A craltisi n coating and a method for producing the same

Abstract

The present disclosure relates to a CrAlTiSiN coating and a preparation method thereof, comprising the following steps: S1. introducing N2 into a coating chamber, starting a Cr target, and depositing a CrN transition layer on a substrate; S2. continuing to introduce N2, closing the Cr target, starting a Cr 50 Al 50 target and a TiSi target, and depositing CrAl and TiSi on the substrate under the condition that the N2 flow rate is 100-300 sccm to obtain a CrAlTiSiN coating; wherein the bias voltage of the Cr 50 Al 50 target is -100 to -90 V, and the current is 110-130 A; the bias voltage of the TiSi target is -120 to -100 V, and the current is 80-160 A. When Ti=16.41 at.% and Si=5.70 at.% in the prepared CrAlTiSiN coating, the CrAlTiSiN coating has the best crystallinity and the most compact microstructure, the hardness, elastic modulus and fracture toughness of the CrAlTiSiN coating are all improved, the measured values are 35.9 GPa, 294.1 GPa and 1.53 MPa·m 1 / 2 , respectively, the internal stress of the coating is -0.34 GPa, the corrosion potential of the coating moves to the positive direction, the corrosion current density value is 1.60×10 ‑8 A·cm ‑2 , and the CrAlTiSiN coating has the best corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of coating, in particular to a CrAlTiSiN coating and a preparation method thereof. BACKGROUND

[0002] CrN coating is widely used in automobile die, cutting tool and easy-wearing parts due to its advantages of friction and wear resistance and corrosion resistance, but its application is limited in a certain range due to low hardness, large friction resistance and relatively weak corrosion resistance. At present, the ternary CrAlN coating has been improved to a certain extent in terms of comprehensive performance compared with CrN coating.

[0003] In recent years, researchers have found that the doped coating presents typical nanocrystalline and amorphous structure by doping Si, B and other non-metallic elements in CrAlN coating. Silicon nitride (Si3N4) is a ceramic phase with high hardness and high brittleness, but the three-dimensional network structure of Si3N4 is different from that of general ceramic materials, which has low thermal expansion coefficient, high elastic modulus and high strength, and the nitride of silicon (SiN x ) is the most stable structure.

[0004] The CrAlSiN coating with different Si contents was studied, and the microstructure of the coating was composed of (Cr, Al) N microcrystals and amorphous Si3N4 phase. With the increase of Si content, the corrosion resistance of CrAlSiN coating gradually improved, and the main reason was that the passivation layer formed on the surface of the coating would hinder the penetration of corrosive medium into the substrate, thereby improving the corrosion resistance of CrAlSiN coating.

[0005] Some researchers also prepared CrAlTiN and CrAlTiSiN coatings by multi-arc ion plating technology. Comparative analysis found that the hardness of CrAlTiN was 29 GPa, and the hardness of CrAlTiSiN coating increased with the content of Si, and the maximum hardness was 37 GPa, the friction coefficient was 0.58, and the film-substrate adhesion was more than 50 N. The cutting performance of CrAlTiSiN coating was significantly improved than that of CrAlTiN. The main reason for the increase of hardness of CrAlTiSiN coating is that the amorphous Si3N4 structure of Si element wraps the nanocrystalline CrAlN, causing solid solution strengthening and fine grain strengthening caused by Si element doping, thereby improving the hardness of the coating.

[0006] Therefore, the doping of elements has a significant effect on the performance of CrAlN coating. SUMMARY

[0007] Based on this, the purpose of the present disclosure is to further improve the properties of CrAlN coating by doping, so as to make it more widely used.

[0008] To achieve the above object, the present disclosure provides the following technical solutions:

[0009] A preparation method of a CrAlTiSiN coating, comprising the following steps:

[0010] S1. In the film coating chamber, N2 is introduced, the Cr target is started, and a CrN transition layer is deposited on the substrate;

[0011] S2. Continue to introduce N2, turn off the Cr target, start the CrAl target and the TiSi target, and deposit CrAl and TiSi on the substrate under the condition that the N2 flow is 100-300 sccm to obtain a CrAlTiSiN coating;

[0012] Preferably, in step S1, the bias voltage of the Cr target is-100 V, the current is 60 A, and the deposition time is 10 min.

[0013] Preferably, in step S2, the current of the TiSi target is 80 A, 100 A, 120 A, 140 A, or 160 A.

[0014] More preferably, in step S2, the deposition time is 30 min; the bias voltage of the CrAl target is-80 V, and the target current is 120 A; the bias voltage of the TiSi target is-100 V, and the target current is 140 A; and the flow of N2 is 200 sccm.

[0015] Preferably, it further comprises a step of cleaning the substrate before step S1.

[0016] More preferably, it further comprises a step of heating the film coating chamber to remove contaminants before step S1.

[0017] More preferably, it further comprises a step of introducing Ar to etch the surface of the substrate before step S1.

[0018] More preferably, the film coating chamber is heated to 400-500℃ before step S1.

[0019] More preferably, the film coating chamber is heated to 400-500℃ before step S1.

[0020] The surface of the substrate is etched by introducing Ar under the condition that the bias voltage is-400 V for 20 min.

[0021] To achieve the above object, the present disclosure further provides the following technical solutions:

[0022] A CrAlTiSiN coating obtained by the preparation method of any one of the preceding embodiments; in the CrAlTiSiN coating, the content of Ti is 9-21 at.%, and the content of Si is 4-12 at.%.

[0023] Preferably, the content of Ti is 16.41 at.%, and the content of Si is 5.70 at.%.

[0024] The technical solution claimed in the present disclosure has the following beneficial effects:

[0025] When the CrAlTiSiN coating obtained by the preparation is Ti=16.41 at.% and Si=5.70 at.%, the CrAlTiSiN coating has the best crystallinity and the most compact structure, and the hardness, elastic modulus and fracture toughness of the CrAlTiSiN coating are all improved, and the measured values are 35.9 GPa, 294.1 GPa and 1.53 MPa·m 1 / 2 , respectively, the internal stress of the coating is -0.34 GPa, the corrosion potential of the coating moves to the positive direction, and the corrosion current density value is 1.60 x 10 -8 A·cm -2 , indicating that the CrAlTiSiN coating has the best corrosion resistance. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0027] Figure 1 SEM surface scanning element distribution diagrams of CrAlTiSiN coatings with different TiSi contents: (a) #1: Ti=10.42 at.%, Si=11.66 at.%, (b) #2: Ti=11.97 at.%, Si=8.00 at.%, (c) #3: Ti=14.06 at.%, Si=6.16 at.%, (d) #4: Ti=16.41 at.%, Si=5.70 at.%, (e) #5: Ti=20.60 at.%, Si=4.35 at.%.

[0028] Figure 2Influence of different TiSi contents on the surface morphology of CrAlTiSiN coatings: (a) #1 : Ti = 10.42 at.%, Si = 11.66 at.%, (b) #2: Ti = 11.97 at.%, Si = 8.00 at.%, (c) #3: Ti = 14.06 at.%, Si = 6.16 at.%, (d) #4: Ti = 16.41 at.%, Si = 5.70 at.%, (e) #5: Ti = 20.60 at.%, Si = 4.35 at.%.

[0029] Figure 3 XRD patterns of CrAlTiSiN coatings with different TiSi contents.

[0030] Figure 4 HRTEM cross-sectional morphology of CrAlTiSiN coating with Ti = 16.41 at.% and Si = 5.70 at.%, (a) low magnification, (b) high magnification and selected area electron diffraction pattern.

[0031] Figure 5 Hardness and elastic modulus of CrAlTiSiN coatings with different TiSi contents.

[0032] Figure 6 Stress variation curve of CrAlTiSiN coatings with different TiSi contents.

[0033] Figure 7 Berkovich indentation morphology of CrAlTiSiN coatings with different TiSi contents at a penetration depth of 2400 nm: (a) #1 : Ti = 10.42 at.%, Si = 11.66 at.%, (b) #2: Ti = 11.97 at.%, Si = 8.00 at.%, (c) #3: Ti = 14.06 at.%, Si = 6.16 at.%, (d) #4: Ti = 16.41 at.%, Si = 5.70 at.%, (e) #5: Ti = 20.60 at.%, Si = 4.35 at.%.

[0034] Figure 8 Fracture toughness of CrAlTiSiN coatings as a function of total TiSi content.

[0035] Figure 9 Polarization curves of CrAlTiSiN coatings with different TiSi contents in 3.5 wt.% NaCl solution. DETAILED DESCRIPTION

[0036] To make the purposes, technical solutions, and beneficial effects of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present disclosure.

[0037] Embodiments

[0038] The coating instrument used in the present embodiment is a multi-arc ion coating instrument, and the target materials used are Cr target, TiSi target, and Cr 50 Al 50 alloy target, and the purity of the target materials is 99.99%. The TiSi target and the Cr 50 Al 50 alloy target are respectively installed on opposite sides of the vacuum chamber. High-purity argon (Ar) and nitrogen (N2) are used as working gases. In the vacuum chamber, the distance between each target material and the substrate is the same, and the distance is 240 mm.

[0039] In the coating experiment, the substrate is installed on a rotating support, which rotates at a speed of 6 rpm. The substrate material selected in the present embodiment is a polished 316 stainless steel sheet and a pure Si sheet. The stainless steel sheet with a size of 20 mm x 20 mm x 1 mm is used for performance characterization such as mechanical properties and corrosion resistance, and the pure Si sheet with a size of 20 mm x 5 mm x 1 mm is used for coating thickness testing.

[0040] The preparation process of the CrAlTiSiN coating in the present embodiment is as follows:

[0041] 1) Experimental sample cleaning step: the polished stainless steel sheet and Si sheet are respectively placed in beakers containing propanol and anhydrous ethanol and ultrasonically cleaned for at least 30 min, and then dried and installed in the vacuum chamber;

[0042] 2) The chamber is vacuumed to 2.0 x 10 -3 Pa, and before the coating experiment, the temperature of the vacuum chamber is heated to 450°C, which aims to eliminate small liquid and solid contaminants on the surface of the vacuum chamber and the substrate;

[0043] 3) High-purity Ar is introduced, and the bias power is turned on to -400 V. The surface of the substrate is etched for 20 min by introducing Ar to remove impurities on the substrate. Then, the bias voltage is lowered to -100 V, and Ar is continuously introduced for 2 min;

[0044] 4) Close the Ar inlet N2, open the Cr target, under the condition of deposition bias of -100 V, target current of 60 A, prepare CrN transition layer, wherein the deposition time is 10 min, the purpose of preparing CrN transition layer is to facilitate to improve the adhesion between the film layers;

[0045] 5) Continue to introduce N2, close the Cr target, start the Cr 50 Al 50 target and TiSi target, under the condition of N2 flow of 100 to 300 sccm, deposit CrAl and TiSi on the substrate to obtain CrAlTiSiN coating, the deposition time is 30 min, and finally the sample is cooled to room temperature in the furnace and taken out.

[0046] Among them, the bias voltage of the Cr 50 Al 50 target is -100 to -90 V, and the current is 110 to 130 A; the bias voltage of the TiSi target is -120 to -100 V, and the current of the TiSi target is 80 to 160 A.

[0047] In the preferred scheme, the current of the TiSi target is respectively set to 80 A, 100 A, 120 A, 140 A and 160 A.

[0048] In the more preferred scheme, the bias voltage of the Cr 50 Al 50 target is -80 V, and the target current is 120 A; the bias voltage of the TiSi target is -100 V, and the flow of N2 is 200 sccm.

[0049] In the present embodiment, when the bias voltage of the Cr 50 Al 50 target is -80 V, the target current is 120 A, the bias voltage of the TiSi target is -100 V, and the flow of N2 is 200 sccm, the current of the TiSi target is respectively set to 80 A, 100 A, 120 A, 140 A and 160 A, and the CrAlTiSiN coating with TiSi content of (#1) Ti = 10.42 at.%, Si = 11.66 at.%, (#2) Ti = 11.97 at.%, Si = 8.00 at.%, (#3) Ti = 14.06 at.%, Si = 6.16 at.%, (#4) Ti = 16.41 at.%, Si = 5.70 at.%, and (#5) Ti = 20.60 at.%, Si = 4.35 at.% can be obtained.

[0050] The performance of each CrAlTiSiN coating sample obtained was characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), coating stress tester, nanoindenter, and electrochemical corrosion test.

[0051] Figure 1 SEM surface scanning element distribution of CrAlTiSiN coatings with different TiSi contents is shown. The distribution of each element in the CrAlTiSiN coatings with different TiSi contents is relatively uniform. Figure 2 The effect of TiSi content on the surface morphology of CrAlTiSiN coatings is shown. When Ti = 16.41 at.%, Si = 5.70 at.%, the CrAlTiSiN coating has the smallest surface roughness and the most compact structure, indicating that reasonable control of TiSi content improves the surface compactness and surface porosity of the CrAlN-based coating.

[0052] Figure 3 XRD patterns of CrAlTiSiN coatings with different TiSi contents are shown. The results show that the CrAlTiSiN coatings obtained in this embodiment have FCC structure, and the preferred orientation is CrN (111), (200). Figure 4 The HRTEM cross-sectional morphology of the CrAlTiSiN coating when Ti = 16.41 at.%, Si = 5.70 at.% is shown, indicating that the CrAlTiSiN coating under this condition has good crystallization performance.

[0053] Figures 5 to 8 The hardness and elastic modulus, internal stress, Berkovich indentation morphology, and fracture toughness of the CrAlTiSiN coatings with different TiSi contents are shown. From the above results, when Ti = 16.41 at.%, Si = 5.70 at.%, the hardness, elastic modulus, and fracture toughness of the CrAlTiSiN coating are all improved, being 35.9 GPa, 294.1 GPa, and 1.53 MPa·m 1 / 2 , respectively, and the internal stress of the coating is -0.34 GPa.

[0054] Figure 9 The polarization curves of the CrAlTiSiN coatings with different TiSi contents in 3.5 wt.% NaCl solution are shown. When Ti = 16.41 at.%, Si = 5.70 at.%, the corrosion potential of the CrAlTiSiN coating moves to the positive direction, and the maximum corrosion current density is the smallest, being 1.60×10 -8 A·cm -2 , indicating that the CrAlTiSiN coating has the best corrosion resistance under this process parameter.

[0055] The coating obtained in the embodiment can be used in surface protection of cutting tools and mechanical friction parts, and can improve the surface performance and service life of the tools and parts. The preparation method has the advantages of simple process, fast deposition speed, low cost, high bonding strength, etc.

[0056] Comparative Example

[0057] The comparative example provides preparation of a CrAlN coating.

[0058] The coating instrument used in the comparative example is a multi-arc ion coating instrument, and the target materials used are Cr target and Cr 50 Al 50 alloy target, and the purity of the target materials is 99.99%. The two target materials are respectively installed on opposite sides of the vacuum chamber. High-purity argon (Ar) and nitrogen (N2) are used as working gases. In the vacuum chamber, the distance between each target and the substrate is the same, and the distance is 250 mm. In the coating experiment, the substrate is installed on a rotating support and rotates at a speed of 6 rpm. The substrate materials selected in the embodiment are polished 316 stainless steel sheets and pure Si sheets, wherein the stainless steel sheets with a size of 20 mm x 20 mm x 1 mm are used for performance characterization such as mechanical properties and corrosion resistance, and the film thickness of the coating is tested using a pure Si sheet with a size of 20 mm x 5 mm x 1 mm.

[0059] In the embodiment, the preparation process of the CrAlN coating is as follows:

[0060] 1) Sample cleaning step: the polished stainless steel sheets and Si sheets are respectively placed in beakers containing propanol and anhydrous ethanol and ultrasonically cleaned for at least 30 min, and then dried and installed in the vacuum chamber;

[0061] 2) The chamber is vacuumed to 2.0 x 10 -3 Pa, and before the coating experiment, the temperature of the vacuum chamber is heated to 450°C to eliminate small liquid and solid contaminants on the surface of the vacuum chamber and the substrate;

[0062] 3) High-purity Ar is introduced, and the bias power is turned on to -400 V. The surface of the substrate is etched for 20 min by introducing Ar to remove impurities on the substrate, and then the bias voltage is lowered to -100 V, and Ar is continuously introduced for 2 min;

[0063] 4) Close the Ar and introduce N2, and start the Cr target. The CrN transition layer is prepared under the conditions of a deposition bias of -100 V and a target current of 60 A, and the deposition time is 10 min. The purpose of preparing the CrN transition layer is to facilitate the improvement of the bonding strength between the film layers;

[0064] 5) Continue to introduce N2, close the Cr target, and start the Cr 50 Al50 The target was used to deposit CrAl on the substrate under the conditions of bias voltage -80 V, arc current 120 A, N2 flow rate 200 sccm, and deposition time 40 min, and the last sample was taken out after furnace cooling to room temperature.

[0065] The measured maximum hardness, elastic modulus and fracture toughness of the CrAlN coating were 30.7 GPa, 290.7 GPa and 1.41 MPa·m 1 / 2 , respectively, the minimum internal stress was 0.32 GPa, and the corrosion current density was 6.65×10 -8 A·cm -2 . Compared with the CrAlN coating, the hardness of the CrAlTiSiN coating with Ti = 16.41 at. % and Si = 5.70 at. % increased by 5.9 GPa, the elastic modulus and fracture toughness values increased, and the corrosion current density decreased significantly. This indicates that the doping of TiSi effectively improves the performance of the CrAlN coating.

[0066] The above-described embodiments are merely exemplary descriptions of the present disclosure and do not limit the scope of the present disclosure. Without departing from the design spirit of the present disclosure, various modifications and improvements to the technical solutions of the present disclosure made by those of ordinary skill in the art shall fall within the protection scope of the present disclosure as determined by the claims.

Claims

1. A method for producing a CrAlTiSiN coating, characterized in that The method comprises the following steps: S1. Introducing N2 into a coating chamber, starting a Cr target, and depositing a CrN transition layer on a substrate; S2. Continue N2flow, turn off Cr target, start Cr 50 Al 50 TiSi target, and deposit CrAl and TiSi on the substrate under a N2flow of 200 seem to obtain a CrAlTiSiN coating; In step S2, the Cr 50 Al 50 The bias voltage of the target is -80V, the current is 120A; the bias voltage of the TiSi target is -100V, the current is 140A, and the deposition time is 30min; the content of the Ti is controlled to be 16.41 at.%, and the content of the Si is controlled to be 5.70 at.%.

2. The production method according to claim 1, characterized by, In step S1, the bias voltage of the Cr target is -100 V, the current is 60 A, and the deposition time is 10 min.

3. The preparation method according to claim 1, characterized in that The method further comprises a step of cleaning the substrate before step S1.

4. The method of claim 1, wherein, The method further comprises a step of heating the coating chamber to remove contaminants before step S1.

5. The production method according to claim 4, characterized by, The method further comprises a step of etching the surface of the substrate by introducing Ar before step S1.

6. The production method according to claim 5, wherein The coating chamber is heated to 400-500℃ before step S1; The surface of the substrate is etched by introducing Ar under a bias voltage of -400 V for 20 min.

7. A CrAlTiSiN coating, characterized in that, The CrAlTiSiN coating is obtained by the method according to any one of claims 1 to 6.

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