Arc-assisted plasma nitriding device

Abstract

The utility model belongs to the technical field of plasma nitriding, and particularly relates to an arc-assisted plasma nitriding device which comprises a vacuum furnace body, the vacuum furnace body is communicated with a nitrogen source through a gas pipe, and a heating part is arranged on the side wall of the vacuum furnace body; the arc power supply is connected with an electrode, and the electrode is arranged in the vacuum furnace body and used for generating an electric arc in the vacuum furnace body; the positive electrode of the negative bias power supply is used for being connected with the vacuum furnace body, and the negative electrode of the negative bias power supply is used for being connected with a sample and used for forming a negative bias electric field between the vacuum furnace body and the sample. According to the device, nitrogen ionization is improved by utilizing the auxiliary effect of the electric arc, a nitriding layer structure with high hardness and excellent wear resistance is obtained, and high-precision and high-efficiency nitriding of the thin-wall part is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of plasma nitriding, and in particular relates to an arc-assisted plasma nitriding device. Background Art

[0002] Plasma nitriding has been widely used for surface strengthening treatment of gears, transmission shafts, molds, etc., and the nitriding temperature is usually between 510 and 590°C. The low temperature leads to extremely low nitriding efficiency and poor industrial application value. In recent years, the surface strengthening treatment of thin-walled parts has posed a challenge to the existing plasma nitriding technology, such as fuel cell bipolar plates, valve plates, etc. Because under traditional processes, thin-walled parts are easy to deform, the nitriding layer is thin, and the hardness and wear resistance are poor. The traditional plasma nitriding device is based on the glow discharge theory, which realizes gas breakdown and ionization under high voltage, so the ionization rate is low, the concentration of active nitrogen atoms is low, and the nitriding efficiency is poor. Therefore, an arc-assisted plasma nitriding device is urgently needed to solve the problem. Utility Model Content

[0003] The utility model aims to provide an arc-assisted plasma nitriding device to solve the above problems.

[0004] To achieve the above purpose, the utility model provides the following solutions:

[0005] An arc-assisted plasma nitriding device, comprising:

[0006] A vacuum furnace body; the vacuum furnace body is connected to a nitrogen source through an air pipe, and a heating part is provided on a side wall of the vacuum furnace body;

[0007] An arc power supply, the arc power supply is connected to an electrode, the electrode is arranged in the vacuum furnace body, and is used to generate an arc in the vacuum furnace body;

[0008] A negative bias power supply, wherein the positive electrode of the negative bias power supply is used to be connected to the vacuum furnace body, and the negative electrode of the negative bias power supply is used to be connected to the sample, so as to form a negative bias electric field between the vacuum furnace body and the sample.

[0009] Preferably, the electrode comprises a first cylindrical target and a second cylindrical target, the positive electrode of the arc power supply is electrically connected to the first cylindrical target, and the negative electrode of the arc power supply is electrically connected to the second cylindrical target;

[0010] There are a plurality of the first cylindrical targets and the second cylindrical targets, a plurality of the first cylindrical targets and a plurality of the second cylindrical targets are arranged around the vacuum furnace body, and the first cylindrical targets and the second cylindrical targets are arranged at intervals;

[0011] The first cylindrical target outer shell is provided with a shielding portion.

[0012] Preferably, the shielding portion includes a baffle, which is arc-shaped and shields the outer side of the corresponding first cylindrical target. One end of the baffle is fixedly connected to the inner wall of the vacuum furnace body, and a gap is provided between the other end of the baffle and the inner wall of the vacuum furnace body.

[0013] Preferably, the gap is 10 to 20 mm.

[0014] Preferably, a workbench is provided in the middle of the inner side of the vacuum furnace body, the workbench is electrically connected to the negative pole of the negative bias power supply, and a plurality of circumferentially arranged sample tables are provided on the top of the workbench, the sample tables are used to place the samples.

[0015] Preferably, the workbench is rotatably connected to the middle portion of the inner side of the vacuum furnace body.

[0016] Preferably, the sample stage is rotatably connected to the workbench.

[0017] Preferably, the heating part comprises a resistance wire, and the resistance wire is embedded on the inner wall of the vacuum furnace body.

[0018] Preferably, the power of the resistance wire is 3-5 kW.

[0019] Preferably, the cross-section of the vacuum furnace body is an octagonal structure.

[0020] Compared with the prior art, the utility model has the following advantages and technical effects:

[0021] When in use, the workpiece is placed in the vacuum furnace body, the vacuum furnace body is closed, the air pipe is closed, the vacuum furnace body is evacuated by a mechanical pump, a Roots pump or a molecular pump system, and then the heating part is started to heat the vacuum furnace body to a specified temperature. The temperature inside the vacuum furnace body is 0-600°C, and the vacuum degree is 10-3-10Pa. The arc power supply and the negative bias power supply are started, and nitrogen is introduced through the air pipe. An arc is generated in the vacuum furnace body by the arc power supply to obtain plasma (electrons, atoms, positive ions). The electrons move toward the positive electrode in a directional manner and move toward the sample under the action of the higher negative bias electric field generated by the negative bias power supply. The nitrogen introduced into the furnace reacts with the electrons to be ionized to form charged nitrogen ions. The charged nitrogen ions are adsorbed on the surface of the workpiece and penetrate into the substrate. The heating part is used to make the vacuum furnace body reach the set temperature to promote nitrogen penetration and improve the nitriding efficiency. This device breaks through the bottleneck problem of low nitriding efficiency at low temperature in traditional plasma nitriding, utilizes the auxiliary effect of electric arc to improve nitrogen ionization, obtains a nitriding layer structure with high hardness and excellent wear resistance, and realizes high-precision and efficient nitriding of thin-walled parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor:

[0023] Figure 1 It is a schematic diagram of the structure of the utility model;

[0024] Among them, 1. the first cylindrical target; 2. the second cylindrical target; 3. the baffle; 4. the workbench; 5. the sample stage; 6. the arc power supply; 7. the negative bias power supply; 8. the air pipe; 9. the resistance wire. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0027] Reference Figure 1 The utility model discloses an arc-assisted plasma nitriding device, comprising:

[0028] The vacuum furnace body is connected to a nitrogen source through an air pipe 8, and a heating portion is provided on the side wall of the vacuum furnace body;

[0029] An arc power supply 6, the arc power supply 6 is connected to an electrode, the electrode is arranged in the vacuum furnace body, and is used to generate an arc in the vacuum furnace body;

[0030] A negative bias power supply 7, wherein the positive electrode of the negative bias power supply 7 is connected to the vacuum furnace body, and the negative electrode of the negative bias power supply 7 is connected to the sample, so as to form a negative bias electric field between the vacuum furnace body and the sample.

[0031] When in use, place the workpiece in the vacuum furnace, close the vacuum furnace, close the air pipe 8, evacuate the vacuum furnace through a mechanical pump, Roots pump or molecular pump system, then start the heating unit to heat the vacuum furnace to a specified temperature. The temperature in the vacuum furnace is 0-600°C and the vacuum degree is 10 -3～10Pa, start the arc power supply 6 and the negative bias power supply 7, and introduce nitrogen through the gas pipe 8. The arc power supply 6 is used to generate an arc in the vacuum furnace body to obtain plasma (electrons, atoms, positive ions). The electrons move toward the positive electrode and move toward the sample under the action of the higher negative bias electric field generated by the negative bias power supply 7. The nitrogen introduced into the furnace reacts with the electrons and is ionized to form charged nitrogen ions. The charged nitrogen ions are adsorbed on the surface of the workpiece and penetrate into the matrix. The vacuum furnace body is made to reach the set temperature through the heating part to promote nitrogen penetration and improve nitriding efficiency. This device breaks through the bottleneck problem of low nitriding efficiency at low temperature in traditional plasma nitriding, uses the auxiliary effect of the arc to improve nitrogen ionization, obtains a high-hardness, excellent wear-resistant nitriding layer structure, and realizes high-precision and efficient nitriding of thin-walled parts.

[0032] In a further optimized solution, the electrodes include a first cylindrical target 1 and a second cylindrical target 2, the positive electrode of the arc power supply 6 is electrically connected to the first cylindrical target 1, and the negative electrode of the arc power supply 6 is electrically connected to the second cylindrical target 2;

[0033] There are a plurality of first cylindrical targets 1 and second cylindrical targets 2, a plurality of first cylindrical targets 1 and a plurality of second cylindrical targets 2 are arranged around the vacuum furnace body, and the first cylindrical targets 1 and the second cylindrical targets 2 are arranged at intervals;

[0034] A shielding portion is disposed on the outer cover of the first cylindrical target 1 .

[0035] According to a further optimized solution, the shielding portion includes a baffle 3, which is arc-shaped and shields the outer side of the corresponding first cylindrical target 1. One end of the baffle 3 is fixedly connected to the inner wall of the vacuum furnace body, and a gap is provided between the other end of the baffle 3 and the inner wall of the vacuum furnace body.

[0036] The positive pole of the arc power supply 6 is electrically connected to the first cylindrical target 1, and the negative pole of the arc power supply 6 is electrically connected to the second cylindrical target 2. Under the action of the arc power supply 6, the first cylindrical target 1 and the second cylindrical target 2 are gasified to generate plasma. The first cylindrical target 1 is shielded by the baffle 3, and the second cylindrical target 2 is connected to the negative pole of the arc power supply 6 and the negative pole is grounded, so that its potential is 0.

[0037] The baffle 3 is used to separate the first cylindrical target 1 from the workpiece to prevent the coating from being processed onto the surface of the first cylindrical target 1 during coating processing.

[0038] Under the action of the arc power supply 6, the first cylindrical target 1 is gasified as an anode and the plasma generated is blocked by the baffle 3. Under the action of the negative bias electric field, only particles with positive charge are drawn out from the gap between the baffle 3 and the side wall of the furnace body, and are moved toward the sample under the action of the negative bias electric field.

[0039] The solution was further optimized, with a gap of 10 to 20 mm.

[0040] To further optimize the solution, a workbench 4 is provided in the middle of the inner side of the vacuum furnace body, the workbench 4 is electrically connected to the negative pole of the negative bias power supply 7, and a plurality of circumferentially arranged sample tables 5 are provided on the top of the workbench 4, and the sample tables 5 are used to place samples.

[0041] The negative electrode of the negative bias power supply 7 is electrically connected to the workbench 4, so that the potential of the workbench 4 is 0 to -1200V.

[0042] The positive electrode of the negative bias power supply 7 is electrically connected to the vacuum furnace body, so that the potential of the vacuum furnace body is 0, and a negative bias electric field is formed between the inner wall of the vacuum furnace body and the workbench 4, which facilitates the generated positive ions to move toward the sample.

[0043] To further optimize the solution, the workbench 4 is rotatably connected to the middle part of the inner side of the vacuum furnace body.

[0044] According to a further optimized solution, the sample table 5 is rotatably connected to the workbench 4 .

[0045] According to a further optimized solution, the heating part comprises a resistance wire 9, and the resistance wire 9 is embedded in the inner wall of the vacuum furnace body.

[0046] According to the further optimization scheme, the power of the resistance wire 9 is 3-5kW.

[0047] According to the further optimization scheme, the cross section of the vacuum furnace body is an octagonal structure.

[0048] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0049] The embodiments described above are only descriptions of the preferred methods of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. An arc-assisted plasma nitriding device, characterized in that: include: Vacuum furnace body; The vacuum furnace body is connected to a nitrogen source via an air pipe (8), and a heating portion is provided on a side wall of the vacuum furnace body; An arc power supply (6), the arc power supply (6) being connected to an electrode, the electrode being arranged in the vacuum furnace body and being used to generate an electric arc in the vacuum furnace body; A negative bias power supply (7), wherein the positive electrode of the negative bias power supply (7) is used to be connected to the vacuum furnace body, and the negative electrode of the negative bias power supply (7) is used to be connected to the sample, so as to form a negative bias electric field between the vacuum furnace body and the sample.

2. The arc-assisted plasma nitriding device according to claim 1, characterized in that: The electrodes include a first cylindrical target (1) and a second cylindrical target (2), the positive electrode of the arc power supply (6) is electrically connected to the first cylindrical target (1), and the negative electrode of the arc power supply (6) is electrically connected to the second cylindrical target (2); There are a plurality of the first cylindrical targets (1) and the second cylindrical targets (2), a plurality of the first cylindrical targets (1) and a plurality of the second cylindrical targets (2) are arranged in a surrounding manner in the vacuum furnace body, and the first cylindrical targets (1) and the second cylindrical targets (2) are arranged at intervals; The outer shell of the first cylindrical target (1) is provided with a shielding portion.

3. The arc-assisted plasma nitriding device according to claim 2, characterized in that: The shielding portion comprises a baffle (3), the baffle (3) is arc-shaped, the baffle (3) shields the outer side of the corresponding first cylindrical target (1), one end of the baffle (3) is fixedly connected to the inner wall of the vacuum furnace body, and a gap is provided between the other end of the baffle (3) and the inner wall of the vacuum furnace body.

4. The arc-assisted plasma nitriding device according to claim 3, characterized in that: The gap is 10 to 20 mm.

5. The arc-assisted plasma nitriding device according to claim 1, characterized in that: A workbench (4) is arranged in the middle of the inner side of the vacuum furnace body, the workbench (4) is electrically connected to the negative pole of the negative bias power supply (7), and a plurality of sample tables (5) arranged in an annular direction are arranged on the top of the workbench (4), and the sample tables (5) are used to place the samples.

6. The arc-assisted plasma nitriding device according to claim 5, characterized in that: The workbench (4) is rotatably connected to the middle part of the inner side of the vacuum furnace body.

7. The arc-assisted plasma nitriding device according to claim 5, characterized in that: The sample table (5) is rotatably connected to the workbench (4).

8. The arc-assisted plasma nitriding device according to claim 1, characterized in that: The heating part comprises a resistance wire (9), and the resistance wire (9) is embedded on the inner wall of the vacuum furnace body.

9. The arc-assisted plasma nitriding device according to claim 8, characterized in that: The power of the resistance wire (9) is 3-5 kW.

10. The arc-assisted plasma nitriding device according to claim 1, characterized in that: The cross section of the vacuum furnace body is an octagonal structure.

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