CN-121994935-A - Laminated multi-mode ultrasonic phased array probe and preparation method thereof

CN121994935ACN 121994935 ACN121994935 ACN 121994935ACN-121994935-A

Abstract

The invention discloses a laminated multi-mode ultrasonic phased array probe and a preparation method thereof, wherein the laminated multi-mode ultrasonic phased array probe provided by the invention adopts a mode of vertically stacking a low-frequency piezoelectric array and a high-frequency piezoelectric array element up and down, and a frequency selection isolation layer is arranged between the low-frequency piezoelectric array and the high-frequency piezoelectric array, wherein the low-frequency piezoelectric array element and the high-frequency piezoelectric array element are respectively and independently selected from nonlinear piezoelectric array elements or linear piezoelectric array elements, so that the piezoelectric array elements in the high-frequency piezoelectric array are used as a first matching layer of low-frequency signals, the high-frequency transmitting array elements are used as high-efficiency transmission channels of low-frequency receiving signals at the same time, and the complex impedance transition is realized by depending on a second matching layer at the lowest end, thereby fundamentally optimizing the transmission path of the low-frequency nonlinear signals, reducing the reflection loss of the low-frequency nonlinear signals at the front end of the penetration probe by more than 60%, and remarkably improving the receiving sensitivity.

Inventors

CHENG LIJIN
Sha Boyu
HAO PENGXIANG
LIU YAOLU
CHENG E
HU NING

Assignees

河北工业大学

Dates

Publication Date: 20260508
Application Date: 20260202

Claims (10)

1. The laminated multimode ultrasonic phased array probe is characterized by comprising a backing layer, a low-frequency piezoelectric array formed by low-frequency piezoelectric array elements, a frequency selection isolation layer, a high-frequency piezoelectric array formed by high-frequency piezoelectric array elements and a second matching layer from top to bottom; The low-frequency piezoelectric array element and the high-frequency piezoelectric array element are respectively and independently selected from nonlinear piezoelectric array elements or linear piezoelectric array elements, and the low-frequency piezoelectric array element and the high-frequency piezoelectric array element are not nonlinear piezoelectric array elements or linear piezoelectric array elements at the same time; The high-frequency piezoelectric array is used as a first matching layer of a low-frequency signal at the same time, and the thickness t h of the high-frequency piezoelectric array is obtained by the formula (1): t h =1/4λ l formula (1); Wherein lambda l is the wavelength of the low-frequency piezoelectric array element; The upper surface and the lower surface of the frequency selection isolation layer are respectively provided with clamping grooves for inserting the low-frequency piezoelectric array elements and the high-frequency piezoelectric array elements at intervals, the surface of any clamping groove is provided with a micro-channel, and the micro-channel is used as an embedded channel of a vertical electrical interconnection structure and a positioning reference of the low-frequency piezoelectric array elements and the high-frequency piezoelectric array elements.
2. The laminated multimode ultrasonic phased array probe of claim 1, wherein the linear piezoelectric array element is used for transmitting and receiving fundamental frequency ultrasonic signals, and the nonlinear piezoelectric array element is used for receiving nonlinear harmonic signals, including zero frequency signals and frequency doubling signals; The working frequency of the linear piezoelectric array element is 2 MHz-5 MHz, the working frequency of the nonlinear piezoelectric array element is 0.1 MHz-1 MHz when receiving a zero frequency signal, and the working frequency of the nonlinear piezoelectric array element is 4 MHz-15 MHz when receiving a frequency doubling signal; The lengths of the low-frequency piezoelectric array elements and the high-frequency piezoelectric array elements are 10 mm-15 mm; The space between any two low-frequency piezoelectric array elements or any two high-frequency piezoelectric array elements is 0.1-0.3 mm; The thickness of the nonlinear piezoelectric array element is 0.5 mm-1.3 mm, the thickness of the nonlinear piezoelectric array element is 3 mm-5 mm when receiving zero frequency signals, and the thickness of the nonlinear piezoelectric array element is 0.1 mm-0.65 mm when receiving frequency doubling signals; the low-frequency piezoelectric array element and the high-frequency piezoelectric array element are PZT piezoelectric wafers with Ag electrodes coated on the surfaces; the backing layer is made of an epoxy resin mixture with tungsten powder as a filler.
3. The laminated multi-mode ultrasonic phased array probe of claim 1, wherein: The micro-flow channel is arranged on the central axis of the clamping groove of the frequency selective isolation layer, is semicircular, has the diameter of 90-110 mu m and has the dimensional tolerance of less than or equal to 10 mu m; the material of the frequency selective isolation layer is transparent photosensitive resin; The thickness t i of the clamping groove in the frequency selective isolation layer is obtained by the formula (2): t i ≤1/4λ 2 formula (2); Wherein lambda 2 is the wavelength of the high-frequency piezoelectric array element.
4. The laminated multi-mode ultrasonic phased array probe of claim 1, wherein: The material of the second matching layer is Al 2 O 3 /epoxy resin composite material; the thickness d p of the second matching layer is obtained by formula (3): d p =λ m,h /(4f h ) formula (3); Wherein lambda m,h is the wavelength of the high-frequency signal in the measured material, and f h is the center frequency of the high-frequency piezoelectric array element; The acoustic impedance Z match of the material of the second matching layer is obtained by formula (4): z match =（0.98~1.02）Z m (4), wherein Z m is the acoustic impedance of the measured material.
5. The laminated multi-mode ultrasonic phased array probe of claim 1, wherein: the laminated multimode ultrasonic phased array probe further comprises a vertical interconnection electrode structure, and the vertical interconnection electrode structure is arranged in a micro-channel of the isolation layer.
6. A preparation method of a laminated multi-mode ultrasonic phased array probe is characterized in that slurry containing PZT ceramic powder is adopted to carry out photo-curing 3D printing based on a low-frequency piezoelectric array model containing a substrate A and a high-frequency piezoelectric array model containing a substrate B respectively to obtain a low-frequency piezoelectric array blank and a high-frequency piezoelectric array blank, degreasing, sintering, silver plating and polarizing are sequentially carried out to obtain a low-frequency piezoelectric array containing the substrate A and a high-frequency piezoelectric array containing the substrate B, photo-curing 3D printing is carried out by adopting the slurry of an isolation layer based on a model of a frequency selective isolation layer to obtain the frequency selective isolation layer, then a micro-channel of the frequency selective isolation layer is adopted as a positioning reference, the high-frequency piezoelectric array element, the frequency selective isolation layer and the low-frequency piezoelectric array element are sequentially aligned, and are bonded by resin glue, the substrate A and the substrate B are removed by polishing, and then a second matching layer and a backing layer are bonded.
7. The method for preparing the laminated multi-mode ultrasonic phased array probe according to claim 6, wherein the method comprises the following steps: Preparing PZT ceramic powder, a No. 1 photo-curing monomer and a No. 1 additive, mixing to obtain slurry containing the PZT ceramic powder, adding the slurry containing the PZT ceramic powder into photo-curing 3D printing equipment, and performing photo-curing 3D printing according to a low-frequency piezoelectric array model containing a substrate A and a high-frequency piezoelectric array model containing a substrate B to obtain a piezoelectric array element blank; The PZT ceramic powder consists of ceramic powder with the particle size of d 50 =0.25-1.5 mu m; in the slurry containing the PZT ceramic powder, the mass fraction of the PZT ceramic powder is 80-91 wt%, the mass fraction of the No.1 photo-curing monomer is 6-17 wt%, and the mass fraction of the No.1 additive is 1-5 wt%; the No.1 photo-curing monomer consists of dipentaerythritol hexaacrylate, polyethylene glycol o-phenyl ether acrylate and ethoxylated trimethylolpropane triacrylate, wherein the mass ratio of the dipentaerythritol hexaacrylate to the polyethylene glycol o-phenyl ether acrylate to the di-ethoxylated trimethylolpropane triacrylate is 5-10:60-80:10-15; The No. 1 additive consists of a dispersing agent, an anti-settling agent, a leveling agent, an antifoaming agent and a photoinitiator, wherein the dispersing agent comprises the anti-settling agent, the antifoaming agent comprises the photoinitiator=1-3:0.1-3:1-3:0.1-5, the dispersing agent is KMT3331, the anti-settling agent is Sago-8810, the leveling agent is Rad2500, the antifoaming agent is SRE-2022A, and the photoinitiator is 2,4, 6-trimethyl benzoyl ethyl phenylphosphonate; Mixing PZT ceramic powder, a No.1 photo-curing monomer and a No.1 additive in a mixer in a vacuum environment, wherein the mixing speed is 800-1800 rpm, and the mixing time is 5-30 min; When the photocuring 3D printing is performed on the high-frequency piezoelectric array blank and the high-frequency piezoelectric array blank, the exposure energy is controlled to be 8-30 mJ/cm 2 , and the thickness of the layer is controlled to be 10-30 mu m; The degreasing is carried out in a vacuum environment, the degreasing temperature is 400-600 ℃, and the degreasing time is 2500-3000 min; The sintering temperature is 1150-1250 ℃, and the sintering time is 1-3 hours; The polarization process is that a silver-coated sintered blank is placed in 120 ℃ silicone oil and subjected to polarization for 5-20 min in an electric field of 2-5 kV/mm.
8. The method for preparing the laminated multi-mode ultrasonic phased array probe according to claim 6, wherein the method comprises the following steps: The process of obtaining the frequency selective isolation layer by photo-curing 3D printing based on the model of the frequency selective isolation layer by adopting the isolation layer slurry comprises the steps of preparing a No. 2 photo-curing monomer and a No. 2 additive, mixing to obtain the isolation layer slurry, adding the photo-curing slurry into photo-curing 3D printing equipment, and performing photo-curing 3D printing according to the model of the frequency selective isolation layer to obtain the frequency selective isolation layer; The No. 2 photo-curing monomer consists of trimethylolpropane triacrylate and 1, 6-hexanediol diacrylate, wherein the trimethylolpropane triacrylate is 1, 6-hexanediol diacrylate=10-30:70-90; The No. 2 additive consists of a light absorber, a dispersing agent, a defoaming agent, a photoinitiator and a surfactant, wherein the light absorber, the dispersing agent, the defoaming agent, the photoinitiator and the surfactant are calculated according to mass ratio, the ratio of the surfactant to the dispersing agent is 0.1-3:0.1-5:0.1-0.5:0.1-0.2, the light absorber is Tinuvin-384-2, the dispersing agent is KMT-3331, the defoaming agent is SRE-2022A, the photoinitiator is 2,4, 6-trimethyl benzoyl ethyl phenylphosphonate, and the surfactant is BYK-333; Mixing the No. 2 photo-curing monomer and the No. 2 additive in a mixer in a vacuum environment, wherein the mixing speed is 400-800 rpm, and the mixing time is 2-30 min; When the photocuring 3D printing frequency selective isolation layer is used, the exposure energy is controlled to be 2.41-9.63 mJ/cm 2 , and the layer thickness is 50-100 mu m; And inserting a lead into the micro-channel in the frequency selective isolation layer and externally connecting the lead to the flexible circuit board, wherein the lead is connected with the electrode through conductive adhesive, and the epoxy resin adhesive fills the residual holes to fix the residual holes so as to form a vertical interconnection electrode structure.
9. The method for preparing the laminated multi-mode ultrasonic phased array probe according to claim 6, wherein the method comprises the following steps: Calculating the acoustic impedance of a second matching layer according to the acoustic impedance of a measured material, then preparing Al 2 O 3 ceramic powder and bisphenol A liquid epoxy resin according to the acoustic impedance of the second matching layer in a corresponding proportion, mixing with additive No. 3 to obtain matching layer slurry, and injecting the matching layer slurry into a mould to be solidified to obtain the second matching layer, wherein the mass fraction of the additive No. 3 in the matching layer slurry is 1-5 wt%; The particle size of the Al 2 O 3 ceramic powder is 100 nm-500 nm; the No. 3 additive consists of a dispersing agent and a curing agent, and consists of a silane coupling agent and a polyether amine curing agent, wherein the mass ratio of the silane coupling agent to the polyether amine curing agent is (60-85:15-40); Mixing Al 2 O 3 ceramic powder, an epoxy resin matrix and an additive in a mixer in a vacuum environment, wherein the mixing speed is 800-1500 rpm, and the mixing time is 5-30 min.
10. The method for preparing the laminated multi-mode ultrasonic phased array probe according to claim 6, wherein the method comprises the following steps: The preparation process of the backing layer comprises the steps of mixing tungsten powder, bisphenol A type liquid epoxy resin and No. 4 additive to obtain backing layer slurry, and injecting the backing layer slurry into a mould to be solidified to obtain the backing layer; the volume fraction of the tungsten powder in the slurry containing the tungsten powder is 65-90 wt.%, and the volume fraction of the epoxy resin is 5-34 wt.%; the particle size of the tungsten powder is 100 nm-500 nm; the No. 4 additive consists of a dispersing agent and a curing agent, and consists of a silane coupling agent and a polyether amine curing agent, wherein the mass ratio of the silane coupling agent to the polyether amine curing agent is (70-85:15-30); And mixing tungsten powder, an epoxy resin matrix and an additive in a mixer in a vacuum environment, wherein the mixing speed is 800-1200 rpm, and the mixing time is 5-20 min.

Description

Laminated multi-mode ultrasonic phased array probe and preparation method thereof Technical Field The invention belongs to the technical field of ultrasonic phased array probes, and particularly relates to a laminated multi-mode ultrasonic phased array probe and a preparation method thereof. Background In the field of ultrasound nondestructive testing, the functional integrity of the test probe needs to be manifested as multi-modal coverage of linear and nonlinear acoustic responses. In the linear detection mode, ultrasonic waves interact with macroscopic defects (such as macrocracks, holes and the like) in the material, and the positioning, quantitative and qualitative assessment of the defects are realized through the extraction and analysis of linear acoustic features such as reflected waves, scattered waves and the like. When the ultrasonic wave interacts with early damage mechanisms (such as dislocation, microcrack and the like) in the material, nonlinear distortion of the waveform is caused, and nonlinear components such as zero frequency, second order harmonic, higher order harmonic, mixing harmonic, subharmonic and the like are excited. These nonlinear acoustic indexes are extremely sensitive to early evolution of the microstructure of the material, and provide a new technical approach for life prediction and health state assessment of the component. Therefore, developing a multi-mode ultrasonic detection technology capable of combining high-efficiency linear defect detection and high-precision nonlinear early damage identification has become an important research direction in the field. However, the existing ultrasonic probe still has a series of technical bottlenecks to be solved in terms of realizing high-performance receiving and processing of broadband and multi-mode signals. The traditional single-frequency probe (such as a probe with a center frequency of 3 MHz) adopts a one-dimensional linear array element layout, has limited detection bandwidth, is difficult to simultaneously meet the high spatial resolution required by linear detection and the wide frequency spectrum coverage required by nonlinear detection, and particularly has obviously insufficient response capability on low-frequency components (such as zero-frequency signals and usually lower than 0.5 MHz) and high-frequency harmonic signals. In terms of acoustic matching design, conventional matching layers are generally optimized for only a single main frequency of the probe, resulting in serious impedance mismatch phenomena when the probe operates in a wide-band and multi-mode. The method not only greatly reduces the transmission efficiency and the receiving sensitivity of nonlinear harmonic signals, but also restricts the fidelity and the imaging resolution of the signals in a linear detection mode. In the structural layout of the probe, if a mode of horizontally staggered arrangement of high-frequency and low-frequency array elements is adopted, the overall size of the probe is increased, the focus of a sound field is enlarged, high-resolution imaging of fine defects is not facilitated, and if a compact structure of upper and lower lamination is adopted, a series of process problems of complicated interlayer electrical interconnection, concentrated stress of an isolation layer interface, poor contact reliability and the like are faced, so that independent and stable extraction of multi-mode signals is influenced. In addition, the existing manufacturing process is mostly dependent on multi-mode mechanical processing and manual assembly, is easy to introduce array element size errors and interlayer alignment errors, is difficult to realize the integrated forming of the acoustic functional layer with gradient impedance and complex topological structure, and finally restricts the performance consistency, sensitivity and long-term reliability of the probe in a broadband and multi-mode detection scene. In summary, there is a lack of an ultrasonic probe solution in the prior art that can be highly integrated in structure, realize broadband impedance matching acoustically, combine high-precision linear detection and high-sensitivity nonlinear early damage identification functionally, and have high precision and process controllability in manufacturing. Therefore, there is an urgent need to propose an innovative design and preparation method of a multi-mode ultrasonic probe to promote the development of the ultrasonic nondestructive testing technology in a more comprehensive, more precise and more stable direction. Disclosure of Invention In view of the shortcomings of the prior art, a first object of the present invention is to provide a stacked multi-mode ultrasound phased array probe. The second aim of the invention is to provide a preparation method of the laminated multi-mode ultrasonic phased array probe. In order to achieve the above purpose, the present invention adopts the following technical scheme: The invention relates to a la