A rare earth high-speed railway aluminum alloy strip

Abstract

The present application discloses a rare earth high-speed railway aluminum alloy strip, which includes a strip body. The composition of the strip body is as follows: Fe 4-6wt%, Ce 1.1-1.3wt%, Y 0.7-0.9wt%, Mg 0.5-1wt%, Si 0.3-0.7wt%, Zr 0.1-0.3wt%, and the rest is aluminum and inevitable impurities. The surface of the strip body also includes a protective coating formed by first nitriding treatment and then anodic oxidation treatment on the surface of the strip body. Compared with the prior art, the rare earth high-speed railway aluminum alloy strip of the present application ensures good flexibility to meet the requirements of wrapping the cable core, and at the same time has excellent mechanical properties and high corrosion resistance, and is well adapted to the requirements of cable core winding protection.

Description

Technical Field

[0001] The present application relates to alloy strips for cable shielding, and in particular to a rare earth high-iron aluminum alloy strip Background Art

[0002] The alloy strip for cable shielding is a coating material wound around the outside of the cable core in the cable, used to prevent electromagnetic interference (EMI) and radio frequency interference (RFI), and at the same time provide physical protection and grounding functions

[0003] The alloy strip for cable shielding is required to have excellent tensile strength, flexibility and anti-corrosion performance, be able to continuously strip during winding, have flexibility during laying, and have a low corrosion rate under the influence of moisture during production, damaged sheath during laying operation or cable electroosmosis effect, so as to protect the cable core

[0004] In the development trend of the existing technology, aluminum alloy strips are gradually used to replace copper alloy strips to reduce the cost of cables. However, compared with copper alloy strips, aluminum alloy strips still have deficiencies in tensile strength, flexibility and anti-corrosion performance

[0005] In the current technology, an anodic oxidation treatment method is used to coat the surface of the aluminum alloy strip, so that the aluminum alloy strip has anti-corrosion performance not weaker than that of high-quality copper alloy strips. However, the tensile strength and flexibility of the aluminum alloy strip still have a gap with high-quality copper alloy strips. Therefore, how to improve the strength and corrosion resistance of the alloy strip for cable shielding at the same time has become one of the important research and development directions of aluminum alloy strips Summary of the Invention

[0006] In order to improve the strength and corrosion resistance of the alloy strip for cable shielding at the same time, a rare earth high-iron aluminum alloy strip is provided

[0007] The above-mentioned object of the present invention is achieved by the following technical solutions

[0008] A rare earth high-iron aluminum alloy strip, including a strip body, and the composition of the strip body is as follows

[0009] Fe 4-6wt%

[0010] Ce 1.1-1.3wt%;

[0011] Y 0.7-0.9wt%;

[0012] Mg 0.5-1wt%;

[0013] Si 0.3-0.7wt%;

[0014] Zr 0.1-0.3wt%;

[0015] The balance is aluminum and unavoidable impurities

[0016] The surface of the strip body further includes a protective coating formed by first nitriding the surface of the strip body and then performing anodic oxidation treatment.

[0017] By adopting the above technical solution, a new type of strengthening framework is formed between the aluminum matrix and high-content iron, breaking through the Fe content limit of traditional aluminum alloys. The Fe-Al solid solution forms a multi-scale strengthening network with the nano-scale Al-Fe-RE dispersion phase as the strength-increasing phase, realizing the synergistic improvement of the matrix strength and ductility.

[0018] On the other hand, the combined addition of cerium (1.2 wt%) and yttrium (0.8 wt%) produces a dual effect. By the surface activity effect, the grain boundary energy is reduced, the grains are refined to the sub-micron level, and Al3(RE,Fe) intermetallic compounds are preferentially formed with Fe, inhibiting the excessive formation of brittle Al3Fe phase, and improving the alloy substructure stability above 400 °C.

[0019] As a result, the mechanical properties of the rare earth high-iron aluminum alloy strip simultaneously reach an excellent level in terms of flexibility, ductility, and strength.

[0020] In addition, the addition of Mg, Si, and Zr elements. Si reacts with rare earths to form a RE-Si-Al composite phase with higher thermal stability. The Zr-Fe coupling causes Zr atoms to segregate at the Al-Fe phase interface, improving the coarsening resistance of the precipitation phase.

[0021] During the subsequent nitriding treatment of the rare earth high-iron aluminum alloy strip, it reduces the adverse changes in the alloy metallographic structure caused by heating, and ensures that the mechanical properties of the rare earth high-iron aluminum alloy strip do not decay when the nitriding treatment improves the corrosion resistance and wear resistance of the rare earth high-iron aluminum alloy strip.

[0022] Therefore, the rare earth high-iron aluminum alloy strip of this application has excellent mechanical properties and high corrosion resistance, and is well adapted to the winding protection requirements of cable cores.

[0023] Optionally: The nitriding treatment steps are as follows:

[0024] After the strip body is subjected to surface pretreatment, plasma nitriding is carried out in an arc ion plating furnace to obtain the strip body after surface nitriding treatment.

[0025] Optionally: The nitriding treatment process parameters are as follows: the temperature is 400 °C, the nitriding atmosphere is 50 sccm nitrogen and 250 sccm argon, the vacuum degree is 0.03 mbar, the initial substrate bias voltage is -30 V and then gradually adjusted to -180 V, the column arc current is set to 80 A, and the heat preservation treatment time is 8 min.

[0026] By adopting the above technical solution, the surface of the strip body can be nitrided quickly and efficiently, reducing the influence of the temperature rise during the nitriding process on the alloy properties of the strip body. While ensuring the strength and toughness of the strip body, a nitrided layer is effectively formed, improving the corrosion resistance and wear resistance of the surface of the rare earth high-speed aluminum alloy strip of the present application.

[0027] Optionally: The surface pretreatment of the strip includes cleaning, drying, and spraying a pretreatment solution, and the pretreatment solution is a mixed solution of ethanol and dichloromethane.

[0028] By adopting the above technical solution, ethanol can activate the free hydroxyl groups on the surface of the strip. The boiling point of dichloromethane is lower than that of ethanol, and it can volatilize prior to ethanol, replacing the atmosphere attached to the surface of the strip, preventing the free hydroxyl groups on the surface of the strip from oxidizing when activated by combining with oxygen in the air, ensuring that the free hydroxyl groups on the surface of the strip enter the nitriding treatment process in a highly active state, thereby making the nitriding more uniform and rapid, and further improving the corrosion resistance and wear resistance of the surface of the rare earth high-speed aluminum alloy strip of the present application.

[0029] Optionally: The mass ratio of ethanol to dichloromethane in the sprayed pretreatment solution is 10:(1.3 - 1.37).

[0030] By adopting the above technical solution, the amount of dichloromethane used is small and the effect of the pretreatment solution is good, reducing the requirements for production environmental conditions and waste gas treatment.

[0031] Optionally: The anodic oxidation solution is obtained by compounding sulfuric acid and citric acid.

[0032] By adopting the above technical solution, the passivation effect is good, the passivation film is more uniform and dense, and the corrosion resistance of the surface of the rare earth high-speed aluminum alloy strip is good.

[0033] Optionally: The anodic oxidation solution is obtained by compounding sulfuric acid, citric acid, and sodium citrate.

[0034] By adopting the above technical solution, the passivation effect is good, the passivation film is more uniform and dense, and the corrosion resistance of the surface of the rare earth high-speed aluminum alloy strip is good.

[0035] Optionally: The thickness of the anodic oxidation layer in the protective coating film is 0.35 - 0.38 μm.

[0036] By adopting the above technical solution, the mechanical properties of the rare earth high-speed aluminum alloy strip and the corrosion resistance of the strip surface both reach an excellent level.

[0037] In summary, the present application has at least the following beneficial effects:

[0038] Compared with the prior art, the rare earth high-speed railway aluminum alloy strip of the present application ensures good flexibility to meet the requirements of strip-coated cable cores, and at the same time has excellent mechanical properties and high corrosion resistance, well adapting to the requirements of cable core winding protection. Detailed implementation mode

[0039] Example 1

[0040] A rare earth high-speed railway aluminum alloy strip, which includes a strip body and a protective coating on the surface of the strip body.

[0041] The composition of the strip body is: Fe 5.2wt%, Ce 1.22wt%, Y 0.86wt%, Mg 0.73wt%, Si 0.65wt%, Zr 0.22wt%, and the rest is aluminum and inevitable impurities.

[0042] The strip body is made from aluminum ingots and aluminum alloy ingots containing other component elements through melting, alloying, billet casting, surface milling, rolling, and slitting. The thickness of the strip body is 0.15 ± 0.02 mm, and the width of the strip body depends on the slitting size in the slitting step, which can be 1 - 20 cm. Here, a strip body with a width of 8 cm is taken as an example.

[0043] The protective coating is obtained by first subjecting the strip body to nitriding treatment and then to anodic oxidation treatment.

[0044] The specific formation method of the protective coating is as follows:

[0045] Clean, dry, and spray a pretreatment solution on the surface of the strip body. The pretreatment solution is a mixture of ethanol and dichloromethane in a mass ratio of 10:1.35, and the spraying amount of the pretreatment solution is 8.4 g / m2;

[0046] After the pretreatment solution on the surface of the strip body has completely volatilized, send the strip body into an arc plasma plating furnace for nitriding. The temperature in the furnace is 400 °C, the vacuum degree in the furnace is 0.03 mbar, the nitriding atmosphere is 50 sccm of nitrogen and 250 sccm of argon, the initial substrate bias voltage is -30 V and then gradually adjusted to -180 V, the column arc current is set to 80 A, and the heat preservation treatment time is 8 min;

[0047] After the treatment, wait for the strip body to cool naturally to obtain a strip body with nitrided surface;

[0048] Put the strip body with nitrided surface into an anodic treatment solution and conduct anodic oxidation treatment by passing an electric current. The anodic treatment solution is obtained by mixing sulfuric acid, citric acid, sodium citrate, and water in a mass ratio of 10:3.4:1.5:90, the electric current passed is 12 A, and the anodic oxidation treatment time is 10 min;

[0049] Thus, a protective coating is formed on the surface of the strip body.

[0050] After detection, the thickness of the protective coating is 0.365 ± 0.015 μm.

[0051] Comparative Example 1

[0052] An aluminum alloy strip without a coating on its surface. The composition of the aluminum alloy strip is Fe 5.2 wt%, Ce 1.22 wt%, Y 0.86 wt%, Mg 0.73 wt%, Si 0.65 wt%, Zr 0.22 wt%, and the rest is aluminum and unavoidable impurities.

[0053] The aluminum alloy strip is made from aluminum ingots and aluminum alloy ingots containing other component elements through melting, alloying, continuous casting, surface milling, rolling, and slitting. The thickness of the strip body is 0.15 ± 0.02 mm, and the width of the strip body depends on the slitting size in the slitting step, which can be 1 - 20 cm. Here, a strip body with a width of 8 cm is taken as an example.

[0054] Comparative Example 2

[0055] An aluminum alloy strip without a coating on its surface. The composition of the aluminum alloy strip is Fe 0.1 wt%, Ce 1.22 wt%, Y 0.86 wt%, Mg 0.73 wt%, Si 0.65 wt%, Zr 0.22 wt%, and the rest is aluminum and unavoidable impurities.

[0056] The aluminum alloy strip is made from aluminum ingots and aluminum alloy ingots containing other component elements through melting, alloying, continuous casting, surface milling, rolling, and slitting. The thickness of the strip body is 0.15 ± 0.02 mm, and the width of the strip body depends on the slitting size in the slitting step, which can be 1 - 20 cm. Here, a strip body with a width of 8 cm is taken as an example.

[0057] Comparative Example 3

[0058] An aluminum alloy strip, which includes a strip body and a protective coating on the surface of the strip body.

[0059] The composition of the strip body is Fe 0.1 wt%, Ce 1.22 wt%, Y 0.86 wt%, Mg 0.73 wt%, Si 0.65 wt%, Zr 0.22 wt%, and the rest is aluminum and unavoidable impurities.

[0060] The aluminum alloy strip is made from aluminum ingots and aluminum alloy ingots containing other component elements through melting, alloying, continuous casting, surface milling, rolling, and slitting. The thickness of the strip body is 0.15 ± 0.02 mm, and the width of the strip body depends on the slitting size in the slitting step, which can be 1 - 20 cm. Here, a strip body with a width of 8 cm is taken as an example.

[0061] The protective coating is obtained by anodizing the strip body.

[0062] The specific formation method of the protective coating is as follows:

[0063] Clean and dry the surface of the strip body, immerse it in the anodic treatment solution, and apply an electric current to conduct anodizing treatment. The anodic treatment solution is obtained by mixing sulfuric acid, citric acid, sodium citrate, and water in a mass ratio of 10:3.4:1.5:90. The applied electric current is 12 A, and the anodizing treatment time is 10 min;

[0064] Thus, a protective coating is formed on the surface of the strip body.

[0065] After detection, the thickness of the protective coating is 0.365 ± 0.015 μm.

[0066] Comparative Example 4

[0067] An aluminum alloy strip, which includes a strip body and a protective coating on the surface of the strip body.

[0068] The composition of the strip body is Fe 5.2 wt%, Ce 1.22 wt%, Y 0.86 wt%, Mg 0.73 wt%, Si 0.65 wt%, Zr 0.22 wt%, and the rest is aluminum and inevitable impurities.

[0069] The aluminum alloy strip is made from aluminum ingots and aluminum alloy ingots containing other component elements through melting, alloying, casting billets, milling the surface, rolling, and slitting. The thickness of the strip body is 0.15 ± 0.02 mm, and the width of the strip body depends on the slitting size in the slitting step, which can be 1 - 20 cm. Here, a strip body with a width of 8 cm is taken as an example.

[0070] The protective coating is obtained by anodizing the strip body.

[0071] The specific formation method of the protective coating is as follows:

[0072] Clean and dry the surface of the strip body, immerse it in the anodic treatment solution, and apply an electric current to conduct anodizing treatment. The anodic treatment solution is obtained by mixing sulfuric acid, citric acid, sodium citrate, and water in a mass ratio of 10:3.4:1.5:90. The applied electric current is 12 A, and the anodizing treatment time is 10 min;

[0073] Thus, a protective coating is formed on the surface of the strip body.

[0074] After detection, the thickness of the protective coating is 0.365 ± 0.015 μm.

[0075] Comparative Example 5

[0076] An aluminum alloy strip, which is different from that in Example 1 in that the composition of the strip body is different. The composition of the strip body in Comparative Example 2 is Fe 5.2wt%, Mg 0.73wt%, Si 0.65wt%, Zr 0.22wt%, and the balance is aluminum and inevitable impurities.

[0077] Comparative Example 6

[0078] An aluminum alloy strip, which is different from that in Example 1 in that the composition of the strip body is different. The composition of the strip body in Comparative Example 3 is Fe 5.2wt%, Ce 1.22wt%, Y 0.86wt%, Mg 0.73wt%, Zr 0.22wt%, and the balance is aluminum and inevitable impurities.

[0079] Comparative Example 7

[0080] An aluminum alloy strip, which is different from that in Example 1 in that the composition of the strip body is different. The composition of the strip body in Comparative Example 5 is Fe 5.2wt%, Ce 1.22wt%, Y 0.86wt%, Mg 0.73wt%, Si 0.65wt%, and the balance is aluminum and inevitable impurities.

[0081] Comparative Example 8

[0082] An aluminum alloy strip, which is different from that in Example 1 in that the composition of the strip body is different. The composition of the strip body in Comparative Example 6 is Fe 5.2wt%, Ce 1.22wt%, Y 0.86wt%, Si 0.65wt%, Zr 0.22wt%, and the balance is aluminum and inevitable impurities.

[0083] Example 2

[0084] A rare earth high-iron aluminum alloy strip, which is different from that in Example 1 in that the specific formation method of the protective coating is as follows:

[0085] Clean and dry the surface of the strip body;

[0086] Send the treated strip body into an arc plasma plating furnace for nitriding. The temperature in the furnace is 400°C, the vacuum degree in the furnace is 0.03 mbar, the nitriding atmosphere is 50 sccm nitrogen and 250 sccm argon, the initial substrate bias voltage is -30 V and then gradually adjusted to -180 V, the column arc current is set to 80 A, and the heat preservation treatment time is 8 min;

[0087] After the treatment, wait for the strip body to cool naturally to obtain a strip body with a nitrided surface;

[0088] The strip body with surface nitriding is put into an anodizing solution and energized for anodizing treatment. The anodizing solution is obtained by mixing sulfuric acid, citric acid, sodium citrate, and water in a mass ratio of 10:3.4:1.5:90. The energized current is 12 A, and the anodizing treatment time is 10 min;

[0089] Thus, a protective coating is formed on the surface of the strip body.

[0090] After detection, the thickness of the protective coating is 0.365 ± 0.015 μm.

[0091] Example 3

[0092] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the nitriding atmosphere in the arc plasma plating furnace is 30 sccm nitrogen and 270 sccm argon.

[0093] Example 4

[0094] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the nitriding atmosphere in the arc plasma plating furnace is 80 sccm nitrogen and 220 sccm argon.

[0095] Example 5

[0096] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the heat preservation treatment time in the arc plasma plating furnace is 4 min.

[0097] Example 6

[0098] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the heat preservation treatment time in the arc plasma plating furnace is 10 min.

[0099] Example 7

[0100] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the pretreatment solution is a mixture of ethanol and dichloromethane in a mass ratio of 10:0.8.

[0101] Example 8

[0102] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the pretreatment solution is a mixture of ethanol and dichloromethane in a mass ratio of 10:1.3.

[0103] Example 9

[0104] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the pretreatment liquid is a mixture of ethanol and dichloromethane in a mass ratio of 10:1.37.

[0105] Example 10

[0106] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the pretreatment liquid is a mixture of ethanol and dichloromethane in a mass ratio of 10:1.6.

[0107] Example 11

[0108] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the anodizing liquid is obtained by mixing sulfuric acid, citric acid, and water in a mass ratio of 10:3.4:90.

[0109] Example 12

[0110] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the anodizing liquid is obtained by mixing sulfuric acid and water in a mass ratio of 10:90.

[0111] Example 13

[0112] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the anodizing time is 7 minutes, and after inspection, the thickness of the protective coating is 0.10 ± 0.02 μm.

[0113] Example 14

[0114] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that in the specific formation method of the protective coating, the anodizing time is 18 minutes, and after inspection, the thickness of the protective coating is 0.20 ± 0.02 μm.

[0115] Example 15

[0116] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that the composition of the strip body is Fe 4wt%, Ce 1.1wt%, Y 0.7wt%, Mg 0.5wt%, Si 0.3wt%, Zr 0.1wt%, and the rest is aluminum and inevitable impurities.

[0117] Example 16

[0118] A rare earth high-speed railway aluminum alloy strip, different from Example 1 in that the composition of the strip body is Fe 6wt%, Ce 1.3wt%; Y 0.9wt%; Mg 1wt%; Si 0.7wt%; Zr 0.3wt%, and the rest is aluminum and inevitable impurities;

[0119] The aluminum alloy strips obtained in Examples 1 to 16 and Comparative Examples 1 to 8 were tested.

[0120] Tensile strength: Tested according to "GB / T 228.1-2021 Metallic materials - Tensile testing - Part 1: Method of test at room temperature".

[0121] Vickers hardness: Tested according to "GB / T 4340.1-2024 Metallic materials - Vickers hardness testing - Part 1: Test method".

[0122] Corrosion resistance: Tested according to "GB / T 10125-2021 Corrosion tests in artificial atmospheres - Salt spray tests", with the test conditions set as an 8wt% NaCl solution, pH 7.0, ambient temperature 35°C, test time 108h, and the test results expressed as the corrosion rate.

[0123] The test results are shown in Table 1 below.

[0124] Table 1. Test results of Examples 1 to 16 and Comparative Examples 1 to 8

[0125]

[0126] Combined with the above table, the aluminum alloy strips of Comparative Example 1 and Comparative Example 2 were not treated with an additional protective coating. The Fe content in the aluminum alloy strip of Comparative Example 1 was significantly higher than that of Comparative Example 2. In the test results, the tensile strength of the aluminum alloy strip of Comparative Example 1 increased compared to that of Comparative Example 2. However, at the same time, the hardness of Comparative Example 1 also increased compared to that of Comparative Example 1, and the corrosion rate of Comparative Example 1 increased significantly compared to that of Comparative Example 2. Therefore, it can be seen that although an increase in the Fe content in the existing conventional aluminum alloy strips without a protective coating will improve the strength of the strip, it will significantly weaken the flexibility and corrosion resistance of the strip, which is disadvantageous in the field of cable core wrapping materials.

[0127] Comparing Comparative Example 2 and Comparative Example 3, it can be seen that Comparative Example 3 was anodized on the basis of Comparative Example 2. Their strengths and hardnesses were similar, while the corrosion resistance of Comparative Example 3 was significantly improved compared to that of Comparative Example 2, which is in line with the influence of anodizing treatment on the corrosion resistance of strips in this field.

[0128] Comparing Comparative Example 1 and Comparative Example 4, it can be seen that Comparative Example 4 was anodized on the basis of Comparative Example 1. Their strengths and hardnesses are similar, but the corrosion resistance of Comparative Example 4 has decreased compared to Comparative Example 1. After the applicant analyzed the anodic protective film obtained by anodizing, it was found that a large amount of hydrated complexes of iron hydroxides and oxides were mixed into the anodic protective film of Comparative Example 4, resulting in a decrease in the corrosion protection performance of the anodic protective film of Comparative Example 4. Therefore, for aluminum alloy strips, too high an Fe content has an adverse effect on the anti-corrosion effect brought by anodizing the strips.

[0129] Combining Example 1 and Comparative Examples 1-4, it can be seen that the tensile strength of the aluminum alloy strip in Example 1 of the present application is better than that of Comparative Examples 1-4. At the same time, the hardness of Example 1 is similar to that of Comparative Examples 1 and 4 with high Fe content among Comparative Examples 1-4, and the corrosion rate of Example 1 is significantly lower than that of Comparative Examples 1-4. Therefore, compared with the prior art, the rare earth high-iron aluminum alloy strip taking Example 1 as an example of the present application ensures good flexibility to meet the requirements of wrapping the cable core, and at the same time has excellent mechanical properties and high corrosion resistance, and is well adapted to the requirements of cable core winding protection.

[0130] Combining Example 1 and Comparative Examples 5-8 again, Example 1 and Comparative Examples 5-8 are all aluminum alloy strips with high Fe content.

[0131] In Example 1 of the present application, in addition to a high content of Fe, Ce, Y, Mg, Si, and Zr were added to the strip, and the strip was first nitrided and then anodized;

[0132] In Comparative Example 5, in addition to a high content of Fe, Mg, Si, and Zr were added to the strip, and the strip was first nitrided and then anodized;

[0133] In Comparative Example 6, in addition to a high content of Fe, Ce, Y, Mg, and Zr were added to the strip, and the strip was first nitrided and then anodized;

[0134] In Comparative Example 7, in addition to a high content of Fe, Ce, Y, Mg, and Si were added to the strip, and the strip was first nitrided and then anodized;

[0135] In Comparative Example 7, in addition to a high content of Fe, Ce, Y, Si, and Zr were added to the strip, and the strip was first nitrided and then anodized.

[0136] In the test results, the tensile strength of Example 1 is significantly greater than that of Comparative Example 5, the hardness of Example 1 is not higher than that of Comparative Example 5, and at the same time, the corrosion rate of Example 1 is significantly lower than that of Comparative Example 5;

[0137] The tensile strength of Example 1 is significantly greater than that of Comparative Example 6. The hardness of Example 1 is not higher than that of Comparative Example 6, and at the same time, the corrosion rate of Example 1 is lower than that of Comparative Example 6;

[0138] The tensile strength of Example 1 is significantly greater than that of Comparative Example 7. The hardness of Example 1 is not higher than that of Comparative Example 7, and at the same time, the corrosion rate of Example 1 is lower than that of Comparative Example 7;

[0139] The tensile strength of Example 1 is significantly greater than that of Comparative Example 7. The hardness of Example 1 is not higher than that of Comparative Example 7, and at the same time, the corrosion rate of Example 1 is lower than that of Comparative Example 7.

[0140] It can be seen from this that Example 1 of the present application can achieve good flexibility to meet the requirements of strip-coated cable cores compared with the prior art, and at the same time, it also has excellent mechanical properties and high corrosion resistance. The reasons are as follows:

[0141] 1. With a high Fe content and the addition of rare earth elements, a new strengthening framework is formed between the aluminum matrix and the high-content iron, breaking through the Fe content limit of traditional aluminum alloys. The Fe-Al solid solution serves as a strength-enhancing phase and forms a multi-scale strengthening network with the nano-scale Al-Fe-RE dispersion phase, realizing the synergistic improvement of the matrix strength and ductility.

[0142] 2. The strip surface is first nitrided and then anodically protected. By surface nitriding, the Fe alloy phase on the strip surface is changed, enhancing the corrosion resistance of the strip and eliminating the adverse effects of high Fe content on the corrosion resistance and anodic oxidation treatment of the strip.

[0143] 3. The rare earth elements selected are a combination of Ce and Y, and Mg, Si, and Zr are added. The combined addition of cerium (1.2 wt%) and yttrium (0.8 wt%) produces a dual effect. By surface activity, the grain boundary energy is reduced, the grains are refined to the sub-micron level, and it preferentially forms the Al3(RE,Fe) intermetallic compound with Fe, inhibiting the excessive formation of the brittle Al3Fe phase, and improving the stability of the alloy substructure above 400 °C; Si reacts with rare earths to form a more thermally stable RE-Si-Al composite phase, and the Zr-Fe coupling causes Zr atoms to segregate at the Al-Fe phase interface, enhancing the coarsening resistance of the precipitated phase. Mg coordinates and improves the miscibility between the components, optimizing the metallographic distribution. Therefore, during the nitriding process, the adverse changes in the alloy metallography caused by heating are reduced. When the nitriding treatment improves the corrosion resistance and wear resistance of the rare earth high-iron aluminum alloy strip, the mechanical properties of the rare earth high-iron aluminum alloy strip are ensured not to decay;

[0144] Only when the three are combined and coordinated can the performance of the aluminum alloy strip of the present application be achieved. None of the three can be missing. For example, Comparative Examples 6-8 lack the addition of Si, Zr, and Mg respectively, resulting in a decrease in the tensile strength after nitriding treatment compared with Example 1, and an increase in hardness, which is not conducive to the winding and coating requirements of cable zinc.

[0145] Combining Examples 1, 2, 7 - 10, it can be seen that the hardness of Examples 1, 8 - 10 is lower than that of Example 2, and the corrosion rates of Examples 1, 7 - 10 are lower than that of Example 2. Therefore, in this application, the pretreatment liquid prepared by compounding ethanol and dichloromethane can activate the free hydroxyl groups on the surface of the strip and reduce the oxidation of the strip, making the nitriding more uniform and rapid. The corrosion resistance and wear resistance of the surface of the rare earth high - iron aluminum alloy strip in this application are further improved.

[0146] In addition, the corrosion rates of Examples 1, 8, 9, 10 are lower than that of Example 7. When the mass ratio of ethanol to dichloromethane in the pretreatment liquid is 10:(1.3 - 1.37), the effect is better, and the amount of dichloromethane used is small, reducing the requirements for production environmental conditions and waste gas treatment.

[0147] Comparing Example 1 with Examples 3 - 6, it can be seen that the tensile strength of Example 1 is greater than that of Examples 3 - 4, and the corrosion rate of Example 1 is lower than that of Examples 3 - 4; the tensile strengths of Example 1 and Example 5 are similar, and the corrosion rate of Example 1 is lower than that of Example 5; the corrosion rates of Example 1 and Example 6 are similar, and the tensile strength of Example 6 is lower than that of Example 1. Therefore, in this application, the nitriding treatment parameters are controlled as follows: temperature is 400 °C, nitriding atmosphere is 50 sccm nitrogen, 250 sccm argon, vacuum degree is 0.03 mbar, the initial substrate bias voltage is - 30 V and then gradually adjusted to - 180 V, the column arc current is set to 80 A, and the holding treatment time is 8 min. The comprehensive performance of the obtained aluminum alloy strip is relatively excellent.

[0148] Combining Example 1 with Examples 11 - 12, it can be seen that the corrosion rate of Example 1 is lower than that of Example 11, and the corrosion rate of Example 11 is lower than that of Example 12. Therefore, in this application, when the anodic oxidation solution is a compound of sulfuric acid, citric acid, and sodium citrate or sulfuric acid and citric acid, the treatment effect is better.

[0149] Combining Example 1 with Examples 13 - 14, it can be seen that by adjusting the anodic oxidation treatment time, protective coatings with different thicknesses are obtained. The corrosion rates of Example 1 and Example 14 are lower than that of Example 13. Therefore, in this application, the thickness of the protective coating obtained by first nitriding treatment and then anodic oxidation treatment is 0.35 - 0.38 μm, and the protective performance is better, and the production time cost and energy consumption cost are lower.

[0150] In addition, there are other better solutions in the research process of adjusting the alloy composition of the strip body in this application. For example, in Examples 15 to 16, the tensile properties, hardness, and corrosion resistance of Examples 15 to 16 are similar to those of Example 1, and their comprehensive performance has significant progress compared with the prior art. The improvement effect of this application can be achieved as long as the composition of the strip body in this application is controlled within the following range: Fe 4 to 6 wt%, Ce 1.1 to 1.3 wt%, Y 0.7 to 0.9 wt%, Mg 0.5 to 1 wt%, Si 0.3 to 0.7 wt%, Zr 0.1 to 0.3 wt%, and the rest is aluminum and inevitable impurities.

[0151] This specific embodiment is only an interpretation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment that do not contribute creatively as needed, but as long as they are within the scope of protection required by the present invention, they are protected by the patent law.

Claims

1. A rare earth high iron aluminum alloy strip, characterized in that: It includes a strip body, and the strip body has the following components: Fe 4~6wt% Ce 1.1~1.3wt%; Y 0.7~0.9wt%; Mg 0.5~1wt%; Si 0.3~0.7wt%; Zr 0.1~0.3wt%; The rest is aluminum and unavoidable impurities; The surface of the strip body also includes a protective coating formed by first nitriding the surface of the strip body and then performing anodizing treatment; The nitriding treatment steps are as follows: After the strip body is subjected to surface pretreatment, plasma nitriding is performed in an arc ion plating furnace to obtain a strip body after surface nitriding treatment; The nitriding process parameters are as follows: temperature is 400°C, nitriding atmosphere is 50sccm nitrogen, 250sccm argon, vacuum is 0.03mbar, substrate initial bias is -30V and then gradually adjusted to -180V, column arc current is set to 80A, and heat preservation time is 8min; The surface pretreatment includes cleaning, drying, and spraying a pretreatment liquid. The pretreatment liquid is a mixture of ethanol and dichloromethane, and the mass ratio of ethanol to dichloromethane is 10:(1.3~1.37).

2. The rare earth high iron aluminum alloy strip according to claim 1, characterized in that: The anodizing solution is prepared by mixing sulfuric acid and citric acid.

3. The rare earth high iron aluminum alloy strip according to claim 1, characterized in that: The anodizing liquid is prepared by mixing sulfuric acid, citric acid and sodium citrate.

4. The rare earth high iron aluminum alloy strip according to claim 1, characterized in that: The thickness of the anodized layer in the protective coating is 0.35-0.38 μm.

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