element with the specified, also can be obtained with the desired high voltage constant d and high Curie point Tc of the piezoelectric element, suitable for use can be obtained the desired piezoelectric element.

Furthermore, the piezoelectric element of this invention containing Ni in the aforesaid electrode, it is possible to obtain a high piezoelectric constant. This is because it is inferred that the electrode more easily than in the oxidation of cubic Ni, the cubic oxidation during sintering of the piezoelectric ceramic in the proliferation is inhibited the condition.

Furthermore, the aforesaid electrode is formed by the metal in a component of a cubic content is 70 weight %-90 weight % and Ni content is 10 weight %-30 weight % (wherein, cubic and Ni content of the total of 100 weight % the following) is formed by sintering a conductive paste, so that play can be significantly more of the above-mentioned piezoelectric constant d role.

Furthermore, the aforesaid electrode is formed substantially by the cubic cubic phase formed at the same time, the cubic phase and piezoelectric ceramic interface and formed in the aforesaid cubic phase of at least any of the empty hole existing in a NiO, so can get high piezoelectric constant of the piezoelectric element. Because it is inferred that the presence of the NiO, CuO oxidation during the sintering of the piezoelectric ceramic in the proliferation is inhibited the condition.

Furthermore, electrode in the case of containing Ni, the aforesaid receptor element M^II at least comprises Ni, thus in the electrode to the Ni is inhibited proliferation of the piezoelectric ceramic, can effectively inhibit the decline of piezoelectric characteristics. Furthermore, as mentioned above the body preferably B is excessive, on the other hand, self-electrode B Ni solid dissolved in the proliferation of play the role of the receptor and, therefore, can compensate the self-electrode of Ni caused by the proliferation of the number of the drop in average B.

Simple explanation of the Figure

Figure 1 to that of the piezoelectric element of the present invention a cross-sectional view of the embodiment.

Figure 2 to that of the piezoelectric element of the present invention of another embodiment of a cross-sectional view.

Figure 3 to show (embodiment 5) a sample number 72 of the piezoelectric element of the schematized cross-sectional view near the internal electrode layer.

Figure 4 to show (embodiment 5) a sample number 74 the internal electrode layer of the piezoelectric element of the schematized cross-sectional view in the vicinity.

Description of symbols

10: laminated sintered body, 11, 31, 41: piezoelectric ceramic, 12a, 12b, 42, 45: internal electrode, 20a, 20b: external electrode, 32a, 32b: external electrode, 46: cubic phase, 47: NiO phase, 48: air hole.

The best way to implement the invention

The following, the embodiments of the present invention to carry out a detailed description.

Figure 1 to that of the piezoelectric element of the present invention a cross-sectional view of the embodiment.

In this piezoelectric element, to cubic as the main component of the internal electrode 12a, 12b is hidden in laminated sintered body 10 at the same time of, in the laminated sintered body 10 formed with the end surface of the external electrodes 20a, 20b.

Laminated sintered body 10 in particular to the internal electrode 12a, 12b and the piezoelectric ceramic 11 which are alternately stacked laminated structure, the internal electrode 12a in order to can be connected with an external electrode 20b is electrically connected with the end surface of one side of the state of LED out from, the internal electrode 12b and the external electrodes 20a is electrically connected to one side of the state of the LED out from the other end face. Furthermore, these internal electrode 12a, 12b and the piezoelectric ceramic 11 of the manufacturing process in the sintering process is formed by sintering at the same time, thereby forming a laminated sintered body 10.

Piezoelectric ceramic 11 in this embodiment by the action of (I) to form a perovskite-type composite oxide expressed by the.

Pb [(M^II_1/3 M^V_(2+b)/3)_z Ti_x Zr_1-x-z] O₃ … (I)

wherein, M^II is 2 divalent metal element form a receptor element, M^V is 5 divalent metal element form a donor element.

In other words, make up formula (I) is represented by the formula ABO₃ to form a perovskite-type composite oxide expressed, at the same time of solution Pb is A, B bit solution Ti, and Zr 3 ingredient (M^II, M^V).

As the acceptor element M^II, as long as it is for the 4 price of the Ti and Zr has the role of the as 2 can be trivalent metal element, there is no particular limitation, can preferably use Ni, Zn, Co, Mn, Fe, Cr, cubic.

As a donor element M^V, as long as it is for the 4 price of the Ti and Zr has a role of the body 5 can be trivalent metal element, there is no particular limitation, can preferably use Nb, Sb, Ta, volt

Furthermore, composition to z, and b meet x the following formula (1)-(3) blending the condition of.

0.05 the the   z≤ 0.40 [...] (1)

0 <bz/3 the [...] the 0.035 [...] (2)

0.345 the the   x≤ 0.480 [...] (3)

The following, a detailed explanation for the z, bz/3 and x the above formula (1)-(3) the reasons for the limited.

(1) z

Bit B z provisions of section 3 ingredient (M^II, M^V) molar ratio of, if z more than 0.40, due to the decline of Curie point Tc, in piezoelectric dematerialised critical temperature, is not ideal. In other words, section 3 ingredient (M^II, M^V) and Pb having a Curie point Tc of composite oxide than is usually of low characteristic of the PZT, especially if z more than 0.40 containing the excessive 3 ingredient (M^II, M^V), due to the decline of Curie point Tc, is not ideal.

On the other hand, if small z, the Curie point Tc can be increased, but if it is not to 0.05, it would lead to a decline of piezoelectric constant.

Therefore, in this embodiment, the article is B 3 ingredient (M^II, M^V) containing molar ratio to meet the 0.05   z≤ 0.40.

(2) bz/3

Bz/3 of that of the donor element B M^V content, if bz/3 in 0 the following, subsection 3 ingredient (M^II, M^V) admixed molar ratio is stoichiometric or receptor excessive, may lead to a decline of piezoelectric constant d. In other words, if the main component of sintered to the cubic of the electrode, and a piezoelectric ceramic, the sintering treatment of the electrode in the cubic form a part of the formed oxide CuO, diffusion to the piezoelectric ceramic 11 side. B is in the number of average stoichiometric composition for 4 price, the cubic 2 price, so if CuO diffusion to the piezoelectric ceramic 11 side and is dissolved is B perovskite-type composite oxide, plays the role of the receptor. At this time, if bz/3 to 0 or a negative value and section 3 ingredient (M^II, M^V) admixed molar ratio is stoichiometric or receptor excessive, since the electric charge of the bit B 4 decline in price, resulting in the decline of piezoelectric constant d. And, CuO is not spread to the piezoelectric ceramic 11 without the perovskite-type composite oxide is dissolved in the crystal grain boundary segregation CuO, forming lean towards, this also may lead to a decline of piezoelectric constant d.

On the contrary, if bz/3 is of a value of the number of average B with the stoichiometric composition (= 4.000) a donor excessive large, even if the cubic diffusion to the piezoelectric ceramic 11 side, as the receptor element is dissolved is B perovskite-type composite oxide, can also be caused by diffusion of the cubic of reducing the number of average compensation, so can inhibit the decline of piezoelectric constant d.

On the other hand, if bz/3 more than 0.035, the piezoelectric ceramic 11 in the sintering, the temperature rise of the needed by sintering, it is difficult to realize for the cubic the main component of the internal electrode 12a, 12b at the same time of sintering. In other words, in order to simultaneously sintering to obtain the piezoelectric ceramic 11 and cubic as the main component of the internal electrode 12a, 12b, the sintering temperature must be 1000 the left and right [...] the following, if bz/3 more than 0.035 the sintering temperature exceeds 1000 the [...] , it is difficult to simultaneously sintering to obtain the above internal electrode 12a, 12b.

Therefore, in this embodiment, the requirement of the donor element in B M^V/bz of the content of 3 to meet 0 <bz/3 the [...] 0.035.

(3) x

In such piezoelectric ceramics of PZT, solid solution in the composition (quasi-homotype phase boundary) MPB the vicinity of the, high piezoelectric constant d can be obtained. In this embodiment, such as the above-mentioned formula (1) is shown, the section is B 3 ingredient (M^II, M^V) containing molar ratio to meet the 0.05   z≤ 0.40, so if Ti is B in the molar ratio of 0.345 or more than 0.480, MPB is far away from the solid solution, resulting in the decline of piezoelectric constant d.

Therefore, in this embodiment, Ti is B in the molar ratio of x meet the 0.345   x≤ 0.480.

As mentioned above, in this embodiment, the above-mentioned constitution formula (I) of the piezoelectric ceramic 11 in order to meet the formula (1)-(3) blending the condition of, the stoichiometric learning and B compared with a body preferably is excessive, therefore, even if the internal electrode 12a, 12b to cubic under the condition of the main ingredient, it is possible to obtain the piezoelectric ceramic 11 and the internal electrode 12a, 12b can be simultaneously sintering and can inhibit the proliferation of cubic caused in the piezoelectric characteristic of the piezoelectric element.

Furthermore, external electrodes 20a, 20b through the sintering of the piezoelectric ceramic 11 of the two end faces of the sintered coating conductive paste material to the forming process. Furthermore, as forming the external electrodes 20a, 20b of the main component of the electrode material, can use Ag, Ag-Pd alloy, such as cubic, there is no particular limitation.

Furthermore, the above-mentioned constitution formula (I) in, to a Pb A, and A B molar ratio of blending of the stoichiometric composition, but it is also preferably according to the demand and A B admixed molar ratio is deviated from the stoichiometric composition or as the main ingredient is A a part of Pb in the metal element displacement.

Under the circumstances, the piezoelectric ceramic 11 that in order to make up formula (II).

Pb_α-a Me_a [(M^II_1/3 M^V_(2+b)/3)_z Ti_x Zr_1-x-z] O₃ … (II)

Wherein, as the Me, Ca can preferably use, Ba, alkaline earth metal such as Sr, Sc, Y, La, metal or rare earth such as Nd Bi.

Wherein, in order to make up formula (II) form a piezoelectric ceramic 11 under the condition of, and α must satisfy a following formula (4), (5).

0.965 the the   α≤ 1.020 [...] (4)

0 the the   a≤ 0.05 [...] (5)

The following, to be α, a formula (4), (5) a description of the reasons for the limited.

(4) α

Α and A B that of than mixes the mole , if α is not to 0.965, is far away from the stoichiometric composition, sintering drop, in the 1000 [...] sintering temperature of about to make its sintering, it is difficult to simultaneously sintering obtained with cubic as the main component of the internal electrode 12a, 12b.

On the other hand, if more than α 1.020, the molar ratio of admixed position side A excessive, A bit component segregation in the crystalline grain boundary, thus may lead to a decline in the piezoelectric constant.

Therefore, even the B A and the blending of the mol ratios deviate from stoichiometry situations, it must also be the molar ratio to meet the 0.965   α≤ 1.020.

(5) a

A in a specified molar ratio is the replacement, if a more than 0.05, the sintering drop, in 1000 the left and right [...] the sintering temperature of the piezoelectric ceramic sintering, it is difficult to simultaneously sintering to obtain internal electrode 12a, 12b.

Therefore, the need to replace the bit A a meet the molar ratio of the 0   a≤ 0.05.

Furthermore, a replacement the molar ratio of d, the greater the greater the piezoelectric constant, but in the Curie point Tc, therefore, preferably according to the above-mentioned replacement element Me in order to obtain the desired piezoelectric constant and Curie point Tc in the condition of the 0   a≤ 0.05 set appropriately, in the context of a replacement molar ratio.

Furthermore, in the above-mentioned piezoelectric element, to the internal electrode in the cubic as a prerequisite for the main component, preferably comprising Ni the remaining components. Through making the its containing Ni, the piezoelectric constant can be obtained d₃₃ large piezoelectric element.

The mechanism is not clear, but it is inferred that the compared with the cubic through containing in oxidation reduction reaction to balance oxygen partial pressure ratio of oxidation of the Ni, of oxidation of the cubic during sintering is inhibited, CuO to the piezoelectric ceramic 11 diffusion is suppressed.

In other words, at the same time as sintering obtains cubic as the main component of the internal electrode 12a, 12b and the piezoelectric ceramic 11 under the condition of, normally in a piezoelectric ceramic 11 of the constituent elements of a Pb, Zr, Ti, and the like as the oxidation of the electrode material will not be cubic down the oxidation of the sintered oxygen, cubic, however, the Pb of the balance of the oxidation-reduction reaction using of the partial oxygen pressure, is therefore inevitably cubic oxidation to a certain degree.

This case, that of the inner electrode through the conductive paste containing Ni in advance, more easily than cubic Ni is oxidized, oxidation of the oxidation of the cubic is inhibited, the CuO caused by diffusion of the piezoelectric ceramic of the piezoelectric element of the characteristic degradation is suppressed.

Furthermore, so that the internal electrode 12a, 12b in the case of containing Ni, preferably a Ni as the acceptor element M^II. In other words, the internal electrode 12a, 12b and containing Ni in addition to use in other than Ni, Zn or Mn of 2 valence metal element as the receptor element M^II under the condition, if the oxidation of Ni to NiO generated by the piezoelectric ceramic 11 in, it would lead to a characteristic degradation of the piezoelectric element. On the contrary, the internal electrode 12a, 12b in the case of containing Ni, if the piezoelectric ceramic 11 exist in advance as a receptor element Ni M^II, the diffusion to the piezoelectric ceramic 11 side of the restricted amount of Ni exists as a solid solution, so can inhibit the internal electrode NiO 12a, 12b to the piezoelectric ceramic 11 diffusion.

In other words, in the case of the above internal electrode 12a, 12b by the cubic form of the cubic phase is formed at the same time, the cubic phase and piezoelectric ceramic interface and formed in the aforesaid cubic phase of at least any of the empty hole existing in a NiO, can more effectively inhibit oxidation during the sintering to CuO formed by the piezoelectric ceramic 11 side of the diffusion, can realize the piezoelectric ceramic 11 piezoelectric constant d₃₃ further improved.

Furthermore, so that the internal electrode 12a, 12b in the case of containing Ni, as a conductive paste, using modulation is preferably of metal in a component of a cubic content is 70 weight %-90 weight % and Ni content is 10 weight %-30 weight % (wherein, cubic and Ni content of the total of 100 weight % the following) paste.

In other words, if the content of the cubic in more than 90 weight %, Ni of the content of 10 weight %, the Ni content is too small, it is not possible to give full play to the internal electrode contains Ni based on the generated by the effect of increase in the piezoelectric constant. This is because that if too little Ni, unable to give full play to the effect of inhibiting oxidation of the cubic. On the other hand, if the cubic content of 70 weight %, Ni content is more than 30 weight %, the content of Ni is excessive, at the time of sintering is therefore almost all Ni is oxidized, the internal electrode 12a, 12b of the metallic components of is too small, so the internal electrode 12a, 12b in the surface coverage, may be unable to obtain sufficient displacement.

Therefore, the conductive paste in the case of containing Ni, in the metal components is the cubic content of 70 weight %-90 weight % and Ni content is 10 weight %-30 weight %, preferably cubic content is 70 weight %-85 weight % and Ni content is 15 weight %-30 weight % (wherein, cubic and Ni content of the total of 100 weight % of the following).

Furthermore, the invention is not limited to the above-mentioned embodiment. The above-mentioned embodiment, the example as a piezoelectric element having a laminated structure of a laminated piezoelectric element, but as shown in Figure 2, can also be used for the piezoelectric ceramic of the present invention 31 to the two main surfaces forming the electrode 32a, 32b of the piezoelectric element of the veneer.

The following, an embodiment of the present invention specific description.

Embodiment 1

As the ceramic raw material, prepared respectively Pb₃ O₄, TiO₂, ZrO₂, NiO, Nb₂ O₅ powder, in order to reach the table 1 shown in the condition of the composition of the, weighing prescribed amount of these ceramic raw materials are mixed, wet grinding 16 hours later, in an 850 [...] the implementation of the presintered the temperature of the processing 2 hours, by the action of (I) to form a perovskite-type composite oxide expressed by the presintering powder.

Pb [(Ni_1/3 Nb_(2+b)/3)_z Ti_x Zr_1-x-z] O₃ … (I)

Furthermore, the pre-sintered powder and binder are mixed together with pure water, the ceramic slurry is made, through the scraper legal cheng Hou 60um of ceramic green sheets.

Furthermore, preparation of synthetic powder accent Ni powder and cubic cubic: 85 weight %, Ni:15 weight % of the conductive paste, the conductive paste on the ceramic green sheet screen printing implementation, the conductive layer to form a predetermined pattern.

Furthermore, the conductive layer will be formed in the ceramic green sheet after the lamination to a predetermined direction, a conductive layer is formed in the ceramic green sheet holding, then using the pressing machine stitching, forming a laminated body.

Furthermore, the laminate in the 500 [...] the implementation of the temperature of the after-binder treatment, an oxygen concentration 1-2ppm under nitrogen atmosphere of 1000 the sintering treatment temperature of [...] 5 hours, to obtain the ceramic sintered body.

Furthermore, the ceramic sintered body cutting growth 7 mm, width 7 mm, thickness 6 mm size, made laminated sintered body, the conductivity of the powder containing the Ag paste is coated on the two ends of the aforesaid ceramic biscuit after, the 780 the implement under [...] to the temperature of the sintering process, forming an external electrode, then at the temperature 80 the applied in the oil of the [...] 3kV/mm strength of the electric field, to polarization processing, sample number obtained from this 1-35 of the piezoelectric element.

Furthermore, all of the piezoelectric element layer of the internal electrode 80 layer.

Furthermore, the sample number 1-35 frequency of the piezoelectric element is applied 0.1Hz triangular wave, the electric field strength 0-2kV/mm changes within the range of, in an induction probe and the thickness of the differential transformer measuring at this moment should be variable, the measured electric field intensity should be variable which are calculated by dividing the piezoelectric constant d₃₃.

Furthermore, through the impedance analyzer measuring the sample number 1-35 the temperature of the piezoelectric element of the electrostatic capacitance at the time of the change, will display the most large electrostatic capacitance as the temperature of the Curie point Tc.

Table 1 sample number that 1-35 of the component composition, piezoelectric constant d₃₃ and Curie point Tc.

[Table 1]

Said * outside the scope of the present invention

Sample no. 1, 26 and 27 in, z to 0.45, more than 0.40, and therefore recognize the piezoelectric constant d₃₃ high as 695-805pm/V, but the Curie point Tc is the 165-170 [...] , drop to the 170 [...] the following.

Sample number 7, 28 and 29 in, the z 0.03, less than 0.05, and therefore recognize the Curie point Tc is as high as 345-  350 the [...] , but piezoelectric constant d₃₃ to 440-510pm/V, dropped to 510pm/V the following.

Sample number 8, 14 and 20 in, bz/3 to 0.040, more than 0.035, sintering characteristics due to the decline of this, in the above-mentioned sintering condition (under nitrogen atmosphere, sintering temperature of the 1000 [...]) sintering at the same time the internal electrode and the piezoelectric ceramic, cannot obtain the desired sintered body.

Sample number 13, 19 and 25 in, bz/3 to 0, piezoelectric constant d₃₃ dropped to 460-535pm/V. This is because that as the section 3 of the component of (Ni, Nb) to stoichiometric composition is dissolved is B, therefore sintering treatment as an internal electrode material in the cubic and Ni diffusion to the piezoelectric ceramic side.

Sample number 30 in, to x 0.4850, more than 0.480, therefore the piezoelectric constant d₃₃ dropped to 515pm/V. Furthermore, sample number 35 in, for x 0.3400, not to 0.345, therefore the piezoelectric constant d₃₃ dropped to 505pm/V. In other words, the sample number 30, 35 in, away from the MPB solid solution, and therefore recognize the piezoelectric constant d₃₃ drop.

On the contrary, sample number 2-6, 9-12, 15-18, 21-24 and 31-34 in, z, bz/3 and x in the 0.05   z≤ 0.40, 0 <bz/3 the [...] 0.035, the 0 . 345   x≤ 0.480 within the scope of the present invention, therefore, confirm with 550pm/V more piezoelectric constant d₃₃ and 180 the Curie point Tc [...] of the above.

Embodiment 2

Use with (embodiment 1) of the same ceramic raw material, in order to reach the table 2 in the condition shown, weighing prescribed amount of these ceramic raw materials are mixed, wet grinding 16 hours later, in an 850 [...] the implementation of the presintered the temperature of the processing 2 hours, (IIa) by the action of perovskite-type composite oxide expressed by the presintering powder form.

Pb_α [(Ni_1/3 Nb_(2+b)/3)_z Ti_x Zr_1-x-z] O₃ … (II   a)

In other words, as is in a variety of relative to the Pb A B admixed molar ratio of α, to obtain sample number 41-47 the presintering powder.

Furthermore, use and (embodiment 1) of the same method step ·, the sample number is 41-47 of the piezoelectric element, the piezoelectric constant determining d₃₃ and Curie point Tc.

Table 2 indicated that sample number 41-47 of the component composition, piezoelectric constant d₃₃ and Curie point Tc.

[Table 2]

** Expressed in the present invention (claim 3) outside the scope of the

Sample no. 41 in, α is 1.030, more than 1.020, therefore the piezoelectric constant d₃₃ dropped to 410pm/V.

Sample number 47 in, α to 0.960, not to 0.965, sintering characteristics due to the decline of this, in the above-mentioned sintering condition (under nitrogen atmosphere, sintering temperature of the 1000 [...]) sintering at the same time the internal electrode and the piezoelectric ceramic, cannot obtain the desired sintered body.

On the contrary, sample number 42-46 in, α, z, bz/3 and the x the 0.965   α≤ 1.020, the 0 . 05   z≤ 0.40, 0 <bz/3 the [...] 0.035, the 0 . 345   x≤ 0.480 within the scope of the present invention, can be obtained can be obtained and therefore recognize high as 590-790pm/V piezoelectric constant d₃₃ and Curie point Tc also reached as high as about 280 the above [...] has good piezoelectric characteristics of the piezoelectric element.

Embodiment 3

Apart from (embodiment 1) of the same ceramic raw material, is also prepared to BaCO₃, SrCO₃, CaCO₃, Nd₂ O₃, Bi₂ O₃, in order to reach the table 3 composition of in the conditions shown, weighing prescribed amount of these ceramic raw materials are mixed, wet grinding 16 hours later, in an 850 [...] the implementation of the presintered the temperature of the processing 2 hours, (IIb) by the action of perovskite-type composite oxide expressed by the presintering powder form.

Pb_1.000-a Me_a [(Ni_1/3 Nb_2.150/3)_0.2 Ti_0.4225 Zr_0.3775] O₃ … (IIb)

In other words, to obtain α to 1.000, z to 0.2, bz/3 to 0.010, x to 0.4225 and Pb is A in a component of a part of a metal element of the sample number of the replacement Me 51-58 the presintering powder.

Furthermore, use and (embodiment 1) of the same method step ·, the sample number is 51-58 of the piezoelectric element, the piezoelectric constant determining d₃₃ and Curie point Tc.

Table 3 sample number that 51-58 of the component composition, piezoelectric constant d₃₃ and Curie point Tc.

[Table 3]

** Expressed in the present invention (claim 3) outside the scope of the

Sample number 53 in, for a 0.075, more than 0.05, due to the decline of sintering the resulting, in the above-mentioned sintering condition (under nitrogen atmosphere, sintering temperature of the 1000 [...]) sintering at the same time the internal electrode and the piezoelectric ceramic, cannot obtain the desired sintered body.

On the contrary, sample number 51 and 52 in, in a 0.05 the following, but also α to 1.000, z to 0.2, bz/3 to 0.010, x to 0.4225, are within the scope of this invention, therefore, is a confirmation can be piezoelectric constant d₃₃ high as 800-805pm/V and Curie point Tc is higher than the the 240-270 [...] has good piezoelectric characteristics of the piezoelectric element.

Furthermore, the sample number 54-58 can know, even with Sr, Ca, La, replaced or Nd Bi a part of the replacement Ba Pb, also can be obtained with high-pressure electric constant d₃₃ and high Curie point Tc has good piezoelectric characteristics of the piezoelectric element.

Embodiment 4

Apart from (embodiment 1) of the same ceramic raw material, is also prepared to ZnO, MnO, Sb₂ O₅ and Ta₂ O₅, in order to reach the table 4 composition of the in the conditions shown, weighing prescribed amount of these ceramic raw materials are mixed, wet grinding 16 hours later, in an 850 [...] the implementation of the presintered the temperature of the processing 2 hours, (IIc) by the action of perovskite-type composite oxide expressed by the presintering powder form.

Pb_α [(M^II_1/3 M^V_2.150/3)_0.2 Ti_x Zr_0.8-x] O₃ … (IIc)

In other words, to obtain z 0.2, bz/3 to 0.010 and have various receptor element M^II and donor element M^V sample number 61-65 the presintering powder.

Furthermore, use and (embodiment 1) of the same method step ·, the sample number is 61-65 of the piezoelectric element, the piezoelectric constant determining d₃₃ and Curie point Tc.

Table 4 indicated that sample number 61-65 of the component composition, piezoelectric constant d₃₃ and Curie point Tc.

[Table 4]

By the table 4 can know, if the molar ratio of the components of the admixture within the scope of this invention, even as a receptor element M^II in addition to using Ni Zn, Ni-Mn, Ni-Zn, or as a donor element M^V is also used in addition to or other than Nb under the condition of Nb-Ta Sb, also can be obtained with the required high piezoelectric constant d₃₃ and high Curie point Tc of the piezoelectric element of the piezoelectric characteristic is good.

Furthermore, as the acceptor element M^II, view with the Ni, Zn or Mn Co similar nature, Fe, Cr, the cubic 2 hexavalent transition metal is also useful, as the donor element M^V, view with the Nb, Sb, similar Ta V, of the nature of the 5 valence transition metal is also useful. Furthermore, and as the acceptor element M^II does not contain Ni sample number 61 compared with, the sample number containing Ni 62-65 piezoelectric element can obtain more high piezoelectric constant d₃₃.

Embodiment 5

Cubic powder and Ni powder is mixed in a weight ratio of the proportion of the table 5 illustrated blending the conductive paste.

Furthermore, preparation with (embodiment 1) of the sample no. 4 the same components of the ceramic green sheet.

Furthermore, the use of the conductive paste in the ceramic green sheet of silk screen printing, a conductive layer to form a predetermined pattern, is then used (embodiment 1) with the same method for sample number is · 71-76 of the piezoelectric element, the piezoelectric constant determining d₃₃.

Table 5 cubic said conductive paste in a ratio of powder and the Ni powder (than cubic/Ni) and piezoelectric constant d₃₃.

[Table 5]

*** Expressed in the present invention (claim 8) outside the scope of the

Sample number 76 in, of metal component of the conductive paste more easily than in the oxidation of cubic Ni to 50 weight %, more than 30 weight %, and therefore recognize the almost all Ni is oxidized during sintering, therefore, the internal electrode 12a, 12b of the metallic components of is too small, the internal electrode 12a, 12b in the surface coverage.

On the contrary, sample number 71-75 can obtain good piezoelectric constant d₃₃, through make the internal electrode in that the Ni content is increased, the piezoelectric constant d₃₃ further improved. Furthermore, piezoelectric constant d₃₃ to improve the effect of the cubic/Ni than 85/15 prominent above.

Furthermore, the cubic/Ni ratio of 98/2 sample number 72 and cubic/Ni ratio of 85/15 sample number 74 of the piezoelectric element, by SEM (scanning electron microscope) observation of the cross section in the vicinity of the internal electrode, then a WDX (greater wavelength dispersive X-ray) analysis components.

Figure 3 to express sample number 72 near the internal electrode layer patterned cross-sectional view, Figure 4 is indicated that sample number 74 of the schematized cross-sectional view near the internal electrode layer.

As shown in Figure 3, Ni to the low content of 2 weight % sample number 72 in, observe internal electrode 44 in the cubic and an alloy or mixture of Ni 42 is formed around the perimeter of the CuO phase 43. Furthermore, in the Figure 41 said piezoelectric ceramic.

On the other hand, as shown in Figure 4, Ni content increased to 15 weight % of sample number 74 in, internal electrode 45 by the actually observed in a cubic cubic phase 46 and substantially composed of NiO is NiO 47. Furthermore, confirming the majority of the NiO phase 47 distributed in the cubic phase 46 and piezoelectric ceramic 41 interface, formed in a portion of the distribution of cubic phase 46 of the empty hole in 48 the internal. In other words, that the cubic easy to be oxidized than Ni, of oxidation than the cubic form Ni to NiO, CuO first-proliferation than that of the piezoelectric ceramic 41 in, the CuO by the piezoelectric ceramic 41 of the diffusion is suppressed.

Furthermore, NiO phase 47 distributed in most cubic phase 46 and piezoelectric ceramic 41 interface that is because of the following reasons. In other words, since the piezo-electric ceramic 41 containing the composition of the Ni in advance, the piezoelectric ceramic to NiO 41 to inhibit excessive proliferation of, so are not spread to the piezoelectric ceramic 41 is in the cubic NiO distributeld 46 and piezoelectric ceramic 41 interface.

Furthermore, pores 48 that is because the cubic phase 46 and the surface coverage of, this case also confirmed pores 48 as mentioned above is NiO phase 47 filling.