A glc coating and a method for producing the same

Abstract

The application discloses a GLC coating and a preparation method thereof, relates to the technical field of solid material surface treatment, and the preparation method comprises the following steps: placing a pretreated base into a coating equipment to perform plasma cleaning; sequentially depositing a Cr base layer, a transition layer and a GLC layer doped with Cr on the surface of the cleaned base; the transition layer comprises a plurality of CrC layers which are sequentially deposited, each CrC layer is deposited by adopting a co-sputtering mode of a graphite target and a Cr target, the power of the graphite target is gradually increased, the power of the Cr target is gradually reduced, and the initial power of the Cr target is gradually reduced when the plurality of CrC layers are sequentially deposited. The application increases the SP3 component in the coating to a certain extent, the initial power of the Cr target is gradually reduced, the Cr content in the plurality of CrC layers is gradually reduced, the hardness of the plurality of CrC layers is gradually increased, the hardness transition is relatively gentle, the internal stress of the coating is small, and the adhesion of the coating is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solid material surface treatment, in particular to a GLC coating and a preparation method thereof. BACKGROUND

[0002] The gear of high-speed heavy-duty gearbox bears a large load and has a high rotating speed. At present, most high-speed heavy-duty gears adopt carburizing heat treatment to improve the surface hardness of the gear. The carburizing technical requirement is that the layer depth is 0.8-1.3 mm and the surface hardness of the gear is 58-63 HRC. However, as the horsepower of the engine is continuously improved, the torque of the gearbox matched with the engine is also continuously increased, so the load of the gear of the gearbox is also continuously increased, the friction of the surface of the gear is increased, and the failure of the gear is gradually aggravated, mostly pitting and peeling. In addition, as the double-carbon strategy is implemented, energy-saving and emission-reducing technology has become a technology that is vigorously developed in the automobile field, and reducing the friction coefficient of the gear can effectively improve the transmission efficiency of the gearbox.

[0003] In the related art, the surface of the gear can be treated by depositing a DLC (Diamond-like carbon) coating on the surface of the gear through induction quenching, so as to reduce the noise of the gearbox. However, the hardness of such a DLC coating is high, which causes the coating to be brittle, and the bonding force of the coating is poor, so there is still a risk of peeling of the coating. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide a GLC coating and a preparation method thereof, so as to solve the problem of poor bonding force of the coating in the related art and the risk of peeling.

[0005] The first aspect of the present application provides a preparation method of a GLC coating, which comprises the following steps:

[0006] The pretreated substrate is placed in a coating device for plasma cleaning;

[0007] A Cr primer layer, a transition layer, and a GLC layer doped with Cr are sequentially deposited on the surface of the cleaned substrate;

[0008] The transition layer comprises a plurality of CrC layers deposited in sequence, each CrC layer is deposited by co-sputtering of a graphite target and a Cr target, and the power of the graphite target is gradually increased and the power of the Cr target is gradually reduced; and

[0009] When the plurality of CrC layers are sequentially deposited, the initial power of the Cr target is sequentially reduced.

[0010] In some embodiments, the conditions for depositing the Cr primer layer on the surface of the cleaned substrate comprise:

[0011] The argon flow into the coating device is controlled at 25-35 sccm, the initial power of the Cr target is adjusted to 0.1 kW, and the initial bias voltage of the substrate is 120 V;

[0012] The power of the Cr target is kept unchanged after reaching the terminal power of 2.1-2.3 kW in the preset power increasing time, and the bias voltage of the substrate is kept unchanged after reaching the terminal bias voltage of 60 V in the preset bias voltage decreasing time, and the frequency of the bias voltage power source is 200-250 kHz; the preset power increasing time is the same as the preset bias voltage decreasing time;

[0013] The deposition time of the Cr undercoat layer is 1100-1600 s.

[0014] In some embodiments, the plurality of CrC layers are a first CrC layer, a second CrC layer and a third CrC layer, and the deposition time of each CrC layer is the same.

[0015] In some embodiments, the conditions for depositing the first CrC layer include:

[0016] The argon flow into the coating device is controlled at 25-35 sccm, the initial power of the graphite target is adjusted to 0.1 kW, and the terminal power is 3.4-3.8 kW; the initial power of the Cr target is adjusted to 2.1-2.3 kW, and the terminal power is 0.07-0.1 kW; the bias voltage of the substrate is 40 V, and the frequency of the bias voltage power source is 40-60 kHz; the deposition time of the first CrC layer, the power increasing time of the graphite target, and the power decreasing time of the Cr target are all 2000-5000 s.

[0017] In some embodiments, the conditions for depositing the second CrC layer include:

[0018] The argon flow into the coating device is controlled at 25-35 sccm, the initial power of the graphite target is adjusted to 0.1 kW, and the terminal power is 3.4-3.8 kW; the initial power of the Cr target is adjusted to 1.5-1.9 kW, and the terminal power is 0.07-0.1 kW; the bias voltage of the substrate is 60 V, and the frequency of the bias voltage power source is 40-60 kHz; the deposition time of the second CrC layer, the power increasing time of the graphite target, and the power decreasing time of the Cr target are all 2000-5000 s.

[0019] In some embodiments, the conditions for depositing the third CrC layer include:

[0020] The argon flow into the coating equipment is controlled at 25-35sccm, the initial power of the graphite target is adjusted to 0.1kW, and the terminal power is adjusted to 3.4-3.8kW; the initial power of the Cr target is adjusted to 1.0-1.4kW, and the terminal power is adjusted to 0.07-0.1kW; the substrate bias is 80V, and the frequency of the bias power supply is 40-60kHz; the deposition time of the third CrC layer, the power-up time of the graphite target, and the power-down time of the Cr target are all 2000-5000s.

[0021] In some embodiments, the conditions for depositing the GLC layer doped with Cr include:

[0022] The argon flow into the coating equipment is controlled at 15-20sccm, the power of the graphite target is adjusted to 3.4-3.8kW, the power of the Cr target is adjusted to 0.07-1.0kW, the initial bias of the substrate is adjusted to 40V, and the terminal bias is adjusted to 100V; the frequency of the bias power supply is 40-60kHz.

[0023] The deposition time of the GLC layer and the power-up time of the substrate are the same, both being 9-15h.

[0024] In some embodiments, the pretreated substrate is placed into the coating equipment for plasma cleaning, which specifically includes:

[0025] The substrate is placed into the unbalanced magnetron coating furnace, vacuumed to 3×10 -5 Pa, and argon is introduced at a flow rate of 1-2sccm.

[0026] The power of the graphite target is set to 0.1-0.15kW, the power of the Cr target is set to 0.1-0.15kW, and the bias parameters of the substrate are set as follows: the initial bias is 120V, the terminal bias is 500-600V, the power-up time is 60s, and the terminal bias is kept unchanged after reaching the terminal bias.

[0027] The linear ion source is turned on, and the linear ion source power parameters are set as follows: the initial voltage is 2000V, the terminal voltage is 2800-3000V, the power-up time is 60s, and the terminal voltage is kept unchanged after reaching the terminal voltage; the argon flow rate of the linear ion source is set to 20sccm.

[0028] The substrate rotation speed is set to 4RPM, and the plasma cleaning time is 15-20min.

[0029] In some embodiments, the substrate is a high-speed heavy-duty gear; the method further includes pretreating the high-speed heavy-duty gear, which specifically includes:

[0030] The high-speed heavy-duty gear is subjected to carburizing treatment, and the carburizing layer depth is 0.8-1.1mm.

[0031] The high-speed heavy load gear after the carburizing treatment is subjected to the gear grinding treatment, and the roughness after the gear grinding treatment is controlled to be Ra 0.2-0.4 μm.

[0032] The surface of the high-speed heavy load gear after the gear grinding treatment is subjected to the abrasive flow treatment, and the surface roughness is controlled to be Ra 0.07-0.1 μm.

[0033] The oil stains on the surface of the high-speed heavy load gear are removed by the ultrasonic cleaning, and the high-speed heavy load gear is dried.

[0034] The second aspect of the application provides a GLC coating, characterized in that the GLC coating is prepared by the preparation method.

[0035] The beneficial effects brought by the technical scheme provided in the application include:

[0036] The GLC coating and the preparation method thereof are characterized in that: the pretreated substrate is first placed into a coating device for plasma cleaning; then a Cr primer layer, a transition layer and a GLC layer doped with Cr are sequentially deposited on the surface of the cleaned substrate; since the transition layer comprises a plurality of CrC layers sequentially deposited, each CrC layer is deposited by using a graphite target and a Cr target for co-sputtering, and the power of the graphite target is gradually increased, and the power of the Cr target is gradually reduced; meanwhile, when the plurality of CrC layers are sequentially deposited, the initial power of the Cr target is sequentially reduced. Therefore, with the gradual increase of the power of the graphite target and the gradual reduction of the power of the Cr target, the content of SP3 in the coating can be increased to a certain extent, and the initial power of the Cr target is sequentially reduced, so that the content of Cr in the plurality of CrC layers is gradually reduced, and therefore the hardness of the plurality of CrC layers is gradually increased, the hardness transition is relatively smooth, the internal stress of the coating is small, and the adhesion of the coating is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical scheme in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0038] Figure 1 The flow chart of the preparation method of the GLC coating of the embodiment;

[0039] Figure 2 The scratch adhesion test results of the gear of embodiment 3. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0041] The embodiment of the present application provides a preparation method of a GLC (Graphite-like carbon) coating, which can solve the problem of poor adhesion of the coating in the related art.

[0042] As shown in the figure, the preparation method of the GLC coating of the embodiment includes the following steps: Figure 1

[0043] S1. The pretreated substrate is placed in a coating equipment for plasma cleaning.

[0044] S2. A Cr primer layer, a transition layer and a GLC layer doped with Cr are sequentially deposited on the surface of the cleaned substrate.

[0045] The transition layer includes a plurality of CrC layers sequentially deposited, each CrC layer is deposited by co-sputtering of a graphite target and a Cr target, the power of the graphite target is gradually increased, and the power of the Cr target is gradually reduced; and the initial power of the Cr target is sequentially reduced when the plurality of CrC layers are sequentially deposited.

[0046] The preparation method of the embodiment first places the pretreated substrate in a coating equipment for plasma cleaning, and then sequentially deposits a Cr primer layer, a transition layer and a GLC layer doped with Cr on the surface of the cleaned substrate. Since the transition layer includes a plurality of CrC layers sequentially deposited, each CrC layer is deposited by co-sputtering of a graphite target and a Cr target, the power of the graphite target is gradually increased, and the power of the Cr target is gradually reduced; and the initial power of the Cr target is sequentially reduced when the plurality of CrC layers are sequentially deposited. Therefore, as the power of the graphite target is gradually increased and the power of the Cr target is gradually reduced, the content of SP3 in the coating can be increased to a certain extent, and the initial power of the Cr target is sequentially reduced, so that the content of Cr in the plurality of CrC layers is gradually reduced. Therefore, the hardness of the plurality of CrC layers is gradually increased, the hardness transition is relatively smooth, the internal stress of the coating is small, and the adhesion of the coating is greatly improved.

[0047] Further, the pretreated substrate is placed in a coating equipment for plasma cleaning, which specifically includes the following steps:

[0048] First, the substrate is placed in an unbalanced magnetron coating furnace, vacuumized to 3x10 -5 Pa, and argon gas is introduced at a flow rate of 1-2 sccm. ​

[0049] Then, the power supply is started, the graphite target power is set to 0.1-0.15 kW, the Cr target power is set to 0.1-0.15 kW, and the substrate bias parameters are set as follows: the initial bias is 120 V, the final bias is 500-600 V, the voltage rising time is 60 s, and the voltage is kept unchanged after reaching the final bias for 14-19 min; the frequency of the bias power supply in this process is set to 200-250 kHz; at the same time, the linear ion source is turned on, and the linear ion source power supply parameters are set as follows: the initial voltage is 2000 V, the final voltage is 2800-3000 V, the voltage rising time is 60 s, and the voltage is kept unchanged after reaching the final voltage for 14-19 min, and the argon flow rate of the linear ion source is set to 20 sccm.

[0050] In this embodiment, the substrate rotation speed is set to 4 RPM, and the entire plasma cleaning process lasts for 15-20 min.

[0051] In this embodiment, by using the linear ion source to perform high-intensity etching on the substrate surface during the plasma cleaning process, the linear ion source voltage is as high as 2000-2800 V, and the argon ions generated thereby violently bombard the substrate surface under the acceleration of the voltage, which can effectively remove the oxide layer on the substrate surface and form a micro-texture on the substrate surface, thereby greatly improving the bonding strength of the coating.

[0052] On the basis of the above embodiment, in this embodiment, the conditions for depositing the Cr base layer on the cleaned substrate surface include:

[0053] The argon flow rate into the coating equipment is controlled to be 25-35 sccm, the initial power of the Cr target is adjusted to be 0.1 kW, and the initial bias of the substrate is 120 V; the Cr target power is kept unchanged after reaching the final power of 2.1-2.3 kW in the preset power rising time, and the substrate bias is kept unchanged after reaching the final bias of 60 V in the preset voltage falling time, and the frequency of the bias power supply is 200-250 kHz; the preset power rising time and the preset voltage falling time are the same; and the deposition time of the Cr base layer is 1100-1600 s.

[0054] Specifically, after the plasma cleaning, a Cr base layer is deposited on the substrate surface, and the process parameters are as follows: the argon flow rate into the unbalanced magnetic coating furnace is adjusted to be 25-35 sccm; the graphite target power supply is turned off, and the Cr target power supply parameters are adjusted as follows: the initial power is 0.1 kW, the final power is 2.1-2.3 kW, the power rising time is 30 s, and the power is kept unchanged after reaching the final power; the substrate bias is set as follows: the initial bias is 120 V, the final bias is 60 V, the voltage falling time is 30 s, and the voltage is kept unchanged after reaching the final bias; the frequency of the bias power supply in this process is set to 200-250 kHz. The entire process of the Cr base layer lasts for 1100-1600 s.

[0055] Further, from the direction close to the substrate to the direction away from the substrate, the multilayer CrC layer is respectively a first CrC layer, a second CrC layer and a third CrC layer, and the deposition time of each CrC layer is the same.

[0056] In this embodiment, after the Cr primer layer is completed, the first CrC layer is deposited on the surface of the substrate. The conditions for depositing the first CrC layer include:

[0057] The argon flow into the coating equipment is controlled at 25-35sccm; the graphite target power is turned on, the starting power of the graphite target is adjusted to 0.1kW, the end power is adjusted to 3.4-3.8kW, the power-up time is 2000-5000s, and the frequency of the graphite target power is set to 20-30kHz; the starting power of the Cr target is adjusted to 2.1-2.3kW, the end power is adjusted to 0.07-0.1kW, the power-down time is synchronized with the power-up time of the Cr target, and the time is 2000-5000s; the substrate bias is kept constant at 40V for 2000s-5000s, and the frequency of the bias power is 40-60kHz; the deposition time of the first CrC layer, the graphite target power-up time, and the Cr target power-down time are all 2000-5000s.

[0058] In this embodiment, after the first CrC layer is completed, the second CrC layer is deposited. The conditions for depositing the second CrC layer include:

[0059] The argon flow into the coating equipment is controlled at 25-35sccm, the graphite target power is turned on, the starting power of the graphite target is adjusted to 0.1kW, the end power is adjusted to 3.4-3.8kW, the power-up time is 2000-5000s, and the frequency of the graphite target power is set to 20-30kHz; the starting power of the Cr target is adjusted to 1.5-1.9kW, the end power is adjusted to 0.07-0.1kW; the substrate bias is 60V, the power-down time is synchronized with the power-up time of the Cr target, and the time is 2000-5000s; the frequency of the bias power is 40-60kHz, and the time is 2000s-5000s; the deposition time of the second CrC layer, the graphite target power-up time, and the Cr target power-down time are all 2000-5000s.

[0060] In this embodiment, after the second CrC layer is completed, the third CrC layer is deposited. The conditions for depositing the third CrC layer include:

[0061] The argon flow into the coating equipment is controlled at 25-35sccm, the graphite target power is turned on, the initial power of the graphite target is adjusted to 0.1kW, the terminal power is adjusted to 3.4-3.8kW, the power increasing time is 2000-5000s, and the frequency of the graphite target power is set to 20-30kHz; the initial power of the Cr target is adjusted to 1.0-1.4kW, the terminal power is adjusted to 0.07-0.1kW, the power decreasing time is synchronized with the power increasing time of the Cr target, and the time is 2000-5000s; the substrate bias is constant at 80V, the time is 2000s-5000s, and the frequency of the bias power is 40-60kHz; the deposition time of the third CrC layer, the power increasing time of the graphite target, and the power decreasing time of the Cr target are all 2000-5000s.

[0062] Based on the above-mentioned embodiments, in the present embodiment, the conditions for depositing the GLC layer doped with Cr include:

[0063] The argon flow into the coating equipment is controlled at 15-20sccm, the power of the graphite target is adjusted to 3.4-3.8kW, the power of the Cr target is adjusted to 0.07-1.0kW, the initial bias of the substrate is adjusted to 40V, and the terminal bias is adjusted to 100V; the frequency of the bias power is 40-60kHz.

[0064] The deposition time of the GLC layer is the same as the power increasing time of the substrate, and both are 9-15h.

[0065] Specifically, after depositing the transition layer, the outermost GLC coating layer is deposited on the surface of the substrate, and the process parameters are as follows: the argon flow into the furnace is 15-20sccm; the graphite target power is turned on, and the graphite target power parameters are adjusted as follows: the power of the graphite target is kept constant at 3.4-3.8kW, and the keeping time is 9-15h; the Cr target power parameters are adjusted as follows: the power of the Cr target is kept constant at 0.07-1.0kW, and the keeping time is 9-15h. The bias of the substrate is set as follows: the initial bias is 40V, the terminal bias is 100V, and the bias increasing time is 9-15h, and the frequency of the bias power during the process is set to 40-60kHz.

[0066] After depositing the GLC coating layer, the graphite target and the Cr target power are turned off, the argon flow is continuously maintained until the furnace temperature drops to room temperature, then the furnace door is opened, and the workpiece is taken out.

[0067] Preferably, the above-mentioned substrate is a high-speed heavy-duty gear; and the above-mentioned preparation method further comprises pretreating the high-speed heavy-duty gear, specifically including the following steps:

[0068] Firstly, the high-speed heavy-duty gear is subjected to carburizing treatment, and the carburizing layer depth is 0.8-1.1mm. The surface hardness is 58-63HRC.

[0069] Secondly, the high-speed heavy-duty gear after carburizing treatment is subjected to grinding treatment, and the roughness after grinding is controlled at Ra 0.2-0.4 μm.

[0070] Wherein, the gear after carburizing and quenching is subjected to grinding treatment, and the non-martensite structure on the surface of the gear caused by carburizing is removed.

[0071] Then, the high-speed heavy-duty gear after grinding treatment is subjected to abrasive flow treatment, and the surface roughness is controlled at Ra 0.07-0.1 μm. By polishing the surface of the gear, the roughness of the surface of the gear can be effectively controlled.

[0072] Finally, the oil stains on the surface of the high-speed heavy-duty gear are removed by ultrasonic cleaning, and the gear is dried.

[0073] Wherein, the oil stains on the surface of the gear are removed by ultrasonic cleaning; and then the gear after cleaning is subjected to drying treatment, so that the surface is free of water stains and oil stains.

[0074] The GLC coating and the preparation method thereof will be described below in combination with examples taking the high-speed heavy-duty gear as an example, but they cannot be understood as limiting the scope of protection of the present application.

[0075] Example 1

[0076] 1.1 Pretreatment of the gear

[0077] (1) Carburizing treatment: the gear is subjected to carburizing treatment, the carburizing layer depth is 0.8 mm, and the surface hardness is 58 HRC;

[0078] (2) Grinding treatment: the gear after carburizing and quenching is subjected to grinding treatment, the non-martensite structure on the surface of the gear caused by carburizing is removed, and the roughness after grinding is controlled at 0.4 μm;

[0079] (3) Polishing treatment of the surface of the gear: the gear after grinding is subjected to abrasive flow treatment, and the surface roughness of the gear is controlled at Ra 0.07 μm;

[0080] (4) Ultrasonic cleaning: the oil stains on the surface of the gear are removed by ultrasonic cleaning;

[0081] (5) Drying: the gear after cleaning is subjected to drying treatment, and the surface is free of water stains and oil stains;

[0082] 1.2 Preparation of GLC coating on the surface of the gear

[0083] (1) Plasma cleaning: the gear is placed in a non-equilibrium magnetron coating furnace, and vacuum is extracted to 3x10 -5Afterwards, argon gas was introduced into the furnace at a flow rate of 1 seem. Then the power was started, with the graphite target power source parameters set as: power 0.1 kW; the Cr target power source parameters set as: power 0.1 kW; the substrate bias set as: initial bias 120 V, final bias 500 V, bias rise time 60 s, and the bias was maintained for 14 min after reaching the final bias, with the bias power source frequency set as 200 kHz; the linear ion source was also started, with the linear ion source power source parameters set as: initial voltage 2000 V, final voltage 2800 V, voltage rise time 60 s, and the linear ion source was maintained for 14 min after reaching the final voltage, with the linear ion source argon gas flow rate set as 20 seem. The workpiece rotation speed was set as 4 RPM, and the entire plasma cleaning process lasted for 15 min.

[0084] (2) Cr undercoat layer: after plasma cleaning, a Cr undercoat layer was deposited on the gear surface, with the following process parameters: the argon gas flow rate introduced into the furnace was adjusted to 25 seem; the graphite target power source was turned off, and the Cr target power source parameters were adjusted as: initial power 0.1 kW, final power 2.1 kW, power rise time 30 s, and the power was maintained after reaching the final power. The substrate bias was set as: initial bias 120 V, final bias 60 V, bias fall time 30 s, and the bias was maintained after reaching the final bias, with the bias power source frequency set as 200 kHz. The entire Cr undercoat process lasted for 1100 s.

[0085] (3) Transition layer:

[0086] First CrC layer: after the Cr undercoat layer was completed, a first CrC layer was deposited on the gear surface, with the following process parameters: the argon gas flow rate introduced into the furnace was 25 seem; the graphite target power source was turned on, and the graphite target power source parameters were adjusted as: initial power 0.1 kW, final power 3.4 kW, power rise time 2000 s, and the graphite target power source frequency was set as 20 kHz; the Cr target power source parameters were adjusted as: initial power 2.1 kW, final power 0.07 kW, power fall time synchronized with the Cr target power rise time, and the time was 2000 s. The substrate bias was set as: bias maintained constant at 40 V for 2000 s, and the bias power source frequency was set as 40 kHz. The first CrC layer deposition process lasted for 2000 s.

[0087] Second CrC layer: After the first CrC layer is completed, a second CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 25 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.4 kW, the power-up time is 2000 s, and the graphite target power supply frequency is set to 20 kHz; the Cr target power supply parameters are adjusted as follows: the starting power is 1.5 kW, the end power is 0.07 kW, and the power-down time is synchronized with the Cr target power-up time, which is 2000 s. The substrate bias voltage is set to be constant at 60 V for 2000 s, and the frequency of the bias voltage power supply during the process is set to 40 kHz. The entire deposition process of the second CrC layer lasts for 2000 s.

[0088] Third CrC layer: After the second CrC layer is completed, a third CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 25 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.4 kW, the power-up time is 2000 s, and the graphite target power supply frequency is set to 20 kHz; the Cr target power supply parameters are adjusted as follows: the starting power is 1.0 kW, the end power is 0.07 kW, and the power-down time is synchronized with the Cr target power-up time, which is 2000 s. The substrate bias voltage is set to be constant at 80 V for 2000 s, and the frequency of the bias voltage power supply during the process is set to 40 kHz. The entire process of the third CrC layer lasts for 2000 s.

[0089] (4) Outermost GLC coating layer:

[0090] GLC layer: After the transition layer is deposited, the outermost GLC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 15 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the graphite target power is kept constant at 3.4 kW for 9 h; the Cr target power supply parameters are adjusted as follows: the Cr target power is kept constant at 0.07 kW for 9 h. The substrate bias voltage is set as follows: the starting bias voltage is 40 V, the end bias voltage is 100 V, and the voltage-up time is 9 h, and the frequency of the bias voltage power supply during the process is set to 40 kHz.

[0091] (5) Cooling and taking out the workpiece:

[0092] After the coating is prepared, the graphite target and Cr target power supplies are turned off, argon is continuously introduced until the furnace temperature drops to room temperature, the furnace door is opened, and the gear is taken out.

[0093] The GLC coating component prepared in this embodiment is mainly graphite-like SP2 component, the proportion of SP2 component is 65%, the proportion of SP3 component is 35%, the hardness of the coating is 15 Gpa, the elastic modulus is 150 Gpa, the coating bonding force is 80 N, the total thickness of the coating is 2.5 μm, the thickness of the Cr base layer is 0.4 μm, the thickness of each CrC layer of the transition layer is 0.2 μm, the thickness of the outermost GLC layer is 1.5 μm, and the dry friction coefficient of the coating is 0.1.

[0094] Example 2

[0095] 1.1 Gear pretreatment:

[0096] (1) Carburizing treatment: the gear is subjected to carburizing treatment, the carburized layer depth is 0.95 mm, and the surface hardness is 61 HRC;

[0097] (2) Gear grinding treatment: the carburized and quenched gear is subjected to gear grinding treatment to remove the non-martensite structure on the surface of the gear due to carburizing, and the roughness after grinding is controlled to be Ra 0.3 μm;

[0098] (3) Gear surface polishing treatment: the gear surface after grinding is subjected to abrasive flow treatment, and the gear surface roughness is controlled to be Ra 0.08 μm;

[0099] (4) Ultrasonic cleaning: ultrasonic cleaning is used to remove oil stains on the gear surface;

[0100] (5) Drying: the cleaned gear is subjected to drying treatment, and the surface is free of water stains and oil stains.

[0101] 1.2 Gear surface GLC coating preparation

[0102] (1) Plasma cleaning: the gear is placed in a non-equilibrium magnetron coating furnace, vacuumed to 3 x 10 -5 Pa, then argon gas is introduced into the furnace, the argon gas flow is 1.5 sccm. Then the power is started, wherein the graphite target power parameters are set as: power 0.13 kW; the Cr target power parameters are set as: power 0.13 kW; the substrate bias is set as: the initial bias is 120 V, the final bias is 550 V, the voltage rising time is 60 s, and after reaching the final bias, it is kept for 17 min, the frequency of the bias power source is set to 220 kHz; at the same time, the linear ion source is started, the linear ion source power parameters are set as: the initial voltage is 2000 V, the final voltage is 2900 V, the voltage rising time is 60 s, and after reaching the final bias, it is kept for 17 min, the argon gas flow of the linear ion source is set to 20 sccm. The workpiece rotation speed is set to 4 RPM, and the entire plasma cleaning process lasts for 18 min.

[0103] (2) Cr primer layer: After plasma cleaning, a layer of Cr primer layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is adjusted to 30 sccm; the graphite target power is turned off, and the Cr target power parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 2.2 kW, the power rising time is 30 s, and the end power is kept unchanged after reaching the end power. The substrate bias voltage is set as follows: the starting bias voltage is 120 V, the end bias voltage is 60 V, the voltage decreasing time is 30 s, and the end bias voltage is kept unchanged after reaching the end bias voltage. The frequency of the bias voltage power source in this process is set to 230 kHz. The entire process of Cr primer deposition lasts for 1400 s.

[0104] (3) Transition layer:

[0105] First CrC layer: After the completion of the Cr primer layer, a first CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 30 sccm; the graphite target power is turned on, and the graphite target power parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.6 kW, the power rising time is 3500 s, and the graphite target power frequency is set to 25 kHz; the Cr target power parameters are adjusted as follows: the starting power is 2.2 kW, the end power is 0.08 kW, and the power decreasing time is synchronized with the Cr target power rising time, which is 3500 s. The substrate bias voltage is set as follows: the bias voltage is kept constant at 40 V for 3500 s, and the frequency of the bias voltage power source in this process is set to 50 kHz. The deposition process of the first CrC layer lasts for 3500 s.

[0106] Second CrC layer: After the completion of the first CrC layer, a second CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 30 sccm; the graphite target power is turned on, and the graphite target power parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.6 kW, the power rising time is 3500 s, and the graphite target power frequency is set to 25 kHz; the Cr target power parameters are adjusted as follows: the starting power is 1.7 kW, the end power is 0.08 kW, and the power decreasing time is synchronized with the Cr target power rising time, which is 3500 s. The substrate bias voltage is set as follows: the bias voltage is kept constant at 60 V for 3500 s, and the frequency of the bias voltage power source in this process is set to 50 kHz. The entire deposition process of the second CrC layer lasts for 3500 s.

[0107] Third CrC layer: after the second CrC layer is completed, a third CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 30 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.6 kW, the power-up time is 3500 s, and the graphite target power supply frequency is set to 25 kHz; the Cr target power supply parameters are adjusted as follows: the starting power is 1.2 kW, the end power is 0.08 kW, and the power-down time is synchronized with the Cr target power-up time, which is 3500 s. The substrate bias voltage is set to be constant at 80 V for 3500 s, and the frequency of the bias voltage power supply in this process is set to 50 kHz. The entire process duration of the third CrC layer is 3500 s.

[0108] (4) Outermost GLC coating layer:

[0109] GLC layer: after the transition layer is deposited, the outermost GLC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 18 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the graphite target power is kept constant at 3.6 kW for 13 h; the Cr target power supply parameters are adjusted as follows: the Cr target power is kept constant at 0.08 kW for 13 h. The substrate bias voltage is set as follows: the starting bias voltage is 40 V, the end bias voltage is 100 V, and the voltage-up time is 13 h, and the frequency of the bias voltage power supply in this process is set to 50 kHz.

[0110] (5) Cooling and taking out the workpiece:

[0111] After the coating is prepared, the graphite target and Cr target power supplies are turned off, argon is continuously introduced until the furnace temperature drops to room temperature, the furnace door is opened, and the gear is taken out.

[0112] The GLC coating prepared in this example mainly contains graphite-like SP2 components, the proportion of SP2 components is 75%, the proportion of SP3 components is 25%, the hardness of the coating is 14 Gpa, the elastic modulus is 120 Gpa, the coating adhesion is 85 N, the total thickness of the coating is 3.0 μm, the thickness of the Cr base layer is 0.45 μm, the thickness of each CrC layer in the transition layer is 0.3 μm, the thickness of the outermost GLC layer is 1.65 μm, and the dry friction coefficient of the coating is 0.085.

[0113] Example 3

[0114] 1.1 Gear pretreatment:

[0115] (1) Carburizing treatment: the gear is subjected to carburizing treatment, the carburized layer depth is 1.1 mm, and the surface hardness is 63 HRC;

[0116] (2) Gear grinding treatment: grinding treatment is performed on the carburized and quenched gear to remove the non-martensite structure on the gear surface caused by carburizing. The roughness after grinding is controlled to be Ra0.2 μm;

[0117] (3) Gear surface polishing treatment: abrasive flow treatment is performed on the gear surface after grinding. The gear surface roughness is controlled to be Ra0.1 μm;

[0118] (4) Ultrasonic cleaning: ultrasonic cleaning is used to remove oil stains on the gear surface;

[0119] (5) Drying: the cleaned gear is subjected to drying treatment. There should be no water stains and oil stains on the surface.

[0120] 1.2 Preparation of GLC coating on gear surface

[0121] (1) Plasma cleaning: the gear is placed in a non-equilibrium magnetron coating furnace, and vacuum is extracted to 3x10 -5 Pa, and then argon gas is introduced into the furnace at a flow rate of 2sccm. Then the power is started, wherein the graphite target power parameters are set as: power 0.15kW; the Cr target power parameters are set as: power 0.15kW; the substrate bias is set as: the initial bias is 120V, the final bias is 600V, the voltage rising time is 60s, and the process bias power frequency is set to 250kHz after reaching the final bias for 19min; at the same time, the linear ion source is started, and the linear ion source power parameters are set as: the initial voltage is 2000V, the final voltage is 3000V, the voltage rising time is 60s, and the linear ion source argon flow rate is set to 20sccm after reaching the final bias for 19min. The workpiece rotation speed is set to 4RPM, and the entire plasma cleaning process lasts for 20min.

[0122] (2) Cr primer layer: after plasma cleaning, a layer of Cr primer layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is adjusted to 35sccm; the graphite target power is turned off, and the Cr target power parameters are adjusted as follows: the initial power is 0.1kW, the final power is 2.3kW, the power rising time is 30s, and the process remains unchanged after reaching the final power. The substrate bias is set as: the initial bias is 120V, the final bias is 60V, the voltage falling time is 30s, and the process remains unchanged after reaching the final bias. The frequency of the bias power source during the process is set to 250kHz. The entire process of Cr primer lasts for 1600s.

[0123] (3) Transition layer:

[0124] First CrC layer: After the completion of the Cr base layer, a first CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate into the furnace is 35 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.8 kW, the power-up time is 5000 s, and the graphite target power supply frequency is set to 30 kHz; the Cr target power supply parameters are adjusted as follows: the starting power is 2.3 kW, the end power is 0.1 kW, the power-down time is synchronized with the Cr target power-up time, and the time is 5000 s. The substrate bias voltage is set as follows: the bias voltage is kept constant at 40 V for 5000 s, and the frequency of the bias voltage power supply in this process is set to 60 kHz. The entire process duration of the first CrC layer is 5000 s.

[0125] Second CrC layer: After the completion of the first CrC layer, a second CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate into the furnace is 35 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.8 kW, the power-up time is 5000 s, and the graphite target power supply frequency is set to 30 kHz; the Cr target power supply parameters are adjusted as follows: the starting power is 1.9 kW, the end power is 0.1 kW, the power-down time is synchronized with the Cr target power-up time, and the time is 5000 s. The substrate bias voltage is set as follows: the bias voltage is kept constant at 60 V for 5000 s, and the frequency of the bias voltage power supply in this process is set to 60 kHz. The entire deposition process duration of the second CrC layer is 5000 s.

[0126] Third CrC layer: After the completion of the second CrC layer, a third CrC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate into the furnace is 35 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the starting power is 0.1 kW, the end power is 3.8 kW, the power-up time is 5000 s, and the graphite target power supply frequency is set to 30 kHz; the Cr target power supply parameters are adjusted as follows: the starting power is 1.4 kW, the end power is 0.1 kW, the power-down time is synchronized with the Cr target power-up time, and the time is 5000 s. The substrate bias voltage is set as follows: the bias voltage is kept constant at 80 V for 5000 s, and the frequency of the bias voltage power supply in this process is set to 60 kHz. The entire process duration of the third CrC layer is 5000 s.

[0127] (4) Outermost GLC coating layer:

[0128] GLC layer: after the deposition of the transition layer, the outermost GLC layer is deposited on the gear surface, and the process parameters are as follows: the argon flow rate introduced into the furnace is 20 sccm; the graphite target power supply is turned on, and the graphite target power supply parameters are adjusted as follows: the graphite target power is kept constant at 3.8 kW, and the holding time is 15 h; the Cr target power supply parameters are adjusted as follows: the Cr target power is kept constant at 1.0 kW, and the holding time is 15 h. The substrate bias voltage is set as follows: the initial bias voltage is 40 V, the final bias voltage is 100 V, and the voltage rising time is 15 h. The frequency of the bias voltage power supply in this process is set to 60 kHz.

[0129] (5) Cooling and taking out the workpiece:

[0130] After the coating is prepared, the graphite target and Cr target power supplies are turned off, the argon gas is continuously introduced until the furnace temperature drops to room temperature, the furnace door is opened, and the gear is taken out. The scratch adhesion of the gear is tested by nanoindentation, and the test results are shown in Figure 2 When the load is 93.4 N, the gear surface coating film is broken.

[0131] The GLC coating prepared in this embodiment is mainly composed of graphite-like SP2 components, with a SP2 component ratio of 85% and a SP3 component ratio of 15%. The hardness of the coating is 13 Gpa, the elastic modulus is 90 Gpa, the coating adhesion is 93 N, the total thickness of the coating is 3.5 μm, the thickness of the Cr base layer is 0.5 μm, the thickness of each CrC layer in the transition layer is 0.4 μm, the thickness of the outermost GLC coating is 1.8 μm, and the dry friction coefficient of the coating is 0.07.

[0132] In this embodiment, a wear-reducing and noise-reducing GLC coating is prepared on the surface of a carburized gear. The coating is mainly composed of graphite-like SP2 components, with a SP2 component ratio of 65-85% and a SP3 component ratio of 35-15%. The hardness of the coating is 13-15 Gpa, the elastic modulus is 90-150 Gpa, the coating adhesion is 80-93 N, the total thickness of the coating is 2.5-3.5 μm, the thickness of the Cr base layer is 0.4-0.5 μm, the thickness of each CrC layer in the transition layer is 0.2-0.4 μm, the thickness of the outermost GLC coating is 1.5-1.8 μm, and the dry friction coefficient of the coating is 0.07-0.1. Not only the wear-reducing effect is good, but also the coating adhesion is high, which can be above 80 N, and the highest can be above 90.

[0133] The ideal transition layer is obtained by the simplest monodoping, i.e. doping Cr element; the deposition time of each CrC layer is slightly different, and the process parameters of the graphite target are also different, but the initial power of the Cr target is different. The initial power of the Cr target of the first CrC layer, the second CrC layer and the third CrC layer is sequentially reduced, and is 2.1-2.3 kW, 1.5-1.9 kW and 1.0-1.4 kW respectively, so that the Cr content is gradually reduced, the hardness is gradually increased, and the hardness of the three layers is about 8 GPa, 10 GPa and 12 GPa respectively, and the thickness is not different, and is 0.2-0.4 μm, so that the hardness transition between each CrC layer is relatively smooth, the stress is small, and the adhesion of the coating is greatly improved.

[0134] In addition, each CrC layer is a composition transition, specifically, the C target power of each layer is gradually increased from 0.1 kW to 3.4-3.8 kW, the Cr target power is reduced from the initial power of each layer to 0.07-0.1 kW, and the substrate bias is 40 V, 60 V and 80 V respectively, so that the SP3 composition in each transition layer is gradually increased, the Cr content is gradually reduced, the hardness is gradually increased, and the stress of each layer is also small.

[0135] The GLC layer of the outermost layer of the gear, the bias is set to gradually increase from 40 V to 100 V, and the Cr target power is maintained at the final value of the Cr target power of the previous transition layer, i.e. 0.07-1 kW, the Cr content of this layer is lower than that of the transition layer, so the hardness of this layer is the highest, which is 13-15 GPa, and since the bias is gradually increased from 40 V to 100 V, the hardness of the outermost layer is also gradually increased, and the overall stress is low.

[0136] The application also provides an embodiment of a GLC coating prepared by the above preparation method.

[0137] The GLC coating of the embodiment is suitable for the preparation method of each GLC coating described above, and the hardness is smoothly transitioned by substrate roughness control, bias transition and composition transition, thereby reducing the stress of the coating and improving the adhesion between the coatings and between the coating and the substrate.

[0138] In the description of the present application, it should be noted that the terms "upper", "lower", and the like are used for indicating the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise expressly specified and limited, the terms "mount", "connect", "connection" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0139] It should be noted that in the present application, relational terms such as "first" and "second", and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or equipment including the element.

[0140] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A method for preparing a GLC coating, characterized in that: It includes the steps of: The pretreated substrate is placed in the coating equipment for plasma cleaning; A Cr primer layer, a transition layer, and a Cr-doped GLC layer are sequentially deposited on the cleaned substrate surface; The transition layer includes multiple CrC layers deposited in sequence, each CrC layer is deposited by co-sputtering a graphite target and a Cr target, and the power of the graphite target is gradually increased and the power of the Cr target is gradually reduced; When multiple CrC layers are deposited sequentially, the starting power of the Cr target decreases sequentially; The multiple CrC layers are the first CrC layer, the second CrC layer and the third CrC layer, and the deposition time of each CrC layer is the same; The conditions for depositing the first CrC layer include: The argon flow rate into the coating equipment was controlled at 25-35 sccm. The starting power of the graphite target was adjusted to 0.1 kW and the end power was adjusted to 3.4-3.8 kW. The starting power of the Cr target was adjusted to 2.1-2.3 kW and the end power was adjusted to 0.07-0.1 kW. The substrate bias voltage was 40 V, and the frequency of the bias power supply was 40-60 kHz. The deposition time of the first CrC layer, the graphite target power-up time, and the Cr target power-down time were all 2000-5000 seconds. The conditions for depositing the second CrC layer include: The argon flow rate into the coating equipment was controlled at 25-35 sccm. The starting power of the graphite target was adjusted to 0.1 kW and the end power was adjusted to 3.4-3.8 kW. The starting power of the Cr target was adjusted to 1.5-1.9 kW and the end power was adjusted to 0.07-0.1 kW. The substrate bias voltage was 60 V, and the frequency of the bias power supply was 40-60 kHz. The deposition time of the second CrC layer, the graphite target power-up time, and the Cr target power-down time were all 2000-5000 seconds. The conditions for depositing the third CrC layer include: The argon flow rate entering the coating equipment was controlled at 25-35 sccm, the starting power of the graphite target was adjusted to 0.1 kW, and the end power was adjusted to 3.4-3.8 kW; the starting power of the Cr target was adjusted to 1.0-1.4 kW, and the end power was adjusted to 0.07-0.1 kW; the substrate bias was 80 V, and the frequency of the bias power supply was 40-60 kHz; the deposition time of the third CrC layer, the graphite target power-up time, and the Cr target power-down time were all 2000-5000 s.

2. The method for preparing the GLC coating according to claim 1, wherein: The conditions for depositing a Cr primer layer on the cleaned substrate surface include: The argon flow rate into the coating equipment was controlled at 25-35 sccm, and the starting power of the Cr target was adjusted to 0.1 kW and the starting bias voltage of the substrate was adjusted to 120 V. The Cr target power is controlled to remain unchanged after reaching an end power of 2.1-2.3 kW within a preset power-up time, and the substrate bias voltage is controlled to remain unchanged after reaching an end bias of 60 V within a preset voltage-down time, and the frequency of the bias power supply is 200-250 kHz; the preset power-up time is the same as the preset voltage-down time; The deposition time of the Cr base layer is 1100-1600s.

3. The method for preparing the GLC coating according to claim 1, wherein: The conditions for depositing the Cr-doped GLC layer include: The argon flow rate into the coating equipment was controlled at 15-20 sccm, and the graphite target power was adjusted to 3.4-3.8 kW, the Cr target power to 0.07-1.0 kW, the substrate starting bias to 40 V, and the end bias to 100 V; the bias power frequency was 40-60 kHz; The deposition time of the GLC layer is the same as the pressurization time of the substrate, which is 9-15h.

4. The method for preparing the GLC coating according to claim 1, wherein: The pre-treated substrate is placed in the coating equipment for plasma cleaning, which specifically includes: The substrate was placed in an unbalanced magnetron coating furnace and vacuumed to 3×10 -5 After Pa, argon gas was introduced at a flow rate of 1-2 sccm; Set the graphite target power to 0.1-0.15kW, the Cr target power to 0.1-0.15kW, and the substrate bias parameters to: starting bias to 120V, end bias to 500-600V, ramp time to 60s, and maintain the bias constant after reaching the end bias; Turn on the linear ion source and set the linear ion source power supply parameters as follows: starting voltage of 2000 V, end voltage of 2800-3000 V, ramp time of 60 s, and keep the voltage constant after reaching the end voltage. Set the argon flow rate of the linear ion source to 20 sccm. The substrate speed was set to 4 RPM, and the plasma cleaning time was 15-20 min.

5. The method for preparing the GLC coating according to claim 1, wherein: The substrate is a high-speed heavy-load gear; the method further includes pre-processing the high-speed heavy-load gear, specifically including: Carburizing treatment is performed on high-speed and heavy-load gears, with a carburizing layer depth of 0.8-1.1mm; The high-speed heavy-load gears after carburizing are ground, and the roughness after grinding is controlled at Ra0.2-0.4μm; Perform abrasive flow treatment on the surface of high-speed heavy-load gears after gear grinding, and control the surface roughness to Ra0.07-0.1μm; Ultrasonic cleaning is used to remove oil stains on the surface of high-speed and heavy-loaded gears and then drying is performed.

6. A GLC coating, characterized in that: The GLC coating is prepared by the preparation method according to claim 1.

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