Ultrahigh-density pin-pyn-pt solid solution piezoelectric ceramic and preparation method thereof

Abstract

This invention discloses an ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic and its preparation method. The general chemical formula of the piezoelectric ceramic material used is: xPb(In) 0.5 Nb 0.5 )-yPb(Yb 0.5 Nb 0.5 The preparation process mainly includes: precursor synthesis, ball milling and mixing, adding PVA binder solution to dry PIN-PYN-PT ceramic powder, mixing thoroughly and then drying to obtain dry powder, pressing the dry powder into shape and removing the binder, sintering the obtained ceramic green body by hot isostatic pressing at 900-1000℃ and 20MPa-100MPa for 1-3 hours to obtain hot isostatic sintered PIN-PYN-PT piezoelectric ceramic; annealing and ceramic polarization of the obtained ceramic in an oxygen atmosphere at 800-1000℃ for 0.5-2h to obtain ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic, which has high piezoelectric and dielectric properties as well as a high phase transition temperature and a quasi-static piezoelectric constant d. 33 It reaches 620 pC / N, has a room temperature dielectric constant of 3100, and a Curie temperature of T. C The phase transition temperature reaches 350℃, T rt Up to 230℃, longitudinal coupling coefficient k 33 The thickness mechanical coupling coefficient k reaches 0.57. t It reached 0.57.

Description

Technical Field

[0001] This invention belongs to the field of piezoelectric ceramic materials technology, specifically relating to an ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic and its preparation method. Background Technology

[0002] High-performance piezoelectric ceramics possess excellent properties such as high piezoelectricity and high electromechanical coupling coefficient, bringing historic development opportunities to fields such as broadband, high-resolution, and high-sensitivity medical ultrasound imaging and underwater acoustic detection. They also have significant demand in areas such as public health, socio-economic development, and national security. Currently, 90% of the high-performance ceramic materials used in ceramic piezoelectric probes both domestically and internationally are from CTS Corporation in the United States, and another 10% are from TRS Corporation. my country currently relies 100% on imports for the piezoelectric materials used in high-performance medical ultrasound probes. Therefore, further independent development and production of domestically made high-performance piezoelectric ceramics is of great significance.

[0003] The fabrication and use of piezoelectric devices such as ultrasound probes, underwater acoustic detectors, and ultrasonic transducers involve many high-temperature processes, placing high demands on the operating temperature of piezoelectric materials, specifically requiring the ceramic materials used to have high phase transition temperatures. To ensure instrument accuracy, piezoelectric ceramics must also possess high and stable piezoelectric and dielectric properties. Currently, mainstream commercial piezoelectric ceramics, such as PMN-PT and PZT5A ceramics, have high piezoelectric properties, but their low phase transition temperatures lead to a significant performance degradation at high temperatures. While ceramics such as PZT8 have very high phase transition temperatures, their piezoelectric properties are relatively low (<300 pC / N), failing to adequately meet the demands of the high-end device market. Therefore, the development of piezoelectric ceramic materials that combine high phase transition temperatures and high piezoelectric properties has become a pressing technical challenge. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a PIN-PYN-PT piezoelectric ceramic with a high phase transition temperature and its preparation method. The chemical formula of the piezoelectric ceramic material is: xPb(In) 0.5 Nb 0.5 )-yPb(Yb 0.5 Nb 0.5 )-zPbTiO3, where 0.05≤x≤0.5, 0.2≤y≤0.8, and 0.05≤z≤0.5.

[0005] To achieve the above objectives, on the one hand, the present invention provides an ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic, characterized in that the general chemical formula of the PIN-PYN-PT solid solution piezoelectric ceramic used is: xPb(In 0.5 Nb 0.5 )-yPb(Yb 0.5 Nb0.5 )-zPbTiO3, where 0.05≤x≤0.5, 0.2≤y≤0.8, and 0.05≤z≤0.5.

[0006] On the other hand, the present invention provides a method for preparing ultra-high density PIN-PYN-PT solid solution piezoelectric ceramics as described above, comprising the following steps:

[0007] PbO, TiO2, InNbO4 precursor powder, and YbNbO4 precursor powder were weighed according to stoichiometric ratio, and then mixed by wet ball milling and direct drying to obtain a mixture.

[0008] The resulting mixture was pre-fired at 800-1000℃. The pre-fired product was mixed with ethanol, then dispersed and ball-milled twice, dried and sieved to obtain dry PIN-PYN-PT ceramic powder.

[0009] PVA binder solution is added to dry PIN-PYN-PT ceramic powder, mixed thoroughly and then dried to obtain dry powder. The dry powder is pressed into shape and held at 600℃-700℃ for 1-4 hours to remove the binder, thus obtaining ceramic green body.

[0010] The obtained ceramic green body was sintered by hot isostatic pressing (HIP) in an oxygen atmosphere at 900–1000 °C and 20 MPa–100 MPa for 1–3 hours to obtain HIP-PYN-PT piezoelectric ceramic.

[0011] The obtained samples were annealed at 800℃-1000℃ for 0.5-2h to obtain ultra-high density PIN-PYN-PT ceramics;

[0012] After coating both sides of the ultra-high density PIN-PYN-PT ceramic with silver electrodes, DC high voltage polarization was performed to obtain PIN-PYN-PT solid solution piezoelectric ceramic.

[0013] Furthermore, the preparation of the precursor InNbO4 powder includes: weighing analytically pure In2O3 and Nb2O5 according to the stoichiometric ratio, mixing them by wet ball milling, directly drying them, and calcining them in a high-temperature furnace at 900-1100℃ for 2-6 hours to obtain the precursor InNbO4 powder.

[0014] The preparation of precursor YbNbO4 powder includes: weighing analytically pure Yb2O3 and Nb2O5 according to stoichiometric ratio, mixing them by wet ball milling, directly drying them, and calcining them in a high-temperature furnace at 950-1050℃ for 3-8 hours to obtain precursor YbNbO4 powder.

[0015] Furthermore, the amount of PVA adhesive added is 2wt%-10wt%, and the PVA adhesive is a 10% PVA adhesive solution that has been plasticized with glycerol.

[0016] Furthermore, during hot isostatic pressing sintering, the oxygen atmosphere is formed by a mixture of high-purity argon and oxygen.

[0017] Furthermore, the purity of PbO and TiO2 was analytical grade.

[0018] Furthermore, during DC high-voltage polarization: the polarization temperature is 120℃, a polarization electric field of 30kV / cm is applied, and polarization treatment is performed for 30 minutes.

[0019] Furthermore, the obtained PIN-PYN-PT solid solution piezoelectric ceramic has a theoretical density of up to 99.9% and a quasi-static piezoelectric constant d. 33 The highest value is 620 pC / N, the highest dielectric constant at room temperature is 3100, and the Curie temperature is T. C The highest temperature is 350℃, and the phase transition temperature T is... rt The highest temperature is 230℃, and the longitudinal coupling coefficient k 33 The highest value is 0.57, k t The highest value is 0.57.

[0020] The present invention also provides a transducer piezoelectric device, which is a PIN-PYN-PT solid solution piezoelectric ceramic prepared by the above method.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] The ternary PIN-PYN-PT piezoelectric ceramic material disclosed in this invention possesses superior temperature stability and high piezoelectric and dielectric properties, with a quasi-static piezoelectric constant d. 33 It can reach 620 pC / N, the dielectric constant at room temperature can reach 3100, and the Curie temperature T C It can reach 350℃, and the phase transition temperature T rt Up to 230℃, longitudinal coupling coefficient k 33 It can reach 0.57, k t With a piezoelectric strength of up to 0.57, it can be used in ultrasound probes, ultrasonic transducers and other piezoelectric devices, and maintains high piezoelectric performance at high temperatures. The ceramic prepared by hot isostatic pressing of this invention has significantly superior density and electrical properties. Furthermore, sintering in an oxygen atmosphere can reduce oxygen vacancy defects in PIN-PYN-PT piezoelectric ceramics and improve the density of the ceramics.

[0023] Furthermore, this invention, through experimental comparison of purchased precursors InNbO4 and YbNbO4 with self-made precursors, clearly demonstrates that the self-made precursor exhibits better experimental results, yielding ceramic materials with significantly higher purity and superior electrical properties. This invention also determines the quasi-isomorphic phase boundary (MPB) ratio of ternary ultra-high density PIN-PYN-PT piezoelectric ceramics through a series of experiments, obtaining the optimal performance ratio. The preparation method of this invention has advantages such as simple operation, short cycle time, low cost, and ease of large-scale production. Attached Figure Description

[0024] Figure 1 The X-ray diffraction pattern of the PIN-PYN-PT piezoelectric ceramic of Embodiment 1 of the present invention;

[0025] Figure 2 This is a scanning electron microscope (SEM) image of the surface of the PIN-PYN-PT piezoelectric ceramic according to Embodiment 1 of the present invention;

[0026] Figure 3 This is the dielectric temperature spectrum of the PIN-PYN-PT piezoelectric ceramic material according to Embodiment 2 of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some examples of the present invention, and the content of the present invention includes all the contents described in the embodiments, but is not limited to the scope described. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art through simple substitutions and modifications to the content of the present invention without creative effort are within the protection scope of the present invention.

[0028] Example 1: An ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic was prepared using the following steps:

[0029] (1) In2O3 and Nb2O5 were weighed in sequence according to the stoichiometric ratio. The purity of the raw materials was In2O3≥99.9% and Nb2O5≥99.9%, respectively. They were mixed by wet ball milling, directly dried, and calcined in a high-temperature furnace at 900℃ for 2 hours to obtain the precursor InNbO4 powder.

[0030] (2) Weigh Yb2O3 and Nb2O5 in sequence according to the stoichiometric ratio. The purity of the raw materials is Yb2O3≥99.9% and Nb2O5≥99.9%, respectively. They are mixed by wet ball milling, directly dried, and calcined in a high-temperature furnace at 950°C for 3 hours to obtain precursor YbNbO4 powder.

[0031] (3) Weigh PbO, TiO2, InNbO4 and YbNbO4 in sequence according to the stoichiometric ratio. The purity of the raw materials is PbO≥99.9%, TiO2≥99.9%, InNbO4≥99.9% and YbNbO4≥99.9%, respectively. The specific ratio is: PbO is 30.1242g, TiO2 is 1.6007g, InNbO4 is 0.9076g and YbNbO4 is 17.6351g. Put the weighed raw materials into a ball mill jar. The mass ratio of raw materials, anhydrous ethanol and zirconium balls is approximately 1:0.8:6. Select zirconium oxide balls with a diameter of 3-10mm and ball mill for 12-24h. Dry the ceramic slurry in an oven to obtain dry powder. Put the dry powder into a crucible and keep it at 800℃ for 2h to obtain ceramic powder.

[0032] (4) The PIN-PYN-PT ceramic powder in step (3) is mixed with anhydrous ethanol and then dispersed and ground for a second time. The grinding method is ball milling for 12 hours to obtain ceramic slurry.

[0033] (5) The PIN-PYN-PT ceramic slurry in step (4) is directly dried to obtain a uniformly composed dry powder;

[0034] (6) The dried PIN-PYN-PT ceramic powder in step (5) is passed through a 60-mesh sieve, and then a glycerol-plasticized PVA adhesive solution with a concentration of 10% is added. The concentration of 10% means that the ratio of PVA to water is 1:9. The mixture is thoroughly mixed in a mixer to form a viscous premixed material. The amount of PVA adhesive added is 2wt%.

[0035] (7) The premixed material in step (6) is directly dried to obtain a uniformly composed dry powder;

[0036] (8) The dried PIN-PYN-PT ceramic powder in step (7) is passed through 80-mesh and 100-mesh sieves. The dried ceramic powder between 80-mesh and 100-mesh is taken and mechanically uniaxially pressed into shape. The powder is then kept at 600℃ for 1 hour to remove the binder and obtain a ceramic blank.

[0037] (9) The obtained ceramic blank is placed in a crucible and sintered by hot isostatic pressing. It is sintered for 1-3 hours in an oxygen atmosphere composed of oxygen and argon at 900℃ and 20MPa to obtain hot isostatic pressing PIN-PYN-PT piezoelectric ceramic.

[0038] (10) The obtained sample was annealed at 800℃ for 0.5h to obtain a ceramic sheet of a certain shape. The obtained ceramic grains were 5-10μm and the theoretical density was 99.9%.

[0039] (11) The PIN-PYN-PT piezoelectric ceramic obtained in step (10) is ground by a surface mill to obtain a ceramic sheet with the required roughness, flatness and thickness.

[0040] (12) The PIN-PYN-PT piezoelectric ceramic with silver electrodes on both sides obtained in step (11) is heated to 120°C and a polarization electric field of 30kV / cm is applied for high-temperature polarization for 30 minutes.

[0041] like Figure 1 As shown, the PIN-PYN-PT piezoelectric ceramic material of this invention has a pure perovskite structure. The grain morphology of the PIN-PYN-PT piezoelectric ceramic prepared by this invention was analyzed using field emission scanning electron microscopy, as shown below. Figure 2 As shown, the prepared PIN-PYN-PT piezoelectric ceramic has ultra-high density, and the ceramic grain size is about 5-10 μm.

[0042] Example 2: An ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic was prepared using the following steps:

[0043] (1) In2O3 and Nb2O5 were weighed in sequence according to the stoichiometric ratio. The purity of the raw materials was In2O3≥99.9% and Nb2O5≥99.9%, respectively. They were mixed by wet ball milling, directly dried, and calcined in a high-temperature furnace at 950°C for 2 hours to obtain the precursor InNbO4 powder.

[0044] (2) Weigh Yb2O3 and Nb2O5 in sequence according to the stoichiometric ratio. The purity of the raw materials is Yb2O3≥99.9% and Nb2O5≥99.9%, respectively. They are mixed by wet ball milling, directly dried, and calcined in a high-temperature furnace at 1000℃ for 6 hours to obtain precursor YbNbO4 powder.

[0045] (3) Weigh PbO, TiO2, InNbO4 and YbNbO4 in sequence according to the stoichiometric ratio. The purity of the raw materials is PbO≥99.9%, TiO2≥99.9%, InNbO4≥99.9% and YbNbO4≥99.9%, respectively. The specific ratio is: PbO is 30.5128g, TiO2 is 0.5404g, InNbO4 is 9.1935g and YbNbO4 is 10.0477g. Put the weighed raw materials into a ball mill jar. The mass ratio of raw materials, anhydrous ethanol and zirconium balls is approximately 1:0.8:6. Select zirconium oxide balls with a diameter of 3-10mm and ball mill for 12-24h. Dry the ceramic slurry in an oven to obtain dry powder. Put the dry powder into a crucible and keep it at 850℃ for 2h to obtain ceramic powder.

[0046] (4) The PIN-PYN-PT ceramic powder in step (3) is mixed with anhydrous ethanol and then dispersed and ground for a second time. The grinding method is ball milling for 16 hours to obtain ceramic slurry.

[0047] (5) The PIN-PYN-PT ceramic slurry in step (4) is directly dried to obtain a uniformly composed dry powder;

[0048] (6) The dried PIN-PYN-PT ceramic powder in step (5) is passed through a 60-mesh sieve, and then a glycerol-plasticized PVA adhesive solution with a concentration of 10% is added. The concentration of 10% means that the ratio of PVA to water is 1:9. The mixture is thoroughly mixed in a mixer to form a premixed material with a certain viscosity. The amount of PVA adhesive added is 5wt%.

[0049] (7) The premixed material in step (6) is directly dried to obtain a uniformly composed dry powder;

[0050] (8) The dried PIN-PYN-PT ceramic powder in step (7) is passed through 80-mesh and 100-mesh sieves. The dried ceramic powder between 80-mesh and 100-mesh is taken and the obtained ceramic powder is pressed into shape by a combination of mechanical uniaxial pressing and cold isostatic pressing. The binder is removed by keeping it at 650℃ for 2 hours to obtain the ceramic blank.

[0051] (9) The obtained ceramic blank is placed in a crucible and sintered by hot isostatic pressing. It is sintered for 1.5 hours in an oxygen atmosphere composed of oxygen and argon at 950℃ and 40MPa to obtain hot isostatic pressing PIN-PYN-PT piezoelectric ceramic.

[0052] (10) The obtained sample was annealed at 850℃ for 1 hour to obtain the high-performance PIN-PYN-PT piezoelectric ceramic.

[0053] (11) The PIN-PYN-PT piezoelectric ceramic obtained in step (10) is ground by a surface mill to obtain a ceramic sheet with the required roughness, flatness and thickness.

[0054] (12) The PIN-PYN-PT piezoelectric ceramic with silver electrodes on both sides obtained in step (11) is heated to 120°C and a polarization electric field of 30kV / cm is applied for high-temperature polarization for 30 minutes.

[0055] Example 3: An ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic, prepared by the following steps:

[0056] (1) In2O3 and Nb2O5 were weighed in sequence according to the stoichiometric ratio. The purity of the raw materials was In2O3≥99.9% and Nb2O5≥99.9%, respectively. They were mixed by wet ball milling, directly dried, and calcined in a high-temperature furnace at 1100℃ for 6 hours to obtain the precursor InNbO4 powder.

[0057] (2) Weigh Yb2O3 and Nb2O5 in sequence according to the stoichiometric ratio. The purity of the raw materials is Yb2O3≥99.9% and Nb2O5≥99.9%, respectively. They are mixed by wet ball milling, directly dried, and calcined in a high-temperature furnace at 1050℃ for 8 hours to obtain precursor YbNbO4 powder.

[0058] (3) Weigh PbO, TiO2, InNbO4, and YbNbO4 in sequence according to the stoichiometric ratio. The purity of the raw materials is PbO≥99.9%, TiO2≥99.9%, InNbO4≥99.9%, and YbNbO4≥99.9%, respectively. The specific ratio is: PbO is 33.3712g, TiO2 is 5.9109g, InNbO4 is 6.0328g, and YbNbO4 is 4.8839g. Put the weighed raw materials into a ball mill jar. The mass ratio of raw materials, anhydrous ethanol, and zirconium balls is approximately 1:0.8:6. Select zirconium oxide balls with a diameter of 3-10mm and ball mill for 16h. Dry the ceramic slurry in an oven to obtain dry powder. Put the dry powder into a crucible and keep it at 1000℃ for 2h to obtain ceramic powder.

[0059] (4) The PIN-PYN-PT ceramic powder in step (3) is mixed with anhydrous ethanol and then dispersed and ground for a second time. The grinding method is ball milling for 16 hours to obtain ceramic slurry.

[0060] (5) The PIN-PYN-PT ceramic slurry in step (4) is directly dried to obtain a uniformly composed dry powder;

[0061] (6) The dried PIN-PYN-PT ceramic powder in step (5) is passed through an 80-mesh sieve, and then a glycerol-plasticized PVA adhesive solution with a concentration of 10% is added. The concentration of 10% means that the ratio of PVA to water is 1:9. The mixture is thoroughly mixed in a mixer to form a premixed material with a certain viscosity. The amount of PVA adhesive added is 10wt%.

[0062] (7) The premixed material in step (6) is directly dried to obtain a uniformly composed dry powder;

[0063] (8) The dried PIN-PYN-PT ceramic powder in step (7) is passed through 100-mesh and 120-mesh sieves. The dried ceramic powder between 100-mesh and 120-mesh is taken and the obtained ceramic powder is pressed into shape by cold isostatic pressing. The binder is removed by keeping it at 680℃ for 3 hours to obtain the ceramic blank.

[0064] (9) The obtained ceramic blank was sintered by hot isostatic pressing. It was sintered for 2 hours in an oxygen atmosphere composed of oxygen and argon at 980°C and 60MPa to obtain hot isostatic pressing PIN-PYN-PT piezoelectric ceramic.

[0065] (10) The obtained sample was annealed at 950℃ for 1.5h to obtain the high-performance PIN-PYN-PT piezoelectric ceramic.

[0066] (11) The PIN-PYN-PT piezoelectric ceramic obtained in step (10) is ground by a surface mill to obtain a ceramic sheet with the required roughness, flatness and thickness.

[0067] (12) The PIN-PYN-PT piezoelectric ceramic with silver electrodes on both sides obtained in step (11) is heated to 120°C and a polarization electric field of 30kV / cm is applied for high-temperature polarization for 30 minutes.

[0068] Example 4: An ultra-high density PIN-PYN-PT solid solution piezoelectric ceramic, prepared using the following steps:

[0069] (1) In2O3 and Nb2O5 were weighed in sequence according to the stoichiometric ratio. The purity of the raw materials was In2O3≥99.9% and Nb2O5≥99.9%, respectively. They were mixed by wet ball milling, dried directly, and calcined in a high-temperature furnace at 1100℃ for 4 hours to obtain the precursor InNbO4 powder.

[0070] (2) Weigh Yb2O3 and Nb2O5 in sequence according to the stoichiometric ratio. The purity of the raw materials is Yb2O3≥99.9% and Nb2O5≥99.9%, respectively. They are mixed by wet ball milling, directly dried, and calcined in a high-temperature furnace at 1000℃ for 5 hours to obtain precursor YbNbO4 powder.

[0071] (3) Weigh PbO, TiO2, InNbO4, and YbNbO4 in sequence according to the stoichiometric ratio. The purity of the raw materials is PbO≥99.9%, TiO2≥99.9%, InNbO4≥99.9%, and YbNbO4≥99.9%, respectively. The specific ratio is: PbO is 33.3712g, TiO2 is 5.9109g, InNbO4 is 6.0328g, and YbNbO4 is 4.8839g. Put the weighed raw materials into a ball mill jar. The mass ratio of raw materials, anhydrous ethanol, and zirconium balls is approximately 1:0.8:6. Select zirconium oxide balls with a diameter of 3-10mm and ball mill for 16h. Dry the ceramic slurry in an oven to obtain dry powder. Put the dry powder into a crucible and keep it at 950℃ for 2h to obtain ceramic powder.

[0072] (4) The PIN-PYN-PT ceramic powder in step (3) is mixed with anhydrous ethanol and then dispersed and ground for a second time. The grinding method is ball milling for 24 hours to obtain ceramic slurry.

[0073] (5) The PIN-PYN-PT ceramic slurry in step (4) is directly dried to obtain a uniformly composed dry powder;

[0074] (6) The dried PIN-PYN-PT ceramic powder in step (5) is passed through an 80-mesh sieve, and then a glycerol-plasticized PVA adhesive solution with a concentration of 10% is added. The concentration of 10% means that the ratio of PVA to water is 1:9. The mixture is thoroughly mixed in a mixer to form a premixed material with a certain viscosity. The amount of PVA adhesive added is 10wt%.

[0075] (7) The premixed material in step (6) is directly dried to obtain a uniformly composed dry powder;

[0076] (8) The dried PIN-PYN-PT ceramic powder in step (7) is passed through 100-mesh and 120-mesh sieves. The dried ceramic powder between 100-mesh and 120-mesh is taken and the obtained ceramic powder is pressed into shape by cold isostatic pressing. The binder is removed by keeping it at 700℃ for 4 hours to obtain the ceramic blank.

[0077] (9) The obtained ceramic blank is placed in a crucible and sintered by hot isostatic pressing. It is sintered for 3 hours in an oxygen atmosphere composed of oxygen and argon at 1000℃ and 100MPa to obtain hot isostatic pressing PIN-PYN-PT piezoelectric ceramic.

[0078] (10) The obtained sample was annealed at 1000℃ for 2 hours to obtain the high-performance PIN-PYN-PT piezoelectric ceramic.

[0079] (11) The PIN-PYN-PT piezoelectric ceramic obtained in step (10) is ground by a surface mill to obtain a ceramic sheet with the required roughness, flatness and thickness.

[0080] (12) The PIN-PYN-PT piezoelectric ceramic with silver electrodes on both sides obtained in step (11) is heated to 120°C and a polarization electric field of 30kV / cm is applied for high-temperature polarization for 30 minutes.

[0081] This invention utilizes hot isostatic pressing (HIP) sintering in a high-purity argon-oxygen mixture atmosphere. HIP refers to subjecting a sample to uniform pressure in all directions during sintering under high temperature and pressure, resulting in ultra-high density. Compared to traditional hot pressing, HIP avoids the uneven stress distribution caused by unidirectional pressure and effectively solves the problem of ceramic product shapes and sizes being limited by pressing molds, thus expanding the methods of ceramic preparation and the range of ceramic product specifications. HIP ensures that the material achieves uniform density almost comparable to theoretical density, significantly reducing porosity and thus significantly optimizing the overall performance of the material. By reducing internal defects and porosity, the fatigue performance of materials is effectively improved, while significantly enhancing their toughness, ductility, and impact strength, enabling products to maintain excellent stability and durability even under extreme conditions. It promotes the formation of fine-grained, uniformly distributed microstructures in hard materials such as ceramics. This fine structure enhances the mechanical properties of the material. For powder materials that are difficult to compact using traditional methods, hot isostatic pressing (HIP) can serve as an efficient and reliable densification method, allowing these materials to achieve a high-density ideal state. HIP can directly manufacture products close to their final shape, greatly reducing subsequent processing steps and material waste, thus improving production efficiency and resource utilization. During the sintering process, this invention uses a high-purity argon-oxygen mixture with a 5%-10% oxygen content. Argon, as an inert gas, primarily acts as a protective gas, preventing unnecessary chemical reactions between the material and atmospheric oxygen or other impurities during sintering, thereby maintaining the purity and quality of the material. Simultaneously, the use of argon helps control the atmosphere during sintering, avoiding other unnecessary chemical reactions. Furthermore, the addition of oxygen can intensify the reaction between oxygen and substances, improving the heat treatment effect. Calcination in an oxygen atmosphere allows for oxidation reactions with organic matter or impurities in the material, removing impurities and purifying the material. Furthermore, oxygen can undergo high-temperature oxidation reactions with the material to form oxides, improving its thermal stability and oxidation resistance. The addition of oxygen helps improve the physical and chemical properties of the material.

[0082] Figure 3The dielectric temperature spectrum of the PIN-PYN-PT piezoelectric ceramic material of this invention is presented. Dielectric properties were measured using an automatic LCR meter at a frequency of 1 kHz, with a temperature range of 50°C to 450°C. The figure shows that the PIN-PYN-PT piezoelectric ceramic has a theoretical density of up to 99.9%, a room-temperature dielectric constant of 3100, and a Curie temperature (Tc) of 350°C. The piezoelectric coefficient of the PIN-PYN-PT piezoelectric ceramic material of this invention was measured using a quasi-static d33 meter, and the piezoelectric coefficient reached 720 pC / N.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing ultra-high density PIN-PYN-PT solid solution piezoelectric ceramics, characterized in that, The general chemical formula of the PIN-PYN-PT solid solution piezoelectric ceramic is: xPb(In 0.5 Nb 0.5 )-yPb(Yb 0.5 Nb 0.5 The preparation method of 0.05≤x≤0.5, 0.2≤y≤0.8, and 0.05≤z≤0.5 includes the following steps: PbO, TiO2, InNbO4 precursor powder, and YbNbO4 precursor powder were weighed according to stoichiometric ratio, and then mixed by wet ball milling and direct drying to obtain a mixture. The resulting mixture was pre-fired at 800-1000℃. The pre-fired product was mixed with ethanol, then dispersed and ball-milled twice, dried and sieved to obtain dry PIN-PYN-PT ceramic powder. PVA binder solution is added to dry PIN-PYN-PT ceramic powder, mixed thoroughly and then dried to obtain dry powder. The dry powder is pressed into shape and held at 600℃-700℃ for 1-4 hours to remove the binder, thus obtaining ceramic green body. The obtained ceramic green body was sintered by hot isostatic pressing (HIP) in an oxygen atmosphere at 900–1000 °C and 20 MPa–100 MPa for 1–3 hours to obtain HIP-PYN-PT ceramic. The obtained samples were annealed at 800℃-1000℃ for 0.5-2h to obtain ultra-high density PIN-PYN-PT ceramics; By coating both sides of ultra-high density PIN-PYN-PT ceramic with silver electrodes and then subjecting it to DC high-voltage polarization, PIN-PYN-PT solid solution piezoelectric ceramics were obtained. The resulting PIN-PYN-PT solid solution piezoelectric ceramics exhibited the highest theoretical density of 99.9%, the highest quasi-static piezoelectric constant d33 of 620 pC / N, the highest room-temperature dielectric constant of 3100, and a highest Curie temperature Ti. C The highest temperature is 350℃, and the phase transition temperature T is... rt The highest temperature is 230℃, and the longitudinal coupling coefficient k 33 The highest value is 0.57, k t The highest is 0.57; During hot isostatic pressing sintering, the oxygen atmosphere is formed by a mixture of high-purity argon and oxygen. DC high voltage polarization: polarization temperature 120℃, apply a polarization electric field of 30kV / cm, and perform polarization treatment for 30 minutes.

2. The method for preparing ultra-high density PIN-PYN-PT solid solution piezoelectric ceramics according to claim 1, characterized in that, The preparation of precursor InNbO4 powder includes: weighing analytical grade In2O3 and Nb2O5 according to stoichiometric ratio, mixing them by wet ball milling, directly drying them, and calcining them in a high-temperature furnace at 900-1100℃ for 2-6 hours to obtain precursor InNbO4 powder. The preparation of precursor YbNbO4 powder includes: weighing analytically pure Yb2O3 and Nb2O5 according to stoichiometric ratio, mixing them by wet ball milling, directly drying them, and calcining them in a high-temperature furnace at 950-1050℃ for 3-8 hours to obtain precursor YbNbO4 powder.

3. The method for preparing ultra-high density PIN-PYN-PT solid solution piezoelectric ceramics according to claim 1, characterized in that, The amount of PVA adhesive added is 2wt%-10wt%, and the PVA adhesive is a 10% PVA adhesive solution that has been plasticized with glycerol.

4. The method for preparing ultra-high density PIN-PYN-PT solid solution piezoelectric ceramics according to claim 1, characterized in that, The powder forming method is one or a combination of mechanical uniaxial pressing or cold isostatic pressing.

5. The method for preparing ultra-high density PIN-PYN-PT solid solution piezoelectric ceramics according to claim 1, characterized in that, The purity of PbO and TiO2 is analytical grade.

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