TWI660989B - Pressure sensing film for underwater and down-hole and its manufacturing method - Google Patents

Abstract

The invention relates to an underwater downhole pressure sensing film and a preparation method thereof. The preparation method comprises: adding iron nitrate and bismuth nitrate in a molar ratio of 1: 1 to 1: 5 to an acidic solution, stirring for 6 to 10 hours; adding ethylene Acetone, stir for 10 ~ 14 hours, and let stand for 24 hours to obtain bismuth ferrite ethylene acetone solution; take an appropriate amount of bismuth ferrite ethylene acetone solution and drop it on a polyimide substrate, and perform at least one spin coating step and The first annealing step is to form a bismuth ferrite thin film; the second annealing step is performed to obtain the underwater downhole pressure sensing film of the present invention. The underwater downhole pressure sensing film of the present invention can be bent and is not easy to be broken. It is a single element and has no parts damage problem, and can be applied to sense underwater or downhole pressure.

Description

Underwater downhole pressure sensing film and preparation method thereof

The invention relates to an underwater downhole pressure sensing film and a preparation method thereof, in particular to a pressure sensing film coated on a lead-free flexible substrate.

Haptic sensor refers to the measurement of signals generated when two objects come into contact, such as the magnitude of stress, slippage, heat conduction, and hardness during contact, and converts these signals into measurable electrical or optical signals; The methods for measuring the stress include piezoresistive sensing technology, piezo-inductive sensing technology, capacitance sensing technology and optical sensing technology. Piezoelectric inductive measurement technology uses piezoelectric materials or piezoelectric films to deform when subjected to external forces, which will generate voltage characteristics and convert mechanical signals into voltage signals. If a current or an electric field is given to the piezoelectric material, the piezoelectric material will also be deformed. . Because the film is usually thin and light, it can be used as a sensor to detect subtle signals. It has the advantages of high sensitivity, low electromagnetic interference, low power dissipation, and so on.

At present, the piezoelectric material with better efficacy is a composite material made of lead titanate (PbTiO ₃ ) and lead zirconate (PbZrO ₃ ). The deformation degree can reach 20% when energized, but because lead is toxic and the process is It is quite troublesome, so we continue to develop lead-free piezoelectric materials. For example, the non-toxic bismuth ferrite single piezoelectric material developed in recent years can also achieve 20% deformation after being energized. Therefore, bismuth ferrite is considered as a new star in piezoelectric materials. However, during the preparation of bismuth ferrite materials, the bismuth element is easy to volatilize, and part of the iron ions (Fe ³⁺ ) will be transformed into ferrous ions (Fe ²⁺ ), so the material will generate more oxygen vacancies and affect the subsequent Applications.

Nowadays, the inventors consider that the existing underwater downhole pressure-sensing films are still missing in practical implementation, so they are a tireless spirit, supplemented by their rich professional knowledge and years of practical experience to improve them. Based on this, the invention was developed.

The invention relates to an underwater downhole pressure sensing film and a preparation method thereof, which mainly refers to coating a polyimide substrate with a bismuth ferrite solution to obtain a non-toxic and flexible piezoelectric film.

The invention provides an underwater downhole pressure sensing film and a preparation method thereof. The preparation method includes the following steps: Step 1: ferric nitrate [Fe (NO ₃ ) ₃ ‧9H ₂ O] with a molar ratio of 1: 1 to 1: 5. Add bismuth nitrate [Bi (NO ₃ ) ₃ ‧5H ₂ O] to an acidic solution and continue stirring for 6 to 10 hours. Step 2. Add ethylene acetone (pentane-2,4-dione) and continue stirring for 10 to 14 After 24 hours, let it stand for 24 hours to obtain a bismuth ferrite ethylene acetone solution. Step three, take 0.01 to 0.1 mL of a bismuth ferrite ethylene acetone solution and drop it on a polyimide substrate, and rotate it at a speed of 400 to 600 rpm. Coating for 10 to 30 seconds, and then spin coating at a rotation speed of 2800-3200 rpm for 20 to 40 seconds; step four, softly baking the polyimide substrate coated with bismuth ferrite ethylene acetone solution at 200 to 300 ° C 2- 5 minutes, and then perform a first annealing step at 300 to 400 ° C for 10 minutes to form a bismuth ferrite thin film; and step five, a second annealing step at 350 to 550 ° C for 15 to 25 minutes to obtain the underwater well Pressure sensing film. The underwater downhole pressure sensing film prepared by the specific method in this case can be used to prepare but is not limited to an underwater pressure sensor, an atmospheric pressure sensor, a robotic tactile sensor, a medical sensor or a piezoelectric generator.

In one embodiment of the present invention, the molar ratio of iron nitrate [Fe (NO ₃ ) ₃ ‧9H ₂ O] to bismuth nitrate [Bi (NO ₃ ) ₃ ‧5H ₂ O] is 1: 1.1.

In one embodiment of the present invention, the acidic solution is an acetic acid ethylene glycol mixed solution.

In one embodiment of the present invention, the mixed solution of ethylene glycol acetate is 10-20% by weight of acetic acid, 10-20% by weight of ethylene glycol and the remaining weight percent of pure water.

In one embodiment of the present invention, the ethylene glycol mixed solution is 13-15 wt% acetic acid, 14-17 wt% ethylene glycol and the remaining weight percent of pure water.

In one embodiment of the present invention, steps 3 to 4 are performed at least once.

In one embodiment of the invention, the underwater downhole pressure sensing film is coated with 2 to 6 layers of bismuth ferrite film.

In one embodiment of the present invention, the underwater downhole pressure sensing film is coated with two bismuth ferrite films.

Thereby, the underwater downhole pressure sensing film of the present invention can be coated with different layers of bismuth ferrite films according to requirements to obtain the required underwater downhole pressure sensing film.

FIG. 1 is a flowchart of preparing an underwater downhole pressure sensing film according to the present invention.

FIG. 2 is a scanning electron microscope analysis diagram of the underwater downhole pressure sensing film of the present invention.

Third figure: X-ray diffraction analysis diagram of the underwater downhole pressure sensing film of the present invention.

FIG. 4 is an analysis chart (1) of the output voltage of the underwater downhole pressure sensing film of the present invention.

Fifth figure: An analysis diagram of the output voltage of the underwater downhole pressure sensing film of the present invention (II).

Figure 6: An analysis diagram of the output voltage of the underwater downhole pressure sensing film of the present invention (3).

FIG. 7 is an analysis chart of the output voltage of the underwater downhole pressure sensing film of the present invention (4).

The purpose of the present invention and its structural and functional advantages will be explained based on the structure shown in the following drawings, in conjunction with specific embodiments, so that the reviewing committee can have a deeper and more specific understanding of the present invention.

The invention relates to an underwater downhole pressure sensing film, and a manufacturing method and application thereof, wherein the underwater downhole pressure sensing film comprises a polyimide substrate and at least one layer of a bismuth ferrite film; a preparation method includes the following steps: Add iron nitrate [Fe (NO ₃ ) ₃ ‧9H ₂ O] and bismuth nitrate [Bi (NO ₃ ) 3‧5H ₂ O] with a molar ratio of 1: 1 ~ 1: 5, and continue stirring for 6 ~ For 10 hours, the molar ratio of ferric nitrate and bismuth nitrate is 1: 1.1, and the acidic solution is a mixed solution of ethylene glycol, and the mixed solution contains 10 to 20% by weight of acetic acid and 10 to 20% by weight of ethylene glycol. Alcohol and pure water in the remaining weight percentage, wherein the content of acetic acid and ethylene glycol is preferably 13-15% by weight of acetic acid and 14-17% by weight of ethylene glycol; step two, adding ethylene acetone (pentane-2,4-dione) After stirring continuously for another 10 ~ 14 hours, let it stand for 24 hours to obtain a solution of bismuth ferrite ethylene acetone. Step three, take 0.01 ~ 0.1mL of bismuth ferrite ethylene acetone solution and drop it on a polyimide substrate. , Spin coating at a speed of 400 to 600 rpm for 10 to 30 seconds, and then spin coating at a speed of 2800 to 3200 rpm for 20 to 40 seconds; step four, apply the coating The polyimide substrate of the bismuth ferrite ethylene acetone solution is soft-baked at 200 to 300 ° C for 2-5 minutes, and then the first annealing step is performed at 300 to 400 ° C for 10 minutes to form a bismuth ferrite thin film; and step five, The second annealing step is performed at 350 to 550 ° C for 15 to 25 minutes to obtain the underwater downhole pressure sensing film of the present invention; wherein steps 3 and 4 are performed at least once.

The prepared underwater downhole pressure sensing film can be used to prepare a tactile sensor. The tactile sensor can be, but is not limited to, an underwater pressure sensor, an atmospheric pressure sensor, a robotic tactile sensor, and a medical sensor. Tester or piezoelectric generator.

In addition, through the following specific examples, the scope of the present invention can be further proved, but it is not intended to limit the scope of the present invention in any form.

Experiment 1. Preparation method of bismuth ferrite piezoelectric thin film

Please refer to the first figure. The method for preparing the underwater downhole pressure sensing film of the present invention is a melt-gel method. The preparation steps are as follows: Step 1: 0.15 to 0.3 mol of iron nitrate [Fe (NO ₃ ) ₃ ‧9H ₂ O] and 0.165-0.33mol of bismuth nitrate [Bi (NO ₃ ) ₃ ‧5H ₂ O] were added to 20-40mL of a mixed solution of acetic acid and ethylene glycol in proportion, This ethylene glycol mixed solution contains 10-20 mL of acetic acid and 10-20 mL of ethylene glycol.

Step 2: Add 20-40 mL of a 99% ethylene acetone (pentane-2,4-dione) solution to the mixed solution in step 1, and then continue stirring for 10 to 14 hours, then leave it for 24 hours to obtain one mole The concentration is 0.15 ~ 0.3mol% bismuth ferrite ethylene acetone solution.

Step 3: Take 0.01 ~ 0.1mL of bismuth ferrate ethylene acetone solution, drop it on a polyimide substrate, spin-coat at 450 rpm for 10 seconds, and spin-coat at 3000 rpm for 30 seconds; Step 4 : Baking the polyimide substrate coated with the bismuth ferrite ethylene acetone solution at 250 ° C for 3 minutes, and then performing a first annealing step at 350 ° C for 10 minutes to form a bismuth ferrite film; and step 5: A second annealing step is performed at 350 ~ 550 ° C for 15-25 minutes to obtain the underwater downhole pressure sensing film, which contains 0.15 ~ 0.3mol% bismuth ferrite.

In the above preparation step, if step 3 and step 4 are performed only once after step 2, an underwater downhole pressure sensing film with a single layer of bismuth ferrite film is prepared; if step 2 is repeated 2 or more times Steps 3 and 4 and the second annealing step of step 5 are performed to prepare an underwater downhole pressure sensing film with two or more bismuth ferrite films.

Experiment two: determination of properties of underwater downhole pressure sensing film

(I) Scanning electron microscope observation

This test uses scanning electron microscope observation to learn the surface structure of the underwater downhole pressure sensing film in this case; see the second picture, which is a bismuth ferrite film coated with 3 layers and containing 0.3mol% bismuth ferrite. Scanning electron microscope photograph of the underwater downhole pressure-sensing film obtained by performing the second annealing step at 350 ° C, 400 ° C, 450 ° C, and 500 ° C. When the second annealing step temperature is 350 ° C-450 ° C, the bismuth ferrite film The surface of the bismuth ferrite particle showed less crystals, and when the temperature of the second annealing step was 500 ° C, the surface of the bismuth ferrite thin film showed more bismuth ferrite particles and was uniformly dispersed.

(2) X-ray diffraction analysis

In this experiment, the crystal phase analysis of the bismuth ferrite thin film of the present invention is performed by X-ray diffraction analysis method, to coat three layers of bismuth ferrite thin film containing 0.3 mol% bismuth ferrite, and the temperature is 350 ° C, 400 ° C, and 450 ° C. The underwater downhole pressure-sensing film obtained by performing the second annealing step at 500 ° C was used as an experimental object for analysis. See the third figure. The test results show that the two diffraction peaks with strong crystalline strength correspond to (101) ) And (021), where (101) is the main crystalline phase of bismuth ferrite, which indicates that a lattice of bismuth ferrite does exist on the surface of the substrate, and (021) is bismuth ferrite produced by the melt-gel method ( Bi ₂ Fe ₄ O ₉ ) crystal structure; among them, the underwater downhole pressure sensing film prepared by using 450 ° C and 500 ° C for the second annealing step, the crystal planes (101) and (021) have higher strength Indicates that the underwater downhole pressure sensing film prepared at the two annealing temperatures has a better growth of the bismuth ferrite (101) crystal plane on the substrate.

(Two) piezoelectric feedback test

The prepared underwater downhole pressure-sensing film was connected to a wire using conductive silver glue, and the oscilloscope was used to detect the output voltage of different underwater downhole pressure-sensing films.

Please refer to the fourth figure, which analyzes the output voltage of the underwater downhole pressure sensing film prepared under the second annealing step at different temperatures. This experiment uses three layers of bismuth ferrite film containing 0.3mol% bismuth ferrite. When the second annealing step is performed at 350 ° C, 400 ° C, 450 ° C, and 500 ° C, the output voltage of the prepared underwater downhole pressure sensing film is as shown in the figure, under the application of 1.5 Newton (N) pressure, the first The output voltage of the second pressure sensing film produced at 350 ° C and 500 ° C is greater than or equal to 30mV; and the output voltage of the underwater downhole pressure sensing film at the second annealing temperature is 400 ° C and 450 ° C Small, about 24mV and 26mV, respectively.

Please refer to the fifth figure again. The second annealing temperature is 500 ° C, and 2 to 6 layers of underwater downhole pressure sensing films containing 0.15mol% bismuth ferrite or 0.3mol% bismuth ferrite are coated. Analysis chart of output voltage after Newton (N) pressure application; those containing 0.15mol% bismuth ferrite, in addition to the lower output voltage in the group with 5 coating layers, the pressure sensing film in other groups With more coating layers, the output voltage tends to increase accordingly; those containing 0.3mol% bismuth ferrite will have the highest output voltage when the number of coating layers is 3, and can reach up to Above 40mV, it is also higher than the output voltage of a pressure sensing film containing 0.15mol% bismuth ferrite.

Please refer to FIG. 6 again, perform the second annealing step at 500 ° C., and apply two layers of underwater downhole pressure sensing film made of 0.15mol% bismuth ferrite. The applied pressure is between 1 and 2 Newtons ( Within the range of N), the output voltage of the pressure sensing film will increase as the applied pressure rises.

Please refer to the seventh figure, and make the pressure sensing film of the present invention vibrate with a fixed frequency of 6.2kHz and detect the change of its output voltage. As shown in the seventh figure, except that the output voltage is In addition, the output voltage of the underwater downhole pressure sensing film does not change significantly. Its average output voltage is 984.68mV, which means that applying a pressure at a fixed frequency will not significantly affect the voltage of the underwater downhole pressure sensing film of the present invention. Output situation.

As can be seen from the foregoing implementation description, compared with the prior art, the present invention has the following advantages:

1. The underwater downhole pressure sensing film of the present invention is prepared by a sol-gel method, and the prepared film is uniformly distributed with bismuth ferrite crystals, and the crystallinity of the bismuth ferrite is high.

2. The underwater downhole pressure sensing film of the present invention is made of a lead-free material, which improves the lack of toxicity of conventional lead-containing materials.

3. In the underwater downhole pressure sensing film of the present invention, the polyimide substrate used has flexibility, which improves the defect that the ceramic substrate used in the past is easily broken.

In summary, the underwater downhole pressure sensing film of the present invention and the preparation method thereof can indeed achieve the expected use effect through the above-disclosed embodiments, and the present invention has not been disclosed before the application, and it is completely complete. Meet the requirements and requirements of the Patent Law. I filed an application for an invention patent in accordance with the law, and I urge you to examine it and grant the patent.

However, the description disclosed above is only a preferred embodiment of the present invention, and is not intended to limit the scope of protection of the present invention; it; anyone who is familiar with the technology, the scope of features according to the present invention, etc. Effect changes or modifications should be regarded as not departing from the design scope of the present invention.

Claims (9)

A method for manufacturing an underwater downhole pressure sensing film includes the following steps: Step 1: ferric nitrate [Fe (NO ₃ ) ₃ ‧9H ₂ O] with a molar ratio of 1: 1 to 1: 5 and bismuth nitrate [Bi (NO (NO ₃ ) ₃ ‧ 5H ₂ O] is added to a mixed solution of acetic acid ethylene glycol, and continuously stirred for 6 to 10 hours; Step 2: Add ethylene acetone (pentane-2,4-dione), and then After continuously stirring for 10 ~ 14 hours, let it stand for 24 hours to obtain a bismuth ferrite ethylene acetone solution. Step 3: Take 0.01 ~ 0.1mL of the bismuth ferrite ethylene acetone solution onto a polyimide substrate. Spin coating at a rotation speed of 400 to 600 rpm for 10 to 30 seconds, and then spin coating at a rotation speed of 2800 to 3200 rpm for 20 to 40 seconds. Step 4: The polyimide substrate coated with the bismuth ferrite ethylene acetone solution is 200 to Soft roast at 300 ° C for 2 ~ 5 minutes, and then perform the first annealing step at 300 ~ 500 ° C for 10 minutes to form a bismuth ferrite thin film; and Step 5: perform the second annealing step at 450 ~ 550 ° C for 15 ~ 25 minutes, To obtain the underwater downhole pressure sensing film. The manufacturing method described in item 1 of the scope of patent application, wherein the molar ratio of the iron nitrate [Fe (NO ₃ ) ₃ ‧9H ₂ O] and bismuth nitrate [Bi (NO ₃ ) ₃ ‧5H ₂ O] is 1 : 1.1. The manufacturing method according to item 1 of the scope of patent application, wherein steps 3 to 4 are performed at least once. The manufacturing method according to item 1 of the scope of the patent application, wherein the ethylene glycol mixed solution contains 10 to 20% by weight of acetic acid, 10 to 20% by weight of ethylene glycol, and the remaining weight percentage of pure water. An underwater downhole pressure sensing film, which comprises a polyimide substrate and is coated with at least one layer of bismuth ferrite thin film. The preparation method includes: Step 1: Morse ratio 1: 1 to 1: 5 Iron nitrate [Fe (NO ₃ ) ₃ ‧9H ₂ O] and bismuth nitrate [Bi (NO ₃ ) ₃ ‧5H ₂ O] were added to a mixed solution of acetic acid ethylene glycol and kept stirring 6 ~ 10 hours; Step 2: Add ethylene acetone (pentane-2,4-dione), continue stirring for 10 ~ 14 hours, and then stand for 24 hours to obtain bismuth ferrite ethylene acetone solution; Step 3: Take 0.1 ~ 1mL of the bismuth ferrite solution was dropped on a polyimide substrate, spin-coated at a speed of 400-600rpm for 10-30 seconds, and then spin-coated at a speed of 2800-3200rpm for 20-40 seconds; Step 4: The polyimide substrate coated with a bismuth ferrite ethylene acetone solution is soft-baked at 200 to 300 ° C for 2 to 5 minutes, and then subjected to a first annealing step at 300 to 500 ° C for 10 minutes to form a bismuth ferrite film; And step five: the second annealing step is performed at 450 to 550 ° C. for 15 to 25 minutes to obtain the underwater downhole pressure sensing film. The underwater downhole pressure sensing film described in item 5 of the scope of the patent application is coated with 2 to 6 layers of the bismuth ferrite film. For example, the underwater downhole pressure sensing film belonging to item 6 of the scope of patent application is coated with two layers of the bismuth ferrite film. A method for preparing a pressure sensor using the underwater downhole pressure sensing film described in item 5 of the scope of patent application, wherein the underwater downhole pressure sensing film comprises a polyimide substrate and is coated with At least one bismuth ferrite thin film. The application according to item 8 of the scope of patent application, wherein the underwater downhole pressure sensing film is coated with two layers of the bismuth ferrite film.