A method for preparing zirconium alloy transmission electron microscope samples based on self-ion irradiation

Abstract

The invention discloses a method for preparing a zirconium alloy transmission electron microscope sample based on self-ion irradiation, comprising: preparing a zirconium alloy metal sheet, pre-thinning a first side of the zirconium alloy metal sheet, and forming a pit on the first side; irradiating the zirconium alloy metal sheet with heavy ions, protecting the first side of the zirconium alloy metal sheet, and performing electrolytic double-spray thinning on the second side of the zirconium alloy metal sheet; performing transmission electron microscope analysis on the thinned zirconium alloy metal sheet, and judging that the zirconium alloy transmission electron microscope sample is successfully prepared if the requirements are met; the invention can simply and efficiently prepare a heavy ion irradiated surface transmission electron microscope sample by pre-thinning the zirconium alloy metal sheet before irradiation and single-sided thinning after irradiation, and the method can not only obtain a large-area irradiation damaged thin area, but also effectively observe large-size irradiation damaged defects, and has wide practicality in low-energy heavy ion irradiation transmission electron microscope sample preparation and analysis.

Description

Technical Field

[0001] The invention relates to the technical field of transmission electron microscope sample preparation, and in particular to a method for preparing a zirconium alloy transmission electron microscope sample based on self-ion irradiation. Background Art

[0002] Zirconium metal has a small thermal neutron absorption cross-section. The zirconium alloy made by adding alloying elements has good mechanical properties and high-temperature water corrosion resistance. It is widely used as the cladding material of fuel elements in water-cooled reactors.

[0003] Zirconium alloy fuel element cladding is a barrier that contains the fuel core and prevents fission products and radioactive materials from entering the primary coolant. It plays a vital role in the safe operation of the reactor. In recent years, countries around the world have successively developed a variety of new zirconium alloys and carried out a large number of in-pile and out-of-pile experimental verifications. However, due to the high cost, long cycle, many interference factors of reactor irradiation, and the strong radioactivity of the irradiated samples that is not conducive to subsequent microscopic analysis, it is not conducive to the rapid screening of a large number of new zirconium alloys, which prolongs the development cycle of high-performance new zirconium alloys.

[0004] Ion irradiation, because its initial process of producing atomic displacement is very close to neutron irradiation, especially the heavy ion implanter that realizes full-element periodic self-ion irradiation, can not only not introduce other impurity elements and thus be as close to neutron irradiation as possible, but can also be used in conjunction with a transmission electron microscope to observe in situ the changes in irradiation defects in the sample with the irradiation dose, and is considered to be an important means for studying the mechanism of material irradiation damage and preliminary screening of new reactor materials. . Because Zr 2+ The depth of incidence in zirconium alloy is very shallow. Therefore, the preparation of TEM samples is the most important step in the TEM characterization process of zirconium alloy samples after self-ion irradiation. The traditional method is to first use a heavy ion implanter to perform Zr 2+ Ion irradiation, then use glue to bond and compact the irradiated surfaces of two ion-irradiated zirconium alloy sheets, after the glue solidifies, the cross section of the bonded zirconium alloy sheet is mechanically thinned (until the thickness is less than 100μm) and a disc with a diameter of 3mm is made with the bonding area as the center, and then the Φ3mm disc is double-sprayed by pitting and electrolysis to obtain a transmission electron microscope sample with a thin area of ​​irradiation damage and observe and analyze it. However, the traditional method of preparing transmission electron microscope samples of zirconium alloys after ion irradiation is very complicated, cumbersome, and time-consuming, and can only achieve the preparation of transmission electron microscope samples of zirconium alloy cross sections after ion irradiation. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the process of preparing zirconium alloy transmission electron microscope samples by traditional methods is complicated and can only realize the preparation of zirconium alloy cross-section transmission electron microscope samples after self-ion irradiation. The purpose is to provide a method for preparing zirconium alloy transmission electron microscope samples based on self-ion irradiation, which solves the problem of preparing irradiation surface transmission electron microscope samples with a shallow incidence depth.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for preparing zirconium alloy transmission electron microscope samples based on self-ion irradiation, comprising:

[0008] A zirconium alloy metal sheet is prepared by a mechanical thinning method, wherein the zirconium alloy metal sheet has a first side surface and a second side surface;

[0009] Pre-thinning the first side of the zirconium alloy metal sheet using an ion thinning instrument, and forming a pit on the first side;

[0010] Using a heavy ion implanter to perform heavy ion irradiation on the zirconium alloy metal sheet, wherein the heavy ion implantation direction is perpendicular to the first side surface of the zirconium alloy metal sheet;

[0011] Protecting the first side of the zirconium alloy metal sheet, and performing electrolytic double-spray thinning on the second side of the zirconium alloy metal sheet;

[0012] The thinned zirconium alloy metal sheet is subjected to transmission electron microscopy analysis. If the requirements are met, it is determined that the zirconium alloy transmission electron microscopy sample is successfully prepared.

[0013] Optionally, the zirconium alloy metal sheet is a zirconium alloy disc, the diameter of the zirconium alloy disc is 3 mm, and the thickness of the zirconium alloy disc is 80 μm to 100 μm.

[0014] Optionally, the pre-thinning voltage of the ion thinning instrument is 5KV, the thinning temperature is -20°C, and the thinning time is 1h;

[0015] The energy of the heavy ion implanter is 150keV.

[0016] Optionally, the first side of the zirconium alloy metal sheet is protected by a polytetrafluoroethylene film;

[0017] The volume ratio of the components of the double spray liquid used in the electrolytic double spray thinning is:

[0018] Perchloric acid: n-butanol: methanol = 3:17:30;

[0019] The temperature of electrolytic double-spray thinning is -30℃.

[0020] Specifically, a method for preparing a zirconium alloy transmission electron microscope sample based on self-ion irradiation comprises:

[0021] A zirconium alloy sheet is prepared by a mechanical thinning method, and then a plurality of zirconium alloy discs are removed from the zirconium alloy sheet by a punching machine;

[0022] Aligning an ion gun of an ion thinning instrument to the zirconium alloy wafer, and controlling the ion gun to pre-thinn the first side of the zirconium alloy wafer;

[0023] A high-purity zirconium target is loaded in a heavy ion implanter, and the first side of the pre-thinned zirconium alloy wafer is subjected to Zr 2+ Ion irradiation to obtain the irradiated zirconium alloy disc with the expected dose;

[0024] A polytetrafluoroethylene film is used to protect the first side of the zirconium alloy disc;

[0025] Adding electrolytic double-spray solution into the electrolytic double-spray instrument, and performing electrolytic double-spray thinning on the second side of the zirconium alloy disc; when the transmittance reaches a set value, removing the electrolytic double-spray solution on the zirconium alloy disc;

[0026] The thinned zirconium alloy disc is subjected to transmission electron microscopy analysis to observe the irradiation microscopic defects in the zirconium alloy disc. If the defects can be clearly observed, it is judged that the zirconium alloy transmission electron microscopy sample is successfully prepared.

[0027] Optionally, the diameter of the zirconium alloy disc is 3 mm, and the thickness of the zirconium alloy disc is 80 μm to 100 μm.

[0028] Optionally, the pre-thinning voltage of the ion thinning instrument is 5KV, the thinning temperature is -20°C, and the thinning time is 1h;

[0029] The energy of the heavy ion implanter is 150keV.

[0030] Optionally, the volume fraction ratio of the components of the double spray liquid used in the electrolytic double spray thinning is:

[0031] Perchloric acid: n-butanol: methanol = 3:17:30;

[0032] The temperature of electrolytic double-spray thinning is -30℃.

[0033] Optionally, the deflection angle of the ion gun of the ion thinning instrument relative to the central axis of the zirconium alloy disc is -5° to +5°.

[0034] Optionally, removing the electrolytic double-spray solution on the zirconium alloy disc includes: cleaning the zirconium alloy disc in multiple cups of anhydrous ethanol in turn to remove the electrolytic double-spray solution remaining on the surface of the sample.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] The present invention can simply and efficiently prepare heavy ion irradiated surface transmission electron microscope samples by pre-thinning the zirconium alloy metal sheet before irradiation and single-sided thinning after irradiation. This method can not only obtain a large area of ​​irradiation damaged thin area, but also effectively observe large-scale irradiation damage defects. It has wide practicality in low-energy heavy ion irradiation transmission electron microscope sample preparation and analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, are used to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention, and the accompanying drawings are included in and constitute a part of this specification and do not constitute a limitation of the embodiments of the present invention.

[0038] Figure 1 The present invention is a schematic flow chart of a method for preparing zirconium alloy transmission electron microscope samples based on self-ion irradiation.

[0039] Figure 2 It is a schematic diagram of the structure of the zirconium alloy disc after completing the first step according to the present invention.

[0040] Figure 3 It is a schematic diagram of the structure of the zirconium alloy disc after completing the fourth step according to the present invention. DETAILED DESCRIPTION

[0041] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation methods. It is understood that the specific implementation methods described herein are only used to explain the relevant content, rather than to limit the present invention.

[0042] It should also be noted that, for the convenience of description, only the parts related to the present invention are shown in the drawings.

[0043] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0044] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0045] In the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0046] Zirconium alloy fuel element cladding is a barrier that contains the fuel core and prevents fission products and radioactive materials from entering the primary coolant. It plays a vital role in the safe operation of the reactor. Under the harsh operating conditions of the reactor, with the extension of service time and the increase of fuel consumption, the zirconium alloy cladding may suffer from water side corrosion, hydrogen absorption, creep and fatigue caused by irradiation damage and other failure behaviors. In order to further meet the urgent needs of extending the refueling cycle and improving the economy and safety of the reactor, a variety of new zirconium alloys have been developed successively. However, due to the high cost, long cycle, many interference factors of reactor irradiation, and the strong radioactivity of the sample after irradiation, which is not conducive to subsequent microscopic analysis, it is not conducive to the rapid screening of a large number of new zirconium alloys, and the development cycle of high-performance new zirconium alloys has been extended.

[0047] Ion irradiation has the advantages of single and stable energy, low experimental cost, short cycle, and basically no radioactivity, because its initial process of producing atomic displacement is very similar to neutron irradiation. In particular, heavy ion implanters that realize full-element periodic self-ion irradiation can not only avoid introducing other impurity elements and thus be as close to neutron irradiation as possible, but can also be used in conjunction with transmission electron microscopy to observe in situ the changes of irradiation defects in samples with irradiation dose. It is considered to be an important means for studying the mechanism of material irradiation damage and preliminary screening of new reactor materials. 2+ The penetration depth in zirconium alloys is very shallow (300 keV Zr 2+ The incident depth in the zirconium alloy cladding is only 92nm), therefore, the preparation of TEM samples is the most core link in the TEM characterization process of zirconium alloy samples after self-ion irradiation.

[0048] The traditional method is as follows: first, a heavy ion implanter is used to implant the zirconium alloy sheet prepared in advance. 2+Ion irradiation is performed, and then the irradiated surfaces of two ion-irradiated zirconium alloy sheets are bonded and compacted with glue. After the glue solidifies, the cross-section of the bonded zirconium alloy sheet is mechanically thinned (until the thickness is less than 100 μm) and a disc with a diameter of 3 mm is made with the bonding area as the center. The Φ3 mm disc is then double-sprayed with pits and electrolysis to obtain a transmission electron microscope sample with a thin area of ​​irradiation damage, which is then observed and analyzed.

[0049] As mentioned above, the traditional method of preparing zirconium alloy TEM samples after self-ion irradiation is very complicated, cumbersome, and time-consuming, and can only achieve the preparation of zirconium alloy cross-section TEM samples after self-ion irradiation. 2+ The ion penetration depth and irradiation damage layer in zirconium alloy are too small to observe the formation of <c>In order to observe large defects such as type dislocations, it is necessary to prepare a thin area of ​​the irradiated surface for transmission electron microscopy observation. However, there is no report on the preparation method of transmission electron microscopy samples of zirconium alloy irradiated surface after self-ion irradiation. In view of the above situation, it is necessary to propose a method for preparing transmission electron microscopy samples of zirconium alloy irradiated surface after self-ion irradiation with high efficiency and good effect.

[0050] Embodiment 1

[0051] A method for preparing zirconium alloy transmission electron microscope samples based on self-ion irradiation, comprising:

[0052] In the first step, a zirconium alloy metal sheet is prepared by mechanical thinning, and the zirconium alloy metal sheet has a first side surface and a second side surface; in this embodiment, the first side surface and the second side surface are only used for distinction, and in practice, one side surface of the metal sheet can be arbitrarily selected as the first side surface and the other side surface can be arbitrarily selected as the second side surface. In addition, according to the requirements of the conventional method, the zirconium alloy metal sheet is set as a zirconium alloy disc, the diameter of the zirconium alloy disc is 3 mm, and the thickness of the zirconium alloy disc is 80 μm to 100 μm.

[0053] In the second step, the first side of the zirconium alloy metal sheet is pre-thinned by using an ion thinning instrument, and a pit is formed on the first side. The pit in this embodiment is as follows: Figure 2 The arc-shaped groove shown has a central axis that coincides with the central axis of the zirconium alloy disc. The pre-thinning voltage of the ion thinning instrument is 5KV, the thinning temperature is -20°C, and the thinning time is 1h.

[0054] The third step is to use a heavy ion implanter to irradiate the zirconium alloy metal sheet with heavy ions, and the heavy ion implantation direction is perpendicular to the first side surface of the zirconium alloy metal sheet; the energy of the heavy ion implanter is 150 keV.

[0055] In the fourth step, the first side of the zirconium alloy metal sheet is protected, and the second side of the zirconium alloy metal sheet is electrolytically double-sprayed to reduce the thickness; the final structure is as follows: Figure 3 As shown, the first side of the zirconium alloy metal sheet is protected by a polytetrafluoroethylene film; the composition of the double spray liquid used in the electrolytic double spray thinning is: 30ml perchloric acid + 170ml n-butanol + 300ml methanol; the temperature of the electrolytic double spray thinning is -30°C.

[0056] The fifth step is to perform transmission electron microscopy analysis on the thinned zirconium alloy metal sheet. If the requirements are met, it is determined that the zirconium alloy transmission electron microscopy sample is successfully prepared.

[0057] Embodiment 2

[0058] This embodiment provides a specific implementation method for the first embodiment, a method for preparing a zirconium alloy transmission electron microscope sample based on self-ion irradiation, comprising:

[0059] In the first step, mechanical thinning methods such as electric spark wire cutting, sandpaper grinding and mechanical polishing are used to prepare zirconium alloy sheets with uniform thickness and smooth surface, with a thickness of 80μm to 100μm, and then a number of zirconium alloy discs with a diameter of 3mm are removed from the zirconium alloy sheet by a punching machine.

[0060] In the second step, the ion gun of the ion thinning instrument is centered on the zirconium alloy disc, and the ion gun is controlled to pre-thin the first side of the zirconium alloy disc; during the thinning process, the centering of the ion gun is adjusted so that the ion gun always thins the central area of ​​the disc at a small angle (the deflection angle of the ion gun of the ion thinning instrument relative to the central axis of the zirconium alloy disc is -5° to +5°), thereby obtaining a zirconium alloy disc sample with a pit on the first side, such as Figure 2 As shown in the figure, the pre-thinning voltage of the ion thinning instrument is 5KV, the thinning temperature is -20℃, and the thinning time is 1h.

[0061] The third step is to load a high-purity zirconium target into the heavy ion implanter, set the irradiation parameters of the heavy ion implanter, such as current, discharge voltage, inert gas beam and irradiation temperature, and perform Zr on the first side of the pre-thinned zirconium alloy wafer. 2+ Ion irradiation, with the first side facing Zr 2+ The incident direction of the ions is used to obtain the irradiated zirconium alloy disc with the expected injection amount; the energy of the heavy ion implanter is 150keV.

[0062] Step 4: Protect the first side of the zirconium alloy disc with a polytetrafluoroethylene film;

[0063] Add electrolytic double-spray solution and an appropriate amount of liquid nitrogen into the electrolytic double-spray instrument, adjust the electrolytic double-spray test parameters such as voltage, beam size, temperature, and transmittance, and perform electrolytic double-spray thinning on the second side of the zirconium alloy disc; Figure 3 As shown, when the transmittance reaches the set value, the electrolytic double spray solution on the zirconium alloy disc is removed. The volume ratio of the double spray liquid used in the electrolytic double spray thinning is: perchloric acid: n-butanol: methanol = 3:17:30; the temperature of the electrolytic double spray thinning is -30°C.

[0064] The fifth step is to perform transmission electron microscopy analysis on the thinned zirconium alloy disc to observe the irradiation microscopic defects in the zirconium alloy disc. If they can be clearly observed, it is judged that the zirconium alloy transmission electron microscopy sample is successfully prepared.

[0065] The acid solution can be removed in a variety of ways. The following is a cleaning implementation method for removing the electrolytic double-spray solution on the zirconium alloy disc, which includes: cleaning the zirconium alloy disc in multiple cups of anhydrous ethanol in turn to remove the electrolytic double-spray solution remaining on the surface of the sample.

[0066] In the description of this specification, the description with reference to the terms "one embodiment / method", "some embodiments / methods", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment / method or example are included in at least one embodiment / method or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / method or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments / methods or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments / methods or examples described in this specification and the features of the different embodiments / methods or examples, without contradiction.

[0067] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0068] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above invention, and these changes or modifications are still within the scope of the present invention.< / c>

Claims

1. A method for preparing zirconium alloy transmission electron microscope samples, characterized in that: include: A zirconium alloy sheet is prepared by a mechanical thinning method, and then a plurality of zirconium alloy discs are removed from the zirconium alloy sheet by a punching machine, wherein the zirconium alloy disc has a first side surface and a second side surface; the diameter of the zirconium alloy disc is 3 mm, and the thickness of the zirconium alloy disc is 80 μm to 100 μm; Aligning an ion gun of an ion thinning instrument to the zirconium alloy wafer, controlling the ion gun to pre-thinn a first side of the zirconium alloy wafer, and forming a pit on the first side; A high-purity zirconium target is loaded in a heavy ion implanter, and the first side of the pre-thinned zirconium alloy disc is irradiated with Zr2+ ions, and the heavy ion implantation direction is perpendicular to the first side of the zirconium alloy disc, to obtain an irradiated zirconium alloy disc with a desired injection amount; A polytetrafluoroethylene film is used to protect the first side of the zirconium alloy disc; Adding electrolytic double-spray solution into the electrolytic double-spray instrument, and performing electrolytic double-spray thinning on the second side of the zirconium alloy disc; when the transmittance reaches a set value, removing the electrolytic double-spray solution on the zirconium alloy disc; Perform transmission electron microscopy analysis on the thinned zirconium alloy disc to observe the irradiation microscopic defects in the zirconium alloy disc. If the defects can be clearly observed, it is judged that the zirconium alloy transmission electron microscopy sample is successfully prepared. The pre-thinning voltage of the ion thinning instrument is 5KV, the thinning temperature is -20°C, the thinning time is 1h, and the deflection angle of the ion gun of the ion thinning instrument relative to the central axis of the zirconium alloy disc is -5°~+5°; The energy of the heavy ion implanter is 150keV; The volume ratio of the components of the double spray liquid used in the electrolytic double spray thinning is: perchloric acid: n-butanol: methanol = 3:17:30; the temperature of the electrolytic double spray thinning is -30°C.

2. The method for preparing a zirconium alloy transmission electron microscope sample according to claim 1, characterized in that: The method for removing the electrolytic double-spray solution on the zirconium alloy disc comprises: cleaning the zirconium alloy disc in multiple cups of anhydrous ethanol in turn to remove the electrolytic double-spray solution remaining on the surface of the sample.

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