Mo-nb microalloyed stainless steel current collector and preparation method thereof

Abstract

The application discloses a Mo-Nb micro-alloyed stainless steel current collector and a preparation method thereof, and relates to the technical field of current collectors.The preparation method of the Mo-Nb micro-alloyed stainless steel current collector comprises the following steps: S1, preparing a molybdenum-chromium sputtering target and a niobium-chromium sputtering target by respectively melting molybdenum pure metal and niobium pure metal with chromium pure metal; S2, sequentially polishing, polishing, washing, drying and obtaining a pretreated stainless steel plate; S3, placing the pretreated stainless steel plate at a workpiece pole in a three-cathode glow ion metal penetration furnace, taking the molybdenum-chromium sputtering target and the niobium-chromium sputtering target as double-source levels, and performing glow ion plating treatment to obtain the Mo-Nb micro-alloyed stainless steel current collector.The stainless steel current collector prepared by the application has excellent corrosion resistance and a low interface contact resistance.

Description

Technical Field

[0001] This invention relates to the field of current collector technology, specifically a Mo-Nb microalloyed stainless steel current collector and its preparation method. Background Technology

[0002] With the continuous development of technology, current collectors, as key current transmission components in electrochemical systems, need to have excellent conductivity, corrosion resistance, and mechanical strength. Stainless steel, as a commonly used metal material, has excellent mechanical properties and good corrosion resistance. However, in battery electrolytes, especially in corrosive environments containing chloride ions, the corrosion resistance of stainless steel needs to be further improved. At the same time, it is also necessary to ensure that the surface of stainless steel has a low interfacial contact resistance to improve battery performance.

[0003] In summary, solving the above problems and preparing a stainless steel current collector with good corrosion resistance and low interfacial contact resistance is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a Mo-Nb microalloyed stainless steel current collector and its preparation method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A method for preparing a Mo-Nb microalloyed stainless steel current collector includes the following steps:

[0007] S1: Molybdenum-chromium sputtering targets and niobium-chromium sputtering targets are prepared by melting pure molybdenum metal and pure niobium metal with pure chromium metal, respectively.

[0008] S2: The stainless steel sheet is successively ground, polished, washed, and dried to obtain a pretreated stainless steel sheet.

[0009] S3: The pretreated stainless steel plate is placed at the workpiece electrode in a three-cathode glow discharge ion diffusion furnace. Molybdenum-chromium sputtering target and niobium-chromium sputtering target are used as dual-source stages for glow discharge ion diffusion treatment to obtain Mo-Nb microalloyed stainless steel current collector.

[0010] Preferably, in the molybdenum-chromium sputtering target, the mass ratio of molybdenum to chromium is 3:1 to 1.5; in the niobium-chromium sputtering target, the mass ratio of niobium to chromium is 3:1 to 1.5; and the stainless steel plate is of either 304 stainless steel or 316 stainless steel.

[0011] Preferably, the specific steps in the glow discharge ion plating process are as follows: evacuating the furnace to a vacuum level of 3×10⁻⁶. -2Then, argon gas is introduced and adjusted to the working pressure. The glow discharge is started, and the workpiece is heated to the working temperature. The holding time is then calculated. After the holding time is completed, the Mo-Nb microalloyed stainless steel current collector is obtained.

[0012] Preferably, the working pressure of the argon gas is 30~40 Pa, the working temperature is 900~1000℃, and the heat preservation time is 3~4 h.

[0013] Preferably, during the glow discharge activation process, glow discharge ion diffusion is performed simultaneously at dual sources. The specific process is as follows: first, the voltage at the workpiece electrode is applied, and then the voltages at the source electrode of the molybdenum-chromium sputtering target and the source stage of the niobium-chromium sputtering target are applied simultaneously.

[0014] Preferably, the voltage at the workpiece electrode is 500~600V, the voltage at the source electrode of the molybdenum-chromium sputtering target is 900~950V, and the voltage at the source electrode of the niobium-chromium sputtering target is 850~900V; the distance between the molybdenum-chromium sputtering target and the workpiece electrode is the same as the distance between the niobium-chromium sputtering target and the workpiece electrode, which is 15~20mm.

[0015] Preferably, during the glow discharge activation process, glow discharge ion diffusion is performed alternately by two sources. The specific process is as follows: first, the voltage at the workpiece electrode is applied, and then the voltages at the source electrode of the molybdenum-chromium sputtering target and the source stage of the niobium-chromium sputtering target are applied simultaneously. After the workpiece temperature rises to the working temperature and is held for 10-15 minutes, the voltages at the source electrode of the molybdenum-chromium sputtering target and the source stage of the niobium-chromium sputtering target are switched alternately in a cyclic manner.

[0016] Preferably, the voltage at the workpiece electrode is 500~600V, the voltage at the source electrode of the molybdenum-chromium sputtering target is 900~950V, and the voltage at the source electrode of the niobium-chromium sputtering target is 850~900V; the distance between the molybdenum-chromium sputtering target and the workpiece electrode is the same as the distance between the niobium-chromium sputtering target and the workpiece electrode, which is 15~20mm; and the interval of the cyclic alternating switch is 5~20min.

[0017] Preferably, during the ion plating process, when the holding time reaches 1.5 to 2 hours, nitrogen gas is introduced and the flow rate is adjusted to a pressure of 25 to 30 Pa to continue the glow discharge ion plating treatment.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention prepares niobium-chromium alloy and molybdenum-chromium alloy as sputtering targets as dual-source stages, and uses glow discharge ion diffusion plating process to prepare a Mo-Nb microalloyed diffusion coating with chromium as the main component on the surface of stainless steel plate. The resulting stainless steel current collector has excellent corrosion resistance and low interfacial contact resistance.

[0019] In the glow discharge ion plating process, the sputtered alloy at the source stage emits source metal ions under the action of a high-energy electric field. These ions impact the workpiece surface at high speed, raising the workpiece temperature and simultaneously diffusing on the workpiece surface to form a microalloy layer. Molybdenum and niobium are adjacent in the periodic table and have similar physical properties, but they also differ, resulting in different segregation effects. Molybdenum tends to form stable grain boundaries, while niobium tends to form finer particles. This synergistic effect inhibits grain growth and refines the grain size. In acid and chloride ion solutions, chromium can synergistically suppress intergranular corrosion in stainless steel, significantly improving the corrosion resistance of stainless steel current collectors. Chromium, on the other hand, possesses certain corrosion resistance and good alloying ability, which helps promote the uniformity and efficiency of molybdenum and niobium microalloying. Compared to tungsten, chromium has better corrosion resistance, lower cost, and good electrical conductivity.

[0020] In the glow discharge ion plating process, when nitrogen gas is introduced after a total holding time of 1-2 hours, the nitrogen is ionized under the glow discharge effect and reacts with metal ions of molybdenum, niobium, and chromium to form nitrides. This improves the chemical stability of the coating, fills pores and defects in the coating, increases density, and promotes microalloying of the coating, forming continuous conductive pathways and thus reducing interfacial contact resistance. However, the nitriding process cannot be carried out at the beginning of the process. In the early stages of glow discharge ion plating, the deposited alloy layer has not yet fully formed, and the formed nitrides may hinder microalloying, causing stress within the coating that easily leads to cracking, poor adhesion to the substrate, and reduced corrosion resistance.

[0021] During nitride formation, the nitride metal film grows in a columnar crystal structure. During this growth, the columnar crystals compete with each other; that is, once a columnar crystal stops growing, secondary nucleation will not occur even if other well-developed columnar crystals exist around it, leading to porosity and reduced corrosion resistance. Although the introduction of molybdenum and niobium can, to some extent, inhibit columnar crystal formation as heterogeneous phases, the effect is limited. Therefore, this invention employs an alternating voltage switching method at the source stages of molybdenum-chromium sputtering targets and niobium-chromium sputtering targets to prepare a multilayer alternating molybdenum-chromium and niobium-chromium layer structure on the stainless steel surface. Compared with co-diffusion plating, this method can significantly improve the uniformity and density of the coating. On the one hand, niobium and molybdenum have similar properties, excellent interlayer bonding, and are not easily detached, which also promotes the efficiency and uniformity of microalloying. No additional treatment is required after fabrication. On the other hand, during the nitriding process, the stacked structure interrupts the growth of columnar crystals, resulting in short and fine columnar crystals, which further improves the density of the coating, promotes the formation of conductive pathways, thereby improving corrosion resistance and reducing interfacial contact resistance. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that the following quantities are by weight. There are no special restrictions on the purchase of any of the raw materials involved in this invention; they are all commercially available. The stainless steel plates used in the examples and comparative examples are all 304 stainless steel.

[0024] Example 1: A method for preparing a Mo-Nb microalloyed stainless steel current collector specifically includes the following steps:

[0025] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 3:1; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 3:1.

[0026] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0027] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2 Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After rinsing, argon gas is introduced again, and the working pressure of the argon gas is adjusted to 35 Pa. The process parameters are set as follows: the voltage at the workpiece electrode is 550 V, the voltage at the source stage of the molybdenum-chromium sputtering target is 925 V, the voltage at the source stage of the niobium-chromium sputtering target is 875 V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15 mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15 mm. Glow photoluminescence is started: after applying the voltage at the workpiece electrode, the voltages at the source stages of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are applied simultaneously. The workpiece is heated to a working temperature of 950 °C, and the holding time is calculated. The holding time is 3 h. When the holding time reaches 1.5 h, nitrogen gas is introduced, and the flow rate is adjusted to a pressure of 25 Pa to continue glow photoluminescence ion diffusion treatment. After the holding time is completed, Mo-Nb microalloyed stainless steel current collector is obtained.

[0028] Example 2: A method for preparing a Mo-Nb microalloyed stainless steel current collector specifically includes the following steps:

[0029] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 3:1.5; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 3:1.5.

[0030] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0031] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2 Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After rinsing, argon gas is introduced again, and the working pressure of the argon gas is adjusted to 35 Pa. The process parameters are set as follows: the voltage at the workpiece electrode is 550 V, the voltage at the source stage of the molybdenum-chromium sputtering target is 925 V, the voltage at the source stage of the niobium-chromium sputtering target is 875 V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15 mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15 mm. Glow photoluminescence is started: after applying the voltage at the workpiece electrode, the voltages at the source stages of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are applied simultaneously. The workpiece is heated to a working temperature of 950 °C, and the holding time is calculated. The holding time is 3 h. When the holding time reaches 1.5 h, nitrogen gas is introduced, and the flow rate is adjusted to a pressure of 25 Pa to continue glow photoluminescence ion diffusion treatment. After the holding time is completed, Mo-Nb microalloyed stainless steel current collector is obtained.

[0032] Example 3: A method for preparing a Mo-Nb microalloyed stainless steel current collector specifically includes the following steps:

[0033] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 3:1; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 3:1.

[0034] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0035] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After rinsing, argon gas is introduced again, and the working pressure of the argon gas is adjusted to 35 Pa. The process parameters are set as follows: the voltage at the workpiece electrode is 550 V, the voltage at the source stage of the molybdenum-chromium sputtering target is 900 V, the voltage at the source stage of the niobium-chromium sputtering target is 900 V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15 mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15 mm. Glow photoluminescence is started: after applying the voltage at the workpiece electrode, the voltages at the source stages of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are applied simultaneously. The workpiece is heated to a working temperature of 950 °C, and the holding time is calculated. The holding time is 3 h. When the holding time reaches 1.5 h, nitrogen gas is introduced, and the flow rate is adjusted to a pressure of 25 Pa to continue glow photoluminescence ion diffusion treatment. After the holding time is completed, Mo-Nb microalloyed stainless steel current collector is obtained.

[0036] Example 4: A method for preparing a Mo-Nb microalloyed stainless steel current collector specifically includes the following steps:

[0037] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 3:1; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 3:1.

[0038] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0039] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After purging, argon gas is introduced again, and the working argon gas pressure is adjusted to 35 Pa. The process parameters are set as follows: voltage at the workpiece electrode is 550V, voltage at the source stage of the molybdenum-chromium sputtering target is 925V, voltage at the source stage of the niobium-chromium sputtering target is 875V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15mm; glow discharge is initiated: after applying the voltage at the workpiece electrode, the voltage at the source stage of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are simultaneously applied. The voltage at the source stage was set, and after heating the workpiece to a working temperature of 950℃, the holding time was calculated and set to 3 hours. After holding for 10 minutes, the voltage at the source electrode of the molybdenum-chromium sputtering target and the voltage at the source stage of the niobium-chromium sputtering target were alternately switched on and off cyclically (first turning off the voltage at the source stage of the niobium-chromium sputtering target) at intervals of 10 minutes. When the holding time reached 1.5 hours, nitrogen gas was introduced and the flow rate was adjusted to a pressure of 25 Pa to continue the glow discharge ion deposition treatment. After the holding time was completed, the Mo-Nb microalloyed stainless steel current collector was obtained.

[0040] Example 5: A method for preparing a Mo-Nb microalloyed stainless steel current collector specifically includes the following steps:

[0041] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 3:1; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 3:1.

[0042] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0043] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After purging, argon gas is introduced again, and the working argon gas pressure is adjusted to 35 Pa. The process parameters are set as follows: voltage at the workpiece electrode is 550V, voltage at the source stage of the molybdenum-chromium sputtering target is 925V, voltage at the source stage of the niobium-chromium sputtering target is 875V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15mm; glow discharge is initiated: after applying the voltage at the workpiece electrode, the voltage at the source stage of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are simultaneously applied. The voltage at the source stage was set, and after heating the workpiece to a working temperature of 950℃, the holding time was calculated and set to 3 hours. After holding for 10 minutes, the voltage at the source electrode of the molybdenum-chromium sputtering target and the voltage at the source stage of the niobium-chromium sputtering target were alternately switched on and off (first turning off the voltage at the source stage of the molybdenum-chromium sputtering target) at 10-minute intervals. When the holding time reached 1.5 hours, nitrogen gas was introduced and the flow rate was adjusted to a pressure of 25 Pa to continue the glow discharge ion deposition treatment. After the holding time was completed, the Mo-Nb microalloyed stainless steel current collector was obtained.

[0044] Example 6: A method for preparing a Mo-Nb microalloyed stainless steel current collector specifically includes the following steps:

[0045] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 3:1; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 3:1.

[0046] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0047] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After purging, argon gas is introduced again, and the working argon gas pressure is adjusted to 35 Pa. The process parameters are set as follows: voltage at the workpiece electrode is 550V, voltage at the source stage of the molybdenum-chromium sputtering target is 925V, voltage at the source stage of the niobium-chromium sputtering target is 875V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15mm; glow discharge is initiated: after applying the voltage at the workpiece electrode, the voltage at the source stage of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are simultaneously applied. The voltage at the source stage was set, and after heating the workpiece to a working temperature of 950℃, the holding time was calculated and set to 3 hours. After holding for 10 minutes, the voltage at the source electrode of the molybdenum-chromium sputtering target and the voltage at the source stage of the niobium-chromium sputtering target were alternately switched on and off cyclically (first turning off the voltage at the source stage of the niobium-chromium sputtering target) at intervals of 20 minutes. When the holding time reached 1.5 hours, nitrogen gas was introduced and the flow rate was adjusted to a pressure of 25 Pa to continue the glow discharge ion deposition treatment. After the holding time was completed, the Mo-Nb microalloyed stainless steel current collector was obtained.

[0048] Comparative Example 1: Based on Example 1, tungsten was used to replace chromium in the preparation of the sputtering target, while the rest of the process remained unchanged, as follows:

[0049] S1: A molybdenum-tungsten sputtering target is prepared by melting pure molybdenum metal and pure tungsten metal at a mass ratio of 3:1; a niobium-tungsten sputtering target is prepared by melting pure niobium metal and pure tungsten metal at a mass ratio of 3:1.

[0050] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0051] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ion diffusion furnace, using molybdenum-tungsten sputtering targets and niobium-tungsten sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After rinsing, argon gas is introduced again, and the working pressure of the argon gas is adjusted to 35 Pa. The process parameters are set as follows: the voltage at the workpiece electrode is 550 V, the voltage at the source stage of the molybdenum-tungsten sputtering target is 925 V, the voltage at the source stage of the niobium-tungsten sputtering target is 875 V, the distance between the molybdenum-tungsten sputtering target and the workpiece electrode is 15 mm, and the distance between the niobium-tungsten sputtering target and the workpiece electrode is 15 mm. Glow photoluminescence is started: after applying the voltage at the workpiece electrode, the voltages at the source stages of the molybdenum-tungsten sputtering target and the niobium-tungsten sputtering target are applied simultaneously. The workpiece is heated to a working temperature of 950 °C, and the holding time is calculated. The holding time is 3 h. When the holding time reaches 1.5 h, nitrogen gas is introduced, and the flow rate is adjusted to a pressure of 25 Pa to continue glow photoluminescence ion diffusion treatment. After the holding time is completed, Mo-Nb microalloyed stainless steel current collector is obtained.

[0052] Comparative Example 2: Based on Example 1, the chromium ratio in the molybdenum-chromium sputtering target and the niobium-chromium sputtering target was changed, while the other processes remained unchanged, as follows:

[0053] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 1:3; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 1:3.

[0054] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0055] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2 Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After rinsing, argon gas is introduced again, and the working pressure of the argon gas is adjusted to 35 Pa. The process parameters are set as follows: the voltage at the workpiece electrode is 550 V, the voltage at the source stage of the molybdenum-chromium sputtering target is 925 V, the voltage at the source stage of the niobium-chromium sputtering target is 875 V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15 mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15 mm. Glow photoluminescence is started: after applying the voltage at the workpiece electrode, the voltages at the source stages of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are applied simultaneously. The workpiece is heated to a working temperature of 950 °C, and the holding time is calculated. The holding time is 3 h. When the holding time reaches 1.5 h, nitrogen gas is introduced, and the flow rate is adjusted to a pressure of 25 Pa to continue glow photoluminescence ion diffusion treatment. After the holding time is completed, Mo-Nb microalloyed stainless steel current collector is obtained.

[0056] Comparative Example 3: Based on Example 1, nitrogen gas was introduced at the beginning of the glow discharge nitriding process, while the rest of the process remained unchanged, as follows:

[0057] S1: A molybdenum-chromium sputtering target is prepared by melting pure molybdenum metal and pure chromium metal at a mass ratio of 3:1; a niobium-chromium sputtering target is prepared by melting pure niobium metal and pure chromium metal at a mass ratio of 3:1.

[0058] S2: The stainless steel plate is sanded and polished with 2000-grit sandpaper, washed with acetone and ethanol respectively, and dried to obtain a pre-treated stainless steel plate.

[0059] S3: Place the pretreated stainless steel plate at the workpiece electrode in the three-cathode glow discharge ionization furnace, using molybdenum-chromium sputtering targets and niobium-chromium sputtering targets as dual-source stages, and evacuate to 3×10⁻⁶. -2 Afterwards, argon gas is introduced to perform ion rinsing on the workpiece and target surfaces. After rinsing, argon gas is introduced again, and the working pressure of the argon gas is adjusted to 35 Pa. The process parameters are set as follows: the voltage at the workpiece electrode is 550 V, the voltage at the source stage of the molybdenum-chromium sputtering target is 925 V, the voltage at the source stage of the niobium-chromium sputtering target is 875 V, the distance between the molybdenum-chromium sputtering target and the workpiece electrode is 15 mm, and the distance between the niobium-chromium sputtering target and the workpiece electrode is 15 mm. Glow photoluminescence is started: after applying the voltage at the workpiece electrode, the voltages at the source stages of the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are simultaneously applied. The workpiece is heated to a working temperature of 950 °C, and the holding time is calculated to be 3 h. Nitrogen gas is introduced simultaneously with the start of glow photoluminescence, and the flow rate is adjusted to a pressure of 25 Pa to continue glow photoluminescence ion diffusion treatment. After the holding time is completed, Mo-Nb microalloyed stainless steel current collector is obtained.

[0060] Performance testing: (1) Electrochemical testing was conducted on the stainless steel current collectors prepared in each embodiment and comparative example: using the stainless steel current collector as the working electrode, and with a 20×20mm electrode... 2 A platinum mesh was used as the counter electrode, and an Ag / AgCl electrode filled with saturated potassium chloride solution was used as the reference electrode (standard electrode potential of +0.199V). The contact area between the current collector and the electrolyte was 1 cm². 2 The electrolyte is 0.5M sulfuric acid and 2ppm F. -The temperature is 70℃, hydrogen and oxygen need to be introduced into the electrolyte, the dynamic potential test range is -0.6~1.2V, and the scanning rate is 1mV / s; (2) The stainless steel current collectors prepared in each example and comparative example are subjected to interface contact resistance test: the copper sheet, carbon paper, stainless steel current collector, carbon paper and copper sheet are stacked in the order of copper sheet, carbon paper and copper sheet, and a universal testing machine is used to apply load to it. The voltage values ​​under different pressures under a constant current of 100mA are recorded, and the total resistance R1 is calculated. Then, the total resistance R2 under the corresponding pressure is recorded in the same way according to the order of copper sheet, carbon paper and copper sheet. The interface contact resistance value is calculated according to the formula [(R1-R2) / 2]×S (S is the contact area of ​​the stainless steel current collector).

[0061]

[0062] Conclusion: As shown in the table, this invention prepares niobium-chromium alloy and molybdenum-chromium alloy as sputtering targets as dual-source stages, and uses glow discharge ion diffusion plating process to prepare a Mo-Nb microalloyed diffusion coating with chromium as the main component on the surface of stainless steel plate. The resulting stainless steel current collector has excellent corrosion resistance and low interfacial contact resistance.

[0063] In Comparative Example 1, tungsten was used to replace chromium in the sputtering target, which made it difficult to promote the microalloying of molybdenum and niobium, resulting in lower corrosion resistance and conductivity compared to Example 1. In Comparative Example 2, the ratio of chromium in the molybdenum-chromium sputtering target and the niobium-chromium sputtering target was changed, which reduced the effect of promoting the microalloying of molybdenum and niobium, decreased uniformity and efficiency, reduced corrosion resistance, and increased interfacial contact resistance. In Comparative Example 3, nitrogen gas was introduced at the beginning of the glow discharge nitriding process, and the resulting nitrides may hinder the microalloying process, causing stress in the coating and making it prone to cracking. The coating also had poor adhesion to the substrate, resulting in reduced corrosion resistance. Compared with Examples 1-3, Examples 4-6 used an alternating diffusion plating method to prepare Mo-Nb microalloyed diffusion coatings with chromium as the main component, and the performance was significantly better than that of Examples 1-3. This shows that the alternating diffusion plating scheme can significantly improve the uniformity of the coating, reduce the coating stress, and inhibit the formation of columnar crystals, thereby improving corrosion resistance and reducing interfacial contact resistance. The niobium-chromium layer had the best performance when it was on the outermost layer (the voltage at the source stage of the niobium-chromium sputtering target was turned off first).

[0064] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of producing a Mo-Nb microalloyed stainless steel current collector, characterized by, The method comprises the following steps: S1: pure molybdenum and pure niobium are respectively melted with pure chromium to prepare a molybdenum-chromium sputtering target and a niobium-chromium sputtering target; S2: a stainless steel plate is sequentially polished, polished, washed, dried, and obtained as a pretreated stainless steel plate; S3: the pretreated stainless steel plate is placed at a workpiece electrode in a three-cathode glow ion metal penetration furnace, the molybdenum-chromium sputtering target and the niobium-chromium sputtering target are used as double-source stages, and glow ion plating treatment is performed to obtain a Mo-Nb micro-alloyed stainless steel current collector. In the molybdenum-chromium sputtering target, the mass ratio of molybdenum to chromium is 3:1-1.5; in the niobium-chromium sputtering target, the mass ratio of niobium to chromium is 3:1-1.

5. The process of the glow ion implantation process includes the following steps: vacuumizing the furnace to 3*10 -2 After that, argon is introduced and adjusted to the working pressure, the glow is started, the workpiece is heated to the working temperature, the holding time is started to be calculated, and the Mo-Nb micro-alloyed stainless steel current collector is obtained after the holding time ends. In the process of the glow ion plating treatment, when the holding time reaches 1.5-2 h, nitrogen gas is started to be introduced, the flow rate is adjusted to a pressure of 25-30 Pa, and the glow ion plating treatment is continuously performed.

2. The preparation method of the Mo-Nb micro-alloyed stainless steel current collector according to claim 1, characterized in that: The model of the stainless steel plate includes one of 304 stainless steel or 316 stainless steel.

3. The preparation method of the Mo-Nb microalloyed stainless steel current collector according to claim 1, characterized in that: The working pressure of the argon gas is 30-40 Pa, the working temperature is 900-1000°C, and the holding time is 3-4 h.

4. The preparation method of the Mo-Nb micro-alloyed stainless steel current collector according to claim 1, characterized in that: In the process of starting the glow, the double-source stages are simultaneously subjected to glow ion plating, and the specific process is that the voltage at the workpiece electrode is first loaded, and then the voltages at the molybdenum-chromium sputtering target source electrode and the niobium-chromium sputtering target source stage are simultaneously loaded.

5. The method of claim 4, wherein the Mo-Nb microalloyed stainless steel current collector is prepared by the steps of: The voltage at the workpiece electrode is 500-600 V, the voltage at the molybdenum-chromium sputtering target source electrode is 900-950 V, and the voltage at the niobium-chromium sputtering target source electrode is 850-900 V; the distance between the molybdenum-chromium sputtering target and the workpiece electrode is the same as the distance between the niobium-chromium sputtering target and the workpiece electrode, and the distance is 15-20 mm. ​ 6. The method of claim 1, wherein the Mo-Nb microalloyed stainless steel current collector is prepared by the steps of: In the process of starting the glow, the double-source stages are alternately subjected to glow ion plating, and the specific process is that the voltage at the workpiece electrode is first loaded, and then the voltages at the molybdenum-chromium sputtering target source electrode and the niobium-chromium sputtering target source stage are simultaneously loaded; after the workpiece temperature is raised to the working temperature and is held for 10-15 min, the voltage at the molybdenum-chromium sputtering target source electrode and the voltage at the niobium-chromium sputtering target source stage are alternately turned on and off. ​ 7. The method of claim 6, wherein the Mo-Nb microalloyed stainless steel current collector is prepared by the steps of: The voltage at the workpiece electrode is 500-600 V, the voltage at the molybdenum-chromium sputtering target source electrode is 900-950 V, and the voltage at the niobium-chromium sputtering target source electrode is 850-900 V; the distance between the molybdenum-chromium sputtering target and the workpiece electrode is the same as the distance between the niobium-chromium sputtering target and the workpiece electrode, and the distance is 15-20 mm; and the interval of the alternately turning on and off is 5-20 min. ​ 8. A Mo-Nb micro-alloyed stainless steel current collector prepared by the preparation method of the Mo-Nb micro-alloyed stainless steel current collector according to any one of claims 1-7.

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