CN111074209B

CN111074209B - Surface coating of contact material of vacuum arc-extinguishing chamber and treatment method thereof

Info

Publication number: CN111074209B
Application number: CN201911381450.9A
Authority: CN
Inventors: 宋忠孝; 李玉楼; 崔笑千; 张娜; 李雁淮; 朱晓东
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2021-01-19
Anticipated expiration: 2039-12-27
Also published as: CN111074209A

Abstract

The invention discloses a surface coating of a contact material of a vacuum arc-extinguishing chamber and a processing method thereof, the method adopts a metal copper chromium molybdenum target material to form a CuCrMo alloy film on a CuCr alloy contact material substrate, wherein the CuCrMo alloy film comprises 25-55% of Cr, 5-9% of Mo and the balance of Cu by mass percent, and specifically comprises the following steps: step 1: grinding and polishing the CuCr alloy contact material substrate; step 2: cleaning and drying the polished CuCr alloy contact material substrate; and step 3: and plating a CuCrMo alloy film on the surface of the cleaned and dried CuCr alloy contact material substrate by adopting a magnetron sputtering method, and finally obtaining the CuCr alloy contact material substrate on which the CuCrMo alloy film grows. The thickness of the coating prepared by the treatment method is 1-20 mu m. Compared with CuCr35, the CuCrMo alloy film obtained by the invention has higher voltage resistance, lower shutoff value and longer arcing time.

Description

Surface coating of contact material of vacuum arc-extinguishing chamber and treatment method thereof

Technical Field

The invention belongs to the technical field of sputtering plating, and particularly relates to a surface coating of a contact material of a vacuum arc-extinguishing chamber and a treatment method thereof.

Background

The vacuum circuit breaker is an important component for protecting power equipment by segmented current in a power system, and the trend of development of a vacuum arc-extinguishing chamber towards miniaturization, high capacity and high voltage puts higher requirements on the performance of an electrical contact of a key component of the vacuum arc-extinguishing chamber. The electrical contact produced by the traditional contact material preparation process cannot meet the performance requirement which is increased day by day in an electric power system, so that the prepared electrical contact material with stronger arc ablation resistance and longer service life becomes one of the key technologies and core problems which are urgently needed to be solved by the development of a vacuum circuit breaker.

For the CuCr alloy contact material widely applied to the vacuum circuit breaker, the Cu phase has good electric conduction, heat conduction performance and ductility, the Cr phase has higher melting point and mechanical strength, the alloy matrix can be promoted to be refined, the strengthening phase with uniform dispersion distribution can be formed, and the material has higher mechanical property, voltage resistance, fusion welding resistance and the like. The good electric conduction and heat conduction performance of Cu is favorable for the current breaking capacity of the vacuum circuit breaker, and the high melting point and the mechanical strength of Cr are favorable for ensuring the excellent voltage resistance, fusion welding resistance, arc ablation resistance and other performances. The solubility of Cr in Cu is increased along with the temperature rise, under the action of high-temperature electric arc, a local area on the surface of the contact is melted into liquid, part of Cr is dissolved in the liquid Cu, and during subsequent rapid cooling, Cr is separated out from the Cu to form dispersed, distributed, fine and uniform Cr particles which can be used as nucleation centers of the liquid Cu to accelerate the solidification process of the liquid Cu. In addition, the affinity of Cr to oxygen is high, and the air can be sucked in each breaking process to ensure high vacuum degree of the arc extinguish chamber, so that the service life of the arc extinguish chamber is prolonged. The microstructure and the performance of the CuCr contact material have close relation. The sizes of Cu and Cr phases are reduced, the uniform distribution of the Cu and Cr phases is improved, the hardness and the voltage resistance can be improved, and the conductivity and the interception value are reduced. The nanocrystalline CuCr material can enable the surface of an arc cathode spot to smoothly and continuously move without local concentrated ablation.

However, the traditional CuCr alloy preparation process has the problems of low compactness, large Cr phase size, uneven distribution, severe component segregation and the like, and the alloying or doping method can improve the uniformity of the structure components to a certain extent and refine the size of the phase.

The magnetron sputtering deposition film is a molecular and atomic level deposition process, and the CuCr alloy film which has high compactness, good film-substrate combination, uniform components and accurate control can be prepared by controlling process parameters. The nano-structured film is easily obtained by regulating and controlling process parameters, the uniform distribution of Cr in a Cu phase is ensured, and the microstructure inside the film can be effectively controlled by combining heat treatment, so that the nano-multiphase composite material is obtained. The CuCr alloy film prepared by the magnetron sputtering method has fine nanocrystals, can reduce the work function, improve the hardness and other performance characteristics, has less surface burrs and pollutants, and has important significance in stabilizing the first breakdown performance of vacuum and abnormal ablation direction. By virtue of the structure that the CuCr coating on the surface of the contact is refined and uniform, the movement of an arc cathode spot can be guided, so that the ablation uniformity of the vacuum arc is improved, and a new thought is provided for developing a novel long-life ablation-resistant CuCr contact.

Disclosure of Invention

The invention provides a surface coating of a contact material of a vacuum arc-extinguishing chamber and a treatment method thereof, aiming at the current opening capability, voltage resistance strength and fusion welding resistance of a CuCr contact material.

The invention is realized by adopting the following technical scheme:

a method for processing a surface coating of a contact material of a vacuum arc-extinguishing chamber is characterized in that a CuCrMo alloy film is formed on a CuCr alloy contact material substrate by adopting a metal copper-chromium-molybdenum target material, wherein the CuCrMo alloy film comprises 25-55% of Cr, 5-9% of Mo and the balance of Cu by mass percent, and specifically comprises the following steps:

step 1: grinding and polishing the CuCr alloy contact material substrate;

step 2: cleaning and drying the polished CuCr alloy contact material substrate;

and step 3: and plating a CuCrMo alloy film on the surface of the cleaned and dried CuCr alloy contact material substrate by adopting a magnetron sputtering method, and finally obtaining the CuCr alloy contact material substrate on which the CuCrMo alloy film grows.

The further improvement of the method is that in the step 2, the CuCr alloy contact material after being polished and polished is subjected to ultrasonic cleaning for 10-15 min by using absolute ethyl alcohol and deionized water, and then is dried by using high-purity nitrogen with the purity of 99.99%.

The further improvement of the invention is that in the step 3, a DC magnetron sputtering method is adopted to sputter a Cu target with sputtering power of 60-100W, a DC magnetron sputtering method is adopted to sputter a Cr target with sputtering power of 80-150W, and a radio frequency magnetron sputtering method is adopted to sputter a Mo target with sputtering power of 100-170W.

The invention further improves that in the step 3, the sputtering pressure for magnetron sputtering is between 0.3Pa and 0.7 Pa.

The further improvement of the invention is that in the step 3, the target material is placed on the rotary substrate frame, so that the target material uniformly rotates to prevent the target material from being damaged, wherein the rotating speed omega is in the range of 9 r/min-11 r/min, and the plating thickness of the alloy film is controlled by adjusting the switching time of the baffle plate of the target material; the method comprises the specific steps of simultaneously opening a baffle in front of a Cu target, a Cr target and a Mo target, bombarding the target by adopting plasma, and depositing on a substrate to form a deposition layer with the thickness of 1-20 mu m.

The surface coating of the contact material of the vacuum arc-extinguishing chamber is characterized by being prepared by the method for treating the surface coating of the contact material of the vacuum arc-extinguishing chamber, and the thickness of the coating is 1-20 mu m.

The invention has at least the following beneficial technical effects:

the invention provides a method for processing a surface coating of a contact material of a vacuum arc-extinguishing chamber, which is characterized in that a magnetron co-sputtering method is adopted to coat a CuCrMo alloy film, the magnetron sputtering deposition film is a molecular and atomic level deposition process, and the CuCrMo alloy film which is high in compactness, good in film-substrate combination, uniform in component and accurately controllable can be prepared by controlling process parameters (sputtering power and time). As shown in FIG. 6, the addition of Mo strengthens the Cr phase, serves the purpose of dispersing cathode spots, and is beneficial to eliminating concentrated erosion.

Compared with CuCr35, the CuCrMo columnar crystal size of the surface coating of the contact material of the vacuum arc-extinguishing chamber is reduced, and elements in the film are uniformly distributed. The work function of Mo element is lower than that of Cu and Cr, electrons are easier to release under the electric field intensity, the resistivity of CuCrMo is lower than that of CuCr35, the addition of Mo can reduce the cutoff value and improve the voltage resistance.

In summary, the invention provides a surface coating treatment method for a contact material of a vacuum arc-extinguishing chamber, aiming at the increasingly growing performance requirements of the electrical contact material in an electric power system, the arc ablation resistance and the voltage resistance required by the development of a vacuum circuit breaker, and the like. The following technical effects can be achieved: compared with CuCr35, the CuCrMo alloy film has higher voltage resistance, lower shutoff value and longer arcing time. The solid solution of Mo strengthens the CuCr film, and is beneficial to improving the voltage resistance of the CuCr film. The lower work function of Mo element and the lower resistivity of CuCrMo alloy film are beneficial to reducing the shutoff value. After annealing, the vacuum arc ablation area of the film is increased, the ablation depth is reduced, and the interception value is almost reduced to half of the original value. The grain refinement, resistivity reduction, and surface "pits" and Cu-rich particles of the film after annealing help to reduce cutoff.

Drawings

FIG. 1 is an XRD pattern of a plated CuCrMo9 alloy film;

FIG. 2 is a morphology diagram of a plated CuCrMo9 alloy film;

FIG. 3 is a cross-sectional view of a plated CuCrMo9 alloy film;

FIG. 4 is a graph of film resistivity as a function of composition;

FIG. 5 is a topographic map of CuCr35 after one breakdown;

FIG. 6 is a topography of the CuCrMo9 alloy film after one-time vacuum breakdown;

FIG. 7 is a plot of intercept values for five vacuum breakdowns of a CuCrMo9 film;

FIG. 8 is a graph of the surface topography of the annealed film after one vacuum breakdown.

Detailed Description

The invention is further described below with reference to the following figures and examples.

The invention provides a CuCrMo alloy film taking CuCr alloy contact material as a substrate (the work functions of selected Cu, Cr and Mo elements are shown in Table 1), the table shows that the work function of the Mo element is lower than that of Cu and Cr, and the atomic radius is slightly larger than that of Cr, so that the Mo element is doped into the CuCr film, the conductivity and the refined structure can be ensured to the maximum extent, and the Mo phase becomes a preferential phase of field emission, thereby dispersing and guiding the ablation of electric arc. The film takes CuCr alloy contact material as a substrate. The final thickness of the plated CuCrMo alloy film is in the range of 1-20 μm, and the specific implementation case is as follows:

table 1 shows work functions of Cu, Cr and Mo elements

Example 1

The invention provides a method for processing a surface coating of a contact material of a vacuum arc-extinguishing chamber, which comprises the following steps:

1) and cleaning and drying the CuCr alloy contact material substrate, and cleaning equipment.

2) And sputtering a CuCrMo alloy film on the surface of the CuCr alloy contact material by using a magnetron sputtering method to finally obtain the substrate on which the CuCrMo alloy film grows.

Specifically, in the step 1), the substrate is subjected to ultrasonic cleaning for 10min by using absolute ethyl alcohol and deionized water in sequence, then high-purity nitrogen with the purity of 99.99% is used for blow-drying, dust in a cavity is removed by using a dust collection device for JPG-450a type double-chamber magnetron sputtering equipment, and then the inner wall of the cavity is scrubbed by using the absolute ethyl alcohol.

And 2) sputtering a CuCrMo alloy film by adopting JPG-450a type double-chamber magnetron sputtering equipment. The target was placed on a rotating substrate holder with a rotation speed ω 10 r/min. The target material is a pure Cu target (99.95%), a pure Cr target (99.99%), a pure Mo target (99.99%), and argon with the purity of 99.99% is introduced; the sputtering power is respectively 90W, 130W and 150W, the argon flow is 30sccm, and the working pressure is 0.5 Pa; (ii) a The pre-sputtering time is 10min to remove the surface material of the target.

And plating a CuCrMo alloy film on the CuCr alloy contact material substrate. The method comprises the following specific steps:

and simultaneously opening a baffle in front of the Cu target, the Cr target and the Mo target, bombarding the target for 60min by adopting plasma, and depositing the target on the CuCr substrate to form a deposition layer with the thickness of about 1320 nm. The XRD of the obtained CuCrMo9 alloy film is shown in fig. 1, the scanning of the CuCrMo9 alloy film is shown in fig. 2, and the cross-sectional view of the CuCrMo9 alloy film is shown in fig. 3. As can be seen from fig. 1, the incorporation of Mo results in a larger interplanar spacing than CuCr35, because the atomic radius of Mo is larger than that of Cr. As can be seen from FIG. 2, the surface of the CuCrMo9 film is smooth and flat, and no obvious large particles exist. As can be seen from fig. 3, the film has a columnar structure. Fig. 4 shows the resistivity of the film as a function of the composition, and it can be seen that as Mo atoms are added, the lattice distortion increases, while Mo atoms are dissolved to refine the crystal grains, and the resistivity increases as the grain boundaries increase.

When the CuCrMo9 film is applied to a vacuum breakdown experiment, the CuCrMo9 film has higher voltage resistance, lower shutoff value and longer arcing time compared with CuCr 35. The work function of Mo element is less than that of Cu and Cr, so that electrons are more easily released under the electric field intensity, and the resistivity of the CuCrMo9 film is lower than that of the CuCr35 film, so that the addition of Mo can reduce the cutoff value of the CuCr film. Fig. 5 and fig. 6 show the shapes of CuCr35 after one-time breakdown and CuCrMo after one-time vacuum breakdown, respectively. It can be seen that after one-time breakdown, the breakdown depth of CuCrMo9 is slightly smaller, and the ablation area is larger, which indicates that the addition of Mo is beneficial to the movement of the arc cathode spot. Fig. 7 shows the cutoff distribution of CuCrMo9 film after five times of vacuum breakdown, and it can be seen that the addition of Mo has a positive effect on reducing the cutoff and improving arc ablation. FIG. 8 shows the surface morphology of the annealed film after one vacuum breakdown, overall, the arc ablation area is increased and the ablation depth is decreased after annealing. This indicates that the vacuum arc can move over a wider area of the contact surface after the annealing treatment, thereby reducing the occurrence of concentrated ablation in localized areas.

Example 2

Specifically, in the step 1), the substrate is subjected to ultrasonic cleaning for 15min by using absolute ethyl alcohol and deionized water in sequence, then high-purity nitrogen with the purity of 99.99% is used for blow-drying, dust in a cavity is removed by using a dust collection device for JPG-450a type double-chamber magnetron sputtering equipment, and then the inner wall of the cavity is scrubbed by using the absolute ethyl alcohol.

And 2) sputtering a CuCrMo alloy film by adopting JPG-450a type double-chamber magnetron sputtering equipment. The target was placed on a rotating substrate holder with a rotation speed ω 10 r/min. The target material is a pure Cu target (99.95%), a pure Cr target (99.99%), a pure Mo target (99.99%), and argon with the purity of 99.99% is introduced; the sputtering power is respectively 90W, 130W and 100W, the argon flow is 30sccm, and the working pressure is 0.5 Pa; (ii) a The pre-sputtering time is 10min to remove the surface material of the target.

and simultaneously opening a baffle in front of the Cu target, the Cr target and the Mo target, bombarding the target for 70min by adopting plasma, and depositing the target on the CuCr substrate to form a deposition layer with the thickness of about 1210nm, wherein the obtained alloy film comprises the CuCrMo 5.

Example 3

Specifically, in the step 1), the substrate is subjected to ultrasonic cleaning for 12min by using absolute ethyl alcohol and deionized water in sequence, then high-purity nitrogen with the purity of 99.99% is used for blow-drying, dust in a cavity is removed by using a dust collection device for JPG-450a type double-chamber magnetron sputtering equipment, and then the inner wall of the cavity is scrubbed by using the absolute ethyl alcohol.

And 2) sputtering a CuCrMo alloy film by adopting JPG-450a type double-chamber magnetron sputtering equipment. The target was placed on a rotating substrate holder with a rotation speed ω 9 r/min. The target material is a pure Cu target (99.95%), a pure Cr target (99.99%), a pure Mo target (99.99%), and argon with the purity of 99.99% is introduced; the sputtering power is respectively 60W, 150W and 140W, the argon flow is 30sccm, and the working pressure is 0.3 Pa; (ii) a The pre-sputtering time is 10min to remove the surface material of the target.

and simultaneously opening a baffle in front of the Cu target, the Cr target and the Mo target, bombarding the target for 75min by using plasma, and depositing the target on the CuCr substrate to form a deposition layer with the thickness of about 1370nm, wherein the obtained alloy film comprises the CuCr55 Mo.

Example 4

Specifically, in the step 1), the substrate is subjected to ultrasonic cleaning for 13min by using absolute ethyl alcohol and deionized water in sequence, then high-purity nitrogen with the purity of 99.99% is used for blow-drying, dust in a cavity is removed by using a dust collection device for JPG-450a type double-chamber magnetron sputtering equipment, and then the inner wall of the cavity is scrubbed by using the absolute ethyl alcohol.

And 2) sputtering a CuCrMo alloy film by adopting JPG-450a type double-chamber magnetron sputtering equipment. The target was placed on a rotating substrate holder with a rotation speed ω 11 r/min. The target material is a pure Cu target (99.95%), a pure Cr target (99.99%), a pure Mo target (99.99%), and argon with the purity of 99.99% is introduced; the sputtering power is respectively 100W, 80W and 170W, the argon flow is 30sccm, and the working pressure is 0.7 Pa; (ii) a The pre-sputtering time is 10min to remove the surface material of the target.

and simultaneously opening a baffle in front of the Cu target, the Cr target and the Mo target, bombarding the target for 100min by adopting plasma, and depositing the target on the CuCr substrate to form a deposition layer with the thickness of about 1670nm, wherein the obtained alloy film comprises the CuCr25 Mo.

Claims

1. A method for processing a surface coating of a contact material of a vacuum arc-extinguishing chamber is characterized in that a CuCrMo alloy film is formed on a CuCr alloy contact material substrate by adopting a metal copper-chromium-molybdenum target material, wherein the CuCrMo alloy film comprises 25-55% of Cr, 5-9% of Mo and the balance of Cu by mass percent, and specifically comprises the following steps:

step 1: grinding and polishing the CuCr alloy contact material substrate;

step 2: cleaning and drying the polished CuCr alloy contact material substrate;

2. The method for processing the surface coating of the contact material of the vacuum arc-extinguishing chamber according to claim 1, wherein in the step 2, the polished CuCr alloy contact material is subjected to ultrasonic cleaning for 10-15 min by using absolute ethyl alcohol and deionized water, and then is dried by blowing with high-purity nitrogen with the purity of 99.99%.

3. The method for surface coating treatment of contact material of vacuum arc-extinguishing chamber according to claim 1, wherein in step 3, a Cu target is sputtered by a DC magnetron sputtering method with a sputtering power of 60-100W, a Cr target is sputtered by a DC magnetron sputtering method with a sputtering power of 80-150W, and a Mo target is sputtered by a RF magnetron sputtering method with a sputtering power of 100-170W.

4. The method for coating the surface of the contact material of the vacuum arc-extinguishing chamber according to claim 1, wherein in the step 3, the sputtering pressure for magnetron sputtering is between 0.3Pa and 0.7 Pa.

5. The method for surface coating treatment of contact material of vacuum arc-extinguishing chamber according to claim 1, characterized in that in step 3, the target material is placed on a rotating substrate holder, the target material is rotated uniformly to prevent the target material from being damaged, wherein the rotating speed ω is in the range of 9r/min to 11r/min, and the coating thickness of the alloy film is controlled by adjusting the switching time of the baffle plate of the target material; the method comprises the specific steps of simultaneously opening a baffle in front of a Cu target, a Cr target and a Mo target, bombarding the target by adopting plasma, and depositing on a substrate to form a deposition layer with the thickness of 1-20 mu m.

6. A surface coating of a contact material of a vacuum arc extinguish chamber, which is prepared by the method for processing the surface coating of the contact material of the vacuum arc extinguish chamber according to any one of claims 1 to 5, and the thickness of the coating is 1-20 μm.