阅读说明：本技术 一种粉状脱模剂喷涂前的压铸模型腔的处理工艺 (Treatment process of die-casting mold cavity before spraying of powdery release agent ) 是由 黎宏 倪明主 黎思瑶 于 2020-11-09 设计创作，主要内容包括：本发明公开了一种粉状脱模剂喷涂前的压铸模型腔的处理工艺,涉及压力铸造技术领域,具体工艺包括如下步骤：S1压铸模型腔预处理,S2压铸模型腔处理剂的制备,以及S3压铸模型腔的加工处理。本发明中,通过在压铸模型腔的表面形成一层由硅藻土复合物构成的沉积层,硅藻土复合物中填充有聚乙烯蜡,粉状脱模剂在喷涂时,熔融态的脱模剂会渗入到沉积层中,并与沉积层中的液态聚乙烯蜡发生互渗,从而在沉积层与薄膜的界面处,形成由脱模剂与聚乙烯蜡形成的互渗层,形成的互渗层可以很好的提高薄膜与沉积层之间的结合强度,提高了脱模剂薄膜的粘结力,从而有助于提高脱模剂的周转使用次数,实现粉状脱模剂的使用寿命的提升。(The invention discloses a treatment process of a die-casting mold cavity before spraying a powdery release agent, which relates to the technical field of pressure casting, and specifically comprises the following steps: the method comprises the steps of S1 die-casting die cavity pretreatment, S2 die-casting die cavity treating agent preparation and S3 die-casting die cavity processing treatment. According to the invention, the deposited layer composed of the diatomite composite is formed on the surface of the die-casting die cavity, the polyethylene wax is filled in the diatomite composite, and when the powdery release agent is sprayed, the molten release agent can permeate into the deposited layer and mutually permeate with the liquid polyethylene wax in the deposited layer, so that the mutually permeated layer formed by the release agent and the polyethylene wax is formed at the interface of the deposited layer and the film, and the formed mutually permeated layer can well improve the bonding strength between the film and the deposited layer, improve the bonding force of the release agent film, thereby being beneficial to improving the turnover use times of the release agent and realizing the improvement of the service life of the powdery release agent.)

1. A treatment process of a die-casting mold cavity before spraying of a powdery release agent is characterized by comprising the following specific processes:

s1 die casting mould cavity pretreatment

1) Removing impurities in a die-casting mold cavity by adopting a blowing mode, immersing the die-casting mold cavity into a sodium salt mixed solution, carrying out heat treatment for 15-20min at 70-80 ℃, taking out the die-casting mold cavity, washing the die-casting mold cavity by using distilled water, measuring a proper amount of concentrated sulfuric acid, diluting the concentrated sulfuric acid by using the distilled water until the mass concentration is 4-6%, carrying out acid washing for 10-15s, and repeatedly washing the die-casting mold cavity by using the distilled water for later use;

2) weighing an appropriate amount of deionized water to wet the nano titanium dioxide, adding an appropriate amount of sodium dodecyl sulfate, uniformly mixing, performing ultrasonic dispersion for 10-15min, adding the obtained nano titanium dioxide suspension into the plating solution, continuing to perform ultrasonic dispersion for 30-40min to obtain a composite plating solution, fixedly placing a spare die-casting model as a cathode and a nickel plate with equal area as an anode into the composite plating solution, adjusting the temperature of the plating solution to 50-60 ℃, and adjusting the current density to 2-3A/dm²Electroplating for 20-30min, taking out the die-casting mold after the treatment is finished, repeatedly washing with distilled water, and drying;

preparation of S2 die casting cavity treating agent

1) Weighing a proper amount of magnesium chloride and boric acid, adding the magnesium chloride and boric acid into deionized water, stirring until the magnesium chloride and boric acid are completely dissolved to obtain a transparent mixed solution, slowly dropwise adding a proper amount of ammonia water, pouring a precipitate formed in the solution into an autoclave container lined with polytetrafluoroethylene, sealing, putting the autoclave container into an oven, reacting for 8-10h at the temperature of 180 ℃, cooling to room temperature after the reaction is finished, repeatedly washing the obtained precipitate with deionized water, drying, putting the autoclave container into a tubular furnace, heating to the temperature of 700-;

2) adding diatomite and magnesium borate nanowires into deionized water, mechanically stirring for 1-2h, performing ultrasonic treatment for 40-50min, uniformly mixing, performing suction filtration on the mixture, drying, placing the mixture into a container, weighing a proper amount of polyethylene wax, adding the polyethylene wax into the container, adding a proper amount of paraffin oil, placing the container into an oven with the temperature of 135 ℃ plus material of 145 ℃, vacuumizing to 30-60Pa, keeping the vacuum state for 60-80min after the polyethylene wax is completely dissolved, vacuumizing again to 20-50Pa after pressure relief, continuing vacuum treatment for 1-2h, taking out the product, placing the product into the oven, and repeatedly drying at the temperature of 150 ℃ plus material of 160 ℃ until no polyethylene wax is separated out to obtain a diatomite composite;

3) adding the diatomite composite into a container, heating the container to 120 ℃ in an oil bath, adding mercaptopropyltrimethoxysilane diluted by ethanol under continuous stirring, stirring the mixture at a constant temperature for 30-40min, adding a proper amount of hydrogen peroxide/glacial acetic acid mixed solution after the stirring is finished, reacting the mixture for 2-3h at the temperature of 50-55 ℃, filtering and drying a product, and dispersing the product in distilled water to obtain a required treating agent;

processing treatment of die-casting die cavity of S3

Immersing the pretreated die casting model into a treating agent, adjusting the pH value to 2-3, heating in water bath to 70-75 ℃, stirring at constant temperature for 4-5h, standing for 12-15h, taking out the treated die casting model, repeatedly washing with distilled water, and drying to complete the required treatment process.

2. The process for treating a die-casting die cavity before spraying of the powdery release agent as claimed in claim 1, wherein in the process step S1.1), the sodium salt mixed solution is composed of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate in a mass ratio of 1:1:1:1, and distilled water in a mass ratio of 1: 6-8.

3. The process for treating the die-casting die cavity before spraying the powdery release agent as claimed in claim 1, wherein in the process step S1.2), the power of the ultrasonic dispersion is 150-200W; the pH value of the composite plating solution is 4-5, and the composite plating solution contains 230-260g/L of nickel sulfate, 35-45g/L of nickel chloride, 30-40g/L of boric acid, 2-3g/L of nano titanium dioxide and 0.5-1.5g/L of sodium dodecyl sulfate.

4. The process for treating a die-casting mold cavity before spraying of a powdery mold release agent as claimed in claim 1, wherein in the process step S2.1), the molar ratio of the magnesium chloride to the boric acid is 1: 1.4-1.6; in the transparent mixed solution, the concentration of magnesium chloride is 0.02-0.04 mol/L; the mass concentration of the ammonia water is 25-28%, and the dropping amount is 13-17% of the volume of the transparent mixed solution; the heating rate in the tubular furnace is 2-3 ℃/min.

5. The process for treating a die-casting die cavity before spraying of the powdery release agent as claimed in claim 1, wherein in the process step S2.2), the mass-to-volume ratio of the diatomite to the deionized water is 1:80-100 g/mL; the addition amount of the magnesium borate nanowire is 3-6% of the mass of the diatomite; the using amount of the polyethylene wax is 35-50% of the mass of the diatomite; the dosage of the paraffin oil is 3-4 times of the mass of the polyethylene wax.

6. The process for treating a die-casting mold cavity before spraying of the powdery mold release agent as claimed in claim 1, wherein in the process step S2.2), the rotation speed of the mechanical stirring is 600-800 r/min; the ultrasonic power is 300-400W.

7. The process for treating a die-casting die cavity before spraying of the powdery release agent as claimed in claim 1, wherein in the process step S2.3), the mass concentration of the ethanol is 60-80%, and the mass ratio of the ethanol to the mercaptopropyl trimethoxysilane is 1-1.5: 1; the mass-volume ratio of the diatomite composite to the mercaptopropyltrimethoxysilane diluted by ethanol is 1:20-30 g/mL; the hydrogen peroxide/glacial acetic acid mixed solution consists of 20-30% of hydrogen peroxide and glacial acetic acid according to the volume ratio of 2-3:1, and the addition amount of the hydrogen peroxide/glacial acetic acid mixed solution is 10-13% of the total volume of the reaction system.

8. The process for treating a die-casting mold cavity before spraying of a powdery mold release agent according to claim 1, wherein in the process step S2.3), the stirring rotation speed is 80 to 100 r/min; the solid content of the treating agent is 5-8%.

Technical Field

The invention belongs to the technical field of pressure casting, and particularly relates to a treatment process of a die-casting mold cavity before spraying of a powdery release agent.

Background

The release agent is an indispensable auxiliary material in die-casting production, has the main function of enabling a casting to be taken out of a die cavity of the die, can form a layer of film after being sprayed on the high-temperature surface of the die, protects the surface of the die cavity, prevents the casting from sticking the die, reduces the impact effect of molten metal on the die cavity when the casting is formed by injection, reduces the abrasion of the casting and the die cavity, and plays a role in lubrication; in addition, the temperature of each part of the die can be adjusted, the effect of keeping the temperature of the die balanced is achieved, the formability of the casting is improved, the service life of the die is prolonged, the quality of the die casting is guaranteed to a certain extent, and the service life of the die is prolonged.

At present, the widely used release agents are mainly water-based release agents and powder release agents, wherein the deinking effect of the water-based release agents depends on a film with the thickness of only micron-sized deposited on the surface of a cavity after spraying, so that the component sorting and the using process have higher requirements, and the water-based release agents are excessively mixed with water, so that a thick film is formed when the spraying amount is excessive, and the film of the release agents forms slow solution accumulation, generates gas, forms wrinkles, deposits and the like on the surface of a die casting piece, and has certain influence on the quality of the casting piece. Based on this, the powder release agent is increased by more than 10% every year, and is one of the coating varieties with wide development and application prospects. The powdery release agent is a release agent variety which takes air as a carrier for dispersion and coating, has extremely high production efficiency, excellent film coating performance, good ecological environmental protection and outstanding economy, and can be easily separated, smooth and clean when being sprayed on the surface of an object to be solidified into a film. The existing powdery release agent has good release effect and long service life, and at present, in order to further prolong the service life of the powdery release agent and reduce the use cost of the powdery release agent, the powdery release agent is mostly improved in the prior art, but the effect is very little, and the method is not ideal. The invention aims to realize the improvement of the service life of the powdery release agent by processing the die-casting die cavity.

Disclosure of Invention

The invention aims to provide a treatment process of a die-casting die cavity before spraying a powdery release agent, aiming at the existing problems.

The invention is realized by the following technical scheme:

a treatment process of a die-casting mold cavity before spraying of a powdery release agent comprises the following specific processes:

s1 die casting mould cavity pretreatment

1) Removing impurities in a die-casting mold cavity by adopting a blowing mode, immersing the die-casting mold cavity into a sodium salt mixed solution which is composed of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate with the mass ratio of 1:1:1:1 and distilled water according to the mass ratio of 1:6-8, carrying out heat treatment for 15-20min at 70-80 ℃, taking out the die-casting mold cavity, washing the die-casting mold cavity with distilled water, measuring a proper amount of concentrated sulfuric acid, diluting the die-casting mold cavity with the distilled water until the mass concentration is 4-6%, pickling for 10-15s, and repeatedly washing the die-casting mold cavity with the distilled water for later use; in the invention, the die cavity of the die casting mould is subjected to purging, oil washing and acid washing treatment, so that impurities in the die cavity can be removed, the cleanliness of the inner surface of the die cavity is improved, and the firmness of a subsequent die cavity surface coating is improved;

2) weighing a proper amount of deionized water to wet the nano titanium dioxide, adding a proper amount of sodium dodecyl sulfate, uniformly mixing, performing ultrasonic dispersion with 200W for 10-15min, adding the obtained nano titanium dioxide suspension into the plating solution, continuing the ultrasonic dispersion for 30-40min to obtain a composite plating solution, wherein the pH value of the obtained composite plating solution is 4-5, the composite plating solution contains 260g/L of nickel sulfate 230-plus, 35-45g/L of nickel chloride, 30-40g/L of boric acid, 2-3g/L of nano titanium dioxide and 0.5-1.5g/L of sodium dodecyl sulfate, a spare die-casting model is used as a cathode, a nickel plate with equal area is used as an anode, the die-casting model is fixedly placed into the composite plating solution, the temperature of the plating solution is adjusted to 50-60 ℃, and the current density is 2-3A/dm²Electroplating for 20-30min, taking out the die-casting mold after the treatment is finished, repeatedly washing with distilled water, and drying; in the invention, a nickel-nano titanium dioxide composite electroplated layer is formed on the surface of the die-casting die cavity by adopting an electroplating process, and nano titanium dioxide particles in the composite electroplated layer can absorb the surface of the die-casting die cavity under an acidic conditionHydrogen ions are attached to the nano titanium dioxide to generate protonation, so that the nano titanium dioxide has positive charges, and can generate electrostatic self-assembly effect with a diatomite compound in a subsequent treating agent;

preparation of S2 die casting cavity treating agent

1) Adding weighed magnesium chloride and boric acid into deionized water according to the molar ratio of the magnesium chloride to the boric acid of 1:1.4-1.6, stirring until the magnesium chloride and the boric acid are completely dissolved to obtain a transparent mixed solution with the concentration of the magnesium chloride of 0.02-0.04mol/L, slowly dropwise adding ammonia water with the mass concentration of 25-28% according to 13-17% of the volume of the transparent mixed solution, pouring a precipitate formed in the solution into an autoclave container lined with polytetrafluoroethylene, sealing, placing the autoclave container into a drying oven, reacting at the temperature of 180 ℃ for 8-10h at 150 ℃., cooling to room temperature after the reaction is finished, repeatedly washing the obtained precipitate with deionized water, drying, placing the autoclave container into a tubular furnace, heating to the temperature of 700-;

2) adding diatomite (with the particle size of 20-30 microns) and magnesium borate nanowires accounting for 3-6% of the mass of the diatomite into deionized water according to the mass-volume ratio of the diatomite to the deionized water of 1:80-100g/mL, mechanically stirring for 1-2h at 800r/min with 600-400W ultrasonic treatment for 40-50min, uniformly mixing, carrying out suction filtration on the mixture, drying, placing in a container, weighing polyethylene wax accounting for 35-50% of the mass of the diatomite, adding into the container, adding paraffin oil accounting for 3-4 times of the mass of the polyethylene wax, placing the container in a 135-type 145 ℃ drying oven, vacuumizing to 30-60Pa, keeping the vacuum state for 60-80min after the polyethylene wax is completely dissolved, vacuumizing again to 20-50Pa after pressure relief, continuing vacuum treatment for 1-2h, then taking out the product, putting the product into an oven, and repeatedly drying the product at the temperature of 150-160 ℃ until no polyethylene wax is separated out to obtain the diatomite composite; according to the invention, diatomite is used as a carrier, vacuum pumping treatment is carried out at high temperature, polyethylene wax is dissolved in paraffin oil after being melted at high temperature, and the polyethylene wax permeates into a porous structure of the diatomite under the vacuum pumping action, and the added magnesium borate nanowires enter pores of the diatomite to form a net structure through mutual overlapping, so that the polyethylene wax can be limited from seeping out of the pores of the diatomite during melting;

3) adding the diatomite composite into a container, heating the mixture in an oil bath to 125 ℃, adding mercaptopropyltrimethoxysilane diluted by ethanol with the mass concentration of 60-80% into the container under the condition of continuously stirring the mixture at 80-100r/min, wherein the mass ratio of the ethanol to the mercaptopropyltrimethoxysilane is 1-1.5:1, continuously stirring the mixture at a constant temperature for 30-40min, adding a hydrogen peroxide/glacial acetic acid mixed solution consisting of 20-30% of hydrogen peroxide and glacial acetic acid in a volume ratio of 2-3:1 according to 10-13% of the total volume of a reaction system after stirring, reacting the mixture at 50-55 ℃ for 2-3h, filtering and drying a product, and dispersing the product into distilled water to obtain a treating agent with the solid content of 5-8%; according to the invention, mercaptopropyl trimethoxy silane is adopted to treat the diatomite composite, and an oxidant is adopted to carry out oxidation treatment, the oxidant can oxidize mercapto groups of a silane coupling agent into sulfonic acid groups which are easy to ionize, the diatomite composite with the sulfonic acid groups has negative charges in a solution, and can be spontaneously combined with nano titanium dioxide with positive charges in a composite electroplated layer under the action of electrostatic attraction, so that a deposition layer formed by the diatomite composite is formed on the surface of the composite electroplated layer;

processing treatment of die-casting die cavity of S3

Immersing the pretreated die casting model into a treating agent, adjusting the pH value to 2-3, heating in water bath to 70-75 ℃, stirring at constant temperature for 4-5h, standing for 12-15h, taking out the treated die casting model, repeatedly washing with distilled water, and drying to complete the required treatment process.

Compared with the prior art, the invention has the following advantages:

in the invention, a deposition layer composed of a diatomite composite is formed on the surface of a die-casting die cavity, polyethylene wax is filled in the diatomite composite, when the powdery release agent is sprayed, the polyethylene wax in the diatomite composite is melted into liquid under high-temperature environment, the sprayed powdery release agent is adhered to the deposition layer in a molten state, the molten release agent can permeate into the deposition layer and mutually permeate with the liquid polyethylene wax in the deposition layer, the release agent on the surface of the deposition layer can be solidified into a film along with the solidification of the molten release agent, the release agent permeating into the deposition layer is solidified into a convex thorn structure, and the polyethylene wax can be gradually solidified into a solid along with the reduction of temperature, the convex thorn structure in the deposition layer is embedded into the polyethylene wax to play a role in fixation, so that the mutually permeating layer formed by the release agent and the polyethylene wax is formed at the interface of the deposition layer and the film, the formed mutual-permeation layer can well improve the bonding strength between the film and the deposition layer, and the bonding force of the release agent film is improved, so that the turnover use times of the release agent are improved, and the service life of the powdery release agent is prolonged.

Detailed Description

The present invention will be further described with reference to specific embodiments.

Example 1

A treatment process of a die-casting mold cavity before spraying of a powdery release agent comprises the following specific processes:

s1 die casting mould cavity pretreatment

1) Removing impurities in a die-casting mold cavity by adopting a blowing mode, immersing the die-casting mold cavity into a sodium salt mixed solution which is composed of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate with the mass ratio of 1:1:1:1 and distilled water according to the mass ratio of 1:6, carrying out heat treatment for 15min at 70 ℃, taking out the die-casting mold cavity, washing the die-casting mold cavity with distilled water, measuring a proper amount of concentrated sulfuric acid, diluting the concentrated sulfuric acid with the distilled water until the mass concentration is 4%, carrying out acid washing for 10s, and repeatedly washing the die-casting mold cavity with the distilled water for later use;

2) weighing an appropriate amount of deionized water to wet the nano titanium dioxide, adding an appropriate amount of sodium dodecyl sulfate, uniformly mixing, performing ultrasonic dispersion for 10min at 150W, adding the obtained nano titanium dioxide suspension into a plating solution, continuing the ultrasonic dispersion for 30min to obtain a composite plating solution, wherein in the obtained composite plating solution, the pH value is 4, the composite plating solution contains 230g/L of nickel sulfate, 35g/L of nickel chloride, 30g/L of boric acid, 2g/L of nano titanium dioxide and 0.5g/L of sodium dodecyl sulfate, a spare die-casting model is used as a cathode, a nickel plate with equal area is used as an anode, the nickel plate is fixedly placed into the composite plating solution, the temperature of the plating solution is adjusted to 50 ℃, and the current density is 2A/²Electroplating for 20min, taking out the die casting mold after the treatment, and adding distilled waterRepeatedly washing and drying;

preparation of S2 die casting cavity treating agent

1) According to the molar ratio of magnesium chloride to boric acid being 1:1.4, weighing magnesium chloride and boric acid, adding into deionized water, stirring until the magnesium chloride and boric acid are completely dissolved to obtain a transparent mixed solution with the concentration of 0.02mol/L, slowly dropwise adding ammonia water with the mass concentration of 25% according to 13% of the volume of the transparent mixed solution, pouring a precipitate formed in the solution into an autoclave container lined with polytetrafluoroethylene, sealing, placing into a drying oven, reacting for 8 hours at 150 ℃, cooling to room temperature after the reaction is finished, repeatedly washing the obtained precipitate with deionized water, drying, placing into a tubular furnace, heating to 700 ℃ at the heating rate of 2 ℃/min, carrying out heat treatment for 3 hours, and cooling to room temperature along with the furnace to obtain magnesium borate nanowires;

2) adding diatomite (with the particle size of 20-30 microns) and magnesium borate nanowires accounting for 3% of the mass of the diatomite into deionized water according to the mass-to-volume ratio of the diatomite to the deionized water of 1:80g/mL, mechanically stirring for 1h at 600r/min, performing ultrasonic treatment for 40min at 300W, uniformly mixing, performing suction filtration on the mixture, drying, placing the mixture into a container, weighing polyethylene wax accounting for 35% of the mass of the diatomite, adding the polyethylene wax into the container, adding paraffin oil accounting for 3 times of the mass of the polyethylene wax, placing the container into a 135 ℃ oven, vacuumizing to 30Pa, keeping the vacuum state for 60min after the polyethylene wax is completely dissolved, decompressing, performing vacuum treatment again to 20Pa, continuing to perform vacuum treatment for 1h, taking out the product, placing the product into the oven, and repeatedly drying at 150 ℃ until no polyethylene wax is separated out to obtain a diatomite composite;

3) adding the diatomite composite into a container, heating the container to 120 ℃ in an oil bath, continuously stirring the container at 80r/min, adding mercaptopropyltrimethoxysilane diluted by ethanol with the mass concentration of 60%, wherein the mass ratio of the ethanol to the mercaptopropyltrimethoxysilane is 1:1, continuously stirring the mixture at a constant temperature for 30min, after the stirring is finished, adding a hydrogen peroxide/glacial acetic acid mixed solution consisting of 20% of hydrogen peroxide and glacial acetic acid in a volume ratio of 2:1 according to 10% of the total volume of a reaction system, reacting the mixture at 50 ℃ for 2h, filtering and drying a product, and dispersing the product in distilled water to obtain a treating agent with the solid content of 5%;

processing treatment of die-casting die cavity of S3

And (3) immersing the pretreated die casting mold into a treating agent, adjusting the pH value to 2, heating in a water bath to 70 ℃, stirring at a constant temperature for 4 hours, standing for 12 hours, taking out the treated die casting mold, repeatedly washing with distilled water, and drying to finish the required treatment process.

Example 2

A treatment process of a die-casting mold cavity before spraying of a powdery release agent comprises the following specific processes:

s1 die casting mould cavity pretreatment

1) Removing impurities in a die-casting mold cavity by adopting a blowing mode, immersing the die-casting mold cavity into a sodium salt mixed solution which is composed of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate with the mass ratio of 1:1:1:1 and distilled water according to the mass ratio of 1:7, carrying out heat treatment for 18min at 75 ℃, taking out the die-casting mold cavity, washing the die-casting mold cavity with distilled water, measuring an appropriate amount of concentrated sulfuric acid, diluting the die-casting mold cavity with the distilled water until the mass concentration is 5%, carrying out acid washing for 12s, and repeatedly washing the die-casting mold cavity with the distilled water for;

2) weighing a proper amount of deionized water to wet the nano titanium dioxide, adding a proper amount of sodium dodecyl sulfate, uniformly mixing, performing ultrasonic dispersion at 200W for 12min, adding the obtained nano titanium dioxide suspension into a plating solution, continuing to perform ultrasonic dispersion for 35min to obtain a composite plating solution, wherein the pH value of the obtained composite plating solution is 4.5, the composite plating solution contains 240g/L of nickel sulfate, 40g/L of nickel chloride, 35g/L of boric acid, 3g/L of nano titanium dioxide and 1.0g/L of sodium dodecyl sulfate, taking a spare die-casting model as a cathode, taking a nickel plate with equal area as an anode, fixedly placing the nickel plate into the composite plating solution, adjusting the temperature of the plating solution to 55 ℃, and adjusting the current density to 3A/dm²Electroplating for 25min, taking out the die casting mold after the treatment is finished, repeatedly washing with distilled water, and drying;

preparation of S2 die casting cavity treating agent

1) Weighing magnesium chloride and boric acid according to a molar ratio of the magnesium chloride to the boric acid of 1:1.5, adding the weighed magnesium chloride and boric acid into deionized water, stirring until the magnesium chloride and the boric acid are completely dissolved to obtain a transparent mixed solution with the concentration of 0.03mol/L, slowly dropwise adding ammonia water with the mass concentration of 27% according to 15% of the volume of the transparent mixed solution, pouring a precipitate formed in the solution into an autoclave container lined with polytetrafluoroethylene, sealing, putting the autoclave container into a drying oven, reacting for 9 hours at 160 ℃, cooling to room temperature after the reaction is finished, repeatedly washing the obtained precipitate with deionized water, drying, putting the washed precipitate into a tubular furnace, heating to 710 ℃ at the heating rate of 3 ℃/min, carrying out heat treatment for 3.5 hours, and cooling to the room temperature along with the furnace to obtain magnesium borate nanowires;

2) adding diatomite (with the particle size of 20-30 microns) and magnesium borate nanowires accounting for 5% of the mass of the diatomite into deionized water according to the mass-to-volume ratio of the diatomite to the deionized water of 1:90g/mL, mechanically stirring for 1.5h at 700r/min, performing 350W ultrasonic treatment for 45min, uniformly mixing, performing suction filtration on the mixture, drying, placing the mixture into a container, weighing polyethylene wax accounting for 45% of the mass of the diatomite, adding the polyethylene wax into the container, adding paraffin oil accounting for 3.5 times of the mass of the polyethylene wax, placing the container into an oven at 140 ℃, vacuumizing to 50Pa, keeping the vacuum state for 70min after the polyethylene wax is completely dissolved, releasing pressure, vacuumizing again to 30Pa, continuing to perform vacuum treatment for 1.5h, taking out a product, placing the product into the oven, and repeatedly drying at 155 ℃ until the polyethylene wax is not separated out to obtain a diatomite composite;

3) adding the diatomite composite into a container, heating the container to 123 ℃ in an oil bath, adding mercaptopropyltrimethoxysilane diluted by ethanol with the mass concentration of 70% under the condition of continuous stirring at 90r/min, wherein the mass ratio of the ethanol to the mercaptopropyltrimethoxysilane is 1.3:1, continuously stirring for 35min at a constant temperature, adding a hydrogen peroxide/glacial acetic acid mixed solution consisting of 25% by mass of hydrogen peroxide and 2.5:1 by volume of glacial acetic acid according to 12% of the total volume of a reaction system after stirring is finished, reacting for 2.5h at 52 ℃, filtering and drying a product, and dispersing the product in distilled water to obtain a treating agent with the solid content of 7%;

processing treatment of die-casting die cavity of S3

And (3) immersing the pretreated die casting model into a treating agent, adjusting the pH value to 2.5, heating in a water bath to 72 ℃, stirring at a constant temperature for 4.5 hours, standing for 13 hours, taking out the treated die casting model, repeatedly washing with distilled water, and drying to complete the required treatment process.

Example 3

A treatment process of a die-casting mold cavity before spraying of a powdery release agent comprises the following specific processes:

s1 die casting mould cavity pretreatment

1) Removing impurities in a die-casting mold cavity by adopting a blowing mode, immersing the die-casting mold cavity into a sodium salt mixed solution which is composed of sodium hydroxide, sodium carbonate, sodium phosphate and sodium silicate with the mass ratio of 1:1:1:1 and distilled water according to the mass ratio of 1:8, carrying out heat treatment for 20min at 80 ℃, taking out the die-casting mold cavity, washing the die-casting mold cavity with distilled water, measuring an appropriate amount of concentrated sulfuric acid, diluting the die-casting mold cavity with the distilled water until the mass concentration is 6%, carrying out acid washing for 15s, and repeatedly washing the die-casting mold cavity with the distilled water for;

2) weighing an appropriate amount of deionized water to wet the nano titanium dioxide, adding an appropriate amount of sodium dodecyl sulfate, uniformly mixing, performing ultrasonic dispersion for 15min at 200W, adding the obtained nano titanium dioxide suspension into a plating solution, continuing to perform ultrasonic dispersion for 40min to obtain a composite plating solution, wherein in the obtained composite plating solution, the pH value is 5, the composite plating solution contains 260g/L of nickel sulfate, 45g/L of nickel chloride, 40g/L of boric acid, 3g/L of nano titanium dioxide and 1.5g/L of sodium dodecyl sulfate, a spare die-casting model is used as a cathode, a nickel plate with equal area is used as an anode, the nickel plate is fixedly placed into the composite plating solution, the temperature of the plating solution is adjusted to be 60 ℃, and the current density is 3²Electroplating for 30min, taking out the die casting mold after the treatment is finished, repeatedly washing with distilled water, and drying;

preparation of S2 die casting cavity treating agent

1) According to the molar ratio of magnesium chloride to boric acid being 1:1.6, weighing magnesium chloride and boric acid, adding into deionized water, stirring until the magnesium chloride and boric acid are completely dissolved to obtain a transparent mixed solution with the concentration of 0.04mol/L, slowly dropwise adding ammonia water with the mass concentration of 28% according to 17% of the volume of the transparent mixed solution, pouring a precipitate formed in the solution into an autoclave container lined with polytetrafluoroethylene, sealing, putting into a drying oven, reacting for 10 hours at 180 ℃, cooling to room temperature after the reaction is finished, repeatedly washing the obtained precipitate with deionized water, drying, putting into a tubular furnace, heating to 720 ℃ at the heating rate of 3 ℃/min, carrying out heat treatment for 4 hours, and cooling to room temperature along with the furnace to obtain magnesium borate nanowires;

2) adding diatomite (with the particle size of 20-30 microns) and magnesium borate nanowires accounting for 6% of the mass of the diatomite into deionized water according to the mass-to-volume ratio of the diatomite to the deionized water of 1:100g/mL, mechanically stirring for 2h at 800r/min, performing 400W ultrasonic treatment for 50min, uniformly mixing, performing suction filtration on the mixture, drying, placing the mixture into a container, weighing polyethylene wax accounting for 50% of the mass of the diatomite, adding the polyethylene wax into the container, adding paraffin oil accounting for 4 times of the mass of the polyethylene wax, placing the container into a 145 ℃ oven, vacuumizing to 60Pa, keeping the vacuum state for 80min after the polyethylene wax is completely dissolved, decompressing, performing vacuum treatment again to 50Pa, continuing to perform vacuum treatment for 2h, taking out the product, placing the product into the oven, and repeatedly drying at 160 ℃ until no polyethylene wax is separated out to obtain a diatomite composite;

3) adding the diatomite composite into a container, heating the container to 125 ℃ in an oil bath, adding mercaptopropyltrimethoxysilane diluted by ethanol with the mass concentration of 80% under the condition of continuous stirring at 100r/min, wherein the mass ratio of the ethanol to the mercaptopropyltrimethoxysilane is 1.5:1, continuously stirring for 40min at a constant temperature, adding a hydrogen peroxide/glacial acetic acid mixed solution consisting of 30% of hydrogen peroxide and glacial acetic acid in a volume ratio of 3:1 according to 13% of the total volume of a reaction system after stirring is finished, reacting for 3h at 55 ℃, filtering and drying a product, and dispersing the product in distilled water to obtain a treating agent with the solid content of 8%;

processing treatment of die-casting die cavity of S3

And (3) immersing the pretreated die casting model into a treating agent, adjusting the pH value to 3, heating in a water bath to 75 ℃, stirring at a constant temperature for 5 hours, standing for 15 hours, taking out the treated die casting model, repeatedly washing with distilled water, and drying to complete the required treatment process.

Comparative example 1: process step S1.1) is removed, the rest being the same as in example 1.

Comparative example 2: the removal of the nano-titanium dioxide in process step S1.2) is identical to example 1.

Comparative example 3: the polyethylene wax is removed in process step S2.2) and the process is otherwise identical to example 1.

Comparative example 4: the removal of the magnesium borate nanowires in process step S2.2) is the same as in example 1.

Comparative example 5: the mercaptopropyltrimethoxysilane in process step S2.3) is removed, and the process is otherwise identical to example 1.

Comparative example 6: the process is the same as example 1 except that the hydrogen peroxide/glacial acetic acid mixed solution in the step S2.3) is removed.

Comparative example 7: the pH adjustment in process step S3.3) is eliminated, and the process is otherwise identical to example 1.

Control group: the die-casting mould cavity is only subjected to conventional impurity removal treatment.

Test experiments

Weighing 30 parts of talcum powder (nanoscale, 20nm in particle size), 20 parts of volcanic ash (600 meshes in fineness), 1 part of bentonite (180 nm in particle size), 3 parts of black corundum, 5 parts of polytetrafluoroethylene, 7 parts of titanium dioxide, 4 parts of silicon nitride powder, 16 parts of oxidized polyethylene wax (7000 in molecular weight) and 9 parts of aluminum dihydrogen phosphate according to parts by weight, adding the materials into a reaction kettle, mixing, stirring for 3 hours, and then ball-milling for 14 hours by using a ball mill to obtain a powdery mold release agent; processing a die-casting model by adopting the process methods provided by the embodiments 1-3, the comparative examples 1-7 and the comparison group to obtain a die-casting model sample, preheating at 200 ℃, atomizing a powdery mold release agent by a spray gun under the pressure of 5bar, spraying the atomized powdery mold release agent on a preheated die-casting mold cavity under the action of an electrostatic field, wherein the distance between the spray gun and the die-casting mold cavity is 13cm, the spraying time is 8s, the thickness of the sprayed mold release agent is 15 mu m, and the die-casting model sprayed with the powdery mold release agent is used for continuously manufacturing the aluminum alloy impeller, wherein in the manufacturing process, the casting temperature of the die-casting mold cavity is set to be 240 ℃, the mold release is easy to be carried out each time when the aluminum alloy impeller is released, the surface of the aluminum alloy impeller is smooth, the powdery mold release agent is regarded as meeting the requirement of continuous use until the aluminum alloy, stopping casting, recording the number of the manufactured aluminum alloy impellers meeting the requirements in the whole casting process, regarding the number of the turnover use times of a single group of the powder release agent, wherein the number of the die-casting model samples provided by each treatment process is 50, after the test is completed, calculating the average value of the turnover use times of the powder release agent, namely the turnover use times of the powder release agent under the treatment process condition, and recording the following results:

	example 1	Example 2	Example 3	Comparative example 1	Comparative example 2
						The turnover use frequency is improved by percent	28.6	29.3	28.9	8.6	0
	Comparative example 3	Comparative example 4	Comparative example 5	Comparative example 6	Comparative example 7
						The turnover use frequency is improved by percent	10.5	15.2	0	0	0
	Control group
						The turnover use frequency is improved by percent	0

Note: in the test process, the turnover energy use times obtained in the comparative examples 2, 5, 6 and 7 are compared with the control group, the change rate of the turnover times is less than 1%, and the change difference of the small amplitude is determined to belong to the normal fluctuation phenomenon in the die-casting manufacturing process by combining with the analysis of a specific theoretical basis, so that the reason why the treatment process of the die-casting mold cavity influences the test result is eliminated, and therefore, the turnover use time increase rate is set to be 0%, namely, the treatment process does not influence the final result.

In the invention, the turnover use times of the powdery release agent obtained in the embodiments 1 to 3 and the comparative examples 1 to 7 are compared with the control group, the change condition of the turnover use times is calculated, the action effect can be more intuitively reflected, and the comparison result shows that the process method provided by the invention can effectively improve the turnover use times of the release agent and realize the improvement of the service life of the powdery release agent.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that are not thought of through the inventive work should be included in the scope of the present invention.