CN111926285A

CN111926285A - Method for preparing zinc-aluminum-magnesium powder zincizing agent and treating steel

Info

Publication number: CN111926285A
Application number: CN202010607059.2A
Authority: CN
Inventors: 王鑫铭; 陈夏琪; 文涛; 李小波
Original assignee: Xiangtan University
Current assignee: Xiangtan University
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2020-11-13

Abstract

The invention discloses a method for preparing a zinc-aluminum-magnesium powder zincizing agent and a method for treating steel. The raw materials are 30-60% of zinc powder, 20-40% of 5083 magnesium aluminum alloy powder, 1-3% of ammonium chloride and the balance of aluminum oxide according to the weight percentage. Wherein 5083 the magnesium-containing aluminum alloy powder comprises the following components: 4.0 to 4.9 percent of Mg, 93 to 96 percent of Al, and the granularity of 100 to 200 meshes. And (3) carrying out oil removal and rust removal treatment on the metal matrix, and then carrying out zinc impregnation treatment in a vacuum environment, wherein the annealing temperature is 420-470 ℃ and the annealing time is 3-5 h. After cooling, the matrix after zincification is passivated, the hardness of the cementation layer is 278.92HV, and the depth of the cementation layer can reach 65 μm. The zinc-aluminum-magnesium powder zincing agent can effectively inhibit grain boundary corrosion and better improve salt-containing atmosphere corrosion resistance, and the zincing method has the advantages of simple operation, low cost and green and pollution-free production process, and can prepare a high-quality zinc impregnation layer with high bonding strength with parts and excellent wear resistance.

Description

Method for preparing zinc-aluminum-magnesium powder zincizing agent and treating steel

Technical Field

The invention relates to a surface modification technology of a metal matrix, in particular to a zinc-aluminum-magnesium powder zincizing agent and a method for treating steel by using the same.

Background

Metal parts, especially parts such as fasteners and the like, are widely applied in the industries such as automobiles, bridges, military weapons, hardware and the like, and the steel parts are often in severe environments and are eroded by atmosphere and seawater, so that an anti-corrosion method with stable properties is often needed, and the anti-corrosion capability of the parts is improved. Galvanization and zincification on the surface of steel are one of the most common surface anti-rust methods in use today.

With the continuous development of metal materials and industrial technologies, various countries have made higher demands for long-term and inexpensive rust prevention technologies for metal products. Surface modification is the most common method for preventing corrosion of materials, and the method for isolating metal materials from the environment slows down the oxidation rate and improves the corrosion resistance of the materials.

The surface modification is to change the state of the surface structure of the matrix, thereby not only exerting the mechanical property of the material matrix, but also meeting the use requirements of the surface of the part. Hot dip galvanization is one of the most widely used surface modification processes for steel parts. However, the existing hot-dip galvanizing process used in China has large energy consumption and poor coating corrosion resistance and other properties, and is difficult to meet the use requirements of parts in parts with severe environments. Therefore, the powder zinc impregnation technology is adopted in China, so that the corrosion resistance of metal parts is improved.

Powder zincing is a thermal diffusion surface strengthening technique, which is a chemical heat treatment in the ferrite state. A method for the infiltration of zinc into the surface of steel at a temperature below Ac1 and substantially without phase transformation of the matrix in the steel. The zincated layer tends to have excellent corrosion resistance as well as good wear resistance.

The hot dip galvanizing aluminum magnesium technology has already been commercialized internationally, and the corrosion resistance of an aluminum coating can be better utilized when high-content aluminum elements are added into the coating, and the corrosion resistance of the aluminum coating is good in salt-containing atmosphere. The addition of Mg can form a stable Zn and ZnAl protective layer on the surface of the coating, and effectively inhibit grain boundary corrosion, thereby improving the corrosion resistance of the Zn-Al coating. However, the increase of the aluminum content easily causes the occurrence of powder zinc impregnation on the coating as a novel surface treatment method, has the characteristics of simple operation, low cost, green and pollution-free production process and the like, and greatly reduces the risk of hydrogen embrittlement of steel parts due to lower treatment temperature, so that a high-quality zinc impregnation layer with high bonding strength with parts and excellent wear resistance can be prepared.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the existing powder zincizing component has poor corrosion performance in a salt-containing atmosphere, and the powder zinc-plating aluminum magnesium process has large energy consumption.

In order to solve the technical problems, the technical scheme of the invention is a method for preparing a zinc-aluminum-magnesium powder zincizing agent and treating steel. The raw materials are 30-60% of zinc powder, 20-40% of 5083 magnesium aluminum alloy powder, 1-3% of ammonium chloride and the balance of aluminum oxide according to the weight percentage. Wherein 5083 the magnesium-containing aluminum alloy powder comprises the following components: 4.0 to 4.9 percent of Mg, 93 to 96 percent of Al, and the granularity of 100 to 200 meshes.

The present invention provides a method for steel treatment. And (3) carrying out oil removal and rust removal treatment on the metal matrix, and then carrying out zinc impregnation treatment in a vacuum environment, wherein the annealing temperature is 420-470 ℃ and the annealing time is 3-5 h. After cooling, the infiltration is carried out, and then passivation sealing treatment is carried out by using 5% nitric acid and chromate, so that the stability and corrosion resistance of the infiltration layer are improved, and the depth of the infiltration layer can reach 65 mu m.

According to the invention, Al and Mg elements of the magnesium-containing aluminum alloy 5083 alloy are added into the zincizing agent, so that the raw material cost is greatly reduced due to the lower price of the alloy. The penetrating agent has low cost, and the penetrating agent is applied to the steel materials, has simple process, and can prepare the penetrating layer without complex process production lines and professional equipment.

The zincating agent of the zinc-aluminum-magnesium powder is used for zincating a steel matrix to obtain a passivated surface texture map of a zinced layer, as shown in figure 1. Meanwhile, the cross section of the powder zincizing layer is shown in figure 2.

Drawings

FIG. 1 is a surface texture map of a infiltrated layer after passivation treatment in example 3 of the present invention.

FIG. 2 is a cross-sectional view of a powder zincized layer in example 3 of the present invention.

Detailed Description

Example 1

Step 1, weighing zinc powder according to the mass ratio: 30%, 5083 magnesium-containing aluminum alloy powder: 40 percent, 2 percent of ammonium chloride and the balance of alumina filler, wherein the mass percentage of the total percentage is 100 percent.

And 2, ball-milling the powder obtained in the step 1 for 1 hour by using a stellar ball mill, wherein the ball-milling parameter is 225r/min, and thus obtaining the zinc-aluminum-magnesium powder zincing agent.

And 3, polishing a Q235 steel plate with the size of 10 × 3mm on 200#, 400#, 600# gauze paper, washing with distilled water for 2-3 times, and performing oil and rust removal treatment on the ground sample for later use.

And 4, embedding the processed sample into a permeating agent, putting the sample into a crucible sealed by glue, heating the sample to 420 ℃ in a tube furnace by using a vacuum quartz tube sealing device, preserving heat for 4 hours, and cooling the sample to room temperature in air.

And 5, quickly washing the surface powder of the infiltrated sample, washing the sample with absolute ethyl alcohol, and drying the sample.

And 6, putting the sample cleaned in the step 5 into 5% dilute nitric acid, and then passivating in a passivation solution to obtain the silvery white passivation film.

The sample seeping layer is about 58 mu m, the sample seeping layer hardness is 270.56HV, and after the sample is subjected to neutral salt spray experiment test, the appearance time of rust spots is 250 h.

Example 2

Step 1, weighing zinc powder according to the mass ratio: 50%, 5083 magnesium-containing aluminum alloy powder: 20 percent of ammonium chloride, 2 percent of ammonium chloride and the balance of alumina filler, wherein the mass percentage of the total percentage is 100 percent.

And 4, embedding the processed sample into a permeating agent, putting the sample into a crucible sealed by glue, heating the sample to 450 ℃ in a tubular furnace by using a vacuum quartz tube sealing device, preserving heat for 4 hours, and cooling the sample to room temperature in air.

The sample seeping layer is about 50 mu m, the sample seeping layer hardness is 260.98HV, and after the sample is subjected to neutral salt spray experiment test, the appearance time of rust points is 245 h.

Example 3

Step 1, weighing zinc powder according to the mass ratio: 40%, 5083 magnesium-containing aluminum alloy powder: 30 percent of ammonium chloride, 2 percent of ammonium chloride and the balance of alumina filler, wherein the mass percentage of the total percentage is 100 percent.

And 4, embedding the processed sample into a permeating agent, putting the sample into a crucible sealed by glue, heating the sample to 460 ℃ by using a vacuum quartz tube sealing device in a tube furnace, preserving the heat for 4 hours, and cooling the sample to room temperature by air.

And 6, putting the sample cleaned in the step 5 into 5% dilute nitric acid, and then passivating in a passivation solution to obtain a silvery white passivation film, wherein the silvery white passivation film is shown in figure 1.

The sample seeping layer is about 65 μm, as shown in figure 2, the sample seeping layer hardness is 278.92HV, and the sample is tested by a neutral salt spray experiment, and then the appearance time of rust points is 260 h.

Claims

1. A method for preparing a zinc-aluminum-magnesium powder zincizing agent and treating steel is characterized in that the zinc-aluminum-magnesium powder zincizing agent comprises the following components in percentage by mass: 30-60% of zinc powder, 20-40% of 5083 magnesium aluminum alloy powder, 1-3% of ammonium chloride and the balance of alumina filler.

2. The zincating agent for zinc-aluminum-magnesium powder according to claim 1, wherein: the 5083 magnesium-containing aluminum alloy powder comprises the following components: mg content of 4.0-4.9%, Al content of 93-96% and granularity of 100-200 meshes.

3. The zincating agent for zinc aluminum magnesium powder and the method for steel processing according to claim 1 or 2, wherein: after the metal matrix is subjected to oil and rust removal treatment, the metal matrix is wrapped and embedded in a penetrating agent in a vacuum environment to be subjected to zinc and aluminum magnesium penetration treatment.

4. The zincating agent for zinc aluminum magnesium powder and the method for steel processing according to claim 1, 2 or 3, wherein: the annealing temperature is 420-470 ℃, and the time is 3-5 h.

5. The zincating agent for zinc aluminum magnesium powder and the method for steel processing according to claim 1 or 2 or 3 or 4, wherein: after the infiltration, passivation sealing treatment is carried out by using 5 percent nitric acid and chromate.

6. The zincating agent for zinc aluminum magnesium powder and the method for steel processing according to claim 1 or 2 or 3 or 4 or 5, wherein: the matrix is treated by the zincizing agent, the hardness of a carburized layer is 278.92HV, and the depth of the carburized layer can reach 65 mu m.