CN117433869A - Electrochemical corrosive agent presenting nanometer second phase in zirconium alloy and corrosion method - Google Patents
Electrochemical corrosive agent presenting nanometer second phase in zirconium alloy and corrosion method Download PDFInfo
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- 229910001093 Zr alloy Inorganic materials 0.000 title claims abstract description 65
- 238000005260 corrosion Methods 0.000 title claims abstract description 51
- 230000007797 corrosion Effects 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000003518 caustics Substances 0.000 title claims description 24
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 41
- 238000005498 polishing Methods 0.000 claims abstract description 38
- 239000008367 deionised water Substances 0.000 claims abstract description 19
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 19
- 239000010935 stainless steel Substances 0.000 claims abstract description 9
- 229910001220 stainless steel Inorganic materials 0.000 claims abstract description 9
- 238000005530 etching Methods 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims abstract description 7
- 238000006056 electrooxidation reaction Methods 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 5
- 238000002791 soaking Methods 0.000 claims abstract description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 6
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 5
- 230000000694 effects Effects 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 238000005303 weighing Methods 0.000 claims description 5
- 244000137852 Petrea volubilis Species 0.000 claims description 2
- 239000004744 fabric Substances 0.000 claims description 2
- 238000000227 grinding Methods 0.000 claims description 2
- 238000005406 washing Methods 0.000 claims description 2
- 238000002360 preparation method Methods 0.000 abstract description 7
- 238000004445 quantitative analysis Methods 0.000 abstract description 5
- 230000003670 easy-to-clean Effects 0.000 abstract description 2
- 239000000523 sample Substances 0.000 description 35
- 239000000956 alloy Substances 0.000 description 24
- 229910045601 alloy Inorganic materials 0.000 description 23
- 238000009826 distribution Methods 0.000 description 17
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 13
- 239000000843 powder Substances 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 235000019441 ethanol Nutrition 0.000 description 6
- 239000011521 glass Substances 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 5
- 238000005253 cladding Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 239000010963 304 stainless steel Substances 0.000 description 3
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 3
- 239000010406 cathode material Substances 0.000 description 3
- 238000004140 cleaning Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000003486 chemical etching Methods 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000003758 nuclear fuel Substances 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 150000003754 zirconium Chemical class 0.000 description 2
- 229910000927 Ge alloy Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000001887 electron backscatter diffraction Methods 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000000930 thermomechanical effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000004627 transmission electron microscopy Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/32—Polishing; Etching
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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Abstract
An electrochemical etchant and etching method for presenting a nano second phase in a zirconium alloy, comprising the steps of: selecting a zirconium alloy block sample; the surface of the zirconium alloy is observed, and coarse polishing and fine polishing are sequentially carried out by using a mechanical polishing machine; the method comprises the steps of (1) using a metallographic electrolytic corrosive prepared by mixing sodium hydroxide and deionized water, selecting the surface of a polished sample as an anode, using a stainless steel material as a cathode, putting a polished zirconium alloy sample into the metallographic electrolytic corrosive, and keeping the polished surface opposite to the stainless steel material; and (3) soaking the corroded sample, and finally observing the nano precipitated phase on the surface of the zirconium alloy under a scanning electron microscope to obtain the sample. The invention has the advantages that: the preparation method is simple and convenient to operate; the method is safe and efficient, is not limited by experimental conditions, and has more controllable electrochemical corrosion speed; the structure is easy to clean, no corrosion or non-uniform corrosion phenomenon exists, and meanwhile, the occurrence of pitting corrosion is reduced, so that the follow-up accurate quantitative analysis of the second phase is facilitated.
Description
Technical Field
The invention relates to the field of detection and analysis of nano precipitated phases in zirconium alloy, in particular to an electrochemical corrosive agent presenting a nano second phase in zirconium alloy and a corrosion method.
Background
The zirconium alloy has excellent processability, excellent corrosion resistance in high-temperature high-pressure water and steam at 300-400 ℃, neutron irradiation resistance in a reactor and moderate mechanical properties, so that the zirconium alloy is widely used for manufacturing key components such as fuel cladding tubes, pressure tubes, container tubes, duct tubes, guide tubes, spacer grids, end plugs and the like of water-cooled reactors. With the improvement of the requirements of nuclear reactor burnup and safety, the development of high-performance nuclear fuel assemblies becomes a necessary way for reducing nuclear power cost, wherein the improvement of the water-side corrosion resistance of the nuclear fuel element cladding zirconium alloy is an important technical route.
In order to improve the reliability and service life of the fuel cladding, researchers in various countries mostly adopt a method for optimizing alloy components or improving a processing heat treatment process to obtain the zirconium alloy with more excellent comprehensive performance. A large number of in-pile external experiments and in-pile operation experience prove that the corrosion resistance of the zirconium alloy can be improved to different degrees by adding trace (less than 0.5 wt.%) Sn, fe, cr, nb and other alloy elements. However, most alloying elements other than Sn have low solid solubility in alpha-Zr, and usually the excess elements precipitate out as a second phase in the zirconium alloy. Researches show that the morphology, size, distribution, crystal structure and the like of the second phase can change along with the changes of alloy components, processing deformation technology and heat treatment system, so that the mechanical property, high-temperature water corrosion resistance, creep property, irradiation resistance and the like of the alloy are obviously influenced. Therefore, researches on the crystal structure, the composition of components, the transformation rule and the tissue evolution and distribution characteristics of the second phase in the zirconium alloy in the thermomechanical processing process are all the key points of the research field of zirconium alloy materials, and are one of the source power for promoting the research and development of high-performance zirconium alloy. The method has important guiding significance for researching and analyzing the morphology, the size and the distribution characteristics of the second phase and for designing the components of the zirconium alloy, the safe service of the zirconium alloy in a reactor and the like.
Due to the size limitation of the second phase, related researchers have conducted related studies on nano second phases in zirconium alloys mainly using transmission electron microscopy. However, the transmission electron microscope sample preparation process is very complicated, so that the technical requirement on operators is high, and more importantly, due to the limitation of the transmission electron microscope technology observation, a large amount of relevant experimental observation is needed to be carried out in order to obtain the macroscopic distribution characteristics of the second phase in the zirconium alloy. With the development and progress of electron microscopy, the resolution of related equipment is improved greatly, and under the action of an EBSD probe, the existing high-precision scanning electron microscope can realize component analysis, phase identification and the like of phases with the wavelength of about 5 nm. However, since the second phase in the zirconium alloy is very fine in size (typically between 50-200 nm), how to obtain a bulk sample with a clear appearance of the second phase is one of the problems to be solved in the current state. Currently, the common methods mainly comprise two methods of chemical etching and electrochemical etching. Among them, the chemical etching method is simple and quick to operate, but the etching speed is difficult to control (the technology disclosed in patent CN109060857 a); the electrochemical corrosion rule has proved to be a method for effectively solving the problem of nano precipitated phase presentation on the surface of the bulk zirconium alloy (the technology disclosed in patent CN 109459455A), however, the method needs a mixed electrolytic corrosive agent of perchloric acid and ethanol with high oxidability, and the operation danger is increased; in addition, since perchloric acid has a relatively good conductivity, it is necessary to reduce the temperature of the electrochemical etchant below a threshold temperature (typically around-80 ℃) using a large amount of liquid nitrogen in order to control the electrochemical etching rate, which is difficult to achieve in some factories and limited laboratory conditions, and also increases experimental costs between intangibles. Therefore, if a proper corrosive agent and a corrosion method can be found, a method for presenting nano precipitated phases in the blocky zirconium alloy at room temperature or near room temperature can be realized, and the method can certainly play an important role in promoting the related research and alloy optimization of the zirconium alloy.
Disclosure of Invention
The invention aims to provide an electrochemical corrosive agent for presenting a nanometer second phase in a zirconium alloy and a corrosion method, which are used for solving the problem of inaccurate quantitative analysis caused by severe corrosion experimental conditions, difficult corrosion process control and the like of the second phase of the zirconium alloy in the prior art. In order to achieve the above object, the present invention provides an electrochemical etchant exhibiting nano precipitated phases of zirconium alloy, which is composed of a metallographic electrochemical etchant composed of a mixed aqueous solution of NaOH and KOH and a surface cleaner composed of an absolute ethanol solution and deionized water. When the electrochemical corrosive is adopted for corrosion, ultralow temperature treatment of the corrosive by liquid nitrogen is not needed, and the presentation of the nano precipitated phase of the zirconium alloy can be realized at room temperature or near room temperature, so that the experimental cost is reduced, and the experimental condition limit of the corrosion of the second phase of the zirconium alloy is greatly reduced.
In order to solve the technical problems, the invention provides an electrochemical corrosive agent presenting a nanometer second phase in zirconium alloy and a corrosion method, which are characterized in that: the method comprises the following steps:
step 1, selecting a zirconium alloy block sample, sequentially polishing an interested plane of the zirconium alloy sample by using coarse-to-fine-mesh water abrasive paper, and polishing other surfaces by using coarse abrasive paper to remove a surface oxide layer;
step 2, performing rough polishing and fine polishing on the zirconium alloy observation surface polished in the step 1 in sequence by using a mechanical polishing machine, further removing tiny grinding marks remained by sand paper polishing, and enabling a sample to achieve a bright mirror surface effect;
step 3, preparing a metallographic electrolytic corrosive agent of 1 g/L-5 g/L by mixing sodium hydroxide and deionized water, selecting the surface of the sample polished in the step 2 as an anode, taking a stainless steel material as a cathode, putting a polished zirconium alloy sample into the metallographic corrosive agent, keeping a polished surface facing the stainless steel material, keeping the distance between the polished surface and the polished surface to be 0.5-2 cm, and carrying out electrolytic corrosion for 30-120 seconds by introducing direct current and voltage under the condition of room temperature by adopting a direct current power supply;
and 4, immediately soaking the sample corroded in the step 3 in absolute ethyl alcohol and deionized water for 2-5 minutes, washing the surface of the sample with absolute ethyl alcohol, drying with a blower, and finally observing the nano precipitated phase on the surface of the zirconium alloy under a scanning electron microscope.
In step 1, the number of the abrasive paper for polishing each surface of the zirconium alloy sample is 150#, 320#, 600#, 800# and 2000# abrasive paper in sequence.
In the step 2, short velvet polishing cloth is used for rough polishing and fine polishing, and the polishing solution is SiO 2 The rotation number of the polishing disc in rough polishing is 400 rpm, and the rotation number in fine polishing is 250 rpm.
In the step 3, the method for preparing 2g/L electrolytic corrosive by mixing NaOH and deionized water comprises weighing NaOH with a mass of 1g, and adding into 500ml deionized water for continuous stirring; the voltage of the observed surface of the electrolytic corrosion zirconium alloy is 2-10V, the current density is 0.01-0.1A/cm < 2 >, and the electrochemical corrosion time is 30-60 seconds.
According to the invention, the nano precipitated phase in the zirconium alloy is accurately and clearly presented in a more efficient and safer way under the conditions of room temperature and one-time liquid preparation by utilizing stronger corrosion resistance of the zirconium alloy nano precipitated phase compared with a matrix and potential difference of the zirconium alloy nano precipitated phase and the matrix in the electrochemical corrosion process and by setting low corrosion current, so that the crystal structure, morphology, components and distribution characteristics of a second phase are obtained by quantitative analysis through a scanning electron microscope, and the guiding optimization of a material post-treatment mode is realized.
Compared with the prior art, the invention has the advantages that:
the electrochemical corrosive agent presenting the nano precipitated phase in the zirconium alloy and the corrosion method thereof have the following advantages: the adopted reagents are all conventional chemical reagents, and the preparation method is simple and convenient to operate; compared with the traditional technical method, the method is safer and more efficient, is not limited by experimental conditions, does not need to use liquid nitrogen and the like to treat electrolytic corrosive agents at ultralow temperature, and can present nano precipitated phases in the zirconium alloy at room temperature or near room temperature; the conditions of nanometer precipitated phases in different zirconium alloys can be accurately and efficiently obtained by preparing NaOH electrochemical corrosive agents with different concentrations at one time, the use of perchloric acid which is high in conductivity and high in oxidation property is avoided, and the electrochemical corrosion speed is more controllable; the zirconium alloy precipitated phase boundary corroded by the method is obvious, the structure is easy to clean, no corrosion or non-uniform corrosion phenomenon exists, the occurrence of pitting corrosion is reduced, and the follow-up accurate quantitative analysis of the second phase is facilitated.
Drawings
The invention will be described in further detail with reference to the accompanying drawings and embodiments:
FIG. 1 is a graph showing the morphology and EDS distribution of nano precipitated phases in the Zr-4 alloy in example 1;
FIG. 2 is a graph showing the morphology and EDS distribution of a second phase of the wrought Ge-doped modified Zr-4 alloy of example 2;
FIG. 3 is a quantitative analysis result of a second phase element of the wrought Ge element-added modified Zr-4 alloy in example 2;
FIG. 4 is a graph showing the morphology of the second phase of the Zircaloy-2 alloy of example 2 and its distribution.
Detailed Description
The present invention will be further explained with reference to specific embodiments, but the structure, proportion, size, etc. shown in the drawings are only used for understanding and reading by those skilled in the art, and are not intended to limit the applicable limitations of the present invention, so that any structural modification, proportional relation change or size adjustment does not have any technical significance, and all fall within the scope of the technical contents disclosed in the present invention without affecting the efficacy and achievement of the present invention.
Example 1:
the Zr-1.5Sn-0.2Fe-0.1Cr (wt.%) alloy is a Zr-Sn series zirconium alloy with excellent comprehensive service performance in the current nuclear reactor. The matrix phase of the Zr-4 alloy is an alpha-Zr phase with a close-packed hexagonal structure, the common second phase morphology in the alloy is mainly spherical or elliptic, the second phase size is about 50-200nm, the nano precipitated phase in the solid solution state Zr-4 zirconium alloy is researched by adopting the method, and the specific implementation steps are as follows:
(1) Preparing an electrolytic corrosive agent: firstly, measuring 500ml of deionized water by using a measuring cylinder, placing the deionized water in a glass beaker, then weighing 1g of sodium hydroxide powder by using a balance, adding the sodium hydroxide powder into the beaker, stirring by using a glass rod to enable the sodium hydroxide powder to be completely dissolved in water, and preparing to obtain an electrochemical corrosive agent;
(2) Sample preparation: after the electrolytic polishing solution is prepared, sequentially polishing Zr-4 alloy to be corroded by 150# water abrasive paper, 320# water abrasive paper, 800# water abrasive paper and 2000# water abrasive paper, and then using nano SiO 2 Mechanically polishing the polished surface until the polished surface shows a mirror surface effect, cleaning the sample with water and alcohol in sequence, and drying for later use;
(3) Electrolytic corrosion process: pouring the electrolytic corrosion solution prepared in the step (1) into an electrolytic corrosion instrument, wherein the cathode material of the electrolytic corrosion instrument is 304 stainless steel sheet, and connecting the polished Zr-4 alloy sample to the positive electrode of a direct current power supply. The polished observation surface of the sample is opposite to the stainless steel sheet, the sample and the iron sheet are kept to be placed in parallel into electrolytic corrosive agent, the distance between the sample and the iron sheet is 1cm, and 5V direct current voltage is introduced to carry out electrolytic corrosion for 60 seconds.
(4) And (5) subsequent treatment and observation: when electrolytic corrosion was completed, the power was turned off immediately, and the samples were taken out, immersed in 100ml of absolute ethanol and 100ml of deionized water, respectively, for 2 minutes, and then washed with alcohol and dried. The sample after electrolytic corrosion by the invention is observed by a scanning electron microscope, and the macroscopic distribution of the second phase and the distribution diagram of the element surface are shown in figure 1. The black contrast circular or elliptical areas in the figure are specific distribution positions of the second phase, and the areas show obvious element enrichment.
Example 2:
in this example, wrought Zr-4-0.4wt.% Ge alloy was used, with a nominal composition of Zr-1.5Sn-0.2Fe-0.1Cr-0.4Ge (wt%). The alloy is a novel zirconium alloy developed for improving the corrosion resistance of Zr-4 alloy. In order to obtain the structural characteristics of the novel Ge element added modified zirconium alloy, the second phase morphology, distribution and other characteristics of the novel Ge element added modified zirconium alloy need to be studied. In this example, the electrolytic corrosion process for the second phase of as-cast Zr-4-0.4wt.% Ge zirconium alloy is specifically as follows:
(1) Preparing an electrolytic corrosive agent: firstly, measuring 500ml of deionized water by using a measuring cylinder, placing the deionized water in a glass beaker, then weighing 2g of sodium hydroxide powder by using a balance, adding the sodium hydroxide powder into the beaker, stirring by using a glass rod to enable the sodium hydroxide powder to be completely dissolved in water, and preparing to obtain an electrochemical corrosive agent;
(2) Sample preparation: after the electrolytic polishing solution is prepared, sequentially polishing Zr-4 alloy to be corroded by 150# water abrasive paper, 320# water abrasive paper, 800# water abrasive paper and 2000# water abrasive paper, and then using nano SiO 2 Mechanically polishing the polished surface until the polished surface shows a mirror surface effect, cleaning the sample with water and alcohol in sequence, and drying for later use;
(3) Electrolytic corrosion process: pouring the electrolytic corrosion solution prepared in the step (1) into an electrolytic corrosion instrument, wherein the cathode material of the electrolytic corrosion instrument is 304 stainless steel sheet, and connecting the polished Zr-4 alloy sample to the positive electrode of a direct current power supply. The polished observation surface of the sample is opposite to the stainless steel sheet, the sample and the iron sheet are kept to be placed in parallel into electrolytic corrosive agent, the distance between the sample and the iron sheet is 0.5cm, and 2V direct current voltage is introduced to carry out electrolytic corrosion for 60 seconds.
(4) And (5) subsequent treatment and observation: when electrolytic corrosion was completed, the power was turned off immediately, and the samples were taken out, immersed in 100ml of absolute ethanol and 100ml of deionized water, respectively, for 3 minutes, and then washed with alcohol and dried. The sample after electrolytic corrosion by the invention is observed by a scanning electron microscope, and the macroscopic distribution of the second phase and the distribution diagram of the element surface are shown in figure 2. The black contrast circular or elliptical areas in the figure are specific distribution positions of the second phase, and the areas show obvious element enrichment.
Example 3:
in this example, zircaloy-2 was used, which had a nominal composition of Zr-1.5Sn-0.1Fe-0.1Cr-0.05Ni (wt%). The alloy is a commercial zirconium alloy and is mainly applied to the field of nuclear reactor cladding. In this example, the electrolytic corrosion process of the second phase of the Zircaloy-2 alloy is specifically as follows:
(1) Preparing an electrolytic corrosive agent: firstly, measuring 500ml of deionized water by using a measuring cylinder, placing the deionized water in a glass beaker, then weighing 3g of sodium hydroxide powder by using a balance, adding the sodium hydroxide powder into the beaker, stirring by using a glass rod to enable the sodium hydroxide powder to be completely dissolved in water, and preparing to obtain an electrochemical corrosive agent;
(2) Sample preparation: after the electrolytic polishing solution is prepared, sequentially polishing Zr-2 alloy to be corroded by 150# water abrasive paper, 320# water abrasive paper, 800# water abrasive paper and 2000# water abrasive paper, and then using nano SiO 2 Mechanically polishing the polished surface until the polished surface shows a mirror surface effect, cleaning the sample with water and alcohol in sequence, and drying for later use;
(3) Electrolytic corrosion process: pouring the electrolytic corrosion solution prepared in the step (1) into an electrolytic corrosion instrument, wherein the cathode material of the electrolytic corrosion instrument is 304 stainless steel sheet, and connecting the polished Zr-4 alloy sample to the positive electrode of a direct current power supply. The polished observation surface of the sample is opposite to the stainless steel sheet, the sample and the iron sheet are kept to be placed in parallel into electrolytic corrosive agent, the distance between the sample and the iron sheet is 1cm, and 3V direct current voltage is introduced to carry out electrolytic corrosion for 60 seconds.
(4) And (5) subsequent treatment and observation: immediately taking down the sample after corrosion, sequentially placing the sample into 50ml of absolute ethyl alcohol and deionized water, soaking for 2min to clean the sample, and drying. A scanning electron microscope is adopted to observe a corroded Zr-2 zirconium alloy sample, the secondary electron morphology of the second phase distribution and the element surface distribution diagram of response are shown as shown in fig. 4, a circular or elliptical area with dark contrast in the diagram is a specific position of the second phase in the alloy, and obvious enrichment of Fe element can be seen in the area where the second phase is located.
The invention is not a matter of the known technology.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (4)
1. An electrochemical corrosive agent and a corrosion method for presenting a nanometer second phase in zirconium alloy are characterized in that: the method comprises the following steps:
step 1, selecting a zirconium alloy block sample, sequentially polishing an interested plane of the zirconium alloy sample by using coarse-to-fine-mesh water abrasive paper, and polishing other surfaces by using coarse abrasive paper to remove a surface oxide layer;
step 2, performing rough polishing and fine polishing on the zirconium alloy observation surface polished in the step 1 in sequence by using a mechanical polishing machine, further removing tiny grinding marks remained by sand paper polishing, and enabling a sample to achieve a bright mirror surface effect;
step 3, preparing a metallographic electrolytic corrosive agent of 1 g/L-5 g/L by mixing sodium hydroxide and deionized water, selecting the surface of the sample polished in the step 2 as an anode, taking a stainless steel material as a cathode, putting a polished zirconium alloy sample into the metallographic corrosive agent, keeping a polished surface facing the stainless steel material, keeping the distance between the polished surface and the polished surface to be 0.5-2 cm, and carrying out electrolytic corrosion for 30-120 seconds by introducing direct current and voltage under the condition of room temperature by adopting a direct current power supply;
and 4, immediately soaking the sample corroded in the step 3 in absolute ethyl alcohol and deionized water for 2-5 minutes, washing the surface of the sample with absolute ethyl alcohol, drying with a blower, and finally observing the nano precipitated phase on the surface of the zirconium alloy under a scanning electron microscope.
2. The electrochemical etchant and etching method for presenting a nano second phase in a zirconium alloy according to claim 1, wherein:
in step 1, the number of the abrasive paper for polishing each surface of the zirconium alloy sample is 150#, 320#, 600#, 800# and 2000# abrasive paper in sequence.
3. The electrochemical etchant and etching method for presenting a nano second phase in a zirconium alloy according to claim 1, wherein:
in the step 2, short piles are used for rough polishing and fine polishingPolishing cloth, wherein the polishing solution is SiO 2 The rotation number of the polishing disc in rough polishing is 400 rpm, and the rotation number in fine polishing is 250 rpm.
4. The electrochemical etchant and etching method for presenting a nano second phase in a zirconium alloy according to claim 1, wherein:
in the step 3, the method for preparing 2g/L electrolytic corrosive by mixing NaOH and deionized water comprises weighing NaOH with a mass of 1g, and adding into 500ml deionized water for continuous stirring; the voltage of the observed surface of the electrolytic corrosion zirconium alloy is 2-10V, the current density is 0.01-0.1A/cm < 2 >, and the electrochemical corrosion time is 30-60 seconds.
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| CN202311359767.9A CN117433869A (en) | 2023-10-20 | 2023-10-20 | Electrochemical corrosive agent presenting nanometer second phase in zirconium alloy and corrosion method |
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| CN202311359767.9A CN117433869A (en) | 2023-10-20 | 2023-10-20 | Electrochemical corrosive agent presenting nanometer second phase in zirconium alloy and corrosion method |
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