A piezoelectric ceramic composite material and a preparation method thereof

Abstract

The present invention provides a piezoelectric ceramic composite material and a preparation method thereof, the chemical composition of which is: (1-x)Pb(Ni 1 / 3 Nb 2 / 3 )O3‑x Pb(ZrTi)O3‑y MnO2‑MeO z ‑Li2CO3‑Bi2O3‑Pb m O n , where x is 0.4-0.99, which represents the Pb(ZrTi)O3 in Pb(Ni 1 / 3Nb 2 / 3 )O3-Pb(ZrTi)O3 system; the molar ratio of Zr / Ti is 30 / 70-60 / 40; y is 0.01wt%-1wt%, which represents the molar ratio of MnO2 in (1-x)Pb(Ni 1 / 3 Nb 2 / 3 )O3-x Pb(ZrTi)O3-y MnO2 system weight percentage; the present invention utilizes MO2, Pb m O n The synergistic effect of the PNN-PZT piezoelectric ceramic composite material and the additional sintering agent achieves low-temperature sintering, reducing the sintering temperature of the PNN-PZT piezoelectric ceramic composite material to below 950°C. The piezoelectric ceramic composite material of the present invention has a higher dielectric constant and piezoelectric coefficient than traditional PZT ceramics within a wide range of PNN components, while taking into account a higher mechanical quality factor Qm, lower dielectric loss and high dielectric constant.

Description

Technical Field

[0001] The present invention relates to the technical field of piezoelectric ceramics, and in particular to a piezoelectric ceramic composite material and a preparation method thereof. Background Art

[0002] Piezoelectric materials are renowned for their ability to convert electrical energy into mechanical energy, providing the foundation for a wide range of transducers, sensors, buzzers, inkjet printers, oceanographic radar, ultrasound equipment, and medical imaging devices. Currently, the most common piezoelectric ceramic used in applications is PZT (particularly hard PZT), which has a low dielectric constant (500-1500), resulting in insufficient imaging sensitivity and bandwidth. Furthermore, the fabrication of multilayer devices such as piezoelectric transducers, transformers, and generators requires miniaturization, high capacitance, high step-up or step-down ratios, and low sintering temperatures (<960°C) to accommodate inexpensive silver pastes and achieve appropriate densification and shrinkage. Substrate compatibility also requires low sintering temperatures, providing a broad design space for sensor and electronic integration. Therefore, the development of high-dielectric-constant piezoelectric ceramics and their low-temperature sintering methods are desirable and promising for more versatile device fabrication and applications.

[0003] An important way to improve the dielectric constant of PZT ceramics is to design relaxor-PZT solid solution to utilize the relaxor ceramic Pb(B' x B” 1-x )O3 introduced MPB characteristics and high dielectric constant characteristics. Relaxor ceramics include Pb(Ni 1 / 3 Nb 2 / 3 )O3(PNN)、Pb(Mg 1 / 3 Nb 2 / 3 )O3(PMN)、Pb(Zn 1 / 3 Nb 2 / 3 )O3(PZN)、Pb(Sc 1 / 2 Ta 1 / 2 )O3、Pb(Sc 1 / 2 Nb 1 / 2 )O3、Pb(In 1 / 2Nb 1 / 2 )O3、Pb(Fe 1 / 2 Nb 1 / 2 )O3、Pb(Fe 2 / 3 W 1 / 3 )O3、Pb(Sb 1 / 2 Nb 1 / 2 )x (Ni 1 / 3 Nb 2 / 3)y(Zr,Ti)zO3. The dielectric constant can be modulated to a greater extent between 1000 and 10000, and even the hard piezoelectric solid solution formed by trivalent cation doping can reach 1000-3000, which will further improve the piezoelectric coefficient. However, these lead-containing solid solutions have not yet reached high density at sintering temperatures below 1000°C, and the high volatility of lead oxide during the sintering process leads to uneven composition. The importance of high density lies in the fact that the piezoelectricity after sintering comes from the intrinsic polarization contribution inside the grains, rather than the interface polarization mechanism. Existing solutions are still limited to sintering temperatures of 1000-1100°C by adding only certain glass or oxide additives.

[0004] To lower the sintering temperature of traditional PZT ceramics, researchers have developed various glass frits. For example, Li et al. used B2O3-Bi2O3-CdO glass frit, Dai et al. used B2O3-Bi2O3-MeO-CuO (Me represents various metals), and Wittmer et al. lowered the sintering temperature of PZT to 960°C by adding V2O5. However, cadmium oxide is hazardous and requires special handling. Moreover, these solutions result in low mechanical quality factors and high dielectric loss factors in PZT ceramics, and there are no reports on their applicability to relaxor PZT ceramics. Since the quality factor is primarily dependent on the dielectric loss of the piezoelectric material, the choice of additives must take into account their practicality and effectiveness.

[0005] Geseman et al. tried to sinter the relaxor PMN-PZT ceramics at 1050℃ by using sintering additives such as ZnO and Bi2O3. Futakuchi et al. 1 / 3 Nb 2 / 3 )O3-PZT capacitors add excessive PbO to reduce the sintering temperature to 900°C and reduce the particle size to submicron, but greatly sacrifice the piezoelectric performance. Yan et al. developed a two-step sintering method for PNN-Pb(Hf,Ti)O3 ceramics by adding LiF to improve densification and piezoelectric properties, but still require 1100°C. In addition, Yi et al. developed CuO-LiBiO2 as a sintering aid to improve the sinterability and piezoelectric properties of PNN-PZT ceramics, but only reduced the temperature to 1000°C. KR20070091053A discloses a PZN-PZT material doped with MnO2, which improves the dielectric constant while reducing the sintering temperature. However, this technology is aimed at composite components containing PZN that are easy to sinter at low temperatures, and its technical superiority is only reflected after the PZN ratio is greater than 40%. Summary of the Invention

[0006] The purpose of the present invention is to address the deficiencies in the prior art and provide a piezoelectric ceramic composite material and a preparation method thereof, wherein the piezoelectric ceramic composite material can realize a low-temperature sintering scheme compatible with Ag electrodes and has a dielectric constant at least 2 times higher than that of traditional PZT ceramics sintered at similar low temperatures.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] The first aspect of the present invention is to provide a piezoelectric ceramic composite material having the chemical composition of: (1-x) Pb(Ni 1 / 3Nb 2 / 3 )O3- x Pb(ZrTi)O3-yMnO2-MeO z -Li2CO3-Bi2O3-Pb m O n ,

[0009] Among them, x is 0.4-0.99, which represents the Pb(ZrTi)O3 in Pb(Ni 1 / 3 Nb 2 / 3 )O3 – Pb(ZrTi)O3 molar ratio in the system;

[0010] The molar ratio of Zr / Ti is 30 / 70-60 / 40;

[0011] y is 0.01wt%-1wt%, which represents MnO2 in (1-x) Pb(Ni 1 / 3 Nb 2 / 3 )The weight percentage in the O3-xPb(ZrTi)O3-yMnO2 system.

[0012] Preferably, MeO z Any one or more of Fe2O3, Cr2O3, NiO, CdO, Pb m O n It is PbO or Pb3O4.

[0013] Preferably, in the piezoelectric ceramic composite material, the weight percentage of MeOz is 0wt%-2wt%, the weight percentage of Li2CO3 is 0.1wt%-2wt%, the weight percentage of Bi2O3 is 0.1wt%-2wt%, and the weight percentage of Pb m O n The weight percentage is 0.3wt%-3wt%.

[0014] A second aspect of the present invention is to provide a method for preparing the piezoelectric ceramic composite material, comprising the following steps:

[0015] S1, according to (1-x) Pb(Ni 1 / 3 Nb 2 / 3)O3- x Pb(ZrTi)O3-yMnO2 stoichiometric ratio of raw materials Pb3O4, ZrO2, TiO2, NiNb2O6 and MnO2 were weighed, ball-milled, dried, sieved and pre-calcined to prepare MnO2-doped PNN-PZT ceramics;

[0016] S2. Weigh a sintering agent according to weight percentage, mix it with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence, and then perform low-temperature sintering to obtain the piezoelectric ceramic composite material.

[0017] Preferably, the sintering agent includes: Pb m O n and MeO z , Li2CO3, Bi2O3.

[0018] Preferably, in step S1, the pre-calcination temperature is 825° C.-900° C., and the time is 3 h-5 h.

[0019] Preferably, in step S2, the temperature of the low-temperature sintering is 850°C-950°C and the time is 4h-8h. The present invention adopts the above technical solution, which has the following technical effects compared with the prior art:

[0020] The present invention utilizes MnO2, Pb m O n The synergistic effect of the additional sintering agent achieves low-temperature sintering, reducing the sintering temperature of the PNN-PZT piezoelectric ceramic composite material to below 950°C; and the piezoelectric ceramic composite material of the present invention has a higher dielectric constant and piezoelectric coefficient than traditional PZT ceramics within a wide range of PNN components, while taking into account a higher mechanical quality factor Qm and lower dielectric loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart for preparing the piezoelectric ceramics in a comparative example of the present invention;

[0022] Figure 2 FIG. 4 is a flow chart for preparing a piezoelectric ceramic composite material in one embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0025] The present invention will be further described below with reference to specific examples, but they are not intended to limit the present invention.

[0026] Example 1

[0027] This embodiment provides a method for preparing a piezoelectric ceramic composite material, such as Figure 2 As shown, the steps include:

[0028] S1, according to 0.1 Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.9 Pb(ZrTi)O3-0.3 MnO2 stoichiometric ratio of raw materials 68.38g PbO, 17.27g ZrO2, 11.01g TiO2, 3.5g NiNb2O6 and 0.3g MnO2 were weighed, ball-milled, dried, sieved and pre-calcined at 850℃ for 3h to prepare MnO2-doped PNN-PZT ceramics;

[0029] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3, 1.5 g of PbO, and 1.0 g of NiO by weight percentage, mix them with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence, and then sintering at 900°C for 4 h to obtain the piezoelectric ceramic composite material.

[0030] Example 2

[0031] This embodiment provides another method for preparing a piezoelectric ceramic composite material, the steps comprising:

[0032] S1, according to 0.2 Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.8 Pb(ZrTi)O3-0.3 MnO2 stoichiometric ratio of raw materials 68.48g PbO, 14.28g ZrO2, 10.47g TiO2, 6.99g NiNb2O6 and 0.3g MnO2 were weighed, ball-milled, dried, sieved and pre-calcined at 850℃ for 3h to prepare MnO2-doped PNN-PZT ceramics;

[0033] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3, and 2.0 g of PbO by weight, mix them with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence. Then, sinter at 900°C for 4 h to obtain the piezoelectric ceramic composite material.

[0034] Example 3

[0035] This embodiment provides another method for preparing a piezoelectric ceramic composite material, the steps comprising:

[0036] S1, according to 0.25 Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.75 Pb(ZrTi)O3-0.5 MnO2 stoichiometric ratio: 68.85 g PbO, 12.54 g ZrO2, 10.35 g TiO2, 8.75 g NiNb2O6, and 0.5 g MnO2 were weighed, ball-milled, dried, sieved, and pre-calcined at 850 ° C for 3 h to prepare MnO2-doped PNN-PZT ceramics;

[0037] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3, and 2.0 g of PbO by weight, mix them with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence. Then, sinter at 900°C for 4 h to obtain the piezoelectric ceramic composite material.

[0038] Example 4

[0039] This embodiment provides another method for preparing a piezoelectric ceramic composite material, the steps comprising:

[0040] S1, according to 0.32 Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.68 Pb(ZrTi)O3-0.5 MnO2 stoichiometric ratio of raw materials 68.39g PbO, 11.09g ZrO2, 9.56g TiO2, 11.17g NiNb2O6 and 0.5g MnO2 were weighed, ball-milled, dried, sieved and pre-calcined at 850℃ for 3h to prepare MnO2-doped PNN-PZT ceramics;

[0041] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3, 1.0 g of PbO, and 0.5 g of CdO by weight, mix them with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence. Then, sinter at 900°C for 4 h to obtain the piezoelectric ceramic composite material.

[0042] Example 5

[0043] This embodiment provides another method for preparing a piezoelectric ceramic composite material, the steps comprising:

[0044] S1, according to 0.36 Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.64 Pb(ZrTi)O3-0.5 MnO2 stoichiometric ratio of raw materials 34.93g PbO, 4.81XXg ZrO2, 4.88g TiO2, 6.39g NiNb2O6 and 0.5g MnO2 were weighed, ball-milled, dried, sieved, and pre-calcined at 850℃ for 3h to prepare MnO2-doped PNN-PZT ceramics;

[0045] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3, and 2.0 g of PbO by weight, mix them with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence. Then, sinter at 900°C for 4 h to obtain the piezoelectric ceramic composite material.

[0046] Example 6

[0047] This embodiment provides another method for preparing a piezoelectric ceramic composite material, the steps comprising:

[0048] S1, according to 0.45 Pb(Ni 1 / 3 Nb 2 / 3 )O3-0.55 Pb(ZrTi)O3-0.75 MnO2 stoichiometric ratio of raw materials 68.59g PbO, 7.71g ZrO2, 8.51g TiO2, 15.70g NiNb2O6 and 0.75g MnO2 were weighed, ball-milled, dried, sieved and pre-calcined at 850℃ for 3h to prepare MnO2-doped PNN-PZT ceramics;

[0049] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3, and 2.0 g of PbO by weight, mix them with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence. Then, sinter at 950°C for 8 h to obtain the piezoelectric ceramic composite material.

[0050] Example 7

[0051] This embodiment provides another method for preparing a piezoelectric ceramic composite material, the steps comprising:

[0052] S1, according to 0.5 Pb(Ni 1 / 3 Nb 2 / 3)O3-0.5 Pb(ZrTi)O3-0.75 MnO2 stoichiometric ratio of raw materials 68.73g PbO, 16.01g ZrO2, 10.83g TiO2, 4.89g NiNb2O6 and 0.75g MnO2 were weighed, ball-milled, dried, sieved and pre-calcined at 850℃ for 3h to prepare MnO2-doped PNN-PZT ceramics;

[0053] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3 and 2.0 g of PbO by weight percentage, mix them with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing and coating in sequence, and then sintering at 950°C for 4 hours to obtain the piezoelectric ceramic composite material.

[0054] Comparative Example 1

[0055] This comparative example provides another method for preparing a piezoelectric ceramic composite material, comprising the following steps:

[0056] S1. According to the stoichiometric ratio of Pb(ZrTi)O3-0.3 MnO2, 68.90 g PbO, 19.70 g ZrO2, 11.79 g TiO2, and 0.3 g MnO2 were weighed, ball-milled, dried, sieved, and pre-calcined at 850 °C for 3 h to obtain MnO2-doped PZT ceramics.

[0057] S2. PbO is weighed according to weight percentage, mixed with the MnO2-doped PZT ceramic prepared in step S1, and then ball-milled, dried, sieved, compacted, polished, and coated in sequence, and then sintered at 1250° C. for 2 h to obtain the piezoelectric ceramic composite material.

[0058] Comparative Example 2

[0059] This comparative example provides another method for preparing a piezoelectric ceramic composite material, comprising the following steps:

[0060] S1, same as comparative example 1;

[0061] S2. Weigh 0.5 g of Li2CO3, 0.5 g of Bi2O3, 1.0 g of PbO, 1.0 g of NiO, and 0.5 g of CdO by weight, mix them with the MnO2-doped PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence, and then sintering at 900°C for 4 h to obtain the piezoelectric ceramic composite material.

[0062] Comparative Example 3

[0063] This comparative example provides another method for preparing a piezoelectric ceramic composite material, comprising the following steps:

[0064] S1, same as Example 1;

[0065] S2. Weigh 0.5 g of PbO by weight, mix it with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing and coating in sequence, and then sintering at 1200° C. for 4 hours to obtain the piezoelectric ceramic composite material.

[0066] Comparative Example 4

[0067] This comparative example provides another method for preparing a piezoelectric ceramic composite material. Figure 1 As shown, the steps include:

[0068] S1, same as Example 1;

[0069] S2: No sintering additives are added, and the rest are the same as in Example 1.

[0070] Comparative Example 5

[0071] This comparative example provides another method for preparing a piezoelectric ceramic composite material, comprising the following steps:

[0072] S1, without adding MnO2, the rest are the same as Example 1;

[0073] S2. Same as Example 1.

[0074] Detection Example

[0075] The ceramics prepared by the preparation methods described in Examples 1-7 and Comparative Examples 1-5 were processed into particles with a size of 24 mm×1 mm, metallized with silver paste, and then fired at 860° C. for 1 hour.

[0076] The specific testing plan is as follows:

[0077] Polarization was performed at room temperature in silicone oil or 3M Fluorinert liquid (FC-40) under a DC field of >20 kV / cm.

[0078] Density is calculated based on physical geometry and mass.

[0079] The composite dielectric response was measured using a Novocontrol dielectric spectrometer at 1 kHz.

[0080] The electrical coupling factor and mechanical quality factor were calculated using a Keysight impedance analyzer using the resonance-antiresonance method.

[0081] The piezoelectric coefficient was measured using a d33 meter.

[0082] The results are shown in Table 1;

[0083] Table 1

[0084]

[0085] NOTE: The first number in the first column (e.g., 0.1 in 0.1-51 / 49-0.3MnO2) represents the molar ratio of PNN in PNN-PZT, the second and third numbers (e.g., 51 / 49 in 0.1-51 / 49-0.3MnO2) represent the Zr / Ti ratio, and the fourth number (e.g., 0.3 in 0.1-51 / 49-0.3MnO2) represents the wt% of MnO2 in PNN-PZT-MnO2. LB represents Li2CO3-Bi2O3 compound, Pb represents PbO, Cd represents CdO, and Ni represents NiO.

[0086] Compared with Examples 1-7, Comparative Examples 1-2, which do not contain PNN, exhibit lower dielectric constants and piezoelectric coefficients, indicating that the addition of PNN can simultaneously improve both dielectric constants and piezoelectric coefficients while lowering sintering temperatures. Furthermore, Comparative Example 1 failed to produce a ceramic at 900°C, resulting in low density and shrinkage, making polarization performance measurements impossible. Similarly, Comparative Example 3 exhibited very low density and shrinkage at 900°C, indicating poor performance. In other words, Comparative Examples 1 and 3 can only produce ceramics with good performance when sintered at high temperatures. Comparative Example 4 cannot achieve high density when sintered at low temperature, and Comparative Example 5 cannot achieve high density, high electromechanical coupling coefficient and mechanical quality factor when sintered at low temperature, and cannot reduce dielectric loss. Although the dielectric constant of Comparative Example 4-5 is high, the dielectric constant is due to the lower density of Comparative Example 4-5 and the external contribution of the interface dipole, not the intrinsic polarization contribution of the piezoelectric grains, that is, Comparative Example 4-5 does not actually have superiority; and the lack of MnO2 in Comparative Example 5 causes its quality factor to be significantly reduced; while the dielectric constants of the embodiments all reflect the true intrinsic polarization contribution of the crystals in the piezoelectric material, and their various performances are all excellent.

[0087] The present invention utilizes MnO2, Pb m O n The synergistic effect of the additional sintering agent achieves low-temperature sintering, reducing the sintering temperature of the piezoelectric ceramic composite material to below 950° C.; and the piezoelectric ceramic composite material of the present invention has a higher mechanical quality factor Qm, lower dielectric loss and a high dielectric constant.

[0088] The above description is only a preferred embodiment of the present invention and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A piezoelectric ceramic composite material, characterized in that: The chemical composition is: (1-x) Pb(Ni 1 / 3 Nb 2 / 3 )O3- x Pb(ZrTi)O3-yMnO2-MeO z -Li2CO3-Bi2O3-Pb m O n , Among them, x is 0.4-0.99, which represents the Pb(ZrTi)O3 in Pb(Ni 1 / 3 Nb 2 / 3 )O3 – Pb(ZrTi)O3 molar ratio in the system; The molar ratio of Zr / Ti is 30 / 70-60 / 40; y is 0.01wt%-1wt%, which represents MnO2 in (1-x) Pb(Ni 1 / 3 Nb 2 / 3 ) weight percentage in the O3-xPb(ZrTi)O3-yMnO2 system; The composition of the sintering agent is Pb m O n 、MeO z , Li2CO3, Bi2O3; MeO z At least one of Fe2O3, Cr2O3, NiO, CdO, Pb m O n PbO or Pb3O4; In the piezoelectric ceramic composite material, MeO z The weight percentage of Li2CO3 is 0wt%-2wt%, the weight percentage of Bi2O3 is 0.1wt%-2wt%, and the weight percentage of Pb m O n The weight percentage is 0.3wt%-3wt%.

2. A method for preparing the piezoelectric ceramic composite material according to claim 1, characterized in that the steps include: S1、According to (1-x) Pb(Ni 1 / 3 Nb 2 / 3 )O3- x Pb(ZrTi)O3-yMnO2 stoichiometric ratio of raw materials Pb3O4, ZrO2, TiO2, NiNb2O6 and MnO2 were weighed, ball-milled, dried, sieved and pre-calcined to prepare MnO2-doped PNN-PZT ceramics; S2. Weigh a sintering agent according to weight percentage, mix it with the MnO2-doped PNN-PZT ceramic prepared in step S1, and then perform ball milling, drying, screening, compacting, polishing, and coating in sequence, and then perform low-temperature sintering to obtain the piezoelectric ceramic composite material.

3. The preparation method according to claim 2, characterized in that In step S1, the pre-calcination temperature is 825° C.-900° C., and the time is 3 h-5 h.

4. The preparation method according to claim 2, characterized in that In step S2, the low-temperature sintering temperature is 850° C.-950° C., and the time is 4 h-8 h.

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