Titanium alloy surface modification method based on nanoparticle reinforcement

Abstract

The invention discloses a titanium alloy surface modification method based on nanoparticle reinforcement, which comprises the following steps: placing a titanium alloy material in electrolyte containing hard nanoparticles, and forming a particle-reinforced oxide film on the surface of the titanium alloy through a micro-arc oxidation process to obtain a nanoparticle-reinforced titanium alloy material. Wherein long-chain alcohol ether polycarboxylic acid is introduced into the electrolyte to carry out surface modification on hard nano-particles contained in the electrolyte. According to the method, the hard nanoparticles modified by the anion active substance are introduced into the electrolyte, and the oxidation film layer with good wear resistance is formed on the surface of the titanium alloy by utilizing a micro-arc oxidation process, so that the comprehensive mechanical property of the surface film layer of the titanium alloy is remarkably improved, and the bonding strength of the film layer and a matrix material is optimized; and the service life of the coating is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of surface modification of metal materials, and relates to micro-arc oxidation surface modification of titanium alloy materials, and in particular to a method for performing micro-arc oxidation surface modification on titanium alloys by utilizing enhanced nanoparticles. Background Art

[0002] Titanium alloy is a metal material with high specific strength, low thermal expansion coefficient, excellent mechanical properties, corrosion resistance and good biocompatibility. It is widely used in aerospace, marine engineering, electric power, chemical industry, biomedicine, automobile manufacturing and metallurgy. However, due to the disadvantages of low hardness and poor surface wear resistance of titanium alloy, its service life and safety are significantly restricted. Therefore, it is of great significance to conduct in-depth research on the improvement of titanium alloy surface wear resistance.

[0003] At present, the methods to improve the wear resistance of materials are mainly focused on surface modification. Common surface modification technologies include thermal spraying, plasma spraying, vacuum coating, electroplating, chemical plating, micro-arc oxidation, laser cladding, vapor deposition and magnetron sputtering, etc. Among them, micro-arc oxidation has attracted widespread attention due to its advantages such as simple process, convenient operation, high efficiency, short time consumption, low requirements for experimental environment and relatively low cost.

[0004] Micro-arc oxidation (MAO), also known as plasma electrolytic oxidation (PEO), is developed from the anodizing technology, and the coating formed is superior to anodizing. Micro-arc oxidation mainly adjusts the matching of electrolyte and electrical parameters. Under the instantaneous high temperature and high pressure generated by arc discharge, a modified ceramic coating mainly composed of matrix metal oxide and supplemented by electrolyte components grows on the surface of valve metals such as aluminum, magnesium, titanium and their alloys. During the micro-arc oxidation process, the oxide film grows outward from the substrate, is tightly bonded to the substrate, and is not easy to fall off. At the same time, by adjusting the electrolyte composition and process parameters such as voltage and current, the composition and structure of the oxide film can be effectively controlled to achieve functional design. Therefore, the micro-arc oxidation process is expected to significantly improve the hardness and wear resistance of titanium alloy materials.

[0005] CN 114107881A discloses a surface treatment process for titanium alloy high-speed fan blades, which firstly performs plasma carburizing treatment on the titanium alloy high-speed fan blades, and then uses micro-arc oxidation process to prepare an oxide film layer. In the micro-arc oxidation process, B is added to the electrolyte. 4 C hard nanoparticles are tightly compounded with the oxide film layer, which can significantly improve the microhardness and wear resistance of the oxide film layer. However, since the movement of nanoparticles in the electrolyte is disordered, they do not show a tendency to migrate to the anode as a whole, resulting in low adhesion efficiency of nanoparticles on the oxide film; in addition, the nanoparticles attached to the oxide film are unevenly distributed, which leads to inconsistency in the performance of the film layer. Summary of the invention

[0006] The purpose of the present invention is to provide a method for surface modification of titanium alloy based on nanoparticle enhancement, by introducing hard nanoparticles modified by anionic active substances into an electrolyte, and using a micro-arc oxidation process to form an oxide film with good wear resistance on the surface of the titanium alloy.

[0007] The surface modification method of titanium alloy based on nanoparticle enhancement described in the present invention is to place the titanium alloy material in an electrolyte containing hard nanoparticles, and form a particle-enhanced oxide film on the surface of the titanium alloy through a micro-arc oxidation process to obtain a nanoparticle-enhanced titanium alloy material, wherein the present invention introduces long-chain alcohol ether polycarboxylic acid into the electrolyte to perform surface modification on the hard nanoparticles contained in the electrolyte.

[0008] The long-chain alcohol ether polycarboxylic acid is an anionic active substance, and its long-chain alcohol ether group provides good hydrophobicity. After the carboxylic acid group dissociates in water, a negative charge (COO - ) are adsorbed on the hard nanoparticles, which can make the surface of the hard nanoparticles negatively charged and move toward the anode under the action of voltage.

[0009] The hard nanoparticles added to the electrolyte can be any nanomaterial suitable for forming a ceramic oxide film coating on the surface of the titanium alloy using the micro-arc oxidation process, including but not limited to silicon carbide (SiC), silicon nitride (Si 3 N 4 )、ZrO 2 )、Alumina(Al 2 O 3 ) or a mixture of any proportion of any of them.

[0010] Furthermore, the specific steps of the titanium alloy surface modification method based on nanoparticle enhancement of the present invention include:

[0011] 1) Prepare electrolyte;

[0012] 2) Mix the hard nanoparticles and long-chain alcohol ether polycarboxylic acid in deionized water and add them into the electrolyte;

[0013] 3) Use titanium alloy as anode and stainless steel plate as cathode, connect the micro-arc oxidation power supply, put it into the electrolyte for micro-arc oxidation treatment to form a micro-arc oxidation film on the surface of titanium alloy.

[0014] Furthermore, the modification method of the present invention also includes pre-treating the titanium alloy material by surface grinding and cleaning.

[0015] The electrolyte used in the titanium alloy surface modification method of the present invention can be any one of an aluminate system electrolyte, a silicate system electrolyte, and a phosphate system electrolyte. The preferred electrolyte is sodium aluminate, sodium silicate or sodium phosphate, and the concentration is preferably 10 to 20 g / L.

[0016] Furthermore, sodium hydroxide may be added to the electrolyte to increase the conductivity of the electrolyte. The concentration of the sodium hydroxide is preferably 2 to 10 g / L.

[0017] In the titanium alloy surface modification method of the present invention, the concentration of hard nanoparticles added to the electrolyte is preferably controlled to be: SiC particle concentration 0.05-0.2wt%, Si 3 N 4 Particle concentration 0.1~0.3wt%, ZrO 2 Particle concentration is 0.05~0.25wt%,Al 2 O 3 Particle concentration 0.1~0.3wt%.

[0018] Furthermore, it is preferred that the concentration of the long-chain alcohol ether polycarboxylic acid added to the electrolyte be controlled to be 0.1 to 1 wt %.

[0019] The specific micro-arc oxidation process parameters in the titanium alloy surface modification method of the present invention are: the power supply adopts a constant current mode, and the current density is 5-20A / dm 2 , voltage 300~400V, frequency 300~1000Hz, oxidation time 25~45min.

[0020] The present invention adds long-chain alcohol ether polycarboxylic acid into the electrolyte, and the carboxylic acid group thereof dissociates in water to form a negative charge (COO - ) is uniformly adsorbed on the surface of hard nanoparticles, making the nanoparticles carry negative charges. Electrostatic repulsion occurs between charged nanoparticles, effectively avoiding the sedimentation or agglomeration of nanoparticles in the electrolyte, ensuring their uniform dispersion throughout the oxidation process, and improving the suspension and stability of nanoparticles in the electrolyte.

[0021] In addition, during the micro-arc oxidation process, the negatively charged nanoparticles evenly dispersed in the electrolyte are driven by the electric field force of micro-arc oxidation to move toward the anode, i.e., the surface of the titanium alloy, and gradually penetrate and embed into the oxide film layer on the surface of the titanium alloy. On the one hand, the nanoparticles are stably embedded in the microporous structure of the oxide film layer to form an enhanced reinforcing phase distribution, which greatly improves the hardness and wear resistance of the oxide film layer. On the other hand, it solves the problem of waste of raw materials caused by low particle attachment efficiency and inconsistent performance of the oxide film layer caused by uneven particle distribution.

[0022] In addition, the present invention can also achieve fine control over the uniformity of distribution and embedding depth of nanoparticles in the oxide film layer by precisely controlling the voltage and current density. Increasing the voltage will increase the electric field strength, allowing the nanoparticles to move toward the anode faster and embed into a deeper oxide layer; while low voltage will slow down the migration speed of the particles and reduce the discharge intensity, so that the particles can only be embedded on the surface of the film layer. The current density affects the rate of the oxidation reaction and the speed of film formation, and is another key parameter for controlling the uniformity of nanoparticle distribution and the number of embedded particles. Increasing the current density will increase the generation rate of the oxide film, causing the film layer to thicken rapidly, which is conducive to the rapid embedding of nanoparticles; reducing the current density can slow down the growth rate of the film layer, allowing the nanoparticles to have more time to be evenly distributed in the film layer during the oxidation process, thereby enhancing the uniformity of the embedding effect. Thus, by regulating the voltage and current density, the microstructure and composition distribution of the formed oxide film layer can meet the requirements of different working conditions and usage conditions.

[0023] Compared with the traditional micro-arc oxidation process, the surface modification method of the present invention not only significantly improves the wear resistance, scratch resistance and comprehensive mechanical properties of the titanium alloy surface film layer, but also optimizes the bonding strength between the film layer and the base material, and prolongs the service life of the coating. The modification method of the present invention has the advantages of strong versatility, simple operation, good repeatability, etc. It is suitable for industries with high requirements on material surface properties such as aerospace, marine engineering, and biomedicine, and provides an efficient, low-cost, and easy-to-operate solution for titanium alloy surface treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a SEM image of the micro-arc oxidation film obtained in Example 1.

[0025] Figure 2 This is the XRD diagram of the micro-arc oxidation film obtained in Example 1.

[0026] Figure 3 It is a polarization curve diagram of the corrosion test of the micro-arc oxidation film obtained in Examples 1 to 3 and the comparative example. Implementation

[0027] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of the present invention so that those skilled in the art can fully understand and utilize the present invention.

[0028] However, the present invention can be implemented in many other ways different from those described in the following embodiments, and those skilled in the art can also make similar improvements without violating the connotation of the present invention. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0029] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art. The terms used in the present invention specification are only for describing specific embodiments and are not intended to limit the present invention.

[0030] The term "and / or" used in the present invention includes any and all combinations of one or more of the associated listed items.

[0031] The terms "multiple", "multiple", "multiple times", "multiple groups", etc. used in the present invention, unless otherwise specified, refer to a quantity greater than or equal to 2; "above" includes the number itself, such as "more than two" includes two, three or more.

[0032] The term "preferred" used in the present invention is only used to describe an implementation method or example with better effects, and does not constitute a limitation on the protection scope of the present invention.

[0033] The production processes, experimental methods or detection methods involved in the embodiments of the present invention, unless otherwise specified, are all conventional methods in the prior art, and their names and / or abbreviations are all conventional names in the field, and are very clear and unambiguous in the relevant application fields. Technical personnel in the field can understand the conventional process steps and apply the corresponding equipment according to the names, and implement them according to conventional conditions or conditions recommended by the manufacturer, or refer to experimental methods known in the field.

[0034] The various instruments, equipment, raw materials or reagents used in the embodiments of the present invention are not particularly limited in terms of their sources, and are all conventional products that can be purchased through regular commercial channels, or can be prepared according to conventional methods well known to those skilled in the art.

[0035] The specific implementation steps of the titanium alloy surface modification method based on nanoparticle enhancement of the present invention include:

[0036] 1) Use sandpaper to smooth the surface of titanium alloy, use solvent ultrasonic cleaning to remove oil stains and dry it for later use;

[0037] 2) Prepare an electrolyte, add hard nanoparticles and long-chain alcohol ether polycarboxylic acid to obtain an electrolyte for micro-arc oxidation;

[0038] 3) Using the titanium alloy pretreated in step 1) as the anode and the stainless steel plate as the cathode, connect a micro-arc oxidation power supply, place in the micro-arc oxidation electrolyte obtained in step 2), set appropriate voltage and current, and perform micro-arc oxidation treatment under the action of an electric field to obtain a micro-arc oxidation film;

[0039] 4) Clean, dry and seal the titanium alloy after micro-arc oxidation treatment.

[0040] In a specific embodiment, the sandpaper polishing is to polish the surface of the titanium alloy successively with 400#, 800#, 1200#, and 2000# sandpapers to ensure a flat and smooth surface and remove the surface oxide scale and impurities; the solvent ultrasonic cleaning is to place the titanium alloy in an acetone or alcohol solution for ultrasonic cleaning for at least 15 minutes to remove oil stains and other pollutants; finally, the titanium alloy is rinsed with deionized water and dried to ensure no impurities on the surface, which helps the good adhesion between the titanium alloy substrate and the oxide film layer.

[0041] In a specific embodiment, the electrolyte can be any one of an aluminate system electrolyte, a silicate system electrolyte, or a phosphate system electrolyte, and the preferred main electrolyte is one of sodium aluminate, sodium silicate, or sodium phosphate.

[0042] In a more specific embodiment, the concentration of the electrolyte is preferably 10 - 20 g / L.

[0043] Furthermore, in the electrolyte of the specific embodiment, 2 - 10 g / L of sodium hydroxide can also be included to increase the conductivity of the electrolyte. In addition, other electrolytes can also be added to the electrolyte to obtain other desired properties.

[0044] In a specific embodiment, the hard nano - particles can be any one of SiC, Si 3 N 4 、ZrO 2 、Al 2 O 3 or any mixture of several of them in any proportion.

[0045] In a more specific embodiment, the concentration of SiC particles added to the electrolyte is preferably 0.05 - 0.2 wt%, Si 3 N 4 particle concentration is preferably 0.1 - 0.3 wt%, ZrO 2 particle concentration is preferably 0.05 - 0.25 wt%, Al 2 O 3 particle concentration is preferably 0.1 - 0.3 wt%.

[0046] In a specific embodiment, the concentration of the long - chain alcohol ether polycarboxylic acid added to the electrolyte is preferably 0.1 - 1 wt%.

[0047] In a specific embodiment, the hard nano - particles and the long - chain alcohol ether polycarboxylic acid can be mixed evenly in deionized water by ball - milling or mechanical stirring and then added to the electrolyte.

[0048] In a more specific embodiment, the ball - milling process is carried out in a planetary ball - mill for 6 - 8 hours, and the mechanical stirring is carried out in an automatic stirrer for 4 - 5 hours.

[0049] In a specific embodiment, the process parameters of the micro-arc oxidation treatment are: the power supply adopts a constant current mode, and the current density is 5 to 20A / dm 2 , voltage 300~400V, frequency 300~1000Hz, oxidation time 25~45min.

[0050] Unless otherwise specified, the amounts of raw material components and measurement parameters such as temperature and time involved in the embodiments of the present invention may have slight deviations within the range of weighing or measurement accuracy, and acceptable deviations caused by instrument testing accuracy or operating accuracy are allowed. Example

[0051] Example 1

[0052] 1) Titanium alloy pretreatment:

[0053] Take the prepared Ti-6Al-4V (TC4) titanium alloy sample and polish it with 400#, 800#, 1200# and 2000# sandpaper in turn to make its surface smooth. The polished sample is ultrasonically cleaned in acetone for 15 minutes to remove oil stains and blown dry with cold air.

[0054] 2) Preparation of electrolyte:

[0055] Weigh 20.5 g of sodium aluminate and 16.4 g of sodium hydroxide, add into 2 L of deionized water, and stir on a magnetic stirrer for 2 h to obtain a uniform solution.

[0056] Weigh 4.1 g of aluminum oxide (Al 2 O 3 ) nanoparticles and 6.15 g of long-chain alcohol ether polycarboxylic acid were added to 50 mL of deionized water and, after ball milling for 8 h, added to the above solution to obtain an electrolyte.

[0057] 3) Micro-arc oxidation:

[0058] Stainless steel was used as cathode and pretreated titanium alloy sample was used as anode. The sample was placed in electrolyte and the voltage was set to 380V and the current density was 15A / dm 2 , micro-arc oxidation at a frequency of 300 Hz for 45 min.

[0059] 4) Post-processing:

[0060] Take out the titanium alloy sample, rinse it with deionized water, dry it in a dust-free environment, and then seal it for storage.

[0061] In this embodiment, a higher voltage is set to enhance the electric field strength, which drives the negatively charged particles to migrate rapidly to the anode and deeply embed into the film layer. The higher current density increases the growth rate of the oxide film. At the same time, the low frequency causes the micro-arc to generate higher temperature and pressure, which is conducive to deeper embedding of the nanoparticles. The longer oxidation time ensures the formation of a thicker coating and the embedding of a sufficient number of nanoparticles.

[0062] Based on the higher micro arc discharge generated by high voltage and high current density, Figure 1 It can be seen that the surface of the micro-arc oxidation film obtained in Example 1 has many tiny holes with a pore size of about 1 to 5 μm, indicating that the added Al 2 O 3 The particles seal the micro-arc oxidation film and reduce the porosity of the film.

[0063] from Figure 2 It can be seen from the XRD spectrum that the micro-arc oxidation film is mainly composed of anatase TiO 2 and Al 2 O 3 composition.

[0064] Therefore, this embodiment generates a wear-resistant coating with high hardness and deep embedding on the surface of the titanium alloy sample, which is suitable for high wear environment.

[0065] Example 2

[0066] 1) Titanium alloy pretreatment:

[0067] Take the commercially pure Ti (TA1) titanium alloy sample prepared in advance and polish it with 400#, 800#, 1200# and 2000# sandpaper in sequence to make its surface smooth. The polished sample is ultrasonically cleaned in alcohol for 15 minutes to remove oil stains and blown dry with cold air.

[0068] 2) Preparation of electrolyte:

[0069] Weigh 30.75 g of sodium silicate and 10.25 g of sodium hydroxide, add them to 2 L of deionized water, and stir on a magnetic stirrer for 2 h to obtain a uniform solution.

[0070] Weigh 2.05 g of silicon nitride (Si 3 N 4 ) nanoparticles and 5.125 g of long-chain alcohol ether polycarboxylic acid were added to 50 mL of deionized water and mechanically stirred for 4 h before being added to the above solution to obtain an electrolyte.

[0071] 3) Micro-arc oxidation:

[0072] Stainless steel was used as cathode and pretreated titanium alloy sample was used as anode. The sample was placed in electrolyte and the voltage was set to 300V and the current density was 5A / dm 2, micro-arc oxidation at a frequency of 1000 Hz for 20 min.

[0073] 4) Post-processing:

[0074] Take out the titanium alloy sample, rinse it with deionized water, dry it in a dust-free environment, and then seal it for storage.

[0075] This embodiment maintains a low electric field strength, so that the nanoparticles are shallowly embedded in the surface of the film layer to form a uniformly distributed thin film. The lower current density slows down the growth rate of the film layer and ensures the density of the film layer. At the same time, high frequency produces small and uniform micro-arc discharges to reduce surface roughness and form a thinner and more uniform coating with a shorter oxidation time.

[0076] Therefore, this embodiment generates a thin coating with a smooth surface and uniformly distributed nanoparticles on the surface of the titanium alloy sample, which is suitable for applications with high requirements for surface smoothness.

[0077] Example 3

[0078] 1) Titanium alloy pretreatment:

[0079] Take the prepared Ti-13Nb-13Zr (TC26) titanium alloy sample and polish it with 400#, 800#, 1200# and 2000# sandpaper in turn to make its surface smooth. The polished sample is ultrasonically cleaned in acetone for 15 minutes to remove oil stains and blown dry with cold air.

[0080] 2) Preparation of electrolyte:

[0081] Weigh 41 g of sodium phosphate and 10.25 g of sodium hydroxide, add into 2 L of deionized water, and stir on a magnetic stirrer for 2 h to obtain a uniform solution.

[0082] 3.075 g of silicon carbide (SiC) nanoparticles and 6.15 g of long-chain alcohol ether polycarboxylic acid were weighed and added to 50 mL of deionized water. After ball milling for 6 h, the mixture was added to the above solution to obtain an electrolyte.

[0083] 3) Micro-arc oxidation:

[0084] Stainless steel was used as cathode and pretreated titanium alloy sample was used as anode. The sample was placed in electrolyte and the voltage was set to 340V and the current density was 10A / dm 2 , micro-arc oxidation at a frequency of 600 Hz for 30 min.

[0085] 4) Post-processing:

[0086] Take out the titanium alloy sample, rinse it with deionized water, dry it in a dust-free environment, and then seal it for storage.

[0087] This embodiment ensures a moderate electric field strength so that the SiC particles are moderately embedded in the film layer, and a medium-intensity current density ensures uniform growth of the film layer; a medium frequency forms a micro-arc discharge of moderate size, which not only enhances the hardness of the coating but also keeps the surface relatively smooth, and a moderate oxidation time is used to generate a dense oxide film layer with a certain thickness and wear resistance, thereby ensuring that nanoparticles are uniformly embedded on the surface of the titanium alloy sample and a dense protective layer with medium thickness and hardness is generated, which is suitable for applications with medium wear and corrosion resistance requirements.

[0088] Comparative Example

[0089] 1) Titanium alloy pretreatment:

[0090] Take the prepared Ti-6Al-4V (TC4) titanium alloy sample and polish it with 400#, 800#, 1200# and 2000# sandpaper in turn to make its surface smooth. The polished sample is ultrasonically cleaned in acetone for 15 minutes to remove oil stains and blown dry with cold air.

[0091] 2) Preparation of electrolyte:

[0092] 20.5 g of sodium aluminate, 16.4 g of sodium hydroxide and 4.1 g of aluminum oxide nanoparticles were weighed, added into 2 L of deionized water, and stirred on a magnetic stirrer for 2 h to obtain an electrolyte.

[0093] 3) Micro-arc oxidation:

[0094] Stainless steel was used as cathode and pretreated titanium alloy sample was used as anode. The sample was placed in electrolyte and the voltage was set to 380V and the current density was 15A / dm 2 , micro-arc oxidation at a frequency of 300 Hz for 45 min.

[0095] 4) Post-processing:

[0096] Take out the titanium alloy sample, rinse it with deionized water, dry it in a dust-free environment, and then seal it for storage.

[0097] Figure 3 The polarization curves of the micro-arc oxidation films obtained by the corrosion resistance tests on different embodiments and comparative examples are further shown. By observing these curves, the corrosion resistance of embodiments 1 to 3 and the comparative example can be clearly compared.

[0098] The micro-arc oxidation film of Example 1 exhibits the lowest corrosion current density and the highest corrosion potential, indicating that it has the best corrosion resistance. This excellent corrosion resistance is mainly due to its dense oxide film structure and the deeply embedded Al 2 O 3 Nanoparticles enhance the film's resistance to chemical attack. In addition, higher hardness and less roughness reduce the intrusion path of corrosive media.

[0099] The micro-arc oxidation film of Example 2 also exhibits significant corrosion resistance, but is slightly inferior to that of Example 1. The reason is that Si 3 N 4 The nanoparticles are mainly distributed in the surface area of ​​the oxide film. The film thickness is relatively thin. Although the density is good, the surface is susceptible to initial erosion by the corrosive medium. The lower corrosion current density indicates that it can still provide effective corrosion protection.

[0100] The micro-arc oxidation film of Example 3 exhibits moderate corrosion resistance, which is better than the comparative example, but not as good as that of Examples 1 and 2. This result is related to the moderate embedding of SiC nanoparticles, whose distribution uniformity and embedding depth are not enough to form a protective film layer with high density like that of Example 1, but whose thickness is moderate and can provide certain anti-corrosion protection.

[0101] In Comparative Example 1, the nanoparticles were not treated, and the polarization curve of the micro-arc oxidation film showed a higher corrosion current density and a lower corrosion potential, indicating that its corrosion resistance was significantly lower than that of Examples 1 to 3. This is because the unmodified nanoparticles have poor suspension in the electrolyte, resulting in uneven distribution in the oxide film layer, and may even form defects in certain areas, reducing the protective performance of the film layer.

[0102] Through the analysis of polarization curves of different embodiments and comparative examples, it can be seen that after the nanoparticles are treated with long-chain alcohol ether polycarboxylic acid, the corrosion resistance of the micro-arc oxidation film is significantly improved. In particular, embodiment 1 has the best film density and hardness, showing the strongest corrosion resistance and is suitable for harsh corrosive environments.

[0103] Table 1 below provides the mechanical properties of the micro-arc oxidation films obtained in Examples 1 to 3 and the comparative example.

[0104]

[0105] In Table 1, the micro-arc oxidation parameters of Example 1 and Comparative Example 1 are the same, and the only difference is that long-chain alcohol ether polycarboxylic acid is added in Example 1. The results show that the hardness, surface roughness and wear resistance of the oxide film of Example 1 are significantly better than those of Comparative Example 1, indicating that after the nanoparticle modification, the particle suspension performance is significantly improved, and the nanoparticles are more stable and evenly distributed during the film formation process.

[0106] Furthermore, although the mechanical properties and surface roughness of Examples 2 and 3 are not as good as those of Example 1, they are better than those of Comparative Example 1, indicating that the addition of long-chain alcohol ether polycarboxylic acid can significantly optimize the suspension of nanoparticles in the electrolyte and reduce the agglomeration of particles. In addition, the negative ions (COO -) adsorbed on the surface of nanoparticles, making the particles negatively charged, and effectively controlling the directional migration of particles to the anode under the action of the electric field, thereby ensuring the uniform distribution of particles in the oxide film and achieving dense bonding. Therefore, by adding long-chain alcohol ether polycarboxylic acid, the stability and distribution of nanoparticles can be effectively regulated, promoting the uniform participation of particles in film formation, and optimizing the comprehensive performance of micro-arc oxidation film.

[0107] The technical features of the above embodiments of the present invention can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of the description of the present invention.

[0108] The above embodiments express several more specific and detailed implementation methods of the present invention, but they should not be understood as limiting the scope of protection of the present invention. It should be pointed out that ordinary technicians in this field can also make several substitutions, deformations or improvements without departing from the principles and purpose of the present invention, which should all be included in the scope of protection of the present invention.

Claims

1. A method for surface modification of a titanium alloy based on nanoparticle enhancement, which is to place a titanium alloy material in an electrolyte containing hard nanoparticles, and form a particle-enhanced oxide film on the surface of the titanium alloy by a micro-arc oxidation process to obtain a nanoparticle-enhanced titanium alloy material, wherein: Long-chain alcohol ether polycarboxylic acid is introduced into the electrolyte to modify the surface of the hard nanoparticles contained in the electrolyte.

2. The titanium alloy surface modification method according to claim 1, characterized in that The hard nanoparticles added to the electrolyte are any one of silicon carbide, silicon nitride, zirconium oxide, and aluminum oxide, or a mixture of any proportion of the above.

3. The titanium alloy surface modification method according to claim 1, comprising: 1) Prepare electrolyte; 2) Mix the hard nanoparticles and long-chain alcohol ether polycarboxylic acid in deionized water and add them into the electrolyte; 3) Use titanium alloy as anode and stainless steel plate as cathode, connect the micro-arc oxidation power supply, put it into the electrolyte for micro-arc oxidation treatment, and form a micro-arc oxidation film on the surface of the titanium alloy.

4. The titanium alloy surface modification method according to claim 3, characterized in that The method also includes surface grinding and cleaning pretreatment of the titanium alloy material.

5. The titanium alloy surface modification method according to claim 1, 2 or 3, characterized in that The electrolyte is any one of an aluminate electrolyte, a silicate electrolyte, and a phosphate electrolyte.

6. The titanium alloy surface modification method according to claim 5, characterized in that The electrolyte in the electrolyte is sodium aluminate, sodium silicate or sodium phosphate, with a concentration of 10-20 g / L.

7. The titanium alloy surface modification method according to claim 5, characterized in that Sodium hydroxide with a concentration of 2 to 10 g / L is also added to the electrolyte.

8. The titanium alloy surface modification method according to claim 3 is characterized in that the concentration of hard nanoparticles added to the electrolyte is: SiC particle concentration 0.05-0.2wt%, Si3N4 particle concentration 0.1-0.3wt%, ZrO2 particle concentration 0.05-0.25wt%, Al2O3 particle concentration 0.1-0.3wt%.

9. The titanium alloy surface modification method according to claim 3, characterized in that The concentration of the long-chain alcohol ether polycarboxylic acid added to the electrolyte is 0.1-1 wt %.

10. The titanium alloy surface modification method according to claim 3, characterized in that The micro-arc oxidation process parameters are: the power supply adopts constant current mode, and the current density is 5-20A / dm 2 , voltage 300~400V, frequency 300~1000Hz, oxidation time 25~45min.

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