CN103789723B - A kind of Cr/CrN/ (Ti, Al, Si, Cr) N rigid composite coating and preparation method thereof - Google Patents

Abstract

The preparation method of the Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating disclosed by the present invention includes pretreatment, heating, plasma cleaning, preparation of Cr adhesion layer, preparation of CrN transition layer and preparation of (Ti , Al, Si, Cr) N wear-resistant layer and other steps. Since the preparation method provided by the present invention adopts the plasma-enhanced intermediate-frequency reactive magnetron sputtering technology, the ionization rate of the target is greatly improved, and the surface nanohardness of the prepared composite hard coating can reach more than 34GPa. The base bonding force level is HF1-HF2 of the German standard VDI3198, so it is especially suitable for making coatings for high-speed dry cutting stainless steel, iron-based superalloys, high-strength structural steel and wear-resistant cast steel tools, and the coating process is simple and more Suitable for industrial production.

Description

A kind of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating and preparation method thereof

technical field

The invention belongs to the technical field of tool surface composite coating material and its preparation, and in particular relates to a Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating and a preparation method thereof. The coating nano The hardness can reach more than 34Gpa, and the bonding strength of the film base is HF1~HF2 (German standard VDI3198). It is especially suitable as a surface coating for high-speed dry cutting stainless steel, iron-based superalloys, high-strength structural steel and wear-resistant cast steel tools.

Background technique

With the rapid development of industry, tools with coated surfaces are widely used in the field of material cutting. Studies have shown that the coating tool has the characteristics of high hardness, wear resistance and strong oxidation resistance, which can significantly improve the service life of the tool. However, with the emergence and development of high-speed cutting and dry cutting, the usual TiN and TiAlN coatings have been difficult to meet the user's requirements for tool coating service life.

In order to improve the service life of tool coatings, the new TiAlSiN coatings and TiAlCrN coatings developed in recent years have been successively applied to the field of cutting tools, among which the structure of TiAlSiN coatings (HaoDu, HaiboZhao, JiXiong, et al. (2013)60-66.) is the amorphous Si ₃ N ₄ structure wrapped around nano-TiAlN grains, so the coating can obtain very high hardness (46Gpa) and oxidation resistance, but with the increase of hardness, the coating The internal stress also increases accordingly, resulting in poor bonding between the coating and the tool. Therefore, the most common failure form of the TiAlSiN coating during the cutting process is the coating shedding failure. TiAlCrN coating (GS Fox-Rabinovich. Surface and Coatings Technology 200 (2005) 1804-1813), although it has high lubricity and oxidation resistance, its structure is non-nanocrystalline and its hardness is low (30Gpa). produce wear and tear.

Contents of the invention

The object of the present invention is to provide a method for preparing a Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating for the problems existing in the TiAlSiN coating and the TiAlCrN coating.

Another object of the present invention is to provide a Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating with excellent hardness and bonding force prepared by the above method.

The preparation method of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating provided by the present invention, its processing steps and conditions are as follows:

1) After installing the tool into the coating chamber, first vacuum the coating chamber to at least 5.0×10 ^-3 Pa, and then pass in argon to make the total pressure in the coating chamber 3.0×10 ^-1 ~ 4.5×10 ^-1 Pa, Turn on the hot cathode ion column arc so that the current is 140-180A, and heat the tool for 40-150 minutes;

2) Under the protection of argon gas with a pressure of 1.5×10 ^-1 ~ 2.0×10 ^-1 Pa, control the tool DC bias voltage -100 ~ -200V, pulse bias voltage -500 ~ -800V, and then use a current of 110 ~ 160A The plasma generated by the hot cathode ion column arc bombards and cleans the tool surface for 15-50 minutes;

3) Under the protection of argon gas of 8.0×10 ^-2 ~ 1.5×10 ^-1 Pa, heat the Cr ingot with a hot cathode ion column arc with a current of 180 ~ 220A to evaporate it, and plate the tool for 5 ~ 10 minutes. A layer of Cr adhesion layer is formed on the surface, and then nitrogen gas is passed through, and the flow ratio of argon gas and nitrogen gas is 1:1.5~3 and the pressure of 3.0×10 ^-1 ~4.5×10 ^-1 Pa is plated for 15~ 30min, make the surface of Cr adhesion layer form one deck CrN transition layer;

4) Continue to feed the mixed gas of argon and nitrogen into the coating chamber according to the flow ratio of 1:1.5~3, so that the pressure is 3.0×10 ^-1 ~4.5×10 ^-1 Pa, and adjust the DC bias voltage of the tool to - 40～-70V, the hot cathode ion column arc current is adjusted to 100～110A, and at the same time turn on the control power supply of the intermediate frequency reaction magnetron sputtering, and keep the current of the TiAlSiCr target at 4.0～7.0A for 120～180min, so that the tool A layer of (Ti, Al, Si, Cr)N coating is formed on the surface of the CrN transition layer, and then cooled naturally.

The TiAlSiCr target used in the above method is a TixAlySizCr1-x-y-z composite alloy target, and its titanium-aluminum-silicon-chromium atomic ratio is 50～70:20～30:1～7:1～5, preferably 65～70:20～28:1～ 6: 1~4, the purity is 99.99%.

In step 3) of the above method, the pressure for plating the Cr adhesion layer is preferably 8.0×10 ^-2 ~ 1.2×10 ^-1 Pa, the current of the hot cathode ion column arc is preferably 200-220A, and the plating time is preferably 5-7 minutes.

In step 3) of the above method, the flow ratio of argon and nitrogen for plating the CrN transition layer is preferably 1:1.5~2.5, the pressure is preferably 4.0×10 ^-1 ~4.5×10 ^-1 Pa, and the plating time is preferably 15~25min.

In step 4) of the above method, the flow ratio of argon gas and nitrogen gas for plating (Ti, Al, Si, Cr)N coating is preferably 1:1.5~2.5, and the arc current of hot cathode ion column is preferably 105~110A, and the current of TiAlSiCr target Preferably 5.0-7.0A, and the plating time is preferably 120-160min.

There are four TiAlSiCr targets described in the above method, and they are placed on the inner wall of the coating chamber in a pairwise opposite manner.

The Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating prepared by the above method provided by the present invention has three layers, which are successively Cr adhesion layer, CrN The transition layer and (Ti, Al, Si, Cr) N coating have a nanohardness ≥ 34Gpa, and the level of bonding force with the tool substrate reaches HF1-HF2 of the German standard VDI3198.

The thickness of the Cr adhesion layer in the above composite coating is 50-200nm, the thickness of the CrN transition layer is 100-500nm, the thickness of the (Ti,Al,Si,Cr)N coating is 2-5μm, and its structure is nanometer Crystal structure, the diffraction intensity of TiN (111) plane in X-ray diffraction is <100, and the diffraction intensity of TiN (200) plane is ≥300.

Compared with the prior art, the present invention has the following advantages:

1) Since the plasma-enhanced intermediate-frequency reactive magnetron sputtering technology is adopted in the preparation method provided by the present invention, the ionization rate of the target is greatly improved, which not only makes the obtained coating structure more uniform and dense, but also has a good contact with the substrate. The knives have a higher binding force.

2) Since the TixAlySizCr1-x-y-z composite alloy target with a purity of 99.99% is used in the preparation method provided by the present invention for sputter coating, the stability of the obtained coating performance is guaranteed, and at the same time, the coating is reduced. The complexity of the layer process is more suitable for industrial production.

3) Since the composite coating provided by the present invention includes a Cr adhesion layer, a CrN transition layer and a (Ti, Al, Si, Cr)N coating, and the Cr adhesion layer not only has better compatibility with the substrate, And it also has good diffusivity, which can effectively improve the bonding force between the coating and the substrate tool; the CrN transition layer can reduce the thermal expansion coefficient between the Cr adhesion layer and the (Ti, Al, Si, Cr)N coating. difference, reduce the stress between layers, so that the coating can obtain higher strength; while (Ti, Al, Si, Cr) N coating has higher hardness and lower elastic modulus, which can make the coating The layer has better mechanical properties, so that the nanohardness of the composite coating can be ≥ 34Gpa, which has better wear resistance, and at the same time can make the bonding force level with the tool matrix reach HF1-HF2 of the German standard VDI3198, and the service life longer.

Description of drawings

Fig. 1 is a scanning electron microscope image of the fracture surface of the Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating prepared in Example 4 of the present invention.

FIG. 2 is a scanning electron microscope image of the fracture morphology of the Ti/TiN/TiAlN coating prepared in Comparative Example 1.

3 is a scanning electron microscope image of the fracture surface of the Ti/TiAlSiN coating prepared in Comparative Example 2.

4 is a scanning electron microscope image of the fracture surface of the Ti/TiN/TiAlCrN coating prepared in Comparative Example 3.

Fig. 5 is a schematic diagram of the bonding force between the Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating and the cutting tool substrate prepared in Example 4 of the present invention.

6 is a schematic diagram of the bonding force between the Ti/TiN/TiAlN coating prepared in Comparative Example 1 and the tool substrate.

7 is a schematic diagram of the bonding force between the Ti/TiAlSiN coating prepared in Comparative Example 2 and the tool substrate.

8 is a schematic diagram of the bonding force between the Ti/TiN/TiAlCrN coating prepared in Comparative Example 3 and the tool substrate.

Fig. 9 is an XRD spectrum of the Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating prepared in Example 4 of the present invention.

Detailed ways

The present invention will be further described below through specific examples, but the protection content of the present invention is not limited to the following examples.

It is worth noting that 1) the TiAlSiCr targets used in the following examples were customized by the applicant at Antai Technology Co., Ltd. 2) The coating hardness of the tool products prepared in the following examples and comparative examples was tested using a nanohardness tester MTS Systems Corp., Oak Ridge, TN, USA, according to the conditions of surface approach speed of 10nm/s, minimum indentation depth of 200nm, and maximum indentation depth of 300nm of. 3) The bonding force grades of the coatings prepared in the following examples and comparative examples were tested with a Rockwell hardness tester HR-150A, under a HRC diamond indenter with a cone angle of 120° and a load of 60Kg. 4) The thickness of each layer of the composite coating was observed and tested by a scanning electron microscope (S300-N, Hitachi, Japan).

Example 1

1) Put the cemented carbide taps that have been ^degreased , sand blasted and ultrasonically cleaned by conventional methods into the coating chamber. The total pressure is 3.0×10 ^-1 Pa, the hot cathode ion column arc is turned on so that the current is 150A, and the tool is heated for 150min;

2) Under the protection of argon gas with a pressure of 1.8×10 ^-1 Pa, the DC bias voltage of the tool is controlled to -200V, the pulse bias voltage is -700V, and then the plasma generated by the hot cathode ion column arc with a current of 110A is used to treat the surface of the tool Bombardment cleaning for 30 minutes;

3) Under the protection of argon gas with a pressure of 8.0×10 ^-2 Pa, heat the Cr ingot with a hot cathode ion column arc with a current of 200A to evaporate it, and plate the tool for 10 minutes to form a layer of Cr adhesion on the surface layer, and then pass in a mixed gas of argon and nitrogen with a flow ratio of 1:1.5, and plate at a pressure of 4.0×10 ^-1 Pa for 15 minutes to form a CrN transition layer on the surface of the Cr adhesion layer;

4) According to the flow ratio of 1:3, the mixed gas of argon and nitrogen is introduced into the coating chamber, and the pressure is kept at 3.0×10 ^-1 Pa, and the DC bias voltage of the tool is adjusted to -40V, and the arc current of the hot cathode ion column is adjusted. At the same time, turn on the control power supply of intermediate frequency reactive magnetron sputtering to sputter the composite alloy target of Ti:Al:Si:Cr=70:28:1:1, and keep the current of TiAlSiCr target at 5.0A for plating After 120 minutes, a layer of (Ti, Al, Si, Cr)N coating is formed on the surface of the CrN transition layer of the tool, and then cooled naturally.

The hard alloy tap is coated with Cr/CrN/(Ti,Al,Si,Cr)N composite coating, and the hardness measured is 34-36Gpa, and the Cr adhesion layer, CrN transition layer and (Ti,Al,Si, The thicknesses of the Cr)N coatings are 100nm, 100nm, and 2.3μm, respectively, and the bonding force between the coating and the tool substrate is HF2.

Example 2

1) Put the cemented carbide turning tool after degreasing, sandblasting and ultrasonic cleaning by conventional methods into the coating chamber, first vacuum the coating chamber to 5.0×10 ^-3 Pa, and then pass in argon gas to make the coating The total indoor pressure is 4.0×10 ^-1 Pa, the hot cathode ion column arc is turned on so that the current is 160A, and the tool is heated for 100min;

2) Under the protection of argon gas with a pressure of 1.5×10 ^-1 Pa, the DC bias voltage of the tool is controlled to -150V, the pulse bias voltage is -600V, and then the plasma generated by the hot cathode ion column arc with a current of 120A is used to treat the surface of the tool Bombardment cleaning for 40 minutes;

3) Under the protection of argon gas with a pressure of 1.0×10 ^-1 Pa, heat the Cr ingot with a hot cathode ion column arc with a current of 180A to evaporate it, and plate the tool for 6 minutes to form a layer of Cr adhesion on the surface layer, and then pass in a mixed gas of argon and nitrogen with a flow ratio of 1:3, and plate at a pressure of 3.0×10 ^-1 Pa for 20 minutes, so that a layer of CrN transition layer is formed on the surface of the Cr adhesion layer;

4) According to the flow ratio of 1:2, the mixed gas of argon and nitrogen is introduced into the coating chamber, and the pressure is kept at 4.0×10 ^-1 Pa, and the DC bias voltage of the tool is adjusted to -50V, and the arc current of the hot cathode ion column is adjusted. At the same time, turn on the control power supply of the intermediate frequency reactive magnetron sputtering to sputter the composite alloy target of Ti:Al:Si:Cr=60:30:6:4, and keep the current of the TiAlSiCr target at 4.0A. After 140 minutes, a layer of (Ti, Al, Si, Cr)N coating is formed on the surface of the CrN transition layer of the tool, and then cooled naturally.

The hard alloy turning tool is coated with Cr/CrN/(Ti,Al,Si,Cr)N composite coating, and the hardness measured is 38-40Gpa. The Cr adhesion layer, CrN transition layer and (Ti,Al,Si ,Cr)N coating thicknesses are 60nm, 200nm, 2.5μm respectively, and the bonding force level between the coating and the tool substrate is HF1.

Example 3

1) Put the cemented carbide drill bits that have been ^degreased , sand blasted and ultrasonically cleaned by conventional methods into the coating chamber. The total pressure is 3.0×10 ^-1 Pa, the hot cathode ion column arc is turned on so that the current is 140A, and the tool is heated for 40 minutes;

2) Under the protection of argon gas with a pressure of 1.5×10 ^-1 Pa, the DC bias voltage of the tool is controlled to -100V, the pulse bias voltage is -500V, and then the plasma generated by the hot cathode ion column arc with a current of 110A is used to treat the surface of the tool Bombardment cleaning for 15 minutes;

3) Under the protection of argon gas with a pressure of 1.2×10 ^-1 Pa, heat the Cr ingot with a hot cathode ion column arc with a current of 210A to evaporate it, and plate the tool for 7 minutes to form a layer of Cr adhesion on the surface layer, and then pass in a mixed gas of argon and nitrogen with a flow ratio of 1:2.5, and plate at a pressure of 4.2×10 ^-1 Pa for 30 minutes, so that a layer of CrN transition layer is formed on the surface of the Cr adhesion layer;

4) According to the flow ratio of 1:1.5, the mixed gas of argon and nitrogen is introduced into the coating chamber, and the pressure is maintained at 3.5×10 ^-1 Pa, and the DC bias voltage of the tool is adjusted to -60V, and the arc current of the hot cathode ion column is adjusted. At the same time, turn on the control power supply of the intermediate frequency reactive magnetron sputtering to sputter the composite alloy target of Ti:Al:Si:Cr=70:20:5:5, and keep the current of the TiAlSiCr target at 7.0A for plating After 160 minutes, a layer of (Ti, Al, Si, Cr)N coating is formed on the surface of the CrN transition layer of the tool, and then cooled naturally.

The hard alloy drill bit is coated with Cr/CrN/(Ti,Al,Si,Cr)N composite coating, and the measured hardness is 32-35Gpa. The Cr adhesion layer, CrN transition layer and (Ti,Al,Si, The thicknesses of the Cr)N coatings are 89nm, 500nm, and 5.0μm, respectively, and the bonding force between the coating and the tool substrate is HF1.

Example 4

1) Put the cemented carbide milling cutter after degreasing, sandblasting and ultrasonic cleaning by conventional methods into the coating chamber, first vacuum the coating chamber to 5.0×10 ^-3 Pa, and then pass in argon gas to make the coating The total indoor pressure is 4.5×10 ^-1 Pa, the hot cathode ion column arc is turned on so that the current is 180A, and the tool is heated for 80min;

2) Under the protection of argon gas with a pressure of 2.0×10 ^-1 Pa, the DC bias voltage of the tool is controlled to -200V, the pulse bias voltage is -800V, and then the plasma generated by the hot cathode ion column arc with a current of 160A is used to treat the surface of the tool Bombardment cleaning for 50 minutes;

3) Under the protection of argon gas with a pressure of 1.5×10 ^-1 Pa, heat the Cr ingot with a hot cathode ion column arc with a current of 220A to evaporate it, and plate the tool for 5 minutes to form a layer of Cr adhesion on the surface layer, and then pass in a mixed gas of argon and nitrogen with a flow ratio of 1:2.0, and plate at a pressure of 4.5×10 ^-1 Pa for 25 minutes, so that a layer of CrN transition layer is formed on the surface of the Cr adhesion layer;

4) According to the flow ratio of 1:2.5, the mixed gas of argon and nitrogen is introduced into the coating chamber, and the pressure is kept at 4.5×10 ^-1 Pa, and the DC bias voltage of the tool is adjusted to -70V, and the arc current of the hot cathode ion column is adjusted. At the same time, turn on the control power supply of intermediate frequency reactive magnetron sputtering to sputter the composite alloy target of Ti:Al:Si:Cr=65:25:7:3, and keep the current of TiAlSiCr target at 6.0A for plating After 180 minutes, a layer of (Ti, Al, Si, Cr)N coating is formed on the surface of the CrN transition layer of the tool, and then cooled naturally.

The hard alloy milling cutter is coated with Cr/CrN/(Ti,Al,Si,Cr)N composite coating, and the measured hardness is 34-41Gpa. The Cr adhesion layer, CrN transition layer and (Ti,Al,Si ,Cr)N coating thicknesses are 50nm, 350nm, 2.0μm respectively, and the bonding force level between the coating and the tool substrate is HF1.

Comparative example 1

1) Put the cemented carbide milling cutter after degreasing, sandblasting and ultrasonic cleaning by conventional methods into the coating chamber, first vacuum the coating chamber to 5.0×10 ^-3 Pa, and then pass in argon gas to make the coating The total indoor pressure is 4.5×10 ^-1 Pa, the hot cathode ion column arc is turned on so that the current is 180A, and the tool is heated for 80min;

2) Under the protection of argon gas with a pressure of 2.0×10 ^-1 Pa, the DC bias voltage of the tool is controlled to -200V, the pulse bias voltage is -800V, and then the plasma generated by the hot cathode ion column arc with a current of 160A is used to treat the surface of the tool Bombardment cleaning for 50 minutes;

3) Under the protection of argon gas with a pressure of 1.5×10 ^-1 Pa, heat the Ti ingot with a hot cathode ion column arc with a current of 220A to evaporate it, and plate the tool for 5 minutes to form a layer of Ti sticky on the surface. Adhesive layer, and then feed a mixed gas of argon and nitrogen with a flow ratio of 1:2, and plate at a pressure of 4.5×10 ^-1 Pa for 25 minutes, so that a layer of TiN transition layer is formed on the surface of the Ti adhesive layer;

4) According to the flow ratio of 1:2.5, the mixed gas of argon and nitrogen is introduced into the coating chamber, and the pressure is kept at 4.5×10 ^-1 Pa, and the DC bias voltage of the tool is adjusted to -70V, and the arc current of the hot cathode ion column is adjusted. At the same time, turn on the control power supply of the intermediate frequency reactive magnetron sputtering to sputter the composite alloy target of Ti:Al=50:50, and keep the current of the TiAl target at 6.0A for 180min, so that the TiN transition layer of the tool A layer of TiAlN coating is formed on the surface, and then cooled naturally.

Comparative example 2

1) Put the cemented carbide milling cutter after degreasing, sandblasting and ultrasonic cleaning by conventional methods into the coating chamber, first vacuum the coating chamber to 5.0×10 ^-3 Pa, and then pass in argon gas to make the coating The total indoor pressure is 4.5×10 ^-1 Pa, the hot cathode ion column arc is turned on so that the current is 180A, and the tool is heated for 80min;

2) Under the protection of argon gas with a pressure of 2.0×10 ^-1 Pa, the DC bias voltage of the tool is controlled to -200V, the pulse bias voltage is -800V, and then the plasma generated by the hot cathode ion column arc with a current of 160A is used to treat the surface of the tool Bombardment cleaning for 50 minutes;

3) Under the protection of argon gas with a pressure of 1.5×10 ^-1 Pa, heat the Ti ingot with a hot cathode ion column arc with a current of 220A to evaporate it, and plate the tool for 5 minutes to form a Ti transition layer on the surface ;

4) According to the flow ratio of 1:2.5, the mixed gas of argon and nitrogen is introduced into the coating chamber, and the pressure is kept at 4.5×10 ^-1 Pa, and the DC bias voltage of the tool is adjusted to -70V, and the arc current of the hot cathode ion column is adjusted. At the same time, turn on the control power supply of the intermediate frequency reactive magnetron sputtering to sputter the composite alloy target of Ti:Al:Si=60:30:10, and keep the current of the TiAlSi target at 6.0A for 180min, so that the tool A layer of TiAlSiN coating is formed on the surface of the Ti transition layer, and then cooled naturally.

Comparative example 3

1) Put the cemented carbide milling cutter after degreasing, sandblasting and ultrasonic cleaning by conventional methods into the coating chamber, first vacuum the coating chamber to 5.0×10 ^-3 Pa, and then pass in argon gas to make the coating The total indoor pressure is 4.5×10 ^-1 Pa, the hot cathode ion column arc is turned on so that the current is 180A, and the tool is heated for 80min;

2) Under the protection of argon gas with a pressure of 2.0×10 ^-1 Pa, the DC bias voltage of the tool is controlled to -200V, the pulse bias voltage is -800V, and then the plasma generated by the hot cathode ion column arc with a current of 160A is used to treat the surface of the tool Bombardment cleaning for 50 minutes;

3) Under the protection of argon gas with a pressure of 1.5×10 ^-1 Pa, heat the Ti ingot with a hot cathode ion column arc with a current of 220A to evaporate it, and plate the tool for 5 minutes to form a layer of Ti adhesion on the surface layer, and then flow a mixed gas of argon and nitrogen with a flow ratio of 1:2, and plate at a pressure of 4.5×10 ^-1 Pa for 25 minutes, so that a layer of TiN transition layer is formed on the surface of the Ti adhesion layer;

4) According to the flow ratio of 1:2.5, the mixed gas of argon and nitrogen is introduced into the coating chamber, and the pressure is kept at 4.5×10 ^-1 Pa, and the DC bias voltage of the tool is adjusted to -70V, and the arc current of the hot cathode ion column is adjusted. At the same time, turn on the control power supply of the intermediate frequency reactive magnetron sputtering to sputter the composite alloy target of Ti:Al:Cr=20:70:10, and keep the current of the TiAlCr target at 6.0A for 180min, so that the tool A layer of TiAlCrN coating is formed on the surface of the TiN transition layer, and then cooled naturally.

In order to investigate gained composite coating of the present invention and comparative example tool composite coating performance, the present invention has done following detection to it:

1) Observation of coating fracture morphology

A scanning electron microscope (S300-N, Hitachi, Japan) was used to observe and test the fracture morphology of the coatings obtained in Example 4 of the present invention and Comparative Examples 1-3, and the results are shown in Figures 1, 2, 3, and 4, respectively. From Figure 1, it can be seen that the Cr/CrN/(Ti,Al,Si,Cr)N composite hard coating has a finer fracture structure than the Ti/TiN/TiAlN coating, and secondly, the Cr/CrN/(Ti,Al,Si, The fracture structure of Cr)N composite hard coating is divided into three layers, and the outermost layer (Ti, Al, Si, Cr)N coating structure is nanocrystalline; the fracture morphology of the coating in Figure 2 is a typical columnar crystal, This kind of crystal is easy to break when it is subjected to lateral load; the coating in Figure 3 has no obvious columnar shape, and there is an obvious interface between the coating and the substrate, so the bonding force is low; the coating in Figure 4 has no columnar crystal shape, which is consistent with There is no obvious interface between the matrix, and this form has low hardness and high toughness. Therefore, the Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating of the present invention has better mechanical properties than the present invention.

2) Coating nanohardness test

Using a nanohardness tester MTS Systems Corp., Oak Ridge, TN, USA, according to the surface approach speed of 10nm/s, the minimum indentation depth of 200nm, and the maximum indentation depth of 500nm, the coatings obtained in the embodiments of the present invention and comparative examples 1-3 were tested. Wherein the test results of the coating obtained in Example 4 of the present invention and Comparative Examples 1-3 are shown in the following table. From the test results in the table, the Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating obtained in Example 4 of the present invention has higher hardness than the Ti/TiN/TiAlN coating in Comparative Example 1 and lower modulus of elasticity; the Ti/TiAlSiN coating in comparative example 2 has higher hardness, but the modulus of elasticity is also higher; the Ti/TiN/TiAlCrN coating in comparative example 3 has lower hardness and lower modulus of elasticity lower.

surface

3) Coating and substrate bonding force test

Adopt Rockwell hardness tester HR-150A type, under the HRC diamond indenter of taper angle 120 °, under the load 60Kg, the coating and substrate binding force obtained in embodiment 4 of the present invention and comparative examples 1-3 are tested, and the results are shown in Fig. 5 , 6, 7, 8. From Figure 5, it can be observed that Cr/CrN/(Ti,Al,Si,Cr)N composite hard coating indentation does not appear large-scale shedding, only fine cracks exist, indicating that the coating has a high bonding force with the tool matrix, and the coating The level of bonding force between the layer and the tool substrate is HF1; from Figure 6, it can be observed that the indentation of the Ti/TiN/TiAlN coating has a large-scale shedding phenomenon, indicating that the bonding force between the coating and the tool substrate is low, and the level of bonding force between the coating and the tool substrate is It is HF4; from Figure 7, it can be observed that the indentation of the Ti/TiAlSiN coating also has a large-scale shedding phenomenon, indicating that the bonding force between the coating and the tool substrate is low, and the bonding force between the coating and the tool substrate is HF4; it can be observed from Figure 8 The indentation of Ti/TiN/TiAlCrN coating has no obvious peeling off, but the crack is more obvious than that of Cr/CrN/(Ti,Al,Si,Cr)N composite hard coating, and the bonding force between the coating and the tool matrix is HF2 .

4) XRD test of the coating

The Cr/CrN/(Ti,Al,Si,Cr)N composite hard coating prepared by the present invention was tested by XRD with DX-1000 XRD equipment (Cu target), and the results are shown in FIG. 5 . It can be seen from Figure 5 that the XRD pattern of the Cr/CrN/(Ti, Al, Si, Cr)N composite hard coating is that the TiN(111) plane diffraction intensity is <100, and the TiN(200) plane diffraction intensity is 300. This shows that the coating has high comprehensive mechanical properties.

Claims (8)

1. a preparation method of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating, the processing steps and conditions of the method are as follows: 1) After installing the tool into the coating chamber, first vacuum the coating chamber to at least 5.0×10 ^-3 Pa, and then pass in argon to make the total pressure in the coating chamber 3.0×10 ^-1 ~ 4.5×10 ^-1 Pa, Turn on the hot cathode ion column arc so that the current is 140-180A, and heat the tool for 40-150 minutes; 2) Under the protection of argon gas with a pressure of 1.5×10 ^-1 ~ 2.0×10 ^-1 Pa, control the tool DC bias voltage -100 ~ -200V, pulse bias voltage -500 ~ -800V, and then use a current of 110 ~ 160A The plasma generated by the hot cathode ion column arc bombards and cleans the tool surface for 15-50 minutes; 3) Under the protection of argon gas with a pressure of 8.0×10 ^-2 ~1.5×10 ^-1 Pa, heat the Cr ingot with a hot cathode ion column arc with a current of 180~220A to evaporate it, and plate the tool for 5~10min Form a layer of ^Cr adhesion layer on the surface, then ^pass nitrogen gas, and plate 15 ~30min to form a CrN transition layer on the surface of the Cr adhesion layer; 4) Continue to feed the mixed gas of argon and nitrogen into the coating chamber according to the flow ratio of 1:1.5~3, so that the pressure is 3.0×10 ^-1 ~4.5×10 ^-1 Pa, and adjust the DC bias voltage of the tool to - 40～-70V, the hot cathode ion column arc current is adjusted to 100～110A, and at the same time turn on the control power supply of the intermediate frequency reaction magnetron sputtering, and keep the current of the TiAlSiCr target at 4.0～7.0A for 120～180min, so that the tool A layer of (Ti, Al, Si, Cr)N coating is formed on the surface of the CrN transition layer, and then cooled naturally. 2. the preparation method of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating according to claim 1, the TiAlSiCr target used in the method step 4) is Ti _X Al _Y Si _Z The Cr _(1-XYZ) composite alloy target has a titanium aluminum silicon chromium atomic ratio of 50-70:20-30:1-7:1-5 and a purity of 99.99%. 3. the preparation method of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating according to claim 1, the pressure of plating Cr adhesion layer in the 3rd) step of this method is 8.0× 10 ^-2 ~ 1.2×10 ^-1 Pa, the current of the hot cathode ion column arc is 200 ~ 220A, and the plating time is 5 ~ 7min. 4. the preparation method of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coat according to claim 1, the argon gas and the nitrogen gas of plating CrN transition layer in the method 3) step The flow ratio is 1:1.5~2.5, the pressure is 4.0×10 ^-1 ~4.5×10 ^-1 Pa, and the plating time is 15~25min. 5. according to the preparation method of the Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating described in claim 1 or 2 or 3 or 4, in the 4th) step of the method, plating system (Ti, The flow ratio of argon and nitrogen for Al, Si, Cr)N coating is 1:1.5~2.5, the hot cathode ion column arc current is 105~110A, the current of TiAlSiCr target is kept at 5.0~7.0A, and the plating time is 120 ~160min. 6. according to the preparation method of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating according to claim 2, the titanium-aluminum-silicon-chromium atomic ratio in the used TiAlSiCr target of this method step 4) is 65～70: 20～28: 1～6: 1～4. 7. the preparation method of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating according to claim 5, the titanium-aluminum-silicon-chromium atomic ratio in the used TiAlSiCr target of the method 4) step is 65～70: 20～28: 1～6: 1～4. 8. a kind of Cr/CrN/(Ti, Al, Si, Cr) N composite hard coating prepared by the method described in claim 1, this composite hard coating is three layers, outwards from cutter surface successively is Cr adhesion layer, CrN transition layer and (Ti, Al, Si, Cr) N coating, its nanohardness ≥ 34Gpa, and the level of bonding force with the tool substrate reaches HF1-HF2 of German standard VDI3198, in which the thickness of Cr adhesion layer The thickness of the CrN transition layer is 100-500nm, the thickness of the (Ti,Al,Si,Cr)N coating is 2-5μm, and the structure of the (Ti,Al,Si,Cr)N coating is Nanocrystalline structure, the diffraction intensity of TiN(111) plane in X-ray diffraction is <100, and the diffraction intensity of TiN(200) plane is ≥300.