A brazing fixture for high-temperature resistant piezoelectric material-based ultrasonic transducers

Abstract

This utility model discloses a brazing fixture for high-temperature resistant piezoelectric material-based ultrasonic transducers, specifically relating to the fields of high-temperature brazing and non-destructive testing. The fixture includes a fixing plate, a base, and a pressure block. This utility model provides a feasible brazing fixture for the development of high- and low-temperature ultrasonic transducers. The fixing plate uses a central groove to fix the piezoelectric material; the base serves as a matching layer tray; and the pressure block's gravity controls the thermal stress deformation caused by high-temperature brazing. This fixture can effectively achieve the welding of the high-temperature resistant piezoelectric material and the matching layer material, thus providing a key guarantee for the fabrication of ultrasonic transducers.

Description

Technical Field

[0001] This utility model relates to a brazing fixture for ultrasonic transducers based on high-temperature piezoelectric materials, belonging to the fields of high-temperature brazing and non-destructive testing technology. Background Technology

[0002] The stainless steel armor of fusion reactor superconducting magnets, operating in extremely low temperatures (4K) and strong magnetic environments for extended periods, will develop cracks and porosity defects, leading to conductor quenching failure and affecting the normal operation of the fusion reactor. Ultrasonic testing (UT) is a suitable monitoring technique, with the ultrasonic probe being its key component. Currently, domestic and international research on ultrasonic nondestructive testing largely focuses on the application of transducers in high-temperature environments, while literature on its application in extremely low-temperature environments is extremely scarce, particularly regarding the fabrication of related ultrasonic probes.

[0003] Currently, key components of commercial ultrasonic probes, such as piezoelectric crystals / matching layers and housings, are encapsulated using adhesive bonding. However, this method is highly susceptible to cracking and failure during low-temperature room-temperature cycling. Therefore, a low-temperature fatigue-resistant fabrication process needs to be designed. Research revealed that samples obtained through high-temperature brazing typically exhibit strong material bonding and are less prone to detachment in low-temperature environments. However, brazing requires high temperatures, necessitating the use of high-temperature piezoelectric materials with high Curie temperatures. High-temperature piezoelectric crystals are excellent piezoelectric materials, possessing high Curie temperatures, small piezoelectric temperature coefficients, high electromechanical coupling coefficients, low dielectric loss, stable physicochemical properties, good processing performance, and ease of fabrication into large-size, high-quality crystals. However, high-temperature piezoelectric materials are generally fragile and cannot be used alone to encapsulate probes; a matching layer as a protective film is essential. However, because the piezoelectric strain coefficient d33 of high-temperature piezoelectric materials is generally low, brazing ideal matching layers suitable for other piezoelectric materials, such as alumina, with high-temperature piezoelectric materials results in piezoelectric components with weak signals and large signal dead zones. Therefore, the thickness of the matching layer should be as thin as possible. However, thin-walled welding is prone to material deformation. Therefore, it is necessary to design an experimental fixture to fix the shape of the metal during welding, so as to reduce the deformation caused by thermal stress during welding and avoid the possibility of welding failure and cracking of piezoelectric material crystals due to deformation. Utility Model Content

[0004] This invention aims to solve the challenge of welding dissimilar materials, specifically high-temperature resistant piezoelectric materials and metal matching layers, with a focus on addressing the deformation of the metal matching layer during welding. This invention provides a brazing platform for ultrasonic probes suitable for use in high and low temperature environments. This design improves the high-temperature brazing method for fabricating piezoelectric components, providing the necessary conditions for the fabrication of commercially viable low-temperature ultrasonic probes.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a brazing fixture for a high-temperature resistant piezoelectric material-based ultrasonic transducer, comprising: a base, a fixing plate, and a pressing block; the base has a groove in which a matching layer, brazing filler metal, and piezoelectric material are placed; the fixing plate has a cylindrical boss with the same size as the matching layer; a through hole with the same size as the piezoelectric material is opened in the center of the cylindrical boss; the pressing block has a pressing block boss with the same size as the through hole; the pressing block boss is inserted into the through hole of the fixing plate to press the piezoelectric material, and the cylindrical boss presses the matching layer.

[0006] The beneficial effects of this utility model are:

[0007] 1. By utilizing the fixing effect of the tooling plate on the matching layer and the piezoelectric wafer, the deformation of the metal matching layer caused by high temperature during the welding process is reduced;

[0008] 2. The success rate of welding the matching layer and piezoelectric wafer is improved by utilizing the gravity of the tooling clamp. Attached Figure Description

[0009] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0010] Figure 1 This is a schematic diagram showing the overall stacking order of the modules in this utility model.

[0011] Figure 2 This is a schematic diagram of the chassis in this utility model.

[0012] Figure 3 This is a schematic diagram of the fixing plate in this utility model.

[0013] Figure 4 This is a schematic diagram of the pressure block in this utility model.

[0014] Among them, 1-pressing block, 2-fixing plate, 3-base plate, 4-piezoelectric material, 5-brazing filler metal, 6-matching layer, 7-base plate surface, 8-groove, 9-cylindrical boss surface, 10-fixing plate through hole, 11-cylindrical boss, 12-pressing block upper surface, 13-pressing block boss. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, the present utility model adopts the following technical solution.

[0016] like Figure 1 As shown, this utility model provides a brazing fixture for a high-temperature resistant piezoelectric material-based ultrasonic transducer, comprising: a base plate 3, a fixing plate 2, and a pressure block 1;

[0017] The chassis 3 is provided with a groove 8, which can be used to place the matching layer 6, the brazing filler metal 5 and the piezoelectric material 4 in sequence. The three materials are stacked in the above order.

[0018] like Figure 2 As shown, the chassis 3 has threaded holes arranged around its perimeter and at its center. The threaded holes around the perimeter are used to connect with the fixing plate 2, while the threaded hole at the center is used to disassemble the welded parts after welding.

[0019] The dimensions of the central groove in chassis 3 are the same as those of the matching layer 6 material, with an upper tolerance of 0.02-0.1mm and a lower tolerance of 0mm. The depth is consistent with the thickness of the matching layer 6.

[0020] like Figure 3 As shown, fixing plate 2 has through holes 10 arranged around its perimeter. The positions of the through holes 10 are the same as the positions of the threaded holes around the perimeter of the chassis 3 to facilitate screw fixing. The center of fixing plate 2 is a cylindrical boss 11, which has a cylindrical boss surface 9. The outer diameter of the cylindrical boss 11 is the same as the size of the mating layer 6, with an upper tolerance of 0mm and a lower tolerance of 0.02-0.1mm. The height of the cylindrical boss 11 is 1-5mm greater than the thickness of the mating layer. The fixing plate boss 11 can fix the brazing filler metal 5 around the piezoelectric material 4 and the mating layer 6, corresponding to… Figure 1 The portion of the upper surface of the brazing filler metal 5 that is not pressed down by the piezoelectric material 4.

[0021] The cylindrical boss 11 of the fixing plate 2 has a through hole in the center. The opening size of the through hole is the same as that of the piezoelectric material 4, with an upper tolerance of 0.02-0.1mm and a lower tolerance of 0mm.

[0022] like Figure 4As shown, the pressure block 1 has a pressure block boss 13 at its center and an upper surface 12. The dimensions of the pressure block boss 13 are the same as those of the piezoelectric material 4, with an upper tolerance of 0mm and a lower tolerance of 0.02-0.1mm. The height of the pressure block boss 13 is 3-5mm greater than the thickness of the fixing plate 2. The pressure block 1 is placed into the through hole of the fixing plate, and its bottom end 13 presses against the upper surface of the piezoelectric material 4 in the groove of the base plate, using the counterweight of the pressure block 1 to assist welding.

[0023] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A high temperature piezoelectric material based ultrasonic transducer brazing fixture, characterized by, include: The chassis comprises a base plate, a mounting plate, and a pressure block. The base plate has a groove in which a matching layer, brazing filler metal, and piezoelectric material are placed. The mounting plate has a cylindrical boss with the same dimensions as the matching layer. A through hole with the same dimensions as the piezoelectric material is opened in the center of the cylindrical boss. The pressure block has a pressure block boss with the same dimensions as the through hole. The pressure block boss is inserted into the through hole of the mounting plate to press the piezoelectric material, and the cylindrical boss presses the matching layer.

2. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 1, wherein, The three materials—supporting matching layer, solder, and high-temperature resistant piezoelectric material—are stacked in sequence.

3. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 1, wherein, The chassis has threaded holes around its perimeter and at its center. The threaded holes around the perimeter are used to connect to the fixed plate, while the threaded hole at the center is used to disassemble the welded parts after welding.

4. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 1, wherein, The chassis has a groove in the center, the size of which is the same as the size of the matching layer, with an upper tolerance of 0.02-0.1mm, a lower tolerance of 0mm, and a depth consistent with the thickness of the matching layer.

5. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 1, wherein, The fixing plate has through holes around its perimeter, and the positions of the through holes are the same as the positions of the threaded holes around the chassis. The center of the fixing plate is a cylindrical boss with the outer diameter of the cylinder being the same as the size of the matching layer. The upper tolerance is 0mm and the lower tolerance is 0.02-0.1mm.

6. The brazing fixture for a high-temperature resistant piezoelectric material-based ultrasonic transducer according to claim 1, characterized in that, The fixed plate has a through hole at the center of the protrusion. The hole size is the same as that of the piezoelectric material, with an upper tolerance of 0.02-0.1 mm and a lower tolerance of 0 mm.

7. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 1, wherein, The size of the boss of the pressure block is the same as the size of the matching layer used, with an upper tolerance of 0mm and a lower tolerance of 0.02-0.1mm.

8. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 7, wherein, The height of the pressure block boss is 3-5mm greater than the thickness of the fixing plate.

9. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 2, wherein, The thickness of the matching layer is 0.1-0.2 mm.

10. The high temperature piezoelectric material based ultrasonic transducer brazing tooling of claim 5, wherein, The height of the cylindrical boss is 1-5mm greater than the thickness of the matching layer.

Images