阅读说明：本技术 一种镁合金压铸件的改性处理方法 (Modification treatment method for magnesium alloy die casting ) 是由 刘邵刚 邓荣辉 倪涛 李勇 于 2019-12-11 设计创作，主要内容包括：本发明提供了一种镁合金压铸件的改性处理方法,所述镁合金压铸件的改性处理方法的步骤如下：加入硅相重新熔炼,均匀化退火,清洗打磨,冷喷涂层,稳定后冷却,电镀防腐层,电泳颜料层,烘干保存,烘干保存。本申请在制备好的Mg-xAl-yCu-zZn合金熔体中加入固态Al-12.6Si共晶铝硅,加入了细小硅相,提高了硬度,重新熔炼并均匀化退火,使得镁合金压铸件成分均匀,冷喷涂纳米Al-Zn-Si合金涂层,提高了镁合金压铸件的耐腐蚀和耐磨性能,最后再对镁合金压铸件电镀防腐层、电泳颜料层,对镁合金压铸件进行全面防护,提高镁合金压铸件的抗腐蚀性。(The invention provides a modification treatment method of a magnesium alloy die casting, which comprises the following steps: adding silicon phase for remelting, homogenizing and annealing, cleaning and polishing, cold spraying a coating, cooling after stabilization, electroplating an anticorrosive layer, electroplating an electrophoretic pigment layer, drying and storing, and drying and storing. According to the method, solid Al-12.6Si eutectic aluminum silicon is added into a prepared Mg-xAl-yCu-zZn alloy melt, fine silicon phase is added, the hardness is improved, remelting and homogenizing annealing are carried out, so that the components of the magnesium alloy die casting are uniform, a nano Al-Zn-Si alloy coating is sprayed in a cold mode, the corrosion resistance and the wear resistance of the magnesium alloy die casting are improved, and finally an anti-corrosion layer and an electrophoretic pigment layer are electroplated on the magnesium alloy die casting, so that the magnesium alloy die casting is comprehensively protected, and the corrosion resistance of the magnesium alloy die casting is improved.)

1. A modification treatment method of a magnesium alloy die casting is characterized by comprising the following steps:

firstly, adding a silicon phase to smelt again, firstly preparing Mg-xAl-yCu-zZn alloy melt, then uniformly mixing the Mg-xAl-yCu-zZn alloy melt with Al-12.6Si intermediate alloy at the smelting temperature, pouring the mixture into a room-temperature metal casting mold, and preparing a Mg-11Al-1.0Cu-0.05Zn-mSi magnesium alloy die casting;

step two, carrying out homogenizing annealing, namely carrying out homogenizing annealing on the magnesium alloy die casting obtained in the step one to obtain a magnesium alloy die casting after homogenizing annealing;

cleaning and polishing, namely cleaning the surface of the magnesium alloy die casting subjected to homogenizing annealing obtained in the step two, and polishing the surface of the magnesium alloy die casting subjected to homogenizing annealing to obtain a magnesium alloy die casting subjected to surface treatment;

step four, cold spraying a coating, namely preparing a nano Al-Zn-Si alloy coating on the surface of the magnesium alloy die casting obtained in the step four by adopting cold spraying, wherein the mass ratio of Al to Zn to Si is 1: 3: 0.2: the magnesium alloy die casting is fixed and is sprayed by a spray gun in a straight line;

step five, cooling after stabilization, namely cooling the magnesium alloy die casting obtained in the step five to normal temperature in a nitrogen environment after heat preservation treatment is carried out on the magnesium alloy die casting in a heat preservation box for 1-3 h;

step six, electroplating an anticorrosive layer, namely placing the magnesium alloy die casting obtained in the step five in an electrolyte solution, taking the magnesium alloy die casting as a cathode, forming a coating on the surface of the magnesium alloy die casting under the action of external current, coating a layer of preservative on the surface of the aluminum alloy after electroplating, and cooling and solidifying the aluminum alloy die casting;

step seven, the electrophoretic pigment layer is used for placing the magnesium alloy die casting as one electrode into conductive aqueous solution or water-emulsified paint, forming an electrolytic circuit with the other electrode in the paint, and electrophoresing charged resin ions and adsorbed pigment particles onto the surface of a workpiece to form a coating so as to finish the electrophoretic work of the magnesium alloy die casting;

and step eight, drying and storing, namely drying the magnesium alloy die casting obtained in the step six in a drying box, and storing in a warehouse.

2. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: the smelting temperature in the first step is 600-700 ℃, and m is 0.5-1.1.

3. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: the homogenizing annealing process in the second step comprises the steps of annealing at the temperature of 400-450 ℃ under the pressure of 0.01-0.03Pa for 15-20 h.

4. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: and in the third step, 600-800-mesh sand paper is adopted for grinding and polishing.

5. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: in the fourth step, the spraying gas adopts nitrogen, the temperature of the carrier gas is 500-600 ℃, the powder feeding pressure is 5-7 MPa, the spraying distance is 20-35mm, the gas flow is 60-70m3/hr, and the powder feeding amount is 0.5-1m 3/hr.

6. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: the temperature range of the heat preservation box in the step five is 150-200 ℃, and the heat preservation time is 1-3 h.

7. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: in the sixth step, the electrolyte solution is metal, alloy and semiconductor particles, and after electroplating, different coatings can be formed on the coatings according to different solution particles.

8. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: and sixthly, placing the magnesium alloy die casting in the electrolyte solution for 4-8h to finish electroplating.

9. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: and step seven, under the action of an electric field, dissociating the coating solution into charged resin ions, moving positive ions to a negative electrode and negative ions to a positive electrode, and electrophoresing the charged resin ions and the adsorbed pigment particles onto the surface of the magnesium alloy die casting to form a coating.

10. The modification processing method of the magnesium alloy die casting according to claim 1, characterized in that: and the drying temperature in the step eight is 70-90 ℃, and the drying time is 1 h.

Technical Field

The invention relates to the technical field of metal treatment, in particular to a modification treatment method of a magnesium alloy die casting.

Background

The magnesium alloy has the characteristics of light weight, recoverability and the like, is widely applied to the fields of electronic equipment, automobiles and the like, and gradually becomes an ideal material of modern industrial products. With the continuous expansion of the application range of magnesium alloys, the usage amount of the magnesium alloys is rapidly increased, and the magnesium industry is growing at a high speed in geometric series. However, since magnesium is an active metal, the surface thereof is easily oxidized and has poor corrosion resistance, it is necessary to perform appropriate surface treatment of the magnesium alloy die casting according to specific requirements before use. In the production cost of the magnesium alloy die casting, the surface treatment accounts for about 40 percent, so the surface treatment is important for the production and application of the magnesium alloy die casting. At present, the research on the surface treatment of the magnesium alloy die casting is different, and the research is not as mature and standard as the surface treatment of the aluminum alloy die casting, which restricts the application of the magnesium alloy to a certain extent. Therefore, a method of treating a magnesium alloy die cast article must be studied to improve hardness and corrosion resistance.

Disclosure of Invention

The invention provides a modification treatment method of a magnesium alloy die casting, aiming at overcoming the problems of insufficient hardness and corrosion resistance of the magnesium alloy die casting in the prior art.

A modification treatment method of a magnesium alloy die casting comprises the following steps:

firstly, adding a silicon phase to smelt again, firstly preparing Mg-xAl-yCu-zZn alloy melt, then uniformly mixing the Mg-xAl-yCu-zZn alloy melt with Al-12.6Si intermediate alloy at the smelting temperature, pouring the mixture into a room-temperature metal casting mold, and preparing a Mg-11Al-1.0Cu-0.05Zn-mSi magnesium alloy die casting;

step two, carrying out homogenizing annealing, namely carrying out homogenizing annealing on the magnesium alloy die casting obtained in the step one to obtain a magnesium alloy die casting after homogenizing annealing;

cleaning and polishing, namely cleaning the surface of the magnesium alloy die casting subjected to homogenizing annealing obtained in the step two, and polishing the surface of the magnesium alloy die casting subjected to homogenizing annealing to obtain a magnesium alloy die casting subjected to surface treatment;

step four, cold spraying a coating, namely preparing a nano Al-Zn-Si alloy coating on the surface of the magnesium alloy die casting obtained in the step four by adopting cold spraying, wherein the mass ratio of Al to Zn to Si is 1: 3: 0.2: the magnesium alloy die casting is fixed and is sprayed by a spray gun in a straight line;

step five, cooling after stabilization, namely cooling the magnesium alloy die casting obtained in the step five to normal temperature in a nitrogen environment after heat preservation treatment is carried out on the magnesium alloy die casting in a heat preservation box for 1-3 h;

step six, electroplating an anticorrosive layer, namely placing the magnesium alloy die casting obtained in the step five in an electrolyte solution, taking the magnesium alloy die casting as a cathode, forming a coating on the surface of the magnesium alloy die casting under the action of external current, coating a layer of preservative on the surface of the aluminum alloy after electroplating, and cooling and solidifying the aluminum alloy die casting;

step seven, the electrophoretic pigment layer is used for placing the magnesium alloy die casting as one electrode into conductive aqueous solution or water-emulsified paint, forming an electrolytic circuit with the other electrode in the paint, and electrophoresing charged resin ions and adsorbed pigment particles onto the surface of a workpiece to form a coating so as to finish the electrophoretic work of the magnesium alloy die casting;

and step eight, drying and storing, namely drying the magnesium alloy die casting obtained in the step six in a drying box, and storing in a warehouse.

In a preferred embodiment of the present invention, the melting temperature in the first step is 600-700 ℃, and m is 0.5-1.1.

In a preferred embodiment of the present invention, the homogenizing annealing process in the second step is performed under an annealing pressure of 0.01-0.03Pa, an annealing temperature of 400-450 ℃ and an annealing time of 15-20 h.

In a preferred embodiment of the present invention, in the third step, 600-800 mesh sand paper is used for grinding and polishing.

In a preferred embodiment of the invention, in the fourth step, the spraying gas adopts nitrogen, the temperature of the carrier gas is 500-600 ℃, the powder feeding pressure is 5-7 MPa, the spraying distance is 20-35mm, the gas flow is 60-70m3/hr, and the powder feeding amount is 0.5-1m 3/hr.

In a preferred embodiment of the invention, the temperature range of the heat preservation box in the step five is 150-.

In a preferred embodiment of the present invention, the electrolyte solution in the sixth step is metal, alloy, or semiconductor particles, and after the electroplating is completed, the plating layer can form different plating layers according to different solution particles.

In a preferred embodiment of the invention, in the sixth step, the magnesium alloy die casting is placed in the electrolyte solution for 4-8 hours to complete the electroplating work.

In a preferred embodiment of the invention, in the seventh step, under the action of the electric field, the coating solution is dissociated into charged resin ions, the cations move to the cathode, the anions move to the anode, and the charged resin ions, together with adsorbed pigment particles, are electrophoresed onto the surface of the magnesium alloy die casting to form the coating.

In a preferred embodiment of the present invention, the drying temperature in the step eight is 70-90 ℃, and the drying time is 1 h.

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

(1) solid Al-12.6Si eutectic aluminum silicon is added into a prepared Mg-xAl-yCu-zZn alloy melt, fine silicon phase is added, the hardness is improved, remelting and homogenizing annealing are carried out, so that the components of a magnesium alloy die casting are uniform, a nano Al-Zn-Si alloy coating is sprayed in a cold mode, the corrosion resistance and the wear resistance of the magnesium alloy die casting are improved, and finally an anti-corrosion layer and an electrophoretic pigment layer are electroplated on the magnesium alloy die casting to protect the magnesium alloy die casting comprehensively and improve the corrosion resistance of the magnesium alloy die casting;

(2) solid Al-12.6Si eutectic aluminum silicon is adopted to introduce a large amount of fine silicon phases into the magnesium alloy die casting, so that the toughness is ensured and the alloy hardness is obviously improved;

(3) the performance of the magnesium alloy die casting is improved through reasonable process setting and process parameter configuration, and the performance, particularly the hardness, the wear resistance and the corrosion resistance, of the magnesium alloy die casting is improved.

Drawings

FIG. 1 is a schematic flow chart of a modification treatment method of a magnesium alloy die casting according to a preferred embodiment of the invention.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, a schematic flow chart of a preferred embodiment of a modification treatment method for a magnesium alloy die casting according to the present invention is shown, and the modification treatment method for the magnesium alloy die casting includes the following steps:

firstly, adding a silicon phase to smelt again, firstly preparing Mg-xAl-yCu-zZn alloy melt, then uniformly mixing the Mg-xAl-yCu-zZn alloy melt with Al-12.6Si intermediate alloy at the smelting temperature, pouring the mixture into a room-temperature metal casting mold, and preparing a Mg-11Al-1.0Cu-0.05Zn-mSi magnesium alloy die casting;

step two, carrying out homogenizing annealing, namely carrying out homogenizing annealing on the magnesium alloy die casting obtained in the step one to obtain a magnesium alloy die casting after homogenizing annealing;

cleaning and polishing, namely cleaning the surface of the magnesium alloy die casting subjected to homogenizing annealing obtained in the step two, and polishing the surface of the magnesium alloy die casting subjected to homogenizing annealing to obtain a magnesium alloy die casting subjected to surface treatment;

step four, cold spraying a coating, namely preparing a nano Al-Zn-Si alloy coating on the surface of the magnesium alloy die casting obtained in the step four by adopting cold spraying, wherein the mass ratio of Al to Zn to Si is 1: 3: 0.2: the magnesium alloy die casting is fixed and is sprayed by a spray gun in a straight line;

step five, cooling after stabilization, namely cooling the magnesium alloy die casting obtained in the step five to normal temperature in a nitrogen environment after heat preservation treatment is carried out on the magnesium alloy die casting in a heat preservation box for 1-3 h;

step six, electroplating an anticorrosive layer, namely placing the magnesium alloy die casting obtained in the step five in an electrolyte solution, taking the magnesium alloy die casting as a cathode, forming a coating on the surface of the magnesium alloy die casting under the action of external current, coating a layer of preservative on the surface of the aluminum alloy after electroplating, and cooling and solidifying the aluminum alloy die casting;

step seven, the electrophoretic pigment layer is used for placing the magnesium alloy die casting as one electrode into conductive aqueous solution or water-emulsified paint, forming an electrolytic circuit with the other electrode in the paint, and electrophoresing charged resin ions and adsorbed pigment particles onto the surface of a workpiece to form a coating so as to finish the electrophoretic work of the magnesium alloy die casting;

and step eight, drying and storing, namely drying the magnesium alloy die casting obtained in the step six in a drying box, and storing in a warehouse.

In this embodiment, the melting temperature in the first step is 600-700 ℃, and m is 0.5-1.1.

In this embodiment, the homogenizing annealing process in the second step is performed under an annealing pressure of 0.01-0.03Pa, an annealing temperature of 400-450 ℃ and an annealing time of 15-20 h.

In this embodiment, in the third step, 600-800-mesh sand paper is used for grinding and polishing.

In the fourth step, nitrogen is used as the spraying gas, the temperature of the carrier gas is 500-600 ℃, the powder feeding pressure is 5-7 MPa, the spraying distance is 20-35mm, the gas flow is 60-70m3/hr, and the powder feeding amount is 0.5-1m 3/hr.

In this embodiment, the temperature range of the heat preservation box in the fifth step is 150-.

In this embodiment, the electrolyte solution in the sixth step is metal, alloy, and semiconductor particles, and after the electroplating is completed, the plating layer may form different plating layers according to different solution particles.

In the embodiment, in the sixth step, the magnesium alloy die casting is placed in the electrolyte solution for 4-8 hours to complete the electroplating work.

In the present embodiment, in the seventh step, under the action of the electric field, the coating solution is dissociated into charged resin ions, cations move to the cathode, anions move to the anode, and the charged resin ions, together with adsorbed pigment particles, are electrophoresed onto the surface of the magnesium alloy die casting to form the coating.

In this embodiment, the drying temperature in the step eight is 70-90 ℃, and the drying time is 1 h.

Solid Al-12.6Si eutectic aluminum silicon is added into a prepared Mg-xAl-yCu-zZn alloy melt, fine silicon phase is added, the hardness is improved, remelting and homogenizing annealing are carried out, so that the components of a magnesium alloy die casting are uniform, a nano Al-Zn-Si alloy coating is sprayed in a cold mode, the corrosion resistance and the wear resistance of the magnesium alloy die casting are improved, and finally an anti-corrosion layer and an electrophoretic pigment layer are electroplated on the magnesium alloy die casting to protect the magnesium alloy die casting comprehensively and improve the corrosion resistance of the magnesium alloy die casting; solid Al-12.6Si eutectic aluminum silicon is adopted to introduce a large amount of fine silicon phases into the magnesium alloy die casting, so that the toughness is ensured and the alloy hardness is obviously improved; the performance of the magnesium alloy die casting is improved through reasonable process setting and process parameter configuration, and the performance, particularly the hardness and the corrosion resistance, of the magnesium alloy die casting is improved.

While the foregoing description shows and describes the preferred embodiments of the present invention, it is to be understood that the invention is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.