A method for preparing a titanium alloy micro-arc oxidation wear-resistant and corrosion-resistant film layer for a chemical reactor

Abstract

The application discloses a preparation method of a titanium alloy micro-arc oxidation wear-resistant and corrosion-resistant film layer for a chemical reactor and belongs to the technical field of alloy surface modification. The preparation method comprises the following steps: substrate pretreatment, micro-arc oxidation and cleaning and drying. The surface of a titanium alloy substrate is polished, cleaned and dried; the pretreated titanium alloy substrate is placed in an electrolyte prepared from aluminate, and a wear-resistant and corrosion-resistant ceramic film layer is prepared by adopting micro-arc oxidation treatment; and the film-coated titanium alloy after the micro-arc oxidation treatment is cleaned and dried. By adopting the micro-arc oxidation process under the aluminate electrolyte system, the ceramic film layer with good compactness, corrosion resistance and wear resistance can be prepared on the surface of the titanium alloy for the chemical reactor, and the working efficiency and safety of the titanium alloy in the application field of the chemical reactor are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of alloy surface modification technology, specifically relating to a method for preparing a wear-resistant and corrosion-resistant micro-arc oxidation film layer of titanium alloy for chemical reactors. Background Technology

[0002] Micro-arc oxidation (MAO) is a technique for in-situ growth of ceramic films on non-ferrous metal surfaces. Using titanium alloys as the substrate, MAO surface modification can yield MAO ceramic layers with good toughness, corrosion resistance, and wear resistance. Because MAO is in-situ, the film-substrate bond is good, and surface smoothness can be improved over a wide range by adjusting process parameters. However, many parameters affect the quality of titanium alloy MAO films, and the film formation mechanism and precise control of film properties, size, and morphology under the interaction of these parameters still lack a systematic solution. This invention addresses the galvanic corrosion problem of titanium alloys used in chemical reactors by proposing a MAO process in an aluminate electrolyte system, effectively improving the efficiency and safety of titanium alloys in chemical reactor applications. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a wear-resistant and corrosion-resistant titanium alloy micro-arc oxidation film for chemical reactors.

[0004] The objective of this invention is achieved as follows: the method for preparing the wear-resistant and corrosion-resistant titanium alloy micro-arc oxidation film for chemical reactors includes substrate pretreatment, micro-arc oxidation, and cleaning and drying steps, specifically including: A. Substrate pretreatment: Polish, clean, and dry the surface of the titanium alloy substrate; B. Micro-arc oxidation: The pretreated titanium alloy substrate is placed in an electrolyte prepared from aluminate, and a wear-resistant and corrosion-resistant ceramic film is prepared by micro-arc oxidation. C. Cleaning and drying: Clean and dry the coated titanium alloy after micro-arc oxidation treatment.

[0005] Compared with existing technologies, the significant progress and beneficial effects of the technical solution described in this invention are reflected in the following: the wear-resistant and corrosion-resistant film layer is prepared by a micro-arc oxidation process in an aluminate electrolyte system. The aluminate electrolyte contains NaAlO2, NaOH, NaCl, and citric acid. The method includes pretreatment of the TA10 alloy sample, preparation of the aluminate electrolyte, and micro-arc oxidation coating process. First, the TA10 alloy sample is polished with 800-6000# metallographic sandpaper, then polished with 5-0.5μm diamond polishing paste, then washed with 10-15g / L NaOH alkali for 6-8min, then ultrasonically cleaned in ethanol for 5-10min, and then dried for later use. The pretreated TA10 alloy samples were then placed in an aluminate electrolyte system for micro-arc oxidation. The operating temperature was 40–60 °C, the micro-arc oxidation time was 5–20 min, and a constant voltage mode was used. The positive voltage was 300–480 V, the negative voltage was 30–50 V, the frequency was 400–650 Hz, and the positive and negative duty cycle pulse width ratio was 20–40%. Using this method, a film layer with a thickness of 95–110 μm and good density, corrosion resistance, and wear resistance can be prepared on the surface of TA10 alloy used in chemical reactors, effectively improving the working efficiency and safety of TA10 alloy in chemical reactor applications. Attached Figure Description

[0006] Figure 1 This is a SEM image of the surface of the 2#TA10 alloy coated sample prepared in Example 1 of the present invention. Detailed Implementation

[0007] The present invention will be further described below, but this is not intended to limit the invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the scope of protection of the present invention.

[0008] The method for preparing a wear-resistant and corrosion-resistant titanium alloy micro-arc oxidation film for chemical reactors according to the present invention includes substrate pretreatment, micro-arc oxidation, and cleaning and drying steps, specifically including: A. Substrate pretreatment: Polish, clean, and dry the surface of the titanium alloy substrate; B. Micro-arc oxidation: The pretreated titanium alloy substrate is placed in an electrolyte prepared from aluminate, and a wear-resistant and corrosion-resistant ceramic film is prepared by micro-arc oxidation. C. Cleaning and drying: Clean and dry the coated titanium alloy after micro-arc oxidation treatment.

[0009] In the substrate pretreatment process, the titanium alloy is TA10 alloy.

[0010] The polishing process involves sequentially grinding the surface of the titanium alloy substrate with metallographic sandpaper of 800 to 6000#, then polishing it with diamond polishing paste of 5 to 0.5 μm, and finally ultrasonically cleaning it with ethanol to remove the grinding debris from the surface of the titanium alloy substrate.

[0011] The cleaning process involves washing the polished titanium alloy substrate with 10-15 g / L NaOH for 6-8 minutes, followed by ultrasonic cleaning in ethanol for 5-10 minutes to remove oil and stains from the surface of the titanium alloy substrate.

[0012] In the micro-arc oxidation process, the titanium alloy substrate is immersed in an electrolytic cell containing an electrolyte prepared from aluminate for micro-arc oxidation treatment. The titanium alloy substrate is connected to an aluminum strip, which is connected to the positive electrode of the micro-arc oxidation power source. The diameter of the aluminum strip is 1 cm.

[0013] The electrolyte prepared from the aluminate contains 6-8 g / L NaAlO2, 1.0-2.0 g / L NaOH, 0.5-1.5 g / L NaCl, and 0.2-0.8 g / L citric acid, preferably 7 g / L NaAlO2, 1.5 g / L NaOH, 1 g / L NaCl, and 0.5 g / L citric acid. The aluminate is of analytical grade.

[0014] The process parameters for micro-arc oxidation are as follows: electrolyte operating temperature is 40~60℃, micro-arc oxidation time is 5~20min, constant voltage operation mode is selected, positive voltage is 300~480V, negative voltage is 30~50V, frequency is 400~650Hz, and positive and negative duty pulse width ratio is 20~40%.

[0015] In the cleaning and drying process, the cleaning refers to washing the coated titanium alloy after micro-arc oxidation treatment with deionized water.

[0016] The wear-resistant and corrosion-resistant ceramic film prepared by the method described in this invention has a thickness of 95~110μm, a hardness of 1200~1400HV, and an average coefficient of friction of 0.31~0.36.

[0017] Example 1 Titanium alloy sample preparation: TA10 alloy plates were cut into TA10 alloy test samples No. 1 and No. 2 with a length of 15 mm, a width of 15 mm, and a thickness of 15 mm using a wire cutting machine.

[0018] A. Substrate Pretreatment: The surfaces of TA10 alloy substrates #1 and #2 were coarsely ground with 800#, 1000#, 2000#, and 3000# metallographic sandpaper, respectively, followed by fine grinding with 4000#, 5000#, and 6000# metallographic sandpaper. Polishing was then performed with diamond polishing pastes of 5μm, 3.5μm, 2.5μm, 1.5μm, and 0.5μm. The substrates were then ultrasonically cleaned with ethanol to remove grinding debris. After polishing, the substrates were rinsed with 10g / L NaOH for 6 minutes, followed by ultrasonic cleaning in ethanol for 5 minutes to remove oil and stains. The substrates were then dried.

[0019] B. Micro-arc oxidation: The electrolyte was prepared using aluminates. The electrolyte contained 7 g / L NaAlO2, 1.5 g / L NaOH, 1 g / L NaCl and 0.5 g / L citric acid. All reagents used were of analytical grade.

[0020] The pretreated titanium alloy substrate was immersed in an electrolytic cell containing an electrolyte prepared from aluminate. The titanium alloy substrate was connected to an aluminum strip with a diameter of 1 cm, and the aluminum strip was connected to the positive electrode of a micro-arc oxidation power source. A wear-resistant and corrosion-resistant ceramic film was prepared using micro-arc oxidation treatment.

[0021] The micro-arc oxidation process parameters for TA10 alloy substrate #1 are set as follows: electrolyte operating temperature 40℃, micro-arc oxidation time 10min, constant voltage operation mode, positive voltage 350V, negative voltage 30V, frequency 450Hz, and positive and negative duty cycle 20%. The micro-arc oxidation process parameters for TA10 alloy substrate #2 are set as follows: electrolyte operating temperature 40℃, micro-arc oxidation time 15min, constant voltage operation mode, positive voltage 450V, negative voltage 30V, frequency 500Hz, and positive and negative duty cycle 30%.

[0022] C. Cleaning and drying: Clean the coated titanium alloy after micro-arc oxidation treatment with deionized water and then dry it.

[0023] The thickness of the wear-resistant and corrosion-resistant ceramic film was measured using a YUWESE film thickness gauge. The measurement results of the ceramic film thickness on the surface of TA10 alloy #1 and #2 are shown in Table 1.

[0024] Table 1. Measurement results of ceramic film thickness on the surface of TA10 alloys #1 and #2 The hardness of the wear-resistant and corrosion-resistant ceramic film was measured using a Vickers hardness tester. The measurement results of the ceramic film on the surface of TA10 alloy #1 and #2 are shown in Table 2.

[0025] Table 2. Measurement results of the hardness of the ceramic film layer on the surface of TA10 alloys #1 and #2. The corrosion resistance of TA10 alloy coated samples #1 and #2 was tested by immersing them in 100 g / L hydrochloric acid solution. The corrosion resistance was evaluated by the weight reduction of the samples. The results are shown in Table 3.

[0026] Table 3. Measurement results of corrosion resistance of TA10 alloy samples #1 and #2 Both TA10 alloy coated samples #1 and #2 can form relatively uniform and dense ceramic films with excellent wear and corrosion resistance on their surfaces. The SEM observation results of the surface of TA10 alloy coated sample #2 are as follows: Figure 1 As shown.

[0027] The wear-resistant and corrosion-resistant ceramic film prepared by the method described in this invention has a thickness of 95~110μm, a hardness of 1200~1400HV, and an average coefficient of friction of 0.31~0.36.

[0028] Example 2 Titanium alloy sample preparation: Same as in Example 1.

[0029] A. Substrate Pretreatment: The surfaces of TA10 alloy substrates #1 and #2 were coarsely ground with 800#, 1000#, 2000#, and 3000# metallographic sandpaper, respectively, followed by fine grinding with 4000#, 5000#, and 6000# metallographic sandpaper. Then, they were polished with diamond polishing paste of 5μm, 3.5μm, 2.5μm, 1.5μm, and 0.5μm. Afterward, the substrates were ultrasonically cleaned with ethanol to remove grinding debris. The polished substrates were then alkali-washed with 15g / L NaOH for 8 minutes, followed by ultrasonic cleaning in ethanol for 10 minutes to remove oil and stains before drying.

[0030] B. Micro-arc oxidation: Electrolyte was prepared using aluminate, and the composition of the electrolyte was the same as in Example 1.

[0031] The pretreated titanium alloy substrate was immersed in an electrolytic cell containing an electrolyte prepared from aluminate. The titanium alloy substrate was connected to an aluminum strip with a diameter of 1 cm, and the aluminum strip was connected to the positive electrode of a micro-arc oxidation power source. A wear-resistant and corrosion-resistant ceramic film was prepared using micro-arc oxidation treatment.

[0032] The micro-arc oxidation process parameters for TA10 alloy substrate #1 are set as follows: electrolyte operating temperature 60℃, micro-arc oxidation time 5min, constant voltage operation mode, positive voltage 480V, negative voltage 50V, frequency 400Hz, and positive and negative duty cycle 40%. The micro-arc oxidation process parameters for TA10 alloy substrate #2 are set as follows: electrolyte operating temperature 60℃, micro-arc oxidation time 20min, constant voltage operation mode, positive voltage 300V, negative voltage 50V, frequency 650Hz, and positive and negative duty cycle 20%.

[0033] C. Cleaning and drying: Clean the coated titanium alloy after micro-arc oxidation treatment with deionized water and then dry it.

Claims

1. A method for preparing a wear-resistant and corrosion-resistant titanium alloy micro-arc oxidation film for chemical reactors, characterized in that... The process includes substrate pretreatment, micro-arc oxidation, and cleaning and drying, specifically including: A. Substrate pretreatment: Polish, clean, and dry the surface of the titanium alloy substrate; B. Micro-arc oxidation: The pretreated titanium alloy substrate is placed in an electrolyte prepared from aluminate, and a wear-resistant and corrosion-resistant ceramic film is prepared by micro-arc oxidation. C. Cleaning and drying: Clean and dry the coated titanium alloy after micro-arc oxidation treatment; The electrolyte prepared from the aluminate contains 6~8 g / L NaAlO2, 1.0~2.0 g / L NaOH, 0.5~1.5 g / L NaCl, and 0.2~0.8 g / L citric acid. The process parameters for micro-arc oxidation are as follows: electrolyte operating temperature is 40~60℃, micro-arc oxidation time is 5~20min, constant voltage operation mode is selected, positive voltage is 300~480V, negative voltage is 30~50V, frequency is 400~650Hz, and positive and negative duty pulse width ratio is 20~40%. The ceramic film has a thickness of 95~110μm and a hardness of 1200~1400HV; The titanium alloy mentioned is TA10 alloy.

2. The preparation method according to claim 1, characterized in that... In the substrate pretreatment process, polishing refers to grinding the surface of the titanium alloy substrate with metallographic sandpaper of 800 to 6000# in sequence, polishing it with diamond polishing paste of 5 to 0.5μm, and then ultrasonically cleaning it with ethanol to remove the grinding debris from the surface of the titanium alloy substrate.

3. The preparation method according to claim 1, characterized in that... In the substrate pretreatment process, the cleaning refers to washing the polished titanium alloy substrate with 10-15 g / L NaOH alkali for 6-8 minutes, and then ultrasonically cleaning it in ethanol for 5-10 minutes to remove oil and stains from the surface of the titanium alloy substrate.

4. The preparation method according to claim 1, characterized in that... In the micro-arc oxidation process, the titanium alloy substrate is immersed in an electrolytic cell containing an electrolyte prepared from aluminate for micro-arc oxidation treatment. The titanium alloy substrate is connected to an aluminum strip, and the aluminum strip is connected to the positive electrode of the micro-arc oxidation power source.

5. The preparation method according to claim 4, characterized in that... In the micro-arc oxidation process, the diameter of the aluminum strip is 1 cm.

6. The preparation method according to claim 4, characterized in that... In the micro-arc oxidation process, the aluminate is of analytical grade.

7. The preparation method according to claim 1, characterized in that... In the cleaning and drying process, the cleaning refers to washing the coated titanium alloy after micro-arc oxidation treatment with deionized water.

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