High-density LiNbO3 target material, preparation method, piezoelectric coating and application thereof

Abstract

The application discloses a high-density LiNbO3 target material, a preparation method, a piezoelectric coating and application of the high-density LiNbO3 target material, and the preparation method comprises the following steps: mixing Li2CO3, Nb2O5 and Li2O, and then performing compression molding to obtain a green body; and performing heat treatment on the green body to obtain the LiNbO3 target material. The Li2CO3 and the Nb2O5 are used, a sintering aid Li2O is introduced, the green body is obtained through compression molding, and then the high-density LiNbO3 target material is obtained through heat treatment, and the density of the high-density LiNbO3 target material is up to 4.62-4.64 g / cm 3 The LiNbO3 target material can be used to prepare a single-phase LiNbO3 piezoelectric coating through a sputtering method, and the LiNbO3 piezoelectric coating has a relatively high piezoelectric constant.

Description

Technical Field

[0001] This invention relates to the field of LiNbO3 piezoelectric materials and smart sensor technology, and particularly to a high-density LiNbO3 target, its preparation method, piezoelectric coating and its application. Background Technology

[0002] Lithium niobate is a trigonal ferroelectric material with excellent photorefractive, piezoelectric, thermoelectric, acousto-optic, electro-optic, and nonlinear optical effects. It has wide applications in holographic storage, piezoelectric sensors, thermoelectric sensors, acousto-optic modulators, electro-optic modulators, Q-switches in lasers, optical parametric oscillators, and optical waveguides. However, the basic materials for synthesizing LiNbO3, Li2O and Nb2O5, can also form three other compounds: Li3NbO4, LiNb3O8, and Li2Nb. 28 O 71 The Li3NbO4 phase is called lithium niobate or lithium ortho-niobate, while LiNbO3 is called lithium meta-niobate. Due to crystal preparation and material properties, only the LiNbO3 phase has piezoelectric properties.

[0003] During target preparation, LiNb3O8 impurities are easily introduced, making it impossible to prepare pure LiNbO3 targets. Furthermore, during thin film deposition, lithium-deficient LiNb3O8 phases can easily form in the LiNbO3 piezoelectric coating. Some methods address this issue using elemental doping. For example, CN119144930A provides a high-purity light metal-doped LiNbO3 piezoelectric coating and its preparation method. By doping with specific amounts and types of metal elements, a high-purity LiNbO3 piezoelectric coating free of lithium-deficient LiNb3O8 phases, as well as impurity phases such as NbO and Nb2O5, can be deposited. However, doping is inherently difficult to control, as the ionization rates of different elements vary. Light metals, in particular, are highly susceptible to secondary sputtering of the thin film by Ar ions, leading to differences in elemental content between the thin film and the target.

[0004] Therefore, under the limitations of sputtering technology, optimizing the preparation method of LiNbO3 target material to improve the piezoelectric properties of LiNbO3 piezoelectric coating is of positive significance for expanding the application of LiNbO3 piezoelectric coating in fields such as smart sensors, intelligent sensing and control devices. Summary of the Invention

[0005] To overcome the problems existing in the prior art, the present invention provides a method for preparing a high-density LiNbO3 target, comprising,

[0006] Li2CO3, Nb2O5 and Li2O are mixed and pressed into a blank to obtain a green body;

[0007] The green body is heat treated to obtain a high-density LiNbO3 target.

[0008] Further, the Li2CO3, Nb2O5 and Li2O are respectively subjected to water removal and preheating treatment before mixing.

[0009] The Li2CO3 and Nb2O5 are mixed in a molar ratio of 1:1 of Li and Nb, and the molar ratio of Nb2O5 to Li2O is 8-10:0.5-1.5.

[0010] Preferably, the water removal treatment can keep the Li2CO3, Nb2O5 and Li2O at 100℃ for 100h before mixing.

[0011] Further, the preheating treatment is carried out in multiple stages at 300-900℃, wherein the temperature and time of the next stage are higher than those of the previous stage.

[0012] Preferably, the preheating treatment is carried out in three stages at 400℃, 600℃ and 800℃ for 5h, 10h and 20h, respectively.

[0013] Preferably, before pressing, the Li2CO3, Nb2O5 and Li2O are mixed by ball milling, then dried and passed through a 300-500 mesh screen to obtain fine powder, and the fine powder is heat treated at 100-500℃, which is carried out in multiple stages, wherein the temperature of the next stage is lower than that of the previous stage, but the time of the next stage is longer than that of the previous stage. Specifically, the ball milling process is as follows: the Li2CO3, Nb2O5 and Li2O are mixed with anhydrous ethanol or deionized water and put into a ball milling tank, zirconia balls are used for grinding for 10-20 hours, the ball milling speed is 200-300 rpm for the first 5-10 hours and 300-500 rpm for the last 5-10 hours; after drying, the fine powder is obtained by passing through a 300-500 mesh screen.

[0014] Preferably, the heat treatment of the fine powder is carried out at 400-500℃, 200-400℃ and 100-200℃ for 1-2h, 2-4h and 10-14h, respectively.

[0015] Further, the purity of the Li2CO3, Nb2O5 and Li2O is higher than 99.99%, and the particle size is less than 800nm.

[0016] The pressing is carried out at a pressure of 200-500MPa for 5-10h. By prolonging the pressing time, internal pores are eliminated again and the inter-particle voids are reduced.

[0017] Preferably, the pressing is realized by isostatic pressing using corresponding moulds. In order to avoid density unevenness in the plane direction, each time the pre-billet with thickness of 2mm is pressed, and finally a plurality of pre-billets are combined and pressed into the billet. The specific thickness and shape of the billet can be selected according to the requirement of the target material of the actual magnetron sputtering equipment, and is not strictly limited. Exemplarily, the billet can be a cylinder with height of 4-6mm and diameter of 145mm-195mm.

[0018] Further, the sintering process is carried out on the billet, and the sintering process is carried out in multiple stages at 500-1300℃, wherein the temperature and time of the next stage of heat treatment are lower than the previous stage.

[0019] Preferably, the sintering process is carried out in three stages, respectively at 1000-1300℃, 600-800℃ and 300-500℃ for 1-2h, 2-4h and 10-14h.

[0020] Preferably, after the sintering process of the billet, a slow cooling process is carried out, and the cooling rate is 5-10℃ / min to avoid cracking caused by thermal stress.

[0021] Preferably, after the cooling process, a polishing process is also carried out on the surface of the product to ensure that the obtained LiNbO3 target material surface is smooth.

[0022] The application also provides a high-density LiNbO3 target material obtained by the above preparation method. The density of the prepared high-density lithium niobate target material is between 4.62-4.64g / cm 3 (The theoretical density of lithium niobate single crystal is 4.64g / cm³)

[0023] The application also provides a preparation method of LiNbO3 piezoelectric coating, which is prepared on the surface of a substrate by magnetron sputtering method using the above high-density LiNbO3 target material.

[0024] The magnetron sputtering method includes pre-sputtering, ultra-low oxygen pressure sputtering and low oxygen pressure sputtering.

[0025] Further, the parameters of the target pre-sputtering are as follows: radio frequency power 800-1200W, total gas pressure of Ar and O2 0.5-1.5Pa, Ar / O2 gas flow ratio 2.5-6.2 / 1, temperature 150-250℃, time 5-15min; during the pre-sputtering of the target, the substrate is placed away from the target, the target is pre-sputtered, and the surface oxide layer of the target is fully removed;

[0026] The parameters of the ultra-low oxygen pressure sputtering are as follows: radio frequency power 800-1200W, total gas pressure of Ar and O2 0.5-1.5Pa, Ar / O2 gas flow ratio 4.2 / 1-8.2 / 1, substrate temperature 320-390℃, target base distance 4.2-5.5cm, and film plating time 3-6h; since a small amount of O2 exists in the cavity at the initial stage of film plating, the input oxygen partial pressure should be reduced at this time.

[0027] The parameters of the low oxygen pressure sputtering are as follows: radio frequency power 800-1200W, total gas pressure of Ar and O2 0.5-1.5Pa, Ar / O2 gas flow ratio 3.5 / 1-4.2 / 1, substrate temperature 320-390℃, target base distance 4.2-5.5cm, and film plating time 3-6h.

[0028] In the present application, the material and morphology of the substrate are not strictly limited, and can be silicon wafer, stainless steel sheet, bolt and the like. Preferably, before sputtering film plating is performed on the substrate, the substrate is subjected to etching, polishing and the like to remove the oxide film, preferably ion etching can be used to sufficiently remove the surface layer oxide film of the substrate, and the specific parameters are as follows: total Ar gas pressure 0.5Pa-1.0Pa, voltage 150-250V, duty cycle 40-90%, current 0.32-1.21A, and etching time 30-60min.

[0029] The present application also provides a LiNbO3 piezoelectric coating prepared by the above preparation method.

[0030] The present application also provides application of the above LiNbO3 piezoelectric coating in the sensing field.

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] The present application provides a preparation method of high-density lithium niobate target material, which improves the density of the target material to 4.62-4.64g / cm 3 .

[0033] The present application uses Li2CO3 and Nb2O5, and obtains a high-density LiNbO3 target material by introducing a sintering aid Li2O to press a green body and then heat treating, and the LiNbO3 target material can prepare a single-phase LiNbO3 piezoelectric coating by sputtering method, and the LiNbO3 piezoelectric coating has a high piezoelectric constant. BRIEF DESCRIPTION OF DRAWINGS

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 The XRD pattern of the piezoelectric coating prepared in Example 1 is shown;

[0036] Figure 2 The XRD pattern of the piezoelectric coating prepared in Comparative Example 1 is shown.

[0037] Figure 3 The ultrasonic signal and piezoelectric constant diagram of the piezoelectric coating prepared in Example 1 are shown.

[0038] Figure 4 The ultrasonic signal and piezoelectric constant of the piezoelectric coating prepared in Comparative Example 1 are shown.

[0039] Figure 5 The XRD pattern of the piezoelectric coating prepared in Example 2 is shown;

[0040] Figure 6 The ultrasonic signal and piezoelectric constant of the piezoelectric coating prepared in Example 2 during continuous annealing at 700°C are shown.

[0041] Figure 7 The ultrasonic signal diagram of the piezoelectric coating prepared in Example 3 during continuous annealing at 700°C is shown.

[0042] Figure 8 The piezoelectric constant diagrams of the piezoelectric coating prepared in Example 3 after annealing at 700°C for 0h, 50h, and 100h are shown.

[0043] Figure 9 The ultrasonic signal diagrams of the piezoelectric coating prepared in Example 3 after annealing at 700°C for 0h, 50h, and 100h are shown. Detailed Implementation

[0044] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0045] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with specific embodiments of the present application and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0046] Embodiment 1

[0047] A preparation method of a high-density LiNbO3 piezoelectric coating, comprising the following steps,

[0048] 1. Preparation of high-density LiNbO3 target material

[0049] (1) Raw material preparation and pretreatment: Li2CO3, Nb2O5 and sintering aid Li2O with a purity of 99.99% and a particle size of 600 nm were dried at 100 ℃ for 100 h to remove water in Li2CO3, Nb2O5 and Li2O. Then, the dried Li2CO3, Nb2O5 and Li2O were pretreated at 400 ℃, 600 ℃ and 800 ℃ for 5 h, 10 h and 20 h, respectively, to remove impurities and improve crystallinity.

[0050] (2) Raw material mixing: Li2CO3 and Nb2O5 treated in step (1) were weighed according to the molar ratio (Li:Nb=1:1), and Nb2O5 and sintering aid Li2O were put into a ball mill at a molar ratio of 10:1.2, and anhydrous ethanol was added, and zirconia balls were used for grinding for 15 hours, at a speed of 200 rpm for the first 7 hours and at a speed of 500 rpm for the last 8 hours; after drying, the powder was sieved through a 400-mesh sieve to obtain fine powder.

[0051] (3) Fine powder heat treatment: the fine powder obtained in the previous step was heat treated at 400 ℃, 300 ℃ and 200 ℃ for 2 h, 4 h and 14 h, respectively.

[0052] (4) Target forming: a die was used to press a green body with a diameter of 145 mm and a thickness of 4 mm by isostatic pressing, the pressing pressure was increased to 400 MPa, and the pressing time was prolonged to 10 h, to further eliminate internal pores and reduce inter-particle voids. A layered pressing method was adopted, i.e., 2 mm thick target material was pressed each time, and finally the whole target was pressed by combining, to avoid density unevenness in the plane direction.

[0053] (5) Target sintering: Sintering process was carried out under N2 protection atmosphere (to prevent lithium niobate from decomposing), to promote grain growth and densification. Three-step sintering method was adopted, first high-temperature rapid sintering at 1100°C for 2h, then middle-temperature sintering at 800°C for 4h, and finally low-temperature long-time holding at 500°C for 12h to inhibit excessive grain growth.

[0054] (6) Cooling: The sintered body was cooled at a cooling rate of 8°C / min.

[0055] (7) Surface treatment: The cooled body was polished to ensure a smooth surface, and a high-density LiNbO3 target was obtained, with a mass of 305.49g and a calculated density of up to 4.625g / cm 3 , which is very close to the theoretical density of lithium niobate single crystal.

[0056] 2. Preparation of LiNbO3 piezoelectric coating

[0057] (1) Substrate pretreatment: A stainless steel sheet was used as the substrate, and ion etching was performed on the stainless steel sheet to thoroughly remove the surface oxide film. The etching parameters were as follows: total Ar gas pressure 0.6 Pa, voltage 200 V, duty cycle 50%, current 0.8 A, and etching time 40 min.

[0058] (2) Target pre-sputtering: The high-density LiNbO3 target was pre-sputtered (with the substrate placed away from the target), and the surface oxide layer was thoroughly removed. The sputtering parameters were as follows: RF power 900 W, total Ar and O2 gas pressure 0.9 Pa, Ar / O2 gas flow ratio 4 / 1, temperature 150°C, and time 5 min.

[0059] (3) Ultra-low oxygen pressure sputtering: The substrate was rotated to face the target, and the distance between the center of the substrate and the center of the target was adjusted. The radial distance was 0, indicating that the centers of the substrate and the target were coincident. A direction was defined, and the larger the radial distance, the farther the centers of the substrate and the target were offset. The radial distance was adjusted from -7 cm to 7 cm, and sputtering was performed. The sputtering parameters were as follows: RF power 900 W, total Ar and O2 gas pressure 0.9 Pa, Ar / O2 gas flow ratio 4.25 / 1, substrate temperature 340°C, target-substrate distance 4.3 cm, and time 4h. Due to the presence of a small amount of O2 in the chamber at the initial stage of sputtering growth, the input oxygen partial pressure should be reduced.

[0060] (4) Low oxygen pressure sputtering: The deposition parameters were adjusted, and sputtering growth was continued. The sputtering parameters were as follows: RF power 900 W, total Ar and O2 gas pressure 0.9 Pa, Ar / O2 gas flow ratio 3.8 / 1, substrate temperature 340°C, target-substrate distance 5.0 cm, and time 4h.

[0061] Example 2

[0062] The same as example 1, except that the target-to-substrate distance in the ultra-low oxygen pressure sputtering and the low oxygen pressure sputtering is 5.1 cm, and the adjusted radial distance is 0 and 4 cm.

[0063] Example 3

[0064] The same as example 1, except that a bolt is used as the substrate, the bolt is made of stainless steel, the length is 5 cm, the target-to-substrate distance in the ultra-low oxygen pressure sputtering and the low oxygen pressure sputtering is 5.1 cm, and the adjusted radial distance is 0.

[0065] Comparative Example 1

[0066] Compared with example 1, the difference is that a conventional lithium niobate target is used instead of a high-density LiNbO3 target to prepare a piezoelectric coating on the surface of a stainless steel sheet substrate.

[0067] The conventional lithium niobate target is made by uniformly mixing LiNbO3, LiNb3O8, and Li2O powders and pressing, and the ratio of LiNbO3: LiNb3O8: Li2O is 1:1:1. The density of the lithium niobate target is 4.40 g / cm 3 .

[0068] Test Example

[0069] XRD is used to test the piezoelectric coatings prepared in example 1 and comparative example 1. As can be seen from Figure 1 , when the radial distance is 0 and 4 cm, only the LiNbO3 piezoelectric phase exists in the piezoelectric coating prepared in example 1. As can be seen from Figure 2 , under the same conditions, the piezoelectric coating prepared in comparative example 1 simultaneously exists in LiNbO3, LiNb3O8, NbO, and Nb2O5 phases, and is not a pure LiNbO3 piezoelectric phase.

[0070] The piezoelectric constant and ultrasonic signal of the piezoelectric coatings prepared in example 1 and comparative example 1 are tested. As can be seen from Figure 3 and Figure 4 , in the same direction, the piezoelectric constant and ultrasonic signal of the piezoelectric coating decrease as the absolute value of the radial distance increases, and have the maximum value when the radial distance is 0, i.e., the center of the substrate coincides with the center of the target. In addition, the piezoelectric constant and ultrasonic signal of the piezoelectric coating prepared in example 1 are the highest, which are 14.3 pC / N and 2.53 V, respectively, and the piezoelectric constant and ultrasonic signal of the piezoelectric coating prepared in comparative example 1 are the highest, which are 2.9 pC / N and 0.24 V, respectively, i.e., under the same conditions, the high-density LiNbO3 target makes the piezoelectric constant and ultrasonic signal increase by 4.93 times and 10.54 times, respectively.

[0071] The piezoelectric coating prepared in Example 2 was tested using XRD, from which it can be seen that the crystal form of the prepared piezoelectric coating is basically the same as that of Example 1. Figure 5

[0072] The piezoelectric coating prepared in Example 2 at a radial distance of 0 was transferred to 700°C for annealing to study its high-temperature stability, from which it can be seen that at 700°C, the piezoelectric constant and the ultrasonic signal gradually increased with the extension of the annealing time, and reached the highest value at 160h, and there was no obvious decrease at a test time of 300h, which indicates that the piezoelectric coating has high high-temperature stability. Figure 6

[0073] The bolt with the piezoelectric coating prepared in Example 3 was transferred to 700°C for annealing, and the ultrasonic signal and the piezoelectric constant at different annealing times were tested. From Figures 7-9 it can be seen that the piezoelectric coating prepared on the bolt has high-temperature stability at 700°C, and the piezoelectric constant is still stable at 7.7pC / N after annealing for 100h.

[0074] Comparative Example 2

[0075] Compared with Example 1, the difference lies in that no sintering aid is used in the preparation process of the target, and the prepared lithium niobate target has a density of 4.50g / cm 3 .

[0076] The piezoelectric constant and the ultrasonic signal of the piezoelectric coating prepared in Comparative Example 2 were tested, and the highest (i.e. at the sputtering center) piezoelectric constant and ultrasonic signal were 4.3pC / N and 0.55V respectively, which were much lower than 14.3pC / N and 2.53V of Example 1, and the piezoelectric coating prepared in Comparative Example 2 simultaneously existed LiNbO3, LiNb3O8, NbO and Nb2O5 phases, and was not a pure LiNbO3 piezoelectric phase.

[0077] Comparative Example 3

[0078] Compared with Example 1, the difference lies in that the molar ratio of Nb2O5 to sintering aid Li2O is 10:1.6 in the preparation process of the target. Due to too much sintering aid, the number of holes in the target increases, and the prepared lithium niobate target has a density of 4.58g / cm 3 .

[0079] The piezoelectric constant and the ultrasonic signal of the piezoelectric coating prepared in Comparative Example 3 were tested, and the highest (i.e. at the sputtering center) piezoelectric constant and ultrasonic signal were 4.7pC / N and 0.61V respectively, which were much lower than 14.3pC / N and 2.53V of Example 1, and the piezoelectric coating prepared in Comparative Example 3 simultaneously existed LiNbO3, LiNb3O8, NbO and Nb2O5 phases, and was not a pure LiNbO3 piezoelectric phase. ​​

[0080] Comparative Example 4

[0081] Compared with Example 1, the difference is that in the target preparation process, instead of pressing a 2mm thick pre-billet each time, a 4mm thick billet is directly pressed. The prepared lithium niobate target has a density of 4.60g / cm 3 .

[0082] The piezoelectric constant and ultrasonic signal of the piezoelectric coating prepared in Comparative Example 4 are tested, and the piezoelectric constant and ultrasonic signal are respectively 6.9pC / N and 0.92V at the highest (i.e. at the sputtering center), which are much lower than 14.3pC / N and 2.53V of Example 1. At the same time, the piezoelectric coating prepared in Comparative Example 4 contains LiNbO3, LiNb3O8, NbO and Nb2O5 phases, and is not a pure LiNbO3 piezoelectric phase.

[0083] Comparative Example 5

[0084] Compared with Example 1, the difference is that in the target preparation process, the pressing pressure in the target forming step is reduced to 190MPa. The prepared lithium niobate target has a density of 4.45g / cm 3 .

[0085] The piezoelectric constant and ultrasonic signal of the piezoelectric coating prepared in Comparative Example 5 are tested, and the piezoelectric constant and ultrasonic signal are respectively 3.6pC / N and 0.34V at the highest (i.e. at the sputtering center), which are much lower than 14.3pC / N and 2.53V of Example 1. At the same time, the piezoelectric coating prepared in Comparative Example 5 contains LiNbO3, LiNb3O8, NbO and Nb2O5 phases, and is not a pure LiNbO3 piezoelectric phase.

[0086] Comparative Example 6

[0087] Compared with Example 1, the difference is that in the target preparation process, the pressing time in the target forming step is shortened to 4.5h. The prepared lithium niobate target has a density of 4.47g / cm 3 .

[0088] The piezoelectric constant and ultrasonic signal of the piezoelectric coating prepared in Comparative Example 6 are tested, and the piezoelectric constant and ultrasonic signal are respectively 3.8pC / N and 0.37V at the highest (i.e. at the sputtering center), which are much lower than 14.3pC / N and 2.53V of Example 1. At the same time, the piezoelectric coating prepared in Comparative Example 6 contains LiNbO3, LiNb3O8, NbO and Nb2O5 phases, and is not a pure LiNbO3 piezoelectric phase.

[0089] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a high-density LiNbO3 target material, characterized by, The application relates to a high-density LiNbO3 target material and a preparation method thereof. Li2CO3, Nb2O5 and Li2O are mixed and then pressed to form a blank; The blank is heat-treated to obtain the high-density LiNbO3 target material; The molar ratio of Li2CO3 and Nb2O5 is 1:1, and the molar ratio of Nb2O5 and Li2O is 8-10:0.5-1.5; The pressing is performed by isostatic pressing on a plurality of 2mm pre-blanks, and the plurality of pre-blanks are combined and pressed to form the blank, and the pressing is performed at a pressure of 200-500MPa for 5-10h; The heat treatment is performed in multiple stages, and the heat treatment is performed at 1000-1300 DEG C, 600-800 DEG C and 300-500 DEG C for 1-2h, 2-4h and 10-14h respectively.

2. The method for preparing the high-density LiNbO3 target material according to claim 1, characterized in that, The Li2CO3, Nb2O5 and Li2O are respectively subjected to water removal and preheating treatment before being mixed; The purity of the Li2CO3, Nb2O5 and Li2O is higher than 99.99%, and the particle size is lower than 800nm.

3. The method for preparing the high-density LiNbO3 target material according to claim 2, characterized in that, The preheating treatment is performed in multiple stages at 300-900 DEG C, wherein the temperature and time of the next stage are higher than those of the previous stage.

4. The method of claim 1, wherein the high-density LiNbO3 target is prepared by the steps of: preparing a LiNbO3 powder by a solid-state reaction method; mixing the LiNbO3 powder with a binder; and molding the mixture into a target shape. Before pressing, the Li2CO3, Nb2O5 and Li2O are mixed by wet ball milling, and then dried and passed through a 300-500 mesh screen to obtain fine powder, and the fine powder is subjected to heat treatment at 100-500 DEG C, wherein the heat treatment is performed in multiple stages, and the temperature of the next stage is lower than that of the previous stage, but the time of the next stage is longer than that of the previous stage.

5. A high-density LiNbO3 target material, characterized by, The high-density LiNbO3 target material is prepared by the preparation method.

6. A method of producing a LiNbO3 piezoelectric coating, characterized by, The high-density LiNbO3 target material is prepared by the preparation method. The magnetic control sputtering method comprises target pre-sputtering, ultra-low oxygen pressure sputtering and low oxygen pressure sputtering.

7. The method of claim 6, wherein the LiNbO3 piezoelectric coating is prepared by a method comprising: The parameters of the target pre-sputtering are as follows: RF power 800-1200W, total gas pressure of Ar and O2 0.5-1.5Pa, Ar / O2 gas flow ratio 2.5-6.2 / 1, temperature 150-250 DEG C, and time 5-15min; The parameters of the ultra-low oxygen pressure sputtering are as follows: RF power 800-1200W, total gas pressure of Ar and O2 0.5-1.5Pa, Ar / O2 gas flow ratio 4.2 / 1-8.2 / 1, substrate temperature 320-390 DEG C, target base distance 4.2-5.5cm, and film plating time 3-6h; The parameters of the low oxygen pressure sputtering are as follows: RF power 800-1200W, total gas pressure of Ar and O2 0.5-1.5Pa, Ar / O2 gas flow ratio 3.5 / 1-4.2 / 1, substrate temperature 320-390 DEG C, target base distance 4.2-5.5cm, and film plating time 3-6h.

8. A LiNbO3 piezoelectric coating, characterized by, The high-density LiNbO3 target material is prepared by the preparation method.

9. Application of the LiNbO3 piezoelectric coating in the sensing field.

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