An ultrasonic oblique probe and a method for manufacturing the same

Abstract

The present application relates to the field of nondestructive testing, and more particularly to an ultrasonic oblique probe and a preparation method thereof. The probe comprises: a wedge, a cavity is arranged in the wedge, and a piezoelectric wafer is arranged in the cavity; a gap of the cavity is filled with a high-temperature coupling agent; a head of the wedge has an oblique angle; the piezoelectric wafer comprises PN piezoelectric ceramic, positive and negative electrode layers are arranged at two ends of the PN piezoelectric ceramic respectively; an adhesive layer is arranged between the negative electrode layer and a backing block; the adhesive layer is prepared by a gradient curing method using inorganic-organic hybrid adhesive; the inorganic-organic hybrid adhesive maintains stable bonding strength and acoustic impedance matching at >= 300 DEG C; a threaded cover plate tightly fixes the backing block in the wedge; the backing block material is a tungsten powder-epoxy resin-ceramic microsphere three-phase composite system; and the wedge is made of aramid fiber reinforced polyimide resin matrix composite material. The present application is suitable for nondestructive testing of high-temperature pipelines.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing, and more particularly to an ultrasonic angle probe and its preparation method. Background Technology

[0002] Leaks in high-temperature pipelines in the conventional island of nuclear power plants are a common problem. For nuclear power plants, this directly affects the safe and stable operation of the units. If a leak leads to a shutdown or reactor shutdown, it will cause serious economic losses. High-temperature pipelines in the conventional island of nuclear power plants are usually inspected after the insulation has been removed and the system has cooled down while the unit is shut down. However, for online inspection of insulated high-temperature pipelines during unit operation, it is crucial to promptly identify potential defects without shutting down the system, evaluate the defects, predict the availability of the pipelines or systems, determine the timing of maintenance, and improve the safety of unit operation. Currently, the domestic nuclear power non-destructive testing industry lacks effective solutions for this.

[0003] Currently, domestic power plants typically employ two methods when facing pipeline leaks (steam or water) in operating units. First, under the premise of avoiding shutdown or reducing operating pressure and temperature, pressurized leak sealing operations are usually performed, primarily involving sealing the leak and installing clamps. However, if the pipe thinning or weld defects in the leak area are not understood before sealing and installing clamps, direct operation may lead to the expansion of defects, causing burns to personnel, and in severe cases, even pipe bursts, directly threatening the lives of on-site workers. Second, the power output of the nuclear power plant unit is usually reduced to allow the fluid temperature inside the pipeline to drop to a lower level before using conventional thickness gauges for detection. However, this wastes a significant amount of time and puts considerable pressure on the nuclear power plant's operation, potentially resulting in economic losses. Currently, there are no effective detection methods in China for high-temperature pipeline leaks and surrounding areas. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide an ultrasonic angle probe and its manufacturing method.

[0005] This invention provides an ultrasonic angle probe, comprising:

[0006] A wedge block, wherein a cavity is provided inside the wedge block, and a piezoelectric wafer is disposed inside the cavity; the gap of the cavity is filled with a high-temperature coupling agent; the head of the wedge block has an inclined angle;

[0007] The piezoelectric wafer includes a PN piezoelectric ceramic, with a positive electrode layer and a negative electrode layer respectively disposed at both ends of the PN piezoelectric ceramic;

[0008] An adhesive layer is disposed between the negative electrode layer and the backing block; the adhesive layer is prepared by an inorganic-organic hybrid adhesive through a gradient curing method; the inorganic-organic hybrid adhesive maintains stable bonding strength and acoustic impedance matching at ≥300℃;

[0009] The threaded cover plate presses and fixes the backing block inside the wedge block;

[0010] The backing block material is a three-phase composite system of tungsten powder-epoxy resin-ceramic microspheres; the wedge is made of aramid fiber reinforced polyimide resin matrix composite material.

[0011] In a specific embodiment of the present invention, the preparation method of the aramid fiber reinforced polyimide resin-based composite material is as follows:

[0012] Step S1: Graft modification of aramid fibers using toluene diisocyanate to obtain modified aramid fibers;

[0013] Step S2: Place the modified aramid fiber in a polyamic acid solution for graft modification to obtain a precursor solution;

[0014] Step S3: The precursor solution is subjected to gradient curing to obtain an aramid fiber reinforced polyimide resin composite material;

[0015] The gradient curing method is as follows: first, the temperature is raised to 330~340℃ and left to stand for N1 hours; then the temperature is raised to 350~360℃ and left to stand for N2 hours; finally, the temperature is raised to 370~380℃ and left to stand for N3 hours, and the sum of N1, N2 and N3 is 1~1.5 hours.

[0016] In one specific embodiment of the present invention, the components of the tungsten powder-epoxy resin-ceramic microsphere three-phase composite system are mixed in the following mass percentages:

[0017] Tungsten powder: 60wt%~70wt%;

[0018] Epoxy resin: 25wt%~35wt%;

[0019] Ceramic microspheres: 5wt%~10wt%;

[0020] The amount of nano-alumina-modified methyltetrahydrophthalic anhydride added is 30% to 40% of the epoxy resin mass.

[0021] 2-Ethyl-4-methylimidazolium is added at a rate of 1% to 2% of the mass of the nano-alumina-modified methyltetrahydrophthalic anhydride.

[0022] In one specific embodiment of the present invention, lead wire grooves are symmetrically arranged on both sides of the backing block, and the negative lead wire and the positive lead wire are connected to the cable outside the probe through the lead wire grooves.

[0023] This invention provides a method for preparing an ultrasonic angle probe, comprising the following steps:

[0024] Step 1: Create a cavity inside the wedge made of aramid fiber reinforced polyimide resin matrix composite material, and inject a high-temperature coupling agent into the cavity;

[0025] Step 2: The piezoelectric wafer is installed into the cavity;

[0026] Step 3: The backing block is installed into the cavity and placed on the negative electrode layer of the piezoelectric wafer; an adhesive layer is placed between the negative electrode layer and the backing block; the adhesive layer is prepared by an organic-inorganic hybrid adhesive through a gradient curing method; the backing block material is a three-phase composite system of tungsten powder-epoxy resin-ceramic microspheres.

[0027] Step 4: Screw the threaded cover into the wedge, and use the pressure of the threaded cover to press the backing block, piezoelectric wafer, and bottom of the cavity together.

[0028] In one specific embodiment of the present invention, the piezoelectric wafer.

[0029] In a specific embodiment of the present invention, step 3 specifically comprises:

[0030] An inorganic-organic hybrid adhesive is coated onto the negative electrode layer of the piezoelectric wafer;

[0031] Insert the backing block;

[0032] Pre-curing is performed at 70~90℃, cross-linking is carried out at 140~160℃, and final curing is performed at 240~260℃.

[0033] In one specific embodiment of the present invention, the method for preparing the backing block is as follows:

[0034] Mix the components according to the following mass percentages:

[0035] Tungsten powder: 60wt%~70wt%;

[0036] Epoxy resin: 25wt%~35wt%;

[0037] Ceramic microspheres: 5wt%~10wt%;

[0038] The amount of nano-alumina-modified methyltetrahydrophthalic anhydride added is 30% to 40% of the epoxy resin mass.

[0039] 2-Ethyl-4-methylimidazolium, added at a rate of 1% to 2% of the mass of nano-alumina-modified methyltetrahydrophthalic anhydride;

[0040] The backing block is obtained by curing in stages at 180~200℃.

[0041] In one specific embodiment of the present invention, the piezoelectric wafer includes a positive electrode layer, a negative electrode layer, and piezoelectric ceramic;

[0042] The piezoelectric wafer is prepared by sintering lead zirconate titanate material at a high temperature above 1200℃ and then cutting it into thin sheets, which are then ground to the required thickness. Electrodes are deposited on the surface of the thin sheets by magnetron sputtering or silver burning, with a thickness of 5~10μm, to form a positive electrode layer and a negative electrode layer.

[0043] In one specific embodiment of the present invention, the contact surface between the backing block and the negative electrode layer is structurally processed to increase the contact area.

[0044] Compared with the prior art, the ultrasonic angle probe and its preparation method of the present invention have the following beneficial effects:

[0045] (1) Through the design of high-temperature resistant materials and precision manufacturing processes, the reliability, stability and efficiency of online pipeline inspection in the nuclear power industry have been significantly improved;

[0046] (2) The wedge is made of aramid fiber reinforced polyimide resin matrix composite material, replacing traditional rubber or ordinary plastic, to avoid high temperature softening and deformation; the piezoelectric chip is placed inside the wedge and filled with high temperature coupling agent, which effectively isolates the acoustic components from the surrounding high temperature environment, thereby protecting the acoustic components from damage and extending the working time of the probe; it ensures good coupling between the wedge and the piezoelectric chip and other acoustic components, and ensures the reliability of sound transmission and test results;

[0047] (3) The innovative high-temperature bonding process between the backing block and the piezoelectric wafer ensures long-term acoustic performance stability and meets testing requirements;

[0048] In summary, this invention significantly improves the detection performance and reliability of ultrasonic probes in high-temperature environments not exceeding 250°C through innovation in high-temperature resistant materials, structural optimization, and process improvement, and solves the core problems of traditional probes such as signal attenuation, coupling failure, and insufficient lifespan under high-temperature conditions. Attached Figure Description

[0049] Figure 1 A schematic diagram showing the structure of an ultrasonic angle probe;

[0050] In the diagram: 1-wedge, 2-threaded cover, 3-cable, 4-backing block, 5-adhesive layer, 6-negative electrode layer, 7-PN piezoelectric ceramic, 8-positive electrode layer, 9-negative lead, 10-positive lead. Detailed Implementation

[0051] To further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the present invention.

[0052] An embodiment of the present invention discloses an ultrasonic angle probe, comprising:

[0053] A wedge 1 has a cavity inside, and a piezoelectric wafer is disposed inside the cavity; the gap of the cavity is filled with a high-temperature coupling agent; the head of the wedge 1 has an inclined angle;

[0054] The piezoelectric wafer includes a PN piezoelectric ceramic 7, with a positive electrode layer 8 and a negative electrode layer 6 respectively disposed at both ends of the PN piezoelectric ceramic 7;

[0055] An adhesive layer 5 is disposed between the negative electrode layer 6 and the backing block 4; the adhesive layer 5 is prepared by an inorganic-organic hybrid adhesive through a gradient curing method; the inorganic-organic hybrid adhesive maintains stable bonding strength and acoustic impedance matching at ≥300℃;

[0056] The threaded cover plate 2 presses and fixes the backing block 4 into the wedge block 1;

[0057] The material of the backing block 4 is a three-phase composite system of tungsten powder-epoxy resin-ceramic microspheres; the wedge block 1 is made of aramid fiber reinforced polyimide resin matrix composite material.

[0058] The preparation method of the aramid fiber reinforced polyimide resin-based composite material is as follows:

[0059] Step S1: Graft modification of aramid fibers using toluene diisocyanate to obtain modified aramid fibers;

[0060] Specifically, it includes:

[0061] The aramid fibers are subjected to ultrasonic treatment in a strongly polar aprotic solution for 5 to 10 minutes.

[0062] Toluene diisocyanate is added to a strongly polar aprotic solution and treated at 60-70°C for 0.5-1 hour, preferably at 61-65°C for 0.5-1-0.8 hours; the ratio of the amount of toluene diisocyanate to aramid fiber added is (0.05-0.1) mol: 1 g.

[0063] After processing, the fibers are washed and dried to obtain modified aramid fibers.

[0064] The longer the aramid fiber, the greater its stiffness and the greater its reinforcing effect. However, excessively long aramid fibers are prone to clumping and entanglement, making uniform dispersion difficult and weakening the interfacial bonding with the subsequent polyimide, thus reducing the mechanical properties of the composite material. Furthermore, the amount of aramid fiber added needs to be controlled; too little will result in limited reinforcing effect, while too much will lead to uneven dispersion and a decrease in the mechanical properties of the composite material. The preferred length of the aramid fiber is 8-12 mm.

[0065] The strongly polar aprotic solvent is one or a mixture of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, and N-methylpyrrolidone.

[0066] Step S2: Place the modified aramid fiber in a polyamic acid solution for graft modification to obtain a precursor solution;

[0067] The polyamic acid solution is prepared by a polycondensation reaction of a diamine monomer, a dianhydride monomer, and benzoic acid to obtain the polyamic acid solution; the molar ratio of the diamine monomer, the dianhydride monomer, and benzoic acid is 1:(0.1~1):(0.1~0.5).

[0068] The polycondensation reaction takes 2 to 72 hours, preferably 20 to 50 hours; the reaction temperature is 0 to 40°C, preferably 20 to 30°C.

[0069] The mass of the aramid fiber is a, and the sum of the masses of the diamine monomer and the dianhydride monomer is b, where a:b = 5~10:100.

[0070] The diamine monomer is an aromatic diamine, specifically m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, or p-phenylenediamine sulfonate. , , , , and At least one of them;

[0071] The dianhydride monomer is an aromatic dianhydride, specifically pyromellitic dianhydride, biphenyl dianhydride, or 3,3',4,4'-benzophenone tetracarboxylic dianhydride. , , , , and At least one of them.

[0072] Step S3: The precursor solution is subjected to gradient curing to obtain an aramid fiber reinforced polyimide resin composite material;

[0073] The gradient curing method is as follows: first, the temperature is raised to 330~340℃ and left to stand for N1 hours; then the temperature is raised to 350~360℃ and left to stand for N2 hours; finally, the temperature is raised to 370~380℃ and left to stand for N3 hours, and the sum of N1, N2 and N3 is 1~1.5 hours.

[0074] The gradient curing is carried out under a vacuum pressure of 0.1-0.3 MPa.

[0075] The wedge material used in this invention has a slow change in sound velocity with temperature.

[0076] The head of the wedge 1 has an inclined angle; based on the sound velocity of the wedge material, the sound velocity of the material being measured, and the required refraction angle, the incident angle of the wedge material can be calculated, thereby determining the wedge inclination angle parameters and external dimensions. This invention is applicable to pipelines with a maximum temperature of 250℃, using an angled probe with a main beam angle of 63.4°. The angled probe is designed based on the sound velocity calculation at the highest temperature and the external dimensions of the pipeline being inspected.

[0077] The piezoelectric wafer used in this invention includes a positive electrode layer 8, a negative electrode layer 6, and a PN piezoelectric ceramic 7;

[0078] The Curie temperature of the PN piezoelectric ceramic 7 should be greater than 300℃ to ensure that the piezoelectric wafer does not depolarize at high temperatures, thus preventing performance loss.

[0079] The piezoelectric wafer is prepared by sintering lead zirconate titanate material at a high temperature above 1200℃ and then cutting it into thin sheets, which are then ground to the required thickness. Electrodes are deposited on the surface of the thin sheets by magnetron sputtering or silver deposition, with a thickness of 5~10μm, forming a positive electrode layer 8 and a negative electrode layer 6.

[0080] Positive electrode layer 8 is welded with positive electrode lead 10, and negative electrode layer 6 is welded with negative electrode lead 9;

[0081] Negative lead 9 and positive lead 10 are made of silver-plated copper wire with a diameter of 0.1 mm and are covered with a polyimide insulating layer.

[0082] The backing block 4 has symmetrical lead grooves on both sides, and the negative lead 9 and the positive lead 10 are connected to the cable 3 outside the probe through the lead grooves.

[0083] The material of the backing block 4 is a three-phase composite system of tungsten powder, epoxy resin, and ceramic microspheres, and the components are mixed in the following mass percentages:

[0084] Tungsten powder: 60wt%~70wt%, preferably 65wt%;

[0085] Epoxy resin: 25wt%~35wt%, preferably 30wt%;

[0086] Ceramic microspheres: 5wt%~10wt%, preferably 5wt%;

[0087] The amount of nano-alumina-modified methyltetrahydrophthalic anhydride added is 30% to 40% of the epoxy resin mass.

[0088] 2-Ethyl-4-methylimidazole is added at a rate of 1% to 2% of the mass of the nano-alumina-modified methyltetrahydrophthalic anhydride; 2-Ethyl-4-methylimidazole acts as an accelerator to speed up the curing reaction.

[0089] The tungsten powder is a high-density phase with a particle size of 1~10μm and a purity of ≥99.5%.

[0090] The epoxy resin is the matrix phase, preferably a bisphenol A type epoxy resin with an epoxy value of 0.51~0.54;

[0091] The ceramic microspheres are low-density phases, specifically hollow alumina microspheres with a particle size of 20-50 μm, a wall thickness of 1-2 μm, and a density of 0.6-0.8 g / cm³.

[0092] The curing agent is methyltetrahydrophthalic anhydride modified with nano-alumina. The preparation method of methyltetrahydrophthalic anhydride modified with nano-alumina is as follows: nano-alumina with a particle size of 30~50nm is added to methyltetrahydrophthalic anhydride, and after ultrasonic dispersion and uniform mixing, methyltetrahydrophthalic anhydride modified with nano-alumina is obtained.

[0093] The ultrasonic dispersion power is 290~350W, and the time is 20~40 minutes.

[0094] The nano-alumina accounts for 5% to 8% of the total mass of the curing agent.

[0095] An embodiment of the present invention provides a method for preparing an ultrasonic angle probe, comprising the following steps:

[0096] Step 1: Create a cavity inside the wedge 1 made of aramid fiber reinforced polyimide resin matrix composite material, and inject a high-temperature coupling agent into the cavity;

[0097] The preparation method of aramid fiber reinforced polyimide resin matrix composite material is as described in the above technical solution;

[0098] The high-temperature coupling agent is a silicon-based nanofluid that can withstand temperatures above 300°C.

[0099] Inject 3-5 ml of the high-temperature coupling agent to ensure that there is no air in the cavity;

[0100] Step 2: The piezoelectric wafer is installed into the cavity;

[0101] Specifically, it includes:

[0102] Preparation of piezoelectric wafers: Lead zirconate titanate material is sintered at a high temperature above 1200℃ and then cut into thin sheets, which are then ground to the frequency thickness; electrodes are deposited on the surface of the thin sheets by magnetron sputtering or silver burning process, with a thickness of 5~10μm, forming a positive electrode layer 8 and a negative electrode layer 6.

[0103] Positive electrode layer 8 is welded with positive electrode lead 10, and negative electrode layer 6 is welded with negative electrode lead 9;

[0104] The piezoelectric wafer with soldered leads is installed in the cavity. The process between the piezoelectric wafer and the wedge block breaks away from the conventional epoxy adhesive process and instead utilizes the coupling effect of the high-temperature coupling agent to achieve assembly and sound transmission.

[0105] Step 3: Insert the backing block 4 into the cavity, located on the negative electrode layer of the piezoelectric wafer; an adhesive layer is placed between the negative electrode layer and the backing block; the adhesive layer is prepared by an organic-inorganic hybrid adhesive through a gradient curing method; the backing block material is a three-phase composite system of tungsten powder-epoxy resin-ceramic microspheres.

[0106] Specifically, the following steps are included:

[0107] Step 3-1: Coat the negative electrode layer 6 of the piezoelectric wafer with an inorganic-organic hybrid adhesive; the organic-inorganic hybrid adhesive is a silicate-polyimide composite material;

[0108] Step 3-2: Insert backing block 4;

[0109] The backing block 4 is prepared by:

[0110] Mix the components according to the following mass percentages:

[0111] Tungsten powder: 60wt%~70wt%;

[0112] Epoxy resin: 25wt%~35wt%;

[0113] Ceramic microspheres: 5wt%~10wt%;

[0114] The amount of nano-alumina-modified methyltetrahydrophthalic anhydride added is 30% to 40% of the epoxy resin mass.

[0115] 2-Ethyl-4-methylimidazolium, added at a rate of 1% to 2% of the mass of nano-alumina-modified methyltetrahydrophthalic anhydride;

[0116] The backing block is obtained by curing in stages at 180~200℃.

[0117] When processing the backing block 4, one lead groove is processed on each of the symmetrical sides to facilitate the connection of the negative lead 9 and the positive lead 10 to the cable 3 outside the probe through the lead groove.

[0118] Step 3-3: Pre-curing treatment at 70~90℃, cross-linking at 140~160℃, and final curing at 240~260℃; more preferably, pre-curing treatment at 80℃, cross-linking at 150℃, and final curing at 250℃.

[0119] The contact surface between the backing block and the negative electrode layer is structurally treated to increase the contact area and form a mechanical interlock. Combined with plasma activation to improve wettability, the shear strength is increased by more than 40%.

[0120] Step 4: Screw the threaded cover plate 2 into the wedge block 1, and use the pressure of the threaded cover plate 2 to press the backing block 4, the piezoelectric wafer, and the bottom of the cavity tightly.

[0121] The ultrasonic angle probe prepared by the present invention was subjected to performance tests, including a high-temperature environment stability test at 250°C and online detection in a nuclear power pipeline using the angle probe.

[0122] Table 1 shows the results of stability tests at a high temperature of 250℃.

[0123]

[0124] The results of online inspection inside nuclear power plant pipelines using the aforementioned angle probe are as follows:

[0125] Testing environment: Main steam pipeline of a nuclear power plant, pipeline temperature 230℃;

[0126] Test results: The defect detection rate was 98%, the false alarm rate was <1%, and the performance did not degrade after 18 months of continuous operation.

[0127] The measured data are compared with those of existing probes, as shown in Table 2.

[0128] Table 2 Comparison of Measured Data

[0129]

[0130] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0131] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An ultrasonic angle probe, characterized in that, include: A wedge block, wherein a cavity is provided inside the wedge block, and a piezoelectric wafer is disposed inside the cavity; the gap of the cavity is filled with a high-temperature coupling agent; the head of the wedge block has an inclined angle; The piezoelectric wafer includes lead zirconate titanate piezoelectric ceramic, with a positive electrode layer and a negative electrode layer respectively disposed at both ends of the lead zirconate titanate piezoelectric ceramic; An adhesive layer is disposed between the negative electrode layer and the backing block; the adhesive layer is prepared by an inorganic-organic hybrid adhesive through a gradient curing method; the inorganic-organic hybrid adhesive maintains stable bonding strength and acoustic impedance matching at ≥300℃; The threaded cover plate presses and fixes the backing block inside the wedge block; The backing block material is a three-phase composite system of tungsten powder-epoxy resin-ceramic microspheres; the wedge is made of aramid fiber reinforced polyimide resin matrix composite material. The preparation method of the aramid fiber reinforced polyimide resin-based composite material is as follows: Step S1: Graft modification of aramid fibers using toluene diisocyanate to obtain modified aramid fibers; Step S2: The modified aramid fiber is placed in a polyamic acid solution for graft modification to obtain a precursor solution; The polyamic acid solution is prepared by a polycondensation reaction of a diamine monomer, a dianhydride monomer, and benzoic acid to obtain the polyamic acid solution; the molar ratio of the diamine monomer, the dianhydride monomer, and benzoic acid is 1:(0.1~1):(0.1~0.5). Step S3: The precursor solution is subjected to gradient curing to obtain an aramid fiber reinforced polyimide resin composite material; The gradient curing method is as follows: first, the temperature is raised to 330~340℃ and left to stand for N1 hours; then the temperature is raised to 350~360℃ and left to stand for N2 hours; finally, the temperature is raised to 370~380℃ and left to stand for N3 hours, and the sum of N1, N2 and N3 is 1~1.5 hours.

2. The ultrasonic angle probe according to claim 1, characterized in that, The tungsten powder-epoxy resin-ceramic microsphere three-phase composite system is composed of the following components mixed in the following mass percentages: Tungsten powder: 60wt%~70wt%; Epoxy resin: 25wt%~35wt%; Ceramic microspheres: 5wt%~10wt%; The amount of nano-alumina-modified methyltetrahydrophthalic anhydride added is 30% to 40% of the epoxy resin mass. 2-Ethyl-4-methylimidazolium is added at a rate of 1% to 2% of the mass of the nano-alumina-modified methyltetrahydrophthalic anhydride.

3. The ultrasonic angle probe according to claim 1, characterized in that, The backing block is symmetrically provided with lead wire grooves on both sides, and the negative lead wire and the positive lead wire are connected to the cable outside the probe through the lead wire grooves.

4. A method for preparing an ultrasonic angle probe as described in claim 1, characterized in that, Includes the following steps: Step 1: Create a cavity inside the wedge made of aramid fiber reinforced polyimide resin matrix composite material, and inject a high-temperature coupling agent into the cavity; Step 2: The piezoelectric wafer is installed into the cavity; Step 3: Insert the backing block into the cavity, located on the negative electrode layer of the piezoelectric wafer; an adhesive layer is placed between the negative electrode layer and the backing block; the adhesive layer is prepared by an inorganic-organic hybrid adhesive through a gradient curing method; the backing block material is a three-phase composite system of tungsten powder-epoxy resin-ceramic microspheres. Step 4: Screw the threaded cover into the wedge, and use the pressure of the threaded cover to press the backing block, piezoelectric wafer, and bottom of the cavity together.

5. The method for preparing an ultrasonic angle probe according to claim 4, characterized in that, Step 3 specifically involves: An inorganic-organic hybrid adhesive is coated onto the negative electrode layer of the piezoelectric wafer; Insert the backing block; Pre-curing is performed at 70~90℃, cross-linking is carried out at 140~160℃, and final curing is performed at 240~260℃.

6. The method for preparing an ultrasonic angle probe according to claim 5, characterized in that, The method for preparing the backing block is as follows: Mix the components according to the following mass percentages: Tungsten powder: 60wt%~70wt%; Epoxy resin: 25wt%~35wt%; Ceramic microspheres: 5wt%~10wt%; The amount of nano-alumina-modified methyltetrahydrophthalic anhydride added is 30% to 40% of the epoxy resin mass. 2-Ethyl-4-methylimidazolium, added at a rate of 1% to 2% of the mass of nano-alumina-modified methyltetrahydrophthalic anhydride; The backing block is obtained by curing in stages at 180~200℃.

7. The method for preparing an ultrasonic angle probe according to claim 4, characterized in that, The piezoelectric wafer includes a positive electrode layer, a negative electrode layer, and piezoelectric ceramic. The piezoelectric wafer is prepared by sintering lead zirconate titanate material at a high temperature above 1200℃ and then cutting it into thin sheets, which are then ground to the required thickness. Electrodes are deposited on the surface of the thin sheets by magnetron sputtering or silver burning, with a thickness of 5~10μm, to form a positive electrode layer and a negative electrode layer.

8. The method for preparing an ultrasonic angle probe according to claim 4, characterized in that, The contact surface between the backing block and the negative electrode layer is structurally processed to increase the contact area.

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