Highly corrosion-resistant magnesium alloy, highly corrosion-resistant magnesium alloy casting material, and highly corrosion-resistant magnesium alloy die casting material

Abstract

The present invention provides: a highly corrosion-resistant magnesium alloy designed to exclude calcium added for high corrosion resistance; a highly corrosion-resistant magnesium alloy casting material; and a highly corrosion-resistant magnesium alloy die casting material. A magnesium alloy according to an embodiment of the present invention contains 6-9 wt% of aluminum (Al), 0.1-1.5 wt% of zinc (Zn), 0.05-0.4 wt% of manganese (Mn), 0.1-0.5 wt% of yttrium (Y), and 0.1 wt% to less than 2.0 wt% of mischmetal, with the remainder comprising magnesium (Mg) and inevitable impurities.

Description

High corrosion-resistant magnesium alloy, high corrosion-resistant magnesium alloy casting material, and high corrosion-resistant magnesium alloy die-casting material

[0001] The present invention relates to a magnesium alloy, and more particularly, to a high corrosion resistance magnesium alloy, a high corrosion resistance magnesium alloy cast material, and a high corrosion resistance magnesium alloy die-cast material designed to exclude calcium added for high corrosion resistance.

[0002] This invention was conducted as a result of research supported by the Ministry of Trade, Industry and Energy's 'Material Components Technology Development' [Project Name: Development of Magnesium Material Components Lighter by 25% or More Than Existing Components, Project Number: 20024843, Project Unique Number: 1415187745, Project Management (Specialist) Organization Name: Korea Institute of Industrial Technology Planning and Evaluation].

[0003] Magnesium alloys are lightweight alloys with high specific strength and can be applied to various casting and machining processes. They are applicable to almost all fields requiring lightweight materials, such as automotive, railway, and aircraft components, and electromagnetic components, and their application range is wide. However, magnesium alloys are electrochemically low and highly reactive metals, exhibiting a strong reactive reaction when in contact with oxygen or water. In addition, the ignition temperature of commercial alloys generally does not exceed 550℃, which can sometimes cause fires, and there are still limitations in terms of material stability and reliability. Therefore, the application range is still limited compared to its potential, and existing commercial magnesium alloys cannot be used in fields requiring safety such as railways or aerospace.

[0004] Most conventional high-corrosion, flame-retardant magnesium alloys contain calcium (Ca). Magnesium alloys containing calcium have high ignition temperatures, resulting in superior flame retardancy. When combined with other rare earth elements, they exhibit enhanced corrosion resistance. However, calcium presents the following serious problems in actual industrial parts manufacturing processes.

[0005] First, calcium can form calcium oxide, which can adhere as an inclusion on the inner wall of the melting furnace. Magnesium with added calcium element forms a stable calcium oxide (CaO) film on the liquid surface in the molten state, which suppresses the formation of highly reactive magnesium oxide (MgO). Although calcium oxide is less reactive than magnesium oxide, it exhibits ignition behavior similar to magnesium oxide once ignition begins. The highly adhesive calcium oxide film continuously adheres and deposits at the contact area between the melting furnace and the melt surface due to the periodically changing melt level during the casting process. As casting continues, serious ignition can frequently occur at the melt boundary on the inner wall of the melting furnace where calcium oxide and magnesium oxide are continuously deposited.

[0006] Calcium can also ignite in the ladle during the cold chamber die casting process. The cold chamber die casting process, which currently accounts for 95% of the domestic magnesium parts industry, uses a ladle to pour molten metal from a melting furnace into the sleeve of the die casting equipment. When calcium-doped molten metal is pumped into the ladle, a calcium oxide film forms around the ladle each time it is pumped. As the casting process progresses, this calcium oxide film gradually builds up on the ladle, and as the ladle temperature rises, ignition can occur.

[0007] Calcium can also cause hot cracking in products. While calcium is known to be effective in improving magnesium's flame retardancy, heat resistance, mechanical strength, and formability, it also causes hot cracking in cast parts, a long-standing problem. This is particularly true with the recent increase in complex-shaped die-cast parts, particularly electrical components, and the increasing demand for high precision, making hot cracking an even more serious problem.

[0008] Calcium also requires a dedicated flux. Flux is used for ignition prevention and refining during typical magnesium melting and recycling processes. When using commercial fluxes on calcium-doped magnesium alloys, the main component, magnesium chloride (MgCl2), is completely replaced by calcium chloride (CaCl2), consuming the calcium. Consequently, the recycling refining process becomes more complex and requires a dedicated flux.

[0009] The technical problem to be achieved by the technical idea of ​​the present invention is to provide a high corrosion resistance magnesium alloy, a high corrosion resistance magnesium alloy casting material, and a high corrosion resistance magnesium alloy die casting material designed to exclude calcium added for high corrosion resistance.

[0010] However, these tasks are exemplary and the scope of the present invention is not limited thereby.

[0011] A high corrosion resistance magnesium alloy according to the technical idea of ​​the present invention for achieving the above technical task comprises aluminum (Al) in the range of 1 wt% to 10 wt%; zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; misch metal in the range of 0.1 wt% to less than 2.0 wt%; and the remainder is magnesium (Mg) and unavoidable impurities.

[0012] In some embodiments of the present invention, the aluminum may be included in a range of 6 wt% to 9 wt%.

[0013] In some embodiments of the present invention, the micrometal may include lanthanum (La) and cerium (Ce).

[0014] In some embodiments of the present invention, the lanthanum may be in the range of 30 wt% to 70 wt% with respect to the total weight of the micro metal.

[0015] In some embodiments of the present invention, the cerium may be in the range of 30 wt% to 70 wt% with respect to the total weight of the micro metal.

[0016] In some embodiments of the present invention, the lanthanum and the cerium may have a lanthanum:cerium ratio in the range of 3:7 to 7:3 in weight %.

[0017] In some embodiments of the present invention, the micrometal may further include at least one of praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0018] In some embodiments of the present invention, the high corrosion resistance magnesium alloy may be configured to further include the yttrium and the micrometal based on at least one of AM50, AM60, AZ31, AZ61, AZ80, and AZ91.

[0019] In some embodiments of the present invention, the high corrosion resistance magnesium alloy may have a corrosion rate in the range of 0.2 mm / year to 0.9 mm / year.

[0020] A high corrosion-resistant magnesium alloy casting material according to the technical idea of ​​the present invention for achieving the above technical task comprises aluminum (Al) in the range of 1 wt% to 10 wt%; zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; micrometal in the range of 0.1 wt% to less than 2.0 wt%; and the remainder is magnesium (Mg) and unavoidable impurities.

[0021] A high corrosion resistance magnesium alloy die-casting material according to the technical idea of ​​the present invention for achieving the above technical task comprises aluminum (Al) in the range of 1 wt% to 10 wt%; zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; micrometal in the range of 0.1 wt% to less than 2.0 wt%; and the remainder is magnesium (Mg) and unavoidable impurities.

[0022] The technical idea of ​​the present invention is to provide a high corrosion resistance magnesium alloy. Conventional commercial magnesium alloys generally contain aluminum (Al) in the range of 1 wt% to 10 wt%, zinc (Zn) in the range of 0.1 wt% to 1.5 wt%, and manganese (Mn) in the range of 0.05 wt% to 0.4 wt%.

[0023] According to the present invention, to ensure corrosion resistance, a high-corrosion-resistant magnesium alloy was designed that excludes the conventionally included calcium and includes both yttrium and mischmetal. Compared to when yttrium and mischmetal are added as single elements, adding them together in an appropriate ratio ensures superior corrosion resistance.

[0024] The magnesium alloy according to the technical idea of ​​the present invention can provide excellent high corrosion resistance by including yttrium and micrometal together, and in particular, by having a corrosion rate of 1.0 mm / year or less, and a corrosion rate of 0.5 mm / year or less.

[0025] The effects of the present invention described above are illustrative, and the scope of the present invention is not limited by these effects.

[0026] Figures 1 to 4 are graphs showing the corrosion characteristics of a high-corrosion-resistant magnesium alloy containing 6 wt% aluminum according to an embodiment of the present invention.

[0027] FIGS. 5 and 6 are graphs showing corrosion characteristics of a high-corrosion-resistant magnesium alloy containing 9 wt% aluminum according to an embodiment of the present invention.

[0028] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Embodiments of the present invention are provided to more completely explain the technical idea of ​​the present invention to those skilled in the art. The following embodiments may be modified in various different forms, and the scope of the technical idea of ​​the present invention is not limited to the following embodiments. Rather, these embodiments are provided to more faithfully and completely convey the technical idea of ​​the present invention to those skilled in the art. Like reference numerals throughout this specification denote like elements. Furthermore, various elements and areas in the drawings are schematically drawn. Therefore, the technical idea of ​​the present invention is not limited by the relative sizes or intervals drawn in the attached drawings.

[0029] According to the technical idea of ​​the present invention, in order to overcome problems such as ignition and inclusion formation in the ingot casting process and die-casting parts manufacturing process in industrial sites due to calcium, which was essentially included in conventional high-corrosion-resistant flame-retardant magnesium alloys, and to secure high corrosion-resistance and flame-retardant properties at a level similar to or higher than that of conventional magnesium alloys, a magnesium alloy is provided which does not contain calcium but instead compositely adds yttrium and micrometal.

[0030] A high corrosion resistance magnesium alloy according to one embodiment of the present invention may include aluminum (Al) in the range of 1 wt% to 10 wt%; zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; misch metal in the range of 0.1 wt% to less than 2.0 wt%; and the remainder may include magnesium (Mg) and unavoidable impurities.

[0031] The above aluminum may be included in a range of 6 wt% to 9 wt%.

[0032] The above micro metal may be included in an amount ranging from 0.1 wt% to 1.5 wt%.

[0033] The above-mentioned micrometal may include lanthanum (La) and cerium (Ce). Based on the total weight of the micrometal, the lanthanum may be in the range of 30 wt% to 70 wt%. Based on the total weight of the micrometal, the cerium may be in the range of 30 wt% to 70 wt%. For example, in the micrometal, when the lanthanum is 70 wt%, the cerium may be 30 wt% or less. Additionally, in the micrometal, when the cerium is 70 wt%, the lanthanum may be 30 wt% or less.

[0034] The lanthanum and the cerium may have a lanthanum:cerium ratio ranging from 3:7 to 7:3 in weight percent. For example, the lanthanum and the cerium may have a lanthanum:cerium ratio of 1:1 in weight percent.

[0035] Additionally, the micrometal may include other rare earth materials, for example, at least one of praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0036] The above high corrosion resistance magnesium alloy can be excluded as it does not contain calcium.

[0037] The high corrosion resistance magnesium alloy may be formed based on a commercial alloy to further include the yttrium and the micrometal. For example, the high corrosion resistance magnesium alloy may be formed based on at least one of AM50, AM60, AZ31, AZ61, AZ80, and AZ91 to further include the yttrium and the micrometal. In the commercial alloy, the casting alloy may include, for example, 5 wt% to 9 wt% of aluminum.

[0038] The above-mentioned high corrosion resistance magnesium alloy may have a corrosion rate in the range of, for example, 0.2 mm / year to 0.9 mm / year, and in particular may have a corrosion rate of 0.5 mm / year or less.

[0039] A high corrosion-resistant magnesium alloy casting material according to one embodiment of the present invention is a casting material formed by performing a casting process using the high corrosion-resistant magnesium alloy described above. The high corrosion-resistant magnesium alloy casting material may include aluminum (Al) in the range of 1 wt% to 10 wt%; zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; micrometal in the range of 0.1 wt% to less than 2.0 wt%; and the remainder may include magnesium (Mg) and unavoidable impurities.

[0040] A high corrosion-resistant magnesium alloy die-casting material according to one embodiment of the present invention is a die-casting material formed by performing a die-casting process using the high corrosion-resistant magnesium alloy described above. The high corrosion-resistant magnesium alloy die-casting material may include aluminum (Al) in the range of 1 wt% to 10 wt%; zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; micrometal in the range of 0.1 wt% to less than 2.0 wt%; and the remainder may include magnesium (Mg) and unavoidable impurities.

[0041] The above-mentioned high corrosion-resistant magnesium alloy casting material and the above-mentioned high corrosion-resistant magnesium alloy die-casting material can have all the technical characteristics of the above-mentioned high corrosion-resistant magnesium alloy, and are omitted for the sake of brevity.

[0042] Experimental example

[0043] Below, experimental examples are described to aid understanding of the present invention. The following experimental examples are presented to aid understanding of the invention, and are not limited to the following experimental examples of the present invention.

[0044] A commercial magnesium alloy AM60 was prepared. The AM60 contained 6 wt% aluminum, 0.1 wt% zinc, 0.2 wt% manganese, and the remainder being magnesium and other unavoidable impurities.

[0045] Magnesium alloys were manufactured by adding yttrium alone, a fine metal alone, or yttrium and a fine metal together to commercial magnesium alloy AM60.

[0046] The above magnesium alloys were manufactured into plate-shaped ingots through gravity casting. In addition, the plate-shaped ingots were processed into specimens measuring 32 mm x 16 mm x 2 mm in accordance with the ASTM G31-72 immersion test standard.

[0047] Then, a solution containing 3.5 wt. NaCl was added (40 ml / mm 2 ) was immersed in water at pH 7 and 25℃ for 72 hours, and the weight loss was measured by removing corrosion products according to ASTM G1-90, and the corrosion rate was calculated from the weight loss.

[0048] Table 1 is a table showing the contents of yttrium and micrometal for experimental examples of a high corrosion resistance magnesium alloy containing 6 wt% aluminum according to one embodiment of the present invention.

[0049] Classification Yttrium Micrometal Lanthanum Cerium Experimental Example 10000 Experimental Example 20.1000 Experimental Example 30.3000 Experimental Example 40.5000 Experimental Example 51.0000 Experimental Example 600.10.050.05 Experimental Example 700.30.150.15 Experimental Example 800.50.250.25 Experimental Example 901.00.50.5 Experimental Example 100.10.10.050.05 Experimental Example 110.10.30.150.15 Experimental Example 120.10.50.2 50.25Experimental Example 130.11.00.50.5Experimental Example 140.11.50.750.75Experimental Example 150.12.01.01.0Experimental Example 160.30.10.050.05Experimental Example 170.30.30.150.15Experimental Example 180.30.50.250.25Experimental Example 190.31.00.50.5Experimental Example 200.31.50.750.75Experimental Example 210.32.01.01.0

[0050] Figures 1 to 4 are graphs showing the corrosion characteristics of a high-corrosion-resistant magnesium alloy containing 6 wt% aluminum according to an embodiment of the present invention.

[0051] Referring to Fig. 1, the corrosion rates for the cases of Experimental Examples 1 to 5, in which yttrium was added alone to the commercial magnesium alloy AM60, are shown. The commercial magnesium alloys have corrosion rates ranging from approximately 3 to 6 mm / year, although there are differences depending on the manufacturing process and alloy, and Experimental Example 1 had a corrosion rate of 5.13 mm / year.

[0052] Compared to Experimental Example 1 where yttrium was not added, when yttrium was added, the corrosion rate was reduced to less than 1.0 mm / year in all cases. When the amount of yttrium added increased from 0.1 wt% to 0.5 wt%, the corrosion rate tended to decrease. When the amount of yttrium added increased from 0.5 wt% to 1.0 wt%, the corrosion rate tended to increase again, and in the case of 1.0 wt% yttrium, it was slightly lower than in the case of 0.1 wt% yttrium. Therefore, it is analyzed that although the addition of yttrium alone tends to increase corrosion resistance because the corrosion rate decreases, there is a limit to securing high corrosion resistance.

[0053] When yttrium is added, the Al-Mn-Y phase is formed, and compared to the existing Al-Mn phase, the potential difference with the matrix is ​​relatively low, so the effect of galvanic corrosion is low, and corrosion resistance is increased due to the effect of removing iron impurities. However, it is analyzed that as the amount of yttrium added increases, the volume of the phase increases, and the effect of galvanic corrosion increases again, so the effect of increasing corrosion resistance is minimal. Therefore, it is preferable that yttrium is added in an amount of less than 1 wt%, or 0.5 wt% or less.

[0054] Referring to Fig. 2, Experimental Examples 6 to 9 show the corrosion rates when micrometal was added alone to commercial magnesium alloy AM60. Compared to Experimental Example 1 in which micrometal was not added, when micrometal was added, the corrosion rate decreased in all cases, but the degree of decrease was not as great as when yttrium was included alone. When the amount of micrometal added increased from 0.1 wt% to 0.5 wt%, the corrosion rate tended to decrease. When the amount of micrometal added increased from 0.5 wt% to 1.0 wt%, the corrosion rate tended to increase again, and the case of 1.0 wt% micrometal was lower than the case of 0.1 wt% micrometal. Therefore, it is analyzed that although the addition of micrometal alone tends to increase corrosion resistance because the corrosion rate decreases, there is a limit to securing high corrosion resistance.

[0055] Referring to Fig. 3, corresponding to Experimental Examples 10 to 15, the corrosion rates are shown when 0.1 wt% yttrium was added to commercial magnesium alloy AM60 and further micrometal was added. As micrometal was added, the corrosion rate decreased to less than 1.0 mm / year. When the amount of micrometal added increased from 0.1 wt% to 1.0 wt%, the corrosion rate tended to decrease. When the amount of micrometal added increased from 1.0 wt% to 2.0 wt%, the corrosion rate tended to increase again, and in particular, a large increase occurred at 2.0 wt%, showing 1.99 mm / year.

[0056] Therefore, when 0.1 wt% yttrium is added, it is preferable that the mischmetal be added in a range of, for example, 0.1 wt% to less than 2.0 wt%, for example, 0.1 wt% to 1.5 wt%. A preferred embodiment with the lowest corrosion rate is Experimental Example 13, which is analyzed for a case in which 0.1 wt% yttrium and 1.0 wt% mischmetal are added to a commercial magnesium alloy AM60 (Mg-6Al-0.1Zn-0.2Mn).

[0057] Referring to Fig. 4, corresponding to Experimental Examples 16 to 21, the corrosion rates are shown when 0.3 wt% yttrium was added to commercial magnesium alloy AM60 and also when micrometal was further added. As micrometal was added, the corrosion rate decreased to less than 0.7 mm / year. Compared to the case where 0.1 wt% yttrium was added in Fig. 3, the corrosion rate was further reduced overall. When the amount of micrometal added was 0.1 wt% to 0.5 wt%, the corrosion rates showed almost similar values, and at 1.0 wt% and 1.5 wt%, the corrosion rate decreased further, whereas at 2.0 wt%, it increased again, but showed a lower corrosion rate than Experimental Example 3 in which micrometal was not added.

[0058] Therefore, when 0.3 wt% yttrium is added, it is preferable that the mischmetal be added in a range of, for example, 0.1 wt% to less than 2.0 wt%, for example, 0.1 wt% to 1.5 wt%. A preferred embodiment with the lowest corrosion rate is Experimental Example 19, which is analyzed for a case in which 0.3 wt% yttrium and 1.0 wt% mischmetal are added to a commercial magnesium alloy AM60 (Mg-6Al-0.1Zn-0.2Mn).

[0059] The magnesium alloy according to the technical idea of ​​the present invention exhibits excellent high corrosion resistance, having a corrosion rate in the range of 0.2 mm / year to 0.9 mm / year, and in particular having a corrosion rate of 0.5 mm / year or less.

[0060] In addition, a commercial magnesium alloy AZ91 containing 9 wt% aluminum was prepared. The AZ91 contained 9 wt% aluminum, 1 wt% zinc, 0.3 wt% manganese, and the remainder being magnesium and other unavoidable impurities.

[0061] A magnesium alloy was prepared by adding yttrium and mischmetal to commercial magnesium alloy AZ91. In addition, the corrosion rate was calculated using the method described above.

[0062] Table 2 is a table showing the contents of yttrium and micrometal for experimental examples of a high corrosion resistance magnesium alloy containing 9 wt% aluminum according to one embodiment of the present invention.

[0063] Classification Yttrium Micrometal Lanthanum Cerium Experimental Example 220000 Experimental Example 230.10.10.050.05 Experimental Example 240.10.30.150.15 Experimental Example 250.10.50.250.25 Experimental Example 260.11.00.50.5 Experimental Example 270.30.10.050.05 Experimental Example 280.30.30.150.15 Experimental Example 290.30.50.250.25 Experimental Example 300.31.00.50.5

[0064] FIGS. 5 and 6 are graphs showing corrosion characteristics of a high-corrosion-resistant magnesium alloy containing 9 wt% aluminum according to an embodiment of the present invention.

[0065] Referring to Fig. 5, Experimental Examples 23 to 26 show the corrosion rates when 0.1 wt% yttrium and further micrometal were added to commercial magnesium alloy AZ91. The corrosion rate decreased as micrometal was added, and when the amount of micrometal added increased from 0.1 wt% to 1.0 wt%, the corrosion rate tended to decrease. A preferred example with the lowest corrosion rate is Experimental Example 26, which is analyzed to be a case where 0.1 wt% yttrium and 1.0 wt% micrometal were added to commercial magnesium alloy AZ91.

[0066] Referring to Fig. 6, Experimental Examples 27 to 30 show the corrosion rates when 0.3 wt% yttrium and further micrometal were added to commercial magnesium alloy AZ91. The corrosion rate decreased as micrometal was added, and when the amount of micrometal added increased from 0.1 wt% to 1.0 wt%, the corrosion rate tended to decrease. A preferred example with the lowest corrosion rate is Experimental Example 30, which is analyzed to be a case where 0.3 wt% yttrium and 1.0 wt% micrometal were added to commercial magnesium alloy AZ91.

[0067] It will be apparent to a person skilled in the art to which the technical idea of ​​the present invention pertains that the technical idea of ​​the present invention described above is not limited to the above-described embodiments and the attached drawings, and that various substitutions, modifications, and changes are possible within a scope that does not depart from the technical idea of ​​the present invention.

[0068] According to the technical idea of ​​the present invention, magnesium alloy is the lightest alloy with high specific strength, and can be applied to various casting and processing processes. It can be applied to almost all fields requiring lightweighting, such as automobile, railway, aviation parts, and electromagnetic parts, and has a wide range of applications.

Claims

Aluminum (Al) in the range of 1.1 wt% to 10 wt%; Zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; Manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; Yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; Misch metal in the range of 0.1 wt% to less than 2.0 wt%; and The remainder contains magnesium (Mg) and unavoidable impurities. High corrosion resistance magnesium alloy.

2. In paragraph 1, The above aluminum is included in a range of 6 wt% to 9 wt%, High corrosion resistance magnesium alloy.

3. In paragraph 1, The above micro metals are, Containing lanthanum (La) and cerium (Ce), High corrosion resistance magnesium alloy.

4. In paragraph 3, With respect to the total weight of the above micro metal, the lanthanum is in the range of 30 wt% to 70 wt%, High corrosion resistance magnesium alloy.

5. In paragraph 3, With respect to the total weight of the above micro metal, the cerium is in the range of 30 wt% to 70 wt%, High corrosion resistance magnesium alloy.

6. In paragraph 3, The above lanthanum and the above cerium have a lanthanum:cerium ratio in the range of 3:7 to 7:3 in weight %. High corrosion resistance magnesium alloy.

7. In paragraph 3, The above micro metals are, Further comprising at least one of praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). High corrosion resistance magnesium alloy.

8. In paragraph 1, The above high corrosion resistance magnesium alloy is, further comprising yttrium and the micrometal based on at least one of AM50, AM60, AZ31, AZ61, AZ80, and AZ91; High corrosion resistance magnesium alloy.

9. In paragraph 1, The above high corrosion resistance magnesium alloy is, Having a corrosion rate in the range of 0.2 mm / year to 0.9 mm / year, High corrosion resistance magnesium alloy. Aluminum (Al) in the range of 10.1 wt% to 10 wt%; Zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; Manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; Yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; Micro metals in the range of 0.1 wt% to less than 2.0 wt%; and The remainder contains magnesium (Mg) and unavoidable impurities. High corrosion resistance magnesium alloy casting material. Aluminum (Al) in the range of 11.1 wt% to 10 wt%; Zinc (Zn) in the range of 0.1 wt% to 1.5 wt%; Manganese (Mn) in the range of 0.05 wt% to 0.4 wt%; Yttrium (Y) in the range of 0.1 wt% to 0.5 wt%; Micro metals in the range of 0.1 wt% to less than 2.0 wt%; and The remainder contains magnesium (Mg) and unavoidable impurities. High corrosion resistance magnesium alloy die casting material.

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