CN112247097B - Semi-solid die-casting and double-fluorination combined manufacturing method for magnesium alloy building template - Google Patents

Abstract

The invention discloses a semi-solid die-casting and double-fluorination combined manufacturing method of a magnesium alloy building template, which comprises the following steps of: step one, preparing a magnesium alloy building template by adopting a semi-solid die-casting method; and step two, immersing the magnesium alloy building template prepared in the step one into a difluoride treatment liquid for difluoride combined treatment to obtain the magnesium alloy building template subjected to the difluoride combined treatment. The magnesium alloy template manufactured by the invention has the advantages of flat and defect-free surface, high tensile strength, large elongation, high surface hardness, small friction coefficient, excellent scratch resistance and hydrophobicity, can effectively reduce friction damage caused by concrete aggregate and corrosion damage from external erosion media, prevents chemical reaction and physical adsorption caused by cement, and ensures the construction quality of building wall surfaces and demoulding effect.

Description

Semi-solid die-casting and double-fluorination combined manufacturing method for magnesium alloy building template

Technical Field

The invention belongs to the field of concrete engineering construction template preparation, and particularly relates to a semi-solid die-casting and double-fluorination combined manufacturing method for a magnesium alloy building template.

Background

Concrete form work is one of the leading works in building construction. The template is an important turnover material in concrete structure engineering construction and is an important factor for determining the concrete forming quality, the formwork supporting working strength, the construction efficiency and the cost. In recent years, in order to better promote the efficient development of the concrete construction industry in China, China establishes the development of a novel template application technology as one of 10 new technologies in the building industry, which is enough to show that the country pays high attention to the innovation and development of the template industry, and meanwhile, related documents are issued in various places to promote the development of novel environment-friendly templates, such as 'Chongqing City construction field prohibition and use restriction behind technology announcement (2019 edition)' and 'building engineering fair-faced concrete construction technology standard (solicited suggestion draft)' issued in 11, 6 and 11, 15 days in 2019 in Chongqing City. The template material is the most important research content of the concrete construction technology and is also the key factor for realizing the reformation of the template system. Therefore, research effort is urgently needed to be increased, more novel template materials are developed, the quality, the progress and the cost of template engineering construction are guaranteed, and new requirements of environmental protection, economic sustainable development and the like are met.

The density of the magnesium alloy is only 2/3 of aluminum alloy, and the specific strength and specific rigidity of steel is 1/4 of steel and iron alloy which are both superior to steel and aluminum alloy and far higher than engineering plastics; the magnesium alloy has strong shock absorption performance, reduces the impact of concrete pouring and reduces the construction noise; the casting performance is good, the automatic production capacity and the service life of the die are high, and the die casting process can be favorably adopted for automatic production; the magnesium alloy has stable size, does not cause great change due to the change of the environmental temperature and the time, and can prevent the difficult problem of template splicing caused by deformation. Therefore, in the field of concrete construction formwork engineering, the magnesium alloy is a high-quality light structural material which cannot be compared with the above materials.

For magnesium alloy building templates, only chinese patent application No. 201510869825.1 and chinese patent application No. 201910780290.9 have reported on them at present. In the patent application, the magnesium alloy template is manufactured by adopting the traditional extrusion process and the traditional die-casting process. The extrusion process is difficult to realize the integral manufacture of the magnesium alloy template, and the welding process is required to manufacture the template available on site, but the existing welding process is difficult to realize the reliable template manufacture due to the characteristics of the magnesium alloy material. The magnesium alloy template is die-cast by utilizing the traditional die-casting technology, so that the problems that gas in a cavity exists in the template and the gas generated by die-casting coating cannot be smoothly discharged are easily caused, and the gas is dissolved in the magnesium alloy under high pressure or forms a plurality of high-pressure micro-pores which are dispersed and distributed in the die-casting template.

In addition, the magnesium alloy die-casting template is easily corroded by atmosphere and water environment in the processes of storage and use, and the surface of the template is easily scratched by concrete in the construction process, so that the problem that the template is adhered to the concrete and is difficult to fall off is caused in both cases, and the quality of the formed surface of the concrete is further influenced; the existing surface treatment method is difficult to effectively solve the problems existing on the surface of the magnesium alloy building template.

Disclosure of Invention

The invention aims to provide a semi-solid die-casting and double-fluorination combined manufacturing method for a magnesium alloy building template, which is used for meeting the technical requirements of fair-faced concrete and veneer fair-faced concrete on the template.

In order to achieve the purpose, the invention adopts the following technical scheme:

a magnesium alloy building template semi-solid state die casting and double fluorination combined manufacturing method comprises the following steps:

step one, preparing a magnesium alloy building template by adopting a semi-solid die-casting method;

and step two, immersing the magnesium alloy building template prepared in the step one into a difluoride treatment liquid for difluoride combined treatment to obtain the magnesium alloy building template subjected to the difluoride combined treatment.

The invention further improves the following steps: the difluoride treatment liquid comprises the following components in percentage by weight: 20 to 30 percent of inorganic fluoride, 20 to 40 percent of organic fluorine-containing emulsion, 15 to 20 percent of nano silica sol, 0.3 to 0.5 percent of corrosion inhibitor component, 0.8 to 2 percent of silane coupling agent and 20 to 43.9 percent of deionized water.

The invention further improves the following steps: the inorganic fluoride is one or more of hydrofluoric acid, fluosilicic acid, fluotitanic acid, hypofluoric acid, hydrofluoride, fluosilicate, fluotitanate and hypofluorite.

The invention further improves the following steps: the organic fluorine-containing emulsion is an emulsion formed by blending fluorine-containing water-based resin and water-based epoxy resin, and the weight ratio of the fluorine-containing water-based resin to the water-based epoxy resin is 8:1-5: 1; the organic fluorine-containing emulsion has a self-crosslinking characteristic and a self-layering characteristic; the fluorine-containing water-based resin is one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, polytetrafluoroethylene modified polymer, polyvinylidene fluoride modified polymer, polyvinyl fluoride modified polymer, polychlorotrifluoroethylene modified polymer, ethylene-tetrafluoroethylene copolymer modified polymer and ethylene-chlorotrifluoroethylene copolymer modified polymer.

The invention further improves the following steps: the particle size of the nano silica sol is controlled to be 50-800 nm, wherein according to the mass percentage, the content of silicon dioxide in the silica sol is controlled to be 30-50%, the content of sodium oxide impurities is less than 0.2%, and the balance is water.

The invention further improves the following steps: the corrosion inhibitor component is one or more of metavanadate or metavanadate.

The invention further improves the following steps: the silane coupling agent is one or more of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane, gamma-aminopropyl triethoxy silane, gamma-methacryloxypropyl and gamma-mercaptopropyl trimethoxy silane.

The invention further improves the following steps: the second step specifically comprises:

immersing the magnesium alloy building template with a clean surface into the difluoride treatment liquid, controlling the working temperature of the treatment liquid to be 25-60 ℃, and treating for 10-60 min to prepare an initial film layer on the surface of the magnesium alloy building template; then cleaning, airing and drying at 60-80 ℃, forming a layer of double-fluorine composite film layer system with self-repairing function, which is composed of three layers of an inorganic fluorine layer, a transition layer and an organic fluorine layer, on the surface of the magnesium alloy building template, and obtaining the magnesium alloy building template treated by double-fluorine combination.

The invention further improves the following steps: the first step specifically comprises the following steps:

s1: preheating a mould;

s2: material preparation and heating: heating and melting magnesium alloy particles to form alloy semi-solid slurry;

s3: high-speed injection: closing the die, vacuumizing, and injecting the alloy semisolid slurry into a cavity of the preheating die at a high speed for molding;

s4: opening the mold and cooling: and opening the mold to eject the magnesium alloy building template.

The invention further improves the following steps: the first step specifically comprises the following steps:

s1: preheating a mould;

s2: material preparation and heating: putting magnesium alloy particles into a hopper through an automatic feeding system, forcibly conveying the magnesium alloy particles into a particle cylinder, driving the magnesium alloy particles to move towards a mold by a rotating screw in the particle cylinder, introducing argon for protection, heating to convert alloy raw materials in the particle cylinder into a partially molten state, forming alloy materials with dendritic crystal tissues into alloy semi-solid slurry with a thixotropic structure and the temperature of 570-590 ℃ under the shearing action of a spiral body, wherein the solid phase volume fraction is 50-60%;

s3: high-speed injection: closing the die, vacuumizing, injecting the alloy semi-solid slurry into a cavity of a preheating die at a high speed for molding by jointly controlling the speed and the pressure, wherein the pressure is controlled at 70-90 MPa and the speed is controlled at 2-6 m/s;

s4: opening the mold and cooling: and (4) the screw rod is retreated to measure the next injection material, the mold is opened to eject the magnesium alloy building template, and the template is subjected to air cooling or water cooling and natural cooling.

Compared with the prior art, the invention has the following beneficial effects:

the magnesium alloy template manufactured by the invention has smooth and flat surface, high tensile strength, large elongation, high hardness, small friction coefficient, excellent scratch resistance and hydrophobicity, can effectively reduce the friction damage caused by concrete aggregate and the corrosion damage from external erosion medium, prevents the chemical reaction and physical adsorption caused by cement, and ensures the construction quality of building wall surfaces and the demoulding effect.

Compared with the prior art, the magnesium alloy building template manufactured by adopting the semi-solid die casting and double-fluorination combined manufacturing method has a stable double-fluorine three-layer composite protective film layer system on the surface, the template has smooth and flat surface, high tensile strength (up to 256MPa), large elongation (up to more than 11%), high hardness (more than 4H), small friction coefficient (the dry friction coefficient can be as low as 0.04), greatly improved hydrophobicity (the contact angle can be more than 114 degrees), meanwhile, the neutral salt spray resistance experiment can reach more than 840 hours, so that the friction damage of concrete aggregate to the template and the corrosion damage from external erosion media can be effectively reduced, the chemical reaction and physical adsorption of cement and the template are prevented, the construction quality of the building wall surface and the demolding effect are ensured, and the technical requirements of the fair-faced concrete and the veneer fair-faced concrete on the template can be effectively met.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view of a magnesium alloy template manufactured by the semi-solid die casting and double-fluorination combined manufacturing method of the invention.

FIG. 2 is a process flow chart of the semi-solid die casting and double-fluorination combined manufacturing method of the magnesium alloy template.

FIG. 3 is a schematic view of a dual-fluorine three-layer composite protective film system on the surface of a magnesium alloy template according to the present invention.

FIG. 4 is a surface micro-topography of a magnesium alloy template in example 1 of the present invention;

fig. 5 is a contact angle diagram of the dual-fluorine three-layer composite protective film layer on the surface of the magnesium alloy template in example 1 of the present invention.

Detailed Description

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The following detailed description is exemplary in nature and is intended to provide further details of the invention. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the invention.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention relates to a semi-solid die-casting and double-fluorination combined manufacturing method of a magnesium alloy building template, which comprises the following steps of:

step one, preparing a magnesium alloy building template by adopting a semi-solid die-casting method;

and step two, immersing the magnesium alloy building template prepared in the step one into a difluoride treatment liquid for difluoride combined treatment to obtain the magnesium alloy building template subjected to the difluoride combined treatment.

In the invention, the difluoride treatment liquid comprises the following components in percentage by weight: 20 to 30 percent of inorganic fluoride, 20 to 40 percent of organic fluorine-containing emulsion, 15 to 20 percent of nano silica sol, 0.3 to 0.5 percent of corrosion inhibitor component, 0.8 to 2 percent of silane coupling agent and 20 to 43.9 percent of deionized water.

Example 1:

a semi-solid die-casting and double-fluorination combined manufacturing method of a magnesium alloy building template comprises the following operation steps:

s1: preheating an upper die, designing a die aiming at a template, and completing die opening and die testing according to the die processing technological process (sample piece-finished piece digital model-compiling stamping technology-die structure design-model making-machining-grinding assembly-die testing-final inspection). The template die is installed on a die-casting machine, the template die is connected with corresponding required peripheral equipment, a water-soluble release agent is sprayed on the die, and the template die is preheated by the die temperature machine when the die temperature requirement exists.

S2: preparing materials and heating, preparing magnesium alloy particles with the diameter of 3-5 mm and the length of about 10mm, putting the magnesium alloy particles into a hopper through an automatic feeding system, forcibly conveying the magnesium alloy particles into a particle cylinder, driving the magnesium alloy particles to move towards a mold through a rotating screw rod in the particle cylinder, introducing argon for protection, controlling the temperature to be 580 ℃ through resistance and induction heating, converting alloy raw materials in the particle cylinder into a partial melting state, and forming alloy semi-solid slurry with a thixotropic structure under the shearing action of a spiral body, wherein the solid phase volume fraction is 50%.

S3: and (3) high-speed injection, closing the template die, vacuumizing, and injecting the alloy semi-solid slurry into a cavity of the preheating die at a high speed by jointly controlling the speed and the pressure, wherein the pressure is controlled at 90MPa and the speed is controlled at 6 m/s.

S4: and opening the mold and cooling, retreating the screw to measure the next injection material, opening the mold to eject the template product, and carrying out air cooling on the template.

S5: carrying out bifluoride chemical treatment on the surface of the template: after the template is cooled, machining is performed, followed by specific bifluoride chemical surface treatment. The schematic diagram of the double-fluorine three-layer composite protective film layer system formed on the surface of the magnesium alloy template by the technology is shown in fig. 3. The composition (weight percentage) of the difluoride treating liquid used by the difluoride chemical surface treatment technology is as follows: 25 percent of hydrofluoric acid, 20 percent of organic fluorine-containing emulsion, 20 percent of 100-phase 200nm nanometer silica sol, 0.5 percent of potassium metavanadate corrosion inhibitor component, 2 percent of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent and 32.5 percent of deionized water.

Preparing the difluoride treatment liquid according to the composition proportion, firstly adding 20% of deionized water into a container, then adding 25% of hydrofluoric acid, uniformly stirring, then adding 0.5% of potassium metavanadate corrosion inhibitor component, uniformly stirring, then adding 2% of- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, synchronously adding 20% of 100-plus-200 nm-particle-size nano silica sol, stirring at normal temperature while adding 20% of organic fluorine-containing emulsion, supplementing the rest 12.5% of deionized water, and stirring for 5 hours to obtain the difluoride treatment liquid. The magnesium alloy template is AM50 series, and the magnesium alloy template is degreased by alkaline degreasing solution on the surface of magnesium alloy, which is well known by the technicians in the field, wherein the degreasing temperature is 60 ℃ and the time is 5 minutes; carrying out two times of deionized water washing; slowly immersing the template into a difluoride treatment solution to carry out difluoride chemical treatment, wherein the temperature of the treatment solution is 40 ℃, and the treatment time is 40 min; carrying out secondary deionized water washing for 2 times; naturally airing for 20 minutes, and continuously drying for 40 minutes in an oven at 80 ℃ to form a double-fluorine composite film layer system (shown in figure 3) with a self-repairing function, which is formed by three layers of an inorganic fluoride layer 2, a transition layer 3 and an organic fluoride layer 4, on the magnesium alloy building template 1. Nanometer sol particles 5 and slow-release molecules 6 are distributed in a layer system of the double-fluorine composite film. The micro-morphology of the obtained double-fluorine composite film layer is shown in figure 4.

Through an electrochemical tafel curve test in a 3.5% NaCl solution, the self-corrosion current density of the AM50 magnesium alloy template treated by the film layer is improved by more than 3 orders of magnitude relative to that of a blank magnesium alloy template, the test time of a non-grid-division neutral salt spray test can reach 840 hours without being damaged, the contact angle is 114 degrees (as shown in figure 5), the hardness is more than 4H, the dry friction coefficient is 0.04, the impact resistance is more than 50kg.cm, the tensile strength of the template is more than 256MPa, and the elongation is 11.2%.

Example 2:

a semi-solid die-casting and double-fluorination combined manufacturing method of a magnesium alloy building template comprises the following operation steps:

s1: preheating an upper die, designing a die aiming at a template, and completing die opening and die testing according to the die processing technological process (sample piece-finished piece digital model-compiling stamping technology-die structure design-model making-machining-grinding assembly-die testing-final inspection). The template die is installed on a die-casting machine, the template die is connected with corresponding required peripheral equipment, a water-soluble release agent is sprayed on the die, and the template die is preheated by the die temperature machine when the die temperature requirement exists.

S2: preparing materials and heating, preparing magnesium alloy particles with the diameter of 3-5 mm and the length of about 10mm, putting the magnesium alloy particles into a hopper through an automatic feeding system, forcibly conveying the magnesium alloy particles into a particle cylinder, driving the magnesium alloy particles to move towards a mold through a rotating screw rod in the particle cylinder, introducing argon for protection, controlling the temperature to be 570 ℃, converting alloy raw materials in the particle cylinder into a partial melting state through resistance and induction heating, and forming alloy semi-solid slurry with a thixotropic structure under the shearing action of a spiral body, wherein the solid phase volume fraction is 55%.

S3: and (3) high-speed injection, closing the template die, vacuumizing, and injecting the alloy semi-solid slurry into a cavity of the preheating die at a high speed by jointly controlling the speed and the pressure, wherein the pressure is controlled at 70MPa and the speed is controlled at 5 m/s.

S4: and opening the mold and cooling, retreating the screw to measure the next injection material, opening the mold to eject the template product, and carrying out air cooling and natural cooling on the template.

S5: carrying out bifluoride chemical treatment on the surface of the template: after the template is cooled, machining is performed, followed by specific bifluoride chemical surface treatment. The composition (weight percentage) of the difluoride treating liquid used by the difluoride chemical surface treatment technology is as follows: 22% of hydrofluoric acid, 30% of organic fluorine-containing emulsion, 16% of 100-phase 200 nm-particle-size nano silica sol, 0.3% of sodium metavanadate corrosion inhibitor component, 1% of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent and 30.7% of deionized water. Preparing the difluoride treatment liquid according to the composition proportion, firstly adding 24% of deionized water into a container, then adding 22% of hydrofluoric acid, uniformly stirring, then adding 0.3% of sodium metavanadate corrosion inhibitor component, uniformly stirring, then adding 1% of- (2, 3-epoxypropoxy) propyl trimethoxy silane coupling agent, synchronously adding 16% of 100-plus-200 nm-particle-size nano silica sol, stirring at normal temperature while adding 30% of organic fluorine-containing emulsion, supplementing the rest 6.7% of deionized water, and stirring for 4 hours to obtain the difluoride treatment liquid. The magnesium alloy template is AM50 series, and the magnesium alloy template is degreased by alkaline degreasing solution on the surface of magnesium alloy, which is well known by the technicians in the field, wherein the degreasing temperature is 60 ℃ and the time is 5 minutes; carrying out two times of deionized water washing; slowly immersing the template into a difluoride treatment solution for difluoride chemical treatment, wherein the temperature of the treatment solution is 45 ℃, and the treatment time is 40 min; carrying out secondary deionized water washing for 2 times; naturally airing for 30 minutes, and continuously drying for 40 minutes in an oven at 80 ℃ to obtain the difluoride composite film layer.

Through an electrochemical tafel curve test in a 3.5% NaCl solution, the self-corrosion current density of the AM50 magnesium alloy template treated by the film layer is improved by nearly 3 orders of magnitude relative to that of a blank magnesium alloy template, the test time of a non-grid-division neutral salt spray test can reach 720 hours without being damaged, the contact angle is 95 degrees, the hardness is 4H, the dry friction coefficient is 0.05, the impact resistance is more than 50kg.cm, the tensile strength of the template is 235MPa, and the elongation is 9.8%.

Example 3:

a semi-solid die-casting and double-fluorination combined manufacturing method of a magnesium alloy building template comprises the following operation steps:

s1: preheating an upper die, designing a die aiming at a template, and completing die opening and die testing according to the die processing technological process (sample piece-finished piece digital model-compiling stamping technology-die structure design-model making-machining-grinding assembly-die testing-final inspection). The template die is installed on a die-casting machine, the template die is connected with corresponding required peripheral equipment, a water-soluble release agent is sprayed on the die, and the template die is preheated by the die temperature machine when the die temperature requirement exists.

S2: preparing materials and heating, preparing magnesium alloy particles with the diameter of 3-5 mm and the length of about 10mm, putting the magnesium alloy particles into a hopper through an automatic feeding system, forcibly conveying the magnesium alloy particles into a particle cylinder, driving the magnesium alloy particles to move towards a mold through a rotating screw rod in the particle cylinder, introducing argon for protection, controlling the temperature to be 590 ℃, converting alloy raw materials in the particle cylinder into a partial melting state, and forming alloy semi-solid slurry with a thixotropic structure under the shearing action of a spiral body, wherein the solid phase volume fraction is 60%.

S3: and (3) high-speed injection, closing the template die, vacuumizing, and injecting the alloy semi-solid slurry into a cavity of the preheating die at a high speed by jointly controlling the speed and the pressure, wherein the pressure is controlled at 80MPa and the injection force is controlled at 2 m/s.

S4: and opening the mold and cooling, retreating the screw to measure the next injection material, opening the mold to eject the template product, and carrying out air cooling and natural cooling on the template.

S5: carrying out bifluoride chemical treatment on the surface of the template: after the template is cooled, machining is performed, followed by specific bifluoride chemical surface treatment. The composition (weight percentage) of the difluoride treating liquid used by the difluoride chemical surface treatment technology is as follows: 20% of hydrofluoric acid, 35% of organic fluorine-containing emulsion, 15% of 100-one nano-silica sol with the particle size of 200nm, 0.4% of potassium metavanadate corrosion inhibitor component, 1.5% of gamma-mercaptopropyl trimethoxysilane coupling agent and 28.1% of deionized water. Preparing the difluoride treatment liquid according to the composition proportion, firstly adding 20% of deionized water into a container, then adding 20% of hydrofluoric acid, uniformly stirring, then adding 0.4% of potassium metavanadate corrosion inhibitor component, uniformly stirring, then adding 1.5% of gamma-mercaptopropyltrimethoxysilane coupling agent, synchronously adding 15% of 100-plus 200 nm-particle-size nano silica sol, adding 35% of organic fluorine-containing emulsion at normal temperature while stirring, supplementing the rest 8.1% of deionized water, and stirring for 4 hours to obtain the needed difluoride treatment liquid. The magnesium alloy template is AM50 series, and the magnesium alloy template is degreased by alkaline degreasing solution on the surface of magnesium alloy, which is well known by the technicians in the field, wherein the degreasing temperature is 70 ℃ and the time is 3 minutes; carrying out two times of deionized water washing; slowly immersing the template into a difluoride treatment solution for difluoride chemical treatment, wherein the temperature of the treatment solution is 50 ℃, and the treatment time is 30 min; carrying out secondary deionized water washing for 2 times; naturally airing for 10 minutes, and continuously drying for 40 minutes in an oven at 80 ℃ to obtain the difluoride film layer. Through an electrochemical tafel curve test in a 3.5% NaCl solution, the self-corrosion current density of the AM50 magnesium alloy template treated by the film layer is improved by more than 2 orders of magnitude relative to that of a blank magnesium alloy template, the test time of a non-grid-division neutral salt spray test can reach 648 hours without damage, the contact angle is 90 degrees, the hardness is more than 4H, the dry friction coefficient is 0.05, the impact resistance is more than 50kg.cm, the tensile strength of the template is 238MPa, and the elongation is 10.2%.

It will be appreciated by those skilled in the art that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed above are therefore to be considered in all respects as illustrative and not restrictive. All changes which come within the scope of or equivalence to the invention are intended to be embraced therein.

Claims (4)

1. A magnesium alloy building template semi-solid state die casting and double fluorination combined manufacturing method is characterized by comprising the following steps:

step one, preparing a magnesium alloy building template by adopting a semi-solid die-casting method;

step two, immersing the magnesium alloy building template prepared in the step one into a difluoride treatment liquid to carry out difluoride combined treatment to obtain a magnesium alloy building template subjected to the difluoride combined treatment;

the difluoride treatment liquid comprises the following components in percentage by weight: 20 to 30 percent of inorganic fluoride, 20 to 40 percent of organic fluorine-containing emulsion, 15 to 20 percent of nano silica sol, 0.3 to 0.5 percent of corrosion inhibitor component, 0.8 to 2 percent of silane coupling agent and 20 to 43.9 percent of deionized water;

the inorganic fluoride is hydrofluoric acid;

the organic fluorine-containing emulsion is an emulsion formed by blending fluorine-containing water-based resin and water-based epoxy resin, and the weight ratio of the fluorine-containing water-based resin to the water-based epoxy resin is 8:1-5: 1; the organic fluorine-containing emulsion has a self-crosslinking characteristic and a self-layering characteristic; the fluorine-containing water-based resin is one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, polytetrafluoroethylene modified polymer, polyvinylidene fluoride modified polymer, polyvinyl fluoride modified polymer, polychlorotrifluoroethylene modified polymer, ethylene-tetrafluoroethylene copolymer modified polymer and ethylene-chlorotrifluoroethylene copolymer modified polymer;

the particle size of the nano silica sol is controlled to be 50nm-800nm, wherein according to the mass percentage, the content of silicon dioxide in the silica sol is controlled to be 30-50%, the content of sodium oxide impurities is less than 0.2%, and the balance is water;

the corrosion inhibitor component is one or more of metavanadate or metavanadate;

the silane coupling agent is one or more of gamma- (2, 3-epoxypropoxy) propyl trimethoxy silane, gamma-aminopropyl triethoxy silane, gamma-methacryloxypropyl and gamma-mercaptopropyl trimethoxy silane.

2. The semi-solid die-casting and double-fluorination combined manufacturing method of the magnesium alloy building template according to claim 1, wherein the second step specifically comprises:

immersing the magnesium alloy building template with a clean surface into the difluoride treatment liquid, controlling the working temperature of the treatment liquid to be 25-60 ℃, and treating for 10-60 min to prepare an initial film layer on the surface of the magnesium alloy building template; then cleaning, airing and drying at 60-80 ℃, forming a layer of double-fluorine composite film layer system with self-repairing function, which is composed of three layers of an inorganic fluorine layer, a transition layer and an organic fluorine layer, on the surface of the magnesium alloy building template, and obtaining the magnesium alloy building template treated by double-fluorine combination.

3. The semi-solid die-casting and double-fluorination combined manufacturing method of the magnesium alloy building template according to claim 1, wherein the first step specifically comprises:

s1: preheating a mould;

s2: material preparation and heating: heating and melting magnesium alloy particles to form alloy semi-solid slurry;

s3: high-speed injection: closing the die, vacuumizing, and injecting the alloy semisolid slurry into a cavity of the preheating die at a high speed for molding;

s4: opening the mold and cooling: and opening the mold to eject the magnesium alloy building template.

4. The semi-solid die-casting and double-fluorination combined manufacturing method of the magnesium alloy building template according to claim 1, wherein the first step specifically comprises:

s1: preheating a mould;

s2: material preparation and heating: putting magnesium alloy particles into a hopper through an automatic feeding system, forcibly conveying the magnesium alloy particles into a particle cylinder, driving the magnesium alloy particles to move towards a mold by a rotating screw in the particle cylinder, introducing argon for protection, heating to convert alloy raw materials in the particle cylinder into a partially molten state, forming alloy materials with dendritic crystal tissues into alloy semi-solid slurry with a thixotropic structure and the temperature of 570-590 ℃ under the shearing action of a spiral body, wherein the solid phase volume fraction is 50-60%;

s3: high-speed injection: closing the die, vacuumizing, injecting the alloy semi-solid slurry into a cavity of a preheating die at a high speed for molding by jointly controlling the speed and the pressure, wherein the pressure is controlled at 70-90 MPa and the speed is controlled at 2-6 m/s;

s4: opening the mold and cooling: and (4) the screw rod is retreated to measure the next injection material, the mold is opened to eject the magnesium alloy building template, and the template is subjected to air cooling or water cooling and natural cooling.

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