Ultrasonic cleaning of a stamping die and preparation of CrAlN coating on its surface

Abstract

The present invention discloses an ultrasonic cleaning method for a stamping die and preparation of a CrAlN coating on its surface, belonging to the technical field of preparation of high-strength plate stamping dies. Specifically, the invention relates to a method of using a stamping die as a substrate, hardening the substrate by nitriding, improving the bearing capacity of the substrate, and avoiding the eggshell effect. The first layer in the coating is a bonding layer, which ensures the adhesion of the entire substrate and the coating. The second layer is an energy absorption layer with a relatively loose structure. When high-intensity pressure comes from the outside, the stress can be absorbed and transferred, similar to the effect of "sponge elasticity". The third layer is a main functional layer, which takes on most of the impact stress from the outside. The fourth layer is a surface functional layer, which is a surface layer with high hardness to resist wear with the processed material.

Description

[0001] This application is a divisional application of Chinese patent application 202310523837.3, entitled “Ultrasonic cleaning of a stamping die and preparation of CrAlN coating on its surface,” filed on May 11, 2023. Technical Field

[0002] The invention belongs to the technical field of high-strength plate stamping die preparation, and particularly relates to ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Background Art

[0003] CN101818321A discloses a high-hardness and high-elastic modulus CrAlN protective coating and its preparation method. The document states that the bottom layer is a Cr transition layer with a thickness of 400-600nm, and the outer layer is a CrAlN coating, which is a dense ceramic coating with a thickness of 2.2-2.9μm. The preparation method adopted is sputtering coating. A high-hardness and high-toughness CrAlN coating is obtained by this method. CN114645248A discloses a surface anti-bite film material and its preparation method. The document states that the bottom layer Cr, the transition layer CrN and the CrAlBN functional layer are prepared by a multi-arc ion plating method to obtain a film, thereby solving the problem of nut bonding in aviation. CN113416926A discloses a nano-multilayer structure transition metal nitride coating and its preparation method and application. A laminated coating of CrAlN coating is prepared by a multi-arc ion plating method to improve the chip performance of a bimetallic band saw blade.

[0004] A drawback of existing technologies is that the resulting CrAlN coatings are relatively thin, typically less than 5μm. This is primarily due to the high stress in the coating. Excessively thick coatings can lead to disintegration between the coating and the substrate, resulting in a loss of protective properties. However, for high-strength stamping dies, coatings that are too thin offer limited protection. Therefore, designers must optimize the coating structure to achieve a nanocoating with high hardness, good toughness, and sufficient thickness. Summary of the Invention

[0005] The purpose of the present invention is to provide an ultrasonic cleaning method for a stamping die with high hardness and high elastic modulus and the preparation of a CrAlN coating on its surface.

[0006] Through a rational coating structure design, this invention achieves a nano-coating for stamping dies. This coating exhibits high hardness, good toughness, and a coating-to-substrate bonding strength of ≥80N. The coating can be as thick as 10μm and still maintain good results. In contrast, CrAlN coatings are typically thinner, typically less than 5μm.

[0007] The technical solutions adopted by the present invention to achieve the above-mentioned purpose are:

[0008] A CrAlN coating for a mold comprises: a base material, and a CrAlN coating bonded to the base material; the CrAlN coating comprises a bonding layer, an energy absorption layer, a primary functional layer, and a surface functional layer; the bonding layer is bonded to the base material, the energy absorption layer is bonded to the bonding layer, the primary functional layer is bonded to the energy absorption layer, the primary functional layer comprises at least a cyclic layer of a CrAlN layer and a CrAl layer; and the surface functional layer is bonded to the primary functional layer. The CrAlN coating prepared by the present invention comprises a bonding layer, an energy absorption layer, a primary functional layer, and a surface functional layer, which are combined to form a high-performance CrAlN coating. The most important feature of the coating is the arrangement of the cyclic layer on the primary functional layer. In the present invention, the primary functional layer is formed by cyclically depositing at least a CrAlN layer and a CrAl layer, and the number of cyclic depositions of the CrAlN layer and the CrAl layer affects their performance. The more cyclic depositions of the CrAlN layer and the CrAl layer, the better, but optimal performance is achieved at a certain number of times.

[0009] Preferably, the base material is a stamping die.

[0010] Preferably, the CrAlN coating has a thickness of 6.4 μm or more.

[0011] Preferably, the CrAlN coating has a thickness of 10 μm or more.

[0012] Preferably, the bonding layer has a thickness of 0.4 μm or more.

[0013] Preferably, the thickness of the energy absorbing layer is 2 μm or more.

[0014] Preferably, the thickness of the main functional layer is 3 μm or more.

[0015] Preferably, the thickness of the surface functional layer is 1 μm or more.

[0016] Preferably, the coating thickness of the Cr bonding layer is 400-800 nm; the coating thickness of the energy absorption layer is 2-4 μm; the coating thickness of the main functional layer is 3-6 μm; and the thickness of the surface functional layer is 1-2 μm.

[0017] The main functional layer includes alternating deposition of CrAlN layer and CrAl layer, one deposition of CrAlN layer and CrAl layer is one modulation cycle, and the number of cyclic deposition layers of CrAlN layer and CrAl layer is 2-10 layers, that is, the modulation cycle is 2-10.

[0018] A method for preparing a CrAlN coating on the surface of a stamping die after ultrasonic cleaning, comprising: depositing the CrAlN coating on the die by a multi-arc ion plating method, the CrAlN coating comprising a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer, the bonding layer being bonded to a base material, the energy absorption layer being bonded to the bonding layer, the main functional layer being bonded to the energy absorption layer, the main functional layer containing at least a circulating layer of a CrN layer and a CrAl layer; the surface functional layer being bonded to the main functional layer; and ultrasonically cleaning the die.

[0019] Preferably, the deposition of the bonding layer: turn on the Cr target, set the target current to 110-130A, bias to 700-900V, 5-15s, then bias to 500-700V, 5-15s, then bias to 300-500V, 5-15s, then bias to 200-250V, 500-700s.

[0020] Preferably, the energy absorption layer is deposited by turning on the Cr target, introducing nitrogen at 500-600 sccm, setting the pressure to 0.4-0.6 Pa, setting the target current to 140-160 A, the bias voltage to 5-15 V, and the deposition time to 7000-8000 s;

[0021] Preferably, the deposition of the main functional layer: turn off the Cr target, turn on the CrAl target, introduce 700-800 sccm of nitrogen, set the gas pressure to 3-5 Pa, set the target current to 150-250 A, the bias voltage to 90-110 V, and the time to 500-700 s; turn off the nitrogen, keep other setting parameters unchanged, and the time is 1000-1500 s.

[0022] Preferably, during the deposition of the surface functional layer, based on the deposition of the main functional layer, the CrAl target is opened, nitrogen is introduced at 700-900 sccm, the gas pressure is set to 3-5 Pa, the bias voltage is 60-80 V, the target current is set to 140-160 A, and the coating time is 3500-3700 s.

[0023] Preferably, during the cleaning of the stamping die, the stamping die is ultrasonically cleaned in a cleaning solution and then dried to obtain a cleaned stamping die. The cleaning solution includes acetone.

[0024] Preferably, in the pretreatment of the stamping die, the cleaned stamping die is placed in a vacuum furnace of a multi-arc ion plating device and then evacuated to 3×10 -3Pa, heat to 300~400℃, introduce Ar gas, turn on the bias power supply, set the parameters to 120~150V, IET parameters to 40~60A, tungsten wire current to 50~70A, and perform Ar ion bombardment for 15~30min; then introduce N2, IET parameters to 50~70A, tungsten wire current to 80~100A, bias set to 40~100V, and time for 120min; then clear the target, turn on the Cr target and CrAl target, set the target current to 150A, bias 0V, and target clearing time to 2min to obtain the pretreated stamping die.

[0025] Preferably, in the coating of the stamping die, a multi-arc ion plating method is used to deposit a CrAlN coating on the pretreated stamping die. The deposition of the CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer, and a surface functional layer. The bonding layer is located on the surface of the stamping die, the energy absorption layer is deposited on the bonding layer, and the main functional layer is deposited on the energy absorption layer. The main functional layer can be cyclically deposited for the required number of cycles, and then the surface functional layer is deposited on the outermost layer.

[0026] More preferably, during the deposition of the bonding layer, the Cr target is turned on, the target current is set to 110-130 A, the bias is 700-900 V, 5-15 s, then the bias is 500-700 V, 5-15 s, then the bias is 300-500 V, 5-15 s, then the bias is 200-250 V, 500-700 s.

[0027] More preferably, during the deposition of the energy absorption layer, the Cr target is opened, nitrogen is introduced at 500-600 sccm, the gas pressure is set to 0.4-0.6 Pa, the target current is set to 140-160 A, the bias voltage is 5-15 V, and the deposition time is 7000-8000 s.

[0028] More preferably, during deposition of the primary functional layer, the Cr target is turned off, the CrAl target is turned on, nitrogen is introduced at 700-800 sccm, the pressure is set to 3-5 Pa, the target current is set to 150-250 A, the bias voltage is set to 90-110 V, and the deposition time is 500-700 s. The nitrogen is then turned off, and all other parameters are kept unchanged, for a deposition time of 1000-1500 s. This deposition cycle is repeated multiple times.

[0029] More preferably, the deposition of the main functional layer: turn off the Cr target, turn on the CrAl target, pass nitrogen at 700-800sccm, set the gas pressure to 3-5Pa, set the target current to 150-250A, bias 90-110V, and deposit the CrAlN layer for 500-700s; turn off the CrAl target, turn on the Cr target, pass nitrogen at 500-700sccm, set the gas pressure to 0.4-0.6Pa, set the target current to 140-160A, bias 5-15V, and deposit the CrN layer for 40-60s; turn off the Cr target, turn on the CrAl target, turn off the nitrogen, set the gas pressure to 3-5Pa, set the target current to 150-250A, bias 90-110V, and deposit the CrAl layer for 40-60s; and cyclically deposit the CrN layer and the CrAl layer multiple times. In the present invention, the main functional layer is formed by cyclic deposition of a CrAlN layer, a CrN layer and a CrAl layer, wherein the CrAlN layer is cyclically deposited by a CrN layer and a CrAl layer to form a modulation cycle, and then the CrAlN layer, the CrN layer and the CrAl layer are cyclically deposited in a modulation cycle. The final CrAlN coating prepared by this method of the present invention has high hardness and high elastic modulus.

[0030] More preferably, during the deposition of the surface functional layer, based on the previous deposition step, the CrAl target is opened, nitrogen is introduced at 700-900 sccm, the pressure is set to 3-5 Pa, the bias voltage is 60-80 V, the target current is set to 140-160 A, and the coating time is 3500-3700 s. After the deposition is completed, a CrAlN coating is obtained for the stamping die.

[0031] Currently, TD treatment can achieve the same effect when machining molds on high-strength steel plates. However, due to the high temperature of TD treatment, the mold is easily deformed, and the carburized layer also has certain instability factors. For example, during the treatment process, the mold may crack, the carburized layer may have difficulty penetrating into the steel, and the coarse structure may lead to high brittleness. The method of the present invention successfully overcomes these problems.

[0032] The present invention uses a stamping die as a substrate, and the substrate is hardened by nitriding to improve the bearing capacity of the substrate and avoid the eggshell effect; the first layer in the coating is a bonding layer, which ensures the adhesion of the entire substrate and the coating; the second layer is an energy absorption layer with a relatively loose structure, which can absorb and transfer stress when subjected to high-intensity pressure from the outside, similar to the effect of "sponge elasticity"; the third layer is the main functional layer, which takes on most of the impact stress from the outside; the fourth layer is the surface functional layer, which is a high-hardness surface layer to resist wear and tear with the processed material. Therefore, it has the following beneficial effects: the CrAlN coating prepared by the present invention has high hardness and high elastic modulus. Therefore, the present invention is a method for ultrasonic cleaning of a stamping die with high hardness and high elastic modulus and the preparation of a CrAlN coating on its surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of CrAlN coating;

[0034] Figure 2 is the morphology of CrAlN coating;

[0035] Figure 3 is the hardness diagram;

[0036] Figure 4 is the elastic modulus diagram.

[0037] Reference numerals: 1 - base material, 2 - CrAlN coating of main functional layer, 21 - CrAl layer of main functional layer, 22 - energy absorption layer, 23 - bonding layer, 24 - CrAlN layer, 25 - surface functional layer. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described in detail below with reference to the specific embodiments and the accompanying drawings:

[0039] In the present invention, CrAlN coating is a general concept of thin film coating outside the mold, which is different from the meaning of CrAlN layer. The modulation period in the present invention refers to the cycle period. There are small cycle units in the large cycle units in the present invention. The concept of modulation period is for better distinction. When the small cycle unit is not used, one cycle deposition is equivalent to completing a minimum cycle unit.

[0040] The stamping die used in the embodiment of the present invention is used as the base material, and the material of the stamping die is DC53. The stamping die can also be made of other materials.

[0041] In the embodiment of the present invention, the size of the stamping die is 25×25×6 mm. The stamping die can also be set to other sizes.

[0042] Example 1:

[0043] Ultrasonic cleaning of stamping dies and preparation of CrAlN coating on their surface,

[0044] Cleaning of stamping dies: The stamping dies are ultrasonically cleaned in a cleaning solution and then dried to obtain the cleaned stamping dies. The cleaning solution is acetone.

[0045] Pretreatment of stamping die: Place the cleaned stamping die in a vacuum furnace of multi-arc ion plating equipment and evacuate to 3×10 -3Pa, heat to 400 ° C, introduce Ar gas, turn on the bias power supply, set the parameters to 130V, IET parameters to 50A, tungsten wire current to 60A, and perform Ar ion bombardment for 20 minutes; then introduce N2, IET parameters to 60A, tungsten wire current to 90A, bias voltage to 80V, and time to 120 minutes; then clear the target, turn on the Cr target and CrAl target, set the target current to 150A, bias voltage to 0V, and target clearing time to 2 minutes to obtain the pretreated stamping die.

[0046] Stamping die coating: The pre-treated stamping die is subjected to CrAlN coating deposition by multi-arc ion plating. The deposition of CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer, wherein the bonding layer is located on the surface of the stamping die, the energy absorption layer is deposited on the bonding layer, and the main functional layer is deposited on the energy absorption layer. The main functional layer can be deposited cyclically, and after the required number of cycles, the surface functional layer is deposited on the outermost layer; In the preparation steps of CrAlN coating, the deposition of the bonding layer: turn on the Cr target, set the target current to 120A, bias to 800V, 10s, then bias to 600V, 10s, and then The post-bias was applied at 400V for 10 seconds, followed by a bias of 230V for 600 seconds. The energy absorption layer was deposited by opening the Cr target, introducing 600sccm of nitrogen, setting the pressure to 0.5Pa, setting the target current to 150A, and applying a bias of 10V for 7200 seconds. The primary functional layer was deposited by closing the Cr target, opening the CrAl target, introducing 800sccm of nitrogen, setting the pressure to 4Pa, setting the target current to 200A, and applying a bias of 100V for 600 seconds. The nitrogen was then closed, keeping all other parameters unchanged, for 1200 seconds. The primary functional layer was deposited once again. The surface functional layer was deposited by opening the CrAl target, introducing 800sccm of nitrogen, setting the pressure to 4Pa, applying a bias of 70V, and setting the target current to 150A. The deposition time was 3600 seconds. After completion of the deposition, the CrAlN coating for the stamping die was obtained.

[0047] The schematic diagram of the CrAlN coating of the stamping die prepared in this embodiment is shown in FIG. Figure 1 shown.

[0048] Example 2:

[0049] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment is different in that, in the coating of the stamping die, the main functional layer is cyclically deposited twice.

[0050] Example 3:

[0051] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment is different in that, in the coating of the stamping die, the main functional layer is cyclically deposited three times.

[0052] Example 4:

[0053] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment is different in that, in the coating of the stamping die, the main functional layer is cyclically deposited four times.

[0054] Example 5:

[0055] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment is different in that, in the coating of the stamping die, the main functional layer is cyclically deposited 5 times.

[0056] Example 6:

[0057] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment is different in that, in the coating of the stamping die, the main functional layer is cyclically deposited 6 times.

[0058] Example 7:

[0059] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment is different in that, in the coating of the stamping die, the main functional layer is cyclically deposited 7 times.

[0060] Example 8:

[0061] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment is different in that, in the coating of the stamping die, the main functional layer is cyclically deposited 9 times.

[0062] Example 9:

[0063] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 1, this embodiment differs from Example 1 in the coating of the stamping die.

[0064] Coating of stamping die: The pre-treated stamping die is subjected to CrAlN coating deposition by multi-arc ion plating. The deposition of CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer, wherein the bonding layer is located on the surface of the stamping die, the energy absorption layer is deposited on the bonding layer, and the main functional layer is deposited on the energy absorption layer. The main functional layer can be deposited cyclically, and after the required number of cycles, the surface functional layer is deposited on the outermost layer; in the preparation steps of CrAlN coating, the deposition of bonding layer: turn on the Cr target, set the target current to 120A, bias to 800V, 10s, then bias to 600V, 10s, then bias to 400V, 10s, then bias to 230V, 600s; the deposition of energy absorption layer: turn on the Cr target, introduce 600sccm of nitrogen, and set the gas pressure to 0.5Pa , set the target current to 150A, the bias to 10V, and the time to deposit the CrN layer: turn off the Cr target, turn on the CrAl target, pass 800sccm of nitrogen, set the gas pressure to 4Pa, set the target current to 200A, the bias to 100V, and the time to deposit the CrAlN layer for 600s; turn off the CrAl target, turn on the Cr target, pass 600sccm of nitrogen, set the gas pressure to 0.5Pa, set the target current to 150A, the bias to 10V, and the time to deposit the CrN layer for 50s; turn off the Cr target, turn on the CrAl target, turn off the nitrogen, set the gas pressure to 4Pa, set the target current to 200A, the bias to 100V, and the time to deposit the CrAl layer for 50s; cycle the deposition of the CrN layer and the CrAl layer 12 times. The main functional layer was deposited once in a cycle. For the surface functional layer, following the previous deposition step, the CrAl target was opened, nitrogen gas was introduced at 800 sccm, the pressure was set to 4 Pa, the bias voltage was 70 V, the target current was set to 150 A, and the deposition time was 3600 s. After the deposition was completed, the CrAlN coating on the stamping die was obtained.

[0065] Example 10:

[0066] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 3, this embodiment differs in the coating of the stamping die.

[0067] Coating of stamping die: The pre-treated stamping die is subjected to CrAlN coating deposition by multi-arc ion plating. The deposition of CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer, wherein the bonding layer is located on the surface of the stamping die, the energy absorption layer is deposited on the bonding layer, and the main functional layer is deposited on the energy absorption layer. The main functional layer can be deposited cyclically, and after the required number of cycles, the surface functional layer is deposited on the outermost layer; in the preparation steps of CrAlN coating, the deposition of bonding layer: turn on the Cr target, set the target current to 120A, bias to 800V, 10s, then bias to 600V, 10s, then bias to 400V, 10s, then bias to 230V, 600s; the deposition of energy absorption layer: turn on the Cr target, introduce 600sccm of nitrogen, and set the gas pressure to 0.5Pa , set the target current to 150A, the bias to 10V, and the time to deposit the CrN layer: turn off the Cr target, turn on the CrAl target, pass 800sccm of nitrogen, set the gas pressure to 4Pa, set the target current to 200A, the bias to 100V, and the time to deposit the CrAlN layer for 600s; turn off the CrAl target, turn on the Cr target, pass 600sccm of nitrogen, set the gas pressure to 0.5Pa, set the target current to 150A, the bias to 10V, and the time to deposit the CrN layer for 50s; turn off the Cr target, turn on the CrAl target, turn off the nitrogen, set the gas pressure to 4Pa, set the target current to 200A, the bias to 100V, and the time to deposit the CrAl layer for 50s; cycle the deposition of the CrN layer and the CrAl layer 12 times. The main functional layer was deposited three times in a cycle. For the surface functional layer, based on the previous deposition step, the CrAl target was opened, nitrogen gas was introduced at 800 sccm, the pressure was set to 4 Pa, the bias voltage was 70 V, the target current was set to 150 A, and the deposition time was 3600 s. After the deposition was completed, the CrAlN coating on the stamping die was obtained.

[0068] Example 11:

[0069] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 5, this embodiment differs in the coating of the stamping die.

[0070] Coating of stamping die: The pre-treated stamping die is subjected to CrAlN coating deposition by multi-arc ion plating. The deposition of CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer, wherein the bonding layer is located on the surface of the stamping die, the energy absorption layer is deposited on the bonding layer, and the main functional layer is deposited on the energy absorption layer. The main functional layer can be deposited cyclically, and after the required number of cycles, the surface functional layer is deposited on the outermost layer; in the preparation steps of CrAlN coating, the deposition of bonding layer: turn on the Cr target, set the target current to 120A, bias to 800V, 10s, then bias to 600V, 10s, then bias to 400V, 10s, then bias to 230V, 600s; the deposition of energy absorption layer: turn on the Cr target, introduce 600sccm of nitrogen, and set the gas pressure to 0.5Pa , set the target current to 150A, the bias to 10V, and the time to deposit the CrN layer: turn off the Cr target, turn on the CrAl target, pass 800sccm of nitrogen, set the gas pressure to 4Pa, set the target current to 200A, the bias to 100V, and the time to deposit the CrAlN layer for 600s; turn off the CrAl target, turn on the Cr target, pass 600sccm of nitrogen, set the gas pressure to 0.5Pa, set the target current to 150A, the bias to 10V, and the time to deposit the CrN layer for 50s; turn off the Cr target, turn on the CrAl target, turn off the nitrogen, set the gas pressure to 4Pa, set the target current to 200A, the bias to 100V, and the time to deposit the CrAl layer for 50s; cycle the deposition of the CrN layer and the CrAl layer 12 times. The main functional layer was deposited five times in a cycle. For the surface functional layer, based on the previous deposition step, the CrAl target was opened, nitrogen was introduced at 800 sccm, the pressure was set to 4 Pa, the bias voltage was 70 V, the target current was set to 150 A, and the deposition time was 3600 s. After the deposition was completed, the CrAlN coating on the stamping die was obtained.

[0071] Comparative Example 1:

[0072] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 3, this embodiment differs in the coating of the stamping die.

[0073] Coating of stamping die: CrAlN coating is deposited on the pretreated stamping die using multi-arc ion plating method. The deposition of the CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer, wherein the bonding layer is located on the surface of the stamping die, the energy absorption layer is deposited on the bonding layer, and the main functional layer is deposited on the energy absorption layer. The main functional layer can be deposited cyclically, and after deposition according to the required number of cycles, the surface functional layer is deposited on the outermost layer; in the preparation step of the CrAlN coating, the deposition of the bonding layer: turn on the Cr target, set the target current to 120A, the bias to 800V, 10s, then the bias to 600V, 10s, then the bias to 400V, 10s, then the bias to 230V, 600s; the deposition of the energy absorption layer: turn on the Cr target, introduce 600sccm of nitrogen, set the gas pressure to 0.5Pa, set the target current to 150A, the bias to 10V, and the time to 1800s. The main functional layer was deposited three times in a cycle. For the surface functional layer, based on the previous deposition step, the CrAl target was opened, nitrogen gas was introduced at 800 sccm, the pressure was set to 4 Pa, the bias voltage was 70 V, the target current was set to 150 A, and the deposition time was 3600 s. After the deposition was completed, the CrAlN coating on the stamping die was obtained.

[0074] Comparative Example 2:

[0075] Ultrasonic cleaning of a stamping die and preparation of a CrAlN coating on its surface. Compared with Example 3, this embodiment differs in the coating of the stamping die.

[0076] Coating of stamping die: CrAlN coating is deposited on the pretreated stamping die using multi-arc ion plating method. The deposition of the CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer, wherein the bonding layer is located on the surface of the stamping die, the energy absorption layer is deposited on the bonding layer, and the main functional layer is deposited on the energy absorption layer. The main functional layer can be deposited cyclically, and after deposition according to the required number of cycles, the surface functional layer is deposited on the outermost layer; in the preparation step of the CrAlN coating, the deposition of the bonding layer: turn on the Cr target, set the target current to 120A, the bias to 800V, 10s, then the bias to 600V, 10s, then the bias to 400V, 10s, then the bias to 230V, 600s; the deposition of the energy absorption layer: turn on the Cr target, introduce 600sccm of nitrogen, set the gas pressure to 0.5Pa, set the target current to 150A, the bias to 10V, and the time to 1800s. The main functional layer was deposited five times in a cycle. For the surface functional layer, based on the previous deposition step, the CrAl target was opened, nitrogen was introduced at 800 sccm, the pressure was set to 4 Pa, the bias voltage was 70 V, the target current was set to 150 A, and the deposition time was 3600 s. After the deposition was completed, the CrAlN coating on the stamping die was obtained.

[0077] Test example:

[0078] Electron microscopy characterization

[0079] The surface morphology of the CrAlN coating of the stamping die prepared in Example 5 of the present invention is as follows: Figure 2 As shown, the coating surface is slightly rough, and there are particles and small holes on the surface of the coating.

[0080] Hardness characterization

[0081] The hardness of the CrAlN coating of the stamping die prepared by the method of the present invention is as follows: Figure 3As shown, wherein S1 is Example 1, S2 is Example 2, S3 is Example 3, S4 is Example 4, S5 is Example 5, S6 is Example 6, S7 is Example 7, S8 is Example 8, S9 is Example 9, S10 is Example 10, S11 is Example 11, D1 is Comparative Example 1, and D2 is Comparative Example 2. The present invention first deposits a bonding layer on the stamping die, and the bonding layer is a Cr layer; then deposits an energy absorbing layer on the bonding layer, and the energy absorbing layer is a CrN layer; then deposits a main functional layer on the energy absorbing layer, and the main functional layer is composed of a cyclic deposition of a CrAlN layer and a CrAl layer, and the deposition time of the CrAl layer is twice the deposition time of the CrAlN layer, and then the CrAlN layer and the CrAl layer are cyclically deposited. The ring deposition is carried out for at least two cycles, and then the surface functional layer is deposited on the outermost layer. The surface functional layer is a CrAlN layer. The CrAlN coating is obtained according to the above deposition method. In the coating prepared by the method of the present invention, the stamping die is used as the substrate, and the substrate is hardened by nitriding to improve the bearing capacity of the substrate and avoid the eggshell effect; the first layer in the coating is a bonding layer, which ensures the adhesion of the entire substrate and the coating; the second layer is an energy absorption layer with a relatively loose structure. When high-intensity pressure comes from the outside, it can absorb and transfer the stress, which is similar to the effect of "sponge elasticity"; the third layer is the main functional layer, which takes on most of the impact stress from the outside; the fourth layer is the surface functional layer, which is a high-hardness surface layer to resist wear with the processed material. The combination of the main functional layer and the surface functional layer in the present invention makes the hardness of the CrAlN coating higher and improves the performance of the CrAlN coating, indicating that the hierarchical structure of the main functional layer and the surface functional layer have excellent bonding performance. Through testing, it is found that when the CrAlN layer and the CrAl layer in the main functional layer are cyclically deposited for five cycles, the hardness of the obtained CrAlN coating is greatly improved. When the CrAlN layer and the CrAl layer in the main functional layer are cyclically deposited for more than five cycles, the bonding effect between the main functional layer and the surface functional layer becomes weak, resulting in a decrease in the hardness of the CrAlN coating. When studying the main functional layer, after the CrAlN layer is deposited, a CrN layer and a CrAl layer can be deposited, and then the CrN layer and the CrAl layer are cyclically deposited. The deposition time of the CrN layer and the CrAl layer in the cyclic deposition is relatively short. After the total deposition time of the CrN layer and the CrAl layer reaches a certain time, the deposition method of the CrAlN layer, the CrN layer and the CrAl layer is cyclically deposited to obtain a CrAlN coating. The obtained CrAlN coating has higher hardness and better effect. When only the CrAl layer is deposited as the main functional layer, the hardness of the CrAlN coating formed by the bonding layer, the energy absorption layer, the main functional layer of the CrAl layer and the surface functional layer is weakened.

[0082] Elastic modulus characterization

[0083] The elastic modulus of the CrAlN coating of the stamping die prepared by the method of the present invention is as follows: Figure 4 As shown, wherein S1 is Example 1, S2 is Example 2, S3 is Example 3, S4 is Example 4, S5 is Example 5, S6 is Example 6, S7 is Example 7, S8 is Example 8, S9 is Example 9, S10 is Example 10, S11 is Example 11, D1 is Comparative Example 1, and D2 is Comparative Example 2. The present invention first deposits a bonding layer on the stamping die, and the bonding layer is a Cr layer; then deposits an energy absorbing layer on the bonding layer, and the energy absorbing layer is a CrN layer; then deposits a main functional layer on the energy absorbing layer, and the main functional layer is composed of a cyclic deposition of a CrAlN layer and a CrAl layer, and the deposition time of the CrAl layer is twice the deposition time of the CrAlN layer, and then the CrAlN layer and the CrAl layer are cyclically deposited. The ring deposition is carried out for at least two cycles, and then the surface functional layer is deposited on the outermost layer. The surface functional layer is a CrAlN layer. The CrAlN coating is obtained according to the above deposition method. In the coating prepared by the method of the present invention, the stamping die is used as the substrate, and the substrate is hardened by nitriding to improve the bearing capacity of the substrate and avoid the eggshell effect; the first layer in the coating is a bonding layer, which ensures the adhesion of the entire substrate and the coating; the second layer is an energy absorption layer with a relatively loose structure. When high-intensity pressure comes from the outside, it can absorb and transfer the stress, which is similar to the effect of "sponge elasticity"; the third layer is the main functional layer, which takes on most of the impact stress from the outside; the fourth layer is the surface functional layer, which is a high-hardness surface layer to resist wear with the processed material. The combination of the main functional layer and the surface functional layer in the present invention makes the elastic modulus of the CrAlN coating higher and improves the performance of the CrAlN coating, indicating that the hierarchical structure of the main functional layer and the surface functional layer have excellent bonding performance. Through testing, it is found that when the CrAlN layer and the CrAl layer in the main functional layer are cyclically deposited for five cycles, the elastic modulus of the obtained CrAlN coating is greatly improved. When the cyclic deposition of the CrAlN layer and the CrAl layer in the main functional layer exceeds five cycles, the bonding effect between the main functional layer and the surface functional layer weakens, resulting in a decrease in the elastic modulus of the CrAlN coating. When studying the main functional layer, after the CrAlN layer is deposited, a CrN layer and a CrAl layer can be deposited, and then the CrN layer and the CrAl layer are cyclically deposited. The deposition time of the CrN layer and the CrAl layer in the cyclic deposition is relatively short. After the total deposition time of the CrN layer and the CrAl layer reaches a certain time, the deposition is then cyclically deposited according to the deposition method of the CrAlN layer, the CrN layer and the CrAl layer to obtain a CrAlN coating. The obtained CrAlN coating has a higher elastic modulus and better effect. When only the CrAl layer is deposited as the main functional layer, the elastic modulus of the CrAlN coating formed by the bonding layer, energy absorption layer, main functional layer of the CrAl layer and surface functional layer is weakened.

[0084] The above embodiments are intended to illustrate the present invention only and are not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the scope of patent protection of the present invention shall be defined by the claims.

Claims

1. A CrAlN coating for a mold, comprising: A substrate material, and a CrAlN coating bonded to the substrate material; The CrAlN coating includes a bonding layer, an energy absorption layer, a main functional layer and a surface functional layer. The bonding layer is bonded to the base material, the energy absorption layer is bonded to the bonding layer, and the main functional layer is bonded to the energy absorption layer. The main functional layer contains a CrAlN layer and a CrAl layer. The main functional layer is composed of 3-9 groups of cyclic layers; a single group of cyclic layers includes a repeating layer composed of a CrAlN layer and a CrAl layer; and the surface functional layer is bonded to the main functional layer. The thickness of the CrAlN coating is greater than 6.4 μm; the thickness of the energy absorption layer is 2-4 μm; the thickness of the surface functional layer is 1-2 μm; and the thickness of the main functional layer is 3-6 μm. The main functional layer is deposited by a multi-arc ion plating method. During the deposition of the main functional layer, the Cr target is turned off, the CrAl target is turned on, 700-800 sccm of nitrogen is introduced, the pressure is set to 3-5 Pa, the target current is set to 150-250 A, the bias voltage is 90-110 V, and the time is 500-700 s; the nitrogen is turned off, and the other setting parameters are kept unchanged for 1000-1500 s; the main functional layer is cyclically deposited 3-9 times; The base material is a stamping die.

2. The CrAlN coating for a mold according to claim 1, wherein: The thickness of the CrAlN coating is greater than 10 μm.

3. A method for preparing a CrAlN coating on the surface of a stamping die after ultrasonic cleaning, comprising: The CrAlN coating according to claim 1 is deposited on the mold by a multi-arc ion plating method, and the mold is ultrasonically cleaned.

4. The method for preparing a CrAlN coating on a stamping die surface after ultrasonic cleaning according to claim 3, wherein: Deposition of the bonding layer: turn on the Cr target, set the target current to 110-130A, bias to 700-900V, 5-15s, then bias to 500-700V, 5-15s, then bias to 300-500V, 5-15s, then bias to 200-250V, 500-700s.

5. The method for preparing a CrAlN coating on a stamping die surface after ultrasonic cleaning according to claim 3, wherein: Deposition of the energy absorption layer: open the Cr target, introduce nitrogen at 500-600 sccm, set the gas pressure to 0.4-0.6 Pa, set the target current to 140-160 A, the bias voltage to 5-15 V, and perform the deposition for 7000-8000 s.

6. The method for preparing a CrAlN coating on a stamping die surface after ultrasonic cleaning according to claim 3, wherein: In the deposition of the surface functional layer, on the basis of the deposition of the main functional layer, the CrAl target is opened, 700-900 sccm of nitrogen is introduced, the gas pressure is set to 3-5 Pa, the bias voltage is 60-80 V, the target current is set to 140-160 A, and the coating time is 3500-3700 s.

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