CN111826606A - Aluminum and aluminum alloy surface plasma oxidation method - Google Patents

Aluminum and aluminum alloy surface plasma oxidation method Download PDF

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Publication number
CN111826606A
CN111826606A CN201910330677.4A CN201910330677A CN111826606A CN 111826606 A CN111826606 A CN 111826606A CN 201910330677 A CN201910330677 A CN 201910330677A CN 111826606 A CN111826606 A CN 111826606A
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arc
oxidation
argon
aluminum
matrix
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赵彦辉
刘忠海
刘占奇
于宝海
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Institute of Metal Research of CAS
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    • CCHEMISTRY; METALLURGY
    • C23COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23CCOATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/36Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases using ionised gases, e.g. ionitriding

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physical Vapour Deposition (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Abstract

The invention belongs to the technical field of surface modification of metal materials, and particularly relates to a method for performing plasma oxidation on the surface of aluminum and aluminum alloy. The method is completed by adopting an Arc Enhanced Glow Discharge (AEGD) technology, electron current is generated through arc discharge, then electrons collide with gas such as oxygen and the like to be ionized, oxygen plasma is generated, a positive bias electric field is applied to the surface of a matrix, glow discharge is generated, and negatively charged oxygen ions are attracted to the surface of the matrix to carry out oxidation reaction, so that the aluminum oxide protective film layer is generated. Compared with the traditional micro-arc oxidation and anodic oxidation technologies, the method has the advantages of no environmental pollution and the like, and can effectively improve the pitting corrosion resistance of the surface of the aluminum alloy.

Description

Aluminum and aluminum alloy surface plasma oxidation method
The technical field is as follows:
the invention belongs to the technical field of surface modification of metal materials, and particularly relates to a method for performing plasma oxidation on the surface of aluminum and aluminum alloy.
Background art:
the aluminum and aluminum alloy material has a series of advantages of small relative density, high specific strength, good plasticity, excellent electric and heat conducting properties, easy processing and forming, low price and the like, is widely applied to a plurality of fields of aerospace, ship manufacturing, weapon industry, light industry building materials and the like, and is one of key materials with economic value and commercial application significance. In particular, aluminum alloy materials can be combined with oxygen in the air in the atmosphere to form a thin oxide film on the surface of the alloy. However, the oxide film is thin, generally only 2nm and has a porous structure, and under the condition of seawater or marine environment, chloride ions easily penetrate through the oxide film to cause pitting corrosion, which is often difficult to meet the requirements. Therefore, the surface of the alloy is often treated by an electrochemical means, and a layer of uniform, continuous and dense porous alumina film is formed on the surface of the aluminum alloy, so that the corrosion resistance and the wear resistance of the surface of the material are improved.
Although some surface treatment methods (such as anodic oxidation, chemical oxidation, micro-arc oxidation and the like) are widely applied, the oxide films prepared by the technologies have more defects and have larger environmental pollution. With the development of society, the requirements for aluminum alloy quality and environmental protection and energy conservation are higher and higher, and people begin to adopt some vacuum treatment methods, such as: glow discharge such as ion nitriding, ion oxygen diffusion and ion implantation is the core method. Such as: oxidation of Fu-Hsing Li, et Al, Taiwan, by a 13.6MHz radio frequency ion device for 2H produced a crystalline alumina layer with a thickness of about 60nm on the surface of aluminum (Lu F H, Tsai H D, Chieh YC. plasma oxidation of Al thin Films on Si substrates, thin Solid Films, 2008, 516(8): 1871-1876). Raveh et al in Germany used microwave ion oxidation Technology to prepare amorphous alumina layers of 20nm thickness (Raveh A, Tsalaret Z K, Grossman E. surface catalysis of in layers of aluminum oxides. surface and Coatings Technology,1997,88(1): 103-.
In China, the hollow cathode discharge auxiliary ion oxidation treatment of aluminum alloy (Liyan, Zhang Mianwu, Xuhui, Qinwei, Zhao Xiangjin and Wangshou, research on the hollow cathode discharge auxiliary ion oxidation technology of aluminum alloy, school of tobacco station university (Nature science and engineering edition), 2014,27(4):271 plus 274) is adopted to prepare a compact and smooth oxide layer (Al) with the thickness of 20-500 nm2O3). The untreated and ion oxidized samples were subjected to a soaking corrosion test in a 3.5 wt% NaCl solution, after 20 days of soaking, the untreated samples were severely corroded, while the oxidized sample surface was not significantly corroded. In general, the corrosion resistance of the aluminum alloy can be effectively improved after the ion oxygen permeation, but the thickness of the oxide layer is still thin, and the thickness of the oxide layer is still to be improved.
Disclosure of Invention
Aiming at the defects of the existing aluminum and aluminum alloy oxidation technology, the invention aims to provide a method for carrying out plasma oxidation on the surface of aluminum and aluminum alloy, which can effectively improve the corrosion resistance of the aluminum alloy and simultaneously improve the thickness of an oxidation layer.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a plasma oxidation method for the surface of aluminum and aluminum alloy adopts an arc enhanced glow discharge technology to realize the plasma oxidation of the surface of the aluminum and aluminum alloy.
According to the aluminum and aluminum alloy surface plasma oxidation method, when an arc enhanced glow discharge technology is adopted, an auxiliary anode is arranged on the outer side of an arc cathode target, and water is introduced to cool the auxiliary anode; the auxiliary anode adopts oxygen-free copper and is connected with the arc source cathode.
The aluminum and aluminum alloy surface plasma oxidation method adopts the arc enhanced glow discharge technology to carry out the plasma oxidation process, wherein the matrix is connected with the positive pole of a bias power supply, and the wall of the vacuum chamber is connected with the negative pole of the bias power supply.
The aluminum and aluminum alloy surface plasma oxidation method comprises the following specific steps:
(1) pre-cleaning a substrate: carrying out ultrasonic treatment on the surface of the matrix in an alcohol solution for 1-30 minutes after sand blasting, drying the matrix by hot air, and then putting the matrix on a workpiece rack in a vacuum chamber for waiting for treatment;
(2) argon ion bombardment: adopting pure titanium target, when the vacuum degree in the vacuum chamber reaches 1X 10-3Pa~1×10-2Heating the vacuum chamber to 200-500 ℃ when Pa is needed; introducing argon into the vacuum chamber, wherein the pressure of the argon is controlled to be 0.1-5 Pa; meanwhile, starting an arc source of the pure titanium target, wherein the arc current is 60-150A, the pure titanium target generates electron current after arc discharge, the argon is ionized, the matrix is subjected to pulse negative bias in a range of-400V to-1500V, the bias duty ratio is in a range of 30-90%, the argon is subjected to glow discharge, and the matrix is subjected to glow cleaning for 10-120 minutes;
(3) plasma oxidation: adopting a pure titanium target, adjusting the argon pressure to be within the range of 0.1-5 Pa, introducing oxygen simultaneously, applying pulse positive bias voltage of 10-500V to the matrix, wherein the argon flow is within the range of 100-1000 sccm, the oxygen flow is within the range of 5-50% of the argon flow, and the bias voltage duty ratio is within the range of 10-80%; adjusting the arc current to be 60-150A, and the oxidation time to be 10-300 minutes;
(4) and after the oxidation is finished, stopping arc, stopping the pulse bias of the substrate, stopping introducing argon and oxygen, continuing vacuumizing, cooling the workpiece to be below 100 ℃ along with the furnace, opening the vacuum chamber, taking out the workpiece, and finishing the oxidation process.
According to the aluminum and aluminum alloy surface plasma oxidation method, after the oxidation process is finished, the thickness of the oxide layer ranges from 0.01 to 2 micrometers.
The design idea of the invention is as follows:
the invention utilizes arc discharge enhancement to further improve the plasma density on the basis of glow discharge, thereby improving the thickness of the oxide layer. The method is completed by adopting an Arc Enhanced Glow Discharge (AEGD) technology, electron current is generated through arc discharge, then electrons collide with gases such as oxygen and the like to be ionized to generate oxygen plasma, a positive bias electric field is applied to the surface of a matrix to generate glow discharge, and negatively charged oxygen ions are attracted to the surface of the matrix to carry out oxidation reaction, so that an aluminum oxide protective film layer is generated.
Compared with the prior art, the invention has the advantages and beneficial effects that:
1. the invention adopts the electric Arc Enhanced Glow Discharge (AEGD) technology to realize plasma oxidation on the surface of aluminum and aluminum alloy, and compared with anodic oxidation and micro-arc oxidation, the invention has the advantages of no pollution to the environment, high oxidation speed, thicker thickness of the obtained oxide layer and the like.
2. The oxide layer prepared by the method can effectively improve the pitting corrosion resistance of the aluminum alloy in the marine environment.
3. The invention sets an auxiliary anode outside the arc cathode target, and cools the auxiliary anode through water, the auxiliary anode has the following functions: negatively charged electrons are attracted, and the gas is ionized by the collision of the electrons with gas molecules.
The specific implementation mode is as follows:
the present invention will be described in further detail below with reference to examples.
Example 1
In this example, pure aluminum was used as the base material, and the sample piece had a size of 20mm × 10mm × 10mm and an oxidized surface size of 20mm × 10 mm. Before oxidation, the surface of the substrate is ground and polished, ultrasonically cleaned in alcohol solution for 10 min, dried and then put on a workpiece rack in a vacuum chamber until the vacuum degree in the vacuum chamber reaches 4X 10-3Heating a vacuum chamber to 350 ℃ when Pa is needed, opening a gas mass flow controller, introducing argon into the vacuum chamber, setting the flow of the argon to be 500sccm, controlling the air pressure to be 3.0Pa, simultaneously starting a pure titanium target arc source, wherein the arc current is 80A, generating electron current after the pure titanium target generates arc discharge, ionizing the argon, adding pulse negative bias to a substrate to be-700V, and the bias duty ratio to be 70%, so that the argon generates glow discharge, and performing glow cleaning on the substrate for 40 minutes; then adjusting the pressure of argon to be 2.0Pa, introducing oxygen at the same time, wherein the flow of the oxygen is 20% of the flow of the argon, applying a pulse positive bias voltage of 200V to the substrate, and the bias voltage duty ratio is 30%; adjusting the arc current to 80A and the oxidation time to 90 minutes; and after the oxidation is finished, stopping arc, stopping pulse bias of the substrate, stopping introducing gas, continuing vacuumizing, cooling the workpiece to be below 100 ℃ along with the furnace, opening the vacuum chamber, taking out the workpiece, and finishing the oxidation process.
The obtained oxide layer is silver gray in appearance, and the thickness of the oxide layer is 0.4 micron as tested by a scanning electron microscope.
Example 2
In this example, an aluminum alloy (grade 2024) was used as a base material, and the sample size was 20mm × 10mm × 10mm, and the oxidized surface size was 20mm × 10 mm. Before oxidation, the surface of the substrate is ground and polished, ultrasonically cleaned in alcohol solution for 15 min, dried and then put on a workpiece rack in a vacuum chamber until the vacuum degree in the vacuum chamber reaches 2X 10-3Heating a vacuum chamber to 450 ℃ when Pa is needed, opening a gas mass flow controller, introducing argon into the vacuum chamber, setting the flow of the argon to be 350sccm, controlling the air pressure to be 2.0Pa, simultaneously starting a pure titanium target arc source, wherein the arc current is 90A, generating electron current after the pure titanium target generates arc discharge, ionizing the argon, adding pulse negative bias to a substrate to be-800V, and the bias duty ratio to be 60%, so that the argon generates glow discharge, and performing glow cleaning on the substrate for 60 minutes; then adjusting the argon pressure to1.5Pa, and introducing oxygen at the same time, wherein the oxygen flow is 15% of the argon flow, a pulse positive bias voltage of 150V is applied to the matrix, and the bias duty ratio is 25%; adjusting the arc current to 80A and the oxidation time to 120 minutes; and after the oxidation is finished, stopping arc, stopping pulse bias of the substrate, stopping introducing gas, continuing vacuumizing, cooling the workpiece to be below 100 ℃ along with the furnace, opening the vacuum chamber, taking out the workpiece, and finishing the oxidation process.
The obtained oxide layer is silver gray in appearance, and the thickness of the oxide layer is 0.5 micron as tested by a scanning electron microscope.
Example 3
In this example, an aluminum alloy (No. 6061) was used as a base material, and the sample size was 20mm × 10mm × 10mm, and the oxidized surface size was 20mm × 10 mm. Before oxidation, the surface of the substrate is ground and polished, ultrasonically cleaned in alcohol solution for 20 min, dried and then put on a workpiece rack in a vacuum chamber until the vacuum degree in the vacuum chamber reaches 6X 10-3When Pa is needed, heating a vacuum chamber to 400 ℃, opening a gas mass flow controller, introducing argon into the vacuum chamber, setting the flow of the argon to be 600sccm, controlling the air pressure to be 3.5Pa, simultaneously starting a pure titanium target arc source, wherein the arc current is 100A, generating electron current after the pure titanium target generates arc discharge, ionizing the argon, adding pulse negative bias to the substrate to be-600V, and the bias duty ratio to be 80%, so that the argon generates glow discharge, and performing glow cleaning on the substrate for 60 minutes; then adjusting the pressure of argon to be 2.5Pa, introducing oxygen at the same time, wherein the flow of the oxygen is 20% of the flow of the argon, applying a pulse positive bias voltage of 200V to the substrate, and the duty ratio of the bias voltage is 20%; adjusting the arc current to 90A and the oxidation time to 180 minutes; and after the oxidation is finished, stopping arc, stopping pulse bias of the substrate, stopping introducing gas, continuing vacuumizing, cooling the workpiece to be below 100 ℃ along with the furnace, opening the vacuum chamber, taking out the workpiece, and finishing the oxidation process.
The appearance of the obtained oxide layer is silver gray, and the thickness of the oxide layer is 0.9 micron by a scanning electron microscope test.
Example 4
In this example, an aluminum alloy (grade 7075) was used as a base material, and the sample size was 20mm × 10mm × 10mm, and the oxidized surface size was 20mm × 10 mm. Before oxidation, the surface of the substrate is ground and polished in alcoholUltrasonic cleaning in solution for 25 min, drying, placing on a workpiece holder in a vacuum chamber until the vacuum degree in the vacuum chamber reaches 2 × 10-3Heating a vacuum chamber to 500 ℃ when Pa is needed, opening a gas mass flow controller, introducing argon into the vacuum chamber, setting the flow of the argon to be 300sccm, controlling the air pressure to be 1.8Pa, simultaneously starting a pure titanium target arc source, wherein the arc current is 100A, generating electron current after the pure titanium target generates arc discharge, ionizing the argon, adding pulse negative bias to a substrate to be-900V, and the bias duty ratio to be 70%, so that the argon generates glow discharge, and performing glow cleaning on the substrate for 60 minutes; then adjusting the pressure of argon to be 1.8Pa, introducing oxygen at the same time, wherein the flow of the oxygen is 25% of the flow of the argon, applying a pulse positive bias voltage of 250V to the substrate, and the bias voltage duty ratio is 30%; adjusting the arc current to 70A and the oxidation time to 150 minutes; and after the oxidation is finished, stopping arc, stopping pulse bias of the substrate, stopping introducing gas, continuing vacuumizing, cooling the workpiece to be below 100 ℃ along with the furnace, opening the vacuum chamber, taking out the workpiece, and finishing the oxidation process.
The obtained oxide layer is silver gray in appearance, and the thickness of the oxide layer is 0.8 micron as tested by a scanning electron microscope.
The embodiment result shows that compared with the traditional micro-arc oxidation and anodic oxidation technologies, the method for carrying out plasma oxidation on the surface of the aluminum and the aluminum alloy has the advantages of no environmental pollution and the like, and can effectively improve the pitting corrosion resistance of the surface of the aluminum alloy.

Claims (5)

1. The plasma oxidation method for the surface of the aluminum and the aluminum alloy is characterized in that the plasma oxidation of the surface of the aluminum and the aluminum alloy is realized by adopting an arc enhanced glow discharge technology.
2. The method for surface plasma oxidation of aluminum or an aluminum alloy according to claim 1, wherein an auxiliary anode is provided outside the arc cathode target and water is introduced to the auxiliary anode for cooling when the arc-enhanced glow discharge technique is employed; the auxiliary anode adopts oxygen-free copper and is connected with the arc source cathode.
3. The method of claim 1 wherein the substrate is connected to a positive electrode of a bias power supply and the vacuum chamber wall is connected to a negative electrode of the bias power supply during plasma oxidation by arc enhanced glow discharge.
4. A method for plasma oxidation of an aluminium and aluminium alloy surface according to any one of claims 1 to 3, characterised by the specific steps of:
(1) pre-cleaning a substrate: carrying out ultrasonic treatment on the surface of the matrix in an alcohol solution for 1-30 minutes after sand blasting, drying the matrix by hot air, and then putting the matrix on a workpiece rack in a vacuum chamber for waiting for treatment;
(2) argon ion bombardment: adopting pure titanium target, when the vacuum degree in the vacuum chamber reaches 1X 10-3Pa~1×10-2Heating the vacuum chamber to 200-500 ℃ when Pa is needed; introducing argon into the vacuum chamber, wherein the pressure of the argon is controlled to be 0.1-5 Pa; meanwhile, starting an arc source of the pure titanium target, wherein the arc current is 60-150A, the pure titanium target generates electron current after arc discharge, the argon is ionized, the matrix is subjected to pulse negative bias in a range of-400V to-1500V, the bias duty ratio is in a range of 30-90%, the argon is subjected to glow discharge, and the matrix is subjected to glow cleaning for 10-120 minutes;
(3) plasma oxidation: adopting a pure titanium target, adjusting the argon pressure to be within the range of 0.1-5 Pa, introducing oxygen simultaneously, applying pulse positive bias voltage of 10-500V to the matrix, wherein the argon flow is within the range of 100-1000 sccm, the oxygen flow is within the range of 5-50% of the argon flow, and the bias voltage duty ratio is within the range of 10-80%; adjusting the arc current to be 60-150A, and the oxidation time to be 10-300 minutes;
(4) and after the oxidation is finished, stopping arc, stopping the pulse bias of the substrate, stopping introducing argon and oxygen, continuing vacuumizing, cooling the workpiece to be below 100 ℃ along with the furnace, opening the vacuum chamber, taking out the workpiece, and finishing the oxidation process.
5. The method of claim 4, wherein the oxide layer has a thickness of 0.01 to 2 μm after the oxidation process.
CN201910330677.4A 2019-04-23 2019-04-23 Aluminum and aluminum alloy surface plasma oxidation method Pending CN111826606A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114369790A (en) * 2021-11-30 2022-04-19 华中光电技术研究所(中国船舶重工集团公司第七一七研究所) Aluminum hyper-hemisphere manufacturing process

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Publication number Priority date Publication date Assignee Title
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KR20120116558A (en) * 2011-04-13 2012-10-23 바코스 주식회사 High speed film forming apparatus, and film forming method using the same
WO2013165036A1 (en) * 2012-05-02 2013-11-07 바코스 주식회사 High-speed film-forming device and film-forming method using same
CN105177493A (en) * 2015-09-22 2015-12-23 华南理工大学 Electric arc plasma auxiliary low-voltage nitriding method for surface of hot-working die

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101709449A (en) * 2009-11-24 2010-05-19 大连海事大学 Surface oxidation treatment device and method of aluminum alloy
KR20120116558A (en) * 2011-04-13 2012-10-23 바코스 주식회사 High speed film forming apparatus, and film forming method using the same
WO2013165036A1 (en) * 2012-05-02 2013-11-07 바코스 주식회사 High-speed film-forming device and film-forming method using same
CN105177493A (en) * 2015-09-22 2015-12-23 华南理工大学 Electric arc plasma auxiliary low-voltage nitriding method for surface of hot-working die

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Title
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114369790A (en) * 2021-11-30 2022-04-19 华中光电技术研究所(中国船舶重工集团公司第七一七研究所) Aluminum hyper-hemisphere manufacturing process

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Application publication date: 20201027