Method for low temperature ion nitriding and applications thereof

Abstract

The application discloses a low-temperature ion nitriding method and application. The low-temperature ion nitriding method comprises the following steps: under a selected temperature condition, ion etching treatment is performed on the surface of a workpiece by adopting an arc-enhanced glow discharge process, and then plasma nitriding treatment is performed on the workpiece by adopting an arc-enhanced plasma process to obtain a nitriding workpiece; wherein, a positive and negative alternating voltage is applied to the workpiece in the arc-enhanced plasma process. The low-temperature ion nitriding method provided by the application can realize nitriding at a lower temperature, effectively improves the deformation degree of the workpiece, and is widely applicable to surface strengthening of cutters, molds and metal parts.

Description

Technical Field

[0001] This invention belongs to the field of material surface processing, specifically relating to a method and application of low-temperature ion nitriding. Background Technology

[0002] Nitriding is an important chemical heat treatment technique that can significantly improve the surface hardness and wear resistance of metallic materials. Nitriding methods are generally classified into gas nitriding, liquid nitriding, solid nitriding, and ion nitriding, among which ion nitriding is widely used due to its advantages such as high efficiency, low pollution, easy control, and minimal workpiece deformation.

[0003] Currently, ion nitriding technology is widely used for surface hardening of products such as gears, traditional shafts, and molds. However, traditional ion nitriding typically involves high temperatures (450–590℃) and requires gas pressures of 100–500 Pa within the vacuum chamber. These high temperatures can lead to workpiece deformation and make precision control difficult; the high pressure within the furnace is necessary to achieve higher ion concentrations and ensure nitriding efficiency. Furthermore, traditional nitriding technology has extremely low efficiency at low temperatures, making it difficult to obtain a high-hardness nitrided layer, especially on titanium alloy substrates, where nitriding is almost impossible. Therefore, achieving ion nitriding at low temperatures is crucial for the development of nitriding technology. Summary of the Invention

[0004] The main objective of this invention is to provide a method and application for low-temperature ion nitriding, in order to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] One aspect of the present invention provides a method for low-temperature ion nitriding, comprising: performing ion etching on the surface of a workpiece using an arc-enhanced glow discharge process under selected temperature conditions, and then performing plasma nitriding on the workpiece using an arc-enhanced plasma process to obtain a nitrided workpiece; wherein, in the arc-enhanced plasma process, a positive and negative alternating voltage is applied to the workpiece.

[0007] Another aspect of the present invention provides a nitrided workpiece prepared by the aforementioned low-temperature ion nitriding method, wherein the surface hardness is 1200 HV. 0.2 above.

[0008] Compared with the prior art, the present invention has at least the following advantages:

[0009] The method provided by this invention utilizes low temperature to control the degree of deformation on the product surface, employs arc-enhanced plasma technology to promote gas ionization and obtain a high nitrogen ion concentration, applies a bipolar pulse bias voltage to the workpiece, where the positive electric field attracts thermionic electrons, and the workpiece surface is locally preheated by pulsed Joule heating, while the sputtering effect of the high-voltage negative electric field introduces high-density defects on the workpiece surface, increasing the diffusion rate of active nitrogen atoms. Based on the synergistic combination of multiple technologies and nitriding process parameters, in addition to further improving nitriding efficiency, a more ideal nitrided layer structure can be obtained, the product deformation degree can be controlled, and mechanical properties can be strengthened, thereby ensuring the product's service performance. The method provided by this invention requires a low process temperature, which has great application prospects for products with extremely high deformation requirements, while reducing energy consumption caused by macroscopic overall heating. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the device structure for low-temperature ion nitriding in a typical embodiment of the present invention;

[0012] Figure 2 This is a schematic diagram of the positive and negative alternating voltage waveform output by the bipolar pulse power supply in a typical embodiment of the present invention;

[0013] Figure 3 This is a metallographic micrograph of the M2 high-speed steel sheet in Embodiment 1 of the present invention;

[0014] Figure 4 This is a metallographic micrograph of the M2 high-speed steel sheet in Embodiment 2 of the present invention;

[0015] Figure 5 This is a metallographic micrograph of the M2 high-speed steel sheet in Embodiment 3 of the present invention;

[0016] Figure 6 This is a metallographic micrograph of the M2 high-speed steel sheet in Embodiment 4 of the present invention;

[0017] Figure 7 This is a metallographic micrograph of the M2 high-speed steel sheet in Comparative Example 1 of this invention.

[0018] Reference numerals: 1-vacuum chamber, 2-workpiece holder, 3-heating tube, 4-arc target, 5-baffle, 6-auxiliary anode, 7-bipolar pulse power supply. Detailed Implementation

[0019] The invention will be more fully understood by reading the following detailed description. However, it should be understood that the detailed description disclosed below is merely exemplary of the invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as a representative basis for teaching those skilled in the art to employ the invention in different ways in any suitable detailed embodiment.

[0020] As one aspect of the technical solution of the present invention, a method for low-temperature ion nitriding includes: performing ion etching on the surface of a workpiece using an arc-enhanced glow discharge process under selected temperature conditions, and then performing plasma nitriding on the workpiece using an arc-enhanced plasma process to obtain a nitrided workpiece; wherein, in the arc-enhanced plasma process, a positive and negative alternating voltage is applied to the workpiece.

[0021] In some embodiments, the low-temperature ion nitriding method includes: placing the workpiece in a reaction chamber, evacuating the reaction chamber to a background vacuum, heating it to a selected temperature, and then performing the ion etching process.

[0022] In this invention, the ion etching process can be argon ion etching, but is not limited to argon ions. Inert gas ion (argon, krypton, etc.) or mixed reducing gas ion (hydrogen) etching can also be used. This step mainly cleans the workpiece surface and removes contaminants and oxide layers on the workpiece surface so that nitrogen ions can penetrate smoothly in the future. Considering the cost-effectiveness in industry, argon ions or argon ions plus hydrogen ions are the most suitable.

[0023] In this invention, the argon ion etching refers to arc-enhanced glow discharge technology. Arc-enhanced glow discharge technology generates high-density electrons through arc discharge. The electrons are attracted by the auxiliary anode, detach from the target area, collide with the introduced gas, and ionize into gas ions. The negative voltage on the workpiece attracts the gas ions and bombards its surface. The arc target can be a metal target such as Ti or Cr, or an alloy target such as TiAl.

[0024] In some preferred embodiments, the selected temperature is 100°C-400°C.

[0025] In some preferred embodiments, the gas pressure in the reaction chamber is 1-10 Pa.

[0026] In some preferred embodiments, the heating method includes heating with an infrared electric heating tube.

[0027] In some implementations, the ion etching process takes 10-60 minutes.

[0028] In some implementations, the arc-enhanced glow discharge process includes: connecting the auxiliary anode to the positive terminal of a DC power supply, connecting the workpiece to the output terminal of a pulse power supply to output a negative voltage, igniting an arc with an arc target, and introducing argon gas.

[0029] In some preferred embodiments, the arc-enhanced glow discharge process employs a bipolar pulse power supply with a negative voltage of 200-1200V, a pulse frequency of 80-10kHz, and a duty cycle of 0.2-1.0.

[0030] In some preferred embodiments, the flow rate of the argon gas in the arc-enhanced glow discharge process is 100-200 sccm.

[0031] In some implementations, the arc-enhanced plasma process includes: connecting an auxiliary anode to the positive terminal of a DC power supply, connecting the workpiece to the output terminal of a bipolar pulse power supply to output alternating positive and negative voltages, igniting an arc with an arc target, and introducing nitrogen, hydrogen, and argon gases.

[0032] In some preferred embodiments, in the arc-enhanced plasma process, the flow rate of nitrogen is 50-200 sccm, the flow rate of hydrogen is 50-100 sccm, and the flow rate of argon is 50-200 sccm.

[0033] In some preferred embodiments, in the arc-enhanced plasma process, the parameters of the alternating positive and negative voltages are: positive voltage 20-200V, pulse width 40μs-1000μs; negative voltage 200-1200V, pulse width 40μs-1000μs; positive and negative pulse interval 20μs-500μs; pulse frequency 80-10kHz; and duty cycle 0.2-1.0. Traditional ion nitriding primarily focuses on ion density and negative bias voltage of the matrix (attracting nitrogen ion bombardment). Since plasma is electrically neutral, it also contains a large number of electrons. This invention guides electrons with positive pulses to locally Joule heat the matrix, thereby achieving macroscopic low temperature.

[0034] In some preferred embodiments, the arc target may be any one or a combination of two or more of Ti target, Cr target, and TiAl target.

[0035] In some preferred embodiments, the current of the arc target is 40-100A.

[0036] In some preferred embodiments, the current of the DC power supply is 20-80A.

[0037] In some preferred embodiments, the auxiliary anode is columnar or planar, with a height greater than or equal to the overall height of the workpiece.

[0038] In some embodiments, the plasma nitriding treatment takes 60-180 minutes.

[0039] In some embodiments, the low-temperature ion nitriding method further includes: after plasma nitriding the workpiece, cooling it to below 100°C under vacuum to obtain the nitrided workpiece.

[0040] In some more specific implementations, the low-temperature ion nitriding method includes the following steps:

[0041] 1) Clean and dry the workpiece, place it in the vacuum chamber, turn on the mechanical pump and molecular turbine pump in sequence to evacuate to the background vacuum, heat to 100℃-400℃, and remove the residue in the vacuum chamber.

[0042] 2) Maintain the temperature inside the vacuum chamber at 100℃-400℃. When the vacuum level of the chamber is lower than 2.0×10⁻⁶, -2 pa, introduce high-purity argon gas to maintain the vacuum chamber pressure at 1-10Pa, keep the arc target current at 40-100A constant, close the baffle, connect the auxiliary anode to the positive terminal of the DC power supply, set the current to 20-80A, connect the workpiece to the output terminal of the bipolar pulse power supply, output negative voltage, and perform argon ion etching on the workpiece surface for 10-60 minutes.

[0043] 3) Continuously introduce high-purity nitrogen, high-purity hydrogen and high-purity argon into the vacuum chamber, maintain the temperature in the vacuum chamber at 100-400℃ and the pressure in the vacuum chamber at 1-10Pa, connect the workpiece to the output terminal of the bipolar pulse power supply, output positive and negative alternating voltage, keep the arc target current at 40-100A constant, close the baffle, connect the auxiliary anode to the positive terminal of the DC power supply, set the current to 20-80A, and perform plasma nitriding for 60-180min;

[0044] 4) The workpiece is then cooled to below 100°C under vacuum, the vacuum chamber is opened and the workpiece is removed.

[0045] As another aspect of the technical solution of the present invention, the surface hardness of the nitrided workpiece prepared by the aforementioned low-temperature ion nitriding method is 1200 HV. 0.2 above.

[0046] In summary, the low-temperature ion nitriding method provided by this invention can achieve nitriding at relatively low temperatures (100℃~400℃). It utilizes a cathode arc and an auxiliary anode to ionize nitrogen atoms, and performs ion nitriding on the substrate surface through a bipolar pulse bias. This invention controls the degree of deformation on the product surface through low temperature, utilizes arc-enhanced plasma technology to obtain high-density plasma, promotes gas ionization, and applies a bipolar pulse bias to the workpiece. The positive electric field attracts thermionic electrons, and the workpiece surface is locally preheated through pulsed Joule heating. Meanwhile, the sputtering effect of the high-voltage negative electric field introduces high-density defects on the workpiece surface, increasing the diffusion rate of active nitrogen atoms. The nitriding method provided by this invention solves the problem of easy workpiece deformation during traditional ion nitriding, achieving efficient ion nitriding while ensuring minimal or near-zero workpiece deformation, guaranteeing the dimensional accuracy requirements of the product. It is suitable for surface strengthening of cutting tools, molds, and metal parts.

[0047] The present invention is further illustrated below by way of examples, but the invention is not limited to the scope of the examples described. All reagents and raw materials used in the following examples are commercially available, and test methods not specifically specified are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0048] Example 1

[0049] In this embodiment, the following is adopted: Figure 1 The apparatus shown involves cleaning and drying an M2 high-speed steel sheet, placing it on a workpiece holder 2 within a vacuum chamber 1, evacuating to a baseline vacuum, turning on the heating tube 3 to heat to 100°C, and maintaining the temperature inside the vacuum chamber at 100°C. When the vacuum level of the chamber drops below 2.0 × 10⁻⁶... -2 High-purity argon gas (flow rate 100 sccm) was introduced to maintain a vacuum chamber pressure of 10 Pa. The current of the titanium target 4 arc target was set to 100 A, the baffle 5 was closed, the auxiliary anode 6 was connected to the positive terminal of the DC power supply and the current was set to 60 A, the workpiece holder 2 was connected to the output terminal of the bipolar pulse power supply 7 with an output voltage of -300 V, a pulse frequency of 1 kHz, and a duty cycle of 0.8. Argon ion etching was performed on the surface of the M2 high-speed steel sheet for 30 min.

[0050] Subsequently, high-purity nitrogen, high-purity hydrogen, and high-purity argon are continuously introduced into vacuum chamber 1 (nitrogen flow rate 50 sccm, hydrogen flow rate 50 sccm, argon flow rate 200 sccm), maintaining the temperature inside the vacuum chamber at 100℃ and the pressure inside the vacuum chamber at 10Pa. The workpiece holder 2 is connected to the output terminal of bipolar pulse power supply 7, outputting alternating positive and negative voltages. A voltage waveform diagram is shown below. Figure 2As shown, the positive voltage is 100V, the pulse width is 600μs, the negative voltage is 400V, the pulse width is 100μs, the positive and negative pulse interval is 50μs, the pulse frequency is 1kHz, the duty cycle is 0.8, the current of the titanium target 4 arc target is kept constant at 100A, the baffle 5 is closed, the auxiliary anode 6 is connected to the positive terminal of the DC power supply, the current is set to 60A, and plasma nitriding is performed for 120min.

[0051] Finally, after the M2 high-speed steel has cooled to below 100°C under vacuum, open vacuum chamber 2 and remove the M2 high-speed steel.

[0052] Please see Figure 3 The image shows a metallographic micrograph of the M2 high-speed steel sheet in this embodiment. After ion nitriding, the nitriding depth is between 45-50 μm, there is no white bright layer, and the surface hardness is 1375 HV. 0.2 .

[0053] Example 2

[0054] In this embodiment, the following is adopted: Figure 1 The apparatus shown involves cleaning and drying an M2 high-speed steel sheet, placing it on a workpiece holder 2 within a vacuum chamber 1, evacuating to a baseline vacuum, turning on the heating tube 3 to heat to 100°C, and maintaining the temperature inside the vacuum chamber at 100°C. When the vacuum level of the chamber drops below 2.0 × 10⁻⁶... -2 High-purity argon gas (flow rate 200 sccm) was introduced to maintain a vacuum chamber pressure of 10 Pa. The current of the arc target 4 (chromium target) was set to 100 A, the baffle 5 was closed, the auxiliary anode 6 was connected to the positive terminal of the DC power supply, and the current was set to 60 A. The workpiece holder 2 was connected to the output terminal of the bipolar pulse power supply 7, with an output voltage of -500 V, a pulse frequency of 1 kHz, and a duty cycle of 0.6. Argon ion etching was performed on the surface of the M2 high-speed steel sheet for 60 min.

[0055] Subsequently, high-purity nitrogen, high-purity hydrogen, and high-purity argon are continuously introduced into vacuum chamber 1 (nitrogen flow rate 200 sccm, hydrogen flow rate 100 sccm, argon flow rate 100 sccm), maintaining the temperature inside the vacuum chamber at 300℃ and the vacuum chamber pressure at 5 Pa. The workpiece holder 2 is connected to the output terminal of bipolar pulse power supply 7, outputting alternating positive and negative voltages. A voltage waveform diagram is shown below. Figure 2 As shown, the positive voltage is 200V, the pulse width is 600μs, the negative voltage is 300V, the pulse width is 800μs, the positive and negative pulse interval is 200μs, the pulse frequency is 200Hz, the duty cycle is 0.6, the current of the arc target 4 chromium target is kept constant at 80A, the baffle 5 is closed, the auxiliary anode 6 is connected to the positive terminal of the DC power supply, the current is set to 40A, and plasma nitriding is performed for 180min.

[0056] Finally, after the M2 high-speed steel has cooled to below 100°C under vacuum, open vacuum chamber 2 and remove the M2 high-speed steel.

[0057] Please see Figure 4 The image shows a metallographic micrograph of the M2 high-speed steel sheet in this embodiment. After ion nitriding, the nitriding depth is between 65-70 μm, there is no white bright layer, and the surface hardness is 1513 HV. 0.2 .

[0058] Example 3

[0059] In this embodiment, the following is adopted: Figure 1 The apparatus shown involves cleaning and drying an M2 high-speed steel sheet, placing it on a workpiece holder 2 within a vacuum chamber 1, evacuating to a baseline vacuum, turning on the heating tube 3 to heat to 400°C, and maintaining the temperature inside the vacuum chamber at 400°C. When the vacuum level of the chamber drops below 2.0 × 10⁻⁶... -2 High-purity argon gas (flow rate 150 sccm) was introduced to maintain a vacuum chamber pressure of 1 Pa. The current of the titanium target 4 arc target was set to 40 A, the baffle 5 was closed, the auxiliary anode 6 was connected to the positive terminal of the DC power supply, and the current was set to 20 A. The workpiece holder 2 was connected to the output terminal of the bipolar pulse power supply 7, with an output voltage of -1200 V, a pulse frequency of 80 Hz, and a duty cycle of 1.0. Argon ion etching was performed on the surface of the M2 high-speed steel sheet for 10 min.

[0060] Subsequently, high-purity nitrogen, high-purity hydrogen, and high-purity argon are continuously introduced into vacuum chamber 1 (nitrogen flow rate 100 sccm, hydrogen flow rate 70 sccm, and argon flow rate 50 sccm), maintaining the temperature inside the vacuum chamber at 400℃ and the vacuum chamber pressure at 1 Pa. The workpiece holder 2 is connected to the output terminal of bipolar pulse power supply 7, outputting alternating positive and negative voltages. A voltage waveform diagram is shown below. Figure 2 As shown, the positive voltage is 20V, the pulse width is 40μs, the negative voltage is 1200V, the pulse width is 40μs, the positive and negative pulse interval is 20μs, the pulse frequency is 10kHz, the duty cycle is 1.0, the current of the titanium target 4 arc target is 40A and kept constant, the baffle 5 is closed, the auxiliary anode 6 is connected to the positive terminal of the DC power supply, the current is set to 20A, and plasma nitriding is performed for 60min.

[0061] Finally, after the M2 high-speed steel has cooled to below 100°C under vacuum, open vacuum chamber 2 and remove the M2 high-speed steel.

[0062] Please see Figure 5 The image shows a metallographic micrograph of the M2 high-speed steel sheet in this embodiment. After ion nitriding, the nitriding depth is between 30-35 μm, there is no white bright layer, and the surface hardness is 1219 HV. 0.2 .

[0063] Example 4

[0064] In this embodiment, the following is adopted: Figure 1The apparatus shown involves cleaning and drying an M2 high-speed steel sheet, placing it on a workpiece holder 2 within a vacuum chamber 1, evacuating to a baseline vacuum, turning on the heating tube 3 to heat to 200°C, and maintaining the temperature inside the vacuum chamber at 200°C. When the vacuum level of the chamber drops below 2.0 × 10⁻⁶, the process continues. -2 High-purity argon gas (flow rate 120 sccm) was introduced to maintain a vacuum chamber pressure of 3 Pa. The current of the arc target 4 (titanium-aluminum target) was set to 80 A. The baffle 5 was closed. The auxiliary anode 6 was connected to the positive terminal of the DC power supply, and the current was set to 80 A. The workpiece holder 2 was connected to the output terminal of the bipolar pulse power supply 7, with an output voltage of -200 V, a pulse frequency of 10 kHz, and a duty cycle of 0.2. Argon ion etching was performed on the surface of the M2 high-speed steel sheet for 40 min.

[0065] Subsequently, high-purity nitrogen, high-purity hydrogen, and high-purity argon are continuously introduced into vacuum chamber 1 (nitrogen flow rate: 200 sccm, hydrogen flow rate: 100 sccm, argon flow rate: 200 sccm), maintaining the temperature inside the vacuum chamber at 200℃ and the vacuum chamber pressure at 3 Pa. The workpiece holder 2 is connected to the output terminal of bipolar pulse power supply 7, outputting alternating positive and negative voltages. A voltage waveform diagram is shown below. Figure 2 As shown, the positive voltage is 100V, the pulse width is 1000μs, the negative voltage is 200V, the pulse width is 1000μs, the positive and negative pulse interval is 500μs, the pulse frequency is 80Hz, the duty cycle is 0.2, the current of the arc target 4 titanium aluminum target is kept constant at 80A, the baffle 5 is closed, the auxiliary anode 6 is connected to the positive terminal of the DC power supply, the current is set to 80A, and plasma nitriding is performed for 150min.

[0066] Finally, after the M2 high-speed steel has cooled to below 100°C under vacuum, open vacuum chamber 2 and remove the M2 high-speed steel.

[0067] Please see Figure 6 The image shows a metallographic micrograph of the M2 high-speed steel sheet in this embodiment. After ion nitriding, the nitriding depth is between 70-80 μm, there is no white bright layer, and the surface hardness is 1462 HV. 0.2 .

[0068] Comparative Example 1

[0069] In this embodiment, the following is adopted: Figure 1 The apparatus shown involves cleaning and drying an M2 high-speed steel sheet, placing it on a workpiece holder 2 within a vacuum chamber 1, evacuating to a baseline vacuum, turning on the heating tube 3 to heat to 100°C, and maintaining the temperature inside the vacuum chamber at 100°C. When the vacuum level of the chamber drops below 2.0 × 10⁻⁶... -2High-purity argon gas (flow rate 100 sccm) was introduced to maintain a vacuum chamber pressure of 10 Pa. The current of the titanium target 4 arc target was set to 100 A, the baffle 5 was closed, the auxiliary anode 6 was connected to the positive terminal of the DC power supply and the current was set to 60 A, the workpiece holder 2 was connected to the output terminal of the bipolar pulse power supply 7 with an output voltage of -300 V, a pulse frequency of 1 kHz, and a duty cycle of 0.8. Argon ion etching was performed on the surface of the M2 high-speed steel sheet for 30 min.

[0070] Subsequently, high-purity nitrogen, high-purity hydrogen, and high-purity argon were continuously introduced into vacuum chamber 1 (nitrogen flow rate: 50 sccm, hydrogen flow rate: 50 sccm, argon flow rate: 200 sccm). The temperature inside the vacuum chamber was maintained at 100℃, and the vacuum chamber pressure was maintained at 10Pa. The workpiece holder 2 was connected to the output terminal of the bipolar pulse power supply 7, with an output voltage of -400V, a pulse width of 100μs, a pulse frequency of 1kHz, and a duty cycle of 0.1. The titanium target current of the arc target 4 was kept constant at 100A. The baffle 5 was closed, and the auxiliary anode 6 was connected to the positive terminal of the DC power supply with a current set to 60A. Plasma nitriding was performed for 120 minutes.

[0071] Finally, after the M2 high-speed steel has cooled to below 100°C under vacuum, open vacuum chamber 2 and remove the M2 high-speed steel.

[0072] Compared to Example 1, the workpiece in Comparative Example 1 was not subjected to a positive voltage, resulting in a lack of electron bombardment and the workpiece surface failing to reach the temperature required for nitriding. Please refer to... Figure 7 The image shows a metallographic micrograph of the M2 high-speed steel sheet used in this comparative example. After the aforementioned ion nitriding, the M2 high-speed steel has no nitrided layer, and its surface hardness is 850 HV. 0.2 It is comparable to M2 high-speed steel without ion nitriding.

[0073] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0074] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for low-temperature ion nitriding, characterized in that, include: Under conditions of 100℃-200℃, the workpiece surface is subjected to ion etching treatment for 10-60 min using an arc-enhanced glow discharge process, followed by plasma nitriding treatment for 60-180 min using an arc-enhanced plasma process to obtain a nitrided workpiece; wherein, in the arc-enhanced glow discharge process, a bipolar pulse power supply is used, with a negative voltage of 200-1200V, a pulse frequency of 80-10kHz, and a duty cycle of 0.2-1.0; In the arc-enhanced plasma process, a positive and negative alternating voltage is applied to the workpiece. The parameters of the positive and negative alternating voltage are as follows: positive voltage 20-200V, pulse width 40μs-1000μs; negative voltage 200-1200V, pulse width 40μs-1000μs; positive and negative pulse interval 20μs-500μs; pulse frequency 80-10kHz; and duty cycle 0.2-1.

0. The arc-enhanced glow discharge process includes: connecting the auxiliary anode to the positive terminal of a DC power supply, connecting the workpiece to the output terminal of a pulse power supply to output a negative voltage, igniting the arc target, and introducing argon gas. The arc-enhanced plasma process includes: connecting the auxiliary anode to the positive terminal of a DC power supply, connecting the workpiece to the output terminal of a bipolar pulse power supply to output alternating positive and negative voltages, igniting an arc with an arc target, and introducing nitrogen, hydrogen, and argon gases.

2. The method according to claim 1, characterized in that, include: The workpiece is placed in the reaction chamber, the reaction chamber is evacuated to a background vacuum, heated to a selected temperature, and then the ion etching process is performed.

3. The method according to claim 2, characterized in that, The gas pressure in the reaction chamber is 1-10 Pa.

4. The method according to claim 2, characterized in that, The heating method includes infrared electric heating tube heating.

5. The method according to claim 1, characterized in that, In the arc-enhanced glow discharge process, the flow rate of argon gas is 100-200 sccm.

6. The method according to claim 1, characterized in that, In the arc-enhanced plasma process, the flow rate of nitrogen is 50-200 sccm, the flow rate of hydrogen is 50-100 sccm, and the flow rate of argon is 50-200 sccm.

7. The method according to claim 1, characterized in that, The arc target is any one or a combination of two or more of Ti target, Cr target, and TiAl target.

8. The method according to claim 1, characterized in that, The current of the arc target is 40-100A.

9. The method according to claim 1, characterized in that, The DC power supply has a current of 20-80A.

10. The method according to claim 1, characterized in that, The auxiliary anode is columnar or planar, and its height is greater than or equal to the overall height of the workpiece.

11. The method according to claim 1, characterized in that, Also includes: After plasma nitriding treatment, the workpiece is cooled to below 100°C under vacuum to obtain a nitrided workpiece.

12. A nitrided workpiece prepared by the method according to any one of claims 1-11, characterized in that, The surface hardness of the nitrided workpiece is 1300 HV. 0.2 above.

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