WO2010012184A1

WO2010012184A1 - High potential magnesium alloy sacrificial anode and manufacturing method thereof

Info

Publication number: WO2010012184A1
Application number: PCT/CN2009/072564
Authority: WO
Inventors: 徐河; 赵言辉; 梁国军; 房中学; 黄银善
Original assignee: 维恩克（鹤壁）镁基材料有限公司
Priority date: 2008-07-29
Filing date: 2009-06-30
Publication date: 2010-02-04
Also published as: CN101638786A; CN101638786B

Abstract

Provided are a high potential Mg alloy sacrificial anode and a manufacturing method thereof, the high potential Mg alloy sacrificial anode has the following chemical composition percent by weight: Zn 0 - 0.4%, Al ≤ 0.01%, Si ≤ 0.02%, Mn ≤ 0.05%, Fe ≤ 0.03%, Ni ≤ 0.003%, Cu ≤ 0.005%, the remainder being Mg, and the open-circuit potential of the high potential Mg alloy sacrificial anode is above -1.80V, the current efficiency is above 60%. The manufacturing method of the high potential Mg alloy sacrificial anode is easy and inexpensive, and the electrical properties of the high potential Mg alloy sacrificial anode are superior to ASTM standard requirements.

Description

High-potential magnesium alloy sacrificial anode and preparation method thereof

[1] The present invention relates to a magnesium alloy sacrificial anode, and more particularly to a novel low cost high potential magnesium alloy sacrificial anode.

Background technique

[2] The corrosion of metallic materials is spread across all areas of the national economy. The direct and indirect economic losses caused by corrosion are enormous, and the impact of corrosion on the environment and ecological balance is also significant. Therefore, the issue of metal corrosion and protection has received widespread attention and has become an important research area in the material science.

[3] There are many ways to prevent metal corrosion. Electrochemical cathodic protection is one of the most important methods. The use of cathode protection is an important metal corrosion protection measure. When the metal is immersed in the electrolyte, the chemical reaction easily occurs. According to the electrochemical principle, electrochemical corrosion may occur due to differences in electrolyte composition, adhesion impurities, stress, and gas permeability around the metal. In the electrochemical corrosion process, the metal itself forms a number of galvanic cells, some of which act as cathodes and others act as anodes. In the anode region, metal particles enter the solution, electrons flow through the solution to the cathode, and positive ions entering the solution pass. The electrolyte flows from the anode to the cathode region, thus forming a current loop, which causes corrosion of the anode. The cathodic protection of the steel structure is to make the protected steel structure a cathode, and other metals with higher electronegativity, such as magnesium as an anode and form a loop. The electrons flow from the anode to the steel structure as a cathode, so that the steel cannot become positive ions entering the solution, so that the steel structure is protected. To achieve this, the sacrificial anode material must have a sufficiently negative and stable potential to ensure sufficient drive voltage.

[4] Because the sacrificial anode does not require an external power supply, does not interfere with adjacent metal facilities, and has good current dispersion capability.

It is easy to manage and maintain, so it is widely used in anti-corrosion engineering. Magnesium alloy sacrificial anode is one of the materials for electrochemical protection of metals. It is widely used in the cathodic protection of metal facilities such as soil, fresh water, sea water, water supply and drainage in urban construction, gas, natural gas, heating, oil pipelines, etc. It has anti-corrosion effect on metal and has broad application prospects. Compared with other sacrificial anodes, magnesium alloy sacrificial anodes have low density, large theoretical capacitance, negative potential, low polarizability, and driving voltage to steel. Large, suitable for the protection of metal parts with high resistivity and fresh water.

[5] Magnesium alloy sacrificial anodes are classified into two types: high potential and low potential. High-potential magnesium alloy sacrificial anode material is made by American Dow

Invented by Chemical, and the American Standard for Sacrificial Anodes of Magnesium Alloys ASTM 843-1993 (2003

) was also drafted by the company. Chinese standard GB/T

17731-2004 is the US standard for use. According to the American Standard Specification for Sacrificial Anodes of Magnesium Alloys, ASTM 843 - 199 3 (2003), the sacrificial anode composition of high-potential magnesium alloys is required to satisfy (wt% by weight) Mn 0.5-

1.3%, Al<0.01%, Fe<0.01%, Ni<0.001%, Cu<0.01%, Si<0.05%, the other individual impurity content does not exceed 0.05%, and the electrical properties are required to satisfy the open circuit potential greater than -1.7V. Current efficiency is greater than 50%. Manufacturers and suppliers around the world are currently using reference ASTM843-1993 (200

3) Standards established by the standards have certain requirements for Mn content. In addition, the current efficiency of the high-potential magnesium alloy sacrificial anodes currently prepared is generally about 50%.

However, the melting point of manganese metal is 1244 ° C much higher than the melting point of magnesium 648.9 ° C, so it is necessary to add manganese at a relatively high temperature. At high temperatures, the magnesium melt is more susceptible to oxidation, bringing in more oxides, which can severely reduce the potential and current efficiency of the high-potential magnesium alloy sacrificial anode. In addition, manganese chloride (MnC12) is formed, and manganese chloride is easy to absorb moisture, and water vapor is very dangerous to molten magnesium, and even has the possibility of explosion, and the content of nickel and iron in manganese chloride is high. , new impurities will be introduced during use. There is therefore a need for a new magnesium alloy sacrificial anode that does not add manganese or replaces manganese with other other low melting point metals to achieve the electrical properties specified by the current ASTM standard.

Disclosure of invention

technical problem

[7] The object of the present invention is to provide an improvement for the insufficiency of the high-potential magnesium-manganese alloy sacrificial anode to meet the magnesium alloy sacrificial anode standard ASTM 843-1993 (2003) and the necessity of adding 0.5-1.3% manganese. A low-cost high-potential magnesium alloy sacrificial anode which does not require the addition of manganese and replaces manganese with other low-melting-point metals and a preparation method thereof.

[8] The high-potential magnesium alloy sacrificial anode material of the present invention is only added by adding a low melting point Zn

To change the potential and electrical properties of magnesium alloys. The zinc-added high-potential magnesium alloy sacrificial anode material can be remarkable The electrochemical performance of the magnesium alloy is improved, and the current efficiency is higher than that of the magnesium alloy sacrificial anode standard ASTM 843-1993 (2003), and the manufacturing process is simple and the cost is relatively low.

Technical solution

One aspect of the present invention provides a high potential magnesium alloy sacrificial anode comprising a chemical composition having a mass percentage as follows: Zn

0-0.4% Al ≤ 0.01 Si ≤ 0.02 Μ η ≤ 0·05%, Fe ≤ 0.03%, Ni ≤ 0.003%, Cu < 0.005, and the rest is Mg.

Preferably, the high-potential magnesium alloy sacrificial anode according to the present invention has a mass percentage of chemical composition: Zn

0-0.4% Al ≤ 0.006 Si ≤ 0.0078 Μ η ≤ 0·015%, Fe ≤ 0.0018%, Ni ≤ 0.0003%, C u < 0.0015, and the balance is Mg.

Preferably, the high-potential magnesium alloy sacrificial anode according to the present invention has a Zn content of 0.02-0.1% by mass.

05%。 The high-potential magnesium alloy sacrificial anode according to the present invention, the Zn content by mass percentage of 0.05%.

Another aspect of the present invention provides a method for manufacturing a high-potential magnesium alloy sacrificial anode, comprising the steps of: taking a chemical composition mass percentage of Al ≤ 0.01%, Si ≤ 0.02 Mn ≤ 0.05 Fe ≤ 0.03%, Ni < 0.003%, Cu<0.005, the remaining magnesium ingot is baked and preheated; the preheated magnesium ingot is placed in a crucible, and smelted at 710 ° C to 730 ° C to become a melt; after smelting, Add zinc ingot to the melt at 690 ° C - 750 ° C, so that the mass percentage of zinc content is: 0 ≤ Zn

<0.4; After that, the melt is controlled to be refined at a temperature of 700 ° C to 740 ° C for 10-30 minutes after refining; after the refining is completed, the melt temperature is controlled at 700 ° C to 740 ° C, and the temperature is maintained. Allow to stand for 20-60 minutes; and cast the melt into a mold at a temperature of 700-740 ° C for solidification.

Preferably, the method for producing a high-potential magnesium alloy sacrificial anode according to the present invention, wherein the preheated magnesium ingot is placed in a crucible, and smelted at 720 ° C to be a melt.

Preferably, the melt is controlled to be refined at a temperature of 740 °C.

Preferably, the method for manufacturing a high-potential magnesium alloy sacrificial anode according to the present invention, wherein the mass fraction of the chemical composition of the magnesium ingot is: Al ≤ 0.006%, Si ≤ 0.0078 Mn ≤ 0.015%, Fe < 0.0018 °h, Ni ≤ 0.0003%, Cu < 0.0015, and the balance is Mg.

Beneficial effect

[17] The high-potential magnesium alloy sacrificial anode of the present invention has the advantages of low cost, simple manufacturing process, and has been changed for a long time, and it has been considered that it is necessary to add Mn element in order to prepare ASTM.

From the standpoint of a standard magnesium alloy sacrificial anode, the addition of zinc, which is less expensive and has a lower melting point, is added, and the current efficiency and potential of the zinc-added high-potential magnesium alloy sacrificial anode of the present invention exceeds the current ASTM standard. Has a broader application prospects.

DRAWINGS

[18] Figure 1 shows the current efficiency of a high-potential magnesium alloy sacrificial anode corresponding to different contents of manganese.

2 is a graph showing the current efficiency of a high-potential magnesium alloy sacrificial anode corresponding to different contents of zinc of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[20] First, the inventor of the present application prepared manganese content in accordance with the magnesium alloy sacrificial anode standard ASTM 843-1993 (2003) by adding manganese to a high-purity magnesium ingot produced by Wienke (Hebi) Magnesium-based Materials Co., Ltd. A high-potential magnesium alloy sacrificial anode sample was used to verify the electrical properties of a high-potential magnesium alloy sacrificial anode that meets this content standard.

[21] The raw material of the high-potential magnesium alloy sacrificial anode to which manganese is added is the above-mentioned high-purity magnesium ingot, and the chemical composition percentage thereof is: Al≤0.006%, Si≤0.0078%, Μη≤0·015%, Fe≤0.0018%, Ni<0.0003%, Cu<0.0015, the other content of other impurities is not more than 0.01%, and the balance is Mg. First, the mass percentage of Mn content is 0.1%, Al≤0.006%, Si≤0.0078%, Fe≤0.0018%, Ni<0.0003%, Cu<0.0015, the other content of other impurities is not more than 0.01%, and the balance is Mg. Magnesium alloy sacrificial anode sample.

[22] The specific preparation process of the manganese-added high-potential magnesium alloy sacrificial anode is as follows: After preheating the magnesium ingot, it is placed in a crucible and melted at 720 ° C; after the melting is completed, Manganese powder was added to the melt at 760 ° C to achieve a manganese content of 0.1%; then the melt was controlled to be refined at 740 ° C for 15 minutes; then it was allowed to stand at 720 ° C for 120 minutes. The melt is then cast into a mold (e.g., a metal mold) at this temperature for solidification molding. The prepared samples were sampled and tested for electrical properties. The test results are as follows: The circuit potential reaches -1.72V and the current efficiency is 52%, as shown in Figure 1.

[23] In addition, manganese content percentages of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, and 0.7 were also prepared. % high potential magnesium alloy sacrificial anode. The electrical properties of the prepared high-potential magnesium alloy sacrificial anodes were tested. The test results are shown in Figure 1. The current efficiency is about 50%, and the potentials are all -1.70V, which meets the requirements of the United States. Magnesium Alloy Sacrificial Anode Standard ASTM 843-1993 (2003).

[24] It can be seen that the high-potential magnesium alloy sacrificial anode material with manganese added satisfies the American magnesium alloy sacrificial anode standard ASTM 843-1993 (2003) in terms of composition and electrical properties, but its current efficiency is not significantly greater than the above. The value specified by the standard is 50%. Moreover, due to the high price of manganese, the cost of materials is increased. In addition, since the melting point of manganese is as high as 1244 ° C, it is necessary to carry out smelting at a relatively high temperature, and the temperature tends to fluctuate at a high temperature, and the stability is poor, so that it is difficult to control, and it is necessary to stand still for a long period of time in order to completely melt the manganese. , thus consuming a lot of energy.

[25] Therefore, in order to reduce the manufacturing cost of the magnesium alloy sacrificial anode, simplify the manufacturing process and reduce the energy consumption, we replaced the manganese with a lower melting point and cheaper zinc, and prepared a high-potential magnesium alloy sacrificial anode with zinc added.

[26] The mass percentages of the chemical components used in the present invention are: Al ≤ 0.01%, Si ≤ 0.02 Mn ≤ 0.05%, Fe ≤ 0.03 Ni ≤ 0.003 Cu < 0.005, and the rest are Mg ingots and Wienke (Hebi) The mass percentage of chemical components produced by Magnesium-based Materials Co., Ltd. is: Al ≤ 0.006%, Si ≤ 0.0078 Mn < 0. 015% Fe ≤ 0.0018 Ni ≤ 0.0003%, Cu ≤ 0.0015%, and the content of other impurities is not more than 0.01% by mass. A high-purity magnesium ingot with a balance of Mg was used as a raw material to prepare a high-potential magnesium alloy sacrificial anode having a zinc content of 0-0.4% by mass. The percentage by mass of chemical constituents is: Zn

0-0.4% Al ≤ 0.01 Si ≤ 0.02 Μ η ≤ 0 · 05%, Fe ≤ 0.03%, Ni ≤ 0.003%, Cu < 0.005 %, the remaining Mg high-potential magnesium alloy sacrificial anode, and the chemical composition mass percentage are: Zn

0-0.4% Al ≤ 0.006 Si ≤ 0.0078 Μ η ≤ 0 · 015%, Fe ≤ 0.0018%, Ni ≤ 0.0003%, C u ≤ 0.0015%, the balance of the high potential magnesium alloy sacrificial anode for electrical performance test, test The results are as follows: The high potential magnesium alloy sacrificial anodes of the above two components have a crotch potential greater than -1.7 V and a current efficiency greater than 50%, which satisfies the electrical properties specified in the magnesium alloy sacrificial anode standard ASTM 843-1993 (2003).

[27] The following is a description of the preparation of the present invention by taking a magnesium ingot having a mass percentage of raw materials of Al ≤ 0.006%, Si ≤ 0.0078%, Mn ≤ 0.015%, Fe < 0.0018%, Ni ≤ 0.0003 Cu ≤ 0.0015, and Mg as an example. The Zn content of the high-potential magnesium alloy sacrificial anode is 0.05%, Al ≤ 0.006%, Si ≤ 0.0078%, Mn ≤ 0.015%, Fe < 0.0018, Ni ≤ 0.0003 Cu ≤ 0.0015. [28] The same as the raw material of the above-mentioned manganese-added magnesium alloy sacrificial anode, the mass percentage of the chemical component used is: Al ≤ 0.006 Si ≤ 0.0078 Μ η ≤ 0·015%, Fe ≤ 0.0018%, Ni ≤ 0.0003%, Cu <0. 0015%, a high-purity magnesium ingot with a balance of Mg. First, the content of Zn is 0.05%, Al < 0.006%, Si ≤ 0.0078 Μ η ≤ 0·015%, Fe ≤ 0.0018%, Ni ≤ 0.0003%, and Cu < 0.0015.

A high-potential magnesium alloy sacrificial anode with a balance of Mg.

[29] The method for preparing a high-potential magnesium alloy sacrificial anode having a zinc content of 0.05% by mass is as follows: After preheating the magnesium ingot, it is placed in a crucible at 710 ° C - 730 (preferably 720 ° C) Melting. After the melting is completed, a zinc ingot is added to the melt at 690 ° C - 750 ° C (preferably 740 ° C) to achieve a zinc content of 0.05% by mass; then the melt is controlled at 700 ° C - 740 ° C ( It is preferably 740 ° C) for refining, refining for 10-30 minutes (preferably 15 minutes); then standing at 700-740 ° C (preferably 720 ° C) for 20-60 minutes (preferably 40 minutes) Then, the melt is cast into a mold at this temperature to solidify.

[30] As an example, the above method for preparing a high-potential magnesium alloy sacrificial anode having a zinc content of 0.05% by mass may be as follows: after baking and preheating the magnesium ingot, it is placed in a crucible at 720°. C is melted; then, the zinc ingot is added to the melt at a temperature of 740 ° C to have a mass percentage of 0.05%; then the melt is controlled to be refined at 740 ° C for 15 minutes; then it is allowed to stand at 720 ° C. The temperature was kept for 40 minutes; then the melt was cast into a mold at this temperature to solidify.

[31] As another example, the method for preparing the high-potential magnesium alloy sacrificial anode having the zinc content of 0.05% by mass may be as follows: after baking and preheating the magnesium ingot, putting it into the crucible, at 710 °C is melted; then the zinc ingot is added to the melt at a temperature of 690 ° C to make it a mass percentage of 0.0 5%; then the melt is controlled to be refined at 700 ° C for 30 minutes; then at 700 ° C The mixture was allowed to stand for 60 minutes; then the melt was cast into a mold at this temperature to solidify. In addition, the preparation method may also be: melting at 730 ° C; adding zinc ingot at a temperature of 740 ° C; refining at 740 ° C for 10 minutes, and standing at this temperature for 20 minutes, then melting the melt Cast into a mold for solidification.

[32] Samples were prepared and tested for electrical performance. The test results are as follows: The circuit potential reaches -1.80V, and the current efficiency is as high as 61.8% (as shown in Figure 2). It is clear from the test results that the electrical properties of the high-potential magnesium alloy sacrificial anode having a zinc content of 0.05% by mass are superior to those of the magnesium alloy sacrificial anode standard AST M843-1993 (2003), and the current efficiency thereof is compared. Electricity for sacrificial anodes of manganese-containing magnesium alloys Flow efficiency has increased by 20%.

[33] Since the high-potential magnesium alloy sacrificial anode is mainly used in large metal facilities such as soil, fresh water, seawater, water supply and drainage in urban construction, gas, natural gas, heating, oil pipelines, etc., the current efficiency is increased by 20%. The above-mentioned zinc-added high-potential magnesium alloy sacrificial anode material not only saves material cost, energy consumption and simplifies the process on the manufacturer side, but also has special characteristics in the user (construction unit) due to the high-potential magnesium alloy sacrificial anode application environment. It will save a lot of auxiliary materials, manpower and material resources, and the economic and social benefits it brings are enormous.

[34] In addition, the present invention also uses the above-mentioned high-purity magnesium ingot as a raw material, and the zinc content is respectively 0% by mass in the same manner as the above method for producing a high-potential magnesium alloy sacrificial anode having a zinc content of 0.05% by mass. High-potential magnesium alloy sacrificial anodes were not added with zinc), 0.02% 0.1%, 0.2% 0.4% 0.6% and 1.0%, and the electrical properties of these high-potential magnesium alloy sacrificial anodes with different zinc contents were tested. The test results show that the open circuit potential of these zinc-containing high-potential magnesium alloy sacrificial anodes reaches -1.70V. Figure 2 shows the test results of the current efficiencies of these zinc-containing high-potential magnesium alloy sacrificial anodes. As shown in Fig. 2, the high-potential magnesium alloy sacrificial anode with a zinc content of 0.4% or less has a current efficiency of more than 50%, which satisfies the requirements of the American magnesium alloy sacrificial anode standard ASTM 843-1993 (2003). In particular, the current efficiency of a high-potential magnesium alloy sacrificial anode with a zinc content of 0.02% to 0.1% is higher than 55%, which is significantly greater than the current efficiency of a high-potential magnesium alloy sacrificial anode to which manganese is added.

[35] In summary, the electrical properties of the high-potential magnesium alloy sacrificial anode prepared according to the present invention having a zinc content of 0.4% by mass or less satisfy the electrical properties specified by the American magnesium alloy sacrificial anode standard ASTM 843-1993 (2003). , has changed the long-standing high-potential magnesium alloy sacrificial anode that must be prepared by adding manganese to meet the electrical properties specified in the above-mentioned ASTM 843-1993 (2003). Further, the zinc-added high-potential magnesium alloy sacrificial anode of the present invention has a lower material cost, a simple manufacturing process, and lower energy consumption than a manganese-added high-potential magnesium alloy sacrificial anode.

While the invention has been described with respect to the exemplary embodiments, it is understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded

Embodiments of the invention Industrial applicability

[38]

Sequence table free content

Claims

Claim

[i] i.

A high-potential magnesium alloy sacrificial anode characterized in that the high-potential magnesium alloy sacrificial anode comprises a mass percentage of the following chemical composition: Zn

0-0.4% s Al ≤ 0.01 s Si ≤ 0.02 s Μ η ≤ 0·05%, Fe ≤ 0.03%, Ni ≤ 0.003%, Cu < 0.005%, and the rest is Mg.

[twenty two.

A high-potential magnesium alloy sacrificial anode according to claim 1, wherein the mass percentage of the chemical composition of the high-potential magnesium alloy sacrificial anode is: Zn

0-0.4% s Α1 ≤ 0·006%, Si ≤ 0.0078 s Μ η ≤ 0·015%, Fe ≤ 0.0018%, Ni < 0.0003%, Cu < 0.0015, and the balance is Mg.

[3] 3.

The high-potential magnesium alloy sacrificial anode according to claim 1 or 2, wherein the high-potential magnesium alloy sacrificial anode has a Zn content of 0.02-0.1% by mass.

[4] 4.

The high-potential magnesium alloy sacrificial anode according to claim 1 or 2, wherein the high-potential magnesium alloy sacrificial anode has a mass percentage of Zn content of 0.05%.

[5] 5. A method for manufacturing a high-potential magnesium alloy sacrificial anode, comprising the following steps:

[6] The mass percentage of chemical components is Α1≤0·01%, Si≤0.02 s Μη≤0·05%, Fe≤0.03%,

Ni ≤ 0.003%, Cu < 0.005, the remaining magnesium ingots for baking, preheating;

[7] baking the preheated magnesium ingot into a crucible, and melting it at 710 ° C - 730 ° C to make it into a melt;

[8] After smelting, a zinc ingot is added to the melt at 690 ° C - 750 ° C so that the mass percentage of zinc content is:

0<Zn <0.4 ;

[9] After that, the controlled melt is refined at a temperature of from 700 ° C to 740 ° C for 10-30 minutes during refining;

[10] After the refining is completed, the melt temperature is controlled at 700 ° C - 740 ° C, and the heat is allowed to stand for 20-60 minutes;

[11] The melt is cast into a mold at 700-740 ° C for solidification.

[12] 6.

A method of manufacturing a high-potential magnesium alloy sacrificial anode according to claim 5, characterized in that it is baked The preheated magnesium ingot was placed in a crucible and smelted at 720 ° C to make it a melt.

[13] The method for producing a high-potential magnesium alloy sacrificial anode according to claim 5 or 6, wherein

The melt was controlled to be refined at a temperature of 740 °C.

[14] 8.

The method for producing a high-potential magnesium alloy sacrificial anode according to claim 5 or 6, wherein the mass fraction of the chemical composition of the magnesium ingot is: Al ≤ 0.006%, Si ≤ 0.0078 Mn < 0.015 ° h, Fe ≤ 0.0018 Ni ≤ 0.0003%, Cu < 0.0015, and the balance is Mg.