Cr / crn / wc / c nano-coating and its preparation method and application

Abstract

The application belongs to the technical field of finishing, and provides a Cr / CrN / WC / C nano coating, a preparation method and application thereof, and the nano coating is a high-strength and high-toughness hydrogen-free carbon-based nano coating. The binding force layer is a metal Cr layer, temperature-resistant Cr is selected as the binding force layer, the thickness is controlled to be 200-500 nm, under the premise of guaranteeing excellent binding performance, the design of wide temperature range binding strength is realized. CrN is used as a gradient transition layer, the thickness is controlled to be 300-500 nm, high-power magnetron sputtering ion enhanced composite deposition technology can be used to continuously grow dense CrN on the Cr binding force layer, the mechanical performance is kept to be gradually increased, the structure can be kept to be continuously and densely grown, and the oxidation resistance is better than that of the Cr layer. The WC layer is a high-strength and high-toughness layer of the coating, the thickness is controlled to be 600-1500 nm, and the strength and toughness of the whole coating can be improved; and the C layer plays a mechanical lubrication role.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of finishing technology, in particular to a Cr / CrN / WC / C nano coating and a preparation method and application thereof. BACKGROUND

[0002] Boring cutter is a kind of boring cutter, generally round handle, the most common occasion is hole processing, reaming, profiling, etc. One or two cutting parts are special tools for rough machining, semi-finishing or finishing of existing holes. Small hole boring cutter is an indispensable tool in finishing, and the small hole boring cutter tip is sharp, which is easy to crack in the use process, thereby affecting the workpiece and increasing the processing cost. In order to solve such problems, two methods are mainly used. One is to study higher strength alloy, but the development is difficult, the technical requirement is high, and the cycle is long. The other is to prepare coating on the surface of small hole boring cutter to improve the strength of the cutter tip. Although the coating preparation technology has low technical requirements, the coating prepared by the current coating preparation technology still has the defects of insufficient strength and toughness, poor adhesion between the coating and the substrate, and uneven coating, which cannot meet the machining requirements. Therefore, it is an urgent problem to provide a new coating for small hole boring cutter. SUMMARY

[0003] The present application aims to overcome the defects in the prior art and provide a Cr / CrN / WC / C nano coating, a preparation method and application thereof.

[0004] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0005] The present application provides a Cr / CrN / WC / C nano coating, which comprises, from bottom to top, a Cr metal adhesion layer, a CrN nano composite coating, a WC nano coating and a C coating.

[0006] The thickness of the Cr metal adhesion layer is 200-500 nm, the thickness of the CrN nano composite coating is 300-500 nm, and the thickness of the WC nano coating is 600-1500 nm.

[0007] The present application also provides a preparation method of the Cr / CrN / WC / C nano coating, which comprises the following steps:

[0008] (1) using Cr target to activate and pulse magnetron sputter the substrate to form a Cr metal adhesion layer;

[0009] (2) using Cr target to pulse magnetron sputter on the surface of the Cr metal adhesion layer to form a CrN nano composite coating;

[0010] (3) using WC target and C target to perform pulse magnetron sputtering on the surface of the CrN nanocomposite coating to form a WC nanocoating;

[0011] (4) using C target to perform pulse magnetron sputtering on the surface of the WC nanocoating to form a C coating, thus obtaining the Cr / CrN / WC / C nanocoating.

[0012] Preferably, the micro-pulse parameters in the activation of step (1) are 2-40 μs, the average power is 2-10 kW, the gas pressure is 0.3-2 Pa, the argon flow rate is 100-130 sccm, and the bias voltage is -30 to -200 V.

[0013] Preferably, the bias voltage in the pulse magnetron sputtering of step (1) is -60 to -100 V.

[0014] Preferably, the micro-pulse parameters in the pulse magnetron sputtering of step (2) are 2-40 μs, the average power is 2-10 kW, the gas pressure is 0.8-2 Pa, the argon flow rate is 100-130 sccm, the nitrogen flow rate is 30-120 sccm, and the bias voltage is -60 to -150 V.

[0015] Preferably, the micro-pulse parameters in the pulse magnetron sputtering of step (3) using WC target are 6-30 μs, the average power is 6-10 kW, the gas pressure is 0.6-2 Pa, the argon flow rate is 100-130 sccm, the nitrogen flow rate is 100-130 sccm, and the bias voltage is -60 to -300 V.

[0016] Preferably, the pulse direct current power parameters in the pulse magnetron sputtering of step (3) using C target are 80-120 kHz, the average power is 0.4-8 kW.

[0017] Preferably, the gas pressure in the pulse magnetron sputtering of step (3) is 0.6-2 Pa, the argon flow rate is 100-130 sccm, the nitrogen flow rate is 100-130 sccm, and the bias voltage is -60 to -300 V.

[0018] Preferably, the micro-pulse parameters in the pulse magnetron sputtering of step (4) are 2-40 μs, the average power is 2-10 kW, the gas pressure is 0.8-2 Pa, the argon flow rate is 100-130 sccm, the bias voltage is -60 to -150 V, and the time is 30-60 min.

[0019] The application also provides the use of the Cr / CrN / WC / C nanocoating in a small-hole boring tool.

[0020] The application provides a Cr / CrN / WC / C nano coating, which is a high-strength and high-toughness hydrogen-free carbon-based nano coating.

[0021] The application selects CrN as a gradient transition layer, and the thickness is controlled to be 300-500nm; the high-power magnetron sputtering ion enhanced composite deposition technology can be used to continuously grow the dense CrN on the Cr binding force layer, and the mechanical properties are kept to be gradiently increased; the structure can be kept to be continuously and densely grown, and the oxidation resistance is better than that of the Cr layer.

[0022] The WC layer is a high-strength and high-toughness layer of the coating, and the thickness is controlled to be 600-1500nm, so that the strength and toughness of the whole coating can be improved. 3 2 IC 1 / 2

[0023] The application selects the C layer as a lubricating layer, so that the mechanical lubrication of the high-strength and high-toughness nano coating is provided, and the friction coefficient in the mechanical cutting process is further reduced to be less than or equal to 0.1.

[0024] The application also provides a preparation method of the Cr / CrN / WC / C nano coating.

[0025] The Cr / CrN / WC / C nano coating provided by the application is applied to small-hole and deep-hole boring cutter cutting, and the cutting performance and service life can be significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a physical picture of the Cr / CrN / WC / C nano coating in Example 1.

[0027] Figure 2 ​​​​Figure for indentation test of the Cr / CrN / WC / C nano-coating in Example 1. DETAILED DESCRIPTION

[0028] The present application provides a Cr / CrN / WC / C nano-coating, from bottom to top, Cr metal adhesion layer, CrN nano-composite coating, WC nano-coating and C coating.

[0029] In the present application, the thickness of the Cr metal adhesion layer is 200-500 nm, preferably 240-460 nm, further preferably 280-420 nm, and more preferably 330-370 nm.

[0030] In the present application, the thickness of the CrN nano-composite coating is 300-500 nm, preferably 330-470 nm, further preferably 360-440 nm, and more preferably 380-420 nm.

[0031] In the present application, the thickness of the WC nano-coating is 600-1500 nm, preferably 700-1400 nm, further preferably 800-1300 nm, and more preferably 900-1200 nm.

[0032] The present application also provides a preparation method of the Cr / CrN / WC / C nano-coating, comprising the following steps:

[0033] (1) using Cr target to activate and pulse magnetron sputter the substrate to form Cr metal adhesion layer;

[0034] (2) using Cr target to pulse magnetron sputter on the surface of the Cr metal adhesion layer to form CrN nano-composite coating;

[0035] (3) using WC target and C target to pulse magnetron sputter on the surface of the CrN nano-composite coating to form WC nano-coating;

[0036] (4) using C target to pulse magnetron sputter on the surface of the WC nano-coating to form C coating, thus obtaining the Cr / CrN / WC / C nano-coating.

[0037] In the present application, the substrate is cleaned before use in step (1), the cleaning medium is ethanol or acetone, and the ultrasonic cleaning time is preferably 15-20 min, further preferably 16-19 min, and more preferably 17-18 min.

[0038] In the present application, the cleaned substrate is placed in a vacuum chamber, and the vacuum degree is preferably ≤1*10 -3 Pa, further preferably ≤0.8*10 -3 Pa, and more preferably ≤0.5*10 -3Pa.

[0039] In the present application, the substrate is ion cleaned after the vacuum reaches the requirement, the pulsed direct current is connected to the substrate, the bias voltage of the ion cleaning is preferably -500-600V, further preferably -300-400V, more preferably -100-200V; the pulsed direct current power parameter is preferably 80-120KHz, further preferably 85-115KHz, more preferably 90-110KHz; the pulsed direct current power parameter is preferably 1-5μs, further preferably 2-4μs, more preferably 3μs; the gas pressure is preferably 0.3-2Pa, further preferably 0.5-1.5Pa, more preferably 0.8-1.2Pa; the argon flow is preferably 100-130sccm, further preferably 105-125sccm, more preferably 110-120sccm; the time is preferably 30-60min, further preferably 35-55min, more preferably 40-50min.

[0040] In the present application, the micro-pulse parameter of the activation in step (1) is preferably 2-40μs, further preferably 10-30μs, more preferably 15-25μs; the average power is preferably 2-10kW, further preferably 3-9kW, more preferably 4-8kW; the gas pressure is preferably 0.3-2Pa, further preferably 0.5-1.5Pa, more preferably 0.8-1.2Pa; the argon flow is preferably 100-130sccm, further preferably 105-125sccm, more preferably 110-120sccm; the bias voltage is preferably -30--200V, further preferably -50--180V, more preferably -80--150V; the time is preferably 1-5min, further preferably 2-4min, more preferably 2.5-3.5min.

[0041] In the present application, the purpose of the activation in step (1) is to activate the substrate surface by ion bombardment, improve the ion surface migration ability, and promote nucleation.

[0042] In the present application, the bias voltage of the pulsed magnetron sputtering in step (1) is preferably -60--100V, further preferably -70--90V, more preferably -75--80V.

[0043] In the present application, the micro-pulse parameters of the pulsed magnetron sputtering in step (2) are preferably 2-40 μs, further preferably 5-30 μs, and more preferably 10-20 μs; the average power is preferably 2-10 kW, further preferably 3-9 kW, and more preferably 4-8 kW; the gas pressure is preferably 0.8-2 Pa, further preferably 1-1.8 Pa, and more preferably 1.3-1.5 Pa; the argon flow rate is preferably 100-130 sccm, further preferably 105-125 sccm, and more preferably 110-120 sccm; the nitrogen flow rate is preferably 30-120 sccm, further preferably 40-100 sccm, and more preferably 60-80 sccm; and the bias voltage is preferably -60 to -150 V, further preferably -80 to -140 V, and more preferably -100 to -120 V.

[0044] In the present application, the WC target is connected to a high-power pulse power source or a deep oscillation power source to ensure sufficient ionization rate in step (3), and the micro-pulse parameters of the pulsed magnetron sputtering using the WC target are preferably 6-30 μs, further preferably 10-25 μs, and more preferably 15-20 μs; and the average power is preferably 6-10 kW, further preferably 7-9 kW, and more preferably 7.5-8 kW.

[0045] In the present application, the C target is connected to a pulsed direct current power source in step (3), and the pulsed direct current power source parameters of the pulsed magnetron sputtering using the C target are preferably 80-120 kHz, further preferably 85-115 kHz, and more preferably 90-110 kHz; and the average power is preferably 0.4-8 kW, further preferably 2-6 kW, and more preferably 3-5 kW.

[0046] In the present application, the gas pressure of the pulsed magnetron sputtering in step (3) is preferably 0.6-2 Pa, further preferably 1-1.5 Pa, and more preferably 1.2-1.3 Pa; the argon flow rate is preferably 100-130 sccm, further preferably 105-125 sccm, and more preferably 110-120 sccm; the nitrogen flow rate is preferably 100-130 sccm, further preferably 105-125 sccm, and more preferably 110-120 sccm; and the bias voltage is preferably -60 to -300 V, further preferably -80 to -250 V, and more preferably -100 to -200 V.

[0047] In the present application, after the graphite target (C) is ionized, a plasma chemical reaction occurs with the ionized WC target, and the WC coating is recombined. After the C (SP3) is ionized, the combination with W ions is promoted, and part of the C exists in the form of graphite (SP2).

[0048] In the present application, the micro-pulse parameters of the pulsed magnetron sputtering in step (4) are preferably 2-40 μs, further preferably 10-30 μs, and more preferably 15-25 μs; the average power is preferably 2-10 kW, further preferably 4-8 kW, and more preferably 5-6 kW; the gas pressure is preferably 0.8-2 Pa, further preferably 1-1.8 Pa, and more preferably 1.2-1.5 Pa; the argon flow rate is preferably 100-130 sccm, further preferably 105-125 sccm, and more preferably 110-120 sccm; the bias voltage is preferably -60 to -150 V, further preferably -80 to -140 V, and more preferably -100 to -120 V; and the time is preferably 30-60 min, further preferably 35-55 min, and more preferably 40-50 min.

[0049] In the present application, the Cr / CrN / WC / C nanocoating is obtained after the pulsed magnetron sputtering in step (4) is completed, and the standing time is preferably 30-60 min, further preferably 35-55 min, and more preferably 40-50 min.

[0050] The present application also provides the application of the Cr / CrN / WC / C nanocoating in a small-hole boring tool.

[0051] The technical solutions provided by the present application will be described in detail below in conjunction with the examples, but they should not be understood as limiting the scope of protection of the present application.

[0052] Example 1

[0053] The substrate is cleaned in ethanol for 15 min under ultrasonic waves, and then dried by compressed air after being taken out; the substrate is placed on a sample platform in a vacuum chamber, and the vacuum degree is controlled to be 0.8*10 -3 Pa; the pulsed direct current power supply is connected to the substrate, the bias voltage is set to be 200 V, 100 KHz, 1 μs, the gas pressure is 1 Pa, the argon flow rate is 120 sccm, and the ion cleaning is completed after cleaning for 40 min.

[0054] The Cr target is connected, the high-power pulsed magnetron sputtering is started, the micro-pulse parameters are set to be 25 μs, the average power is set to be 8 kW, the gas pressure is set to be 1 Pa, the argon flow rate is set to be 120 sccm, and the bias voltage is set to be -80 V, and the Cr metal adhesion layer with a thickness of 300 nm is prepared after activation for 3 min.

[0055] The high-power pulsed magnetron sputtering is started, the micro-pulse parameters are set to be 30 μs, the average power is set to be 5 kW, the gas pressure is set to be 1 Pa, the argon flow rate is set to be 110 sccm, the nitrogen flow rate is set to be 40 sccm, and the bias voltage is set to be -110 V, and the CrN nanocomposite coating with a thickness of 400 nm is prepared.

[0056] The WC target is connected to the high-power pulse power supply, and the C target is connected to the pulse direct current power supply. The micro pulse parameters of the pulse magnetron sputtering of the WC target are 25 μs, and the average power is 10 kW. The pulse direct current power supply parameters of the pulse magnetron sputtering of the C target are 100 kHz and 6 kW. The gas pressure is 1.5 Pa, the argon flow rate is 120 sccm, the nitrogen flow rate is 120 sccm, and the bias voltage is -240 V. A 1000 nm WC nanocoating is prepared.

[0057] The C target is connected to the high-power pulse power supply. The micro pulse parameters are set to 23 μs, the average power is 8 kW, the gas pressure is 2 Pa, the argon flow rate is 110 sccm, and the bias voltage is -90 V. A C coating is prepared for 40 min.

[0058] After the coating preparation is completed, the Cr / CrN / WC / C nanocoating is obtained after standing for 40 min.

[0059] The Cr / CrN / WC / C nanocoating prepared in this example is shown in FIG. 1. Figure 1 The left side of the figure is a coated boring cutter, and the right side is a boring cutter without coating.

[0060] The Cr / CrN / WC / C nanocoating prepared in this example is subjected to indentation testing, and the results are shown in FIG. 2. Figure 2 As can be seen from the figure, no radiation cracks are generated after the indentation testing, indicating that the fracture toughness is high.

[0061] Example 2

[0062] The substrate is ultrasonically cleaned in ethanol for 20 min, and then dried with compressed air after being taken out. The substrate is placed on the sample platform in the vacuum chamber, and the vacuum degree is controlled to be 1*10 -3 Pa. The pulse direct current power supply is connected to the substrate, and the bias voltage is set to -300 V, 90 kHz, 3 μs. The gas pressure is 2 Pa, the argon flow rate is 110 sccm, and the ion cleaning is performed for 30 min.

[0063] The Cr target is connected, and the high-power pulse magnetron sputtering is enabled. The micro pulse parameters are set to 30 μs, the average power is 4 kW, the gas pressure is 2 Pa, the argon flow rate is 110 sccm, and the bias voltage is -90 V. The Cr metal adhesion layer with a thickness of 400 nm is prepared after being activated for 5 min.

[0064] The high-power pulse magnetron sputtering is enabled. The micro pulse parameters are set to 10 μs, the average power is 6 kW, the gas pressure is 1.5 Pa, the argon flow rate is 100 sccm, the nitrogen flow rate is 40 sccm, and the bias voltage is -120 V. The CrN nanocomposite coating with a thickness of 300 nm is prepared.

[0065] The WC target is connected to the high-power pulse power supply, and the C target is connected to the pulse direct current power supply. The micro pulse parameters of the pulse magnetron sputtering of the WC target are 15 μs, and the average power is 10 kW. The pulse direct current power supply parameters of the pulse magnetron sputtering of the C target are 90 kHz, 5 kW, the gas pressure is 2 Pa, the argon flow rate is 110 sccm, the nitrogen flow rate is 120 sccm, and the bias voltage is -200 V. The WC nanocoating with a thickness of 700 nm is prepared.

[0066] The C target is connected to the high-power pulse power supply, the micro pulse parameters are set to 20 μs, the average power is 6 kW, the gas pressure is 1 Pa, the argon flow rate is 120 sccm, the bias voltage is -140 V, and the time is 60 min. The C coating is prepared.

[0067] After the coating preparation is completed, the Cr / CrN / WC / C nanocoating is obtained after standing for 50 min.

[0068] Example 3

[0069] The substrate is placed in acetone and ultrasonically cleaned for 20 min, and then taken out and dried with compressed air. The substrate is placed on a sample platform in a vacuum chamber, and the vacuum degree is controlled to be 1*10 -3 Pa. The pulse direct current power supply is connected to the substrate, the bias voltage is set to -600 V, 110 KHz, 3 μs, the gas pressure is 2 Pa, the argon flow rate is 100 sccm, and the ion cleaning is performed for 40 min.

[0070] The Cr target is connected, the high-power pulse magnetron sputtering is started, the micro pulse parameters are set to 10 μs, the average power is 5 kW, the gas pressure is 1.8 Pa, the argon flow rate is 115 sccm, the bias voltage is -100 V, and the activation is performed for 3 min. Then the bias voltage is changed to -70 V, and the Cr metal adhesion layer with a thickness of 350 nm is prepared.

[0071] The high-power pulse magnetron sputtering is started, the micro pulse parameters are set to 30 μs, the average power is 3 kW, the gas pressure is 1.5 Pa, the argon flow rate is 100 sccm, the nitrogen flow rate is 60 sccm, and the bias voltage is -110 V. The CrN nanocomposite coating with a thickness of 420 nm is prepared.

[0072] The WC target is connected to the high-power pulse power supply, and the C target is connected to the pulse direct current power supply. The micro pulse parameters of the pulse magnetron sputtering of the WC target are 17 μs, and the average power is 7 kW. The pulse direct current power supply parameters of the pulse magnetron sputtering of the C target are 95 kHz, 6 kW, the gas pressure is 2 Pa, the argon flow rate is 120 sccm, the nitrogen flow rate is 100 sccm, and the bias voltage is -180 V. The WC nanocoating with a thickness of 1200 nm is prepared.

[0073] The C target was connected to the high-power pulse power supply, and the micro pulse parameters were set as 35 μs, the average power was 5 kW, the gas pressure was 1 Pa, the argon flow rate was 105 sccm, the bias voltage was-90 V, and the time was 45 min to prepare the C coating.

[0074] After the coating preparation was completed, the Cr / CrN / WC / C nanocoating was obtained after standing for 40 min.

[0075] Example 4

[0076] The substrate was ultrasonically cleaned in acetone for 15 min, and then dried with compressed air after being taken out; the substrate was placed on the sample platform in the vacuum chamber, and the vacuum degree was controlled to be 0.6*10 -3 Pa; the pulse direct current power supply was connected to the substrate, and the bias voltage was set to 300 V, 95 KHz, 3 μs, the gas pressure was 1.8 Pa, the argon flow rate was 110 sccm, and the ion cleaning was performed for 50 min.

[0077] The Cr target was connected, and the high-power pulse magnetron sputtering was started, the micro pulse parameters were set as 15 μs, the average power was 8 kW, the gas pressure was 2 Pa, the argon flow rate was 105 sccm, the bias voltage was-70 V, and the activation was performed for 5 min; then the bias voltage was changed to-60 V, and the Cr metal adhesion layer with a thickness of 260 nm was prepared.

[0078] The high-power pulse magnetron sputtering was started, the micro pulse parameters were set as 25 μs, the average power was 7 kW, the gas pressure was 1.1 Pa, the argon flow rate was 120 sccm, the nitrogen flow rate was 40 sccm, and the bias voltage was-100 V, and the CrN nanocomposite coating with a thickness of 340 nm was prepared.

[0079] The WC target was connected to the high-power pulse power supply, and the C target was connected to the pulse direct current power supply, the micro pulse parameters of the pulse magnetron sputtering of the WC target were 28 μs, and the average power was 9 kW; the pulse direct current power supply parameters of the pulse magnetron sputtering of the C target were 108 kHz, 7 kW, the gas pressure was 2 Pa, the argon flow rate was 115 sccm, the nitrogen flow rate was 120 sccm, and the bias voltage was-90 V, and the WC nanocoating with a thickness of 720 nm was prepared.

[0080] The C target was connected to the high-power pulse power supply, the micro pulse parameters were set as 30 μs, the average power was 7 kW, the gas pressure was 1 Pa, the argon flow rate was 120 sccm, the bias voltage was-120 V, and the time was 50 min to prepare the C coating.

[0081] After the coating preparation was completed, the Cr / CrN / WC / C nanocoating was obtained after standing for 60 min.

[0082] The Cr / CrN / WC / C nanocoatings prepared in Examples 1-4 were tested for performance, and the results are recorded in Table 1.

[0083] Table 1 Performance test results

[0084] Sample Bonding force Hardness (GPa) Fracture toughness (MPa-m 1 / 2 ) Elastic recovery (%) Example 1 ≥ HF1 38.9 4.7 67.2 Example 2 ≥ HF1 41.5 3.4 64.8 Example 3 ≥ HF1 42.3 3.3 63.1 Example 4 ≥ HF1 41.8 3.5 65.4

[0085] From the above examples, the application provides a Cr / CrN / WC / C nano coating, which has excellent film base bonding force, elastic recovery, hardness and fracture toughness, is suitable for small hole, deep space boring cutter cutting processing, and significantly improves the cutting performance and service life.

[0086] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method for producing a Cr / CrN / WC / C nanocoating, characterized in that, It comprises the following steps: (1) using Cr target to activate and pulse magnetron sputtering on the substrate to form Cr metal adhesion layer; (2) using Cr target to pulse magnetron sputtering on the surface of Cr metal adhesion layer to form CrN nanocomposite coating; (3) using WC target and C target to pulse magnetron sputtering on the surface of CrN nanocomposite coating to form WC nanocoating; (4) using C target to pulse magnetron sputtering on the surface of WC nanocoating to form C coating, namely the Cr / CrN / WC / C nanocoating is obtained; The micro pulse parameters of the pulse magnetron sputtering in step (2) are 2-40 μs, the average power is 2-10 kW, the gas pressure is 0.8-2 Pa, the argon flow rate is 100-130 sccm, the nitrogen flow rate is 30-120 sccm, and the bias voltage is-60--150 V; The micro pulse parameters of the pulse magnetron sputtering using WC target in step (3) are 6-30 μs, and the average power is 6-10 kW; The pulse direct current power parameters of the pulse magnetron sputtering using C target in step (3) are 80-120 kHz, and the average power is 0.4-8 kW; The gas pressure of the pulse magnetron sputtering in step (3) is 0.6-2 Pa, the argon flow rate is 100-130 sccm, the nitrogen flow rate is 100-130 sccm, and the bias voltage is-60--300 V; The micro pulse parameters of the pulse magnetron sputtering in step (4) are 2-40 μs, the average power is 2-10 kW, the gas pressure is 0.8-2 Pa, the argon flow rate is 100-130 sccm, the bias voltage is-60--150 V, and the time is 30-60 min.

2. The method for preparing a Cr / CrN / WC / C nanocoating according to claim 1, characterized in that, The micro pulse parameters of the activation in step (1) are 2-40 μs, the average power is 2-10 kW, the gas pressure is 0.3-2 Pa, the argon flow rate is 100-130 sccm, and the bias voltage is-30--200 V.

3. The method for producing a Cr / CrN / WC / C nanocoating according to claim 2, characterized in that, The bias voltage of the pulse magnetron sputtering in step (1) is-60--100 V.

4. The Cr / CrN / WC / C nanocoating prepared by the method of any one of claims 1-3, characterized in that, The thickness of the Cr metal adhesion layer is 200-500 nm, the thickness of the CrN nanocomposite coating is 300-500 nm, and the thickness of the WC nanocoating is 600-1500 nm.

5. The application of the Cr / CrN / WC / C nanocoating in a small hole boring tool according to claim 4.

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