CN113465838A - Hydrogen sensor for leakage detection and preparation method of sensitive element thereof - Google Patents
Hydrogen sensor for leakage detection and preparation method of sensitive element thereof Download PDFInfo
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Abstract
The invention relates to a hydrogen sensor for leak detection and a preparation method of a sensitive element of the hydrogen sensor. The hydrogen sensor comprises a gas chamber, wherein one end of the gas chamber is provided with a gas inlet and a measuring probe, the other end of the gas chamber is provided with a gas outlet and a heating probe, a sensitive element is arranged in the gas chamber and comprises a substrate, a measuring electrode and a heating electrode, the measuring electrode and the heating electrode are arranged on the front surface and the back surface of the substrate, the measuring electrode is connected with the measuring probe, the heating electrode is connected with the heating probe, a shielding layer covers the heating electrode, and the measuring probe and the heating probe are respectively and electrically connected with a signal circuit positioned outside the gas chamber. The preparation method of the sensitive element comprises the following steps: plating the multi-walled carbon nanotube-loaded palladium-gold core-shell particle powder on the front surface of the substrate by adopting a vacuum coating method, and forming a measuring electrode after nano-photoetching; sputtering platinum powder on the back of the substrate in vacuum, and forming a heating electrode after nano-photoetching; and forming a silicon nitride film as a shielding layer covering the heating electrode by adopting a pulse laser deposition method. The invention has high hydrogen measuring sensitivity, reaching ppb level.
Description
Technical Field
The invention relates to a hydrogen sensor, in particular to a hydrogen sensor for leak detection and a preparation method of a sensitive element of the hydrogen sensor.
Background
In the process of automatic production, industrial leakage detection becomes a necessary practical technology for ensuring the tightness of devices and systems, and can be widely applied to the fields of aerospace, electronic industry, power industry grade refrigeration industry and the like.
Conventional industrial leak detection methods include differential pressure methods, water detection methods, ultrasonic methods, and trace gas methods. The differential pressure method has low detection rate, needs to be placed for a certain time, has the detection sensitivity equivalent to that of the water detection method, and can only detect 10-1Pa·m3And s. Detectable by ultrasonic method 10-2Pa·m3Minimum leak rate around/s. The tracer gas method is the method with highest sensitivity in the current industrial leak detection method, and can detect less than 10-5Pa·m3Leak rate in/s. The tracer gas used by the tracer gas method comprises radioactive gas, halogen gas, helium and hydrogen, wherein the helium leak detection method is the leak detection method with the highest sensitivity, but the helium leak detection cost is high, helium is a rare resource in China and is restricted by import for a long time, and a helium mass spectrometer leak detector needs to be matched with a vacuum system to realize, so that the application of a high-precision leak detection technology in industrial leak detection is limited.
The hydrogen leak detection method is a novel gas leak detection technology, the gas detection cost is more reasonable, but the hydrogen detection cannot reach the sensitivity same as that of helium at present, so that the hydrogen leak detection method cannot be developed in the application of micro-leakage and precision devices. Therefore, in order to use a low-cost hydrogen leak detection method instead of the helium leak detection method, which is relatively high in cost, it is necessary to develop a hydrogen sensor with high sensitivity up to ppb level.
Disclosure of Invention
In order to solve the technical problems, the invention provides a hydrogen sensor for leakage detection and a preparation method of a sensitive element thereof, and the sensitivity of the hydrogen sensor reaches ppb level and can be detected to be lower than 10-8Pa·m3The leakage rate per second is consistent with the detection sensitivity of the helium mass spectrometer leak detector, is suitable for industrial leak detection, and can be applied to detection of micro-leaks and precision devices.
The technical problem of the invention is mainly solved by the following technical scheme: the invention discloses a hydrogen sensor for leakage detection, which comprises a gas chamber, wherein the top of the gas chamber is provided with a gas inlet and two measuring probes, the bottom of the gas chamber is provided with a gas outlet and two heating probes, a sensitive element blocked between the gas inlet and the gas outlet is arranged in the gas chamber, the sensitive element comprises a substrate, a measuring electrode arranged on the front surface of the substrate and a heating electrode arranged on the back surface of the substrate, two ends of the measuring electrode are respectively connected with the two measuring probes, two ends of the heating electrode are respectively connected with the two heating probes, a shielding layer covers the heating electrode, and the measuring probe and the heating probes are respectively and electrically connected with a signal circuit positioned outside the gas chamber. When the gas chamber is in work, gas to be measured flows into the gas chamber from the gas inlet, flows through the substrate after being fully contacted with the measuring electrode on the front surface of the substrate, and then flows out of the gas chamber from the gas outlet. The signal circuit outputs fixed voltage to the heating electrode to enable the sensitive element to reach the required working temperature, meanwhile, the signal circuit collects signals of the measuring electrode through the measuring probe, after the measuring electrode is contacted with hydrogen in gas, the electrical performance of the measuring electrode can be changed, the signals output by the measuring electrode represent the concentration of the hydrogen in the gas, and the signals are processed by the signal circuit and then are transmitted to a main control module of a hydrogen analysis instrument, so that the leakage detection of equipment or components is completed.
Preferably, the substrate is a silicon oxide substrate, and the measuring electrode is a hydrogen-sensitive film formed by coating a film on multi-wall carbon nano tube loaded palladium-gold core-shell particle powder. The multi-walled carbon nanotube supported palladium-gold core-shell particle powder is a nano powder. When hydrogen exists in the gas to be detected, the gas to be detected enters the gas chamber to be fully contacted with the measuring electrode, after the measuring electrode adsorbs hydrogen, a palladium-hydrogen bonding bond is formed, so that the electron mobility of the measuring electrode is changed, and the resistance change of the measuring electrode reflects the amount of hydrogen adsorbed by the measuring electrode, so that the concentration of the hydrogen in the gas to be detected can be detected by detecting the resistance of the measuring electrode. The invention forms a highly sensitive hydrogen-sensitive film by vacuum coating the powder of the multi-walled carbon nano-tube loaded palladium-gold core-shell particles on the front surface of the substrate, the gold-core palladium-shell particles in the composite film have a crystal structure closest to palladium, so the hydrogen dissolving proportion is higher, the hydrogen sensitivity of the measuring electrode is effectively improved, the multi-walled carbon nano-tube forms a skeleton structure, the loaded gold-core palladium-shell particles are dispersed, the occurrence of the fracture phenomenon of a film microstructure caused by the expansion of the particles after hydrogen absorption is reduced, the electron mobility is increased, the hydrogen-sensitive response performance is improved, and the hydrogen detection sensitivity of a sensitive element is smaller than 5 ppb.
Preferably, the heating electrode is a platinum thin film formed by vacuum sputtering; the shielding layer is a silicon nitride film formed by pulsed laser deposition. The shielding layer is arranged to protect the heating electrode and prevent the resistance of the heating electrode from changing due to hydrogen embrittlement of the heating electrode caused by hydrogen.
Preferably, the measuring electrode comprises a plurality of straight line segments which are arranged in parallel at equal intervals, and arc line segments are connected between the heads and the tails of the adjacent straight line segments in a staggered manner, namely the measuring electrode is arranged in a serpentine bending manner; the shape of the heating electrode is the same as that of the measuring electrode. The length of the measuring electrode and the length of the heating electrode are prolonged as far as possible in a limited area, the contact area of the measuring electrode and gas is effectively increased, the hydrogen sensitivity of the measuring electrode is further improved, the heating efficiency of the heating electrode is improved, the sensitive element is ensured to reach the working temperature quickly, and the temperature distribution is uniform.
Preferably, the side wall of the air chamber is provided with two symmetrically arranged bosses, the edge of the substrate is provided with two symmetrically arranged grooves, the two grooves are respectively fixed on the two bosses, and a gap is formed between the edge of the substrate and the side wall of the air chamber. Not only ensures the stable installation of the substrate, but also ensures a gap between the substrate and the gas chamber to allow the gas to flow through.
Preferably, the signal circuit comprises a constant voltage output unit, and an impedance conversion unit, a filtering unit, a three-stage amplification unit, an analog-to-digital conversion unit and a serial interface which are connected in sequence, wherein the input end of the impedance conversion unit is connected with the measuring probe, and the output end of the constant voltage output unit is connected with the heating probe. The signal circuit outputs fixed voltage to the heating electrode through the constant voltage output unit, so that the temperature of the sensitive element reaches 300 ℃, meanwhile, the signal of the measuring electrode is acquired through the measuring probe, the signal output by the measuring electrode sequentially passes through the impedance conversion unit, the filtering unit, the three-stage amplification unit and the analog-to-digital conversion unit, a group of serial binary codes are demodulated and output to the serial interface, the serial interface is communicated with a main control module of a hydrogen analysis instrument, and the measured hydrogen concentration signal is output to the main control module.
The invention relates to a preparation method of a sensitive element of a hydrogen sensor for leak detection, which comprises the following steps: preparing the measuring electrode on the front surface of the substrate and preparing the heating electrode on the back surface of the substrate, wherein the preparation method of the measuring electrode comprises the following steps:
preparing a gold nucleus seed mixed solution;
preparing free palladium ion solution;
preparing gold-core palladium-shell colloidal solution;
preparing multi-walled carbon nanotube supported palladium-gold core-shell particle powder;
taking the multi-walled carbon nanotube supported palladium-gold nuclear shell particle powder as a sputtering target material, plating the multi-walled carbon nanotube supported palladium-gold nuclear shell particle powder on a substrate by adopting a vacuum coating method to form a hydrogen-sensitive film, and photoetching the hydrogen-sensitive film by adopting a nano photoetching technology to form a measuring electrode.
Preferably, the step (i) is: adding 5ml of chloroauric acid with the concentration of 0.05M into 50ml of hexadecyltrimethylammonium chloride solution with the concentration of 0.2M, quickly shaking for 3 minutes, adding into 10ml of sodium borohydride solution with the concentration of 0.05M, quickly shaking for 3 minutes again, standing for 2 hours at the constant temperature of 30 ℃ after the solution turns brown to obtain a gold nucleus seed mixed solution;
the second step is: weighing 3.54g of palladium chloride, dissolving the palladium chloride in 100ml of concentrated hydrochloric acid solution, isolating air, heating and stirring to form palladium chloride acid solution; diluting the chloropalladate solution to 0.01 mass percent, adding the solution into 50ml of 0.2M hexadecyl trimethyl ammonium chloride solution, and uniformly stirring to obtain a free palladium ion solution.
Preferably, the step (c) is: uniformly mixing the gold core seed mixed solution obtained in the step I and the free palladium ion solution obtained in the step II, slowly dripping 30ml of ascorbic acid into a burette, stirring for 30 minutes at the temperature of 0 ℃ in ice bath to obtain a gold core-palladium shell mixed solution, cleaning the gold core-palladium shell mixed solution with deionized water, centrifuging for multiple times on a centrifuge, and removing the supernatant of a centrifuge tube to obtain a lower gold core-palladium shell colloidal solution;
the fourth step is as follows: washing 0.5g of multi-walled carbon nanotube once with deionized water, filtering, adding 100ml of ethylene glycol, performing ultrasonic dispersion for 2h, adding 50ml of the gold-core palladium shell colloidal solution obtained in the third step, uniformly stirring, placing into a ball milling tank, grinding for 12 h with a ball mill, taking out the solution, performing centrifugal washing, removing supernatant of the centrifuge tube, placing the solution at the lower layer of the centrifuge tube into a vacuum drying box, drying for 6h at 120 ℃, and protecting with nitrogen in the drying process to obtain the powder of the multi-walled carbon nanotube-loaded palladium-gold-core shell particles.
Preferably, the preparation method of the heating electrode comprises the following steps: sputtering platinum powder on the back of the substrate in vacuum to form a platinum film, and photoetching the platinum film by adopting a nano photoetching technology to form a heating electrode; then adopting pulse laser deposition method to make alpha-Si3N4The monocrystalline silicon nitride is used as a target material and is deposited into a silicon nitride film, and a shielding layer is formed to cover the heating electrode.
The invention has the beneficial effects that: the method is characterized in that a high-sensitivity hydrogen-sensitive film is formed by carrying palladium-gold core-shell particle powder on a multiwalled carbon nanotube through vacuum coating and is used as a measuring electrode, the gold core-palladium shell particle in the hydrogen-sensitive film has a crystal structure closest to palladium, so that the hydrogen dissolving proportion is high, the hydrogen sensitivity of the measuring electrode is effectively improved, the multiwalled carbon nanotube forms a skeleton structure, and the gold core-palladium shell particle is dispersedly carried, so that the occurrence of film microstructure fracture phenomenon caused by particle expansion after hydrogen absorption is reduced, the electron mobility is increased, the hydrogen-sensitive response performance is improved, and the detection sensitivity of the hydrogen-sensitive film is smaller than 5 ppb. The invention prepares the measuring electrode and the heating electrode on the front and the back of the substrate respectively, and uses the silicon nitride film as the shielding layer covering the heating electrode to prepare the integrated hydrogen sensitive element, and adopts the integrated signal circuit to reduce the volume of the hydrogen sensor, thereby achieving the miniaturization, being applicable to the industrial leak detection, in particular to the leak detection of micro-leaks and precise devices.
Drawings
Fig. 1 is a schematic front view of a hydrogen sensor for leak detection according to the present invention.
Fig. 2 is a schematic front view of a sensor according to the present invention.
Fig. 3 is a schematic top view of the sensor of the present invention.
In the figure, 1, a shell, 2, a gas chamber, 3, a gas inlet pipe, 4, a gas inlet, 5, a gas outlet pipe, 6, a gas outlet, 7, a measuring probe, 8, a heating probe, 9, a signal circuit, 10, a sensitive element, 11, a substrate, 12, a measuring electrode, 13, a heating electrode, 14, a groove, 15, a boss, 16, a shielding layer and 17 are lead areas.
Detailed Description
The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings.
Example (b): the hydrogen sensor for leak detection in the embodiment, as shown in fig. 1, includes a cylindrical housing 1, which encloses a gas chamber 2, the diameter of the gas chamber is less than 20mm, and the height of the gas chamber is less than 10 mm. The shell is made of stainless steel materials, and has low adsorption rate and high temperature resistance. An air inlet pipe 3 communicated with the air chamber is arranged at the center of the top of the shell to form an air inlet 4, and two measuring probes 7 are also arranged at the top of the shell and are positioned at two sides of the air inlet pipe. An air outlet pipe 5 communicated with the air chamber is arranged in the center of the bottom of the shell to form an air outlet 6, and two heating probes 8 are also arranged at the bottom of the shell and are positioned at two sides of the air outlet pipe. The measuring probe and the heating probe are respectively connected with a signal circuit 9 positioned outside the shell through leads, the signal circuit comprises a constant voltage output unit, an impedance conversion unit, a filtering unit, a three-stage amplification unit, an analog-to-digital conversion unit and a serial interface, the measuring probe is connected with the input end of the impedance conversion unit, the impedance conversion unit is sequentially connected with the filtering unit, the three-stage amplification unit, the analog-to-digital conversion unit and the serial interface, and the output end of the constant voltage output unit is connected with the heating probe.
The middle part of the gas chamber is provided with a sensing element 10 which is parallel to the top part and the bottom part of the shell, the sensing element is blocked between the gas inlet and the gas outlet like a baffle, but a gap which can allow gas to flow through is arranged between the edge of the sensing element and the inner side wall of the shell. As shown in fig. 2, the sensing element includes a substrate 11, a measuring electrode 12, and a heating electrode 13. The substrate is a circular silicon oxide substrate, the diameter of the silicon oxide substrate is 2mm smaller than that of the air chamber, two symmetrically-arranged grooves 14 are formed in the edge of the substrate, two symmetrically-arranged bosses 15 are arranged on the side wall of the air chamber, the two grooves are respectively fixed on the two bosses, and a gap is formed between the edge of the substrate and the side wall of the air chamber. As shown in fig. 3, the front surface of the substrate 11 has a measuring electrode 12, the measuring electrode is opposite to the air inlet, the measuring electrode is a hydrogen sensitive film formed by coating a multi-walled carbon nanotube loaded with palladium-gold core-shell particle powder by a vacuum coating method, and then is photo-etched into a shape of serpentine and curved arrangement by using a nano-lithography technology, that is: the measuring electrode comprises a plurality of straight line segments which are arranged in parallel at equal intervals, the heads and the tails of the adjacent straight line segments are connected with 180-degree arc line segments in a staggered mode, and two ends of the measuring electrode are provided with 0.5mm multiplied by 0.5mm lead wire areas 17 which are respectively connected with lead wires connected with the measuring probe. In this example, the measuring electrode had a thickness of 30nm, a width of 0.2mm and a length of 65 mm. The back of the substrate 11 is provided with a heating electrode 13 which is opposite to the air outlet, the heating electrode is a platinum film formed by vacuum sputtering, and then the heating electrode is photoetched into a shape of snake-shaped bent arrangement by adopting a nano photoetching technology, namely: the heating electrode comprises a plurality of straight line segments which are arranged in parallel at equal intervals, and 180-degree circular arc line segments are connected between the heads and the tails of the adjacent straight line segments in a staggered manner. The shape of the heating electrode is the same as that of the measuring electrode, the position of the heating electrode corresponds to that of the measuring electrode, and two ends of the heating electrode are provided with lead areas of 0.5mm multiplied by 0.5mm which are respectively connected with the heating probes. In this example, the thickness of the heating electrode was 100nm, the width was 0.2mm, and the length was 65 mm. The heating electrode is covered with a shielding layer 16, the shielding layer is a compact silicon nitride film formed by pulse laser deposition, and the thickness of the silicon nitride film is 20 nm.
When the gas chamber works, gas to be measured flows into the gas chamber from the gas inlet, fully contacts with the front surface of the substrate, flows through a gap between the substrate and the side wall of the gas chamber, and finally flows out of the gas chamber from the gas outlet. The signal circuit outputs fixed voltage to the heating electrode through the constant voltage output unit, so that the sensitive element reaches the working temperature of 300 ℃. The gas to be measured flows into the gas chamber, the measuring electrode absorbs hydrogen in the gas to be measured to form a palladium-hydrogen bonding bond, so that the electron mobility of the measuring electrode changes, the change of the resistance reflects the concentration of the hydrogen in the gas to be measured, the signal circuit acquires the resistance of the measuring electrode through the measuring probe, the resistance sequentially passes through the impedance transformation unit, the filtering unit, the three-stage amplification unit and the analog-to-digital conversion unit, a group of serial binary codes are demodulated and output to the serial interface, the serial interface is communicated with a main control module of a hydrogen analysis instrument, and the measured hydrogen concentration signal is output to the main control module.
The preparation method of the sensitive element of the hydrogen sensor for leak detection in this embodiment is as follows: a measuring electrode is formed on the front surface of the substrate, and a heating electrode is formed on the back surface of the substrate.
The preparation method of the measuring electrode comprises the following steps:
preparing a gold nucleus seed mixed solution: adding 5ml of chloroauric acid with the concentration of 0.05M into 50ml of hexadecyltrimethylammonium chloride solution with the concentration of 0.2M, quickly shaking for 3 minutes, adding into 10ml of sodium borohydride solution with the concentration of 0.05M, quickly shaking for 3 minutes again, standing for 2 hours at the constant temperature of 30 ℃ after the solution turns brown to obtain a gold nucleus seed mixed solution;
preparing free palladium ion solution: weighing 3.54g of palladium chloride, dissolving the palladium chloride in 100ml of concentrated hydrochloric acid solution, isolating air, heating and stirring to form palladium chloride acid solution; diluting a chloropalladate solution to 0.01% (omega) concentration, adding the solution into 50ml of 0.2M hexadecyl trimethyl ammonium chloride solution, and uniformly stirring to obtain a free palladium ion solution;
preparing a gold-core palladium-shell colloidal solution: uniformly mixing the gold core seed mixed solution obtained in the step I and the free palladium ion solution obtained in the step II, slowly dripping 30ml of ascorbic acid into a burette, stirring for 30 minutes at the temperature of 0 ℃ in ice bath to obtain a gold core-palladium shell mixed solution, cleaning the gold core-palladium shell mixed solution with deionized water, centrifuging for multiple times on a centrifuge, and removing the supernatant of a centrifuge tube to obtain a lower gold core-palladium shell colloidal solution;
preparing multi-wall carbon nano tube loaded palladium-gold core-shell particle powder: washing 0.5g of multi-walled carbon nanotube once with deionized water, filtering, adding 100ml of ethylene glycol, performing ultrasonic dispersion for 2h, adding 50ml of gold-core palladium-shell colloidal solution obtained in the third step, uniformly stirring, putting into a polytetrafluoroethylene ball-milling tank, grinding for 12 h with a ball mill, taking out the solution, performing centrifugal washing, removing supernatant of the centrifugal tube, putting the solution at the lower layer of the centrifugal tube into a vacuum drying box, drying for 6h at 120 ℃, and protecting with nitrogen with the purity of 99.999% in the drying process to obtain the powder of the multi-walled carbon nanotube-loaded palladium-gold-core shell particles;
taking a round silicon oxide substrate as a substrate, carrying out ultrasonic cleaning for 15min by using distilled water and ethylene glycol in sequence, drying at 100 ℃, taking the multiwall carbon nanotube-loaded palladium-gold nuclear shell particle powder obtained in the step (iv) as a sputtering target material, plating the multiwall carbon nanotube-loaded palladium-gold nuclear shell particle powder on the substrate by adopting a vacuum coating method, wherein the vacuum degree is lower than 5 multiplied by 10-5Pa starts to plate, the temperature is 500 ℃, the sputtering power is 150W, and the sputtering rate is
And (3) performing heat treatment for 6h at 300 ℃ after the film plating to form a hydrogen-sensitive film with the thickness of 30nm, and photoetching the hydrogen-sensitive film by adopting a nano photoetching technology to form a serpentine measuring electrode.
The preparation method of the heating electrode comprises the following steps: the heating electrode is made of a pure platinum film, platinum powder is sputtered on the back of the substrate in a vacuum mode to form a platinum film with the thickness of 100nm, and photoetching is carried out on the platinum film by adopting a nano photoetching technology to form a serpentine heating electrode; then adopting pulse laser deposition method to obtain high-purity alpha-Si3N4Using single crystal silicon nitride as target material, depositing to form silicon nitride film with thickness of 20nm at substrate temperature of 200 deg.C, nitrogen pressure of 5Pa and pulse energy of 200mJ, and heat treating at 300 deg.C in nitrogen atmosphereAnd 1h, forming a shielding layer covering the heating electrode.
Claims (10)
1. The utility model provides a hydrogen sensor for leak detection, its characterized in that includes an air chamber, the top of air chamber is equipped with an air inlet and two measuring probe, the bottom of air chamber is equipped with an air outlet and two heating probe, be equipped with a sensing element that keeps off between air inlet and air outlet in the air chamber, sensing element includes the base plate and establishes the measuring electrode at the base plate front, establish the heating electrode at the base plate back, the both ends of measuring electrode link to each other with two measuring probe respectively, the both ends of heating electrode link to each other with two heating probe respectively, heating electrode coats and is stamped the shielding layer, measuring probe, heating probe still are connected with the signal circuit electricity that is located the air chamber respectively.
2. The hydrogen sensor for leak detection according to claim 1, wherein the substrate is a silicon oxide substrate, and the measuring electrode is a hydrogen-sensitive film formed by coating a multi-walled carbon nanotube-supported palladium-gold core-shell particle powder.
3. A hydrogen sensor for leak detection according to claim 1, wherein said heating electrode is a platinum thin film formed by vacuum sputtering; the shielding layer is a silicon nitride film formed by pulsed laser deposition.
4. The hydrogen sensor for leak detection according to claim 1, 2 or 3, wherein the measuring electrode comprises a plurality of equally spaced parallel straight segments, and arc segments are alternately connected between the heads and the tails of adjacent straight segments, i.e. the measuring electrode is arranged in a serpentine shape; the shape of the heating electrode is the same as that of the measuring electrode.
5. The hydrogen sensor for leak detection according to claim 1, 2 or 3, wherein the side wall of the gas chamber is provided with two symmetrically arranged bosses, the edge of the substrate is provided with two symmetrically arranged grooves, the two grooves are respectively fixed on the two bosses, and a gap is formed between the edge of the substrate and the side wall of the gas chamber.
6. The hydrogen sensor for leak detection according to claim 1, wherein the signal circuit comprises a constant voltage output unit, and an impedance transformation unit, a filter unit, a three-stage amplification unit, an analog-to-digital conversion unit and a serial interface connected in sequence, wherein an input terminal of the impedance transformation unit is connected to the measurement probe, and an output terminal of the constant voltage output unit is connected to the heating probe.
7. A method for producing a sensor element of a hydrogen sensor for leak detection according to claim 1, wherein said measuring electrode is produced on the front surface of said substrate, and said heating electrode is produced on the back surface of said substrate, and the method for producing a measuring electrode comprises the steps of:
preparing a gold nucleus seed mixed solution;
preparing free palladium ion solution;
preparing gold-core palladium-shell colloidal solution;
preparing multi-walled carbon nanotube supported palladium-gold core-shell particle powder;
taking the multi-walled carbon nanotube supported palladium-gold nuclear shell particle powder as a sputtering target material, plating the multi-walled carbon nanotube supported palladium-gold nuclear shell particle powder on a substrate by adopting a vacuum coating method to form a hydrogen-sensitive film, and photoetching the hydrogen-sensitive film by adopting a nano photoetching technology to form a measuring electrode.
8. The method for preparing a sensor element of a hydrogen sensor for leak detection according to claim 7, wherein the steps (i) are: adding 5ml of chloroauric acid with the concentration of 0.05M into 50ml of hexadecyltrimethylammonium chloride solution with the concentration of 0.2M, quickly shaking for 3 minutes, adding into 10ml of sodium borohydride solution with the concentration of 0.05M, quickly shaking for 3 minutes again, standing for 2 hours at the constant temperature of 30 ℃ after the solution turns brown to obtain a gold nucleus seed mixed solution;
the second step is: weighing 3.54g of palladium chloride, dissolving the palladium chloride in 100ml of concentrated hydrochloric acid solution, isolating air, heating and stirring to form palladium chloride acid solution; diluting the chloropalladate solution to 0.01 percent of concentration, adding the solution into 50ml of 0.2M hexadecyl trimethyl ammonium chloride solution, and uniformly stirring to obtain a free palladium ion solution.
9. The method for preparing a sensor of a hydrogen sensor for leak detection according to claim 7 or 8, wherein the third step is: uniformly mixing the gold core seed mixed solution obtained in the step I and the free palladium ion solution obtained in the step II, slowly dripping 30ml of ascorbic acid into a burette, stirring for 30 minutes at the temperature of 0 ℃ in ice bath to obtain a gold core-palladium shell mixed solution, cleaning the gold core-palladium shell mixed solution with deionized water, centrifuging for multiple times on a centrifuge, and removing the supernatant of a centrifuge tube to obtain a lower gold core-palladium shell colloidal solution;
the fourth step is as follows: washing 0.5g of multi-walled carbon nanotube once with deionized water, filtering, adding 100ml of ethylene glycol, performing ultrasonic dispersion for 2h, adding 50ml of the gold-core palladium shell colloidal solution obtained in the third step, uniformly stirring, placing into a ball milling tank, grinding for 12 h with a ball mill, taking out the solution, performing centrifugal washing, removing supernatant of the centrifuge tube, placing the solution at the lower layer of the centrifuge tube into a vacuum drying box, drying for 6h at 120 ℃, and protecting with nitrogen in the drying process to obtain the powder of the multi-walled carbon nanotube-loaded palladium-gold-core shell particles.
10. The method for preparing a sensing element of a hydrogen sensor for leak detection according to claim 7, wherein the method for preparing the heating electrode comprises: sputtering platinum powder on the back of the substrate in vacuum to form a platinum film, and photoetching the platinum film by adopting a nano photoetching technology to form a heating electrode; then adopting pulse laser deposition method to make alpha-Si3N4Depositing silicon nitride film as target material to form shielding layer covering the heating electrode.
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Cited By (2)
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|---|---|---|---|---|
| CN114544114A (en) * | 2022-01-06 | 2022-05-27 | 温州大学 | Helium vacuum leak rate detection method based on carbon nanotube field emission sensor |
| CN115308270A (en) * | 2022-08-05 | 2022-11-08 | 郑州炜盛电子科技有限公司 | Palladium alloy film hydrogen sensor and preparation method and use method thereof |
-
2021
- 2021-06-25 CN CN202110714196.0A patent/CN113465838A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114544114A (en) * | 2022-01-06 | 2022-05-27 | 温州大学 | Helium vacuum leak rate detection method based on carbon nanotube field emission sensor |
| CN115308270A (en) * | 2022-08-05 | 2022-11-08 | 郑州炜盛电子科技有限公司 | Palladium alloy film hydrogen sensor and preparation method and use method thereof |
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