Sand and fatigue resistant integrated coating for strengthening of aluminum alloy surfaces and method of making

Abstract

The present application relates to a coating for surface modification of metal materials, in particular to a sand-proof and fatigue-resistant integrated coating for surface strengthening of aluminum alloy and a preparation method. The technical problem that the existing coating structure for the surface of aluminum alloy cannot simultaneously consider sand-proof and fatigue-resistant performance is solved. The coating comprises a plasma etching layer, a metal ion implantation layer, a Ti metal transition layer and a TiN / Ti nano cycle layer which are sequentially stacked on the surface of the substrate in the thickness direction; the TiN / Ti nano cycle layer comprises n cycle layers; each cycle layer comprises a TiN ceramic layer and a Ti metal layer; in the plurality of cycle layers, the thickness of the Ti metal layer decreases layer by layer in the direction from the substrate to the outer surface of the coating, and the thickness of the TiN ceramic layer increases layer by layer in the direction from the substrate to the outer surface of the coating; the Ti metal transition layer and the TiN / Ti nano cycle layer are prepared by magnetic filter cathode vacuum arc sputtering; Ti ion sputtering layers are interposed in the Ti metal transition layer and the TiN / Ti nano cycle layer; and the preparation method of the coating is also provided.

Description

TECHNICAL FIELD

[0001] The present application relates to a coating for surface modification of metallic materials, in particular to a sand-proof and fatigue-resistant integrated coating for surface strengthening of aluminum alloy and a preparation method thereof. BACKGROUND

[0002] Aluminum alloy turbocharger impeller is an important part of armored vehicle power and the core of the intake system, and its performance and reliability directly determine the performance and environmental adaptability of the engine. However, when sand dust is inhaled into the supercharger and collides with the high-speed rotating impeller, it will cause great erosion damage to the surface of the impeller. With the development of tank engine technology, the second generation of tank engine removes the sand dust filtering device such as felt, which greatly reduces the separation efficiency of sand dust particles, and the size of sand particles entering the engine increases from 70 μm to 200 μm or even higher. The high hardness and high concentration of sand dust inhaled by the engine will seriously damage the shape of the aluminum alloy impeller, leading to the decline of the supercharging effect and the service life of the engine, and affecting the combat performance and durability of armored vehicles. In order to improve the service performance of the turbocharger impeller in the desert environment, prolong its service life and reduce the damage of erosion wear, it is urgent to strengthen the sand-proof and fatigue-resistant surface of the aluminum alloy.

[0003] The nitride coating prepared based on PVD (Physical vapor deposition, PVD) has high hardness and good wear resistance, and is an effective means to improve the sand and dust erosion resistance of aluminum alloy. However, the nitride coating and the aluminum alloy are quite different in thermal conductivity, toughness matching, etc., and the aluminum is easily oxidized, so that there is always a dense oxide film on the surface of the aluminum, which leads to poor interfacial bonding between the aluminum and the nitride coating. Moreover, the difference between the aluminum alloy and the nitride coating in lattice constant inhibits the nucleation process of the nitride on the aluminum alloy substrate, resulting in a low growth rate of the nitride coating and excessive growth stress, so that the nitride coating cannot exhibit ideal wear resistance. The difference in physical properties between the aluminum alloy and the nitride ceramic coating puts higher requirements on the structural design of the coating. In addition to maintaining strong bonding with the substrate, the sand prevention coating must ensure the erosion performance. Under sand and dust erosion, erosion pits will appear on the surface of the coating, which will become a fatigue source on the surface of the high-speed rotating impeller. When the aluminum alloy turbocharger impeller is in service, the impeller rotates at high speed, and due to the difference in elastic modulus and cooperative deformation between the ceramic coating and the aluminum alloy substrate, the pores or cracks on the surface of the coating caused by sand and dust erosion will form a fatigue source, which will have a great influence on the fatigue performance of the substrate. The aluminum impeller of the tank engine has high speed and severe erosion conditions, and the existing coating type and structure cannot realize sand prevention and fatigue resistance. Therefore, it is urgent to design the structure of the protective coating on the surface of the aluminum alloy, develop a sand prevention and fatigue resistance integrated coating suitable for the surface of the aluminum alloy, improve the service life of the aluminum alloy turbocharger impeller, and thus improve the environmental adaptability of the tank engine. SUMMARY

[0004] The purpose of the present application is to solve the technical problem that the existing coating type and structure for the surface of the aluminum alloy cannot simultaneously consider sand prevention and fatigue resistance, and to provide a sand prevention and fatigue resistance integrated coating for surface strengthening of an aluminum alloy and a preparation method.

[0005] The technical scheme of the present application is:

[0006] A sand prevention and fatigue resistance integrated coating for surface strengthening of an aluminum alloy, characterized in that: a plasma etching layer, a metal ion implantation layer, a Ti metal transition layer and a TiN / Ti nano cycle layer are sequentially stacked and laid on the surface of the substrate in the thickness direction.

[0007] The TiN / Ti nano cycle layer comprises n cycle layers stacked along the thickness direction, 2 < n ≤ 20, n is a positive integer, and the thickness of each cycle layer is the same; each cycle layer comprises a TiN ceramic layer and a Ti metal layer stacked on the outer surface of the TiN ceramic layer; in the plurality of cycle layers, the thickness of the Ti metal layer decreases layer by layer along the direction from the substrate to the outer surface of the coating, and the thickness of the TiN ceramic layer increases layer by layer along the direction from the substrate to the outer surface of the coating;

[0008] The Ti metal transition layer and the TiN / Ti nano cycle layer are prepared by magnetic filter cathode vacuum arc sputtering;

[0009] The Ti metal transition layer and the TiN / Ti nano cycle layer both contain a Ti ion sputtering layer; the Ti ion sputtering layer is formed by Ti sputtering once every 10-15 minutes in the process of magnetic filter cathode vacuum arc sputtering;

[0010] The depth of the plasma etching layer is 0.2-5 μm;

[0011] The depth of the metal ion implantation layer is 60-200 nm;

[0012] The thickness of the Ti metal transition layer is 2-5 μm;

[0013] The single-layer thickness of the Ti ion sputtering layer is 10-50 nm;

[0014] The total thickness of a single cycle layer is 0.2-3 μm.

[0015] Further, the depth of the plasma etching layer is 0.5-3 μm; the depth of the metal ion implantation layer is 100-160 nm; the thickness of the Ti metal transition layer is 3-4 μm; the single-layer thickness of the Ti ion sputtering layer 8 is 20-40 nm; and the thickness of a single cycle layer is 1-3 μm.

[0016] Further, the depth of the plasma etching layer is 2 μm; the depth of the metal ion implantation layer is 150 nm; the thickness of the Ti metal transition layer is 4 μm; the single-layer thickness of the Ti ion sputtering layer 8 is 30 nm; and the total thickness of the TiN / Ti nano cycle layer is 12 μm, and the number of cycle layers n is 9.

[0017] Meanwhile, the application also provides a preparation method of the sand prevention and fatigue resistance integrated coating for strengthening the surface of an aluminum alloy, which is characterized by comprising the following steps:

[0018] 1) The surface of the aluminum alloy substrate to be coated is pretreated to keep it dry and clean;

[0019] 2) The substrate surface is subjected to plasma etching at room temperature using plasma etching technology. Then, Ti element is implanted into the plasma-etched substrate surface at room temperature using a metal vacuum vapor ion source implantation method to form a plasma etched layer and a metal ion implantation layer. The depth of the plasma etched layer is 0.2-5 μm, and the depth of the metal ion implantation layer is 60-200 nm.

[0020] 3) A Ti metal transition layer was deposited on the surface of the metal ion implantation layer at room temperature using a magnetically filtered vacuum arc deposition method. The thickness of the Ti metal transition layer was 2–5 μm.

[0021] 4) Combining the magnetic filter vacuum cathode arc deposition method and a compilable flow controller, n alternating TiN ceramic layers and Ti metal layers are prepared on the surface of the Ti metal transition layer at room temperature by controlling the N2 flow rate and Ti metal input amount, where 2 < n ≤ 20 and n is a positive integer, to obtain a TiN / Ti nano-circulation layer, thus completing the preparation of an integrated anti-sand and anti-fatigue coating for strengthening the surface of aluminum alloys.

[0022] The total thickness of a single circulating layer is 0.2–3 μm. During the preparation of a single circulating layer, the N2 flow rate is 40–80 sccm when preparing the TiN ceramic layer and 0 sccm when preparing the Ti metal layer. The thickness of each circulating layer remains the same. Among multiple circulating layers, the thickness of the Ti metal layer decreases layer by layer along the direction from the substrate to the outer surface of the coating, while the thickness of the TiN ceramic layer increases layer by layer along the direction from the substrate to the outer surface of the coating.

[0023] In steps 3) and 4), Ti sputtering is performed every 10 to 15 minutes using a magnetically filtered cathode vacuum arc sputtering method to form a Ti ion sputtering layer;

[0024] The conditions for each sputtering are as follows: N2 flow rate is 0 sccm, arc initiation current is 50-80A, three negative bias sputterings are performed, and the voltages of the three negative bias sputterings are -500V, -300V and -200V in sequence, with a duty cycle of 50%-80%, and each negative bias is maintained for 30-40s.

[0025] Furthermore, in step 2), the plasma etching process is performed under the following conditions: cleaning power of 200–1000 W, frequency of 5–12 MHz, reaction gas of Ar, flow rate of 50–200 sccm, vacuum degree inside the furnace of 0.1–50 Pa, and etching at room temperature for 5–30 min.

[0026] Furthermore, in step 2), the ion implantation conditions are: a vacuum degree of 1.0 × 10⁻⁶. -4 ~1.0×10 -3Pa, normal temperature, the injection voltage is 6-15kV, the beam intensity is 4-10mA, and the total dose of the injected ions is 1.0*10 16 ~1.0*10 17 mC / cm 2 .

[0027] Further, in the step 3), the specific implementation conditions of the magnetic filtering vacuum arc deposition method are as follows: the vacuum degree is 1.0*10 -4 ~1.0*10 -3 Pa, normal temperature, the arc current is 40-60A, the magnetic field current is 1-4A, the negative bias is-50--150V, the duty cycle is 20%-60%, and the beam intensity is 300-400mA.

[0028] Further, in the step 4), the specific implementation conditions of the magnetic filtering vacuum cathode arc deposition method are as follows: the vacuum degree is 1.0*10 -4 ~8.0*10 -3 Pa, normal temperature, the arc current is 50-80A, the magnetic field current is 1-4A, the negative bias is-40--100V, the duty cycle is 20%-60%, and the beam intensity is 300-500mA.

[0029] Further, the step 1) is specifically: the aluminum alloy substrate to be coated is ultrasonically cleaned with anhydrous ethanol and acetone for 2 times, 10 minutes each time, and then quickly dried with high-purity nitrogen.

[0030] Further, in the step 2), the depth of the plasma etching layer is 2um;

[0031] In the step 2), the depth of the metal ion implantation layer is 150nm;

[0032] In the step 3), the thickness of the Ti metal transition layer is 4um;

[0033] In the step 4), when the TiN ceramic layer is prepared, the N2 flow rate is 60sccm; the vacuum degree is 2.0*10 -4 Pa, normal temperature, the arc current is 50A, the magnetic field current is 2.0A, the negative bias is-60V, the duty cycle is 40%, and the beam intensity is 400-500mA; n is 9, and the time length of a single cycle layer is 1200s, wherein the time lengths of the Ti metal layer / TiN ceramic layer in the 9 cycle layers are respectively: 1080s / 120s, 960s / 240s, 840s / 360s, 720s / 480s, 600s / 600s, 480s / 720s, 360s / 840s, 240s / 960s and 120s / 1080s.

[0034] The present application has the following beneficial effects:

[0035] 1. The sand-proof and fatigue-resistant integrated coating for strengthening the surface of an aluminum alloy is a composite gradient coating structure integrating plasma etching structure, ion implantation structure, super-thick metal transition structure and gradient nano-multilayer structure, the thickness and hardness of the coating present gradient variation, and the coating has the characteristics of nanometer structure grain boundary strengthening anti-erosion and multi-interface soft and hard alternating anti-fatigue, thereby realizing the synergistic design of the sand-proof and fatigue-resistant integrated coating for the surface of an aluminum alloy. The coating structure greatly enhances the adhesion between the aluminum alloy substrate and the film layer through the plasma etching+ion implantation layer structure, forms high film-substrate adhesion, the super-thick metal transition structure can significantly reduce the energy of fatigue cracks reaching the surface of the substrate and reduce the possibility of fatigue cracking of the ductile aluminum alloy substrate, the TiN / Ti nano-circulating layer, the thickness of the metal Ti layer is gradually reduced with the increase of the number of circulating layer stacking, the thickness of the TiN ceramic layer is gradually increased with the increase of the number of circulating layer stacking, and the total thickness of each single circulating layer (metal Ti layer+TiN ceramic layer) is unchanged. The structure combines the super-hard characteristics of the nano-multilayer structure, and the addition of the gradient structure also solves the stress concentration problem caused by the great difference in material properties on both sides of the interface in the multilayer structure, so the fatigue resistance is also good, and the structure is particularly suitable for being deposited on the aluminum alloy supercharger impeller of the power system of armored vehicles, tanks and other military vehicles to resist the high-speed erosion of sand and dust particles and improve the environmental adaptability of the tank engine, and has great application value.

[0036] 2. The sand-proof and fatigue-resistant integrated coating for strengthening the surface of an aluminum alloy, the depth of the plasma etching layer is 0.2-5 μm; the depth of the metal ion implantation layer is 60-200 nm; the thickness of the Ti metal transition layer is 2-5 μm, and the depth of the plasma etching layer is less than 0.2 μm, which will not completely remove the oxidation layer, and more than 5 μm will increase the surface roughness too much; the depth of the metal ion implantation layer is 60-200 nm, which is suitable for small ion implantation equipment to strengthen the adhesion; the thickness of the Ti metal transition layer is 2-5 μm, which is a particularly thick transition layer, can reduce the energy of fatigue cracks reaching the surface of the substrate and reduce the possibility of fatigue cracking of the ductile aluminum alloy substrate; the coating thickness design of the present application can significantly improve the sand and dust erosion resistance.

[0037] 3. The preparation method of the sand-proof and fatigue-resistant integrated coating for strengthening the surface of aluminum alloy, which combines plasma etching, metal vacuum vapor ion source injection, magnetic filtering vacuum cathode arc deposition, magnetic filtering vacuum cathode arc sputtering and programmable flow controller technology. The plasma etching method is used to clean the surface of the substrate and remove the oxide layer, laying a foundation for strengthening the film-substrate adhesion; the metal vacuum vapor ion source injection method is used to perform ion injection on the surface of the substrate after plasma etching; in the ion injection technology, the energy-carrying ions are injected into the subsurface of the substrate, so that a strong bonding layer of mixed metal-substrate atoms is formed in the subsurface without an interface, which can effectively connect the substrate and the coating together to obtain super-high film-substrate adhesion; on the metal ion injection layer, the magnetic filtering vacuum cathode arc deposition method is used to deposit a Ti metal transition layer, and then deposit a TiN / Ti nanometer multi-layer cycle layer by controlling the input N2 flow; in the cycle layer, the thickness gradient of the Ti metal layer decreases, and the thickness gradient of the TiN ceramic layer increases; during the magnetic filtering vacuum cathode arc deposition process, Ti ion sputtering is performed once every 10-15 minutes in a high bias mode. The plasma etching removes the oxide layer on the surface of the aluminum substrate, and then the metal ion injection layer and the Ti metal transition layer are prepared to form a strong film-substrate adhesion. In the TiN / Ti nanometer cycle layer, the multi-layer coating with alternating ceramic / metal layers has a better anti-erosion performance than the single-layer nitride coating due to the interface effect, and the multi-layer coating fails in the form of layer-by-layer peeling when subjected to sand and dust erosion; the large number of grain boundaries in the nanometer-scale coating effectively increases the resistance to crack propagation caused by erosion, and the anti-erosion performance is significantly improved; and the presence of the magnetic filtering bend pipe can filter out almost all neutral particles, droplets and large particles, which is beneficial to improve the compactness, purity and surface roughness of the coating. After the brittle nitride coating surface initiates a crack, the crack will quickly expand to the inside of the substrate, and the high-thickness and high-toughness metal transition layer close to the substrate will significantly reduce the energy of the fatigue crack reaching the surface of the substrate, and reduce the possibility of fatigue cracking of the tough aluminum alloy substrate.

[0038] 4. The preparation method of the sand-proof and fatigue-resistant integrated coating for strengthening the surface of aluminum alloy, which adopts plasma etching, metal ion injection technology and gradient nanotechnology structure to solve the problem of poor matching performance of the anti-erosion coating and the aluminum alloy substrate; adopts the magnetic filtering vacuum cathode arc deposition technology to solve the coating defect problem; adopts the Ti metal transition layer and the TiN / Ti nanometer cycle layer structure to form a smooth transition between the soft and hard layers, so as to maintain the anti-erosion performance and achieve high strength and toughness matching without reducing the fatigue life. The coating structure design of the present application is suitable for sand-proof and fatigue-resistant integrated protection of the surface of aluminum alloy, solves the core problem of weak service ability of aluminum alloy impeller in sand and dust environment, improves the service life of the aluminum alloy supercharger impeller, and further improves the environmental adaptability of the tank engine.

[0039] 5、The application is a preparation method of sand-proof and fatigue-resistant integrated coating for surface strengthening of aluminum alloy, which is suitable for more low-melting-point base materials under the premise of ensuring the performance of the coating. The room-temperature preparation ability of high-performance coating is realized through ion etching, ion implantation and magnetic filtering vacuum cathode arc composite technology; and the high-performance coating is prepared under the condition of low ion bombardment temperature by combining low arc current, low bias voltage, low duty cycle process parameter selection and high-frequency high-bias magnetic filtering cathode vacuum arc sputtering composite process. Compared with the traditional PVD deposition methods such as magnetron sputtering and ion plating, the preparation method proposed in the application does not need auxiliary heating and can be used for coating preparation at room temperature, and the temperature after plasma bombardment is effectively controlled within 30-140 DEG C, which greatly expands the selection range of the traditional PVD coating preparation process and has great application value. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a structural schematic diagram of an embodiment of the sand-proof and fatigue-resistant integrated coating for surface strengthening of aluminum alloy.

[0041] The drawing mark is: 1-base, 2-plasma etching layer, 3-metal ion implantation layer, 4-Ti metal transition layer, 5-TiN / Ti nanometer cycle layer, 6-TiN ceramic layer, 7-Ti metal layer, 8-Ti ion sputtering layer. DETAILED DESCRIPTION

[0042] The application will be described in detail below through embodiments and drawings.

[0043] The application provides a sand-proof and fatigue-resistant integrated coating for surface strengthening of aluminum alloy, as shown in the figure, which comprises a plasma etching layer 2, a metal ion implantation layer 3, a Ti metal transition layer 4 and a TiN / Ti nanometer cycle layer 5 which are sequentially stacked and laid on the surface of a base 1 in the thickness direction. Figure 1 The TiN / Ti nanometer cycle layer 5 comprises n cycle layers which are stacked and laid in the thickness direction, 2

[0044] The Ti metal transition layer 4 and the TiN / Ti nano cycle layer 5 are prepared by magnetic filter cathode vacuum arc sputtering. The Ti ion sputtering layer 8 is formed by sputtering Ti once every 10-15 minutes during the magnetic filter cathode vacuum arc sputtering process. The thickness of each layer in the coating is as follows: the depth of the plasma etching layer 2 is 0.2-5 μm, preferably 0.5-3 μm; the depth of the metal ion implantation layer 3 is 60-200 nm, preferably 100-160 nm; the thickness of the Ti metal transition layer 4 is 2-5 μm, preferably 3-4 μm; the thickness of a single layer of the Ti ion sputtering layer 8 is 10-50 nm, preferably 20-40 nm; the thickness of a single cycle layer is 0.2-3 μm, preferably 1-3 μm; the thickness of the TiN ceramic layer 6 in the cycle layer closest to the Ti metal transition layer 4 is 0.02-0.2 μm, and the thickness of the Ti metal layer 7 is 0.2-3 μm. In this embodiment, the substrate 1 is an aluminum alloy substrate, the depth of the plasma etching layer 2 is 2 μm, the depth of the metal ion implantation layer 3 is 150 nm, the thickness of the Ti metal transition layer 4 is 4 μm, the thickness of a single layer of the Ti ion sputtering layer 8 is 30 nm, the total thickness of the TiN / Ti nano cycle layer 5 is 12 μm, and the number of cycle layers n is 9. The coating preparation process of the present application is carried out at room temperature, and the temperature after ion bombardment is not higher than 140°C.

[0045] The sand and fatigue resistant integrated coating for strengthening the surface of aluminum alloy is composed of a plasma etching layer 2, a metal ion implantation layer 3, a Ti metal transition layer 4, and a TiN / Ti nanometer cycle layer 5 (wherein the thickness gradient of the Ti metal layer is reduced and the thickness gradient of the TiN ceramic layer is increased). The plasma etching is a process of cleaning or removing material from the surface of a substrate using plasma technology. The surface oxide layer of the aluminum substrate can be effectively and controllably removed by plasma etching. The metal ion implantation layer 3 is implanted into the subsurface of the substrate 1 by means of a charged ion, so that the subsurface of the substrate 1 and the implanted ion form a metal-substrate atom mixed layer without an interface, thereby forming a strengthened bonding layer and laying a foundation for the deposition of the upper film layer and forming a strong film-substrate bonding force. In the TiN / Ti nanometer cycle layer 5, the multi-layer coating of ceramic / metal alternately, due to the interface effect, when subjected to sand and dust erosion, is more likely to fail in the form of layer-by-layer peeling, and therefore its anti-erosion performance is far superior to that of a single-layer nitride coating. A large number of grain boundaries in the nanometer-scale coating effectively increase the resistance to the expansion of cracks caused by erosion, and the anti-erosion performance is significantly improved. After the brittle nitride coating layer initiates a crack, the crack will quickly expand to the inside of the substrate, and the high-thickness and ductile metal layer close to the substrate 1 will significantly reduce the energy of the fatigue crack reaching the surface of the substrate, thereby reducing the possibility of fatigue cracking of the ductile aluminum alloy substrate. The TiN / Ti nanometer cycle layer 5 combines the characteristics of multi-layer coating anti-erosion, nanometer structure multi-interface, and gradient distribution strong bonding, and can achieve the goal of anti-erosion and fatigue resistance.

[0046] The application also provides a preparation method of the sand and fatigue resistant integrated coating for strengthening the surface of aluminum alloy.

[0047] Example 1

[0048] 1) Cleaning of the substrate

[0049] The aluminum alloy substrate to be coated is cleaned with anhydrous ethanol and acetone for 2 times, 10 minutes each time, and then quickly dried with high-purity nitrogen.

[0050] 2) The surface of the aluminum alloy substrate is treated by plasma etching at room temperature (i.e. cleaning and removing oxidation), and then the surface of the aluminum alloy substrate after the plasma etching treatment is pre-implanted with Ti elements at room temperature by means of a metal vacuum vapor ion source (MEVVA) implantation method (i.e. forming a bonding layer), thereby forming the plasma etching layer 2 and the metal ion implantation layer 3. The depth of the plasma etching layer 2 is about 2 μm, and the depth in other examples can be 0.2-5 μm. The depth of the metal ion implantation layer 3 is 150 nm, and the depth in other examples can be 60-200 nm.

[0051] In this embodiment, the plasma etching treatment is performed under the following conditions: cleaning power of 1000 W, frequency of 10 MHz, reaction gas of Ar, flow rate of 100 sccm, vacuum degree in the furnace of 2 Pa, etching at room temperature for 20 min, and ion bombardment temperature of 30°C after heating. In other embodiments, the plasma etching treatment can be performed under the following conditions: cleaning power of 200-1000 W, frequency of 5-12 MHz, reaction gas of Ar, flow rate of 50-200 sccm, vacuum degree in the furnace of 0.1-50 Pa, etching at room temperature for 5-30 min. The ion bombardment temperature reaches 30-50°C after heating during the plasma etching.

[0052] The ion implantation is performed under the following conditions: vacuum degree of 3 x 10 -4 Pa, room temperature, implantation voltage of 12 kV, beam current of 5 mA, total ion dose of 6 x 10 16 mC / cm 2 , and ion bombardment temperature of 30°C after heating. In other embodiments, the ion implantation can be performed under the following conditions: vacuum degree of 1.0 x 10 -4 -1.0 x 10 -3 Pa, room temperature, implantation voltage of 6-15 kV, beam current of 4-10 mA, total ion dose of 1.0 x 10 16 -1.0 x 10 17 mC / cm 2 . The ion bombardment temperature reaches 30-40°C after heating during implantation.

[0053] 3) Ti metal transition layer 4 is deposited on the surface of the metal ion implantation layer 3 at room temperature by a magnetic filtered vacuum arc deposition method. The thickness of the Ti metal transition layer 4 is 4 μm, and in other embodiments, the thickness is 2-5 μm.

[0054] In this embodiment, the transition layer deposition is performed under the following conditions: vacuum degree of 8.0 x 10 -4 Pa, arc current of 50 A, magnetic field current of 2.0 A, negative bias of -60 V, duty cycle of 40%, beam current of 400 mA, no heating, and ion bombardment temperature of 80°C after heating.

[0055] In other embodiments, the transition layer deposition can be performed under the following conditions: vacuum degree of 1.0 x 10 -4 -1.0 x 10 -3 Pa, room temperature, arc current of 40-60 A, magnetic field current of 1-4 A, negative bias of -50 to -150 V, duty cycle of 20%-60%, and beam current of 300-400 mA. The ion bombardment temperature reaches 40-100°C after heating during deposition.

[0056] 4) In step 5), the TiN / Ti nanometer cycle layer 5 is prepared by controlling the N2 flow and the Ti metal input on the surface of the Ti metal transition layer 4 at room temperature, and the anti-sand and fatigue integrated coating for the surface strengthening of the aluminum alloy is prepared. In other embodiments, the cycle layer is n, 2 < n < 20, and n is a positive integer. The total thickness of a single cycle layer is 0.2-3 μm. In the preparation of a single cycle layer, the N2 flow is 40-80 sccm when the TiN ceramic layer 6 is prepared, and the N2 flow is 0 sccm when the Ti metal layer 7 is prepared. The thickness of each cycle layer is the same. In the multiple cycle layers, the thickness of the Ti metal layer 7 decreases layer by layer from the substrate 1 to the outer surface of the coating, and the thickness of the TiN ceramic layer 6 increases layer by layer from the substrate 1 to the outer surface of the coating. The outermost cycle layer is a thin metal Ti + thick ceramic TiN layer.

[0057] In step 5) of the embodiment, the vacuum degree is 2.0 x 10 -4 - 3.0 x 10 -3 Pa, no heating, the arc current is 50 A, the magnetic field current is 2.0 A, the negative bias is -60 V, the duty cycle is 40%, the beam intensity is 400-500 mA, and the duration of a single cycle layer is 1200 s. The duration of the Ti metal layer (N2 flow is 0 sccm) / TiN ceramic layer (N2 flow is 60 sccm) of each cycle layer is 1080 s / 120 s, 960 s / 240 s, 840 s / 360 s, 720 s / 480 s, 600 s / 600 s, 480 s / 720 s, 360 s / 840 s, 240 s / 960 s, 120 s / 1080 s, respectively. The temperature after ion bombardment reaches 100-140℃, the total deposition time of the TiN / Ti nanometer cycle layer 5 is 180 min, and the total layer thickness is 12 μm.

[0058] In step 5) of other embodiments, the vacuum degree can be 1.0 x 10 -4 - 8.0 x 10 -3 Pa, room temperature, the arc current is 50-80 A, the magnetic field current is 1-4 A, the negative bias is -40 to -100 V, the duty cycle is 20%-60%, the beam intensity is 300-500 mA, and the temperature after ion bombardment during deposition is 60-140℃.

[0059] 6) In steps 4) and 5), Ti sputtering is performed every 12 minutes by the method of magnetic filter cathode vacuum arc sputtering to form a Ti ion sputtering layer 8. In other embodiments, Ti sputtering can be performed every 10-15 minutes, and the single layer thickness of the Ti ion sputtering layer 8 is 10-50 nm. The conditions for each sputtering are as follows: the vacuum degree is 2.0 x 10-4 Pa, N2 flow rate is 0 sccm, arc current is 50-80 A, arc current in this embodiment is 50 A, magnetic field current is 3.0 A, negative bias is -40 V, three times of negative bias sputtering is performed, the voltage of three times of negative bias sputtering is -500 V, -300 V and -200 V in turn, duty cycle is 50%-80%, duty cycle in this embodiment is 80%, and each negative bias is maintained for 30 s, and other embodiments can also be maintained for 30-40 s.

[0060] Example 2

[0061] Example 2 is prepared by using the same method as that of Example 1, and the difference between Example 2 and Example 1 is that the plasma etching treatment time is 2 min, and the depth of the plasma etching layer 2 is 0.2 μm.

[0062] The metal ion implantation layer 3 is prepared by using an implantation voltage of 8 KV and a total ion dose of 2×1016 mC / cm2, and the depth of the metal ion implantation layer 3 is 60 nm. 16 2 The Ti metal transition layer 4 has a deposited layer thickness of 2 μm, the TiN / Ti nanometer cycle layer 5 has a deposited cycle number of 12, and the total thickness of the TiN / Ti nanometer cycle layer 5 is 6 μm.

[0063] Example 3

[0064] Example 3 is prepared by using the same method as that of Example 1, and the difference between Example 3 and Example 1 is that the plasma etching treatment time is 50 min, and the depth of the plasma etching layer 2 is 5 μm. 17 2 The metal ion implantation layer 3 is prepared by using an implantation voltage of 15 KV and a total ion dose of 1×1017 mC / cm2, and the depth of the metal ion implantation layer 3 is 200 nm.The Ti metal transition layer 4 has a deposited layer thickness of 5 μm, the TiN / Ti nanometer cycle layer 5 has a deposited cycle number of 15, and the total thickness of the TiN / Ti nanometer cycle layer 5 is 20 μm.

[0065] Example 4

[0066] The difference between Example 4 and Example 1 is that the Ti metal transition layer has a deposited layer thickness of 2 μm, and the gradient TiN / Ti nanometer multilayer has a deposited cycle number of 9 and a total cycle thickness of 18 μm.

[0067] Example 5

[0068] Example 5 is prepared by using the same method as that of Example 1, and the difference between Example 5 and Example 1 is that the Ti metal transition layer 4 has a deposited layer thickness of 2 μm, and the TiN / Ti nanometer cycle layer 5 has a deposited cycle number of 3 and a total cycle thickness of 6 μm.​

[0069] Example 6

[0070] Example 6 uses the same method as example 1 to prepare the coating, the difference between example 6 and example 1 is that the deposition layer thickness of Ti metal transition layer 4 is 5 μm; the deposition cycle number of TiN / Ti nano cycle layer 5 is 18, and the total thickness of the cycle layer is 18 μm.

[0071] Example 7

[0072] Example 7 uses the same method as example 1 to prepare the coating, the difference between example 7 and example 1 is that the deposition layer thickness of Ti metal transition layer 4 is 5 μm; the deposition cycle number of TiN / Ti nano cycle layer 5 is 3, and the total thickness of the cycle layer is 6 μm.

[0073] It should be noted that, in order to simply describe, the above examples are described as a combination of a series of steps according to the specific embodiments, but it cannot be determined that the specific embodiments of the present application are limited to this. Within the spirit and principles of the present application, those skilled in the art can make various modifications and improvements on the basis of the above examples, and these modifications and improvements fall within the protection scope of the present application. Those skilled in the art should understand that the examples described in the specification are all preferred examples, and the actions involved are not necessarily essential to the present application, and in the case of no conflict, the embodiments of the present application and the features in the examples can be combined with each other. In addition, the base material selected in the present embodiment is 2A70 aluminum alloy used for processing aluminum alloy supercharger impeller of power system of tank and other military vehicles, but the base material in the present embodiment is not limited to 2A70 aluminum alloy base material, but also can be other aluminum alloy, composite material, titanium alloy, steel and high temperature alloy and other commonly used materials of power system impeller. The coating is mainly designed and prepared for the low preparation temperature sandproof and fatigue-resistant integrated coating on the surface of low melting point high-speed moving impeller material, which can be applied to other moving parts materials with melting point higher than aluminum alloy.

Claims

1. An integrated anti-sand and anti-fatigue coating for strengthening the surface of aluminum alloys, characterized in that: It includes a plasma etching layer (2), a metal ion implantation layer (3), a Ti metal transition layer (4) and a TiN / Ti nano-circulation layer (5) that are sequentially stacked on the surface of the substrate (1) along the thickness direction. The TiN / Ti nano-circulating layer (5) includes n circulating layers stacked along the thickness direction, where 2 < n ≤ 20, and n is a positive integer. The thickness of each circulating layer is the same. Each circulating layer includes a TiN ceramic layer (6) and a Ti metal layer (7) stacked on the outer surface of the TiN ceramic layer (6). Among the multiple circulating layers, the thickness of the Ti metal layer (7) decreases layer by layer along the direction from the substrate (1) to the outer surface of the coating, and the thickness of the TiN ceramic layer (6) increases layer by layer along the direction from the substrate (1) to the outer surface of the coating. The Ti metal transition layer (4) and the TiN / Ti nano-circulation layer (5) were both prepared by magnetically filtered cathode vacuum arc sputtering; Both the Ti metal transition layer (4) and the TiN / Ti nano-circulation layer (5) contain Ti ion sputtering layers (8); the Ti ion sputtering layer (8) is formed by sputtering Ti every 10 to 15 minutes during the magnetic filter cathode vacuum arc sputtering process; the conditions for each sputtering are: N2 flow rate of 0 sccm, arc current of 50 to 80 A, three negative bias sputterings, the voltages of the three negative bias sputterings are -500V, -300V and -200V in sequence, the duty cycle is 50% to 80%, and each negative bias is maintained for 30 to 40 seconds; The depth of the plasma etching layer (2) is 0.2–5 μm; The depth of the metal ion implantation layer (3) is 60-200 nm; The thickness of the Ti metal transition layer (4) is 2-5 μm; The thickness of the Ti ion sputtering layer (8) is 10~50nm; The total thickness of a single circulating layer is 0.2~3μm.

2. The anti-sand and fatigue-resistant integrated coating for strengthening aluminum alloy surfaces according to claim 1, characterized in that: The depth of the plasma etching layer (2) is 0.5 to 3 μm; The depth of the metal ion implantation layer (3) is 100-160 nm; The thickness of the Ti metal transition layer (4) is 3-4 μm; The thickness of the Ti ion sputtering layer (8) is 20~40nm; The thickness of a single cyclic layer is 1~3μm.

3. The integrated anti-sand and anti-fatigue coating for strengthening aluminum alloy surfaces according to claim 2, characterized in that: The plasma etching layer (2) has a depth of 2 μm; The depth of the metal ion implantation layer (3) is 150 nm; The thickness of the Ti metal transition layer (4) is 4 μm; The thickness of the Ti ion sputtering layer (8) is 30 nm. The total thickness of the TiN / Ti nano-circulating layer (5) is 12 μm, and the number of circulating layers n is 9.

4. A method for preparing an integrated anti-sand and anti-fatigue coating for strengthening the surface of aluminum alloys as described in any one of claims 1-3, characterized in that, Includes the following steps: 1) Pre-treat the surface of the aluminum alloy substrate (1) to be coated to keep it dry and clean; 2) Plasma etching technology is used to perform plasma etching treatment on the surface of the substrate (1) at room temperature. Then, Ti element is implanted into the surface of the plasma-etched substrate (1) at room temperature using a metal vacuum vapor ion source implantation method to form a plasma etching layer (2) and a metal ion implantation layer (3). The depth of the plasma etching layer (2) is 0.2-5 μm, and the depth of the metal ion implantation layer (3) is 60-200 nm. 3) A Ti metal transition layer (4) is deposited on the surface of the metal ion implantation layer (3) at room temperature using a magnetic filter vacuum arc deposition method. The thickness of the Ti metal transition layer (4) is 2-5 μm. 4) Combining the magnetic filter vacuum cathode arc deposition method and a compilable flow controller, n alternating TiN ceramic layers (6) and Ti metal layers (7) are prepared on the surface of the Ti metal transition layer (4) at room temperature by controlling the N2 flow rate and Ti metal input amount, where 2 < n ≤ 20 and n is a positive integer, to obtain the TiN / Ti nano-circulation layer (5), thus completing the preparation of an integrated anti-sand and anti-fatigue coating for strengthening the surface of aluminum alloy; The total thickness of a single circulating layer is 0.2~3μm; during the preparation of a single circulating layer, when preparing the TiN ceramic layer (6), the N2 flow rate is 40~80sccm, and when preparing the Ti metal layer (7), the N2 flow rate is 0sccm; the thickness of each circulating layer is kept the same, and among multiple circulating layers, the thickness of the Ti metal layer (7) decreases layer by layer along the direction from the substrate (1) to the outer surface of the coating, and the thickness of the TiN ceramic layer (6) increases layer by layer along the direction from the substrate (1) to the outer surface of the coating; In steps 3) and 4), Ti sputtering is performed every 10 to 15 minutes using magnetically filtered cathode vacuum arc sputtering to form a Ti ion sputtering layer (8). The conditions for each sputtering are as follows: N2 flow rate is 0 sccm, arc initiation current is 50-80A, three negative bias sputterings are performed, and the voltages of the three negative bias sputterings are -500V, -300V and -200V in sequence, with a duty cycle of 50%-80%, and each negative bias is maintained for 30-40s.

5. The method for preparing the integrated anti-sand and anti-fatigue coating for strengthening aluminum alloy surfaces according to claim 4, characterized in that, In step 2), the plasma etching process is performed under the following conditions: cleaning power of 200–1000 W, frequency of 5–12 MHz, reaction gas of Ar, flow rate of 50–200 sccm, vacuum degree inside the furnace of 0.1–50 Pa, and etching at room temperature for 5–30 min.

6. The method for preparing an integrated anti-sand and anti-fatigue coating for strengthening aluminum alloy surfaces according to claim 5, characterized in that, In step 2), the ion implantation is performed under the following conditions: vacuum degree 1.0 x 10 -4 Pa, normal temperature, implantation voltage 6-15 kV, beam intensity 4-10 mA, and total dose of implanted ions 1.0 x 10 -3 mC / cm 16 . 17 mC / cm 2 .

7. The method for preparing an integrated anti-sand and anti-fatigue coating for strengthening aluminum alloy surfaces according to claim 6, characterized in that, In step 3), the specific implementation conditions of the magnetic filter vacuum arc deposition method are: vacuum degree 1.0 x 10 -4 ~ 1.0 x 10 -3 Pa, normal temperature, arc current 40-60 A, magnetic field current 1-4 A, negative bias -50--150 V, duty cycle 20%-60%, and beam intensity 300-400 mA.

8. The method for preparing an integrated anti-sand and anti-fatigue coating for strengthening aluminum alloy surfaces according to claim 7, characterized in that, In step 4), the specific implementation conditions of the magnetic filter vacuum cathodic arc deposition method are as follows: vacuum degree is 1.0×10 -4 ~8.0×10 -3 Pa, normal temperature, arc current is 50-80 A, magnetic field current is 1-4 A, negative bias is -40--100 V, duty cycle is 20%-60%, and beam current intensity is 300-500 mA.

9. The method for preparing an integrated anti-sand and anti-fatigue coating for strengthening aluminum alloy surfaces according to claim 8, characterized in that, Step 1) Specifically, the aluminum alloy substrate (1) to be coated is ultrasonically cleaned twice with anhydrous ethanol and acetone for 10 minutes each time, and then quickly dried with high-purity nitrogen.

10. The method for preparing an integrated anti-sand and anti-fatigue coating for strengthening aluminum alloy surfaces according to claim 9, characterized in that: In step 2), the depth of the plasma etching layer (2) is 2 μm; In step 2), the depth of the metal ion implantation layer (3) is 150 nm; In step 3), the thickness of the Ti metal transition layer (4) is 4 μm; In step 4), when preparing the TiN ceramic layer (6), the N2 flow rate is 60 sccm; the vacuum degree is 2.0 × 10⁻⁶. -4 Pa, room temperature, arc current of 50A, magnetic field current of 2.0A, negative bias of -60V, duty cycle of 40%, beam intensity of 400~500mA; n is 9, the duration of a single cycle layer is 1200s, among which, the durations of Ti metal layer (7) / TiN ceramic layer (6) in the 9 cycle layers are: 1080s / 120s, 960s / 240s, 840s / 360s, 720s / 480s, 600s / 600s, 480s / 720s, 360s / 840s, 240s / 960s, 120s / 1080s.

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