阅读说明：本技术 一种可实现单相固溶体高熵合金的电化学抛光方法 (Electrochemical polishing method capable of realizing single-phase solid solution high-entropy alloy ) 是由 董多 李旭敏 王晓红 朱冬冬 马腾飞 张元祥 周兆忠 于 2021-11-08 设计创作，主要内容包括：本发明公开了一种可实现单相固溶体高熵合金的电化学抛光方法,具体是将耐蚀元素(Mo元素)的高熵合金在常温下进行电化学抛光,以FeCoCrNiMo合金为研究对象,在常压下Mo的不同含量和相同含量下的4GPa和7GPa的合金材料,与常温下电化学抛光后的合金材料进行扫描电镜(SEM)下的微观组织和元素分布图进行比对,研究单相固溶体高熵合金电化学抛光的结果。本发明在常温条件下研究单相固溶体高熵合金的电化学抛光方法,对于探索并建立单相固溶体的电化学抛光过程中一些基本理论,扩展单相固溶体电化学抛光耐腐蚀新材料的可能性具有极大的意义。(The invention discloses an electrochemical polishing method capable of realizing single-phase solid solution high-entropy alloy, which specifically comprises the steps of carrying out electrochemical polishing on high-entropy alloy of corrosion-resistant elements (Mo elements) at normal temperature, taking FeCoCrNiMo alloy as a research object, comparing alloy materials of 4GPa and 7GPa with different contents and the same content of Mo under normal pressure with a microstructure and an element distribution diagram of the alloy material after the electrochemical polishing at normal temperature under a Scanning Electron Microscope (SEM), and researching the electrochemical polishing result of the single-phase solid solution high-entropy alloy. The electrochemical polishing method for the single-phase solid solution high-entropy alloy is researched under the normal temperature condition, and has great significance for exploring and establishing some basic theories in the electrochemical polishing process of the single-phase solid solution and expanding the possibility of the electrochemical polishing corrosion-resistant new material of the single-phase solid solution.)

1. An electrochemical polishing method capable of realizing single-phase solid solution high-entropy alloy is characterized by comprising the following steps:

FeCoCrNiMo_XImmersing the high-entropy alloy in a polishing agent prepared from perchloric acid and alcohol, wherein x is in the range of 0,1](ii) a The high entropy alloy is then electrochemically polished to erode its surface.

2. The electrochemical polishing method for realizing single-phase solid solution high-entropy alloy according to claim 1, wherein the FeCoCrNiMo_XThe high-entropy alloy is prepared by melting and solidifying Mo blocks, Co blocks, Cr blocks, Fe blocks and Ni blocks under normal pressure, and the corresponding electrochemical polishing parameters are voltage of 20V, current of 0.5-0.6A and time of 20 s.

3. The electrochemical polishing method for realizing single-phase solid solution high-entropy alloy according to claim 1, wherein the FeCoCrNiMo_XThe high-entropy alloy is prepared by melting and solidifying Mo blocks, Co blocks, Cr blocks, Fe blocks and Ni blocks at normal pressure and then reacting at high temperature and high pressure, and the corresponding electrochemical polishing parameters are voltage 23V, current 0.4-0.6A and time 10 s.

4. An electrochemical polishing method capable of realizing a single-phase solid solution high entropy alloy, according to claim 2 or 3, characterized in that the purity of the Mo, Co, Cr, Fe and Ni blocks is 99.99%.

5. An electrochemical polishing method capable of realizing single-phase solid solution high entropy alloy according to claim 2 or 3, characterized in that the melting solidification process is realized in an electric arc furnace.

6. An electrochemical polishing method capable of realizing the high-entropy alloy with single-phase solid solution according to claim 3, wherein the temperature is 1600 ℃ -1800 ℃ and the pressure is 4 GPa-7 GPa during the high-temperature high-pressure reaction process.

7. The electrochemical polishing method for realizing single-phase solid solution high-entropy alloy according to claim 1, wherein the FeCoCrNiMo_XThe high-entropy alloy is a round bar structure with phi 3 multiplied by 3.7 mm.

8. The electrochemical polishing method for realizing single-phase solid solution high-entropy alloy according to claim 1, wherein the FeCoCrNiMo_XThe atomic ratio x of the Mo content in the high-entropy alloy is 0, 0.1 or 0.3.

9. The electrochemical polishing method for realizing single-phase solid solution high entropy alloy, according to claim 1, wherein the volume ratio of perchloric acid to alcohol in the polishing agent is 1: 9-1: 15.

10. the electrochemical polishing method for realizing single-phase solid solution high-entropy alloy according to claim 1, wherein the FeCoCrNiMo is added_XThe high-entropy alloy is connected with the anode of an electrolytic polishing machine through a lead, and meanwhile, a conductive object in contact with a polishing agent is connected with the cathode of the electrolytic polishing machine through a lead to carry out electrochemical polishing; after the reaction is finished, cleaning the corroded FeCoCrNiMo by alcohol_XHigh entropy alloy surface.

Technical Field

The invention belongs to the technical field of electrochemistry, and particularly relates to an electrochemical polishing method capable of realizing single-phase solid solution high-entropy alloy.

Background

Solid solution refers to an alloy phase in which solute atoms dissolve into the solvent lattice while still maintaining the solvent type. Solid solutions with only one phase are called single phase solid solutions. The solid solution generally has good mechanical property, and the crystal lattice structure has certain distortion and is in a high-energy activation state, thereby being beneficial to carrying out chemical reaction. The high-entropy alloy has excellent mechanical properties, high thermal stability, high hardness, wear resistance and other excellent properties, so that the high-entropy alloy is expected to become a plurality of engineering applications as a structural material. But the corrosion resistance of the alloy is reduced by electrochemical polishing, and the corrosion resistance of other alloys can be used for reference. The material has great significance for high-performance warhead materials, materials for polar icebreaking ships and the like. The material is combined with the calculation of the first principle and the phase diagram simulation design and the alloy components are optimized, and the corrosion resistance of other alloys is improved by adopting the advanced material preparation technology and the electrochemical treatment method after the alloy through electrochemical polishing. Therefore, it is necessary to search for an electrochemical polishing method capable of realizing a single-phase solid solution high-entropy alloy.

The material waste caused by corrosion in China every year is very serious, and the research and development of materials with better corrosion resistance have important significance for saving resources. As the research on the corrosion performance of the high-entropy alloy is relatively late in China, along with the deep research, the research on the regulation and control of the microstructure and the improvement of the corrosion resistance of the alloy and the research on the high-entropy alloy passivation film are gradually developed, but the research is also in a preliminary stage and still lacks systematicness and guidance. According to the current research situation of the high-entropy alloy, comprehensive and systematic research on the corrosion behavior and mechanism of the high-entropy alloy is urgently needed. The invention corrodes the high-entropy alloy through electrochemical polishing, so that the obtained alloy has consistent internal and external colors, and has certain effect on corrosion of the high-entropy alloy. In addition, the machine is low in investment cost and high in efficiency. According to the invention, through observation of the surface morphology of the alloy, the corrosion resistance of the alloy is reduced by electrochemical polishing, so that the alloy performance is more effectively improved by microstructure regulation. For the high-entropy alloy, besides the mechanical property, the service life of the material and the safety problem in the service process are greatly dependent on the corrosion property of the material, and the safety evaluation of the service condition of the high-entropy alloy and the research on the corrosion property of the high-entropy alloy are very necessary. Therefore, the electrochemical polishing method capable of realizing the single-phase solid solution high-entropy alloy is of great significance in research.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides an electrochemical polishing method capable of realizing single-phase solid solution high-entropy alloy.

The invention adopts the following specific technical scheme:

the invention provides an electrochemical polishing method capable of realizing single-phase solid solution high-entropy alloy, which comprises the following steps:

FeCoCrNiMo_XImmersing the high-entropy alloy in a polishing agent prepared from perchloric acid and alcohol, wherein x is in the range of 0,1](ii) a The high entropy alloy is then electrochemically polished to erode its surface.

Preferably, the FeCoCrNiMo_XThe high-entropy alloy is prepared by melting and solidifying Mo blocks, Co blocks, Cr blocks, Fe blocks and Ni blocks under normal pressure, and the corresponding electrochemical polishing parameters are voltage of 20V, current of 0.5-0.6A and time of 20 s.

Furthermore, the purities of the Mo blocks, the Co blocks, the Cr blocks, the Fe blocks and the Ni blocks are all 99.99%.

Further, the melting and solidifying process is realized in an electric arc furnace.

Further, in the high-temperature high-pressure reaction process, the temperature is 1600-1800 ℃ and the pressure is 4-7 GPa.

Preferably, the FeCoCrNiMo_XThe high-entropy alloy is prepared by melting and solidifying Mo blocks, Co blocks, Cr blocks, Fe blocks and Ni blocks at normal pressure and then reacting at high temperature and high pressure, and the corresponding electrochemical polishing parameter is voltage 23V, current of 0.4-0.6A and time of 10 s.

Furthermore, the purities of the Mo blocks, the Co blocks, the Cr blocks, the Fe blocks and the Ni blocks are all 99.99%.

Further, the melting and solidifying process is realized in an electric arc furnace.

Preferably, the FeCoCrNiMo_XThe high-entropy alloy is a round bar structure with phi 3 multiplied by 3.7 mm.

Preferably, the FeCoCrNiMo_XThe atomic ratio x of the Mo content in the high-entropy alloy is 0, 0.1 or 0.3.

Preferably, in the polishing agent, the mixing volume ratio of perchloric acid to alcohol is 1: 9-1: 15.

preferably, the FeCoCrNiMo_XThe high-entropy alloy is connected with the anode of an electrolytic polishing machine through a lead, and meanwhile, a conductive object in contact with a polishing agent is connected with the cathode of the electrolytic polishing machine through a lead to carry out electrochemical polishing; after the reaction is finished, cleaning the corroded FeCoCrNiMo by alcohol_XHigh entropy alloy surface.

Compared with the prior art, the invention has the following beneficial effects:

1) the electrochemical polishing method provided by the invention has great significance for establishing a new corrosion theory for the single-phase solid solution;

2) because the corrosion resistance of the alloy is reduced by electrochemical polishing, the alloy performance can be more effectively improved by microstructure regulation, and therefore, the electrochemical polishing method has great application potential in the aspect of regulating and improving the corrosion resistance of the alloy by the microstructure of the single-phase solid solution.

Drawings

FIG. 1 is a schematic illustration of an assembled sample during electrochemical polishing;

fig. 2 is a structural morphology of the FeCoCrNiMo alloy in example 1 under different Mo contents (Mo is 0, 0.1, 0.3), wherein, the structural morphology of the FeCoCrNiMo alloy with Mo content is 0 (a) and its enlarged image (b), the structural morphology of the FeCoCrNiMo alloy with Mo content is 0.1 (c) and its enlarged image (d), and the structural morphology of the FeCoCrNiMo alloy with Mo content is 0.3 (e) and its enlarged image (f);

FIG. 3 is FeCoCrNiMo in example 1_0.3The alloy has the structure appearance under different pressures (0GPa, 4GPa and 7GPa), wherein FeCoCrNiMo_0.3The structural morphology of the alloy under 0GPa is shown in (a) and an enlarged image (b), FeCoCrNiMo_0.3The structural morphology of the alloy under 4GPa is shown in (c) and an enlarged image (d), FeCoCrNiMo_0.3The microstructure and the morphology of the alloy under 7GPa are shown in a graph (e) and a magnified image (f);

fig. 4 is a structural morphology of FeCoCrNiMo alloy of example 2 after electrochemical polishing with different Mo contents (Mo is 0, 0.1, 0.3), wherein the structural morphology (a) and the enlarged image (b) of FeCoCrNiMo alloy with Mo content of 0 after electrochemical polishing, the structural morphology (c) and the enlarged image (d) of FeCoCrNiMo alloy with Mo content of 0.1 after electrochemical polishing, and the structural morphology (e) and the enlarged image (f) of FeCoCrNiMo alloy with Mo content of 0.3 after electrochemical polishing;

FIG. 5 is FeCoCrNiMo after electrochemical polishing in example 2_0.3The alloy has the structure appearance under different pressures (0GPa, 4GPa and 7GPa), wherein FeCoCrNiMo is subjected to electrochemical polishing_0.3The microstructure and the appearance of the alloy under 0GPa are shown in (a) and an enlarged image (b), and FeCoCrNiMo is electrochemically polished_0.3The structural morphology of the alloy under 4GPa is shown in (c) and an enlarged image (d), and FeCoCrNiMo is shown after electrochemical polishing_0.3The microstructure and topography (e) and the magnified image (f) of the alloy at 7 GPa;

FIG. 6 shows the different contents of FeCoCrNiMo alloy (fig. a) b) c) d) e) M) after electrochemical polishing in example 2₀F) g) h) i) j) k) M_0.1FIG. l) M) n) o) p) q) M_0.3) Scanning the lower surface;

FIG. 7 is FeCoCrNiMo after electrochemical polishing in example 2_0.3The alloys were surface scanned at different pressures (fig. a) b) c) d) e) f)0GPa, g) h) i) j) l)4GPa, m) n) o) p) r)7 GPa).

Detailed Description

The invention will be further elucidated and described with reference to the drawings and the detailed description. The technical features of the embodiments of the present invention can be combined correspondingly without mutual conflict.

Example 1

1) Weighing Mo blocks, Co blocks, Cr blocks, Fe blocks and Ni blocks with the purity of 99.99%, cleaning, melting and solidifying in an electric arc furnace, and respectively preparing FeCoCrNiMo with different Mo contents_XThe alloys (x ═ 0, 0.1, 0.3) were finally cut into round bars of Φ 3 × 3.7mm, and the samples Mo0, mo0.1, and mo0.3 were recorded.

2) Grinding the round bar obtained in the step 1) by using 1500-mesh abrasive paper to remove cutting marks, cleaning, and then putting all test materials such as pyrophyllite and the like into a forced air drying oven to be dried for later use.

3) Taking two samples Mo0.3 dried in the step 2), and respectively pressurizing to 4GPa and 7GPa in a high-temperature high-pressure press at 1700 ℃ to obtain samples 4GPaMo0.3 and 7 GPaMo0.3.

4) According to volume ratio, perchloric acid: alcohol 1: 15, preparing a polishing agent.

5) Samples Mo0, Mo0.1, Mo0.3, 4GPaMo0.3 and 7GPaMo0.3 are respectively taken and immersed in the polishing agent, the samples are connected with the anode of an electrolytic polishing machine through leads, meanwhile, a conductive object in contact with the polishing agent is connected with the cathode of the electrolytic polishing machine through leads, the samples are assembled as shown in figure 1 and then subjected to electrolytic polishing, parameters such as voltage, time, current and the like are adjusted for corrosion, the samples are cleaned by alcohol and then dried, and the surface characterization of the corroded samples is observed.

Wherein, for samples (Mo0, Mo0.1 and Mo0.3) prepared under normal pressure, the selected electrochemical polishing parameters are voltage of 20V, current of 0.5-0.6A and time of 20 s; for samples prepared at high pressure (4GPaMo0.3 and 7GPaMo0.3), the electrochemical polishing parameters selected were voltage 23V, current 0.4-0.6A, and time 10 s.

6) Observing the corroded sample by using an optical microscope, returning to the step 5) for operation and debugging again if the phenomena of obvious scratch and the like do not exist, and till a clear phase appears.

7) After the experiment is finished, the power supply of the electrolytic polishing machine is turned off, the solution is poured out, and the beaker is cleaned.

In order to better observe the influence of electrochemical polishing on the single-phase solid-solution high-entropy alloy, a simple analysis can be carried out on the sample before the electrochemical polishing, and the method comprises the following specific steps:

1) starting up a scanning electron microscope;

2) setting a sample table according to the height, placing, checking and fixing;

3) attaching the polished samples (Mo0, Mo0.1, Mo0.3, 4GPaMo0.3 and 7GPaMo0.3) to a sample table by using a conductive adhesive tape, putting the samples into the sample table, and vacuumizing the sample table;

4) opening the sample image, and adjusting the image to be clear;

5) photographing according to the required multiple;

6) and selecting a saving path and saving the shot image.

The results are shown in FIGS. 2 and 3, in which FIGS. 2 and 3 are FeCoCrNiMo_XThe surface structure appearance of the alloy under different contents and the same content and different pressures under normal pressure. As can be seen in the figure, FeCoCrNiMo before no electrochemical polishing_XThe alloy is a single phase, and the alloy with the Mo content of 0 has obvious columnar crystal grains under normal pressure, and the alloy with the Mo content of 0.1 and 0.3 also has the appearance of the columnar crystal grains, but is not obvious as compared with the alloy with the Mo content of 0. FeCoCrNiMo after pressurization_0.3A part of white small particles are precipitated from the alloy.

The polished samples (Mo0, Mo0.1, Mo0.3, 4GPaMo0.3 and 7GPaMo0.3) are analyzed to obtain the surface morphology structure and element distribution of the material by scanning, and the details are as follows:

(1) the scanning electron microscope was turned on.

(2) The sample stage is specified according to the height, placed, checked and fixed.

(3) And (3) attaching the sample to a sample table by using a conductive adhesive tape, putting the sample in the sample table, and vacuumizing the sample table.

(4) And opening the sample image, and adjusting the image to be clear.

(5) And taking pictures according to the required times.

(6) And selecting a saving path and saving the shot image.

(7) Turn on the energy spectrum analysis and receive electron microscope images.

(8) And observing the image, and selecting a point scan and a surface scan at the position to be analyzed.

(9) The energy spectrum of the sample is preserved.

The results are shown in fig. 4 and fig. 5, and fig. 4 and fig. 5 show the surface structure morphology of the FeCoCrNiMo high-entropy alloy under different contents and the same content under different pressures at normal pressure, respectively. As can be seen from the figure, the microstructure of the high-entropy alloy FeCoCrNiMo is changed greatly under normal pressure or pressurization after electrochemical polishing. The phase after electrochemical polishing is uneven and uniformly distributed, the convex part is gradually changed from a round shape into a cross shape along with the increase of the content of Mo under normal pressure, and small particles are gradually separated out on the surface of the phase. FeCoCrNiMo_0.3The phases "round" and "cross" of the convex part alternate at high pressure, but still "cross" predominates. The depressed portions have small white particles agglomerated together.

In order to better study the influence of electrochemical polishing of Mo with different contents and the same contents and different pressures (4GPa and 7GPa) on the alloy under normal pressure, the structure shape after electrochemical polishing is subjected to surface scanning. As a result, as shown in fig. 6 and 7, it can be seen that after the electrochemical polishing, the distribution of the elements in the convex portion was less than that in the concave portion, and the distribution of the Mo element was more pronounced in the concave portion than that of the other elements.

The electrochemical polishing method for the single-phase solid solution high-entropy alloy is researched under the normal temperature condition, and has great significance for exploring and establishing some basic theories in the electrochemical polishing process of the single-phase solid solution and expanding the possibility of the electrochemical polishing corrosion-resistant new material of the single-phase solid solution.

The above-described embodiments are merely preferred embodiments of the present invention, which should not be construed as limiting the invention. Various changes and modifications may be made by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present invention. Therefore, the technical scheme obtained by adopting the mode of equivalent replacement or equivalent transformation is within the protection scope of the invention.