Ultrasonic inspection device, ultrasonic inspection method, and contact member

Abstract

To provide a sonic wave inspection device capable of bringing a contact medium into close contact with an object to be inspected during inspection, easily moving the contact medium, and suppressing reduction in an S / N ratio.SOLUTION: A sonic wave inspection device 1 comprises: a transducer 3 configured to perform at least one of transmitting and receiving sonic waves; a sonic wave probe 2 having a sonic wave functional surface 2a constituting at least one of a transmission surface and a reception surface for sonic waves; a contact medium 11 that has a first surface in contact with the sonic wave functional surface 2a of the sonic wave probe 2 directly or via an intermediate member and a second surface opposite to the first surface, and that contains an elastomer; a contact member 9 comprising a sheet-like member 11 laminated with the contact medium so as to be in contact with the second surface, and containing a polymer; and a load mechanism that applies a load to the contact member 9.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to an acoustic wave inspection apparatus, an acoustic wave inspection method, and a contact member.

Background Art

[0002] An acoustic wave inspection apparatus that uses the propagation of acoustic waves such as ultrasonic waves and elastic waves is used for inspecting various members, devices, infrastructures, etc. In addition, ultrasonic inspection apparatuses are also used for medical diagnosis and the like. When installing an acoustic wave inspection probe such as an ultrasonic probe, an AE (Acoustic Emission) sensor, or an acoustic wave transmitter / receiver, which is a receiver, transmitter, or transmitter / receiver for acoustic wave inspection used in such inspection apparatuses, on a test object, in order to efficiently perform acoustic wave propagation between the test object and the probe, a liquid or viscous contact medium such as glycerin or petrolatum is interposed between the acoustic wave functional surface that constitutes at least one of the acoustic wave transmission surface and the reception surface of the probe and the test object.

[0003] The above-described contact medium is important for efficiently transmitting acoustic waves such as ultrasonic waves from the probe to the test object or from the test object to the probe and improving the test accuracy. However, the process of applying or removing a liquid or viscous contact medium is complicated. For this reason, it is a factor that increases the time and man-hours of the inspection. In addition, depending on the test object to be inspected, it may be contaminated with the contact medium, and in that case, the inspection itself cannot be carried out.

[0004] Solid contact media have also been proposed, but the propagation of ultrasonic waves is significantly inferior compared to the case of using a liquid contact medium. This is presumably because air with a significantly different acoustic impedance intervenes between the contact medium of the probe and the object to be inspected. In order to avoid air intervening between the installation surface of the contact medium for acoustic wave inspection and the object to be inspected, an adhesive solid contact medium has also been proposed. However, when using a conventional adhesive solid contact medium, the installation surface of the contact medium for acoustic wave inspection adheres tightly to the object to be inspected, and the contact medium for acoustic wave inspection cannot be slid. Therefore, even when moving the installation position by a minute distance, it is necessary to peel off the probe together with the contact medium from the object to be inspected, making the inspection process complicated.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the present invention is to provide an acoustic wave inspection device, an acoustic wave inspection method, and a contact member that can bring the contact medium into close contact with the object to be inspected during inspection, can easily move the contact medium, and can suppress a decrease in the S / N ratio.

Means for Solving the Problems

[0007] The acoustic wave inspection device according to the embodiment includes a vibrator configured to perform at least one of transmission and reception of acoustic waves, an acoustic wave probe having an acoustic wave functional surface that constitutes at least one of a transmission surface and a reception surface of the acoustic waves, a first surface that is in direct contact with or in contact with the acoustic wave functional surface of the acoustic wave probe via an intermediate member, a second surface opposite to the first surface, a contact medium containing an elastomer, and the second surface Fullystacked so as to be in contact with the contact medium, having a uniform thickness, a contact member including a sheet-like member containing a polymer, and a load mechanism for applying a load to the contact member and the polymer includes at least one selected from the group consisting of polyester, polyethylene, polypropylene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyphenylene sulfide, and polyvinylidene chloride, and the sheet-like member has a thickness of 1 / 250 or more and 1 / 2 or less of the wavelength λ of the sound wave transmitted from the vibrator and propagating through the sheet-like member, or a thickness of 10 μm or more and 1 mm or less.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0009] Hereinafter, an ultrasonic inspection apparatus, an ultrasonic inspection method, and a contact member for an ultrasonic inspection apparatus according to embodiments will be described with reference to the drawings. In each embodiment, substantially the same constituent parts are denoted by the same reference numerals, and the description thereof may be partially omitted. The drawings are schematic, and the relationship between the thickness and the planar dimensions of each part, the ratio of the thicknesses of each part, etc. may be different from the actual ones. The terms indicating the vertical direction in the description indicate the relative direction when the inspection surface of the object to be inspected is upward, and may be different from the actual direction based on the direction of gravitational acceleration.

[0010] FIG. 1 is a diagram showing an acoustic inspection apparatus according to an embodiment. The acoustic inspection apparatus 1 shown in FIG. 1 has a vertical acoustic probe 2. The acoustic inspection apparatus 1 has, for example, a pulse-echo type acoustic probe 2, and performs non-destructive inspection such as flaw detection by measuring acoustic waves (reflected waves) returning from an inspection object such as a flaw in a test body. Alternatively, the acoustic probe 2 performs non-destructive inspection such as flaw detection by measuring acoustic waves generated by the inspection object. The acoustic probe 2 has at least one of the functions of transmitting and receiving acoustic waves, and specific examples include an ultrasonic transceiver (ultrasonic transducer) and an acoustic wave receiver. A representative example of the ultrasonic transceiver is an ultrasonic probe. A representative example of the acoustic wave receiver is an AE sensor. The acoustic probe 2 may be an acoustic wave transmitter.

[0011] The acoustic waves described herein are a general term for all elastic vibration waves that propagate through an elastic body, regardless of whether the elastic body is a gas, a liquid, or a solid, and include not only acoustic waves in the audible frequency range but also ultrasonic waves having a frequency higher than the audible frequency range and low-frequency acoustic waves having a frequency lower than the audible frequency range. The frequency of the acoustic waves is not particularly limited and includes those from high frequency to low frequency. In the acoustic inspection apparatus 1 according to the embodiment, the acoustic probe 2 has an acoustic wave transmission surface, a reception surface, a transmission surface, and the like. Here, a surface that constitutes at least one of the acoustic wave transmission surface and the reception surface of the acoustic probe 2 is referred to as an acoustic wave functional surface. The acoustic probe 2 is provided with such an acoustic wave functional surface 2a.

[0012] In the acoustic wave inspection apparatus 1 shown in FIG. 1, the acoustic wave probe 2 is, for example, an ultrasonic probe as an ultrasonic transceiver. As shown in FIG. 2, the ultrasonic probe 2 includes an ultrasonic transmitting and receiving element 5 having a vibrator (piezoelectric body) 3 for ultrasonic flaw detection and electrodes 4 provided on both the upper and lower surfaces of the vibrator 3. The ultrasonic transmitting and receiving element 5 is disposed on a receiving plate 6 and is accommodated in a case 7 in this state. The electrode 4 of the ultrasonic transmitting and receiving element 5 is electrically connected to a connector 8 provided on the case 7. For the vibrator 3, the ultrasonic transmitting and receiving element 5, the receiving plate 6, etc., the constituent materials, structures, etc. used in known ultrasonic probes can be applied, and there is no particular limitation. When the acoustic wave probe 2 is an acoustic wave receiver such as an AE sensor, a configuration similar to that of the ultrasonic probe is applied except that an acoustic wave receiving element having a vibrator (piezoelectric body) 3 for AE reception is used. In that case, for the vibrator 3 for AE reception, the acoustic wave receiving element, the receiving plate 6, etc., the constituent materials, structures, etc. used in known AE sensors can be applied.

[0013] When an ultrasonic probe is applied as the acoustic wave probe 2, by applying a voltage from the electrode 4 to the vibrator 3, ultrasonic waves are transmitted through the receiving plate 6 and at the same time, the reflected waves of the ultrasonic waves are received through the receiving plate 6. In the ultrasonic probe, the surface 6b on the side opposite to the surface 6a of the receiving plate 6 in contact with the ultrasonic transmitting and receiving element 5 becomes the transmitting surface and receiving surface (transmitting and receiving surface) of the ultrasonic waves. When an AE sensor is applied as the acoustic wave probe 2, the vibrator 3 receives the acoustic waves (elastic waves) due to AE in the object to be inspected through the receiving plate 6. In the AE sensor, the surface 6b on the side opposite to the surface 6a of the receiving plate 6 in contact with the acoustic wave receiving element becomes the receiving surface of the acoustic waves. In the acoustic wave probe 2, the surface 6b on the side opposite to the surface 6a of the receiving plate 6 in contact with the acoustic wave element 5 (hereinafter sometimes collectively referred to as the acoustic wave element) where the ultrasonic transmitting and receiving element or the acoustic wave receiving element is disposed becomes an acoustic wave functional surface 2a that constitutes (functions as at least one of) at least one of the transmitting surface and receiving surface of the acoustic waves.

[0014] On the acoustic functional surface 2a of the acoustic probe 2, a contact member 9 that functions as an acoustic propagation unit is provided. As shown enlarged in Fig. 3, the contact member 9 includes a contact medium 10 containing an elastomer and a sheet-like member 11 containing a polymer sheet. Here, a structure in which the sheet-like member 11 containing a polymer sheet is laminated on the contact medium 10 containing an elastomer is shown, but the sheet-like member 11 containing a polymer sheet is not limited to this, and it may have a sheet-like shape. The sheet-like member 11 may be a sheet-like member containing a polymer, for example, it may be a polymer layer. The constituent material of the polymer sheet may be, in addition to those separated from the elastomer, for example, a polymer layer formed by surface-treating the elastomer by non-sticking treatment (non-sticking coating) such as sliding coating. The polymer layer formed by non-sticking treatment has a thickness of, for example, 30 μm or more. The sheet-like member 11 may be formed and configured by any method.

[0015] The contact medium 10 has a first surface 10a that contacts the acoustic functional surface 2a of the acoustic probe 2 directly or via an intermediate member, and a second surface 10b on the side opposite to the first surface 10a. The first surface 10a of the contact medium 10 may be adhered to the acoustic functional surface 2a of the acoustic probe 2 directly or via an intermediate member by an adhesive (not shown). Examples of the intermediate member include shoes and bonding layers made of polymer materials. The sheet-like member 11 has a third surface 11a laminated with the contact medium 10 so as to contact the second surface 10b, and a fourth surface 11b on the side opposite to the third surface 11a. The third surface 11a of the sheet-like member 11 may be adhered to the second surface 10b of the contact medium 10 by an adhesive (not shown). The fourth surface 11b of the sheet-like member 11 constitutes a contact surface with the subject (object to be processed) X.

[0016] The ultrasonic probe 2 and the contact member 9 may be joined by a joining layer 13 disposed between the ultrasonic functional surface 2a and the first surface 10a, for example, as shown in FIG. 4. The joining layer 13 has a configuration in which, for example, a first adhesive layer 14 having reversibility, a polymer layer 15, and a second adhesive layer 16 are arranged in this order. Although each of these layers 14, 15, and 16 will be described in detail later, by using the first adhesive layer (reversible adhesive layer) 14 having reversibility, the attachment and detachment of the contact member 9 with respect to the ultrasonic probe 2 can be easily performed. For example, the subject X is not limited to a bulk solid, and may be a powder aggregate or a compacted powder. In such an inspection, since the powder as the subject X adheres to the contact member 9, it may be necessary to replace the contact member 9. By easily detaching the contact member 9 from the ultrasonic probe 2, it becomes possible to improve the inspection efficiency of the subject X such as a powder aggregate.

[0017] The ultrasonic inspection device 1 is arranged such that the fourth surface 11b of the sheet-like member 11 contacts the subject X. The ultrasonic inspection device 1 has a load application jig 12 provided on the ultrasonic probe 2. In the ultrasonic inspection device 1, first, a load is applied to the ultrasonic probe 2 via the load application jig 12, and further, a load is applied to the contact member 9 via the ultrasonic probe 2. As will be described later, the contact medium 10 contacts the subject X via the sheet-like member 11 due to the load applied to the contact member 9. Therefore, ultrasonic waves can be efficiently propagated between the contact medium 10 and the subject X via the sheet-like member 11.

[0018] Furthermore, by means of a sheet-like member 11 including an ultrathin non-sticky polymer sheet provided as a dry contact medium on the surface 10b of the contact medium 10, it is possible to move the ultrasonic inspection device 1 over the test object X in a sliding state as described later without removing the load applied by the load application jig 12. As a result, the ultrasonic inspection device 1 can be easily moved to the next position of the test object X without removing the load applied by the load application jig 12. The application of a load to the contact medium 10 can be carried out by various mechanisms that apply a force to the contact medium 10. For example, a load can be applied to the contact medium 10 by mechanisms such as an electric actuator using a stepping motor or an AC servo motor, or an actuator using hydraulic pressure or pneumatic pressure. The actuator etc. and the load application jig 12 constitute a load mechanism.

[0019] In a state where a load is applied to the contact member 9 by the load application jig 12, due to at least the deformation characteristics of the contact medium 10 containing an elastomer, that is, an ultra-low elastic modulus, reversible large deformation, viscoelasticity, etc., the contact medium 10 deforms so as to follow the unevenness etc. on the surface of the test object X. Due to such deformation of the contact medium 10 caused by the applied load, a state in which the contact medium 10 is in close contact with the test object X via the sheet-like member 11 is obtained. The sticky elastomer can propagate sound waves such as ultrasonic waves well, similar to a liquid contact medium. Therefore, by bringing the contact medium 10 into a state of being in close contact with the test object X via the sheet-like member 11, sound waves can be efficiently propagated between the contact medium 10 and the test object X via the sheet-like member 11 when a load is applied. The sheet-like member 11 including an ultrathin non-sticky polymer sheet inhibits the adhesion state with the test object X without impairing the propagation of sound waves such as ultrasonic waves, as described later. These make it possible to achieve both an improvement in the non-destructive inspection accuracy of the test object X by the ultrasonic inspection device 1 and the mobility of the ultrasonic inspection device 1 on the test object X.

[0020] When measuring the frictional force of an elastomer, it is observed that the frictional force is overwhelmingly large compared to other materials, and in some cases, friction exceeding 1 may be observed. The origin of this large frictional force is due to the adhesion of the elastomer to the test object X, and it is a phenomenon observed because the contact area becomes extremely large due to deformation. Even when trying to bring hard materials such as metals into contact with each other, only the roughness at a very small part of the contact surface, specifically only the tips of the micro-protrusions, come into contact. However, when the elastic modulus is low like that of an elastomer, the deformability is large even with the same load, so the adhesive force increases. Thus, since the elastomer has a large substantial (microscopic) contact area with the test object X through the sheet-like member 11, ultrasonic waves can pass through well. However, the easier it is for ultrasonic waves to pass through, the larger the frictional force and the more difficult it is to peel off. Therefore, in the contact member 9, as shown in FIGS. 3 and 4, a sheet-like member 11 is provided on the surface 10b of the contact medium 10, thereby facilitating movement during loading.

[0021] The elastomers used as the contact medium 10 include thermosetting elastomers and thermoplastic elastomers, and both can be used in the acoustic inspection device 1 of the embodiment. A thermoplastic elastomer is a copolymer of two or more types of polymers with different temperature dependences of the elastic modulus. The elastomer used in the acoustic inspection device 1 of the embodiment has a predetermined viscoelasticity and can closely adhere along the surface shape of the object. Therefore, it does not contaminate the surroundings compared to other contact media such as water and oils, and since it is a solid, it is easy to remove and can also be reused. In order to eliminate the air layer intervening between the contact member 9 and the test object X by pressing the contact medium 10 against the test object X, the Young's modulus (elastic constant) of the elastomer is preferably 0.1 MPa or more and 10 MPa or less.

[0022] When the Young's modulus of the elastomer constituting the contact medium 10 exceeds 10 MPa, the followability to the surface of the test object X and the ability to eliminate the air layer deteriorate. When the Young's modulus of the elastomer is less than 0.1 MPa, the shape maintaining ability and the like when a load is applied to the contact medium 10 deteriorate. It is desirable that the yield stress, which is the stress at which the plasticity of the material starts, be large, more preferably 2 MPa or more, and desirably 20 MPa or more. It is also preferable that the tensile strength of the elastomer be large, preferably 2 MPa or more. The thickness of the elastomer constituting the contact medium 10 is preferably 10 mm or less. Although the suitable thickness varies depending on the acoustic impedance and Young's modulus of the elastomer constituting the contact medium 10, when it has a thickness of about 0.5 mm or more and 2 mm or less, the propagation performance of ultrasonic waves and the like can be enhanced.

[0023] Examples of the thermoplastic elastomer constituting the contact medium 10 include polystyrene-based thermoplastic elastomers (SBC, TPS), polyolefin-based thermoplastic elastomers (TPO), vinyl chloride-based thermoplastic elastomers (TPVC), polyurethane-based thermoplastic elastomers (TPU), polyester-based thermoplastic elastomers (TPEE, TPC), polyamide-based thermoplastic elastomers, and the like. Examples of the thermosetting elastomer include styrene-butadiene rubber (SBR), isoprene rubber (IR), butadiene rubber (BR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), which are classified as diene rubbers, and butyl rubber such as isobutylene-isoprene rubber (IIR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), urethane rubber (U), silicone rubber, fluororubber (FKM), and the like, which are classified as non-diene rubbers. Examples of other rubbers include chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), acrylic rubber (ACM), polysulfide rubber (T), epichlorohydrin rubber (CO, ECO), and the like. Since each material has characteristics such as heat resistance, abrasion resistance, oil resistance, and chemical resistance, it is preferably selected as appropriate according to the inspection object. Depending on the application, a plurality of elastomers may be mixed and used. Additives having a size that does not interfere with the transmission of sound waves, that is, generally additives having a diameter of 200 μm or less may be mixed.

[0024] The elastomer constituting the contact medium 10 more preferably contains at least one selected from the group consisting of polyester-based thermoplastic elastomers, styrene-butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, isobutylene-isoprene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, silicone rubber, fluororubber, chlorosulfonated polyethylene, acrylic rubber, and epichlorohydrin rubber, which are excellent in heat resistance.

[0025] For the polymer constituting the sheet-like member 11, a material having a Young's modulus greater than that of the elastomer constituting the contact medium 10 is used. For example, polyester, polyolefins such as polyethylene and polypropylene, fluororesins such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride, polyphenylene sulfide, and a sheet-like member made of polyvinylidene chloride are used. By laminating such a non-adhesive polymer sheet on the surface of the contact medium 10 as the sheet-like member 11, it is possible to move the ultrasonic inspection device 1 smoothly on the test object X without removing the load on the contact medium 10. The non-adhesiveness described here means that when the medium is brought into contact with the inspection object, if the medium is moved vertically with respect to the inspection object, it is easily peeled off from the inspection object. The Young's modulus of the polymer is more preferably 100 MPa or more for enhancing the slipperiness. The Young's modulus of the polymer is preferably 2000 MPa or less for enhancing the followability to the surface unevenness of the test object X and the like.

[0026] Fig. 5 shows the results of measuring the amplitude of the reflected wave when ultrasonic waves are irradiated from the ultrasonic probe 2 to the test object X in the case where the contact medium 10 containing an elastomer and the sheet-like member 11 containing a polymer sheet are provided on the ultrasonic functional surface 2a of the ultrasonic probe 2, and in the case where only the contact medium 10 containing an elastomer is provided on the ultrasonic functional surface 2a of the ultrasonic probe 2. The elastomer member and the polymer sheet used here will be described in detail in Example 1 below. As shown in Fig. 5, by laminating and using the elastomer and the polymer sheet, although the amplitude of the reflected wave slightly decreases compared to the case of using only the elastomer, it can be seen that a practically usable reflected wave amplitude can be obtained as the ultrasonic inspection device 1 in a state where a certain load is applied.

[0027] The polymer sheet constituting the sheet-like member 11 preferably has a thickness of 1 / 250 or more and 1 / 2 or less of the wavelength λ of the sound wave propagating through the sheet. By using a polymer sheet having such a thickness, ultrasonic waves and the like can be favorably propagated between the ultrasonic probe 2 and the subject X through the contact member 9 having the contact medium 10 and the sheet-like member 11. Fig. 6 shows the simulation results of the reflection signal when the ratio (d / λ) of the thickness d of the polymer sheet to the wavelength λ in the polymer sheet at 2.25 MHz is changed by 1 / 8 from 0 to 1. As shown in Fig. 6, by the polymer sheet having a thickness d that satisfies a d / λ ratio of 1 / 2 or less, the detection performance by ultrasonic waves and the like can be enhanced.

[0028] Although there are differences depending on the constituent material of the polymer sheet, the speed of sound in the polymer sheet is generally around 1800 m / s to 2500 m / s. In non-destructive inspection, sound waves with a frequency of 1 MHz or more are mainly used. When the frequency is 1 MHz, if the speed of sound is 2500 m / s, the wavelength λ in the polymer sheet is 2.5 mm, so 10 μm is about 1 / 250 of the wavelength. In practical use, if the thickness of the polymer sheet is less than 10 μm, depending on the surface state of the subject X, there is a risk of being easily damaged by minute irregularities on the surface of the subject X. The specific thickness of the polymer sheet is preferably 10 μm or more and 1 mm or less. Furthermore, by using a polymer sheet having such a thickness, after following the surface irregularities of the subject X during inspection, the sound wave inspection device 1 can be moved on the subject X in a state where the load on the contact medium 10 is not removed and the device is slid.

[0029] As described above, in the acoustic wave inspection apparatus 1 of the embodiment, a contact medium 10 containing an elastomer and a sheet-like member 11 containing a polymer sheet are provided as a contact member 9 on the acoustic wave functional surface 2a of the acoustic wave probe 2. Among the contact members 9, when a load is applied, the contact medium 10 containing an elastomer comes into close contact with the object to be inspected X, so that acoustic waves such as ultrasonic waves can be favorably propagated between the acoustic wave probe 2 and the object to be inspected X. Therefore, it becomes possible to improve the accuracy of the non-destructive inspection by the acoustic wave inspection apparatus 1. Further, the polymer sheet provided as the sheet-like member 11 on the surface of the contact medium 10 does not impair the propagation property of ultrasonic waves and the like, so that the non-destructive inspection accuracy is not impaired. Moreover, by using the polymer sheet as a dry contact medium for the object to be inspected X, it is possible to move the acoustic wave inspection apparatus 1 on the object to be inspected X in a sliding state without removing the load on the contact medium 10. Thereby, when moving the acoustic wave inspection apparatus 1, the time and man-hours required for removing the load can be reduced. Therefore, it becomes possible to improve the efficiency of the inspection process by the acoustic wave inspection apparatus 1.

[0030] In the bonding layer shown in FIG. 4, the first adhesive layer (reversible adhesive layer) 14 having reversibility causes a change in adhesive force due to a change in stimulus / environment by containing, for example, any one of a temperature-sensitive adhesive, a photoirradiation curable agent, a heat-expandable agent, a thermal expansion agent, and a photo-structural change agent. By providing such a reversible adhesive layer 14, the contact member 9 can be quickly removed from the acoustic wave probe 2 by using photoirradiation, temperature change, or the like when desired. The polymer layer 15 and the second adhesive layer 16 are provided between the reversible adhesive layer 14 and the contact medium 10, and may be required when integrating these two, and are provided as needed.

[0031] The reversible adhesive layer 14 preferably has a thickness of, for example, 10 μm or more and 100 μm or less. Examples of the reversible adhesive layer include a temperature-sensitive adhesive layer whose adhesiveness decreases at a low temperature. The temperature-sensitive adhesive layer contains a side-chain crystalline polymer as a main component, and when cooled to a temperature below the melting point of the side-chain crystalline polymer, the side-chain crystalline polymer crystallizes, resulting in a decrease in adhesive strength. As the side-chain crystalline polymer, for example, various side-chain crystalline methacrylic resins are used.

[0032] Another example of the reversible adhesive layer 14 is a temperature-sensitive adhesive layer whose adhesiveness decreases at a high temperature. As the temperature-sensitive adhesive layer, those containing a side-chain crystalline polymer and a foaming agent are known. The temperature-sensitive adhesive layer contains a side-chain crystalline polymer as a main component and contains the foaming agent in a proportion of 1 to 60 parts by weight based on 100 parts by weight of the side-chain crystalline polymer. Thereby, when the temperature-sensitive adhesive layer is heated to a temperature equal to or higher than the foaming temperature of the foaming agent, the side-chain crystalline polymer becomes fluid, the cohesive force of the adhesive layer decreases, and the foaming agent foams and swells, so that the contact member 9 can be easily removed from the ultrasonic probe 2.

[0033] Examples of the side-chain crystalline polymer include methacrylate-based resins. As the foaming agent, a chemical foaming agent or a physical foaming agent can be used. Chemical foaming agents include thermally decomposable and reactive organic foaming agents and inorganic foaming agents. Examples of the thermally decomposable organic foaming agent include various azo compounds, nitroso compounds, hydrazine derivatives, etc. Examples of the reactive organic foaming agent include isocyanate compounds, etc. Examples of the thermally decomposable inorganic foaming agent include bicarbonates, carbonates, etc. As other foaming agents, commercially available microencapsulated thermally expandable microparticles can be used. The average particle size of the foaming agent is preferably 5 to 50 μm.

[0034] As yet another example of the reversible adhesive layer 14, a photo-curable release layer can be mentioned. The photo-curable release layer contains, for example, 100 parts by weight of a methacrylic polymer which is a side-chain crystalline block copolymer, and 0.1 to 2 parts by weight of a photo-polymerization initiator. Further, one type of the photo-polymerization initiator may be used alone, or two or more types of photo-polymerization initiators may be used in combination.

[0035] The polymer layer 15 is preferably in the form of a film. The form of a film is not limited to only a film, and is a concept including a film or a sheet or the like as long as the effects of the embodiment are not impaired. Examples of the constituent material of the polymer layer 15 include synthetic resins such as polyethylene, polyethylene terephthalate, polypropylene, polyester, polyamide, polyimide, polycarbonate, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene polypropylene copolymer, and polyvinyl chloride. The polymer layer 15 may be either a single layer or a multi-layer, and its thickness is preferably 5 to 250 μm. The polymer layer 15 may be subjected to a surface treatment such as corona discharge treatment, plasma treatment, blasting treatment, chemical etching treatment, primer treatment, etc. in order to enhance the adhesion to the second adhesive layer 16.

[0036] The second adhesive layer 16 is provided to adhere the polymer layer 15 and the contact medium 10 containing an elastomer. As the second adhesive layer 16, for example, a rubber-based solvent-type adhesive can be used. As the rubber-based solvent-type adhesive, an SBS (styrene-butadiene-styrene) resin-based adhesive or a chloroprene rubber-based adhesive can be used. At the time of adhesion, a surface treatment such as corona discharge treatment, plasma treatment, blasting treatment, chemical etching treatment, primer treatment, etc. can be performed.

Examples

[0037] Hereinafter, examples and their evaluation results will be described.

[0038] (Example 1, Comparative Example 1) First, an ultrasonic probe with a frequency of 2.25 MHz was prepared. As the elastomer member, a styrene-butadiene elastomer (containing process oil, hardness JIS type E is 4, and the sound velocity under experimental conditions is 1350 m / s) was prepared. The thickness of the elastomer member is 1 mm. As the polymer sheet A, a polyvinylidene chloride sheet (Young's modulus: 350 - 560 MPa, sound velocity under experimental conditions: 1960 m / s) was prepared. The thickness of the polymer sheet A is 10 μm, which corresponds to 1 / 100 of the wavelength within the sheet.

[0039] The polymer sheet A was adhered to the elastomer member with an ultrathin SBS adhesive. On the surface of the polymer sheet A opposite to the adhered surface, a polymer layer (PET sheet) with a thickness of 20 μm was adhered with an ultrathin SBS adhesive. The PET sheet was laminated on the ultrasonic transmitting and receiving surface of the ultrasonic probe via a reversible adhesive layer. In this way, the reversible adhesive layer, polymer layer, adhesive layer, elastomer member, and polymer sheet A were laminated on the ultrasonic probe in sequence. The reversible adhesive layer used at this time is a temperature-sensitive adhesive layer whose adhesiveness decreases at high temperatures. A layer with a thickness of 30 μm was used, which was a mixture of 100 parts by weight of a polymethacrylate-based resin and 10 parts by weight of microencapsulated thermally expandable microparticles (manufactured by Nippon Fillite Co., Ltd., Expancel (registered trademark)).

[0040] First, a shear tensile test was carried out to examine whether the probe can be moved without applying a load greater than its own weight. A load cell was connected to the above ultrasonic probe, and it was placed on a stainless steel plate with a surface roughness Rz of 32 μm. The stainless steel plate was moved at a low speed to measure the static friction coefficient. As Comparative Example 1, the measurement was also carried out for only the elastomer member without the polymer sheet attached. As a result, it was found that when the polymer sheet was not provided, the static friction coefficient was extremely large and it was difficult to move the ultrasonic probe, but when the polymer sheet was installed, the static friction coefficient uniformly became small and it was possible to move it.

[0041] Next, an ultrasonic flaw detection test was carried out. A carbon steel block with a length of 300 mm was prepared. The surface roughness Rz of the surface where ultrasonic waves were projected was set to 18 μm, and the surface roughness Rz of the surface where ultrasonic waves bounced back was set to 1.6 μm. A load was applied to a 2.25 MHz vertical ultrasonic probe and pressed against the carbon steel block for the flaw detection test. As Comparative Example 1, a flaw detection test was conducted on an ultrasonic probe equipped with only an elastomer member. Fig. 5 shows an example of the relationship between the load and the reflected wave amplitude. Under these experimental conditions, in the case of only the elastomer, a reflected wave amplitude was obtained even under no load (0 MPa), but when Polymer Sheet A was present, by setting the load to 0.015 MPa or more, an amplitude approximately 1 / 10 of the signal of only the elastomer member was obtained. At this level, flaw detection is sufficiently possible by adjusting the gain of the flaw detection test device.

[0042] Fig. 7 shows the signal waveform by the ultrasonic probe of Example 1. As shown in the portion surrounded by the dotted ellipse in Fig. 7, a clear signal waveform was obtained, indicating that the performance of the ultrasonic probe was demonstrated. Furthermore, when an attempt was made to move on the carbon steel block while applying a load by the actuator, it was confirmed that it was possible to move easily while maintaining the amplitude. After the test, when the contact member was heated with a dryer, when the temperature reached 120 °C, the contact member peeled off from the ultrasonic probe. The contact member could be easily replaced.

[0043] (Reference Example 1) A polyimide sheet (Young's modulus: 2100 MPa, sound velocity under experimental conditions: 2450 m / s) was prepared as Polymer Sheet B. The thickness of Polymer Sheet B was 12.5 μm, which corresponds to 1 / 100 of the wavelength in the sheet. The same ultrasonic probe, elastomer member, and Polymer Sheet B as in Example 1 were used, and the elastomer member and Polymer Sheet B were laminated on the ultrasonic probe in the same manner as in Example 1. In the same shear tensile test as in Example 1, it was found that the static friction coefficient was uniformly small for Polymer Sheet B as well, and it was possible to move it.

[0044] Next, an ultrasonic flaw detection test was carried out under the same conditions as in Example 1. The flaw detection results when using Polymer Sheet B are shown in FIG. 8. As shown in FIG. 7, a reflection signal was clearly observed in Polymer Sheet A, whereas in Polymer Sheet B, multiple reflections occurred between the elastomer member and Polymer Sheet B, indicating that the observation results were not sufficient. This is presumably because the Young's modulus of Polymer Sheet B is large and it cannot follow the unevenness of the surface roughness of the carbon steel block, resulting in an air layer being formed between them. Therefore, the Young's modulus of the polymer sheet is preferably 2000 MPa or less.

[0045] In addition to those separated from the elastomer, the constituent material of the polymer sheet may be formed by subjecting the elastomer to a surface treatment, for example, by non-sticking treatment using a sliding coating (the non-sticking treatment requires a thickness of, for example, 30 μm or more), and the same effect can be obtained. The polymer sheet may be formed and configured by any method. Further, an adhesive layer may be present between the ultrasonic probe and the elastomer member, and between the elastomer member and the polymer sheet.

[0046] (Comparative Example 2) An ultrasonic flaw detection test was carried out under the same conditions as in Example 1 with a configuration in which only Polymer Sheet A was arranged for the same ultrasonic probe as in Example 1. A load was applied up to a maximum of 0.5 MPa, but no flaw detection signal was obtained.

[0047] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0048] 1... Ultrasonic inspection device, 2... Ultrasonic probe, 3... Vibrator, 5... Ultrasonic element, 6... Receiving plate, 9... Contact member, 10... Contact medium, 11... Sheet-like member, 12... Load application jig, 13... Bonding layer, 14... Reversible first adhesive layer, 15... Polymer layer, 16... Second adhesive layer.

Claims

1. A sonic probe comprising a vibrator configured to perform at least one of transmitting and receiving sound waves, and having a sonic functional surface constituting at least one of a sound wave transmitting surface and a sound wave receiving surface, a contact member having a first surface that directly contacts or contacts via an intermediate member the sonic functional surface of the sonic probe, a second surface opposite to the first surface, a contact medium containing an elastomer, and a sheet-like member containing a polymer and laminated with the contact medium so as to be in contact with the second surface over the entire surface, and a load mechanism for applying a load to the contact member, the polymer includes at least one selected from the group consisting of polyester, polyethylene, polypropylene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyphenylene sulfide, and polyvinylidene chloride, the sheet-like member has a thickness of 1 / 250 or more and 1 / 2 or less of the wavelength λ of the sound wave transmitted from the vibrator and propagating through the sheet-like member, or a thickness of 10 μm or more and 1 mm or less, a sonic inspection device.

2. The sonic inspection device according to claim 1, wherein the sheet-like member has a uniform thickness.

3. The sonic inspection device according to claim 1 or claim 2, wherein the elastomer contained in the contact medium has a Young's modulus of 0.1 MPa or more and 10 MPa or less, and the polymer contained in the sheet-like member has a Young's modulus higher than that of the elastomer and 2000 MPa or less.

4. The elastomer in the ultrasonic inspection device according to any one of claims 1 to 3 includes at least one selected from the group consisting of polyester-based thermoplastic elastomers, styrene-butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, isobutylene-isoprene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, silicone rubber, fluorine rubber, chlorosulfonated polyethylene, acrylic rubber, and epichlorohydrin rubber.

5. The ultrasonic inspection device according to any one of claims 1 to 4 includes a bonding layer including a first adhesive layer having reversibility.

6. The first adhesive layer in the ultrasonic inspection device according to claim 5 includes any one of a temperature-sensitive adhesive, a photoirradiation curable agent, a heat-expandable agent, a thermal expansion agent, and a photo-structural change agent.

7. The bonding layer in the ultrasonic inspection device according to claim 5 or 6 further includes at least one selected from a polymer layer and a second adhesive layer.

8. The ultrasonic probe in the ultrasonic inspection device according to any one of claims 1 to 7 is an ultrasonic transducer.

9. A step of arranging a contact member including a contact medium containing an elastomer and a sheet-like member containing a polymer, the contact member being laminated so as to be in full contact with the contact medium and the second surface, and the sheet-like member being in contact with the object to be inspected through a contact member having a first surface that is in direct contact with or in contact with the ultrasonic functional surface of the ultrasonic probe via an intermediate member, the ultrasonic probe having a vibrator configured to perform at least one of transmitting and receiving ultrasonic waves and having an ultrasonic functional surface that constitutes at least one of the transmitting surface and the receiving surface of the ultrasonic waves; A step of applying a load to the contact member to press and contact the contact medium against the object to be inspected through the sheet-like member; A step of performing non-destructive inspection of the object to be inspected by acoustic waves using the acoustic wave probe while pressing the contact member against the object to be inspected; A step of moving the acoustic wave probe on the object to be inspected while bringing the sheet-like member into contact with the object to be inspected while applying a load to the contact member; The polymer includes at least one selected from the group consisting of polyester, polyethylene, polypropylene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyphenylene sulfide, and polyvinylidene chloride; The sheet-like member is an acoustic wave transmitted from the vibrator, and has a thickness of 1 / 250 or more and 1 / 2 or less of the wavelength λ of the acoustic wave propagating through the sheet-like member, or a thickness of 10 μm or more and 1 mm or less, an acoustic wave inspection method.

10. The acoustic wave inspection method according to claim 9, wherein the sheet-like member includes a polymer sheet.

11. The elastomer contained in the contact medium has a Young's modulus of 0.1 MPa or more and 10 MPa or less, and the polymer contained in the sheet-like member has a Young's modulus higher than that of the elastomer and 2000 MPa or less, the acoustic wave inspection method according to claim 9 or claim 10.

12. The step of performing the non-destructive inspection includes a step of transmitting ultrasonic waves used as the acoustic waves from the acoustic wave probe to the object to be inspected through the contact member, and a step of receiving a reflected wave from the object to be inspected with the acoustic wave probe through the contact member, the acoustic wave inspection method according to any one of claims 9 to 11.

13. A contact member used for an acoustic wave probe of an acoustic wave inspection device, Having a first surface and a second surface opposite to the first surface, a contact medium containing an elastomer, and a sheet-like member laminated so as to be in full contact with the second surface of the contact medium and containing a polymer. The polymer includes at least one selected from the group consisting of polyester, polyethylene, polypropylene, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polyphenylene sulfide, and polyvinylidene chloride, The sheet-like member is a contact member having a thickness of 1 / 250 or more and 1 / 2 or less of the wavelength λ of the sound wave transmitted from the vibrator of the ultrasonic probe and propagating through the sheet-like member, or a thickness of 10 μm or more and 1 mm or less.

14. The contact member according to claim 13, wherein the sheet-like member includes a polymer sheet.

15. The contact member according to claim 13 or claim 14, wherein the elastomer contained in the contact medium has a Young's modulus of 0.1 MPa or more and 10 MPa or less, and the polymer contained in the sheet-like member has a Young's modulus higher than that of the elastomer and 2000 MPa or less.

16. The contact member according to any one of claims 13 to 15, wherein the elastomer includes at least one selected from the group consisting of polyester-based thermoplastic elastomer, styrene-butadiene rubber, isoprene rubber, butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, isobutylene-isoprene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, silicone rubber, fluorine rubber, chlorosulfonated polyethylene, acrylic rubber, and epichlorohydrin rubber.

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