A method for preparing Hureaulite manganese phosphate conversion film

Abstract

The invention discloses a method for preparing a Hureaulite manganese phosphate conversion film, comprising the following specific steps: step 1: preparing raw materials, preparing solid powdered raw materials A by using Marif salt and sodium hydroxide powder; step 2: pre-treating the substrate, grinding and degreasing the substrate; step 3: coating raw materials, preparing solid powdered raw materials A into a paste mixture, and coating the paste mixture on the substrate; step 4: synthesizing the Hureaulite phosphate conversion film. The present invention is (1) simpler and has lower cost when used, directly using water-assisted solid phase crystallization reaction to prepare the conversion film, avoiding the process of preparing complex phosphating liquid, and not needing to purchase a variety of additives to prepare liquid, only two chemical raw materials, Marif salt and sodium hydroxide, are needed; (2) more environmentally friendly, no complex waste liquid is generated, and no solid phosphating residue is generated; (3) the conversion rate is higher; (4) easy to operate and safe and reliable.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of Hureaulite manganese phosphate conversion film, in particular to a preparation method of Hureaulite manganese phosphate conversion film. Background Art

[0002] Hureaulite manganese phosphate conversion film is commonly known as manganese phosphating film, which is mainly used in the field of surface protection of alloys (magnesium alloys, aluminum alloys, steel, etc.). The current preparation process is to immerse the alloy in a pre-prepared acidic solution (containing heavy metals and other types of toxic additives) at a certain temperature for a certain period of time. The significant disadvantages of this process are: (1) a large amount of waste liquid containing chemicals such as phosphorus and heavy metals is generated; (2) a large amount of solid residue is generated during the reaction, affecting product quality; (3) because the process involves multiple steps of solution chemical reactions, the reaction balance makes the final conversion rate often not high. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing Hureaulite manganese phosphate conversion film to solve the problems raised in the above background technology: (1) a large amount of waste liquid containing chemicals such as phosphorus and heavy metals is generated; (2) a large amount of solid residue is generated during the reaction, affecting the product quality; and (3) since the process involves multiple steps of solution chemical reactions, the reaction equilibrium often makes the final conversion rate low.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for preparing a Hureaulite manganese phosphate conversion film, comprising the following specific steps:

[0005] Step 1: Prepare the raw materials, weigh 10-20 grams of Marib salt, add water and stir until dissolved, then add 2-4 grams of sodium hydroxide powder, continue stirring for 5-30 minutes, filter the solution, and then dry the filtered solution to obtain a solid powdered raw material A with a grain size of 1-20 microns;

[0006] Step 2: Pre-treatment of the substrate, select the metal parts that need to be coated, and then use 400# sandpaper to polish them. After completion, use 800# sandpaper to polish them, then use 1500# sandpaper to polish them, and finally use 2000# sandpaper to polish them until they are bright. At this time, the polishing work is completed to ensure that the outer surface of the metal parts is in a smooth state. After that, the polished metal parts are degreased for standby use;

[0007] Step 3: coating the raw material, mixing the solid powdered raw material A obtained in step 1 with the solvent to make the solid powdered raw material A into a paste mixture, and then evenly coating the paste mixture on the outer surface of the pretreated metal part to complete the coating work;

[0008] Step 4: Synthesize Hureaulite phosphate conversion film, heat the substrate obtained in step 3 with 70-160°C water or steam, and perform crystal transformation for 10-100 minutes until a dense Hureaulite manganese phosphate conversion film is obtained on the surface of the metal part, thus completing the coating work.

[0009] Preferably, the raw materials used in step 1 are all common raw materials.

[0010] Preferably, the dissolved water used in step 1 is deionized water to prevent impurities in the water source from affecting the quality of subsequent products.

[0011] Preferably, the solution obtained in step 1 is filtered through a 100-120 mesh filter.

[0012] Preferably, in step 2, 400# sandpaper is used for polishing, and then 800# sandpaper is used for polishing, followed by 1500# sandpaper, and finally 2000# sandpaper is used for polishing until it is bright, and cleaning is required after each polishing.

[0013] Preferably, in step 3, the paste mixture adheres to the surface of the metal part and cannot flow, which is the best state.

[0014] Preferably, after the coating is completed in step 4, the finished product is rinsed, and then dried to remove residual raw materials on the surface.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] Compared with the existing methods, the preparation method described in the present invention has the following advantages: (1) It is simpler and has lower cost. It directly uses water-assisted solid-phase crystallization reaction to prepare the conversion film, avoiding the process of preparing complex phosphating solutions. It is not necessary to purchase a variety of additives to prepare the solutions. Only two chemical raw materials, Marib salt and sodium hydroxide, are required; (2) It is more environmentally friendly. It does not produce complex waste liquid or solid phosphating residue; (3) The conversion rate is higher; (4) It is easy to operate and safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the present invention. Implementation

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0019] See also Figure 1 The present invention provides a technical solution: a method for preparing a Hureaulite manganese phosphate conversion film, comprising the following specific steps:

[0020] Step 1: Prepare the raw materials, weigh 12 grams of Marib salt, add water and stir until dissolved, then add 2 grams of sodium hydroxide powder, continue stirring for 15 minutes, then filter the solution through a 100-mesh filter, and then dry the filtered solution to obtain a solid powdered raw material A;

[0021] Step 2: Pretreatment of the substrate, select the aluminum alloy that needs to be coated, and then use 400# sandpaper to polish it. After polishing, clean the outer surface of the aluminum alloy. After polishing, use 800# sandpaper to polish it. After polishing, clean it once. Then use 1500# sandpaper to polish it. After polishing, clean the outer surface of the aluminum alloy. Finally, use 2000# sandpaper to polish it to a bright state, and then clean it. At this time, the polishing work is completed, ensuring that the outer surface of the aluminum alloy is in a smooth state. Then, the polished aluminum alloy is degreased for standby use;

[0022] Step 3: coating raw materials, mixing the solid powdered raw material A obtained in step 1 with a solvent, so that the solid powdered raw material A is made into a paste mixture, which is attached to the surface of the aluminum alloy and cannot flow, which is the best state, and then the paste mixture is evenly coated on the outer surface of the pretreated aluminum alloy to complete the coating work;

[0023] Step 4: Synthesize Hureaulite phosphate conversion film, soak and heat the substrate obtained in step 3 with 90°C water, and perform crystal transformation for 50 minutes until a dense Hureaulite manganese phosphate conversion film is obtained on the surface of the aluminum alloy. After completion, rinse the finished product, dry it after rinsing, and remove the residual raw materials on the surface, thus completing the coating work. Example

[0024] See also Figure 1 The present invention provides a technical solution: a method for preparing a Hureaulite manganese phosphate conversion film, comprising the following specific steps:

[0025] Step 1: Prepare the raw materials, weigh 20 grams of Marif salt, add 500 milliliters of water and stir until dissolved, then add 3 grams of sodium hydroxide powder, continue stirring for 10 minutes, then filter the solution through a 120-mesh filter, and then dry the filtered solution to obtain a solid powdered raw material A;

[0026] Step 2: Matrix pretreatment, select the magnesium alloy sheet that needs to be coated, the AZ30 magnesium alloy sheet with the specification of 40 mm × 20 mm × 1 mm, and then use 400# sandpaper for grinding. After grinding, clean the outer surface of the magnesium alloy. After completion, use 800# sandpaper for grinding. After grinding, clean it once. Then use 1500# sandpaper for grinding. After grinding, clean the outer surface of the magnesium alloy. Finally, use 2000# sandpaper to grind to a bright state, and then clean it. At this time, the grinding work is completed, ensuring that the outer surface of the magnesium alloy is in a smooth state. Place it in anhydrous ethanol for ultrasonic degreasing for five minutes, take it out and blow dry it for standby use;

[0027] Step 3: coating raw materials, mixing 2 grams of solid powdered raw material A obtained in step 1 with ethanol solvent, so that the solid powdered raw material A is made into a paste mixture, which is attached to the surface of the magnesium alloy and cannot flow, which is the best state, and then the paste mixture is evenly coated on the outer surface of the pretreated magnesium alloy to complete the coating work;

[0028] Step 4: Synthesize Hureaulite phosphate conversion film, soak and heat the magnesium alloy obtained in step 3 with 80°C water for 10 minutes, until a dense Hureaulite manganese phosphate conversion film is obtained on the surface of the magnesium alloy, rinse the finished product after completion, and dry it after rinsing to remove the residual raw materials on the surface, thus completing the coating work. Example

[0029] See also Figure 1 The present invention provides a technical solution: a method for preparing a Hureaulite manganese phosphate conversion film, comprising the following specific steps:

[0030] Step 1: Prepare the raw materials, weigh 16 grams of Marib salt, add 200 milliliters of water and stir until dissolved, then add 3 grams of sodium hydroxide powder, continue stirring for 10 minutes, then filter the solution through a 100-mesh filter, and then dry the filtered solution to obtain a solid powdered raw material A;

[0031] Step 2: Pretreatment of the substrate, select the pure copper sheet that needs to be plated, the specification is 20 mm × 20 mm × 1 mm pure copper sheet, and then use 400# sandpaper for polishing. After polishing, clean the outer surface of the pure copper sheet, and then use 800# sandpaper for polishing. After polishing, clean it once, and then use 1500# sandpaper for polishing. After polishing, clean the outer surface of the pure copper sheet, and finally use 2000# sandpaper to polish to a bright state, and then clean it. At this time, the polishing work is completed, ensuring that the outer surface of the pure copper sheet is in a smooth state. Then, place the polished pure copper sheet in anhydrous ethanol for ultrasonic degreasing for 5 minutes, take it out and blow dry;

[0032] Step 3: coating raw materials, mixing 4 grams of solid powdered raw material A obtained in step 1 with a water solvent, so that the solid powdered raw material A is made into a paste mixture, which is attached to the surface of the pure copper sheet and cannot flow, which is the best state, and then the paste mixture is evenly coated on the outer surface of the pretreated pure copper sheet to complete the coating work;

[0033] Step 4: Synthesize Hureaulite phosphate conversion film, heat the pure copper sheet obtained in step 3 with 180°C steam, and perform crystal transformation for 100 minutes until a dense Hureaulite manganese phosphate conversion film is obtained on the surface of the pure copper sheet. After completion, rinse the finished product, dry it after rinsing, and remove the residual raw materials on the surface, thus completing the coating work.

[0034] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0035] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a Hureaulite manganese phosphate conversion film, characterized in that: The specific steps include: Step 1: Prepare the raw materials, weigh 10-20 grams of Marib salt, add water and stir until dissolved, then add 2-4 grams of sodium hydroxide powder, continue stirring for 5-30 minutes, filter the solution, and then dry the filtered solution to obtain a solid powdered raw material A with a grain size of 1-20 microns; Step 2: Pre-treatment of the substrate, select the metal parts that need to be coated, and then use 400# sandpaper to polish them. After completion, use 800# sandpaper to polish them, then use 1500# sandpaper to polish them, and finally use 2000# sandpaper to polish them until they are bright. At this time, the polishing work is completed to ensure that the outer surface of the metal parts is in a smooth state. After that, the polished metal parts are degreased for standby use; Step 3: coating the raw material, mixing the solid powdered raw material A obtained in step 1 with the solvent to make the solid powdered raw material A into a paste mixture, and then evenly coating the paste mixture on the outer surface of the pretreated metal part to complete the coating work; Step 4: Synthesize Hureaulite phosphate conversion film, heat the substrate obtained in step 3 with 70-160°C water or steam, and perform crystal transformation for 10-100 minutes until a dense Hureaulite manganese phosphate conversion film is obtained on the surface of the metal part, thus completing the coating work.

2. The method for preparing a Hureaulite manganese phosphate conversion film according to claim 1, characterized in that: The dissolved water used in step 1 is deionized water to prevent impurities in the water source from affecting the quality of subsequent products.

3. The method for preparing a Hureaulite manganese phosphate conversion film according to claim 1, characterized in that: The solution obtained in step 1 is filtered through a 100-120 mesh filter.

4. The method for preparing a Hureaulite manganese phosphate conversion film according to claim 1, characterized in that: In step 2, use 400# sandpaper for sanding, then use 800# sandpaper for sanding, then use 1500# sandpaper for sanding, and finally use 2000# sandpaper to sand until it is bright. The surface needs to be cleaned after each sanding.

5. The method for preparing a Hureaulite manganese phosphate conversion film according to claim 1, characterized in that: In step 3, the coating degree is such that the paste-like mixture adheres to the surface of the metal part and cannot flow.

6. The method for preparing a Hureaulite manganese phosphate conversion film according to claim 1, characterized in that: After the coating is completed in step 4, the finished product is rinsed, dried after rinsing, and the residual raw materials on the surface are removed.

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