A repair solution and method for oxide film on cast magnesium parts

Abstract

This invention pertains to a process for repairing localized damage to the oxide film on cast magnesium parts, specifically a repair solution and method for this oxide film. The repair solution comprises magnesium oxide and sodium dichromate, with magnesium oxide content at 40-50 g / L and sodium dichromate content at 4-6 g / L. Using this repair solution, the oxide film forms rapidly with a thickness of 5-8 μm; it withstands neutral salt spray for 96 hours; and it has a uniform purplish-black color. Suitable for localized repair of both small and large parts, the preparation and operation method is simple and low-cost, the repair time is short, and the pass rate is high. It can be widely applied to the repair of locally damaged oxide films on cast magnesium parts in military, aerospace, shipbuilding, and civilian applications, with good results and without the need for part disassembly.

Description

TECHNICAL FIELD

[0001] The application belongs to the process of local damage repair of cast magnesium part oxidation film, and relates to a cast magnesium part oxidation film repair liquid and a repair method. BACKGROUND

[0002] Currently, some cast magnesium part oxidation parts are found to be scratched and damaged on the outer surface when assembled into a motor, and need to be locally repaired. However, the current cast magnesium part oxidation film local damage repair liquid formula has complex components and is not convenient to adjust, and the film layer repair is slow. The traditional process formula of the cast magnesium part oxidation film repair liquid is prepared by 4-5 kinds of drugs, and the preparation is complicated, the film forming effect is not good, the repaired film is easy to oxidize and turn black, and the film layer is generated slowly. The traditional oxidation film thickness is generally 0.5-3um, and the corrosion resistance is poor. In order to improve the corrosion resistance, the oxidation film needs to be treated by filling heavy chromate or coating. The most important reason is that the traditional process formula of the cast magnesium part oxidation film repair liquid has many kinds of drugs, the dosage of the repair liquid is small, and the proportion is easy to be out of adjustment, which causes the poor repair effect of the repaired film. SUMMARY

[0003] The purpose of the application is to solve the problem of the process method of local damage repair of cast magnesium part oxidation film.

[0004] The technical scheme of the application is a cast magnesium part oxidation film repair liquid, and the components of the cast magnesium part oxidation film repair liquid include magnesium oxide and sodium dichromate, wherein the content of the magnesium oxide is 40-50g / L, and the content of the sodium dichromate is 4-6g / L.

[0005] The magnesium oxide and the sodium dichromate are reagent types.

[0006] The preparation method of the cast magnesium part oxidation film repair liquid is as follows: according to the components of the cast magnesium part oxidation film repair liquid, distilled water is heated to 40-50 DEG C, 70-80% magnesium oxide is added in proportion under stirring, 20-25% sodium dichromate is added after 30 seconds, the liquid is left to stand until the liquid temperature drops to 30 DEG C, the remaining proportion of magnesium oxide and sodium dichromate is added under stirring, and the liquid is left to stand until the liquid temperature drops to room temperature.

[0007] A cast magnesium part oxidation film repair method is as follows: the surface of the workpiece to be repaired is first scrubbed with 180 gasoline to remove oil stains, then the damaged place is gently wiped with a water-soaked degreasing cotton stick with a proper amount of detergent powder, then the polished place is cleaned with a degreasing cotton stick with anhydrous alcohol, the prepared repair liquid is evenly coated on the polished place for 20-30 seconds, then the repaired place is cleaned with a degreasing cotton stick with water, and the repaired place is dried with a hair dryer.

[0008] The temperature of the prepared repair liquid is 30-40 DEG C.

[0009] The temperature of the workpiece reaches 30-40 DEG C before the repair liquid is coated.

[0010] The cast magnesium part oxide film repairing method adopts immersion coating repair or spraying repair method.

[0011] After the cast magnesium part oxide film is repaired, the workpiece is subjected to aging treatment, is baked in an oven at 50-60 DEG C for 30-40 minutes, the corrosion resistance is increased, and discoloration is prevented.

[0012] The cast magnesium part oxide film repairing method has the advantages that the cast magnesium part oxide film repairing liquid film layer is generated fast, the film layer thickness can reach 5-8 microns, the salt spray resistance is 96 hours, the color is purple black, and the color is uniform. DETAILED DESCRIPTION

[0013] The application is further described below in combination with specific embodiments.

[0014] The cast magnesium part oxide film repairing liquid comprises magnesium oxide and sodium dichromate, wherein the content of the magnesium oxide is 40-50 grams per liter, and the content of the sodium dichromate is 4-6 grams per liter.

[0015] The preparation method of the cast magnesium part oxide film repairing liquid comprises the following steps: first, distilled water is heated to 40-50 DEG C, 70-80% magnesium oxide is added in proportion while stirring, 20-25% sodium dichromate is added after 30 seconds, the liquid is left to stand until the liquid temperature drops to 30 DEG C, and then the remaining proportion of the magnesium oxide and the remaining proportion of the sodium dichromate are added while stirring, and the liquid is left to stand until the liquid temperature drops to room temperature.

[0016] The cast magnesium part oxide film repairing method comprises the following steps: first, the surface of the workpiece to be repaired is cleaned with 180 gasoline or acetone, then the surface is cleaned with water-soaked degreasing cotton to which a proper amount of detergent is added, the damaged part is cleaned and polished with degreasing cotton to which anhydrous alcohol is added, the prepared repairing liquid is uniformly applied to the polished part for 20-30 seconds, then the repaired part is cleaned with degreasing cotton to which water is added, and the workpiece is dried with a hair dryer.

[0017] The cast magnesium part oxide film repairing method also adopts immersion coating repair or spraying repair method.

[0018] After the cast magnesium part oxide film is repaired, the workpiece is subjected to aging treatment, is baked in an oven at 50-60 DEG C for 30-40 minutes, the corrosion resistance is increased, and discoloration is prevented.

[0019] Example 1: Oxide film brush coating repair method for cast magnesium parts

[0020] First step formula:

[0021] Oxide film repair solution for cast magnesium parts

[0022]

[0023]

[0024] Second step preparation method: Take the preparation of 5 liters of oxide film repair solution for cast magnesium parts as an example. First, take 5 liters of distilled water in a beaker and heat it to 40°C. While stirring, add 140 grams of magnesium oxide. After 30 seconds, add 4 grams of sodium dichromate. Keep the solution at 30°C and while stirring, first add 60 grams of magnesium oxide, then add 16 grams of sodium dichromate. Stir for 30 seconds and let the solution cool to room temperature before use.

[0025] Third step operation: The new process method is to repair the local damage of the oxide film surface of the cast magnesium part. The method is to first clean the surface of the part to be repaired with 180 gasoline to remove surface oil, then use water-soaked degreasing cotton to stick a suitable amount of detergent and gently wipe the damaged area. Then use degreasing cotton to stick anhydrous alcohol to clean and polish the area. Apply the prepared repair solution evenly to the polished area for 20 seconds, then clean the repaired area with water-soaked degreasing cotton, and dry it with a hair dryer. After repairing the oxide film of the cast magnesium part, the workpiece is subjected to aging treatment in an oven at 50°C for 40 minutes to increase the corrosion resistance and prevent discoloration.

[0026] Fourth step: Preparation and use of oxide film repair solution for cast magnesium parts:

[0027] (1) When preparing, strictly follow the order of adding medicines and continuously stir the solution while adding medicines.

[0028] (2) The prepared solution can be stored for 2 months, and the used solution must not be returned to the storage container.

[0029] (3) When using the prepared solution, ensure the temperature and time.

[0030] Example 2: Oxide film spray repair method for cast magnesium parts

[0031] First step formula:

[0032] Oxide film repair solution for cast magnesium parts

[0033]

[0034] The second step of the preparation method is as follows: Taking the preparation of 5 liters of magnesium oxide film repair solution as an example, first take 5 liters of distilled water in a beaker, heat it to 40°C, add 140 grams of magnesium oxide while stirring, add 4 grams of sodium dichromate after 30 seconds, keep the solution at 30°C, add 60 grams of magnesium oxide while stirring, then add 16 grams of sodium dichromate, stir for 30 seconds, and let the solution cool to room temperature before use.

[0035] Step 3: The new process allows for localized repair of the oxide film on cast magnesium parts. The method involves first cleaning the area to be repaired with acetone to remove surface oil. Then, using a water-soaked cotton ball dipped in a suitable amount of scouring powder, gently wipe the damaged area. Next, clean the polished area with anhydrous alcohol using a cotton ball. Apply the prepared repair solution evenly to the polished area for 20 seconds, then clean the repaired area with water using a cotton ball, and finally dry it with a hairdryer. After repairing the oxide film, the workpiece undergoes an aging treatment by baking it in an oven at 50℃ for 40 minutes to increase corrosion resistance and prevent discoloration.

[0036] Step 4: Preparation and Usage Precautions for Re-oxidation Solution for Magnesium Castings:

[0037] (1) When preparing the solution, add the medicines in strict order and stir the solution continuously while adding the medicines.

[0038] (2) The prepared solution can be stored for 2 months. The used solution must not be poured back into the storage container.

[0039] (3) When using the prepared solution, ensure the temperature and time.

[0040] Example 3: Brush Coating Repair Method for Oxide Film on Cast Magnesium Parts

[0041] Step 1 Recipe:

[0042] Composition of oxide film repair solution for cast magnesium parts

[0043]

[0044] The second step of the preparation method is as follows: Taking the preparation of 5 liters of magnesium oxide film repair solution as an example, first take 5 liters of distilled water in a beaker, heat it to 40°C, add 250 grams of magnesium oxide while stirring, add 6 grams of sodium dichromate after 30 seconds, keep the solution at 30°C, add 50 grams of magnesium oxide while stirring, then add 24 grams of sodium dichromate, stir for 30 seconds, and let the solution cool to room temperature before use.

[0045] Step 3: The new process allows for localized repair of the oxide film on cast magnesium parts. The method involves first cleaning the area to be repaired with acetone to remove surface oil. Then, using a water-soaked cotton ball dipped in a suitable amount of scouring powder, gently wipe the damaged area. Next, clean the polished area with anhydrous alcohol using a cotton ball. Apply the prepared repair solution evenly to the polished area with a cotton swab for 30 seconds, then clean the repaired area with water using a cotton ball and dry it with a hairdryer. After repairing the oxide film, the workpiece undergoes an aging treatment by baking it in an oven at 50℃ for 40 minutes to increase corrosion resistance and prevent discoloration.

[0046] Step 4: Preparation and Usage Precautions for Re-oxidation Solution for Magnesium Castings:

[0047] (1) When preparing the solution, add the medicines in strict order and stir the solution continuously while adding the medicines.

[0048] (2) The prepared solution can be stored for 2 months. The used solution must not be poured back into the storage container.

[0049] (3) When using the prepared solution, ensure the temperature and time.

[0050] Example 4: Spray Repair Method for Oxide Film on Cast Magnesium Parts

[0051] Step 1 Recipe:

[0052] Composition of oxide film repair solution for cast magnesium parts

[0053]

[0054] The second step of the preparation method is as follows: Taking the preparation of 5 liters of magnesium oxide film repair solution as an example, first take 5 liters of distilled water in a beaker, heat it to 40°C, add 250 grams of magnesium oxide while stirring, add 6 grams of sodium dichromate after 30 seconds, keep the solution at 30°C, add 50 grams of magnesium oxide while stirring, then add 24 grams of sodium dichromate, stir for 30 seconds, and let the solution cool to room temperature before use.

[0055] Step 3: The new process allows for localized repair of the oxide film on cast magnesium parts. The method involves first cleaning the area to be repaired with 180-octane gasoline to remove surface oil. Then, using a water-soaked cotton ball dipped in a suitable amount of scouring powder, gently wipe the damaged area. Next, clean the polished area with anhydrous alcohol using a cotton ball. Apply the prepared repair solution evenly to the polished area for 30 seconds, then clean the repaired area with water using a cotton ball, and finally dry it with a hairdryer. After repairing the oxide film, the workpiece undergoes an aging treatment by baking it in an oven at 50°C for 40 minutes to increase corrosion resistance and prevent discoloration.

[0056] Step 4: Preparation and Usage Precautions for Re-oxidation Solution for Magnesium Castings:

[0057] (1) When preparing the solution, add the medicines in strict order and stir the solution continuously while adding the medicines.

[0058] (2) The prepared solution can be stored for 2 months. The used solution must not be poured back into the storage container.

[0059] (3) When using the prepared solution, ensure the temperature and time.

Claims

1. A magnesium cast member oxidation film repairing solution, characterized by comprising: a magnesium cast member oxidation film repairing agent; and a solvent. The composition of the magnesium casting part oxide film repairing liquid comprises magnesium oxide and sodium dichromate, wherein the content of the magnesium oxide is 40-50 g / L, and the content of the sodium dichromate is 4-6 g / L; according to the composition of the magnesium casting part oxide film repairing liquid, distilled water is heated to 40-50 ℃, 70-80% magnesium oxide is added in proportion while stirring, 20-25% sodium dichromate is added after 30 seconds, and the remaining proportion of magnesium oxide and sodium dichromate is added while stirring when the liquid temperature drops to 30 ℃, and the stirring is performed for another 30 seconds, and the liquid is left to stand until the liquid temperature drops to room temperature, and then the magnesium casting part oxide film repairing liquid can be used.

2. The magnesium cast member oxidation film repairing solution according to claim 1, characterized by, The magnesium oxide and the sodium dichromate are reagents.

3. A method of repairing an oxidation film of a cast magnesium member, characterized by, The repairing liquid as claimed in claim 1 or 2 is used to clean the surface of the workpiece to be repaired by using No. 180 gasoline, then the workpiece is cleaned by using degreasing cotton to stick a proper amount of detergent and gently wiping the damaged part, then the workpiece is cleaned by using degreasing cotton to stick anhydrous alcohol, the prepared repairing liquid is evenly applied to the cleaned part for 20-30 seconds, then the workpiece is cleaned by using degreasing cotton to stick water, and the workpiece is dried by using a hair dryer.

4. The cast magnesium member oxidation film repairing method according to claim 3, characterized by, The temperature of the prepared repairing liquid is 30-40 ℃.

5. The cast magnesium member oxidation film repairing method according to claim 3, characterized by, The temperature of the workpiece before the repairing liquid is applied is 30-40 ℃.

6. The cast magnesium member oxidation film repairing method according to claim 3, characterized by, The magnesium casting part oxide film repairing method is a dipping or spraying repairing method.

7. The cast magnesium member oxidation film repairing method according to claim 3, characterized by, After the magnesium casting part oxide film is repaired, the workpiece is subjected to aging treatment, and is baked in an oven at 50-60 ℃ for 30-40 minutes.

Images