CN116875936A - Uniform nitriding device for high-density plasma on surface of soft base material and working method - Google Patents

Abstract

The invention relates to the technical field of soft base material surface strengthening, in particular to a soft base material surface high-density plasma uniform nitriding device and a working method. The device comprises 4 arc sources respectively arranged at the left side, the right side, the front side and the rear side in a cavity, wherein a permanent magnet device is arranged at the rear of each arc source, each arc source is electrically connected with the negative electrode of one arc source power supply, and the positive electrode of the arc source power supply is grounded; the device also comprises 4 auxiliary anodes respectively arranged at four corners in the cavity; an electromagnetic coil is arranged behind each auxiliary anode; each auxiliary anode is electrically connected with the positive electrode of an auxiliary anode power supply through an adjustable resistor, and the negative electrode of the auxiliary anode power supply is grounded.

Description

High-density plasma uniform nitriding device and working method for the surface of soft base materials

Technical field

The invention relates to the technical field of surface strengthening of soft base materials. The specific field is a high-density plasma uniform nitriding device and working method on the surface of soft base materials.

Background technique

High-speed steel, stainless steel, etc. (soft base materials) are widely used in industrial production due to their excellent physical and mechanical properties, such as corrosion resistance, good plasticity and smoothness, etc. However, the hardness and wear resistance of high-speed steel and stainless steel materials are low. In harsh service environments, the inner surface will crack due to high-temperature oxidation, friction and corrosion, seriously affecting the service life and causing a large amount of economic losses. When faced with complex and harsh service environments, in order to obtain better overall performance, specific nitriding surface strengthening treatment is required to increase service life and ensure service safety.

At present, although the inner surface can be treated by electroplating and chemical plating, researchers in this field have been looking for a solution due to problems such as poor uniformity, less material deposited by electroplating, impact on the morphology of the inner surface, and environmental pollution. A better technical solution.

When depositing a coating on a relatively soft metal substrate, the relatively soft metal substrate is actually unable to support a thin hard coating, and plastic deformation will occur under high load, causing coating failure, resulting in the "eggshell effect" ” will reduce the load-bearing capacity of the coating surface, thereby limiting its working performance. Surface nitriding is recognized as an economical and effective treatment method to improve the hardness and wear resistance of stainless steel. After nitriding treatment, the surface of stainless steel will form a layer of supersaturated solid solution phase with high hardness, which will greatly improve the hardness and wear resistance of stainless steel. The hardness and wear resistance of the stainless steel surface extend the service life. Therefore, it is necessary to perform specific nitriding surface strengthening treatment on the soft base material, and then perform surface hard film coating treatment on it. This dual surface treatment is particularly effective in improving the surface load-bearing capacity of relatively soft substrates.

Among many nitriding technologies, in the large-scale industrial production of integrated nitriding and plating, there are often problems such as uneven nitriding, inability to accurately control the nitriding phase structure, and prone to sparking, edge effects, temperature rise effects, etc. on the surface of special-shaped substrates. Problems such as the inability to integrate infiltration plating and the electronic shielding effect caused by increased loading capacity make plasma nitriding unable to achieve stable production of large-size and large-volume parts in industrial production.

For example: CN115261777A discloses a device and method for optimizing ion nitriding of the inner wall of a tube. The device uses a multi-arc ion plating plasma source and is a multi-arc nitriding device. This type of device cannot avoid surface sparking of tip parts. , Problems such as the inability to adjust the plasma density area, the inability to achieve industrial large-scale loading and the uniformity of nitriding.

Contents of the invention

The object of the present invention is to provide a device and working method for high-density plasma uniform nitriding on the surface of soft base materials. The device can achieve an axially distributed adjustable magnetic field by coupling the magnetic field distribution of a PVD multi-arc ion source and an auxiliary anode. The mirror-ratio multi-level magnetic field realizes a scalable annular plasma with 360° lateral variable characteristic parameters, making it a true integration of penetration and plating.

In order to achieve the above objects, the present invention provides the following technical solutions:

A high-density plasma uniform nitriding device for the surface of soft base materials, including 4 arc sources respectively arranged on the left, right, front and rear sides of the chamber, with an arc source provided behind each arc source Permanent magnet device, each arc source is electrically connected to the negative pole of an arc source power supply, the positive pole of the arc source power supply is grounded; it also includes 4 auxiliary anodes respectively arranged at the four corners of the chamber; behind each auxiliary anode An electromagnetic coil is provided; each auxiliary anode is electrically connected to the positive pole of an auxiliary anode power supply through an adjustable resistor, and the negative pole of the auxiliary anode power supply is grounded.

Furthermore, the electromagnetic coil is adjustable and can be coupled with the magnetic field of the permanent magnet device to achieve a multi-level magnetic field with an adjustable magnetic mirror ratio distributed along the axial direction, thereby achieving 360° lateral variable characteristic parameters. The retractable annular plasma realizes uniform immersion plasma nitriding.

Furthermore, the arc source power supply connected to the arc source can adjust the current size. By adjusting the current size of the arc source power supply, the ability of the arc source to emit electrons is controlled, thereby controlling the density of plasma to regulate the composition and structure of the infiltrated software material. .

Furthermore, the auxiliary anode power supply connected to the auxiliary anode can adjust the current size. By adjusting the current size of the auxiliary anode power supply, the auxiliary anode is controlled to absorb the electrons generated by the arc source, thereby controlling the density of the plasma to regulate the density of the infiltrated software material. Composition and structure.

Furthermore, a turntable is provided in the middle of the chamber.

Furthermore, the soft base material to be infiltrated is loaded on the turntable.

Furthermore, the arc source power supply and the auxiliary anode power supply can be pulse power supplies or DC power supplies. The power supplies are adjustable. The positive electrode of the arc source and the negative electrode of the auxiliary anode are both connected to the vacuum chamber, and the vacuum chamber is grounded.

Furthermore, the current of the auxiliary anode can be adjusted through an adjustable resistor.

Further, each electromagnetic coil is electrically connected to a separate DC power supply.

The working method of the high-density plasma uniform nitriding device on the surface of soft base materials of the present invention is specifically as follows:

A large number of electrons evaporated from the arc source are pulled by the auxiliary anode in the chamber, and by adjusting the magnetic field distribution area coupled by the permanent magnet device and the electromagnetic coil, a large number of electrons perform spiral motion under the action of the electromagnetic field, filling the chamber for ionization of the incoming gas. atoms, so that the gas atoms form a plasma state and are injected and diffused into the soft base material of the infiltrated parts loaded on the turntable for nitriding; the auxiliary anode current is adjusted through the adjustable resistance to regulate the ability to absorb electrons to ensure that the electrons are ionized The plasma area extends and immerses the infiltrated soft base material to achieve precise control of the nitriding composition and structure;

Alternatively, by adjusting the position of the permanent magnet device to couple the magnetic field of the electromagnetic coil, a multi-level magnetic mirror field with an adjustable magnetic mirror ratio distributed along the circumference of the chamber can be realized for plasma nitriding work;

Alternatively, the electric field of the arc source coupled with the auxiliary anode can be adjusted to control the plasma density and energy, thereby completing the nitriding work of the soft base material to be infiltrated.

The technical principle of this device: A large number of electrons generated by the arc source are pulled by the anode in the chamber, and perform spiral motion under the magnetic enhancement device coupled with the permanent magnet device and the electromagnetic coil to fill the chamber, and ionize the gas atoms introduced, The gas atoms are injected into a plasma state and diffused inside the soft base material for nitriding.

Compared with the conventional multi-arc nitriding device, this device can not only control the distribution area of the coupling magnetic field by adjusting the current of the auxiliary anode electromagnetic coil, but also control the movement trajectory of a large number of electrons generated by the arc source under the action of the electromagnetic field, thereby Control the plasma density area to achieve uniform immersion plasma nitriding, thereby accurately controlling the nitriding composition and structure; at the same time, it can avoid the electronic shielding effect during industrial large-scale loading.

Compared with the prior art, the beneficial effects of the present invention are:

(1) This device achieves uniform discharge of the arc source structure of a large-area target (diameter 160mm), generates more electrons, and ionizes gas atoms.

(2) The device is based on the multi-arc ion source technology of magnetic mirror field scanning and large-area target arc source structure. By coupling the magnetic field distribution of the multi-arc ion source and the auxiliary anode, a multi-level adjustable magnetic mirror ratio distributed along the axial direction is obtained. Magnetic field realizes 360° lateral variable characteristic parameters of scalable annular plasma, achieving uniform immersion plasma nitriding.

(3) The device can control the coupled magnetic field distribution area by adjusting the current of the auxiliary anode electromagnetic coil, thereby controlling the plasma density and energy, and thereby accurately regulating the nitriding composition and structure.

(4) The device can control the ability to absorb electrons by adjusting the auxiliary anode current, thereby controlling the density of the plasma and thereby accurately regulating the nitriding composition and structure.

(5) This device can confine electrons to the side area of the furnace body of the target-auxiliary sun, which increases the density and energy of plasma around the soft base material of the infiltrated part. At the same time, the soft base part rotates in three dimensions, and more ions reach the infiltration area. Ensure the density of the film layer.

(6) The device has plasma nitriding on the side, which on the one hand increases the loading capacity of industrial production and on the other hand avoids the electron shielding effect when fully loaded.

Description of the drawings

Figure 1 is a schematic structural diagram of a high-density plasma uniform nitriding device on the surface of soft base materials.

Among them, 100-chamber; 1-arc source; 2-permanent magnet device; 3-auxiliary anode; 4-adjustable resistance; 5-electromagnetic coil; 6-turret; 7-arc source power supply; 8-auxiliary anode power supply ; 9-Soft base material to be penetrated.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Example 1

As shown in Figure 1, a high-density plasma uniform nitriding device for the surface of soft base materials includes four arc sources 1 respectively arranged on the left, right, front and rear sides of the chamber 100. The arc sources 1 is an electron generating source, and a permanent magnet device 2 is provided behind each arc source 1.

Each arc source 1 is electrically connected to the negative electrode of an arc source power supply 7, wherein the positive electrode of the arc source power supply 7 is grounded; it also includes four auxiliary anodes 3 respectively provided at the four corners of the chamber 100; each An electromagnetic coil 5 is provided behind the auxiliary anode 3 . The auxiliary anode 3 serves as an electron collector and has a certain traction effect on the electrons generated by the arc source 1; the electromagnetic coil 5 and the permanent magnet device 2 perform magnetic field coupling, and the magnetic field distribution obtained by coupling the electromagnetic coil 5 and the permanent magnet device 2 is obtained The multi-level magnetic field with adjustable magnetic mirror ratio distributed along the axial direction causes the electrons generated by the arc source 1 to perform spiral motion under the action of the electromagnetic field, and reach the auxiliary anode 3 to be absorbed.

Each auxiliary anode 3 is electrically connected to the positive electrode of an auxiliary anode power source 8 through an adjustable resistor 4, and the negative electrode of the auxiliary anode power source 8 is grounded.

The positive electrode of the auxiliary anode power supply 8 located on the left side of the chamber 100 is electrically connected to an adjustable resistor 4 respectively, and the two adjustable resistors 4 are respectively connected to the two auxiliary anodes 3 located on the left side of the chamber 100, thereby connecting with the arc source circuit. A parallel circuit is formed; the positive electrode of the auxiliary anode power supply 8 located on the right side of the chamber 100 is electrically connected to an adjustable resistor 4, and the two adjustable resistors 4 are respectively connected to the two auxiliary anodes 3 located on the right side of the chamber 100, so that Form a parallel circuit with the arc source circuit. The auxiliary Yang power supply 8 is adjustable.

The adjustable resistor 4 can adjust the current of the auxiliary anode 3 to control the ability to absorb electrons, control the plasma density, and thereby accurately control the nitriding composition and structure.

There is a rotating frame 6 in the middle of the chamber 100. The rotating frame 6 is loaded with nitrided base material parts, that is, the soft base material 9 to be infiltrated. The soft base material 9 to be infiltrated performs three-dimensional rotation and revolution motion in a certain direction. .

The negative pole of the arc source power supply 7 is connected to the arc source, and the positive pole is grounded. The arc source power supply 7 is adjustable, and the potential of the chamber 100 is also grounded.

Each electromagnetic coil 5 is electrically connected to an independent DC power supply, and its power supply is adjustable.

A large number of electrons evaporated from the arc source 1 are pulled by the auxiliary anode 3 in the chamber 100, and by adjusting the magnetic field distribution area coupled with the permanent magnet device 2 and the electromagnetic coil 5, a large number of electrons perform spiral motion under the action of the electromagnetic field and fill the chamber for separation. The introduced gas atoms are transformed into a plasma state and are injected and diffused into the interior of the soft base material 9 to be infiltrated loaded on the turntable 6 for nitriding. The size of the auxiliary anode current is adjusted through the adjustable resistor 4, resulting in precise control of the ability to absorb electrons, ensuring that the plasma area ionized by the electrons extends and immerses the soft base material to be infiltrated, thereby achieving precise control of the nitriding composition and structure.

This device can not only control the movement trajectory of a large number of electrons generated by arc source evaporation under the action of the electromagnetic field by adjusting the size of the electromagnetic coil current and coupling the magnetic field distribution area of the permanent magnet, thereby controlling the plasma density area and achieving 360° lateral visibility. The scalable annular plasma with variable characteristic parameters can precisely control the nitriding composition and structure; at the same time, it can avoid the electronic shielding effect during industrial large-scale loading.

Example 2

The difference from Embodiment 1 is that a large number of electrons generated by the arc source 1 are pulled by the auxiliary anode 3 in the chamber 100, and the magnetic field of the electromagnetic coil 5 is coupled by adjusting the position of the permanent magnet device 2 to achieve a reliable distribution along the circumference of the chamber. The multi-level magnetic mirror field with adjustable magnetic mirror ratio is used for plasma nitriding work.

Example 3

The difference from Embodiment 1 is that a large number of electrons generated by the arc source 1 are pulled by the auxiliary anode 3 in the chamber 100. By adjusting the electric field of the current coupling auxiliary anode of the arc source 1, the plasma density and energy are controlled, thereby completing the process. Nitriding work for soft base materials.

Applications

316L austenitic stainless steel thermocouple (thermocouple) is a commonly used temperature measuring element in temperature measuring instruments. It is used to directly measure temperature, convert the temperature signal into a thermoelectromotive force signal, and convert it into the temperature of the measured medium through an electrical instrument. The working process of thermocouples will lead to problems such as unstable performance, low measurement accuracy, prolonged thermal response time, small thermoelectric potential rate, poor mechanical strength, short service life, and low overall efficiency. These factors have seriously restricted the development and popularization of austenitic stainless steel thermocouples. When faced with complex and harsh service environments, in order to obtain better overall performance, specific nitriding surface strengthening treatment is required to increase service life and ensure service safety. An austenitic stainless steel thermocouple sample (diameter 20mmX5mm) is selected as the base material. The surface hardness of the base material is 300HV _0.05 .

After the nitriding treatment by the high-density plasma uniform nitriding device on the surface of the soft base material in Example 1, the hardness of the stainless steel thermocouple soft base material increased from 300HV to 1789HV. At the same time, the AlCrN coating was prepared on the soft base material of the stainless steel thermocouple after nitriding treatment. It was found that the hardness and bonding strength of the composite coating (3986HV, 100N) were about 2.5 times that of the single-layer coating (1602HV, 40N).

This is because the nitrided layer creates a hardness gradient between the substrate and coating to reduce the mismatch between the substrate and coating systems, further improving the performance of the composite coating.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art will understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principles and spirit of the invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (10)

1. A high-density plasma uniform nitriding device for the surface of soft base materials, characterized by: including 4 arc sources (1) respectively arranged on the left, right, front and rear sides of the chamber (100) ), a permanent magnet device (2) is provided behind each arc source (1), each arc source (1) is electrically connected to the negative pole of an arc source power supply (7), and the arc source power supply (7) The positive electrode of 7) is grounded; it also includes 4 auxiliary anodes (3) respectively provided at the four corners of the chamber (100); an electromagnetic coil (5) is provided behind each auxiliary anode (3); each auxiliary anode (3) are electrically connected to the positive electrode of an auxiliary anode power supply (8) through an adjustable resistor (4), and the negative electrode of the auxiliary anode power supply (8) is grounded. 2. The high-density plasma uniform nitriding device on the surface of soft base materials according to claim 1, characterized in that: the electromagnetic coil (5) has adjustability, and the electromagnetic coil (5) and the permanent magnet device are adjusted by adjusting the electromagnetic coil (5) and the permanent magnet device. (2) The magnetic field is coupled. 3. The high-density plasma uniform nitriding device on the surface of soft base materials according to claim 1, characterized in that: the arc source power supply (7) connected to the arc source (1) can adjust the current size. 4. The high-density plasma uniform nitriding device on the surface of soft base materials according to claim 1, characterized in that: the auxiliary anode power supply (8) connected to the auxiliary anode (3) can adjust the current size. 5. The device for high-density plasma uniform nitriding on the surface of soft base materials according to claim 1, characterized in that: a turntable (6) is provided in the middle of the chamber (100). 6. The high-density plasma uniform nitriding device for the surface of soft base materials according to claim 5, characterized in that: the soft base material (9) to be infiltrated is placed on the turntable (6). 7. The high-density plasma uniform nitriding device on the surface of soft base materials according to claim 6, characterized in that the current of the auxiliary anode (3) can be adjusted through an adjustable resistor (4). 8. The high-density plasma uniform nitriding device on the surface of soft base materials according to claim 7, characterized in that: the arc source power supply (7), the auxiliary anode power supply (8) and the chamber (100) are all grounded. 9. The device for high-density plasma uniform nitriding on the surface of soft base materials according to claim 8, characterized in that: each electromagnetic coil (5) is electrically connected to an independent DC power supply. 10. The working method of the high-density plasma uniform nitriding device on the surface of soft base materials according to any one of claims 1 to 9, characterized by: A large number of electrons evaporated from the arc source are pulled by the auxiliary anode in the chamber, and by adjusting the magnetic field distribution area coupled by the permanent magnet device and the electromagnetic coil, a large number of electrons perform spiral motion under the action of the electromagnetic field, filling the chamber for ionization of the incoming gas. atoms, so that the gas atoms form a plasma state and are injected and diffused into the soft base material of the infiltrated parts loaded on the turntable for nitriding; the auxiliary anode current is adjusted through the adjustable resistance to regulate the ability to absorb electrons to ensure that the electrons are ionized The plasma area extends and immerses the infiltrated soft base material to achieve precise control of the nitriding composition and structure; Alternatively, by adjusting the position of the permanent magnet device to couple the magnetic field of the electromagnetic coil, a multi-level magnetic mirror field with an adjustable magnetic mirror ratio distributed along the circumference of the chamber can be realized for plasma nitriding work; Alternatively, the electric field of the arc source coupled with the auxiliary anode can be adjusted to control the plasma density and energy, thereby completing the nitriding work of the soft base material to be infiltrated.