JP2014153221A - Detection system for oxide layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detection system for an oxide layer capable of detecting the oxide layer by a photoluminescence method using a down-sized exciting light source.SOLUTION: A detection system 10 for an oxide layer detects that the oxide layer is created on a turbine blade 1 on which a heat barrier layer is formed via an adhesion layer on a metal substrate. The detection system includes a light source device 20 that outputs continuous oscillation laser light 21 as excitation light to radiate it to a turbine blade 1, and a spectroscopic instrument 40 that detects fluorescent light that is emitted from the oxide layer created on the turbine blade 1 by continuous oscillation laser light 21.

Description

  The present invention relates to an oxide layer detection system capable of detecting an oxide layer generated in a specimen such as a turbine blade having a heat shielding layer formed through an adhesion layer.

  As shown in FIG. 1 (a), the turbine blade 1 of the gas turbine for thermal power generation is used at a high temperature, and therefore, a heat shielding layer 4 is provided on the surface of the metal substrate 2 via the adhesion layer 3. It has a configuration. For example, the adhesion layer 3 is made of MCrAlY alloy (M = Ni, Co or a combination thereof), and the heat shield layer 4 is made of yttria stabilized zirconia (YSZ).

  As shown in FIG. 1B, when the turbine blade 1 is used for a long time in a high-temperature oxidizing atmosphere, a thermal oxide (hereinafter referred to as an interfacial oxide layer 5) is formed between the adhesion layer 3 and the heat shield layer 4. It is formed. When the interfacial oxide layer 5 is formed, the bonding strength of the heat shield layer 4 is reduced, an air layer is generated, and the heat shield layer 4 is peeled from the adhesion layer 3. And when this peeling area increases, as shown in FIG.1 (c), a part of thermal insulation layer 4 will peel.

  Therefore, it is important to discover the interfacial oxide layer 5 at an early stage before such peeling of the thermal barrier layer 4 occurs.

  As a technique for detecting the interfacial oxide layer 5 in a nondestructive manner, a photoluminescence method is exemplified. The photoluminescence method is a method in which the interface oxide layer 5 is photoexcited and the light emission is measured. For example, as shown in FIG. 2, a photoluminescence method is performed using a laser light source 100 that irradiates a turbine blade 1 that is a subject with laser light, and a spectroscopic device 101 that detects light emission excited by the laser light. Can do.

Since the elements constituting the adhesion layer 3 are Ni, Co, Cr, Al, and Y, the interface oxide layer 5 includes NiCr ₂ O ₄ , Cr ₂ O ₃ , NiO, Al ₂ O ₃ , AlYO ₃ , Al Oxides such as ₅ Y ₃ O ₁₂ are present. Therefore, when the interfacial oxide layer 5 in which Cr ³⁺ is present in Al ₂ O ₃ is irradiated with a laser beam from the laser light source 100 to be photoexcited, red light is emitted. If red light is observed in the spectroscopic device 101, it can be determined that the interface oxide layer 5 exists between the adhesion layer 3 and the heat shield layer 4.

  A method for evaluating the peeling damage of the thermal barrier layer based on such photoexcitation by laser light has been proposed (see, for example, Patent Document 1). In this method, a rare earth oxide layer is formed in advance between the heat shield layer and the metal substrate. On the other hand, the exhaust gas passage is irradiated with X-rays or ultraviolet rays. When the thermal barrier layer is peeled off and the rare earth oxide layer reaches the exhaust gas passage with the exhaust gas, fluorescence is observed from the rare earth oxide layer by X-rays. It is.

  However, the evaluation method according to Patent Document 1 detects that after the interface oxide layer is formed and the heat shield layer is peeled off. Therefore, it cannot be detected early that the interfacial oxide layer has been formed.

  If the photoluminescence method is simply applied to the turbine blade, the attenuation of light in the thermal barrier layer is large, so a laser with a relatively high light intensity such as a W-class laser is required to reach the interface oxide layer. A light source is required. It is difficult to bring such a high-intensity laser light source to the site where the gas turbine is installed. In particular, when a pulse laser is used, a large-capacity power source (for example, 200 V) is required, and a large-sized device that requires water cooling must be used. For this reason, a light source device that outputs such a pulsed laser is not suitable for a site where a thermal power generation gas turbine is installed.

  Such a problem can occur not only in turbine blades of gas turbines but also in all objects that are used in a high-temperature oxidizing atmosphere and can form an oxide layer.

JP 2005-146291 A

  In view of the above circumstances, an object of the present invention is to provide an oxide layer detection system capable of detecting an oxide layer by a photoluminescence method using a miniaturized excitation light source.

  A first aspect for achieving the above object is an oxide layer detection system for detecting that an oxide layer is formed on a specimen in which a heat shielding layer is formed on a metal substrate via an adhesion layer. A light source device that outputs continuous wave laser light or LED light as excitation light and irradiates the subject, and a fluorescence detection device that detects fluorescence emitted by the excitation light from the oxide layer generated on the subject; An oxide layer detection system comprising:

  The first aspect employs a light source device that outputs continuous wave laser or LED light as excitation light. Such a light source device is small in size, operates with a normal commercial power supply (100 V), and does not require water cooling. Therefore, the present detection system can be configured at the site where the subject is installed, and it can be inspected whether or not an oxide layer is generated on the subject.

  According to a second aspect of the present invention, in the oxide layer detection system according to the first aspect, the first end and the second end are provided on one side, and the third end is provided on the opposite side. A branch optical fiber, wherein the first end is optically connected to the light source device, the second end is optically connected to the fluorescence detection device, and the third end is the light source An oxide layer detection system is configured to irradiate the subject with excitation light from an apparatus and to receive the fluorescence emitted from the subject.

  In the second aspect, since the excitation light can be guided to an arbitrary position and the fluorescence from the subject can be received at the arbitrary position, the oxide layer can be formed regardless of the relative arrangement of the subject, the light source device, and the spectroscopic device. A presence / absence check can be performed.

  According to a third aspect of the present invention, in the oxide layer detection system according to the first or second aspect, the fluorescence detection device is a spectroscopic device that analyzes a spectrum of fluorescence emitted from the subject. The spectroscopic device is an oxide layer detection system that detects, from the spectrum, the wavelength of fluorescence emitted from the oxide layer generated in the subject by excitation light.

  In the third aspect, fluorescence can be detected using a spectroscopic device.

  According to a fourth aspect of the present invention, in the oxide layer detection system according to the third aspect, the system includes an analysis device that inputs the spectrum obtained by the spectroscopic device as information. The oxide layer detection system is characterized in that noise is removed by performing median filtering for each of the wavelengths.

  In the fourth aspect, since spike noise is excluded from the spectrum, fluorescence can be detected more reliably.

  According to a fifth aspect of the present invention, in the oxide layer detection system according to the fourth aspect, the analysis device removes, as background light, other than the wavelength of the fluorescence emitted by the oxide layer by excitation light. An oxide layer detection system characterized by:

  In the fifth aspect, since background light is excluded from the spectrum, fluorescence can be detected more reliably.

  According to a sixth aspect of the present invention, in the oxide layer detection system according to the first or second aspect, the fluorescence detection device is configured to receive incident light including fluorescence and background light from a subject, A first photomultiplier tube and a second photomultiplier tube that respectively output a first signal and a second signal representing the intensity of incident light, wherein the first photomultiplier tube comprises the oxide The incident light is incident through the first interference filter whose center wavelength is the wavelength of the fluorescence emitted from the layer by the excitation light, and the second photomultiplier tube has the second interference whose center wavelength is the wavelength of the background light. Detecting an oxide layer, comprising: an oscilloscope that receives the incident light through a filter and uses a difference between the first signal and the second signal as a signal representing the intensity of fluorescence from a subject. In the system.

  In the sixth aspect, the fluorescence from the subject can be detected by removing the influence of background light.

  According to a seventh aspect of the present invention, in the oxide layer detection system according to the sixth aspect, the chopper device capable of blocking the excitation light output from the light source device and the oscilloscope are excited by the chopper device. An oxide layer detection system that corrects the first signal and the second signal so that a difference between the first signal and the second signal when light is blocked is eliminated. .

  In the seventh aspect, the influence of background light can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the detection system of the oxide layer which can detect an oxide layer with a photoluminescence method using the reduced excitation light source is provided.

It is sectional drawing of a turbine blade. It is the schematic which shows the detection method of the interface oxide layer by the photoluminescence method. 1 is a schematic configuration diagram of an oxide layer detection system according to Embodiment 1. FIG. The spectrum obtained by the spectroscopic device is subjected to noise processing. 6 is a schematic configuration diagram of an oxide layer detection system according to Embodiment 2. FIG. It is a schematic block diagram of the detection system of the oxide layer which concerns on Embodiment 3. It is a schematic block diagram of the detection system of the oxide layer which concerns on Embodiment 4. It is an example of a display with an oscilloscope showing the 1st signal and the 2nd signal. It is the example of a display with an oscilloscope showing the 1st signal and the 2nd signal at the time of intercepting excitation light with a chopper device.

<Embodiment 1>
An oxide layer detection system (hereinafter also simply referred to as a detection system) according to the present embodiment is directed to a turbine blade 1 constituting a thermal power generation gas turbine as an example of a subject. As described above, the turbine blade 1 is formed by forming the heat shielding layer 4 on the metal base 2 via the adhesion layer 3 (see FIG. 1). In the turbine blade 1, the thermal oxidation of the metal substrate 2 is protected by the heat shield layer 4, but an interfacial oxide layer 5 (oxide layer) is generated at the interface between the adhesion layer 3 and the heat shield layer 4 over time. obtain.

  Hereinafter, a detection system capable of detecting that the interfacial oxide layer 5 has occurred in the turbine blade 1 will be described.

  FIG. 3 is a schematic configuration diagram of the oxide layer detection system according to the first embodiment. As illustrated, the detection system 10 includes a light source device 20, an optical system 30, a spectroscopic device 40 that is an example of a fluorescence detection device, and an analysis device 50.

The light source device 20 can irradiate a continuous wave laser 21 as excitation light. As the continuous wave laser 21, Ar laser, Kr laser, CO ₂ laser, YAG laser, Nd: YAG laser, YVO ₄ laser, YLF laser, YAlO ₃ laser, GdVO ₄ laser, Y ₂ O ₃ laser, ruby laser, alexandrite There are a laser, a titanium sapphire laser, a helium cadmium laser, and the like. What is necessary is just to select from these lasers according to the material contained in the interface oxide layer 5 to be measured.

  On the optical axis of the light source device 20, an ND filter (a neutral density filter) 22 and a beam magnifying lens 23 are arranged. The amount of light entering the beam expanding lens 23 is adjusted by the ND filter 22. The beam expanding lens 23 adjusts the focal length of the continuous wave laser 21.

  In the present embodiment, a concave lens is used as the beam expanding lens 23, and the turbine blade 1 is disposed at a position where the diameter of the continuous wave laser 21 is expanded to some extent. It is also possible to use a convex lens as the beam magnifying lens 23, condense the laser beam once, and arrange the turbine blade 1 behind the condensing point.

  The optical system 30 receives the fluorescence emitted from the turbine blade 1 and guides it to the spectroscopic device 40. The optical system 30 according to the present embodiment includes a light receiving unit 31, an optical fiber 32, and a long pass filter 33.

  The light receiver 31 is disposed at a predetermined distance from the turbine blade 1, and a long pass filter 33 is disposed between the light receiver 31 and the turbine blade 1.

  In addition to the fluorescence emitted from the turbine blade 1 being incident on the light receiving unit 31, the reflected light from the surface of the turbine blade 1 and ambient ambient light are also incident. These fluorescence, reflected light, ambient light, and the like are collectively referred to as incident light.

  The long pass filter 33 is a filter that does not transmit light of a specific wavelength. Specifically, the long pass filter 33 has a specific wavelength set so as to mainly remove the reflected light from the surface of the turbine blade 1 from the incident light to the light receiving unit 31.

  The incident light from which the reflected light is thus removed is guided from the light receiving unit 31 to the spectroscopic device 40 via the optical fiber 32.

  The spectroscopic device 40 analyzes the spectrum of the fluorescence generated by the continuous wave laser 21 irradiated to the turbine blade 1 from the light source device 20, and determines the wavelength of the fluorescence emitted by the excitation light from the interface oxide layer 5 generated on the turbine blade 1. A device that detects from the spectrum.

  The spectroscopic device 40 according to the present embodiment can split incident light incident from the optical fiber 32 with a diffraction grating, receive the light with an ICCD, and analyze the spectrum of the incident light. That is, a spectrum representing the intensity for each wavelength of the incident light incident on the light receiving unit 31 is obtained.

  If the spectrum analyzed by the spectroscopic device 40 includes a wavelength of fluorescence emitted by irradiating the turbine blade 1 with excitation light, it is determined that the interface oxide layer 5 is generated in the turbine blade 1. To do.

If the interfacial oxide layer 5 is formed on the turbine blade 1, Cr ³⁺ exists in Al ₂ O ₃ of the interfacial oxide layer 5. For example, when an Nd: YAG laser is used as the light source device 20 and the turbine blade 1 is irradiated with a continuous wave laser 21 having a wavelength of 532 nm and an output of 200 mW, Cr ³⁺ contained in the interface oxide layer 5 is excited, and the red light is emitted over several ms. Emits fluorescence. The fluorescence is known to have a wavelength of 694.3 nm or 692.9 nm.

Therefore, if the intensity of the wavelength of the fluorescence emitted from Cr ³⁺ can be recognized to some extent in the spectrum obtained by the spectroscopic device 40, it is determined that the interfacial oxide layer 5 is formed on the turbine blade 1. Can do.

  The light incident on the light receiving unit 31 may include not only fluorescence emitted from the turbine blade 1 by light excitation but also ambient ambient light. Further, noise may occur in the ICCD of the spectroscopic device 40. Therefore, the spectrum obtained by the spectroscopic device 40 may include noise on a transient spike.

  In order to exclude the influence of such noise, the detection system 10 may include an analysis device 50 that removes spectral noise.

  The analysis device 50 according to the present embodiment includes a CPU (central processing unit), a storage device (RAM, hard disk, etc.), an input / output device (keyboard, mouse, display, etc.), and various interfaces (USB, network adapter, etc.). A general information processing apparatus (personal computer (PC)).

  The analysis device 50 has a function of inputting a spectrum as information from the spectroscopic device 40 and executing a predetermined noise removal process on the spectrum.

  Hereinafter, median filter processing and background light removal processing will be exemplified as specific noise removal processing.

  In the median filtering process, for each wavelength included in the spectrum, 2N + 1 wavelengths including the wavelength and the preceding and following N wavelengths are selected, and the intensity of the 2N + 1 wavelengths having an intermediate value is determined as the intensity of the wavelength. It is processing to do. Of course, the number of wavelengths to be selected may be 11 in total, for example, N = 5.

  By this median filter processing, noise caused by ICCD of the spectroscopic device 40 included in the spectrum can be reduced, and spike-like noise can be removed.

  FIG. 4A shows a case where the spectrum obtained by the spectroscopic device 40 is subjected to median filter processing (N = 5). The horizontal axis represents the wavelength, and the vertical axis represents the spectral intensity. Each line of A to C represents a spectrum when the subjects A to C are irradiated with excitation light. The subject A is a metal substrate provided with a heat shielding layer through an adhesion layer and heated at 1100 ° C. for 1000 hours. The subject B has the same configuration as the subject A, and is heated at 1100 ° C. for 100 hours. The subject C has the same configuration as the subject A, and is not heated.

As shown in the figure, the spectra of the subjects A to C have spike-like noise removed by the median filter process, and it is easy to confirm whether the fluorescence of Cr ³⁺ exists in the spectrum.

Further, when each spectrum was examined, for the specimen A and the specimen B, a spectrum was observed in the vicinity of a wavelength of 694 nm of Cr ³⁺ fluorescence. On the other hand, no spectrum was observed for the subject C. From this result, it was confirmed that the interface oxide layer exists in the specimen A and the specimen B, and the interface oxide layer does not exist in the specimen C.

When comparing the specimen A and the specimen B, the spectrum of the specimen A having a long heat treatment time is strong. Therefore, it was confirmed that the longer the heat treatment time, the more the Cr ³⁺ is in the interface oxide layer, and the stronger the fluorescence intensity is.

  Note that broadband luminescence was observed on the longer wavelength side than the wavelength of 694 nm.

Next, background light removal processing will be described. The fluorescence of Cr ³⁺ has a wavelength region of 690 to 698 nm including the tail. Except for the fluorescence wavelength region, it can be regarded as background light.

  Therefore, a background light spectrum is created based on the measurement points of 680 to 690 nm and 698 to 708 nm before and after the wavelength region, and the background light spectrum is subtracted from the spectrum obtained by the spectroscopic device 40.

  For example, a background light spectrum is created for the spectrum after the median filter processing shown in FIG. 4A, and the subtracted spectrum is shown in FIG. 4B.

  As shown in the figure, the spectral intensity was almost zero in the wavelength region other than the wavelength of 690 to 698 nm. By performing background light removal processing in this way, a spectrum from which the influence of background light is removed can be obtained. Based on this spectrum, it is possible to easily determine whether or not an interfacial oxide layer has occurred in the specimen by confirming the presence or absence of fluorescence generated by the excitation light.

  According to the detection system 10 having the configuration described above, the turbine blade 1 is irradiated with the continuous wave laser 21 from the light source device 20 and the fluorescence is confirmed by the spectrum analyzed by the spectroscopic device 40. It can be determined whether or not the interface oxide layer 5 is formed.

  In particular, in the inspection system according to the present embodiment, a device that outputs a continuous wave laser 21 is employed as the light source device 20. The light source device 20 capable of outputting the continuous wave laser 21 is small in size, operates with a normal commercial power supply (100 V), and does not require water cooling. Therefore, it is possible to configure the detection system 10 at the site where the thermal power generation gas turbine is installed, and inspect whether or not the interface oxide layer 5 is generated on the turbine blade 1 at that site.

<Embodiment 2>
FIG. 5 is a schematic configuration diagram of the detection system according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same thing as Embodiment 1, and the overlapping description is abbreviate | omitted.

  As shown in the figure, the light source device 20 according to this embodiment uses a device that emits LED light 24 as excitation light. The color (wavelength) of the LED light is not particularly limited, and may be appropriately selected according to the material included in the interface oxide layer 5 to be measured.

  A condenser lens 25 is attached to the LED light irradiation port of the light source device 20, and the focus of the LED light 24 can be adjusted. Here, the condensing lens 25 is adjusted so that the turbine blade 1 is positioned at a position where the diameter of the LED light 24 is increased to some extent.

  As in the first embodiment, the detection system 10 according to the present embodiment irradiates the turbine blade 1 with the LED light 24 from the light source device 20 and confirms the fluorescence in the spectrum analyzed by the spectroscopic device 40, thereby It can be determined whether or not the interfacial oxide layer 5 is formed on the blade 1.

  In particular, a device that outputs LED light 24 is employed as the light source device 20. The light source device 20 is suitable as a simple excitation light source because it is less expensive than a light source device that outputs laser light and is easily available. Therefore, the detection system 10A according to the present embodiment can easily and inexpensively implement whether or not the interface oxide layer 5 is generated on the turbine blade 1 at the site where the thermal power generation gas turbine is installed. .

<Embodiment 3>
FIG. 6 is a schematic configuration diagram of a detection system according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same thing as Embodiment 1, and the overlapping description is abbreviate | omitted.

  As shown in the figure, the detection system 10 </ b> B according to the present embodiment has an optical system 30 </ b> B including a bifurcated optical fiber 34.

  The bifurcated optical fiber 34 is one in which one end side of the optical fiber is branched into two, and each end is defined as a first end 35, a second end 36, and a third end 37. The first end 35 is optically connected to the light source device 20, and the second end 36 is optically connected to the spectroscopic device 40. The third end portion 37 is a portion that irradiates the turbine blade 1 with excitation light from the light source device 20 and receives fluorescence emitted from the turbine blade 1, and a probe 38 is connected to the third end portion 37. ing.

  That is, the excitation light output from the light source device 20 is guided from the first end portion 35 to the third end portion 37 and is irradiated to the turbine blade 1 via the lens 39 disposed in the probe 38. The fluorescence emitted from the turbine blade 1 by the excitation light is received by the third end 37 through the lens 39 and guided to the spectroscopic device 40 from the second end 36.

  In this way, by using the two-branch optical fiber 34, the excitation light from the light source device 20 can be guided to an arbitrary position, and the fluorescence from the turbine blade 1 can be guided to the spectroscopic device 40 from that position. . That is, according to the detection system 10B according to the present embodiment, excitation light can be guided to an arbitrary position and fluorescence from the turbine blade 1 can be received at an arbitrary position. Therefore, the turbine blade 1, the light source device 20, and the spectroscopic light can be received. The presence or absence of the interfacial oxide layer 5 can be inspected regardless of the relative arrangement of the device 40.

<Embodiment 4>
FIG. 7 is a schematic configuration diagram of a detection system according to the present embodiment. In addition, the same code | symbol is attached | subjected to the same thing as Embodiment 1-3, and the overlapping description is abbreviate | omitted.

  The detection system 10C according to the present embodiment uses a fluorescence detection device having a photomultiplier tube (PMT). The photomultiplier tubes A and B are devices that receive light and convert it into an electrical signal.

  Specifically, the fluorescence detection device 60 has a T-shaped case 61, and the second end 36 of the bifurcated optical fiber 34 is optically connected to one end of the T-shape (hereinafter referred to as the incident portion 61c). Has been. The remaining two ends of the T-shape (hereinafter referred to as measurement units 61a and 61b) have a photomultiplier tube A (first photomultiplier tube) and a photomultiplier tube B (second photomultiplier tube). Is arranged.

  Further, in the case 61, a first interference filter 62a, a second interference filter 62b, and a cut filter 62c are arranged in the measurement unit 61a, the measurement unit 61b, and the incident unit 61c, respectively.

  The interference filter is a filter that can selectively transmit light in an arbitrary wavelength range. The first interference filter 62a uses the wavelength of the fluorescence emitted from the turbine blade 1, for example, 694 nm as the center wavelength. The second interference filter 62b uses the wavelength of background light (in particular, background light in the vicinity of the fluorescence wavelength), for example, 684 nm as the center wavelength. The cut filter 62c transmits only necessary light on the long wavelength side and does not transmit light on the short wavelength side. For example, the cut filter 62c does not transmit light having a wavelength shorter than 600 nm.

  Further, there are lenses between the first interference filter 62a and the photomultiplier tube A, between the second interference filter 62b and the photomultiplier tube B, and between the cut filter 62c and the second end 36, respectively. 63 is arranged. Further, a half mirror 64 is disposed between the first interference filter 62a, the second interference filter 62b, and the cut filter 62c.

  In such a fluorescence detection device 60, incident light (including fluorescence and background light from the turbine blade 1) is incident on the incident portion 61c from the bifurcated optical fiber 34. The incident light is enlarged to a predetermined diameter by the lens 63, and only light having a wavelength longer than 532 nm reaches the half mirror 64 by the cut filter 62 c.

  Incident light is branched into the first photomultiplier tube A and the second photomultiplier tube B by the half mirror 64.

  Incident light that has passed through the first interference filter 62 a is condensed on the first photomultiplier tube A via the lens 63. Since only the wavelength of the fluorescence emitted from the turbine blade 1 is selected by the first interference filter 62a, the intensity related to the wavelength of the fluorescence is output as an electric signal. This electric signal is referred to as a first signal. The first signal is input to CH1 of the oscilloscope 70.

  Incident light that has passed through the second interference filter 62 b is condensed on the second photomultiplier tube B via the lens 63. Since only the wavelength of the background light is selected by the second interference filter 62b, the intensity related to the wavelength of the background light is output as an electric signal. This electric signal is referred to as a second signal. The second signal is input to CH2 of the oscilloscope 70.

  FIG. 8 is a display example on an oscilloscope representing the first signal and the second signal.

As shown in FIG. 8A, CH1 is a first signal representing the intensity of light detected through the first interference filter 62a, and the background light and the fluorescence (Cr ³⁺ of the Cr ³⁺⁾ from the turbine blade 1 (Fluorescence). On the other hand, CH2 is a second signal representing the intensity of light detected through the second interference filter 62b, and includes only background light.

  Therefore, as shown in FIG. 8B, the difference between the first signal (CH1) and the second signal (CH2) is a signal representing only the intensity of the fluorescence from the turbine blade 1.

  As described above, according to the detection system 10C according to the present embodiment, the influence of the background light can be excluded, and the fluorescence intensity signal from the turbine blade 1 can be obtained more accurately. Based on the signal, Whether or not the interfacial oxide layer 5 is generated on the turbine blade 1 can be accurately determined.

  Note that the background light has the same signal level in both the photomultiplier tubes A and B due to the difference in the characteristics of the photomultiplier tubes A and B and the difference in the characteristics of the first interference filter 62a and the second interference filter 62b. It is not always detected. Therefore, as shown in FIG. 7, a chopper device 80 is provided in the light source device 20 as follows.

  The chopper device 80 is a device that periodically blocks the excitation light output from the light source device 20. Further, when the chopper device 80 is blocking / not blocking the optical axis of the excitation light, the chopper device 80 outputs a synchronization signal (close / open) indicating that fact. This synchronization signal is input to the oscilloscope 70 (TRIG).

  FIG. 9A shows a synchronization signal, and FIG. 9B shows a display example of the intensity of the excitation light output from the light source device 20 on an oscilloscope. Since the excitation light is periodically blocked by the chopper device 80, the intensity of the excitation light changes in a rectangular wave shape. The synchronization signal is synchronized with the timing when the chopper device 80 blocks the excitation light.

  FIG. 9 (c) is an example of display on the oscilloscope of the first signal (CH1) when the chopper device 80 is periodically interrupted.

  When the chopper device 80 periodically blocks the excitation light, the fluorescence from the turbine blade 1 emitted by the excitation light is also periodic. Accordingly, the first signal representing the intensity of the fluorescence also changes periodically.

  When the chopper device 80 is “open”, the first signal is intensity including fluorescence from the turbine blade 1 and some background light in the section α corresponding to “open”. On the other hand, when the chopper device 80 is “closed”, no fluorescence is generated. Therefore, the first signal is the intensity of only the background light in the section β corresponding to “closed”.

  FIG. 9D is an example of display on the oscilloscope of the second signal (CH2) when the chopper device 80 is periodically interrupted.

  The second signal is a signal obtained by selectively detecting only background light in the fluorescence detection device 60. Therefore, the second signal represents only the intensity of the background light.

  Since the intensity of the first signal in the section β and the intensity of the second signal represent the same background light intensity, they must be at the same level. Therefore, the first signal and the second signal are corrected so that the intensity of the background light becomes the same.

  Then, after such correction, as shown in FIG. 9 (e), the difference between the first signal and the second signal is set as the intensity of the fluorescence from the turbine blade 1.

  Thus, by correcting the intensity of the background light obtained by the photomultiplier tube A and the photomultiplier tube B to the same level, the difference in the characteristics of the photomultiplier tubes A and B, the first interference filter 62a And the influence by the difference in the characteristic of the 2nd interference filter 62b can be excluded.

  As described above, according to the detection system 10C using the chopper device 80, the influence of the background light can be further excluded, so that the fluorescence intensity signal from the turbine blade 1 can be obtained more accurately. Based on the signal, it can be accurately determined whether or not the interfacial oxide layer 5 is generated in the turbine blade 1.

<Other embodiments>
Although the turbine blade used in the gas turbine for thermal power generation is the subject, the present invention is not limited to this. That is, the present invention can be generally applied to an object in which a heat shielding layer is formed on a metal substrate via an adhesion layer.

  In the first embodiment, noise removal processing is performed by the PC 50 for the spectrum analyzed by the spectroscopic device 40, but this is not always necessary. In addition, both the median filter process and the background light removal process are performed as the noise removal process, but either one may be used.

  In the fourth embodiment, the chopper device 80 is used, but it is not essential. That is, the intensity of the fluorescence from the turbine blade 1 may be obtained by taking the difference between the first signal and the second signal obtained by the photomultiplier tube.

  INDUSTRIAL APPLICABILITY The present invention can be used in the industrial field where non-destructive inspection is performed to determine whether or not oxide is generated in a specimen used at a high temperature such as a turbine blade.

1 Turbine blade (subject)
2 Metal substrate 3 Adhesion layer 4 Heat shield layer 5 Interfacial oxide layer 10, 10A, 10B, 10C detection system 20 Light source device 21 Continuous wave laser 24 LED light 34 Bifurcated optical fiber 40 Spectrometer 50 Analysis device 60 Fluorescence detection device 62a First interference filter 62b Second interference filter 70 Oscilloscope 80 Chopper device

Claims (7)

An oxide layer detection system for detecting that an oxide layer is formed on a specimen in which a heat shielding layer is formed on a metal substrate via an adhesion layer,
A light source device that outputs continuous wave laser light or LED light as excitation light and irradiates the subject;
An oxide layer detection system comprising: a fluorescence detection device that detects fluorescence emitted by the excitation light generated by the oxide layer generated in the subject. In the oxide layer detection system according to claim 1,
A bifurcated optical fiber having a first end and a second end on one side and a third end on the opposite side;
The first end is optically connected to the light source device;
The second end is optically connected to the fluorescence detection device;
The third end is configured to irradiate the subject with excitation light from the light source device and to receive the fluorescence emitted from the subject. Detection system. In the detection system of the oxide layer according to claim 1 or 2,
The fluorescence detection device is a spectroscopic device that analyzes a spectrum of fluorescence emitted from the subject,
The said spectroscopic device detects the wavelength of the fluorescence which the oxide layer produced in the said test object discharge | releases with excitation light from the said spectrum. The detection system of the oxide layer characterized by the above-mentioned. In the oxide layer detection system according to claim 3,
An analysis device for inputting the spectrum obtained by the spectroscopic device as information;
The said analysis apparatus removes noise by performing a median filter process about each wavelength of a spectrum. The oxide layer detection system characterized by the above-mentioned. The oxide layer detection system according to claim 4,
The said analysis apparatus removes except the wavelength of the fluorescence which the said oxide layer emits with excitation light as background light. The oxide layer detection system characterized by the above-mentioned. In the detection system of the oxide layer according to claim 1 or 2,
The fluorescence detection apparatus is configured to receive a first photomultiplier tube from which incident light including fluorescence and background light from a subject is guided and output a first signal and a second signal representing the intensity of the incident light, respectively. Having a second photomultiplier tube;
In the first photomultiplier tube, the incident light is incident through a first interference filter whose center wavelength is the wavelength of fluorescence emitted from the oxide layer by excitation light,
The second photomultiplier tube receives the incident light through a second interference filter having a center wavelength of the wavelength of the background light,
An oxide layer detection system comprising: an oscilloscope that uses a difference between the first signal and the second signal as a signal representing the intensity of fluorescence from a subject. The oxide layer detection system according to claim 6,
A chopper device capable of blocking excitation light output from the light source device;
The oscilloscope corrects the first signal and the second signal so that a difference between the first signal and the second signal when the chopper device blocks excitation light is eliminated. Oxide layer detection system.

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