Metal material electrolytic polishing solution, preparation method and EBSD sample preparation method

Abstract

The invention discloses a metal material electrolytic polishing solution, a preparation method and an EBSD sample preparation method, the electrolytic polishing solution comprises the following components in percentage by volume: 15-30% of acid substance containing sulfuric acid and hydrochloric acid, 60-80% of alcohol substance containing methanol and ethanol, and the balance of water, and the volume percentage of the acid substance is 15-30%, and the volume percentage of the alcohol substance is 60-80%. And the balance of water. The electrolytic polishing solution is easy to prepare, low in cost, easy to store, capable of being repeatedly used for a long time, suitable for preparation of EBSD samples of various metal materials, capable of achieving rapid electrolytic polishing at the room temperature without parameter debugging, high in sample preparation efficiency and test repeatability and high in calibration rate.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy material surface treatment, and in particular relates to a metal material electrolytic polishing liquid, a preparation method and an EBSD sample preparation method. Background Art

[0002] Electron Back Scatter Diffraction (EBSD) technology can achieve quantitative characterization of microstructures from millimeter to nanometer scale in a scanning electron microscope. It can be used to determine crystal structure and orientation, characterize grain boundaries and phase boundaries, distinguish phases of different crystal structures, and provide information about local crystal integrity. It lays the foundation for rapid and efficient quantitative statistical research on the microstructure of materials. It has become an indispensable means in the field of material characterization and has a wide range of applications in the research of materials such as metals, semiconductors, minerals and ceramics.

[0003] EBSD technology collects backscattered electrons in a 10-50nm thick area under the surface of the sample for imaging, so sample preparation is a key step in order to obtain high-quality EBSD data and information. EBSD sample preparation usually requires that the sample test surface is smooth and flat, and the contamination on the sample surface and defects such as residual stress layer and oxide layer caused by external factors need to be removed. At present, the commonly used methods for preparing EBSD samples of metal materials mainly include vibration polishing, electrolytic polishing, ion polishing, etc. The principle of vibration polishing is to rely on oscillation to allow the sample surface to be ground and polished by polishing liquid. It has a wide range of applications, but can only remove a small amount of deformation left over from mechanical polishing. The sample surface is prone to stress and mechanical damage. At the same time, it depends on the selection of polishing cloth, polishing liquid, and the load and time control of vibration polishing. The principle of ion thinning is to bombard the sample surface with a high-energy ion beam under vacuum conditions to remove the surface stress layer. It is applicable to most materials and has a good polishing effect, but it is expensive and inefficient, and requires appropriate voltage and angle parameters. Compared with the above two methods, electrolytic polishing relies on electrochemical action to remove the strain layer on the sample surface. It has the advantages of simple operation, fast speed, low cost, and the ability to prepare larger samples as needed. It is currently the most widely used method for preparing EBSD samples of metal materials.

[0004] The factors that affect the electropolishing effect mainly include the composition of the electropolishing solution and the electropolishing parameters. At present, different electropolishing solutions and electropolishing parameters (current density, voltage, electrolyte temperature, polishing time, etc.) are usually required for the preparation of EBSD samples of different alloys. The exploration of parameters not only increases unnecessary resource investment, but also is not conducive to the application and development of EBSD technology in material research. In order to solve this problem, it is urgent to find a universal method for preparing EBSD samples of metal materials. In the patent invention with publication number CN 109900727 A, an electropolishing solution mixed with perchloric acid and anhydrous ethanol is used to invent a method for preparing EBSD samples of various metal materials of different sizes and compositions, and the electropolishing parameters are consistent and do not require debugging. However, in order to control the polishing rate, liquid nitrogen is required to reduce the temperature of the electropolishing solution to about -120°C before it can be used. The electropolishing efficiency is low. At the same time, perchloric acid is highly corrosive and dangerous, and is not easy to preserve, which poses a great safety hazard. In view of the important value of EBSD analysis and testing technology in the characterization of metal material structure, it is urgent to find a universal, easy-to-operate, efficient, low-hazard, easy-to-store, and stable metal material electrolytic polishing solution and EBSD sample preparation method. Summary of the invention

[0005] In order to overcome the problem of low electrolytic polishing efficiency in the prior art, the present invention aims to provide a metal material electrolytic polishing liquid, a preparation method and an EBSD sample preparation method, which can improve the polishing efficiency, quality and stability of metal material EBSD sample preparation. The electrolytic polishing liquid prepared by the method has low hazard, is easy to store, has good stability and can be reused for a long time, is low in cost and easy to prepare. The corresponding metal material EBSD sample preparation method is not only simple in equipment, strong in practicality, and easy to operate, but also suitable for the preparation of EBSD samples of various metal materials. It does not need to adjust the electrolytic polishing parameters during the preparation process, has high test repeatability, high sample calibration rate, and has good economic benefits and promotion value.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A metal material electrolytic polishing liquid comprises an acid substance containing sulfuric acid and hydrochloric acid, an alcohol substance containing methanol and ethanol, and water. Calculated by volume percentage, the volume percentage of the acid substance is 15-30%, the volume percentage of the alcohol substance is 60-80%, and the balance is water.

[0008] A further improvement of the present invention is that the acid substance is a mixture of any two of phosphoric acid, oxalic acid and acetic acid with sulfuric acid and hydrochloric acid.

[0009] A further improvement of the present invention is that the acid substance is a mixture of sulfuric acid, hydrochloric acid, phosphoric acid and oxalic acid in a volume ratio of 4-6:1-3:1-2:1-2, or a mixture of sulfuric acid, hydrochloric acid, phosphoric acid and acetic acid in a volume ratio of 4-6:1-3:1-2:1-2, or a mixture of sulfuric acid, hydrochloric acid, oxalic acid and acetic acid in a volume ratio of 4-6:1-3:1-2:1-2; the mass concentration of sulfuric acid is 98.3%, the mass concentration of hydrochloric acid is 36-38%, the mass concentration of phosphoric acid is 95%, the mass concentration of oxalic acid is greater than 99.5%, and the mass concentration of acetic acid is 99.8%.

[0010] A further improvement of the present invention is that the alcohol substance is a mixture of any two of ethylene glycol, propylene glycol and n-butanol with methanol or ethanol.

[0011] A further improvement of the present invention is that the alcohol substance is a mixture of methanol, ethanol, ethylene glycol and propylene glycol in a volume ratio of 6-8:2-3:1-2:1-2, or a mixture of methanol, ethanol, ethylene glycol and n-butanol, or a mixture of methanol, ethanol, propylene glycol and n-butanol.

[0012] A method for preparing a metal material electrolytic polishing liquid comprises the following steps:

[0013] After the acid substances containing sulfuric acid and hydrochloric acid are mixed with water, the alcohol substances containing methanol and ethanol are added and stirred evenly to obtain the metal material electrolytic polishing liquid.

[0014] An EBSD sample preparation method comprises the following steps:

[0015] The polished metal material sample preparation surface is used as an anode and the stainless steel plate is used as a cathode, and the electrolytic polishing liquid described in any one of claims 1 to 5 is used for electrolytic polishing;

[0016] A further improvement of the present invention is that the metal material sample preparation surface is W2.5 grain size and above;

[0017] The parameters of electrolytic polishing are: voltage 20-50V, current density 1-5A / cm 2 , time 10-30s.

[0018] A further improvement of the present invention is that the front side of the metal material sample preparation surface is parallel to and directly opposite to the stainless steel plate, and the front side of the metal material sample preparation surface is 4-8 cm away from the stainless steel plate.

[0019] A further improvement of the present invention is that the area ratio of the stainless steel plate to the metal material sample preparation surface is (4-10):1;

[0020] The metal material is nickel-based high-temperature alloy, iron-based high-temperature alloy, cobalt-based high-temperature alloy, austenitic heat-resistant steel, titanium, copper or copper alloy.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The electrolytic polishing liquid provided by the present invention does not contain any other oxidizing acid except sulfuric acid, and the proportion of acids is low, so it is less harmful to human body, easy to store, stable and can be reused for a long time, not easy to age, low in cost and easy to prepare. Taking into account the organizational differences of various metal materials, different types of acids and alcohols are used in synergy, and distilled water is added to increase conductivity, thereby ensuring a suitable polishing speed and improving polishing efficiency.

[0023] The preparation method of the electrolytic polishing liquid provided by the present invention allows the components of the electrolytic polishing liquid to be fully dissolved and evenly mixed by limiting the appropriate mixing sequence, mixing speed and stirring steps. The obtained electrochemical polishing liquid has good stability, is not prone to precipitates when left for a long time, and has a longer service life.

[0024] The present invention is suitable for the preparation of EBSD samples of various metal materials prepared with different components, has little restriction on the shape of the sample, does not need to adjust the electrolytic polishing parameters during the preparation process, has high test repeatability, and has a high sample calibration rate, which can generally reach more than 95%. The present invention is simple to operate, is not limited by the site and equipment, can be operated at room temperature, has good polishing effect, and has high repeatability and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 is an alloy surface morphology image collected by EBSD technology after the Ni-based deformable high-temperature alloy HT700T alloy in Example 1 of the present invention is electrolytically polished;

[0027] Figure 2 is a line roughness measurement curve of the alloy surface along the x direction after electrolytic polishing of the Ni-based deformed high-temperature alloy HT700T alloy in Example 1 of the present invention;

[0028] Figure 3 is an inverse pole figure collected by EBSD technology after the Ni-based deformed high-temperature alloy HT700T alloy in Example 1 of the present invention is subjected to electrolytic polishing;

[0029] Figure 4It is a local orientation difference map collected by EBSD technology after the Fe-based deformed high-temperature alloy HT700R alloy in Example 2 of the present invention is electrolytically polished;

[0030] Figure 5 It is the Kikuchi map collected by EBSD technology after the stainless steel HR3C alloy in Example 3 of the present invention is electrolytically polished;

[0031] Figure 6 The inverse pole figure and the corresponding resolution rate of the cast high-temperature alloy K417G alloy collected by EBSD technology after electrolytic polishing in Example 4 of the present invention;

[0032] Figure 7 is the inverse pole figure and the corresponding resolution rate collected by EBSD technology after the single crystal high temperature alloy PWA 1483 alloy is electropolished in Example 5 of the present invention;

[0033] Figure 8 is the inverse pole figure collected by EBSD technology after the Cu-16at.%Al alloy in Example 6 of the present invention is subjected to electrolytic polishing;

[0034] Fig. 9 1 is a band comparison diagram collected by EBSD technology after electrolytic polishing of pure Ti after large plastic deformation in Example 7 of the present invention; wherein (a) is a band comparison diagram example of α-Ti phase, (b) is a band comparison diagram example of β-Ti phase, and (c) is a band comparison diagram;

[0035] Fig.10 This is an alloy surface morphology image collected by EBSD technology after the Ni-based deformed high-temperature alloy HT700T alloy in Comparative Example 1 of the present invention is electrolytically polished;

[0036] Fig.11 This is a band comparison diagram collected by EBSD technology after the Ni-based deformed high-temperature alloy HT700T alloy in Comparative Example 2 of the present invention is electrolytically polished;

[0037] Fig.12 This is an alloy surface morphology image collected by EBSD technology after the Ni-based deformed high-temperature alloy HT700T alloy in Comparative Example 3 of the present invention is electrolytically polished;

[0038] Fig.13 It is the inverse pole figure collected by EBSD technology after the Ni-based deformed high-temperature alloy HT700T alloy in Comparative Example 4 of the present invention is electrolytically polished. DETAILED DESCRIPTION

[0039] The present invention provides the following embodiments in order to better further understand the present invention, but is not limited to the best implementation mode described, and does not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0040] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0041] The present invention provides a metal material electrolytic polishing liquid, comprising an acid substance, an alcohol substance and distilled water, wherein, in terms of volume percentage, the volume percentage of the acid substance is 15-30%, the volume percentage of the alcohol substance is 60-80%, and the balance is distilled water. Distilled water can increase conductivity.

[0042] The acid substance is a mixture of any two of phosphoric acid, oxalic acid and acetic acid with sulfuric acid and hydrochloric acid, that is, the acid substance is a mixture of sulfuric acid, hydrochloric acid, phosphoric acid and oxalic acid, or a mixture of sulfuric acid, hydrochloric acid, phosphoric acid and acetic acid, or a mixture of sulfuric acid, hydrochloric acid, oxalic acid and acetic acid.

[0043] Among them, the ratio of sulfuric acid, hydrochloric acid, phosphoric acid to oxalic acid, the ratio of sulfuric acid, hydrochloric acid, phosphoric acid to acetic acid, and the ratio of sulfuric acid, hydrochloric acid, oxalic acid to acetic acid are all 4-6:1-3:1-2:1-2.

[0044] The alcohol substance is a mixture of any two of ethylene glycol, glycerol and n-butanol with methanol or ethanol. That is, the alcohol substance is a mixture of methanol, ethanol, ethylene glycol and glycerol, or a mixture of methanol, ethanol, ethylene glycol and n-butanol, or a mixture of methanol, ethanol, glycerol and n-butanol.

[0045] Among them, the ratio of methanol, ethanol, ethylene glycol to propylene glycol, the ratio of methanol, ethanol, ethylene glycol to n-butanol, and the ratio of methanol, ethanol, propylene glycol to n-butanol are all 6-8:2-3:1-2:1-2.

[0046] Optionally, the mass concentration of sulfuric acid is 98.3%, the mass concentration of hydrochloric acid is 36-38%, the mass concentration of phosphoric acid is 95%, the mass concentration of oxalic acid is greater than 99.5%, and the mass concentration of acetic acid is 99.8%.

[0047] Optionally, the mass concentrations of methanol, ethanol, ethylene glycol, glycerol and n-butanol are all greater than 99.5%.

[0048] The present invention provides a method for preparing the metal material electrolytic polishing liquid as described above, comprising the following steps:

[0049] S1, mixing any two of ethylene glycol, propylene glycol and n-butanol with a mixture of methanol and ethanol, and then adding distilled water to obtain component A;

[0050] S2, mixing any two of phosphoric acid, oxalic acid and acetic acid with sulfuric acid and hydrochloric acid to obtain component B;

[0051] S3, slowly add component B into component A using a guide rod, stir evenly, and obtain an electrolytic polishing solution.

[0052] Optionally, in step S3, the electrolytic polishing liquid is stirred to room temperature.

[0053] The present invention provides a method for preparing an electron backscatter diffraction EBSD sample by using the metal material electrolytic polishing liquid as described above, comprising the following steps:

[0054] S1: Mechanically grind and polish the sample surface of the metal material, and rinse and dry it with ethanol;

[0055] Optionally, in step S1, mechanical grinding is performed to a mesh size of 2000 or above, and mechanical polishing is performed using diamond grinding paste to a particle size of W2.5 or above.

[0056] S2: using the sample surface of the metal material after mechanical polishing as the anode and the traditional stainless steel plate as the cathode, and performing electrolytic polishing using the electrolytic polishing solution as described above;

[0057] Optionally, the electrolytic polishing parameters in step S2 are: temperature is room temperature, voltage is 20-50V, current density is 1-5A / cm 2 , time 10-30s.

[0058] S3: The electropolished metal material is quickly taken out and rinsed with water, then ultrasonically cleaned in ethanol and blown dry;

[0059] Optionally, the front side of the metal material sample preparation surface is parallel to and opposite to the stainless steel plate, 4-8 cm away from the stainless steel cathode plate, and the area ratio of the stainless steel cathode plate to the metal material sample preparation surface is (4-10):1.

[0060] Optionally, the electrolytic polishing liquid is stirred by magnetic force, and the magnetic stirring speed is 200-300r / min;

[0061] Optionally, the metal material electrolytic polishing liquid or metal material EBSD preparation method is applicable to a variety of metal materials, especially to nickel-based high-temperature alloys, iron-based high-temperature alloys, cobalt-based high-temperature alloys, austenitic heat-resistant steel, titanium, copper and copper alloys, etc.

[0062] The proportions of the electrolytic polishing solutions of the embodiments of the present invention and the comparative examples are shown in Table 1, and the EBSD preparation parameters of the embodiments of the present invention and the comparative examples are shown in Table 2.

[0063] Table 1 Proportions of electrolytic polishing liquids in the embodiments of the present invention and the comparative examples

[0064]

[0065]

[0066] Table 2 EBSD preparation parameters of electrolytic polishing solution in the embodiments of the present invention and comparative examples

[0067]

[0068]

[0069] Example 1

[0070] This embodiment provides a Ni-based deformed high-temperature alloy HT700T alloy electrolytic polishing liquid and EBSD preparation method and application for high-parameter ultra-supercritical unit boiler tubes, which are specifically as follows:

[0071] First, prepare 400 ml of electrolytic polishing liquid, mix 156.8 ml of methanol, 56 ml of ethanol, 33.6 ml of ethylene glycol, and 33.6 ml of propylene glycol, and then add 30 ml of distilled water to obtain component A; mix 45 ml of sulfuric acid, 22.5 ml of hydrochloric acid, 13.5 ml of phosphoric acid, and 9 ml of oxalic acid to obtain component B; slowly add the mixed component B to component A using a guide rod, and stir until the temperature of the mixed liquid drops to room temperature to obtain an electrolytic polishing liquid. After testing, the pH value of the electrolytic polishing liquid with a circulation time of about 500 hours did not change significantly, and it still had a good electrolytic polishing effect. Therefore, it is believed that the polishing liquid has good stability, is not easy to age, and has a long life (the preparation process and results of other embodiments are similar, and the proportions are shown in Table 1, which will not be repeated).

[0072] The Ni-based deformed high-temperature alloy HT700T alloy specimen (size 2×2×2cm 3 ), the alloy surface was mechanically polished step by step with 200#, 600#, 1200#, and 2000# metallographic sandpaper, and then mechanically polished to W2.5 particle size with diamond grinding paste, and the sample block was impacted with ethanol and blown dry. The cathode of the power supply was connected to the stainless steel plate, and the anode of the power supply was connected to the Ni-based deformed high-temperature alloy HT700T alloy sample block. The front of the sample preparation surface was parallel to the stainless steel cathode plate, and the distance from the stainless steel cathode plate was 6cm. The area ratio of the stainless steel cathode plate to the metal material sample preparation surface was 5:1. The electrolytic polishing temperature was room temperature, the voltage was 25V, and the current density was 2.5A / cm 2, time 20s, magnetic stirring speed 250r / min; the electropolished sample was quickly taken out and rinsed with water, then ultrasonically cleaned in ethanol and dried; (the EBSD sample preparation process of other embodiments is similar, and the specific change parameters are shown in Table 2, which will not be repeated).

[0073] EBSD was used to collect the surface morphology of the sample after electrolytic polishing. The results are as follows: Figure 1 As shown in the figure, the alloy surface is relatively flat and all scratches have been removed. Figure 1 The line roughness of the sample is measured in the direction shown, and the curve is as follows Figure 2 As shown, it can be seen that the surface roughness Ra of the alloy obtained in this embodiment is 0.04 um. Figure 3 This is the inverse pole figure collected by EBSD technology after the sample was electrolytically polished. Its calibration rate is as high as 99%, and the remaining 1% is the zero resolution point at the grain boundary.

[0074] Example 2

[0075] This embodiment provides an electrolytic polishing liquid and EBSD preparation method and application of Fe-based deformed high-temperature alloy HT700R alloy for high-parameter ultra-supercritical unit rotors, which are specifically as follows:

[0076] First, 400 ml of electrolytic polishing solution was prepared, and the proportions and steps are shown in Table 1. The specific parameters of the EBSD sample preparation process are shown in Table 2. Figure 4 This is a local orientation difference map collected by EBSD technology after the sample was electrolytically polished. It can be seen that the electrolytic polishing effect is excellent.

[0077] Example 3

[0078] This embodiment provides an austenitic stainless steel HR3C alloy electrolytic polishing liquid and an EBSD preparation method and application, which are as follows:

[0079] First, 300 ml of electrolytic polishing solution was prepared, and the proportions and steps are shown in Table 1. The specific parameters of the EBSD sample preparation process are shown in Table 2. Figure 5 This is the Kikuchi map of one of the points collected by EBSD technology after the sample was electropolished. It can be seen that the electropolishing effect is excellent, the stress layer is completely removed, and the Kikuchi map is clear.

[0080] Example 4

[0081] This embodiment provides a casting high-temperature alloy K417G alloy electrolytic polishing liquid and EBSD preparation method and application, which are as follows:

[0082] First, 500 ml of electrolytic polishing solution was prepared, and the proportions and steps were shown in Table 1. The specific parameters of the EBSD sample preparation process are shown in Table 2. Figure 6The inverse pole figure and corresponding resolution rate collected by EBSD technology after the sample was electrolytically polished. It can be seen that the calibration rate is as high as 99.89%.

[0083] Example 5

[0084] This embodiment provides a single crystal high temperature alloy PWA 1483 alloy electrolytic polishing solution and EBSD preparation method and application, as follows:

[0085] First, prepare 200 ml of electrolytic polishing solution, and the proportions and steps are shown in Table 1. The specific parameters of the EBSD sample preparation process are shown in Table 2. Figure 7 The inverse pole figure and the corresponding resolution rate collected by EBSD technology after the sample was electrolytically polished. It can be seen that the calibration rate is as high as 100%;

[0086] Example 6

[0087] This embodiment provides a Cu-16at.%Al alloy electrolytic polishing solution and an EBSD preparation method and application, as follows:

[0088] First, prepare 200 ml of electrolytic polishing solution, and the proportions and steps are shown in Table 1. The specific parameters of the EBSD sample preparation process are shown in Table 2. Figure 8 This is the inverse pole figure collected by EBSD technology after the sample was electrolytically polished, which shows that the electrolytic polishing effect is excellent.

[0089] Example 7

[0090] This embodiment provides a pure Ti electrolytic polishing solution after large plastic deformation and an EBSD preparation method and application, as follows:

[0091] First, 400 ml of electrolytic polishing solution was prepared, and the proportions and steps are shown in Table 1. The specific parameters of the EBSD sample preparation process are shown in Table 2. Fig. 9 (a), (b) and (c) are the band comparison diagrams of the α-Ti phase and the β-Ti phase collected by EBSD technology after the sample was electrolytically polished. From the band comparison diagrams, it can be seen that the electrolytic polishing effect is excellent and the two different phases are clearly resolved.

[0092] Comparative Example 1

[0093] This comparative example provides a Ni-based deformed high-temperature alloy HT700T alloy electrolytic polishing liquid and its application. Compared with Example 1, this comparative example is different only in that the acid ratio is too high. The alloy in Example 1 electrolytically corrodes when the same parameters are electrolyzed. The surface morphology of the sample after electrolytic polishing is collected by EBSD. The results are as follows: Fig.10 As shown, the grain boundaries and phases on the alloy surface have been corroded, which is not conducive to EBSD characterization.

[0094] Comparative Example 2

[0095] This comparative example provides a Ni-based deformed high-temperature alloy HT700T alloy electrolytic polishing liquid and its application. Compared with Example 1, this comparative example is different only in that the alcohol ratio is too high and the acid ratio is less. The alloy in Example 1 electrolyzed with the same parameters has a stress layer and scratches that cannot be removed, resulting in a reduced resolution, which is not conducive to EBSD characterization. The results are as follows Fig.11 As shown in the comparison chart.

[0096] Comparative Example 3

[0097] This comparative example provides a Ni-based deformed high-temperature alloy HT700T alloy electrolytic polishing liquid and its application. Compared with Example 1, this comparative example has the same electrolytic polishing liquid, and the only difference is that the increase in voltage in the electrolytic polishing parameters leads to an increase in current density. Even if the time is reduced, electrolytic corrosion is still caused, resulting in a decrease in resolution, which is not conducive to EBSD characterization. The results are as follows Fig.12 .

[0098] Comparative Example 4

[0099] This comparative example provides a Ni-based deformed high-temperature alloy HT700T alloy electrolytic polishing liquid and its application. Compared with Example 1, this comparative example is different only in that 37% nitric acid is used in the electrolytic polishing liquid instead of hydrochloric acid in the electrolytic polishing liquid. Fig.13 This is the inverse pole figure collected by EBSD technology after the sample was electrolytically polished. The black area is unresolved, and it can be seen that the electrolytic polishing effect is very poor.

[0100] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A metal material electrolytic polishing liquid, It is characterized in that It includes acid substances including sulfuric acid and hydrochloric acid, alcohol substances including methanol and ethanol, and water. Calculated by volume percentage, the volume percentage of the acid substances is 15-30%, the volume percentage of the alcohol substances is 60-80%, and the balance is water.

2. The metal material electrolytic polishing liquid according to claim 1, It is characterized in that The acid substance is a mixture of any two of phosphoric acid, oxalic acid and acetic acid with sulfuric acid and hydrochloric acid.

3. The metal material electrolytic polishing liquid according to claim 2, It is characterized in that The acid substance is a mixture of sulfuric acid, hydrochloric acid, phosphoric acid and oxalic acid in a volume ratio of 4-6:1-3:1-2:1-2, or a mixture of sulfuric acid, hydrochloric acid, phosphoric acid and acetic acid in a volume ratio of 4-6:1-3:1-2:1-2, or a mixture of sulfuric acid, hydrochloric acid, oxalic acid and acetic acid in a volume ratio of 4-6:1-3:1-2:1-2; the mass concentration of sulfuric acid is 98.3%, the mass concentration of hydrochloric acid is 36-38%, the mass concentration of phosphoric acid is 95%, the mass concentration of oxalic acid is greater than 99.5%, and the mass concentration of acetic acid is 99.8%.

4. The metal material electrolytic polishing liquid according to claim 1, It is characterized in that The alcohol substance is a mixture of any two of ethylene glycol, propylene glycol and n-butanol with methanol and ethanol.

5. The metal material electrolytic polishing liquid according to claim 4, It is characterized in that The alcohol substance is a mixture of methanol, ethanol, ethylene glycol and propylene glycol in a volume ratio of 6-8:2-3:1-2:1-2, or a mixture of methanol, ethanol, ethylene glycol and n-butanol, or a mixture of methanol, ethanol, propylene glycol and n-butanol.

6. A method for preparing a metal material electrolytic polishing liquid as claimed in any one of claims 1 to 5, It is characterized in that The following steps are involved: After the acid substances containing sulfuric acid and hydrochloric acid are mixed with water, the alcohol substances containing methanol and ethanol are added and stirred evenly to obtain the metal material electrolytic polishing liquid.

7. A method for preparing EBSD samples, It is characterized in that The following steps are involved: The polished metal material sample preparation surface is used as the anode and the stainless steel plate is used as the cathode, and the electrolytic polishing liquid described in any one of claims 1 to 5 is used for electrolytic polishing.

8. The EBSD sample preparation method according to claim 7, It is characterized in that The sample preparation surface of metal materials shall be W2.5 grain size or above; The parameters of electrolytic polishing are: voltage 20-50V, current density 1-5A / cm 2 , time 10-30s.

9. The EBSD sample preparation method according to claim 7, It is characterized in that The front side of the metal material sample preparation surface is parallel to and directly opposite the stainless steel plate, and the front side of the metal material sample preparation surface is 4-8 cm away from the stainless steel plate.

10. The EBSD sample preparation method according to claim 7, It is characterized in that The area ratio of the stainless steel plate to the metal material sample preparation surface is (4-10):1; The metal material is nickel-based high-temperature alloy, iron-based high-temperature alloy, cobalt-based high-temperature alloy, austenitic heat-resistant steel, titanium, copper or copper alloy.

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