KR20230062060A - Electrode drum used in a electrolytic process for producing copper foil and method for manufacturing the same - Google Patents

Abstract

An electrolytic electrode drum for manufacturing copper foil and a manufacturing method thereof are provided. An electrolytic electrode drum for producing copper foil includes i) a cylindrical rotating body, and ii) a plate material attached to the surface of the cylindrical rotating body. The sheet material contains 0.15wt% to 0.5wt% Fe, the remainder Ti and other impurities.

Description

Electrolytic electrode drum for manufacturing copper foil and manufacturing method thereof

The present invention relates to an electrolytic electrode drum for manufacturing copper foil and a manufacturing method thereof. More specifically, it relates to an electrolytic electrode drum for manufacturing copper foil using a Ti-Fe alloy and a manufacturing method thereof.

Demand for lithium secondary batteries is rapidly increasing due to the spread of portable devices such as mobile phones and laptops and electric vehicles. Electrolytic copper foil is mainly used as a material for an anode current collector of a lithium secondary battery. Electrolytic copper foil is manufactured through a copper foil manufacturing process by an electroplating method.

The electrolytic copper foil is manufactured by being attached to a drum-type negative electrode material that rotates opposite to the positive electrode material immersed in an electrolytic bath for mass production. That is, when an electrolytic solution containing metal ions is supplied to the electrolytic cell, an electrolytic copper foil having a target thickness is deposited on the surface of the drum-shaped negative electrode material by an electrolytic reaction. Then, the electrodeposited copper foil is peeled off from the surface of the drum-shaped negative electrode material.

Korean Registered Patent No. 2,260,510

It is intended to provide an electrolytic electrode drum for manufacturing copper foil having an average grain size of 30 μm or less while maintaining excellent corrosion resistance. In addition, it is intended to provide a manufacturing method of the above-described electrolytic electrode drum for manufacturing copper foil.

An electrolytic electrode drum for manufacturing copper foil according to an embodiment of the present invention includes i) a cylindrical rotating body, and ii) a plate material attached to the surface of the cylindrical rotating body. The sheet material contains 0.15wt% to 0.5wt% Fe, the remainder Ti and other impurities.

The amount of the β phase included in the plate may be 0.1wt% to 1.9wt%. The average grain diameter of the crystals of the plate material may be 30 μm or less. More preferably, the average grain diameter of the crystals of the plate material may be 10 μm to 30 μm. Alternatively, the average grain diameter of the crystals of the plate material may be 5.3 μm to 15.0 μm.

A method of manufacturing an electrolytic electrode drum for manufacturing copper foil according to an embodiment of the present invention includes i) providing a cylindrical core, and ii) providing a plate material on the surface of the cylindrical core. The step of providing a plate material is i) providing an ingot, ii) melting the ingot multiple times at 1700°C to 1800°C, iii) 900°C in a vacuum atmosphere of 10 ^-6 torr to 10 ^-4 torr. to 1100 ° C. for 5 to 15 hours of homogenization heat treatment, iv) preparing a rolled material by hot rolling the ingot at a rolling reduction of 70% to 90% at 600 ° C. to 800 ° C., and v) rolling material recrystallization by annealing at 650° C. to 750° C. for 30 minutes to 90 minutes. The sheet material contains 0.15wt% to 0.5wt% Fe, the remainder Ti and other impurities.

In the step of recrystallizing the rolled material, the rolled material may be annealed at 650°C to 750°C. The amount of the β-Ti phase included in the plate material is 0.1wt% to 1.9wt%, and the β-Ti phase may be located at the grain boundary of the plate material.

It is possible to manufacture a Ti-Fe alloy having an average grain size of 30 μm or less while maintaining excellent corrosion resistance required for an electrolytic electrode drum for manufacturing copper foil. Therefore, the yield of the copper foil can be greatly improved by suppressing the formation of Ti hydride generated on the surface of the electrode drum during copper foil manufacturing.

1 is a schematic diagram of a copper foil manufacturing apparatus including an electrolytic electrode drum according to an embodiment of the present invention.
FIG. 2 is a schematic conceptual diagram showing corrosion behavior of the surface of the electrolytic electrode drum of FIG. 1 .
3 is a schematic state diagram of a Ti-Fe alloy included in the electrolytic electrode drum of FIG. 1;
4 is a schematic manufacturing process diagram of a Ti-Fe alloy plate included in the electrolytic electrode drum of FIG. 1;
5 to 12 are graphs or tissue photographs showing experimental results according to experimental examples of the present invention.

The terminology used herein is intended only to refer to specific embodiments and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. As used herein, the meaning of "comprising" specifies specific characteristics, regions, integers, steps, operations, elements, and/or components, and other specific characteristics, regions, integers, steps, operations, elements, elements, and/or groups. does not exclude the presence or addition of

Although not defined differently, all terms including technical terms and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms defined in commonly used dictionaries are additionally interpreted as having meanings consistent with related technical literature and currently disclosed content, and are not interpreted in ideal or very formal meanings unless defined.

Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail so that those skilled in the art can easily practice it. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

1 schematically shows a copper foil manufacturing apparatus 100 including an electrolytic electrode drum 10 according to an embodiment of the present invention. The structure of the copper foil manufacturing apparatus 100 of FIG. 1 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the copper foil manufacturing apparatus 100 can be modified in other forms as well.

As shown in FIG. 1, the copper foil manufacturing apparatus 100 includes an electrolytic electrode drum 10 as a negative electrode material, a positive electrode material 20, an electrolytic bath 30, transfer rolls 40, and a winding roll 50. . In addition, the copper foil manufacturing apparatus 100 may further include other parts.

An aqueous solution of sulfuric acid (S) is accommodated in the electrolytic cell 30, and although not shown in FIG. 1, the electrolytic electrode drum 10 and the cathode material 20 are electrically connected to a power source, respectively. Therefore, when current is applied to the electrolytic electrode drum 10 and the cathode material 20, the sulfuric acid aqueous solution (S) is electrolyzed, and copper ions in the sulfuric acid aqueous solution (S) are reduced, and copper foil is formed on the surface of the electrolytic electrode drum (10). do. While the electrolytic electrode drum 10 rotates in the direction of the arrow, the copper foil is taken out of the electrolytic cell 30, transported by the transfer rolls 40, and then wound around the take-up roll 50.

To this end, the electrolytic electrode drum 10 includes a plate member 101, a cylindrical rotating body 103, and a rotating shaft 105. In addition, the electrolytic electrode drum 10 may further include other parts as needed. Meanwhile, although the rotating shaft 105 is shown as being separate in FIG. 1 , it may be omitted and the cylindrical rotating body 103 itself may serve as a rotating shaft and rotate.

The plate material 101 may be made of a ring-shaped member or a curved member. When the plate material 101 is provided as a ring-shaped member, it is fitted and fixed to the outer circumference of the cylindrical rotating body 103. A plurality of curved members are integrally attached to the surface of the cylindrical rotating body 103 through fitting or welding.

The plate material 101 is made of a Ti-Fe alloy. The Ti-Fe alloy contains 0.15wt% to 0.5wt% Fe, the remainder Ti and other impurities. Since the plate material 101 is immersed in the sulfuric acid solution (S), it must have corrosion resistance to the sulfuric acid solution (S). In one embodiment of the present invention, corrosion resistance is secured by using a Ti-Fe alloy for the electrolytic electrode drum 10.

Titanium has excellent corrosion resistance. Therefore, it is suitable for use in corrosive environments such as seawater or harmful gases. However, pure titanium will corrode when exposed to hot chloride solutions or low pH, non-oxidizing acidic solutions. In particular, when manufacturing copper foil, a non-oxidizing acidic solution is used, and titanium hydride is formed on the surface of the electrode drum during copper foil manufacturing, causing defects in the copper foil. Therefore, in order to use titanium as a material for an electrolytic electrode drum, a method of suppressing the generation of titanium hydride while maintaining corrosion resistance is required.

In one embodiment of the present invention, in order to solve this problem, titanium hydride is suppressed by using Fe as a crystal grain refinement element while minimizing corrosion resistance degradation by controlling the Fe content generally contained in a small amount in titanium. That is, by using Fe as a grain refinement element to refine the grain boundary, the grain boundary is greatly increased. As a result, the grain boundary sufficiently functions as a path for diffusion of hydrogen generated during the copper foil lamination process into the titanium matrix. Therefore, it is possible to suppress the formation of titanium hydride on the surface of the electrolytic electrode drum.

The titanium alloy contains 0.03wt% to 0.5wt% Fe, the remainder Ti and other impurities. When the amount of iron is too large, corrosion resistance is adversely affected in terms of Ti-β phase stabilization or TiFe intermetallic compound formation. In addition, when the amount of iron is too small, the titanium alloy becomes the same as pure titanium and corrosion resistance is maintained, but it is difficult to control the grain size to a desired level. Therefore, the amount of Fe is adjusted within the above range. Preferably, the amount of Fe may be 0.15wt% to 0.5wt%. In this case, a small amount of the Ti-β phase is present, so that the crystal grains can be refined while maintaining corrosion resistance.

On the other hand, Fe is added to titanium to refine the crystal grains of the titanium alloy. A small amount of Fe is added to titanium to form a β-Ti phase at the grain boundary. The β-Ti phase suppresses grain growth during recrystallization and finally refines grains.

When Fe is added, the corrosion resistance of the titanium alloy may be slightly deteriorated. Therefore, the content of Fe may be controlled to 0.15wt% to 0.5wt% in order to minimize corrosion resistance deterioration. In this case, although a β-Ti phase or a Ti-Fe intermetallic compound is formed and deteriorates corrosion resistance, corrosion resistance similar to that of pure titanium is secured by minimizing the amount of the β-Ti phase or Ti-Fe intermetallic compound. This will be described in more detail with reference to FIG. 2 .

FIG. 2 schematically shows the corrosion behavior of the surface of the electrolytic electrode drum of FIG. 1 . The corrosion behavior of the surface of the electrolytic electrode drum in FIG. 2 is only for exemplifying the present invention, and the present invention is not limited thereto. Therefore, it can be explained differently.

As shown in FIG. 2, the process of dissolving TiO ₂ on the surface of the electrode drum is conceptually sequentially shown. The Ti-Fe alloy includes a TiO ₂ layer formed over a Ti substrate. That is, the Ti substrate is generally an electrode drum, and the surface of the electrode used is oxidized to form a TiO ₂ layer. However, when the electrode drum is exposed to a high-concentration sulfuric acid solution, the TiO ₂ layer is melted or hydrated to form porous TiOOH, and ultimately the TiO ₂ layer providing corrosion resistance disappears. In particular, when a β-Ti phase is present, the tendency is more rapid and corrosion resistance is lowered. As a result, it is necessary to suppress or minimize the formation of the β-Ti phase in order to maintain the corrosion resistance of pure titanium.

Figure 3 shows the phase of the Ti-Fe alloy according to the addition of Fe when calculated thermodynamically. Thermodynamically, when Fe is added up to 0.5 wt%, only TiFe precipitates are formed and β-Ti phase is not formed. However, as shown in FIG. 5, in an actual product, a β-Ti phase is formed instead of TiFe precipitates. Therefore, in order to control the corrosion resistance of actual titanium alloy products, it is necessary to consider the β-Ti phase.

Figure 4 schematically shows a manufacturing process of the Ti-Fe alloy plate included in the electrode drum of Figure 1. The crystal structure of the Ti-Fe alloy indicated by the dotted circle at each stage of the graph of FIG. 4 is schematically shown below. The manufacturing process of the Ti-Fe alloy sheet of FIG. 4 is only for exemplifying the present invention, and the present invention is not limited thereto. Therefore, the manufacturing process of the Ti-Fe alloy plate can be modified in other forms.

As shown in Figure 4, the manufacturing process of the Ti-Fe alloy sheet includes the steps of vacuum arc melting (S10), homogenization treatment (S20), hot rolling (S30) and recrystallization (S40). In addition, the manufacturing process of the Ti-Fe alloy plate may further include other steps as needed.

In order to manufacture the electrolytic electrode drum 10 for manufacturing copper foil of FIG. 1, a cylindrical core is provided and a Ti-Fe alloy plate is provided on the surface thereof. Ti-Fe alloy sheet is made by first providing an ingot. In the ingot, there is artificially added Fe, not an impurity. For example, an ingot is prepared by adding a small amount of iron to a titanium sponge and melting it. Since Fe acts as a grain refinement component, crystal grains are refined as shown below in FIG. 4 according to the progress of the process.

First, in the vacuum arc melting (S10) step, the ingot is melted multiple times at 1700 °C to 1800 °C. That is, the ingot is remelted in a vacuum arc melting furnace. When the melting temperature of the ingot is too low, it is difficult to liquefy the ingot. In addition, when the melting temperature of the ingot is too high, a lot of energy is consumed. Therefore, the heating temperature of the ingot is maintained within the aforementioned range.

Next, in step S20, homogenization heat treatment is performed on the ingot cooled to room temperature. That is, the ingot is subjected to homogenization heat treatment at 900°C to 1100°C for 5 hours to 15 hours in a vacuum atmosphere of 10 ^-6 torr to 10 ^-4 torr. If the homogenization heat treatment temperature is too low, homogenization of the ingot components may be difficult. In addition, when the homogenization heat treatment temperature is too high, energy consumption is large. Therefore, the ingot is homogenized and heat treated in the above heat treatment temperature range. In addition, the homogenization heat treatment time is also maintained for the same reason as described above.

In step S30, a rolled material is manufactured by hot rolling the ingot cooled to room temperature. The ingot may be hot rolled at 600°C to 800°C with a reduction of 70% to 90%. If the hot rolling temperature is too low, cracks may form in the ingot. Also, when the hot rolling temperature is too high, energy consumption is high. Therefore, the ingot is rolled in the aforementioned hot rolling temperature range. Also, the ingot may be hot rolled with a reduction ratio of 70% to 90%. When the reduction ratio is too small, it is difficult to bend the sheet material to be produced. That is, since it must be used for the electrolytic electrode drum, the plate material must have some elasticity and be easy to bend. In addition, when the reduction ratio is too large, the energy consumption required for hot rolling is large. Therefore, the reduction ratio of the ingot is adjusted within the above range.

In step (S40), the rolled material cooled to room temperature is recrystallized by annealing at 650° C. to 750° C. for 30 to 90 minutes. More preferably, the rolling material may be annealed at a rather high temperature of 700° C. to 750° C. for crystal grain refinement. If the annealing time is too short, fatigue recovery of crystals included in the rolling material is difficult. Also, if the annealing time is too long, the crystals may be coarsened. Therefore, the annealing time is adjusted within the above range. The annealing temperature is adjusted as described above for the same reason.

The Ti-Fe alloy sheet produced by the above method may include 0.1wt% to 1.9wt% of the β-Ti phase. If the amount of the β-Ti phase is too large, the corrosion resistance of the Fe-Ti alloy sheet may deteriorate. Also, since the amount of Fe added is limited, the amount of the β-Ti phase cannot be designed to be too large. Therefore, the amount of the β-Ti phase is adjusted within the above range. On the other hand, the average grain size of the crystals of the Ti-Fe alloy sheet material is 30 μm or less. More preferably, the average grain diameter of the crystals of the Ti-Fe alloy plate may be 10 μm to 30 μm. Alternatively, the average grain diameter of the crystals of the Ti-Fe alloy plate may be 5.3 μm to 15.0 μm. If the average particle diameter of the crystal is too small, it is difficult to secure the necessary elasticity because it must be bent and used for the electrolytic electrode drum. Also, when the average grain size of the crystals is too large, the titanium hydride suppression of the Ti-Fe alloy sheet material may deteriorate. Therefore, the average grain size of the crystals is adjusted within the above range. Meanwhile, not only the β-Ti phase but also the TiFe intermetallic compound are present in a small amount in the grain boundary, so grain growth may be suppressed during recrystallization.

Hereinafter, the present invention will be described in more detail through experimental examples. These experimental examples are only for exemplifying the present invention, and the present invention is not limited thereto.

Experimental example

An ingot made of Ti-Fe alloy was remelted 5 times by vacuum arc melting to obtain a homogeneous composition. After re-melting, the cooled ingot was subjected to homogenization heat treatment at 1,000° C. for 10 hours in a high vacuum atmosphere of 10 ^-5 torr. Then, the cooled ingot was hot-rolled at 800° C. at a reduction ratio of 80% to manufacture a plate material having a thickness of 1.6 mm. Then, the sheet material was annealed for 60 minutes to sufficiently recrystallize. Through this process, an alloy plate for an electrolytic electrode drum was manufactured. Since the rest of the detailed experimental process can be easily understood by those skilled in the art, the detailed description thereof will be omitted.

Experimental Example 1

The Ti-Fe alloy contained 0.03wt% of Fe, the rest of Ti and impurities. The recrystallization temperature was maintained at 750°C. The rest of the experimental process was the same as in the aforementioned experimental example.

Experimental Example 2

The Ti-Fe alloy contained 0.09wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 1 described above.

Experimental Example 3

The Ti-Fe alloy contained 0.15wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 1 described above.

Experimental Example 4

The Ti-Fe alloy contained 0.2wt% Fe, the rest Ti and impurities. The rest of the experimental process was the same as in Experimental Example 1 described above.

Experimental Example 5

The Ti-Fe alloy contained 0.3wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 1 described above.

Experimental Example 6

The Ti-Fe alloy contained 0.5 wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 1 described above.

Experimental Example 7

The Ti-Fe alloy contained 0.03wt% of Fe, the rest of Ti and impurities. The recrystallization temperature was maintained at 700°C. The rest of the experimental process was the same as in the aforementioned experimental example.

Experimental Example 8

The Ti-Fe alloy contained 0.09wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 7 described above.

Experimental Example 9

The Ti-Fe alloy contained 0.15wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 7 described above.

Experimental Example 10

The Ti-Fe alloy contained 0.2wt% Fe, the rest Ti and impurities. The rest of the experimental process was the same as in Experimental Example 7 described above.

Experimental Example 11

The Ti-Fe alloy contained 0.3wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 7 described above.

Experimental Example 12

The Ti-Fe alloy contained 0.5 wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 7 described above.

Experimental Example 13

The Ti-Fe alloy contained 0.03wt% of Fe, the rest of Ti and impurities. The recrystallization temperature was maintained at 650°C. The rest of the experimental process was the same as in the aforementioned experimental example.

Experimental Example 14

The Ti-Fe alloy contained 0.09wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 13 described above.

Experimental Example 15

The Ti-Fe alloy contained 0.15wt% of Fe, the rest of Ti and impurities. The rest of the experimental process was the same as in Experimental Example 14 described above.

Experiment result

Various experiments were conducted to evaluate the characteristics of the Ti-Fe alloy prepared according to Experimental Examples 1 to 6 described above.

phase fraction measurement experiment

The change in the relative amount of the equilibrium phase as a function of the Fe content calculated by Thermo-Calc software was measured for the Ti-Fe alloys of Experimental Examples 2 to 6. Since the details of the experimental process can be understood by those skilled in the art to which the present invention pertains, the detailed description thereof will be omitted.

Phase fraction measurement experiment results

Figure 5 shows a graph measuring the change in the relative amount of the equilibrium phase as a function of the Fe content calculated by Thermo-Calc software. On the right side of FIG. 5 , a rectangular portion indicated by a dotted line on the left side of FIG. 5 is enlarged and shown.

As shown in FIG. 5, in Experimental Examples 2 to 6, the mixture of the α-Ti phase and the Ti-Fe phase was found to be thermodynamically stable. Meanwhile, as the Fe content increased, the amount of the Ti-Fe phase also increased, but the β phase did not exist. That is, the amount of Fe was not sufficient to form or stabilize the β phase.

XRD analysis experiment

The equilibrium phase for a given Ti-Fe composition was calculated using Thermo-Calc software, and the real phase was measured by x-ray diffraction (XRD) using Cu Kα. The above experiments were performed on the Ti-Fe alloys according to Experimental Examples 1 to 6.

XRD analysis test results

6 shows X-ray diffraction graphs of Ti-Fe alloys according to Experimental Examples 1 to 6. In FIG. 6, a black circle represents a portion where an α-Ti phase exists, and a red circle represents a portion where a β-Ti phase exists. The graph on the right of FIG. 6 shows an enlarged X-ray measurement result of the rectangular portion indicated by the dotted line in the left X-ray diffraction graph of FIG. 6, that is, the portion where the β-Ti phase exists. The graph on the right of FIG. 6 shows an enlarged portion of the diffraction angle (2θ) of 55° to 59° of the x-ray diffraction graph on the left of FIG. 6 .

From Experimental Example 4, that is, when the Fe content of the Ti-Fe alloy was 0.3wt% or more, the β-Ti phase began to form, and in Experimental Example 6, the amount of β-Ti phase increased to 1.9wt%. More specifically, as shown in Experimental Example 6 shown in yellow in FIG. 6, it was confirmed that the β-Ti phase increased more significantly than in Experimental Example 5. Therefore, it was found that when the Fe content was 0.2 wt% or more, the corrosion resistance of the Ti-Fe alloy was improved due to the β-Ti phase, and thus it was suitable for use in an electrolytic electrode drum. More preferably, it was suitable that the Fe content was 0.5wt% or more. Meanwhile, a peak corresponding to the Ti-Fe phase did not appear in the XRD graph.

corrosion experiment

Electrochemical experiments were conducted using Autolab PGSTAT302N. Electrochemical experiments were performed in a cell containing three electrodes. That is, the Ti-Fe alloy prepared according to Experimental Example 1, Experimental Example 3, Experimental Example 5, and Experimental Example 6 was used as a working electrode, and the area of the exposed region was 100 mm ² . In addition, a titanium plate was used as a counter electrode and an Ag/AgCl electrode was used as a reference electrode. Dissolved oxygen was removed by purging nitrogen gas with a 30% sulfuric acid solution for 20 min before electrochemical experiments. Corrosion properties were measured by open circuit potential (OCP), electrodynamic polarization and electrochemical impedance spectroscopy (EIS) methods. Then, a spectroscopic experiment was performed to obtain a Tafel plot at a scan rate of 0.05 mV/s in the voltage range of -1.5 V to 1.5 V. Electrochemical Impedance Spectroscopy (EIS) experiments were conducted at an open circuit potential (OCP) with an AC amplitude of 10 mV at frequencies from 10,000 Hz to 0.05 Hz. In the electrochemical impedance spectroscopy experiment, the corrosion characteristics of metal and oxide films used for EIS spectrum analysis were analyzed using an equivalent circuit.

Corrosion test results

Results of various corrosion tests performed on Ti-Fe alloys prepared according to Experimental Examples 1, 3, 5, and 6 will be described below.

Weight change test results according to corrosion

Ti-Fe alloys prepared according to Experimental Example 1, Experimental Example 3, Experimental Example 5, and Experimental Example 6 were divided into primary and secondary, and their weight change and corrosion rate were measured. The experimental results are shown in Table 1 below.

Experimental example order of measurement Weight before experiment (g) Weight after test (g) weight change
(g) corrosion rate
(MPY) Experimental Example 1 Primary 0.2759 0.2712 0.0047 2.62 Secondary 0.3676 0.3615 00061 3.40 Experimental Example 3 Primary 0.2882 0.2808 0.0074 4.13 Secondary 0.3531 0.3448 0.0083 4.60 Experimental Example 5 Primary 0.3471 0.3362 0.0109 6.08 Secondary 0.3586 0.3492 0.0094 5.25 Experimental Example 6 Primary 0.3344 0.3261 0.0083 4.63 Secondary 0.3319 0.3239 0.0000 4.46

As shown in Table 1, the corrosion rate of the Ti-Fe alloy gradually increased from Experimental Example 1 to Experimental Example 3 and Experimental Example 5. However, in Experimental Example 6, the corrosion rate decreased again. These experimental results are schematically illustrated in FIG. 10 to be described in more detail. FIG. 7 is a graph showing corrosion rates of Ti-Fe alloys prepared according to Experimental Examples 1, 3, 5, and 6.

As shown in FIG. 7, the corrosion rate of the Ti-Fe alloy gradually increased as the Fe content increased, but in Experimental Example 6, it was observed that the corrosion rate decreased. On the other hand, since the corrosion rate was less than 6 mm/y in all the experimental examples, it was confirmed that the corrosion resistance of the Fe-Ti alloy to the sulfuric acid electrolyte was quite good.

Corrosion behavior test results

8 (a) and (b) are graphs showing corrosion behavior of Ti-Fe alloys prepared according to Experimental Example 1, Experimental Example 3, Experimental Example 5, and Experimental Example 6. More specifically, (a) of FIG. 8 is a graph showing a change in potential of the working electrode with respect to the reference electrode according to the current density. Then, the rectangle indicated by the dotted line in the graph of FIG. 8 (a) is enlarged and shown as a graph on the right. 8(b) is a graph showing the potential change of the working electrode with respect to the reference electrode according to the immersion time.

In the graph of (a) of FIG. 8, the passivation region of the Ti-Fe alloy prepared according to Experimental Example 1, Experimental Example 3, Experimental Example 5, and Experimental Example 6 was well shown. This meant that the Ti-Fe alloy was well passivated even in the environment of a highly concentrated sulfuric acid solution. The curves of all Ti-Fe alloys prepared according to the above experimental examples showed almost the same trend in terms of corrosion potential, corrosion current density and passivation area.

Looking closely at the nose, that is, the corrosion potential region of the enlarged graph located on the upper right of the graph of FIG. Except for the -Fe alloys, it was found that the cathode reaction shifted in a slightly leaner direction as the amount of Fe added increased.

The graph in (b) of FIG. 8 shows the change in OCP of the aforementioned Ti-Fe alloys according to the immersion time. The Ti-Fe alloys exhibited similar behavior over time. The OCP of Ti-Fe alloys gradually decreased in the first region, the OCP of Ti-Fe alloys rapidly decreased in the second region, and the OCP of Ti-Fe alloys stabilized in the third region. The second region means passivation failure of Ti-Fe alloys, which was caused by the chemical dissolution of the TiO ₂ layer. The difference in Fe content of the Ti-Fe alloys did not have a significant effect in all three regions except for the duration of the first region. The potential of the first region was located in the passivation region, and the potential of the third region was located around the corrosion potential derived from the polarization test. Since the first region is in the passivation region, the duration may indicate passivation stability to acidic electrolytes. This meant that the higher the Fe content of the Ti-Fe alloy, the worse the passivation stability. The gradual destruction of the TiO ₂ compact layer according to the immersion time caused the loss of the protective ability of the TiO ₂ film, resulting in a rapid decrease in the OCP of the Ti-Fe alloy. After OCP decreased, the potential was stabilized at a value close to the corrosion potential, indicating that the Ti-Fe alloy continued to corrode.

Results of electrochemical impedance spectroscopy

9 (a) and (b) show Nyquist plot graphs of Ti-Fe alloys prepared according to Experimental Example 1, Experimental Example 3, Experimental Example 5, and Experimental Example 6. More specifically, the graph of FIG. 9 (a) shows the initial immersion state, and the graph of FIG. 9 (b) shows the immersion state after 1 day.

As shown in (a) of FIG. 9, all of the Ti-Fe alloys prepared according to the above experimental examples exhibited a single wide capacitive loop.

And as shown in (b) of FIG. 9, a change occurred from a single loop to two semicircles as the immersion time elapsed. That is, not only the contraction of the loop diameter but also the change of the loop shape occurred. As the Fe content of the Ti-Fe alloy increased, the crystal grains were refined and the corrosion resistance improved, but it was found that the corrosion resistance of the Ti-Fe alloy decreased when the Fe content exceeded 0.5wt%.

Table 2 below shows the change in the open circuit potential value according to the immersion time according to the electrochemical impedance spectroscopy of the Ti-Fe alloys prepared according to Experimental Example 1, Experimental Example 3, Experimental Example 5, and Experimental Example 6. Here, Rs is the resistance of the sulfuric acid solution used, Rp is the resistance of the porous TiOOH layer where the TiO ₂ layer is dissolved and hydrated on the surface, and Rb is the resistance of the Ti-Fe alloy surface.

Experimental example immersion time Rs Rp Rb Experimental Example 1 0 days 0.860 1420 3.56E+5 1 day 0.665 63.988 40.646 Experimental Example 3 0 days 0.632 1410 2.22E+5 1 day 0.615 60.318 36.472 Experimental Example 5 0 days 0.575 1395 1.17E+5 1 day 0.520 46.435 27.548 Experimental Example 6 0 days 0.768 1387 9.46E+4 1 day 0.840 41.153 21.427

As shown in Table 2, initially, a compact TiO ₂ layer was present on the surface of the Ti—Fe alloy, resulting in a high resistance value (Rb). However, when the Ti-Fe alloy was immersed in a sulfuric acid solution for 1 day, the resistance value decreased as the TiO ₂ layer was dissolved. However, it was found that the difference in corrosion resistance was not large within the aforementioned Fe content. From the resistance value (Rp) data, it was found that the resistance value of the porous TiOOH layer, which was hydrated on the surface by dissolving the TiO ₂ layer after immersion for 1 day, was higher than that of the compact TiO ₂ layer.

Average grain size measurement experiment

The average particle size of the Ti-Fe alloy crystals prepared according to Experimental Examples 1 to 15 was measured through an electron backscatter diffraction (EBSD) experiment. Since the details of the experimental process can be understood by those skilled in the art to which the present invention pertains, the detailed description thereof will be omitted.

Tissue observation test results

10 to 12 show crystal structure analysis photographs of Ti-Fe alloys according to Experimental Examples 1 to 15 of the present invention, respectively. 10 shows photographs of crystal structure analysis of Ti-Fe alloys according to Experimental Examples 1 to 6 of the present invention, and FIG. 11 shows crystal structure analysis of Ti-Fe alloys according to Experimental Examples 7 to 12 of the present invention. 12 shows photographs of crystal structure analysis of Ti-Fe alloys according to Experimental Examples 13 to 15 of the present invention. The average crystal grain size measurement results of the Ti-Fe alloys prepared according to Experimental Examples 1 to 15 are shown in Table 3 below.

Experimental example Fe content in Ti-Fe alloy recrystallization temperature average grain size of crystals Experimental Example 1 0.03wt% 750℃ 94.6㎛ Experimental Example 2 0.09wt% 750℃ 46.4㎛ Experimental Example 3 0.15wt% 750℃ 15.0㎛ Experimental Example 4 0.20wt% 750℃ 11.6㎛ Experimental Example 5 0.30wt% 750℃ 8.2㎛ Experimental Example 6 0.50wt% 750℃ 7.1㎛ Experimental Example 7 0.03wt% 700℃ 66.3㎛ Experimental Example 8 0.09wt% 700℃ 31.0㎛ Experimental Example 9 0.15wt% 700℃ 14.1㎛ Experimental Example 10 0.20wt% 700℃ 10.4㎛ Experimental Example 11 0.30wt% 700℃ 6.0㎛ Experimental Example 12 0.50wt% 700℃ 5.3㎛ Experimental Example 13 0.03wt% 650℃ 25.8㎛ Experimental Example 14 0.09wt% 650℃ 14.1㎛ Experimental Example 15 0.15wt% 650℃ 6.7㎛

As shown in Table 3, the higher the recrystallization temperature, the higher the average grain diameter of the crystals. And it was found that the average grain size of the crystal gradually decreased as the Fe content of the Ti-Fe alloy increased. That is, it was found that as the Fe content increased, the crystal grain refinement effect intended in the experimental example of the present invention was obtained. That is, it was found that the grain growth of the secondary phase of the Ti-Fe phase and the β phase was limited during recrystallization due to Fe. Preferably, it was confirmed that Experimental Examples 4 to 6, Experimental Examples 9 to 12, Experimental Example 14, and Experimental Example 15 had a greater crystal grain refinement effect than other Experimental Examples. Although described accordingly, those working in the technical field to which the present invention belongs will readily understand that various modifications and variations are possible without departing from the concept and scope of the claims described below.

10. Electrolytic electrode drum
20. Cathode material
30. Electrolyzer
40. Transfer rolls
50. Winding roll
100. Copper foil manufacturing equipment
101. Plates
103. Cylindrical Rotating Body
105. Rotational axis
C. copper foil
S. aqueous solution of sulfuric acid

Claims (10)

As an electrolytic electrode drum for producing copper foil,
a cylindrical body of revolution, and
Plate material attached to the surface of the cylindrical rotating body
including,
The plate material is an electrolytic electrode drum containing 0.15wt% to 0.5wt% of Fe, the remainder Ti and other impurities. In paragraph 1,
The electrolytic electrode drum wherein the amount of the β-Ti phase contained in the plate is 0.1 wt% to 1.9 wt%. In paragraph 1,
The electrolytic electrode drum wherein the average grain diameter of the crystals of the plate material is 30 μm or less. In paragraph 3,
The average particle diameter of the crystals of the plate material is 10 μm to 30 μm electrolytic electrode drum. In paragraph 3,
The average particle diameter of the crystals of the plate material is 5.3 μm to 15.0 μm electrolytic electrode drum. In paragraph 1,
The amount of Fe is 0.2wt% to 0.5wt% of the electrolytic electrode drum. As a method for producing an electrolytic electrode drum for copper foil production,
providing a cylindrical core; and
providing a plate material on the surface of the cylindrical core;
including,
The step of providing the plate material,
providing an ingot;
Melting the ingot a plurality of times at 1700 ° C to 1800 ° C;
Homogenization heat treatment of the ingot at 900 ° C to 1100 ° C for 5 hours to 15 hours in a vacuum atmosphere of 10 ^-6 torr to 10 ^-4 torr,
Preparing a rolled material by hot rolling the ingot at a rolling reduction of 70% to 90% at 600 ° C to 800 ° C, and
Recrystallizing the rolled material by annealing at 600 ° C to 750 ° C for 30 to 90 minutes
including,
In the step of providing the plate material, the plate material comprises 0.15wt% to 0.5wt% of Fe, the remainder Ti and other impurities. In paragraph 7,
In the step of recrystallizing the rolled material, the manufacturing method of the electrolytic electrode drum of annealing the rolled material at 650 ℃ to 750 ℃. In paragraph 7,
The amount of the β-Ti phase contained in the plate material is 0.1wt% to 1.9wt%, and the β-Ti phase is located at the grain boundary of the plate material. In paragraph 7,
In the step of providing the plate material, the amount of Fe is 0.2wt% to 0.5wt%.

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