CN111621752B - Preparation process of AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nano composite coating - Google Patents

Abstract

The invention discloses a preparation process of an AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nano composite coating, which belongs to the technical field of composite coating preparation. The process adopts arc ion coating technology to coat, and the target materials are metal Cr target, AlCr target and AlCrSi target. Before coating, argon glow discharge cleaning was carried out, then the Cr target was turned on for ion bombardment cleaning on the surface of the substrate, then a CrN transition layer was deposited, and finally nitrogen and oxygen were introduced as reactive gases to alternately turn on the AlCrSi target and the AlCr target, and repeat in turn. AlCrSiN layers, AlCrN layers, AlCrON layers and AlCrN layers are deposited. The multi-layer nano-composite coating prepared by the invention has the advantages of simple process, dense coating structure, strong bonding force between the coating and the substrate, high hardness and strength, and good wear resistance.

Description

Preparation Technology of AlCrSiN/AlCrN/AlCrON/AlCrN Multilayer Nanocomposite Coatings

technical field

The invention relates to the technical field of preparation of multi-component nano-composite coatings, in particular to a preparation process of AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nano-composite coatings.

Background technique

With the development of low temperature and low pressure vapor deposition technology, magnetron sputtering, arc ion plating and PECVD can deposit films that do not exist in equilibrium state in non-equilibrium state, especially the emergence of assisted deposition technologies such as plasma and ion beam, The ability to synthesize high-quality coatings at lower temperatures has greatly promoted the development of hard coatings. In recent years, improving the bonding strength of the coating and the substrate, the strength, hardness, toughness, oxidation resistance, high temperature resistance and wear resistance of the tool coating can broaden the application of the coated tool in dry cutting, and meet the difficult requirements. High-speed cutting requirements of machined materials and conditions of speed, feed rate, reliability, wear resistance and good cutting controllability required by modern metal processing. With the continuous updating of coating vacuum vapor deposition technology, tool coating has developed from the initial single layer to multi-layer composite, gradient coating, nano-composite structure, and recently, a hybrid composite structure coating has emerged. The performance not only significantly increases the service life of the coated tool, but also greatly saves processing time, improves processing efficiency, improves the quality of the machined surface, and promotes the rapid development of the processing and manufacturing industry.

In order to develop a multi-layer nano-composite coating with dense structure, high hardness and high wear resistance, this patent adopts the arc ion plating technology to deposit AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nano-composite coating on the metal or alloy substrate to further improve the performance of the coating. Mechanical properties of coated tools and extended service life.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation process of AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating, the prepared AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating has both high hardness and high wear resistance and high thermal stability.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

A preparation process of AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating. The process is to first deposit a CrN transition layer on a substrate by using an arc ion plating technology, and then sequentially reciprocate the deposition of an AlCrSiN layer, an AlCrN layer, an AlCrON layer and an AlCrN layer. layer to obtain the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating.

In this process, pure metal Cr target, AlCr alloy target and AlCrSi alloy target are selected as target materials, and the purity of the target material is all 99.9wt.%; when depositing each layer, the arc current is set to 60-100A.

The technology of the present invention specifically comprises the following steps:

(1) Put the pretreated substrate on the central turntable of the coating chamber, and pump the air pressure of the vacuum chamber to below 3.0×10 ^-3 Pa;

(2) Glow discharge cleaning is performed on the substrate first, and then a CrN transition layer with a thickness of 100-300 nm is deposited on the surface of the substrate to improve the bonding force between the working layer and the substrate;

(3) Deposition of multi-layer composite coating: firstly open the AlCrSi alloy target, pass in argon and nitrogen, and deposit the AlCrSiN layer; then only open the AlCr target, pass in argon and nitrogen, and deposit the AlCrN layer; then pass in oxygen to deposit AlCrON layer; finally stop feeding oxygen, only feeding argon and nitrogen to deposit AlCrN layer;

(4) Repeat the process of step (3) several times, and set different modulation periods and deposition times of the coating according to the total thickness of the coating to obtain the AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating.

The process of glow discharge cleaning in the above step (2) is as follows: first, the substrate is cleaned by high pulse negative bias glow discharge for 10 to 30 minutes, after the glow cleaning, the Cr target is turned on, and the pulse bias voltage is adjusted to -800V, -600V, The surface of the substrate was cleaned by ion bombardment for 2min at -400V and -200V respectively.

In the above step (2), the specific process of the glow discharge cleaning is as follows: heating the furnace chamber to 400-500° C., feeding 300-500 sccm of argon gas, setting a pulse bias voltage of -600--1000V, and glowing the substrate. Photodischarge cleaning; the ion bombardment cleaning process is: after glow discharge cleaning, turn on the Cr target, adjust the argon flow rate to 50-150sccm, and sequentially under -800V, -600V, -400V and -200V pulse negative bias conditions Wash for 2min each.

In the above step (2), the process of depositing the CrN transition layer is as follows: after glow discharge and ion bombardment cleaning, set the pulse bias voltage to -60 to -100V, the duty cycle is 60% to 90%, turn on the Cr target, and pass in the The flow rate of argon gas is 50 sccm, the flow rate of nitrogen gas is 200 sccm, the deposition pressure is adjusted to 0.5-1.2 Pa, and the CrN transition layer is deposited for 10-30 minutes.

In the above step (3), when depositing the AlCrSiN layer, set a pulse bias voltage of -70 to -120V, a duty ratio of 60% to 90%, and pass in argon and nitrogen to keep the deposition pressure at 0.8 to 1.3Pa; deposit the AlCrN layer When depositing the AlCrON layer, set the pulse bias voltage -80~-100V, the duty ratio is 60%~90%, and pass argon and nitrogen gas to keep the deposition pressure at 1.5~3Pa; when depositing the AlCrON layer, set the pulse bias voltage -80~-100V , the duty ratio is 60% to 90%, and argon, oxygen and nitrogen are introduced to keep the deposition pressure at 2 to 3Pa.

In the above step (3), when depositing the AlCrSiN coating and the AlCrN coating, the flow of argon gas is 50 sccm, the flow of nitrogen gas is 600 sccm, and the total flow is 650 sccm; when the AlCrON coating is deposited, the flow of argon gas is 50 sccm, and the flow of nitrogen gas is 50 sccm. is 600sccm, the oxygen flow is 20sccm, and the total flow is 670sccm.

The substrate is metal or cemented carbide, and the prepared AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating is composed of an AlCrSiN layer, an AlCrN layer, an AlCrON layer and an AlCrN layer. -800nm, the number of cycles is ≥4, the modulation ratio of the AlCrSiN layer, the AlCrN layer, the AlCrON layer and the AlCrN layer is 3:1:1:1, and the total thickness of the coating is controlled to 3μm.

The AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating is composed of nanocrystals with a face-centered cubic structure embedded in an amorphous layer to form a nanocomposite structure, and no low-hardness hexagonal phase is formed. )N (110) and (200) planes are preferentially grown.

The design mechanism of the present invention is as follows:

The present invention strengthens the coating by adding Si element in the AlCrN coating, utilizing the solid solution strengthening effect of Al and Cr elements and forming a composite structure of amorphous Si ₃ N ₄ encapsulating nanocrystals, and adding O element in the AlCrN coating. , Use the thermal stability and thermal barrier ability of the AlCrON coating to improve the heat resistance of the coating, and then use the high toughness of the AlCrN coating to wrap the AlCrON coating, and stack the AlCrSiN layer, AlCrN layer, AlCrON layer and AlCrN layer on each other Arrangement to form a multi-layer nanocomposite coating can make the AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer composite coating have excellent characteristics significantly better than single-layer coating, and meet the needs of high-speed cutting and dry cutting conditions.

The nano-multilayer composite coating prepared by the invention is a modulation structure, that is, it has a certain repetition period. Alternately depositing three different coatings with nano-scale dimensions, the obtained multilayer nanocomposite structure will exhibit a superhard phenomenon with abnormally increased hardness, and the advantages of different materials are combined to overcome the shortcomings of the single-layer film and realize the coating's high performance. High hardness, high toughness and excellent wear resistance.

The advantages of the present invention are as follows:

1. The AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating developed by the present invention has high hardness and toughness, low friction coefficient and good wear resistance.

2. The AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating developed by the present invention has good high temperature thermal stability and corrosion resistance, and can be used in the field of high-speed dry cutting.

3. The AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating developed by the present invention has uniform thickness and compact structure, and has good bonding strength with the substrate.

4. The AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating developed by the present invention has good repeatability of the preparation process, wide application range and very strong practicability.

Description of drawings

Figure 1 is the diffraction pattern of the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating prepared by arc ion plating technology; wherein: (a) The modulation ratio of the AlCrSiN layer, the AlCrN layer, the AlCrON layer and the AlCrN layer is 5:1 : 1:1; (b) the modulation ratio of AlCrSiN layer, AlCrN layer, AlCrON layer and AlCrN layer is 4:1:1:1; (c) The modulation ratio of AlCrSiN layer, AlCrN layer, AlCrON layer and AlCrN layer is 3 : 1:1:1; (d) the modulation ratio of the AlCrSiN layer, the AlCrN layer, the AlCrON layer and the AlCrN layer is 2:1:1:1; (e) the modulation ratio of the AlCrSiN layer, the AlCrN layer, the AlCrON layer and the AlCrN layer is 1:3:3:3.

Figure 2 shows the surface topography of the AlCrSiN/AlCrN/AlCrON/AlCrN nanocomposite coating prepared by arc ion plating technology.

Figure 3 is a cross-sectional topography of the AlCrSiN/AlCrN/AlCrON/AlCrN nanocomposite coating prepared by arc ion plating technology.

Figure 4 shows the nanoindentation test curve of the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating prepared by arc ion plating technology.

Figure 5 shows the morphologies of the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coatings prepared by arc ion plating technology after scratch testing.

Figure 6 shows the friction coefficient test curve of the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating prepared by arc ion plating technology.

Detailed ways

The present invention will be described in further detail below through examples.

In the following examples, AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coatings were deposited on the substrate by using V-TECH AIP 650/750 automatic arc ion coating machine produced by Dalian Vitec Technology Co., Ltd.

In the deposition process of the multilayer nanocomposite coating, the substrate is metal or cemented carbide, and the target material is pure metal Cr target, AlCr alloy target and AlCrSi alloy target; when depositing the multilayer nanocomposite coating, the Cr target is turned on first, and then alternately Turn on the AlCrSi target and the AlCr target to deposit the corresponding AlCrSiN layer, AlCrN layer and AlCrON layer, and control the deposition pressure of each layer, the flow rate of the gas and the arc current parameters of each target respectively. The AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating is composed of the AlCrN layer, the AlCrON layer and the AlCrN layer which are successively stacked in turn.

Example 1

In this example, an AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating is deposited on a polished 304 stainless steel sheet, and the size of the sample is 25mm×30mm×1mm.

The substrate was pre-treated first: ultrasonically cleaned in acetone, ultrapure water and alcohol for 15 min, then dried with high-purity nitrogen, and placed on a sample holder in a vacuum chamber.

The coating process is carried out on an AIP-650 arc ion coating machine, using pure metal Cr target, alloy AlCr target, and alloy AlCrSi target (purity are all 99.9wt.%) with a diameter of 100mm as the target material. Use high-purity argon, nitrogen and oxygen.

The targets are evenly distributed on the inner wall of the furnace body of the arc ion plating equipment to ensure a high plasma concentration in the furnace chamber during the deposition process; the pretreated substrates are placed on the central turntable of the coating chamber.

Use a combination of mechanical pump and molecular pump to evacuate to make the vacuum chamber pressure below 3.0×10 ^-3 Pa, then turn on the heating system to raise the temperature to 420°C, pass argon gas for 400sccm into the vacuum chamber, set the pulse bias to -800V, and set the pulse bias to -800V. The surface of the sample was cleaned by glow discharge for 20 min.

Then turn on the Cr target, adjust the argon gas flow to 50-150sccm, and adjust the pulse negative bias to -800V, -600V, -400V, -200V for 2min ion bombardment cleaning;

Then set the pulse bias to -100V (duty ratio 60%), turn on the Cr target, pass 50sccm of argon, 200sccm of nitrogen, keep the deposition pressure at 0.5Pa, and deposit a CrN transition layer for 20min;

Then, the AlCrSiN layer, the AlCrN layer, the AlCrON layer and the AlCrN layer are sequentially and repeatedly deposited on the CrN transition layer to finally obtain the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating.

When depositing multi-layer nanocomposite coatings, the heating system is heated to 480°C, AlCrSi target and AlCr target are turned on alternately, and the arc current is set to 100A; ratio of 60%), feed argon flow rate of 50sccm, nitrogen flow rate of 600sccm, and adjust the deposition pressure to 1.05Pa; turn on the AlCr target, and set the pulse bias to -100V (duty ratio 60%) when depositing each AlCrN layer The flow rate of argon gas is 50sccm, the flow rate of nitrogen gas is 600sccm, and the deposition pressure is adjusted to 1.05Pa; when the AlCr target is turned on to deposit each layer of AlCrON layer, the pulse bias voltage is set to -100V (duty ratio 60%), the flow rate of argon gas is 50sccm, and the flow rate of nitrogen gas is set to 50sccm. 600sccm, oxygen flow rate of 20sccm, adjusted deposition pressure to 1.05Pa, set coating modulation period to 300nm, deposited 10 periods (40 layers in total), and the modulation ratio of AlCrSiN layer, AlCrN layer, AlCrON layer and AlCrN layer in one cycle was 3 :1:1:1, the total thickness of the deposited coating is controlled to 3μm.

Curve (c) in FIG. 1 is the XRD diffraction spectrum of the AlCrSiN/AlCrN/AlCrON/AlCrN nanocomposite coating prepared in this example, and the coating consists of nanocrystals with a face-centered cubic structure embedded in an amorphous layer to form a nanocomposite structure, There is no low-hardness hexagonal phase, and the coating grows preferentially along the (110) and (200) planes of (Cr,Al)N.

AlCrSiN/AlCrN/AlCrON/AlCrN nanocomposite coatings with other modulation ratios were also prepared according to the process of Example 1, and their XRD diffraction spectra are shown in curve (a), curve (b), curve (e), curve ( d) shown. The performance test shows that its hardness and friction properties are inferior to the multi-layer composite coatings with AlCrSiN layer, AlCrN layer, AlCrON layer and AlCrN layer whose modulation ratio is 3:1:1:1.

Figure 2 shows the surface topography of the nanocomposite coating. The coating exhibits the characteristics of a typical arc ion plating coating, with a dense and uniform structure and a large number of large particles on the surface.

Figure 3 shows the cross-sectional topography of the nanocomposite coating. The thickness of the coating is about 3 μm. The coating is well combined with the substrate, and the modulation period and delamination of the coating can be clearly seen.

Fig. 4 is the loading-unloading curve of coating hardness tested by nanoindenter. With the indentation of the nano-indentation probe, the hardness measurement value of the coating increases rapidly at first, reaching a plateau value, and then gradually decreases due to the substrate effect, and the plateau value is taken as the average hardness value of the coating. It can be seen from the figure that the hardness of the multi-layer nanocomposite coating in this embodiment is about 31.0 GPa.

Figure 5 shows the scratch morphology of the multilayer nanocomposite coating tested with a scratch meter. As can be seen from the figure, the coating adhesion is good, about 96.1N.

Figure 6 shows the friction coefficient curve of the multi-layer nanocomposite coating tested by a high temperature friction machine. The average friction coefficient of the coating is low, about 0.62.

Example 2

In this example, the AlCrSiN/AlCrN/AlCrON/AlCrN multi-layer nanocomposite coating is deposited on the polished YT cemented carbide substrate, and the size of the sample is 25mm×25mm×3mm.

The substrate was pretreated first: ultrasonically cleaned in acetone, ultrapure water and alcohol for 15mim each, then dried with high-purity nitrogen, and placed on a sample holder in a vacuum chamber.

The coating process is carried out on AIP-650 arc ion coating machine. The target materials are pure metal Cr target, alloy AlCr target and AlCrSi alloy target (purity are all 99.9wt.%) with a diameter of 100mm. The working gas and reaction gas are selected respectively. High purity argon, nitrogen and oxygen.

Each target is evenly installed around the vacuum chamber of the arc ion plating equipment to ensure a high plasma concentration in the furnace chamber during the deposition process; the pretreated substrate is placed on the central turntable of the coating chamber;

Use a combination of mechanical pump and molecular pump to evacuate. When the pressure of the vacuum chamber reaches below 3.0×10 ^-3 Pa, turn on the heating system and raise the temperature to 420°C. Then pass argon gas into the vacuum chamber for 400sccm, and set the pulse bias to -800V. The surface of the sample was cleaned by glow discharge for 20 min.

Then turn on the Cr target, adjust the argon gas flow to 50-150sccm, and adjust the pulse negative bias voltage to -800V, -600V, -400V, -200V for ion bombardment cleaning for 2 minutes each;

Then set the pulse bias to -100V (duty ratio 60%), turn on the Cr target, pass 50sccm of argon, 200sccm of nitrogen, keep the deposition pressure at 0.5Pa, and deposit a CrN transition layer for 20min;

Finally, the heating system is heated to 480°C, the AlCrSi target and the AlCr target are turned on alternately, and the arc current is both set to 100A; when the AlCrSi target is turned on to deposit the AlCrSiN layer: set the pulse bias to -100V (duty ratio 60%), and the flow of argon gas is introduced. 50sccm, nitrogen flow rate 600sccm, keep the deposition pressure at 1.05Pa; when the AlCr target is turned on to deposit the AlCrN layer, set the pulse bias to -100V (duty ratio 60%), pass in the argon flow rate of 50sccm, nitrogen flow rate of 600sccm, and keep the deposition pressure as 1.05Pa; when the AlCr target is turned on to deposit the AlCrON layer, the pulse bias voltage is set to -100V (60% duty cycle), and the flow rate of argon gas is 50sccm, the flow rate of nitrogen gas is 600sccm, and the flow rate of oxygen gas is 20sccm. The deposition pressure is kept at 1.05Pa, and the coating is set. The modulation period is 300 nm, and 10 periods (40 layers in total) are deposited. The modulation ratio of the AlCrSiN layer, the AlCrN layer, the AlCrON layer and the AlCrN layer in one period is 3:1:1:1, and the total thickness of the deposited coating is controlled to be 3 μm.

The phase composition and microstructure of the multilayer nanocomposite coating prepared in this example are the same as those in Example 1, and the nanocomposite is formed by embedding (Cr, Al)N nanocrystals of face-centered cubic structure in the amorphous layer. structure. The total thickness of the coating is about 3μm, and the hardness is as high as 31.0Gpa.

Claims (5)

1. A preparation process of AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nano composite coating is characterized by comprising the following steps: the process comprises the steps of depositing a CrN transition layer on a substrate by adopting an arc ion coating technology, and sequentially depositing an AlCrSiN layer, an AlCrN layer, an AlCrON layer and an AlCrN layer on the CrN transition layer in a reciprocating manner, so as to obtain the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nano composite coating; in the process, the target material is selected from a pure metal Cr target, an AlCr alloy target and an AlCrSi alloy target, and the purity of the target material is 99.9 wt%; when each layer is deposited, arc current is set to be 60-100A;

the process specifically comprises the following steps:

(1) placing the pretreated substrate on a central rotating stand of a coating chamber, and pumping the vacuum chamber to 3.0 × 10^-3 Pa below;

(2) firstly, carrying out glow discharge cleaning on a substrate, and then depositing a CrN transition layer with the thickness of 100-300 nm on the surface of the substrate to improve the binding force between a working layer and the substrate;

(3) depositing a multi-layer composite coating: firstly, starting an AlCrSi alloy target, introducing argon and nitrogen, and depositing an AlCrSiN layer; then only starting an AlCr target, introducing argon and nitrogen, and depositing an AlCrN layer; then introducing oxygen to deposit an AlCrON layer; finally, closing the oxygen valve, only introducing argon and nitrogen, and depositing an AlCrN layer; wherein: when an AlCrSiN layer is deposited, setting pulse bias voltage of-70V to-120V, duty ratio of 60% to 90%, and introducing argon and nitrogen to keep deposition pressure of 0.8 Pa to 1.3 Pa; when an AlCrN layer is deposited, setting a pulse bias voltage of-80 to-100V, setting the duty ratio of 60 to 90 percent, and introducing argon and nitrogen to adjust the deposition pressure to 1.5 to 3 Pa; when an AlCrON layer is deposited, setting a pulse bias voltage of-80 to-100V, setting the duty ratio of 60 to 90 percent, and introducing argon, oxygen and nitrogen to keep the deposition pressure of 2 to 3 Pa; when the AlCrSiN coating and the AlCrN coating are deposited, the flow of argon is 50sccm, the flow of nitrogen is 600sccm, and the total flow is 650 sccm; when the AlCrON coating is deposited, introducing argon gas flow of 50sccm, nitrogen flow of 600sccm, oxygen flow of 20sccm and total flow of 670 sccm;

(4) repeating the process of the step (3) for multiple times, and setting different modulation periods and deposition times of the coating according to the total thickness of the required coating to obtain the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nano composite coating;

the matrix is metal or hard alloy, the prepared AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nano composite coating is formed by sequentially overlapping an AlCrSiN layer, an AlCrN layer, an AlCrON layer and an AlCrN layer into a period, the modulation period of the coating is 50-800nm, the period number is more than or equal to 4, and the modulation ratio of the AlCrSiN layer, the AlCrN layer, the AlCrON layer and the AlCrN layer is 3:1:1:1, the total thickness of the deposited coating is controlled to be 3 μm.

2. The process of preparing AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating of claim 1, wherein: the glow discharge cleaning process in the step (2) comprises the following steps: firstly, cleaning a substrate by adopting high-pulse negative bias glow discharge for 10-30 min, starting a Cr target after the glow discharge cleaning, and respectively carrying out ion bombardment cleaning on the surface of the substrate for 2min by sequentially adjusting pulse bias to-800V, -600V, -400V and-200V.

3. The process of preparing the multilayer nanocomposite coating of AlCrSiN/AlCrN/AlCrON according to claim 2, wherein: the glow discharge cleaning process in the step (2) comprises the following steps: heating the furnace chamber to 400-500 ℃, introducing argon gas of 300-500 sccm, setting pulse bias voltage of-600 to-1000V, and performing glow discharge cleaning on the substrate; the ion bombardment cleaning process comprises the following steps: after glow discharge cleaning, starting the Cr target, adjusting the argon flow to be 50-150 sccm, and sequentially cleaning for 2min under the pulse negative bias conditions of-800V, -600V, -400V and-200V.

4. The process of preparing AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating of claim 1, wherein: the process of depositing the CrN transition layer in the step (2) is as follows: after glow discharge and ion bombardment cleaning, setting pulse bias voltage to be-60 to-100V, duty ratio to be 60 to 90 percent, starting a Cr target, introducing argon gas flow to be 50sccm and nitrogen gas flow to be 200sccm, adjusting the deposition pressure to be 0.5 to 1.2Pa, and depositing a CrN transition layer for 10 to 30 min.

5. The process of preparing AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nanocomposite coating of claim 1, wherein: the AlCrSiN/AlCrN/AlCrON/AlCrN multilayer nano composite coating is formed by embedding nanocrystals with a face-centered cubic structure in an amorphous layer, a low-hardness hexagonal phase is not generated, and the coating preferentially grows along a (110) crystal face and a (200) crystal face of (Cr, Al) N.

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