Magnesium alloy surface sealant, method of making and use thereof

Abstract

The application belongs to the technical field of magnesium alloy surface treatment, and particularly relates to a magnesium alloy surface sealing agent, a preparation method and application thereof. The magnesium alloy surface sealing agent comprises the following components with mass concentrations: 90g / L-110g / L water-based resin, 13g / L-25g / L polyethylene glycol dithioacetate, 0.23g / L-1.36g / L 4-mercapto-benzenesulfonic acid, 1g / L-1.5g / L polyvinyl alcohol, 0.5g / L-1g / L nano boron nitride, 0.2g / L-0.5g / L tannic acid, 0.1g / L-0.2g / L perfluorodecyltrimethoxysilane and 70g / L-80g / L isopropyl alcohol. The magnesium alloy surface sealing agent provided by the application is an environmentally-friendly sealing agent with super-high corrosion resistance and high adhesion.

Description

Technical Field

[0001] This invention belongs to the field of magnesium alloy surface treatment technology, specifically relating to a magnesium alloy surface sealant, its preparation method, and its application. Background Technology

[0002] Traditional magnesium alloy surface sealants mainly include chromate sealants and nickel salt sealants. Chromate sealants are highly toxic, as chromium is a carcinogenic heavy metal that can seriously harm human health and the ecological environment. Nickel salt sealants can cause water pollution, which in turn harms the environment and the health of animals and plants.

[0003] To address this, environmentally friendly silicate sealants and oil-impregnated sealants have been proposed. However, existing silicate sealants suffer from incomplete sealing (residual pores), damage to the film layer (such as micro-arc oxidation films), and poor corrosion resistance; while oil-impregnated sealants provide physical sealing, but the film layer cannot fill the pores and has low slow-release efficiency. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a magnesium alloy surface sealant, its preparation method, and its application, thereby resolving at least one aspect of the technical issues described above.

[0005] This invention is achieved through the following technical solution: In a first aspect, the present invention provides a magnesium alloy surface sealant comprising the following components by mass concentration: 90g / L~110g / L waterborne resin, 13g / L~25g / L polyethylene glycol dithioacetate, 0.23g / L~1.36g / L 4-mercaptophenylboronic acid, 1g / L~1.5g / L polyvinyl alcohol, 0.5g / L~1g / L nano boron nitride, 0.2g / L~0.5g / L tannic acid, 0.1g / L~0.2g / L perfluorodecyltrimethoxysilane, 70g / L~80g / L isopropanol.

[0006] In some possible implementations, the waterborne resin includes at least one of waterborne silicone resin and waterborne phenolic resin.

[0007] In some possible implementations, the polyethylene glycol dithioacetate has a relative molecular weight of 2000 to 4000.

[0008] In some possible implementations, the relative molecular weight of the polyvinyl alcohol is 15,000 to 20,000.

[0009] In some possible implementations, the particle size D50 of the boron nanoparticles is 50 nm to 100 nm.

[0010] Secondly, the present invention provides a method for preparing the above-mentioned magnesium alloy surface sealant, comprising the following steps: According to the preset ratio, nano boron nitride and perfluorodecyltrimethoxysilane are ultrasonically mixed, then stirred and mixed with water-based resin, polyethylene glycol dithioacetate, 4-mercaptophenylboronic acid, polyvinyl alcohol, tannic acid and isopropanol, and then further stirred with water.

[0011] In some possible implementations, the ultrasonic mixing time is 20 min to 40 min.

[0012] In some possible implementations, the temperature of the ultrasonic mixing is 40°C to 60°C.

[0013] In some possible implementations, the ultrasonic power of the ultrasonic mixture is 200W to 400W.

[0014] In some possible implementations, the stirring speed for mixing is 400 rpm to 800 rpm.

[0015] In some possible implementations, the mixing time is 1 hour to 3 hours.

[0016] In some possible implementations, the mixing temperature is 50°C to 60°C.

[0017] In some possible implementations, the continued stirring process includes the following steps: Add water to the preset concentration and adjust the pH to 8-8.5, then continue stirring.

[0018] In some possible implementations, the stirring speed is 300 rpm to 600 rpm.

[0019] In some possible implementations, the pH value is adjusted using a sodium hydroxide solution.

[0020] In some possible implementations, the concentration of the sodium hydroxide solution is 0.2 mol / L to 0.3 mol / L.

[0021] In some possible implementations, the continued stirring time is 5h to 9h.

[0022] Thirdly, the present invention provides an application of the above-mentioned magnesium alloy surface sealant in the field of alloy surface protection.

[0023] The magnesium alloy surface sealant provided by this invention has at least the following beneficial technical effects compared with the prior art: The magnesium alloy surface sealant provided by this invention is an environmentally friendly sealant with ultra-high corrosion resistance and high adhesion.

[0024] The method for preparing the magnesium alloy surface sealant provided by this invention has at least the following beneficial technical effects compared with the prior art: The method for preparing a magnesium alloy surface sealant provided by this invention involves first mixing nano-boron nitride and perfluorodecyltrimethoxysilane, then modifying the nano-boron nitride with perfluorodecyltrimethoxysilane, and finally mixing it with an aqueous resin, polyethylene glycol dithioacetate, 4-mercaptophenylboronic acid, polyvinyl alcohol, tannic acid, and isopropanol. The mixture is then further stirred with water to obtain a magnesium alloy surface sealant that is an environmentally friendly sealant with ultra-high corrosion resistance and high adhesion. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0026] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0027] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0028] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0029] This invention provides a magnesium alloy surface sealant, comprising the following components by mass concentration: 90g / L~110g / L waterborne resin, 13g / L~25g / L polyethylene glycol dithioacetate, 0.23g / L~1.36g / L 4-mercaptophenylboronic acid, 1g / L~1.5g / L polyvinyl alcohol, 0.5g / L~1g / L nano boron nitride, 0.2g / L~0.5g / L tannic acid, 0.1g / L~0.2g / L perfluorodecyltrimethoxysilane, 70g / L~80g / L isopropanol.

[0030] The magnesium alloy surface sealant provided in this invention utilizes polyethylene glycol dithioacetate (SAc-PEG-SAc), polyvinyl alcohol, mercaptophenylboronic acid, nano-boron nitride, and tannic acid to synergistically significantly improve the sealant's adhesion. Furthermore, the hydrolysis of perfluorodecyltrimethoxysilane provides superhydrophobic properties, effectively blocking water molecules. Isopropanol promotes the dissolution and dispersion of silane and organic matter. The magnesium alloy surface sealant provided in this invention is an environmentally friendly sealant with ultra-high corrosion resistance and high adhesion.

[0031] In some specific embodiments, the aqueous silicone resin includes at least one of KRW-6000 and KRW-6002.

[0032] In some specific embodiments, the aqueous phenolic resin includes MQ-8022.

[0033] In some embodiments, the relative molecular weight of polyethylene glycol dithioacetate is 2000-4000.

[0034] In some specific embodiments, polyethylene glycol dithioacetate is SAc-PEG2k-SAc (molecular weight 2k) produced by Xi'an Qiyue Biotechnology.

[0035] In some embodiments, the CAS number of 4-mercaptophenylboronic acid is 237429-33-3.

[0036] In some embodiments, the relative molecular weight of polyvinyl alcohol is 15,000 to 20,000.

[0037] In some embodiments, the particle size D50 of the boron nitride nanoparticles is 50 nm to 100 nm.

[0038] In some embodiments, the CAS number of tannic acid is 72401-53-7.

[0039] In some embodiments, the CAS number of perfluorodecyltrimethoxysilane (1H,1H,2H,2H-heptadecyltrimethoxysilane) is 83048-65-1.

[0040] A second aspect of this invention provides a method for preparing a magnesium alloy surface sealant, comprising the following steps: S10. According to the preset ratio, nano boron nitride and perfluorodecyltrimethoxysilane are ultrasonically mixed, and then stirred and mixed with water-based resin, polyethylene glycol dithioacetate, 4-mercaptophenylboronic acid, polyvinyl alcohol, tannic acid and isopropanol, and then stirred and treated with water.

[0041] The method for preparing a magnesium alloy surface sealant provided in this invention involves first mixing nano-boron nitride and perfluorodecyltrimethoxysilane, then modifying the nano-boron nitride with perfluorodecyltrimethoxysilane, and finally mixing it with an aqueous resin, polyethylene glycol dithioacetate, 4-mercaptophenylboronic acid, polyvinyl alcohol, tannic acid, and isopropanol. The mixture is then further stirred with water to obtain a magnesium alloy surface sealant that is an environmentally friendly sealant with ultra-high corrosion resistance and high adhesion.

[0042] In some embodiments, the ultrasonic mixing time in step S10 is 20 min to 40 min. In this case, boron nitride nanoparticles can be uniformly dispersed in perfluorodecyltrimethoxysilane without damaging the nanostructure of boron nitride nanoparticles.

[0043] In some embodiments, in step S10 above, the temperature of ultrasonic mixing is 40°C to 60°C.

[0044] In some embodiments, in step S10 above, the ultrasonic power of the ultrasonic mixing is 200W~400W.

[0045] In some embodiments, in step S10 above, the stirring speed for mixing is 400 rpm to 800 rpm.

[0046] In some embodiments, the mixing time in step S10 is 1h to 3h.

[0047] In some embodiments, in step S10 above, the temperature for stirring and mixing is 50°C to 60°C.

[0048] In some embodiments, the continued stirring process in step S10 above includes the following steps: S101. Add water according to the preset concentration and adjust the pH value to 8~8.5, then continue stirring.

[0049] In some embodiments, in step S101 above, the stirring speed is 300 rpm to 600 rpm.

[0050] In some embodiments, in step S101 above, the pH value is adjusted to 8-8.5 using sodium hydroxide solution.

[0051] In some embodiments, the concentration of the sodium hydroxide solution is 0.2 mol / L to 0.3 mol / L.

[0052] In some embodiments, in step S101 above, the stirring time is 5h to 9h.

[0053] The following description, in conjunction with specific embodiments, provides further details.

[0054] Example 1 Example 1 provides a magnesium alloy surface sealant, composed of the following components at the following mass concentrations: 100g / L waterborne silicone resin KRW-6000, 20g / L polyethylene glycol dithioacetate (SAc-PEG-SAc), 1g / L 4-mercaptophenylboronic acid, 1.3g / L polyvinyl alcohol, 0.8g / L nano boron nitride, 0.4g / L tannic acid, 0.2g / L perfluorodecyltrimethoxysilane, 78.5g / L isopropanol.

[0055] Among them, polyethylene glycol dithioacetate is SAc-PEG2k-SAc (molecular weight of 2k) produced by Xi'an Qiyue Biotechnology.

[0056] The relative molecular weight of polyvinyl alcohol is 20,000.

[0057] The particle size D50 of the boron nitride nanoparticles is 80 nm.

[0058] The CAS number for perfluorodecyltrimethoxysilane is 83048-65-1.

[0059] This embodiment also provides a method for preparing the above-mentioned magnesium alloy surface sealant, the steps of which are as follows: E10. Ultrasonic Mixing Nano-boron nitride and perfluorodecyltrimethoxysilane are ultrasonically mixed according to a preset ratio to obtain a mixture.

[0060] The ultrasonic power was 300W, the ultrasonic temperature was 50℃, and the ultrasonic time was 30min.

[0061] E20. Stir and mix. Under stirring at 600 rpm, KRW-6000, polyethylene glycol dithioacetate, 4-mercaptophenylboronic acid, polyvinyl alcohol, tannic acid and isopropanol were added to the mixture in sequence to obtain a mixed system.

[0062] The mixing temperature was 60℃ and the time was 2 hours.

[0063] E30. Continue stirring. While stirring at 400 rpm, add water according to the preset concentration and adjust the pH value to 8~8.5 with sodium hydroxide solution (0.25mol / L), then continue stirring.

[0064] The stirring was continued at a temperature of 60℃ for 7 hours.

[0065] Example 2 Example 2 provides a magnesium alloy surface sealant, composed of the following components at the following mass concentrations: 110 g / L waterborne silicone resin KRW-6002, 13 g / L polyethylene glycol dithioacetate (SAc-PEG-SAc), 0.23 g / L 4-mercaptophenylboronic acid, 1 g / L polyvinyl alcohol, 0.5 g / L nano boron nitride, 0.2 g / L tannic acid, 0.1 g / L perfluorodecyltrimethoxysilane, 70 g / L isopropanol.

[0066] Among them, polyethylene glycol dithioacetate is SAc-PEG2k-SAc (molecular weight of 2k) produced by Xi'an Qiyue Biotechnology.

[0067] The relative molecular weight of polyvinyl alcohol is 20,000.

[0068] The particle size D50 of the boron nitride nanoparticles is 80 nm.

[0069] The CAS number for perfluorodecyltrimethoxysilane is 83048-65-1.

[0070] This embodiment also provides a method for preparing the above-mentioned magnesium alloy surface sealant, with the same steps as in Example 1.

[0071] Example 3 Example 3 provides a magnesium alloy surface sealant, composed of the following components at the following mass concentrations: 90 g / L waterborne phenolic resin MQ-8022, 25 g / L polyethylene glycol dithioacetate (SAc-PEG-SAc), 1.36 g / L 4-mercaptophenylboronic acid, 1.5 g / L polyvinyl alcohol, 1 g / L nano boron nitride, 0.5 g / L tannic acid, 0.2 g / L perfluorodecyltrimethoxysilane, 80 g / L isopropanol.

[0072] The relative molecular weight of polyethylene glycol dithioacetate is 3000.

[0073] The relative molecular weight of polyvinyl alcohol is 20,000.

[0074] The particle size D50 of the boron nitride nanoparticles is 80 nm.

[0075] The CAS number for perfluorodecyltrimethoxysilane is 83048-65-1.

[0076] This embodiment also provides a method for preparing the above-mentioned magnesium alloy surface sealant, with the same steps as in Example 1.

[0077] Comparative Example 1 Comparative Example 1 provides a magnesium alloy surface sealant, composed of the following components at the following mass concentrations: 100g / L waterborne silicone resin KRW-6000, 20g / L polyethylene glycol, 1.3g / L polyvinyl alcohol, 0.8g / L nano boron nitride, 0.4g / L tannic acid, 0.2g / L perfluorodecyltrimethoxysilane, 78.5g / L isopropanol.

[0078] The polyethylene glycol used is PEG 2000.

[0079] The relative molecular weight of polyvinyl alcohol is 20,000.

[0080] The particle size D50 of the boron nitride nanoparticles is 80 nm.

[0081] The CAS number for perfluorodecyltrimethoxysilane is 83048-65-1.

[0082] This comparative example also provides a method for preparing a magnesium alloy surface sealant, the steps of which are as follows: D10. According to the preset ratio, nano boron nitride and perfluorodecyltrimethoxysilane are ultrasonically mixed, then mixed with polyethylene glycol, polyvinyl alcohol, tannic acid and isopropanol, and then water is added to obtain a magnesium alloy surface sealant.

[0083] Comparative Example 2 Comparative Example 2 provides a magnesium alloy surface sealant, composed of the following components at the following mass concentrations: 100g / L waterborne silicone resin KRW-6000, 20g / L polyethylene glycol, 1.3g / L polyvinyl alcohol, 0.8g / L nano boron nitride, 0.4g / L tannic acid, 78.5g / L isopropanol.

[0084] The polyethylene glycol is PEG 2000.

[0085] The relative molecular weight of polyvinyl alcohol is 20,000.

[0086] The particle size D50 of the boron nitride nanoparticles is 80 nm.

[0087] This comparative example also provides a method for preparing a magnesium alloy surface sealant, the steps of which are as follows: D11. According to the preset ratio, KRW-6000, nano boron nitride, polyethylene glycol, polyvinyl alcohol, tannic acid and isopropanol are stirred and mixed, and then water is added to obtain a magnesium alloy surface sealant.

[0088] To verify the advancement of the magnesium alloy surface sealant and its preparation method provided in this embodiment of the invention, the magnesium alloy surface sealants prepared in this embodiment and the comparative example were used to form a sealing film on the magnesium alloy surface, and their corrosion resistance and adhesion were tested. The results are shown in Table 1 below.

[0089] in: (1) The preparation steps of the sealing film are as follows: Pretreatment: After the magnesium alloy parts have undergone phosphate conversion coating treatment, they should be thoroughly washed with water and kept moist but without water accumulation.

[0090] Sealing treatment: Immerse the workpiece in a sealing agent at a temperature of 50°C for 15 minutes while gently stirring.

[0091] Film formation: After removing the workpiece, bake it at 80°C for 15 minutes to remove moisture, and then bake it at 120°C for 45 minutes.

[0092] (2) Corrosion resistance conditions: 35℃±1℃, 5%±0.5%NaCl salt spray, 800h.

[0093] (3) Adhesion test: cross-cut test.

[0094] Table 1

[0095] From Table 1 above, at least the following conclusions can be drawn: In Comparative Example 1, polyethylene glycol was used, and the adhesion of the resulting sealing film remained unchanged, but significant corrosion was observed. In Comparative Example 2, unmodified polyethylene glycol was used without the addition of perfluorodecyltrimethoxysilane, and significant pitting corrosion was observed, with a significant reduction in adhesion. Therefore, the magnesium alloy surface sealant provided in this embodiment of the invention utilizes polyethylene glycol dithioacetate and 4-mercaptophenylboronic acid, which, in synergy with water-based resin, polyvinyl alcohol, perfluorodecyltrimethoxysilane, and nano-boron nitride, significantly improve the adhesion of the sealant.

[0096] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A magnesium alloy surface sealant, characterized in that, Components including the following mass concentrations: 90g / L~110g / L waterborne resin, 13g / L~25g / L polyethylene glycol dithioacetate, 0.23g / L~1.36g / L 4-mercaptophenylboronic acid, 1g / L~1.5g / L polyvinyl alcohol, 0.5g / L~1g / L nano boron nitride, 0.2g / L~0.5g / L tannic acid, 0.1g / L~0.2g / L perfluorodecyltrimethoxysilane, 70g / L~80g / L isopropanol.

2. The magnesium alloy surface sealant according to claim 1, characterized in that, It satisfies at least one of the following characteristics (1) to (4): (1) The waterborne resin includes at least one of waterborne organosilicon resin and waterborne phenolic resin; (2) The relative molecular weight of the polyethylene glycol dithioacetate is 2000~4000; (3) The relative molecular weight of the polyvinyl alcohol is 15,000 to 20,000; (4) The particle size D50 of the nano boron nitride is 50nm~100nm.

3. A method for preparing a magnesium alloy surface sealant as described in claim 1 or 2, characterized in that, Includes the following steps: According to the preset ratio, nano boron nitride and perfluorodecyltrimethoxysilane are ultrasonically mixed, then stirred and mixed with water-based resin, polyethylene glycol dithioacetate, 4-mercaptophenylboronic acid, polyvinyl alcohol, tannic acid and isopropanol, and then further stirred with water.

4. The method for preparing the magnesium alloy surface sealant according to claim 3, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The ultrasonic mixing time is 20 min to 40 min; (2) The temperature of the ultrasonic mixing is 40℃~60℃; (3) The ultrasonic power of the ultrasonic mixture is 200W~400W.

5. The method for preparing the magnesium alloy surface sealant according to claim 4, characterized in that, It satisfies at least one of the following characteristics (1) to (3): (1) The stirring speed for the mixing process is 400 rpm to 800 rpm; (2) The mixing time is 1h to 3h; (3) The mixing temperature is 50℃~60℃.

6. The method for preparing the magnesium alloy surface sealant according to any one of claims 3 to 5, characterized in that, The continued stirring process includes the following steps: Add water to the preset concentration and adjust the pH to 8-8.5, then continue stirring.

7. The method for preparing the magnesium alloy surface sealant according to claim 6, characterized in that, The stirring speed is 300 rpm to 600 rpm.

8. The method for preparing the magnesium alloy surface sealant according to claim 6 or 7, characterized in that, The pH value was adjusted using sodium hydroxide solution.

9. The method for preparing the magnesium alloy surface sealant according to claim 8, characterized in that, It satisfies at least one of the following characteristics (1) to (2): (1) The concentration of the sodium hydroxide solution is 0.2 mol / L to 0.3 mol / L; (2) The stirring time is 5h~9h.

10. The application of a magnesium alloy surface sealant as described in claim 1 or 2 in the field of alloy surface protection.

Images