CN117604603A - Method for improving corrosion resistance of nickel-based alloy - Google Patents
Method for improving corrosion resistance of nickel-based alloy Download PDFInfo
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- CN117604603A CN117604603A CN202311569698.4A CN202311569698A CN117604603A CN 117604603 A CN117604603 A CN 117604603A CN 202311569698 A CN202311569698 A CN 202311569698A CN 117604603 A CN117604603 A CN 117604603A
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- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 title claims abstract description 120
- 239000000956 alloy Substances 0.000 title claims abstract description 75
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 75
- 229910052759 nickel Inorganic materials 0.000 title claims abstract description 59
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000005260 corrosion Methods 0.000 title claims abstract description 33
- 230000007797 corrosion Effects 0.000 title claims abstract description 31
- 238000005498 polishing Methods 0.000 claims abstract description 78
- 239000003792 electrolyte Substances 0.000 claims abstract description 37
- 244000137852 Petrea volubilis Species 0.000 claims abstract description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000008367 deionised water Substances 0.000 claims abstract description 7
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 7
- 238000006056 electrooxidation reaction Methods 0.000 claims description 6
- 230000010287 polarization Effects 0.000 description 29
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 28
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 25
- 239000000243 solution Substances 0.000 description 23
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 14
- 239000011780 sodium chloride Substances 0.000 description 14
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 11
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 10
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 7
- 238000002161 passivation Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 238000007517 polishing process Methods 0.000 description 6
- 229960000583 acetic acid Drugs 0.000 description 5
- 238000004140 cleaning Methods 0.000 description 5
- 239000002360 explosive Substances 0.000 description 5
- 239000012362 glacial acetic acid Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000006467 substitution reaction Methods 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- 238000000840 electrochemical analysis Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 229910003460 diamond Inorganic materials 0.000 description 2
- 239000010432 diamond Substances 0.000 description 2
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical group Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- XTEGARKTQYYJKE-UHFFFAOYSA-N chloric acid Chemical compound OCl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-N 0.000 description 1
- 229940005991 chloric acid Drugs 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003487 electrochemical reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000011553 magnetic fluid Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-M perchlorate Inorganic materials [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- -1 salt compound Chemical class 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F3/00—Electrolytic etching or polishing
- C25F3/16—Polishing
- C25F3/22—Polishing of heavy metals
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
- C25F7/00—Constructional parts, or assemblies thereof, of cells for electrolytic removal of material from objects; Servicing or operating
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Sampling And Sample Adjustment (AREA)
Abstract
The invention discloses a method for improving corrosion resistance of nickel-base alloys, and belongs to the technical field of corrosion resistance of nickel-base alloys. The method comprises the steps of at room temperature, polishing a nickel-based alloy sample by sand paper, directly placing the nickel-based alloy sample as an anode in the middle of a magnetic pole, wherein the magnetic field direction is parallel to the surface of the sample, the magnetic field strength is 0.1-0.5T, a nickel sheet is used as a cathode, and placing the anode and the cathode in an electrolytic tank filled with electrolyte for electrolytic polishing; the power supply voltage is 30-60V, and the time is controlled to be 60-120 s; the electrolyte is H 3 PO 4 And H is 2 SO 4 Electrolyte with the volume ratio of 7:1-9:1; after the end of the magnetic electrolytic polishing, the electrolyte remained on the surface of the sample is washed by deionized water. The method of the invention not only obviously improves the corrosion resistance of the nickel-based alloy, but also omits the mechanical polishing step, saves labor, obviously improves the efficiency, is simple and easy to operate, has low cost and is suitable for popularization and use.
Description
Technical Field
The invention belongs to the technical field of corrosion resistance of nickel-based alloys, and particularly relates to a method for improving corrosion resistance of a nickel-based alloy.
Background
Nickel-based alloys are commonly used in relatively corrosive environments, and the corrosion resistance of these alloys is critical to long-term economic and safe service. Nickel-based 52M alloys having relatively high chromium content have been used as weld metals for weldments or weld overlays in some equipment components. Because the corrosion behavior of the metal material is determined by the material itself and the environmental medium, factors such as the surface morphology, surface composition, microstructure, residual stress and the like of the material also influence the corrosion resistance of the material to a great extent.
According to the research results of improving the corrosion resistance of stainless steel materials by utilizing the electrolytic polishing technology, it can be understood that the electrolytic polishing can not only smooth the surface by dissolving tiny convex parts on the metal surface, but also reduce the stress in the workpiece and on the surface, and the polished metal surface is smoother and more durable than the mechanical polishing. However, there is still room for further improvement due to the surface after electropolishing, and heat is generated during electropolishing, which affects the operation process and the polishing effect.
The nickel-based alloy (mainly contains nickel and also generally contains higher Cr) has different corrosion resistance due to a great component difference with stainless steel (mainly contains iron), so that the electrolytic polishing technology applied to the stainless steel at present is not easy to be directly and commonly used in the nickel-based alloy. The operation method is not simple enough in steps and high in cost.
Disclosure of Invention
The invention aims to provide a method for improving the corrosion resistance of a nickel-based alloy, which can obtain a smoother surface without carrying out mechanical polishing treatment on the surface of a material by directly introducing an external specific magnetic field, further improves the corrosion resistance of the nickel-based alloy, greatly reduces the workload, saves labor and obviously improves the efficiency because the mechanical polishing step is omitted.
Specifically, the invention designs a method for adopting an external magnetic field: the electrolyte adopts the environment-friendly and cheap mixed solution of phosphoric acid and sulfuric acid, does not use perchloric acid which is expensive and has explosion hidden danger, and is economical and safe; meanwhile, the electrolytic polishing can be carried out at room temperature, and the operation is simple and easy.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
a method for improving corrosion resistance of a nickel-based alloy, the method comprising the process steps of:
at room temperature, polishing a nickel-based alloy sample by sand paper, directly placing the nickel-based alloy sample as an anode in the middle of a magnetic pole, wherein the magnetic field direction is parallel to the surface of the sample, the magnetic field strength is 0.1-0.5T, a nickel sheet is used as a cathode, and placing the anode and the cathode in an electrolytic tank filled with electrolyte for electrolytic polishing; the power supply voltage is 30-60V, and the time is controlled to be 60-120 s; the electrolyte is H 3 PO 4 And H is 2 SO 4 Electrolyte with the volume ratio of 7:1-9:1; after the end of the magnetic electrolytic polishing, the electrolyte remained on the surface of the sample is washed by deionized water.
Preferably, in said step, the magnetic field strength is 0.3T.
Preferably, in the step, the power supply voltage is 40V and the time is controlled to be 60s.
Preferably, the electrolyte is H 3 PO 4 And H is 2 SO 4 Electrolyte with the volume ratio of 9:1. Preferably, the nickel-based alloy in the above steps is nickel-based 52M alloy.
Preferably, said H 3 PO 4 The mass fraction is more than or equal to 85 percent.
Preferably, said H 2 SO 4 The mass fraction is 95-98%.
Preferably, the electrolyte is not agitated during the electrolytic polishing.
After the electrolytic polishing is finished, the corrosion resistance of the nickel-based alloy is evaluated by adopting an electrochemical test method:
(1) the nickel-based alloy sheet sample subjected to the electrolytic polishing treatment is used as a working electrode, forms a three-electrode system with a reference electrode and an auxiliary electrode, and is communicated with an electrochemical workstation;
(2) immersing a working electrode of the electrode system in a corrosive solution, and waiting for self-corrosion potential to reach a stable state; performing electrokinetic potential scanning, wherein the electrokinetic potential scanning starts from an open circuit potential to an over passivation region potential;
(3) according to the potentiodynamic scanning curve, selecting to carry out potentiostatic polarization under a certain potential;
(4) and observing the corrosion morphology of the surface of the working electrode after constant potential polarization.
In the test step, all electrochemical test processes are repeated for not less than 3 times.
In the step (1), the working electrode is nickel-based alloy with the exposed diameter not smaller than 5mm, the reference electrode is saturated calomel electrode, and the auxiliary electrode is a platinum sheet electrode. (2) Wherein the working electrode is soaked in corrosive solution for 30-60 min, the solution is NaCl with the concentration of 0.1-2 mol/L, the scanning potential is 0V (relative to open circuit potential OCP) to 1.5V (relative to reference electrode SCE), and the scanning speed is 50-100 mv/min. (3) According to the electrokinetic potential scanning curve, constant potential polarization is carried out under a certain potential, the polarization potential is a certain potential between 0.1 and 0.8V, and the polarization time is 200 to 600s.
The invention is used for comparison, and meanwhile, the surface of the nickel-based alloy sheet sample is subjected to the following mechanical polishing and electrolytic polishing:
polishing the nickel-based alloy polished by sand paper by using a diamond scrub of 1 mu m to obtain a mechanical polishing sample; the negative electrode of the direct current power supply is connected with a nickel-based alloy sample polished by sand paper, the positive electrode is connected with a large-area nickel sheet, and the nickel-based alloy sample and the positive electrode are put into an electrolytic tank filled with the electrolyte together for electrolytic polishing, wherein the power supply voltage is 30-60V, and the time is controlled to be 60-120 s.
Electrochemical tests are carried out on the alloy subjected to mechanical polishing, electrolytic polishing and magnetic electrolytic polishing, and the effectiveness of the magnetic electrolytic polishing method for improving the corrosion resistance of the nickel-based alloy is qualitatively analyzed, and the following method is adopted:
comparing anodic polarization curves of the alloy subjected to mechanical polishing, electrolytic polishing and magnetic electrolytic polishing in 2mol/L NaCl solution, current response under constant potential of 0.4-0.8V polarization and surface morphology after 0.8V potential polarization; the over-passivation potential of the magnetic polishing sample was found to be highest, the current density was minimum, and the surface after polarization had no obvious trace of corrosion. The magnetic electrolytic polishing process not only improves the roughness of the surface of the nickel-based alloy sample, but also accelerates the selective dissolution of alloy elements on the surface of the sample, so that a passivation film with better protection is formed on the surface of the sample.
Compared with the traditional technical scheme of perchloric acid and glacial acetic acid electrolyte, the technical scheme of phosphoric acid and sulfuric acid electrolyte has the following outstanding substantial characteristics:
1. the mechanical polishing process step is omitted, and the nickel-based alloy sample is directly used as an anode to carry out magnetic electrolytic polishing after being polished by sand paper; the technical scheme of the traditional perchloric acid and glacial acetic acid electrolyte is that the sample is polished by sand paper and then is mechanically polished, and then is magnetically polished, and the effect that the mechanical polishing process step is not adopted can be achieved, so that the workload is greatly reduced, the manpower is saved, and the efficiency is obviously improved.
2. The cost of the phosphoric acid and sulfuric acid electrolyte is saved by 61.4 percent compared with that of the chloric acid and glacial acetic acid electrolyte; perchloric acid is expensive, and the market price (products and products) perchloric acid in 2023 is about 690 yuan/500 ml (AR. Grade); glacial acetic acid is about 19.32 yuan/500 ml (ar. Grade), phosphoric acid is about 64.4 yuan/500 ml (ar. Grade), and sulfuric acid is about 18.4 yuan/500 ml (ar. Grade).
3. The invention has high safety and can not explode. Pure perchloric acid is colorless liquid, is unstable, can explode in storage at times, and can react with organic matters violently when heated and at high concentration, so that the perchloric acid needs to be stored in a special place at low temperature; the explosive is the property that chemicals can be used as raw materials or auxiliary materials to prepare explosives, and according to the name of explosive dangerous chemicals (2021 edition), the explosive dangerous chemicals can be classified into six types including perchloric acid/perchlorate, so that the explosive dangerous chemicals have potential safety hazards in practical use.
4. The measuring process is easy to control, and is carried out at room temperature; and when perchloric acid is used as electrolyte for electrolytic polishing, the temperature needs to be controlled to be 6 ℃ or lower, and the electrolytic polishing is not easy to realize in actual field operation.
5. Compared with the traditional technical scheme of perchloric acid and glacial acetic acid electrolyte, the technical scheme of the invention adopts phosphoric acid and sulfuric acid electrolyte, and an electrochemical reaction mechanismDifferent: (1) The boundary layer in the electrolysis of perchloric acid is perchloric acid and metal ions (Ni 2+ ) A complex layer formed; (2) The boundary layer in the electrolysis of phosphoric acid (mainly phosphoric acid) -sulfuric acid is the phosphate and metal ions (Ni 2 + ) The salt compound layers are all in liquid form and are not separated out into solid layers, and the magnetic fluid dynamic flow of the boundary layer is disturbed due to the external magnetic field.
In addition, compared with the prior electrolytic polishing technology, the invention is carried out after the sand paper is polished, so that the invention is more suitable for engineering application; the invention has good measurement repeatability; the method is simple and feasible, saves operation steps, reduces cost and is suitable for popularization and use.
Drawings
FIG. 1 shows the anodic polarization curves of examples 1-3 according to the invention in a 2mol/L NaCl solution.
FIG. 2 is a graph showing the current density response of examples 1-3 of the present invention under 0.4V potentiostatic polarization in a 2mol/L NaCl solution.
FIG. 3 is a graph showing the current density response of examples 1-3 of the present invention under 0.6V potentiostatic polarization in a 2mol/L NaCl solution.
FIG. 4 is a graph showing the current density response of examples 1-3 of the present invention under 0.8V potentiostatic polarization in a 2mol/L NaCl solution.
FIG. 5 is a graph showing the surface morphology of example 1 of the present invention after 0.8V potentiostatic polarization in 2mol/L NaCl solution.
FIG. 6 is a graph showing the surface morphology of example 2 of the present invention after 0.8V potentiostatic polarization in 2mol/L NaCl solution.
FIG. 7 is a chart showing the surface morphology of example 3 of the present invention after 0.8V potentiostatic polarization in 2mol/L NaCl solution.
FIG. 8 is an anodic polarization curve of an alloy after mechanical polishing, electropolishing and magnetic polishing in a 0.6mol/LNaCl solution.
Detailed Description
The following description of the present invention will further explain the technical solution of the present invention by means of the specific embodiments with reference to the accompanying drawings, but is not limited thereto, and all technical solutions obtained by modifying the technical solution of the present invention or adopting equivalent substitution or equivalent variation fall within the protection scope of the present invention.
The foregoing aspects are further described in conjunction with specific embodiments, and the following detailed description of preferred embodiments of the present invention is provided:
example 1
In this example, the method of the present invention comprises the steps of:
mechanically polishing the alloy surface:
sequentially polishing the surface of the nickel-based 52M alloy by using No. 600, no. 1000 and No. 1500 water abrasive paper to obtain a smooth surface, mechanically polishing by using a 1 mu M diamond polishing paste, and sequentially cleaning the surface of the alloy sample by using absolute ethyl alcohol and deionized water.
Example 2
Electropolishing the alloy surface:
sequentially polishing the surface of the nickel-based 52M alloy by using No. 600, no. 1000 and No. 1500 water-based abrasive paper to obtain a smooth surface, and then sequentially cleaning the surface of the alloy sample by using absolute ethyl alcohol and deionized water; the negative electrode of the direct current power supply is connected with a nickel-based alloy sample polished by sand paper, the positive electrode is connected with a large-area nickel sheet, and the nickel-based alloy sample and the positive electrode are put into an electrolytic tank filled with the electrolyte together for electrolytic polishing, wherein the power supply voltage is 40V, and the time is controlled to be 60s; the electrolyte is H with the volume ratio of 9:1 3 PO 4 (mass fraction is more than or equal to 85%) and H 2 SO 4 The electrolyte is 95-98% by mass.
Example 3
Magneto-electrolytic polishing of alloy surfaces:
sequentially polishing the surface of the nickel-based 52M alloy by using No. 600, no. 1000 and No. 1500 water-based abrasive paper to obtain a smooth surface, and then sequentially cleaning the surface of the alloy sample by using absolute ethyl alcohol and deionized water; the negative electrode of the direct current power supply is connected with a nickel-based alloy sand paper polishing sample, the positive electrode is connected with a large-area nickel sheet, the nickel-based alloy sand paper polishing sample and the positive electrode are put into an electrolytic tank filled with the electrolyte, a magnetic field is added, the nickel-based alloy is placed in the middle of a magnetic pole as an anode, the magnetic field direction is parallel to the surface of the sample, the magnetic field strength is 0.3T, the nickel sheet is used as a cathode, the magnetic electrolytic polishing is carried out, the power supply voltage is 40V, the time is controlled at 60s, and the electrolyte is not stirred. After the end of the magnetic electrolytic polishing processAnd (3) cleaning the electrolyte remained on the surface of the sample by using deionized water. The electrolyte is H with the volume ratio of 9:1 3 PO 4 (mass fraction is more than or equal to 85%) and H 2 SO 4 (the mass fraction is 95% -98%) of the mixed electrolyte.
The electrochemical corrosion test was performed on the above examples 1 to 3, and the procedure was as follows:
(1) the nickel-based alloy sheet sample subjected to mechanical polishing, electrolytic polishing and magnetic electrolytic polishing is used as a working electrode, a three-electrode system is formed by the nickel-based alloy sheet sample, a reference electrode and an auxiliary electrode, the three-electrode system is communicated with an electrochemical workstation, the working electrode is nickel-based 52M alloy with the exposed diameter of 5mm, the reference electrode is a saturated calomel electrode, and the auxiliary electrode is a platinum sheet electrode;
(2) immersing a working electrode of the electrode system in a corrosive solution, and waiting for self-corrosion potential to reach a stable state; performing electrokinetic potential scanning, wherein the electrokinetic potential scanning starts from an open circuit potential to an over passivation region potential; the soaking time is 60min, the solution is NaCl with the concentration of 2mol/L, the scanning potential is 0V (relative to the open circuit potential OCP) to 1.5V (relative to the reference electrode SCE), and the scanning speed is 50mv/min;
(3) according to the potentiodynamic scanning curve, constant potential polarization is carried out under the potential of 0.8V, and the polarization time is 300s;
(4) and observing the corrosion morphology of the surface of the working electrode after 0.8V constant potential polarization.
All electrochemical testing processes were repeated no less than 3 times.
Comparing anodic polarization curves of the alloy subjected to mechanical polishing, electrolytic polishing and magnetic-electrolytic polishing in 2mol/L NaCl solution, and qualitatively analyzing the effectiveness of the magnetic-electrolytic polishing method for improving the corrosion resistance of the nickel-based alloy, as shown in FIG. 1;
the sample subjected to the electrolytic polishing after the sanding of the abrasive paper in the anodic polarization curve shown in fig. 1 has the highest over-passivation potential and the smallest current density; therefore, the over-passivation potential of the nickel-based alloy during polarization can be improved by performing the magnetic polishing after the sanding, and the current density is reduced, namely the corrosion resistance of the nickel-based alloy in Cl-solution is improved.
Comparing the current response diagrams of the alloy subjected to mechanical polishing, electrolytic polishing and magnetic electrolytic polishing under constant potential polarization in 2mol/L NaCl solution, and qualitatively analyzing the effectiveness of the magnetic electrolytic polishing method for improving the corrosion resistance of the nickel-based alloy, wherein the effectiveness is shown in figures 2-4;
the current response plots after 0.4V, 0.6V and 0.8V potentiostatic polarization shown in fig. 2-4 show that the current density of the sample subjected to the magneto-electrolytic polishing after sanding is minimal, indicating that the magneto-electrolytic polishing process reduces the dissolution rate of the nickel-based alloy in Cl-solution and improves corrosion resistance.
Comparing the surface morphology of the alloy subjected to mechanical polishing, electrolytic polishing and magnetic electrolytic polishing after 0.8V potential polarization in 2mol/L NaCl solution, and qualitatively analyzing the effectiveness of the magnetic electrolytic polishing method for improving the corrosion resistance of the nickel-base alloy, as shown in figures 5-7;
the 0.8V polarized surface topography of the samples shown in fig. 5-7 shows that many pitting occurred on the surfaces of the mechanically polished samples and electropolished samples, whereas the surfaces of the samples subjected to the magnetic electropolishing after sanding had no noticeable signs of corrosion compared to the other samples.
In summary, the method of the above embodiment includes: polishing the alloy surface by sand paper, mechanically polishing the alloy surface, cleaning a sample, preparing electrolyte, performing electrolytic polishing on the alloy surface, performing electrochemical corrosion test, wherein the electrochemical corrosion test comprises electrokinetic potential scanning in 2mol/L NaCl solution; selecting potential according to the electrokinetic potential curve to carry out constant potential polarization; the surface morphology of the working electrode after constant potential polarization is observed, obvious corrosion marks do not appear after the surface polarization of the nickel-based alloy after the electrolytic polishing is performed by the embodiment, a passivation film which is not easy to be corroded by Cl & lt- & gt and has a protective effect is generated, and the corrosion resistance of the nickel-based alloy can be effectively improved. The invention introduces a magnetic field in the electrolytic polishing process, and compares the mechanical polishing sample, the electrolytic polishing sample and the magnetic polishing sample in high Cl - The electrochemical corrosion behavior in the concentration can be known that the electrochemical corrosion performance of the nickel-based alloy can be improved by the magneto-electrolytic polishing process.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above, and various changes, modifications, substitutions, combinations or simplifications made under the spirit and principles of the technical scheme of the present invention can be made according to the purpose of the present invention, and all the changes, modifications, substitutions, combinations or simplifications should be equivalent to the substitution, so long as the purpose of the present invention is met, and all the changes are within the scope of the present invention without departing from the technical principles and the inventive concept of the present invention.
Claims (8)
1. A method for improving corrosion resistance of a nickel-base alloy, the method comprising the steps of:
at room temperature, polishing a nickel-based alloy sample by sand paper, directly placing the nickel-based alloy sample as an anode in the middle of a magnetic pole, wherein the magnetic field direction is parallel to the surface of the sample, the magnetic field strength is 0.1-0.5T, a nickel sheet is used as a cathode, and placing the anode and the cathode in an electrolytic tank filled with electrolyte for electrolytic polishing; the power supply voltage is 30-60V, and the time is controlled to be 60-120 s; the electrolyte is H 3 PO 4 And H is 2 SO 4 Electrolyte with the volume ratio of 7:1-9:1; after the end of the magnetic electrolytic polishing, the electrolyte remained on the surface of the sample is washed by deionized water.
2. The method of claim 1, wherein the magnetic field strength is 0.3T.
3. The method of claim 1, wherein the power supply voltage is 40V and the time is controlled at 60s.
4. The method for improving electrochemical corrosion performance of a nickel-base alloy according to claim 1, wherein the electrolyte is H 3 PO 4 And H is 2 SO 4 Electrolyte with the volume ratio of 9:1.
5. The method of claim 1, wherein the nickel-based alloy is a nickel-based 52M alloy.
6. According toThe method for improving corrosion resistance of a nickel-base alloy as recited in claim 1, wherein said H 3 PO 4 The mass fraction is more than or equal to 85 percent.
7. The method for improving corrosion resistance of a nickel-base alloy according to claim 1, wherein H 2 SO 4 The mass fraction is 95-98%.
8. The method of claim 1, wherein the electrolyte is not agitated during the magnetic polishing.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311569698.4A CN117604603A (en) | 2023-11-22 | 2023-11-22 | Method for improving corrosion resistance of nickel-based alloy |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311569698.4A CN117604603A (en) | 2023-11-22 | 2023-11-22 | Method for improving corrosion resistance of nickel-based alloy |
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| CN117604603A true CN117604603A (en) | 2024-02-27 |
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| CN202311569698.4A Pending CN117604603A (en) | 2023-11-22 | 2023-11-22 | Method for improving corrosion resistance of nickel-based alloy |
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2023
- 2023-11-22 CN CN202311569698.4A patent/CN117604603A/en active Pending
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