Ultrasonic temperature sensor and temperature sensing rod

Abstract

The utility model provides an ultrasonic temperature sensor and a temperature sensing rod, and relates to the technical field of temperature sensors, the ultrasonic temperature sensor comprises an anti-corrosion layer, a crystallization induction layer, a piezoelectric function layer, a protection layer and an electrode layer which are arranged on the surface of a substrate in sequence from inside to outside, and the piezoelectric function layer is a ZnCoO coating. The ultrasonic sensor has the advantages that the ultrasonic sensor is made of sputtering type ZnCoO piezoelectric composite film materials, the protective layer is made of corrosion-resistant and high-temperature-resistant aluminum oxide, and the preparation process is easy to engineer.

Description

Technical Field

[0001] The utility model relates to the technical field of ultrasonic temperature sensors, in particular to an ultrasonic temperature sensor and a temperature sensing rod. Background Art

[0002] Temperature sensors are widely used in industry, agriculture, commerce and other sectors. Temperature sensors are the core part of temperature measuring instruments and come in a wide variety. According to the measurement method, they can be divided into two categories: contact and non-contact. The detection part of the contact temperature sensor has good contact with the object being measured, also known as a thermometer. Commonly used ones include bimetallic thermometers, glass liquid thermometers, pressure thermometers, resistance thermometers, thermistors and thermocouples. The thermometer reaches thermal equilibrium through conduction or convection, so that the indication of the thermometer can directly represent the temperature of the object being measured. The detection part has good contact with the object being measured and reaches thermal equilibrium through conduction or convection, so that the indication of the thermometer can directly represent the temperature of the object being measured. Within a certain temperature measurement range, the thermometer can also measure the temperature distribution inside the object. However, for moving objects, small targets or objects with very small heat capacity, large measurement errors will be generated, while contact temperature sensors generally have higher measurement accuracy. Non-contact temperature sensors can be used to measure the surface temperature of moving objects, small targets and objects with small heat capacity or rapid temperature changes, and can also be used to measure the temperature distribution of temperature fields. The advantage is that the upper limit of measurement is not limited by the temperature resistance of the temperature sensing element, so there is no limit on the maximum measurable temperature in principle.

[0003] Thermocouples are the most commonly used technology for contact temperature measurement. They consist of two metal wires of different materials, welded together at the ends. When one end of the thermocouple is heated, there is a potential difference in the thermocouple circuit. The temperature can be calculated using the measured potential difference. Since it must have two conductors of different materials, it is called a thermocouple. Thermocouples made of different materials are used in different temperature ranges, and their sensitivities are also different. The sensitivity of a thermocouple refers to the change in the output potential difference when the temperature of the heating point changes by 1°C. Since the sensitivity of a thermocouple temperature sensor has nothing to do with the thickness of the material, a temperature sensor can be made of very fine materials. Also, because the metal material used to make the thermocouple has good ductility, this fine temperature measuring element has an extremely high response speed and can measure rapidly changing processes. Thermocouples are the most commonly used temperature sensors in temperature measurement. Its main advantages are a wide temperature range and adaptability to various atmospheric environments, and it is also strong, low-priced, does not require power, and is the cheapest. Thermocouples are the simplest and most versatile temperature sensors, but thermocouples are not suitable for high-precision measurements and applications.

[0004] Thermistors are made of semiconductor materials, most of which have a negative temperature coefficient, that is, the resistance decreases as the temperature increases. Temperature changes will cause large changes in resistance, so it is the most sensitive temperature sensor. However, the linearity of thermistors is extremely poor and has a lot to do with the production process. Manufacturers cannot provide standardized thermistor curves. The small size of thermistors is an advantage, and they can stabilize quickly and will not cause heat load. However, they are also very fragile, and large currents will cause self-heating. Since thermistors are resistive devices, any current source will cause heat on them due to power. Therefore, a small current source should be used. If thermistors are exposed to high heat, they will cause permanent damage.

[0005] The most commonly used non-contact temperature measuring instruments are based on the basic law of blackbody radiation. Radiation temperature measurement methods include brightness method (see optical pyrometer), radiation method (see radiation pyrometer) and colorimetry (see colorimetric thermometer). Various radiation temperature measurement methods can only measure the corresponding photometric temperature, radiation temperature or colorimetric temperature. Only the temperature measured for the blackbody is the real temperature. If you want to determine the real temperature of an object, you must correct the surface emissivity of the material. The surface emissivity of the material depends not only on temperature and wavelength, but also on surface state, coating and microstructure, so it is difficult to measure accurately. In automated production, it is often necessary to use radiation temperature measurement to measure or control the surface temperature of certain objects, such as the rolling temperature of steel strips, roller temperature, forging temperature and the temperature of various molten metals in smelting furnaces or crucibles in metallurgy. In these specific cases, it is quite difficult to measure the surface emissivity of objects.

[0006] For example, the utility model patent with the announcement number CN217466018U discloses a thermocouple temperature sensor, including a probe part, a sealing shell is provided on the outer side of the probe part, a fastening seat is provided on the right end of the probe part, a telescopic protective shell is provided on the right side of the fastening seat; the telescopic protective shell has a bell mouth at the rear end of the telescopic protective shell, and a plurality of contact guides are provided inside the bell mouth. However, the technical solution provided by the utility model cannot prevent the corrosion of the thermocouple by corrosive substances, and the thermocouple sensor has a slow response speed and cannot adapt to the occasions where the temperature changes rapidly.

[0007] Due to the slow response speed of thermocouples, they are not suitable for occasions with rapid temperature changes. Non-contact methods such as thermal imagers cannot measure temperature changes in confined spaces, and they are expensive. Therefore, it is urgent to develop high-sensitivity temperature sensors that can work in high and low temperature environments to meet the needs of industrial temperature measurement. Utility Model Content

[0008] In order to overcome the problems in the prior art that thermocouples have high temperature measurement accuracy but slow response speed and cannot work in corrosive environments; infrared thermal imagers are convenient to measure but expensive and cannot measure the temperature in a closed environment, the utility model provides an ultrasonic temperature sensor and a temperature sensor rod. The specific technical solution is as follows:

[0009] An ultrasonic temperature sensor comprises an anti-corrosion layer, a crystal induction layer, a piezoelectric functional layer, a protective layer and an electrode layer which are sequentially arranged on the surface of the substrate from the inside to the outside, and the piezoelectric functional layer is a ZnCoO coating.

[0010] Preferably, the piezoelectric functional layer is a (002) oriented columnar crystal ZnCoO coating.

[0011] Preferably, the anti-corrosion layer is an aluminum oxide layer, and the thickness of the anti-corrosion layer is 10 to 100 μm.

[0012] Preferably, the crystallization inducing layer is a (002) oriented Co nanocrystalline layer, and the nanocrystalline size of the inducing layer is 10 to 100 nm and the thickness is 50 to 200 nm.

[0013] Preferably, the protective layer is an aluminum oxide layer, and the thickness of the protective layer is 10 to 100 μm.

[0014] Preferably, the electrode layer is a Co layer, and the thickness of the electrode layer is 5-10 μm.

[0015] A temperature sensing rod comprises a substrate and an ultrasonic temperature sensor mounted on an end surface of the substrate.

[0016] Preferably, the substrate is a cylinder made of deformed aluminum alloy or cast aluminum alloy, and the length of the substrate is 50 to 1000 mm and the diameter is 5 to 10 mm.

[0017] Preferably, an annular ultrasonic reflection defect is formed on the outer circumferential surface of the substrate at a distance of 5 to 100 mm from the end thereof away from the piezoelectric functional layer; the ultrasonic reflection defect has a depth of 1 to 2 mm and a width of 0.5 to 1 mm.

[0018] Preferably, the central axis of the annular ultrasonic reflection defect coincides with the central axis of the substrate.

[0019] Compared with the prior art, the beneficial effects of the utility model are:

[0020] 1. The utility model applies ultrasonic technology to temperature detection, avoiding the shortcomings of traditional thermocouples, such as slow response speed and inability to work in corrosive environments; ultrasonic technology has a fast response speed, which is at the nanosecond level, so it can respond to very small changes in temperature; and at the same time, by setting ultrasonic reflection defects on the sensor, the accuracy of temperature detection is improved, avoiding errors caused by uneven spatial distribution of temperature of ultrasonic conduction rods.

[0021] 2. The utility model uses a multilayer structure to form a low-stress ultrasonic sensor with materials such as aluminum oxide, ZnCoO, and Co, thereby improving the bonding strength between the ultrasonic sensor and the aluminum alloy; compared with the conventional single-layer ZnO piezoelectric coating material, the utility model uses Co-doped ZnO to form a ZnCoO piezoelectric film with a high piezoelectric constant, which allows the sensor to work in a high-temperature environment and meet the application requirements under different temperature conditions. At the same time, its industrial production batch is easy to achieve, the processing efficiency is high, and the production cost of the manufacturer can be greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the device structure of the utility model;

[0024] Figure 2 This is a schematic diagram of the sensor coating structure of the utility model;

[0025] Figure 3 This is a schematic diagram of the equipment structure used in preparing the sensor of the utility model;

[0026] Among them: 1-substrate, 2-ultrasonic reflection defect, 3-anti-corrosion layer, 4-crystallization induction layer, 5-piezoelectric functional layer, 6-protective layer, 7-electrode layer, 8-exhaust port, 9-Co target, 10-aluminum target, 11-ZnCoO target, 12-door, 13-ultrasonic temperature sensor. DETAILED DESCRIPTION

[0027] The following will be combined with specific embodiments to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the utility model.

[0028] Traditional ZnO materials have insufficient corrosion resistance and cannot withstand steam corrosion. Compared with conventional single-layer ZnO piezoelectric coating materials, the utility model uses Co-doped ZnO to form a ZnCoO piezoelectric film, which improves the piezoelectric performance while also improving its corrosion resistance. The specific technical solution is as follows:

[0029] like Figure 2 An ultrasonic temperature sensor is shown, the sensor comprising an anti-corrosion layer 3, a crystallization inducing layer 4, a piezoelectric functional layer 5, a protective layer 6 and an electrode layer 7 which are sequentially arranged on the surface of the substrate 1 from the inside to the outside, the piezoelectric functional layer 5 is a ZnCoO coating, and the utility model utilizes a multilayer structure to form a low-stress ultrasonic sensor with materials such as alumina, ZnCoO, and Co, thereby improving the bonding strength between the ultrasonic sensor and the aluminum alloy.

[0030] Specifically, the piezoelectric functional layer 5 is a columnar crystal ZnCoO coating with a (002) orientation. Compared with the conventional single-layer ZnO piezoelectric coating material, the utility model uses Co-doped ZnO to form a ZnCoO piezoelectric film to improve the piezoelectric performance. The traditional ZnO material has insufficient corrosion resistance and cannot withstand steam corrosion. After Co is added to the ZnO material, its corrosion resistance is improved.

[0031] Specifically, the anti-corrosion layer 3 is an aluminum oxide layer, and the thickness of the anti-corrosion layer 3 is 10-100 μm.

[0032] Specifically, the crystal induction layer 4 is a (002) oriented Co nanocrystalline layer, and the nanocrystalline size of the induction layer is 10-100 nm and the thickness is 50-200 nm.

[0033] Specifically, the protective layer 6 is an aluminum oxide layer, the thickness of the protective layer 6 is 10 to 100 μm, and it has the characteristics of wear resistance and corrosion resistance; traditional aluminum alloys have low hardness and poor wear resistance, and cannot meet the requirements of corrosion-resistant and wear-resistant environments, especially temperature sensors are often subject to wear and corrosion.

[0034] Specifically, the electrode layer 7 is a Co layer, and the thickness of the electrode layer 7 is 5-10 μm.

[0035] like Figure 1 As shown, a temperature sensing rod comprises a substrate 1 and an ultrasonic temperature sensor mounted on an end surface of the substrate 1 .

[0036] Specifically, the substrate 1 is a cylinder made of a deformed aluminum alloy or a cast aluminum alloy, and the length of the substrate 1 is 50 to 1000 mm and the diameter is 5 to 10 mm.

[0037] Specifically, an annular ultrasonic reflection defect 2 is formed on the outer circumferential surface of the substrate 1 at a distance of 5 to 100 mm from the end thereof away from the piezoelectric functional layer 5; the ultrasonic reflection defect 2 has a depth of 1 to 2 mm and a width of 0.5 to 1 mm, and fully utilizes the ultrasonic reflection characteristics of the groove to improve the temperature detection accuracy and avoid errors caused by uneven spatial distribution of temperature of the ultrasonic conduction rod.

[0038] Specifically, the central axis of the annular ultrasonic reflection defect 2 coincides with the central axis of the substrate 1 .

[0039] This embodiment further provides a temperature sensing rod, including a substrate and an ultrasonic temperature sensor installed on an end surface of the substrate.

[0040] like Figure 3 The device used in this embodiment is shown. The vacuum chamber of the device is surrounded by the furnace wall. The vacuum chamber is provided with an exhaust port 8. The vacuum pumping unit evacuates the vacuum chamber through the exhaust port 8. Three targets are installed on the furnace wall in three rows, one is an etching aluminum target 10, one is a coating Co target 9 and one is a ZnCoO target 11. The sample is mounted on the workpiece rack. This layout greatly increases the plasma density in the vacuum chamber, and the workpiece is completely immersed in the plasma. The deposition rate, hardness and adhesion of the coating are greatly improved. Due to the optimization of the target structure, the magnetic field distribution is more uniform, so that the magnetron sputtering target surface is evenly etched, and the uniformity of the coating is improved.

[0041] For a better understanding of the present invention, the following embodiments are further explanations of the present invention, but the content of the present invention is not limited to the following embodiments.

[0042] Embodiment 1:

[0043] The method for preparing the temperature sensing rod with the ultrasonic temperature sensor in this embodiment comprises the following steps:

[0044] Step 1: using a deformed aluminum alloy or a cast aluminum alloy with a length of 50 mm and a diameter of 5 mm as a substrate, processing a ring defect with a depth of 1 mm and a width of 0.5 mm on the surface of the substrate as an ultrasonic reflection defect, and the distance between the ultrasonic reflection defect and one end of the substrate is 5 mm;

[0045] Step 2: Place the substrate in a power supply with a positive voltage of 450 V, a negative voltage of 250 V, a positive and negative duty cycle of 10%, and a frequency of 500 Hz. 2 SiO 3 、Na 2 B 4 O 7 , NaOH and Na 3 AlO 3Pulse micro-arc oxidation is carried out in a silicate and aluminate mixed electrolyte to form an anti-corrosion layer, and the oxidation time is 10 minutes;

[0046] Step 3: after the pulse micro-arc oxidation is completed, a Co crystallization induction layer with a thickness of 50 nm and a nanocrystalline size of 10 nm (002) orientation is deposited on the surface of the anti-corrosion layer under an environment of a temperature of 100° C. and a pressure of 0.5 Pa;

[0047] Step 4: After the crystallization induction layer is deposited, a (002) oriented ZnCoO piezoelectric functional layer is deposited under the conditions of 0.5 Pa and 0 V, wherein the ZnCoO piezoelectric material is a Co-doped ZnO coating with a Co content of 1 at.%;

[0048] Step 5: After the piezoelectric functional layer is deposited, Al is deposited at 1Pa and 0V. 2 O 3 The protective layer is prepared by sputtering, with a coating thickness of 1 μm and an insulation resistance greater than 100 MΩ;

[0049] Step 6: After the protective layer is prepared, a Co electrode layer with a thickness of 5 μm is deposited at 100° C. and 0.5 Pa, and the resistance is less than 1Ω.

[0050] Finally, a temperature sensing rod with an ultrasonic temperature sensor is obtained.

[0051] Embodiment 2:

[0052] The method for preparing the temperature sensing rod with the ultrasonic temperature sensor in this embodiment comprises the following steps:

[0053] Step 1: using a deformed aluminum alloy or a cast aluminum alloy with a length of 100 mm and a diameter of 10 mm as a substrate, processing a ring defect with a depth of 2 mm and a width of 1 mm on the surface of the substrate as an ultrasonic reflection defect, and the distance between the ultrasonic reflection defect and one end of the substrate is 100 mm;

[0054] Step 2: Place the substrate in a power supply with a positive voltage of 450 V, a negative voltage of 250 V, a positive and negative duty cycle of 30%, and a frequency of 500 Hz. 2 SiO 3 、Na 2 B 4 O 7 , NaOH and Na 3 AlO 3 Pulse micro-arc oxidation is carried out in a silicate and aluminate mixed electrolyte to form an anti-corrosion layer, and the oxidation time is 60 minutes;

[0055] Step 3: after the pulse micro-arc oxidation is completed, a Co crystallization induction layer with a thickness of 200 nm and a nanocrystalline size of 100 nm (002) orientation is deposited on the surface of the anti-corrosion layer under an environment of a temperature of 300° C. and a pressure of 2 Pa;

[0056] Step 4: After the crystallization induction layer is deposited, a (002) oriented ZnCoO piezoelectric functional layer is deposited at 4Pa and 50V. The ZnCoO piezoelectric material is a Co-doped ZnO coating with a Co content of 10at.%;

[0057] Step 5: After the piezoelectric functional layer is deposited, Al is deposited at 3Pa and 200V. 2 O 3 The protective layer is prepared by sputtering, with a coating thickness of 5 μm and an insulation resistance greater than 100 MΩ;

[0058] Step 6: After the protective layer is prepared, a Co electrode layer with a thickness of 10 μm is deposited at 300° C. and 2 Pa, and the resistance is less than 1Ω.

[0059] Finally, a temperature sensing rod with an ultrasonic temperature sensor is obtained.

[0060] Embodiment 3:

[0061] The method for preparing the temperature sensing rod with the ultrasonic temperature sensor in this embodiment comprises the following steps:

[0062] Step 1: using a deformed aluminum alloy or a cast aluminum alloy with a length of 500 mm and a diameter of 80 mm as a substrate, processing a ring defect with a depth of 2 mm and a width of 0.8 mm on the surface of the substrate as an ultrasonic reflection defect, and the distance between the ultrasonic reflection defect and one end of the substrate is 50 mm;

[0063] Step 2: Place the substrate in a power supply with a positive voltage of 450 V, a negative voltage of 250 V, a positive and negative duty cycle of 20%, and a frequency of 500 Hz. 2 SiO 3 、Na 2 B 4 O 7 , NaOH and Na 3 AlO 3 Pulse micro-arc oxidation is carried out in a silicate and aluminate mixed electrolyte to form an anti-corrosion layer, and the oxidation time is 30 minutes;

[0064] Step 3, after the pulse micro-arc oxidation is completed, a Co crystallization induction layer with a thickness of 100 nm and a nanocrystalline size of 50 nm (002) orientation is deposited on the surface of the anti-corrosion layer under an environment of a temperature of 200° C. and a pressure of 1 Pa;

[0065] Step 4: After the crystallization induction layer is deposited, a (002) oriented ZnCoO piezoelectric functional layer is deposited at 1Pa and 20V. The ZnCoO piezoelectric material is a Co-doped ZnO coating with a Co content of 5at.%;

[0066] Step 5: After the piezoelectric functional layer is deposited, Al is deposited at 2Pa ​​and 100V. 2 O 3 The protective layer is prepared by sputtering, with a coating thickness of 2 μm and an insulation resistance greater than 100 MΩ;

[0067] Step 6: After the protective layer is prepared, a Co electrode layer with a thickness of 8 μm is deposited at 200° C. and 1 Pa, and the resistance is less than 1Ω.

[0068] Finally, a temperature sensing rod with an ultrasonic temperature sensor is obtained.

[0069] Embodiment 4:

[0070] The method for preparing the temperature sensing rod with the ultrasonic temperature sensor in this embodiment comprises the following steps:

[0071] Step 1: using a deformed aluminum alloy or a cast aluminum alloy with a length of 600 mm and a diameter of 60 mm as a substrate, processing a ring defect with a depth of 2 mm and a width of 1 mm on the surface of the substrate as an ultrasonic reflection defect, and the distance between the ultrasonic reflection defect and one end of the substrate is 60 mm;

[0072] Step 2: Place the substrate in a power supply with a positive voltage of 450 V, a negative voltage of 250 V, a positive and negative duty cycle of 15%, and a frequency of 500 Hz. 2 SiO 3 、Na 2 B 4 O 7 , NaOH and Na 3 AlO 3 Pulse micro-arc oxidation is carried out in a silicate and aluminate mixed electrolyte to form an anti-corrosion layer, and the oxidation time is 30 minutes;

[0073] Step 3: After the pulse micro-arc oxidation is completed, a Co crystallization induction layer with a thickness of 100 nm and a nanocrystalline size of 80 nm (002) orientation is deposited on the surface of the anti-corrosion layer under an environment of a temperature of 150° C. and a pressure of 1 Pa;

[0074] Step 4: After the crystallization induction layer is deposited, a (002) oriented ZnCoO piezoelectric functional layer is deposited at 1Pa and 40V. The ZnCoO piezoelectric material is a Co-doped ZnO coating with a Co content of 5at.%;

[0075] Step 5: After the piezoelectric functional layer is deposited, Al is deposited at 1Pa and 100V. 2 O 3 The protective layer is prepared by sputtering, with a coating thickness of 1 μm and an insulation resistance greater than 100 MΩ;

[0076] Step 6: After the protective layer is prepared, a Co electrode layer with a thickness of 6 μm is deposited at 200° C. and 1 Pa, and the resistance is less than 1Ω.

[0077] Finally, a temperature sensing rod with an ultrasonic temperature sensor is obtained.

[0078] Embodiment 5:

[0079] The method for preparing the temperature sensing rod with the ultrasonic temperature sensor in this embodiment comprises the following steps:

[0080] Step 1: using a deformed aluminum alloy or a cast aluminum alloy with a length of 90 mm and a diameter of 9 mm as a substrate, processing a ring defect with a depth of 1 mm and a width of 0.5 mm on the surface of the substrate as an ultrasonic reflection defect, and the distance between the ultrasonic reflection defect and one end of the substrate is 90 mm;

[0081] Step 2: Place the substrate in a power supply with a positive voltage of 450 V, a negative voltage of 250 V, a positive and negative duty cycle of 30%, and a frequency of 500 Hz. 2 SiO 3 、Na 2 B 4 O 7 , NaOH and Na 3 AlO 3 Pulse micro-arc oxidation is carried out in a silicate and aluminate mixed electrolyte to form an anti-corrosion layer, and the oxidation time is 60 minutes;

[0082] Step 3: after the pulse micro-arc oxidation is completed, a Co crystallization induction layer with a thickness of 50 nm and a nanocrystalline size of 50 nm (002) orientation is deposited on the surface of the anti-corrosion layer under an environment of a temperature of 100° C. and a pressure of 0.5 Pa;

[0083] Step 4: After the crystallization induction layer is deposited, a (002) oriented ZnCoO piezoelectric functional layer is deposited at 3Pa and 40V. The ZnCoO piezoelectric material is a Co-doped ZnO coating with a Co content of 8at.%;

[0084] Step 5: After the piezoelectric functional layer is deposited, Al is deposited at 1Pa and 100V. 2 O 3The protective layer is prepared by sputtering, with a coating thickness of 1 μm and an insulation resistance greater than 100 MΩ;

[0085] Step 6: After the protective layer is prepared, a Co electrode layer with a thickness of 10 μm is deposited at 300° C. and 2 Pa, and the resistance is less than 1Ω.

[0086] Finally, a temperature sensing rod with an ultrasonic temperature sensor is obtained.

[0087] The utility model is further described above with the help of specific embodiments, but it should be understood that the specific description here should not be construed as limiting the essence and scope of the utility model. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the utility model.

Claims

1. An ultrasonic temperature sensor, characterized in that: The sensor comprises an anti-corrosion layer, a crystallization induction layer, a piezoelectric functional layer, a protective layer and an electrode layer which are sequentially arranged on the surface of a substrate from the inside to the outside, and the piezoelectric functional layer is a ZnCoO coating.

2. An ultrasonic temperature sensor according to claim 1, characterized in that: The piezoelectric functional layer is a (002) oriented columnar crystal ZnCoO coating.

3. The ultrasonic temperature sensor according to claim 1, characterized in that: The anti-corrosion layer is an aluminum oxide layer, and the thickness of the anti-corrosion layer is 10 to 100 μm.

4. The ultrasonic temperature sensor according to claim 1, characterized in that: The crystal induction layer is a (002) oriented Co nanocrystalline layer, and the nanocrystalline size of the induction layer is 10-100nm and the thickness is 50-200nm.

5. The ultrasonic temperature sensor according to claim 1, characterized in that: The protective layer is an aluminum oxide layer, and the thickness of the protective layer is 10 to 100 μm.

6. The ultrasonic temperature sensor according to claim 1, characterized in that: The electrode layer is a Co layer, and the thickness of the electrode layer is 5-10 μm.

7. A temperature sensing rod, characterized in that: The ultrasonic temperature sensor comprises a substrate and an ultrasonic temperature sensor as claimed in any one of claims 1 to 6 mounted on an end surface of the substrate.

8. A temperature sensing rod according to claim 7, characterized in that: The substrate is a cylinder made of deformed aluminum alloy or cast aluminum alloy, and the length of the substrate is 50 to 1000 mm and the diameter is 5 to 10 mm.

9. A temperature sensing rod according to claim 7, characterized in that: An annular ultrasonic reflection defect is formed on the outer circumferential surface of the substrate at a distance of 5 to 100 mm from one end thereof far away from the piezoelectric functional layer; the ultrasonic reflection defect has a depth of 1 to 2 mm and a width of 0.5 to 1 mm.

10. A temperature sensing rod according to claim 9, characterized in that: The central axis of the annular ultrasonic reflection defect coincides with the central axis of the substrate.

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