阅读说明：本技术 一种在锂电池生产用轧辊表面制备氮化钛膜层的方法 (Method for preparing titanium nitride film layer on surface of roller for lithium battery production ) 是由 马小军 于 2021-08-28 设计创作，主要内容包括：本发明涉及一种在锂电池生产用轧辊表面制备氮化钛膜层的方法,包括步骤(1)对锂电池生产用轧辊表面进行预处理；(2)将预处理后轧辊固定在氮化炉内工件台上进行自转,并将钛或者钛合金靶材装配在靶材工装上；(3)对氮化炉进行抽真空后通入氮气；(4)以轧辊为阴极,氮化炉为阳极,在轧辊和氮化炉之间加载直流脉冲高压电进行通电,氮气发生电离,轧辊周围含氮气体产生辉光放电,进行离子渗氮处理；(5)离子渗氮处理后,经离子源向氮化炉内注入氮化钛离子束,调节氮化钛离子束注入的温度、能量、束流和剂量,对轧辊表面进行高能离子注入处理,冷却至室温,形成氮化钛膜层。本发明耐磨性及结合强度好,表面硬度高,孔隙率底,不会剥落。(The invention relates to a method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery, which comprises the following steps of (1) pretreating the surface of the roller for producing the lithium battery; (2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, and assembling a titanium or titanium alloy target on a target tool; (3) vacuumizing the nitriding furnace and introducing nitrogen; (4) loading direct current pulse high voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, ionizing nitrogen, generating glow discharge by nitrogen-containing gas around the roller, and performing ion nitriding treatment; (5) and after the ion nitriding treatment, injecting titanium nitride ion beams into the nitriding furnace through an ion source, adjusting the injection temperature, energy, beam current and dosage of the titanium nitride ion beams, performing high-energy ion injection treatment on the surface of the roller, and cooling to room temperature to form a titanium nitride film layer. The invention has good wear resistance and bonding strength, high surface hardness, low porosity and no peeling.)

1. A method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery is characterized by comprising the following steps: which comprises the following steps:

(1) pretreating the surface of a roller for producing a lithium battery;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, and assembling a titanium or titanium alloy target on a target tool;

(3) vacuumizing the nitriding furnace and introducing nitrogen;

(4) loading direct current pulse high voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, ionizing nitrogen, generating glow discharge by nitrogen-containing gas around the roller, and performing ion nitriding treatment;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to be less than 100 ℃, the energy is 70-120 kev, the beam current is 5-20 mA, and the dosage is 1.0 multiplied by 10¹⁷/cm²～3.5×10¹⁸/cm²And performing high-energy ion implantation treatment on the surface of the roller, and cooling to room temperature to form a titanium nitride film layer.

2. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 1, wherein the method comprises the following steps: the pretreatment in the step (1) is to polish the surface of the roller for lithium battery production, the surface roughness after polishing is 0.01-0.05 mu m, then ultrasonic oscillation cleaning is carried out for 2-5 times by adopting acetone solution or ethanol solution, each cleaning is carried out for 15-30 minutes, and drying is carried out for later use.

3. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 1, wherein the method comprises the following steps: the roller for producing the lithium battery in the step (1) is made of 9Cr2Mo, 9Cr3Mo, hard aluminum alloy or titanium alloy.

4. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 1, wherein the method comprises the following steps: and (3) in the step (2), the rotation speed of the roller is 15-30 revolutions per minute.

5. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 1, wherein the method comprises the following steps: and (3) vacuumizing until the vacuum degree reaches 10-50 Pa.

6. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 5, wherein the method comprises the following steps: and (4) in the step (3), the working air pressure of the nitriding furnace after nitrogen is introduced is 0.01-0.1 Pa.

7. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 1, wherein the method comprises the following steps: in the step (4), the voltage of the direct current pulse high voltage is-500 to-1000V, and the current is 1 to 5A.

8. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 1, wherein the method comprises the following steps: and (5) before cooling in the step (5), low-temperature tempering treatment is required, wherein the tempering temperature is less than 100 ℃.

9. The method for preparing the titanium nitride film layer on the surface of the roller for producing the lithium battery as claimed in claim 1, wherein the method comprises the following steps: and (5) the thickness of the titanium nitride film layer is 2-5 mu m.

Technical Field

The invention relates to the technical field of lithium battery production, in particular to a method for preparing a titanium nitride film layer on the surface of a roller for lithium battery production.

Background

At present, the lithium battery pole piece is generally rolled and compacted continuously by a double-roller machine, in the process, the pole piece coated with particle coatings on two surfaces is fed into a gap between two rollers, the coatings are compacted under the action of the linear load of the rollers, all parts of the pole piece are uniform, the thickness difference is within several micrometers, and therefore the rollers are required to have extremely high hardness, extremely high hardness uniformity and higher capability of resisting extrusion deformation of foreign objects. In the prior art, the rolling linear speed of lithium battery manufacturers at home and abroad is generally developed at a speed of several meters per minute to dozens of meters per minute, and the rolling force is between 50 and 200 tons, so that the requirements on the roller are higher and higher. Because the positive electrode material and the negative electrode material of the lithium battery are very hard in single composition particles in drying and large in rolling force, after the roller continuously works for a long time, a fatigue layer is generated on the roller surface, particularly, a positive electrode plate is continuously extruded through coating particles, slight indentation can be left on the roller surface, the surface quality of the roller is continuously reduced, the roller is generally used for about 25-30 days seriously, and when the indentation seriously affects the quality of the electrode plate to a certain degree, the roller needs to be replaced so as to avoid affecting the surface of the battery electrode plate; meanwhile, electrochemical corrosion of some pole piece materials and some components in the alloy steel is formed, and the quality reduction of the roll surface is accelerated. Besides the abrasion problem in the rolling process, the problems that the local stress of the roller exceeds the elastic modulus of the material due to the surface defect of the pole piece, the local crushing is caused, the affinity between the material of the roller and the components of the pole piece is generated, the spot corrosion generated by the corrosion on the surface of the roller easily causes the adhesion, the corrosion on the surface of the pole piece roller is caused by the moisture in the environment and the corrosion of chemical substances in the pole piece, and the like exist.

In order to solve the problems, most lithium battery manufacturers perform material surface technical treatment on the roller, and a common material surface technology is to coat or electroplate a wear-resistant material such as tungsten carbide and the like on the surface of the roller by adopting a coating technology to form a coating or a plating layer.

Disclosure of Invention

The invention aims to provide a method for preparing a titanium nitride film layer on the surface of a roller for lithium battery production, which has the advantages of reasonable design, simple process, capability of effectively improving the surface wear resistance of the roller and prolonging the service life, aiming at the condition of the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery comprises the following steps:

(1) pretreating the surface of a roller for producing a lithium battery;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, and assembling a titanium or titanium alloy target on a target tool;

(3) vacuumizing the nitriding furnace and introducing nitrogen;

(4) loading direct current pulse high voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, ionizing nitrogen, generating glow discharge by nitrogen-containing gas around the roller, and performing ion nitriding treatment;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to be less than 100 ℃, the energy is 70-120 kev, the beam current is 5-20 mA, and the dosage is 1.0 multiplied by 10¹⁷/cm²～3.5×10¹⁸/cm²And performing high-energy ion implantation treatment on the surface of the roller, and cooling to room temperature to form a titanium nitride film layer.

Preferably, the pretreatment in the step (1) is to polish the surface of a roller for lithium battery production, the surface roughness after polishing is 0.01-0.05 μm, then ultrasonic oscillation cleaning is carried out for 2-5 times by adopting an acetone solution or an ethanol solution, each cleaning is carried out for 15-30 minutes, and drying is carried out for later use.

Preferably, the material of the roller for producing the lithium battery in the step (1) is 9Cr2Mo, 9Cr3Mo, a hard aluminum alloy or a titanium alloy. The 9Cr2Mo material in the design is typical Cr2 series cold roll steel, and 9Cr3Mo is roll steel for satin steel; the hard aluminum alloy is Al-Cu-Mg alloy, Cu and Mg can form a strengthening phase, and higher strength and hardness can be obtained through solution treatment and aging; the titanium alloy is Ti-6Al-4V, and the material has the advantages of small specific gravity, light weight, and very good mechanical property and corrosion resistance.

Preferably, the rotation speed of the roller in the step (2) is 15-30 rpm.

Preferably, the step (3) is vacuumized until the vacuum degree reaches 10-50 Pa.

Preferably, the working pressure of the nitriding furnace after nitrogen is introduced into the nitriding furnace in the step (3) is 0.01-0.1 Pa.

Preferably, in the step (4), the voltage of the direct current pulse high voltage is-500 to-1000V, and the current is 1 to 5A.

Preferably, a low temperature tempering treatment is required before cooling in step (5), and the tempering temperature is less than 100 ℃. The design can eliminate transient enhanced diffusion, and aims to activate impurities and eliminate implantation damage, and to electrically activate impurity atoms.

Preferably, the thickness of the titanium nitride film layer in the step (5) is 2-5 μm.

Compared with the prior art of coating and plating a wear-resistant layer on the surface of a roller by adopting a coating and plating technology, the roller surface modification method has the following beneficial effects that the roller surface modification method applies the ion permeation and ion implantation technology to the surface of the roller for lithium battery production for modification:

1. the invention can perform ion permeation and ion implantation to form a titanium nitride film layer at a lower temperature in a vacuum environment, the implantation temperature of the titanium nitride ion beam can be less than 100 ℃, the kinetic energy of the titanium nitride ion beam is converted into heat energy to heat the roller by bombarding the surface of the roller after the nitrogen ion is accelerated in a cathode fall region, thermal activation is not needed, and the method is also not needed to be performed in a high-temperature environment, so that the roller surface does not generate oxidation and decarburization phenomena, obvious size change is not generated, and the controllability of the external size and the surface smoothness of the roller is ensured.

2. The invention injects high-energy ions into the surface of the roller to cause a large amount of interstitial atoms, vacancies and dislocation, and permeates nitrogen and titanium elements into the surface of the roller, thereby changing the chemical components of the surface layer, strengthening the surface, and leading the surface to have high wear resistance, fatigue strength, corrosion resistance, burn resistance and the like.

3. The titanium nitride film layer and the roller substrate have no interface, are metallurgically bonded, have the bonding strength of more than 85N and good adhesiveness, and a new surface layer formed by a series of physical and chemical interactions is generated on the surface of the roller, so that the surface hardness is more than HRC69, and the peeling problem is avoided.

The roller obtained by the method has high surface hardness, low porosity, no peeling, excellent wear resistance, bonding strength and antirust capability, and nanometer-level precision, and does not need to be machined or subjected to surface heat treatment subsequently.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more concise and clear, the present invention is described with reference to the following specific examples, but the present invention is by no means limited to these examples. The following description is only a preferred embodiment of the present invention, and is only for the purpose of describing the present invention, and should not be construed as limiting the scope of the present invention. It should be understood that any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

The invention discloses a method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery, which comprises the following steps:

(1) pretreating the surface of a roller for producing a lithium battery;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, and assembling a titanium or titanium alloy target on a target tool;

(3) vacuumizing the nitriding furnace and introducing nitrogen;

(4) loading direct current pulse high voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, ionizing nitrogen, generating glow discharge by nitrogen-containing gas around the roller, and performing ion nitriding treatment;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to be less than 100 ℃, the energy is 70-120 kev, and the beam current is 5 ∞20mA at a dose of 1.0X 10¹⁷/cm²～3.5×10¹⁸/cm²And performing high-energy ion implantation treatment on the surface of the roller, and cooling to room temperature to form a titanium nitride film layer.

Preferably, the pretreatment in the step (1) is to polish the surface of a roller for lithium battery production, the surface roughness after polishing is 0.01-0.05 μm, then ultrasonic oscillation cleaning is carried out for 2-5 times by adopting an acetone solution or an ethanol solution, each cleaning is carried out for 15-30 minutes, and drying is carried out for later use.

Preferably, the material of the roller for producing the lithium battery in the step (1) is 9Cr2Mo, 9Cr3Mo, a hard aluminum alloy or a titanium alloy. The 9Cr2Mo material in the design is typical Cr2 series cold roll steel, and 9Cr3Mo is roll steel for satin steel; the hard aluminum alloy is Al-Cu-Mg alloy, Cu and Mg can form a strengthening phase, and higher strength and hardness can be obtained through solution treatment and aging; the titanium alloy is Ti-6Al-4V, and the material has the advantages of small specific gravity, light weight, and very good mechanical property and corrosion resistance.

Preferably, the rotation speed of the roller in the step (2) is 15-30 rpm.

Preferably, the step (3) is vacuumized until the vacuum degree reaches 10-50 Pa.

Preferably, the working pressure of the nitriding furnace after nitrogen is introduced into the nitriding furnace in the step (3) is 0.01-0.1 Pa.

Preferably, in the step (4), the voltage of the direct current pulse high voltage is-500 to-1000V, and the current is 1 to 5A.

Preferably, a low temperature tempering treatment is required before cooling in step (5), and the tempering temperature is less than 100 ℃. The design can eliminate transient enhanced diffusion, and aims to activate impurities and eliminate implantation damage, and to electrically activate impurity atoms.

Preferably, the thickness of the titanium nitride film layer in the step (5) is 2-5 μm.

In the preparation process of the invention, a metal workpiece (roller) is placed in a furnace which is vacuumized and contains nitrogen gas, the metal workpiece placed in the furnace is used as a cathode and an anode (furnace body), direct-current high-voltage electricity is added between the metal workpiece and the anode (furnace body), so that the gas in the furnace discharges, a high-voltage electric field is generated in the discharging process, the introduced titanium nitride airflow impacts the cathode surface (workpiece surface) under the action of the high-voltage electric field between the workpiece surface and the furnace body, the titanium nitride impacts the workpiece surface at a fast speed in the movement process of the titanium nitride, kinetic energy is generated in the impacting process, the kinetic energy is converted into heat energy when impacting the workpiece surface, a large amount of heat energy can be generated on the workpiece surface, so that the workpiece surface is heated to the required temperature, titanium nitride molecules are decomposed into ions in the process, and the ions decomposed from the titanium nitride are absorbed by the workpiece surface when the workpiece is heated to the required temperature, and forming a titanium nitride film layer.

Example 1

A method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery comprises the following steps:

(1) the method comprises the following steps of pretreating the surface of a roller for lithium battery production made of 9Cr2Mo, wherein the pretreatment at least comprises polishing the surface of the roller for lithium battery production, the surface roughness after polishing is 0.01 mu m, then carrying out ultrasonic oscillation cleaning for 5 times by using an acetone solution, cleaning for 15 minutes each time, and drying for later use by using a fan;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, adjusting the autorotation speed of the roller to be 30 revolutions per minute, and assembling a titanium target on a target tool;

(3) vacuumizing the nitriding furnace until the vacuum degree reaches 50Pa, then introducing nitrogen, and keeping the working pressure at 0.1Pa after introducing the nitrogen;

(4) loading direct current pulse high voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, wherein the voltage is-1000V, the current is 5A, nitrogen is ionized, nitrogen-containing gas around the roller generates glow discharge, and ion nitriding treatment is carried out;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to 90 ℃, the energy is adjusted to 120kev, the beam current is 20mA, and the dosage is adjusted to 3.5 multiplied by 10¹⁸/m²Performing high-energy ion implantation treatment on the surface of the roller, and performing low-temperature tempering treatment at the tempering temperature of 6And cooling to room temperature at 0 ℃ to form the titanium nitride film layer.

In the embodiment, the thickness of the titanium nitride film layer prepared on the surface of the roller for producing the lithium battery is 5 microns through inspection, the bonding force with the roller is 95N, the surface hardness of the roller is HRC74, and the friction coefficient is less than 0.06.

Example 2

A method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery comprises the following steps:

(1) the method comprises the following steps of pretreating the surface of a roller for lithium battery production made of 9Cr3Mo, wherein the pretreatment at least comprises polishing the surface of the roller for lithium battery production, the surface roughness after polishing is 0.05 mu m, then carrying out ultrasonic oscillation cleaning for 2 times by adopting ethanol solution, cleaning for 30 minutes each time, and drying for later use;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, adjusting the autorotation speed of the roller to 15 revolutions per minute, and assembling a titanium alloy target on a target tool;

(3) vacuumizing the nitriding furnace until the vacuum degree reaches 10Pa, then introducing nitrogen, and keeping the working pressure at 0.01Pa after introducing the nitrogen;

(4) loading direct current pulse high voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, wherein the voltage is-500V, the current is 1A, nitrogen is ionized, nitrogen-containing gas around the roller generates glow discharge, and ion nitriding treatment is carried out;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to be 50 ℃, the energy is adjusted to be 70kev, the beam current is 5mA, and the dosage is 1.5 multiplied by 10¹⁷/m²And performing high-energy ion implantation treatment on the surface of the roller, performing low-temperature tempering treatment at the tempering temperature of less than 40 ℃, and cooling to room temperature to form a titanium nitride film layer.

In the embodiment, the thickness of the titanium nitride film layer prepared on the surface of the roller for producing the lithium battery is 2 microns through inspection, the bonding force with the roller is 85N, the surface hardness of the roller is HRC69, and the friction coefficient is less than 0.15.

Example 3

A method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery comprises the following steps:

(1) the method comprises the following steps of pretreating the surface of a roller for lithium battery production made of titanium alloy, wherein the pretreatment at least comprises polishing the surface of the roller for lithium battery production, the surface roughness after polishing is 0.03 mu m, then, ultrasonic oscillation cleaning is carried out for 3 times by adopting acetone solution, each cleaning is carried out for 20 minutes, and the roller is dried for later use;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, adjusting the autorotation speed of the roller to 25 revolutions per minute, and assembling a titanium alloy target on a target tool;

(3) vacuumizing the nitriding furnace until the vacuum degree reaches 30Pa, then introducing nitrogen, and keeping the working pressure at 0.05Pa after introducing the nitrogen;

(4) loading direct-current pulse high-voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, wherein the voltage is-800V, the current is 3A, nitrogen is ionized, nitrogen-containing gas around the roller generates glow discharge, and ion nitriding treatment is carried out;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to 70 ℃, the energy is 100kev, the beam current is 10mA, and the dosage is 1.0 multiplied by 10¹⁸/m²And performing high-energy ion implantation treatment on the surface of the roller, performing low-temperature tempering treatment at the tempering temperature of less than 60 ℃, and cooling to room temperature to form a titanium nitride film layer.

In the embodiment, the thickness of the titanium nitride film layer prepared on the surface of the roller for producing the lithium battery is 3 microns through inspection, the bonding force with the roller is 92N, the surface hardness of the roller is HRC72, and the friction coefficient is less than 0.1.

Example 4

A method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery comprises the following steps:

(1) the method comprises the following steps of pretreating the surface of a lithium battery production roller made of a duralumin alloy, wherein the pretreatment at least comprises polishing the surface of the lithium battery production roller, the surface roughness after polishing is 0.02 mu m, then carrying out ultrasonic oscillation cleaning for 4 times by adopting an ethanol solution, cleaning for 25 minutes each time, and drying for later use;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, adjusting the autorotation speed of the roller to be 20 revolutions per minute, and assembling a titanium target on a target tool;

(3) vacuumizing the nitriding furnace until the vacuum degree reaches 40Pa, then introducing nitrogen, and keeping the working pressure at 0.08Pa after introducing the nitrogen;

(4) loading direct current pulse high voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, wherein the voltage is-700V, the current is 2A, nitrogen is ionized, nitrogen-containing gas around the roller generates glow discharge, and ion nitriding treatment is carried out;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to be 60 ℃, the energy is adjusted to be 90kev, the beam current is 25mA, and the dosage is 4.0 multiplied by 10¹⁷/m²And performing high-energy ion implantation treatment on the surface of the roller, and performing low-temperature tempering treatment at 50 ℃, and cooling to room temperature to form a titanium nitride film layer.

In the embodiment, the thickness of the titanium nitride film layer prepared on the surface of the roller for producing the lithium battery is 4 microns, the bonding force with the roller is 90N, the surface hardness of the roller is HRC70, and the friction coefficient is less than 0.09.

Example 5

A method for preparing a titanium nitride film layer on the surface of a roller for producing a lithium battery comprises the following steps:

(1) the method comprises the following steps of pretreating the surface of a lithium battery production roller made of a duralumin alloy, wherein the pretreatment at least comprises polishing the surface of the lithium battery production roller, the surface roughness after polishing is 0.03 mu m, then carrying out ultrasonic oscillation cleaning for 3 times by adopting an ethanol solution, cleaning for 20 minutes each time, and drying for later use;

(2) fixing the pretreated roller on a workpiece table in a nitriding furnace for autorotation, adjusting the autorotation speed of the roller to 10 revolutions per minute, and assembling a titanium target on a target tool;

(3) vacuumizing the nitriding furnace until the vacuum degree reaches 20Pa, then introducing nitrogen, and keeping the working pressure at 0.03Pa after introducing the nitrogen;

(4) loading direct-current pulse high-voltage electricity between the roller and the nitriding furnace for electrifying by taking the roller as a cathode and the nitriding furnace as an anode, wherein the voltage is-600V, the current is 4A, nitrogen is ionized, nitrogen-containing gas around the roller generates glow discharge, and ion nitriding treatment is carried out;

(5) after the ion nitriding treatment, titanium nitride ion beams are injected into the nitriding furnace through an ion source, the injection temperature of the titanium nitride ion beams is adjusted to 80 ℃, the energy is 110kev, the beam current is 15mA, and the dosage is 2.5 multiplied by 10¹⁸/m²And performing high-energy ion implantation treatment on the surface of the roller, performing low-temperature tempering treatment at 65 ℃, and cooling to room temperature to form a titanium nitride film layer.

In the embodiment, the thickness of the titanium nitride film layer prepared on the surface of the roller for producing the lithium battery is 4 microns, the bonding force with the roller is 94N, the surface hardness of the roller is HRC73, and the friction coefficient is less than 0.11.

According to the invention, after the titanium nitride film layer is prepared on the surface of the roller for lithium battery production, the bonding strength and hardness of the surface of the roller can be obviously improved, the hardness and friction coefficient of the surface of the roller are related to the type, dosage and energy of implanted ions, the bonding strength and hardness of the surface of the roller are increased along with the increase of the implanted dosage and energy, the distribution uniformity is better, and the surface modification effect is better.

At present, after the titanium nitride film layer is prepared on the surface of the roller for producing the lithium battery by adopting the method, the roller is verified for many times by an industrial standard post company, and after the roller is normally produced and used for up to 252 kilometers in 5 months, the roller is detected to have no change in jumping, the thickness change of a pole piece is kept within 2 microns, the surface of the pole piece has no color difference, the roller with the prepared titanium nitride film layer is kept in faint yellow, the surface color has no change, the wear of the titanium nitride film layer is small, and the thickness difference of the pole piece rolled out has no change.

While the foregoing is directed to the preferred embodiment of the present invention, it will be appreciated that numerous modifications and variations may be devised by those skilled in the art in light of the above teachings. Therefore, the technical field of the invention based on the concept of the invention through logic analysis, reasoning or limited experiments of equivalent changes, modifications, substitutions and variations, should be determined by the claims scope of protection.