High-performance aluminum-magnesium alloy nano-composite ion plating process

Abstract

The invention relates to the technical field of coating materials, and discloses a high-performance aluminum-magnesium alloy nano-composite ion plating process which comprises the following components in atomic percent: 82-88% of aluminum; 12%-18% of magnesium; 0.3%-0.7% of carbon; 1.2%-2.5% of nitrogen; the atomic ratio of the yttrium to the titanium is 0.15 to 0.25; the microstructure of the coating is a composite structure of isometric crystals of 5-8 nm and amorphous phases of 2-5 nm. A micro-arc oxidation pretreatment layer is arranged at the interface of the coating and the substrate, the thickness of the pretreatment layer is 5-8 [mu] m, the aperture is 200-500 nm, the porosity is 15%-25%, yttrium exists in a core-shell structure form that TiB2 is coated with Y2O3, the thickness of a Y2O3 coating layer is 2-5 [mu] m, and the Y2O3 coating layer accounts for 5%-8% of the total mass of the composite target material. Through aluminum-magnesium matrix component optimization and core-shell strengthening phase design, the obdurability and component stability of the coating are synergistically improved, and meanwhile, the asymmetric plasma regulation and control and gradient deposition processes are innovatively combined, so that the deposition uniformity and the structure controllability are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of coating materials, in particular to a high-performance aluminum-magnesium alloy nanocomposite ion plating process. Background Art

[0002] As a key branch of surface engineering, aluminum-magnesium alloy nanocomposite coating technology holds great promise for application in high-end equipment applications such as aerospace and automotive manufacturing. Current mainstream technologies utilize magnetron sputtering or multi-arc ion plating processes to enhance coating hardness by introducing a hard ceramic phase.

[0003] However, existing technology systems have gradually exposed common bottlenecks in engineering applications: magnesium is prone to selective volatilization during high-temperature deposition, causing the coating composition to deviate from the designed value and affecting service stability; traditional process parameter control models are difficult to reconcile the contradiction between deposition rate and coating density, and columnar crystals and interface pores are easily generated during high-speed deposition, becoming sources of stress concentration; the thermal expansion coefficient mismatch between the coating and the lightweight alloy substrate has long existed, which can easily lead to interface delamination failure under thermal cycling conditions. Although researchers have attempted to improve the coating through transition layer design or process optimization in recent years, a single approach often loses focus and cannot achieve the coordinated optimization of coating composition, structure, and performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-performance aluminum-magnesium alloy nanocomposite ion plating process, which solves the problems of high-temperature volatilization of magnesium elements in aluminum-magnesium alloy coatings, uneven distribution of nanophases and insufficient interface bonding strength in the prior art.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A high-performance aluminum-magnesium alloy nanocomposite ion plating process, comprising the following components in atomic percentage: Aluminum: 82%-88%; Magnesium: 12%-18%; Carbon: 0.3%-0.7%; Nitrogen: 1.2%-2.5%; Yttrium and titanium: the balance, and the atomic ratio of yttrium to titanium is 0.15-0.25; The microstructure of the coating is a composite structure of 5-8 nm equiaxed crystals and 2-5 nm amorphous phases.

[0006] Preferably, a micro-arc oxidation pretreatment layer is provided at the interface between the coating and the substrate, the pretreatment layer has a thickness of 5-8 μm, a pore size of 200-500 nm, and a porosity of 15%-25%.

[0007] Preferably, the yttrium exists in the form of a core-shell structure of Y2O3 coated TiB2, wherein the Y2O3 coating layer has a thickness of 2-5 μm and accounts for 5%-8% of the total mass of the composite target.

[0008] A high-performance aluminum-magnesium alloy nanocomposite ion plating process comprises the following steps: (1) Micro-arc oxidation pretreatment of substrate surface; (2) Installing the aluminum-magnesium alloy main target and the Y2O3@TiB2 composite auxiliary target; (3) Constructing an asymmetric plasma environment; (4) Gradient deposition was implemented in three stages; (5) Post-processing optimizes coating performance.

[0009] Preferably, the electrolyte for the micro-arc oxidation pretreatment in (1) comprises: Sodium silicate: 0.04-0.06 mol / L Potassium fluoride: 0.02-0.04 mol / L; The processing voltage is 320-380V DC and the processing time is 6-10 minutes.

[0010] Preferably, the asymmetric plasma environment in (3) is constructed by the following method: The main target uses a Halbach array permanent magnet with a magnetic field strength of 0.45-0.55T; The auxiliary target is equipped with a dynamic tuning electromagnet with a frequency of 0.8-1.2Hz; Set the three-level plasma confinement ring voltages to +45-55V, -95-105V, and +15-25V respectively.

[0011] Preferably, the three-stage gradient deposition parameters in (4) include: Nucleation stage: pulse frequency 95-105kHz, target spacing 45-55mm, substrate temperature 75-85℃; Transition stage: Dynamically adjust the target distance to d = 50 + 0.08 × (t-30) 2 to 50+0.12×(t-30) 2 Among them, unit: mm, t is time; Stabilization stage: Apply bipolar pulses with positive pulse parameters of +45-55V / 8-12μs and negative pulse parameters of -140-160V / 45-55μs.

[0012] Preferably, the working gas pressure in the transition stage decreases linearly from 0.28-0.32 Pa to 0.08-0.12 Pa, and the process gas flow ratio is argon:nitrogen:acetylene=2.8-3.2:1:0.03-0.07a.

[0013] Preferably, the post-processing in (5) includes: Plasma annealing: 14-16 minutes at an electron temperature of 7.5-8.5 eV and an argon pressure of 1.8-2.2 Pa; Gradient cooling: Cool down to 75-85°C at a rate of 2.5-3.5°C / min. The cooling gas is a mixture of nitrogen and hydrogen with a volume ratio of 3.5:1-4.5:1.

[0014] In summary, the present invention includes at least one of the following beneficial technical effects: 1. This coating combines the synergistic reinforcement of an aluminum-magnesium matrix with trace carbon and nitrogen elements, combined with the nano-pinning effect of a core-shell composite phase, to achieve lightweight properties while maintaining excellent toughness and wear resistance. The unique element ratio design effectively suppresses the high-temperature volatilization of magnesium, ensuring the stability of the coating composition.

[0015] 2. This invention combines a porous transition layer formed by micro-arc oxidation pretreatment with a gradient deposition process to create a dual interface enhancement mechanism of mechanical interlocking and chemical bonding. This multi-scale interface engineering significantly alleviates the thermal stress mismatch between the coating and the substrate, significantly improving spalling resistance.

[0016] 3. This invention utilizes the synergistic effect of an asymmetric plasma environment and dynamic parameter control to overcome the limitations of conventional ion plating processes on deposition uniformity. The three-stage gradient deposition strategy achieves precise control of the coating structure from nanocrystalline to amorphous composite structures through nonlinear changes in timing parameters.

[0017] 4. The rare earth-modified core-shell target design and gradient cooling process combine to ensure the coating maintains a stable microstructure and chemical inertness even at high temperatures. This synergistic thermal-structural stability imparts excellent high-temperature oxidation and thermal shock resistance to the coating, meeting the demands of demanding operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A diagram showing the steps of the method of the present invention. DETAILED DESCRIPTION

[0019] The following is combined with Figure 1 , the present invention is described in further detail.

[0020] The present invention provides a high-performance aluminum-magnesium alloy nanocomposite coating, comprising the following components in atomic percentage: Aluminum: 82%-88%; Magnesium: 12%-18%; Carbon: 0.3%-0.7%; Nitrogen: 1.2%-2.5%; Yttrium and titanium: the balance, and the atomic ratio of yttrium to titanium is 0.15-0.25; The microstructure of the coating is a composite structure of 5-8nm equiaxed crystals and 2-5nm amorphous phases.

[0021] 1. Coating composition and structure 1. Aluminum-magnesium alloy matrix design By limiting the atomic ratio of aluminum (82-88 at%) to magnesium (12-18 at%), the coating's strength is enhanced by the solid solution strengthening effect of magnesium while maintaining lightweight properties. By introducing trace amounts of carbon (0.3-0.7 at%) and nitrogen (1.2-2.5 at%) to form an Al-Mg-CN multi-component system, carbon inhibits dislocation motion through interstitial solid solution, while nitrogen reacts with aluminum and magnesium to form a nano-scale nitride hard phase, achieving a synergistic improvement in strength and toughness.

[0022] 2. Yttrium-titanium composite strengthening mechanism Yttrium (Y) coats TiB2 particles in the form of Y2O3, forming a core-shell structure (Y2O3@TiB2). During the deposition process, the high-temperature stability of Y2O3 inhibits the abnormal growth of TiB2. Yttrium ions also generate a space charge effect in the plasma, constraining the motion of high-energy particles and improving the coating's compositional uniformity. Titanium enhances the coating's corrosion resistance by forming Ti-N bonds. Controlling the Y / Ti atomic ratio within the 0.15-0.25 range ensures a balance between the coating's mechanical properties and its resistance to high-temperature oxidation.

[0023] 2. Interface bonding strengthening Effect of Micro-arc Oxidation Pretreatment Layer A 5-8μm porous layer (pore size 200-500nm) is constructed on the substrate surface. Its mechanism of action is reflected in two aspects: Mechanical interlocking effect: The porous structure provides nanoscale anchoring points for the coating, increasing the interfacial bonding area through physical interlocking; Function of chemical transition layer: The silicate component in the micro-arc oxidation layer reacts with the aluminum-magnesium alloy during the subsequent deposition process to form a gradient diffusion interface, which alleviates the stress concentration caused by the difference in thermal expansion coefficient.

[0024] 3. Plasma environment control Asymmetric magnetic field design The combination of a Halbach permanent magnet array (0.45-0.55T) and a dynamically tuned electromagnet (0.8-1.2Hz) achieves the following control through the spatial asymmetric distribution of the magnetic field gradient: Electron trajectory constraint: Enhances the Lorentz force in the edge area of ​​the magnetic field, extends the electron movement path, and increases the plasma density; Target etching uniformity: The dynamic electromagnetic field causes the target etching area to shift periodically to avoid component segregation caused by local overheating.

[0025] Three-level confinement ring voltage configuration Through the radial voltage gradient of +45-55V / -95-105V / +15-25V, a composite effect of axial electric field and radial magnetic field is formed: Ion focusing effect: the negative high pressure in the middle ring attracts the plasma to gather toward the substrate; Secondary electron suppression: The outer positive voltage captures escaping electrons and reduces substrate temperature fluctuations.

[0026] 4. Dynamic Deposition Control Three-stage gradient deposition strategy Nucleation stage (high-frequency pulse): 95-105kHz high-frequency pulses generate high-density plasma, promoting the uniform nucleation of fine equiaxed crystals (5-8nm); Transition stage (dynamic target distance): d = 50 + 0.08 × (t-30) 2 By adjusting the target distance and changing the collision probability of the particle flight path, a gradual structure change from loose columnar crystals to dense equiaxed crystals can be achieved; Stabilization stage (bipolar pulse): positive pulse (+45-55V) neutralizes the surface charge, and negative pulse (-140-160V) enhances the ion implantation depth to form an amorphous / nanocrystalline composite structure.

[0027] 5. Post-processing optimization Plasma annealing At an electron temperature of 7.5-8.5eV, high-energy electrons bombard the coating surface, triggering the following processes: Defect repair: vacancies migrate to grain boundaries, reducing interfacial stress; Phase structure relaxation: The metastable amorphous phase partially crystallizes to form nano-grains with controllable size (2-5nm).

[0028] Gradient cooling control A slow cooling rate of 2.5-3.5°C / min is used in combination with a N2 / H2 mixed gas to release the interfacial residual stress through the penetration of hydrogen atoms, while suppressing the precipitation of brittle phases during the cooling process.

[0029] Example 1 Step 1: Substrate pretreatment Micro-arc oxidation treatment: Electrolyte: 0.05MNa2SiO3+0.03MKF; Processing parameters: 350 VDC, 8 min, electrolyte temperature 30°C; Ultrasonic cleaning: Acetone / ethanol mixture (1:3 volume ratio), 50 kHz ultrasonic treatment for 18 min; Step 2: Target configuration Main target: Al85Mg15 (at%) alloy target; Auxiliary target: Y2O3@TiB2 (Y2O3 content 6.5wt%); Target activation: helium plasma bombardment (500 eV, 10 min) + gradient annealing (300 °C → 600 °C, 5 °C / min); Step 3: Deposition process Nucleation stage (0-30min): Pulse frequency 100kHz, target distance 50mm; Substrate bias voltage -150 V, gas flow rate Ar / N2 / C2H2=3:1:0.05; Working pressure 0.3Pa, substrate temperature 80℃ Transition phase (30-60 minutes): Dynamic target distance adjustment: d = 50 + 0.1 × (t-30) 2 ; Pulse frequency difference ±2%, dynamic bias -75V; Pressure gradient 0.3→0.1 Pa, substrate temperature 150°C; Stabilization phase (60-120 minutes): Bipolar pulse: +50V / 10μs&-150V / 50μs; Gas feedback control: Q(N2)=0.05√P+0.1T; Working pressure 0.5Pa, substrate temperature 200℃; Step 4: Post-processing Plasma annealing: 8 eV electron temperature, argon pressure 2 Pa, 15 min; Gradient cooling: 3°C / min, N2 / H2=4:1.

[0030] Example 2 Step 1: Substrate pretreatment Micro-arc oxidation treatment: Electrolyte: 0.04MNa2SiO3+0.02MKF; Processing parameters: 320VDC, 6min, electrolyte temperature 25°C; Step 3: Deposition process Nucleation stage: Pulse frequency 95kHz, target distance 45mm; Substrate bias -140 V, gas flow rate Ar / N2 / C2H2 = 2.8:1:0.03; transition stage: Target distance adjustment: d = 50 + 0.08 × (t-30) 2 ; Pulse frequency difference +1.5%, dynamic bias -45V; Stabilization phase: Bipolar pulse: +45V / 8μs&-140V / 45μs; Q(N2)=0.04√P+0.08T; Step 4: Post-processing Plasma annealing: 7.5eV, argon pressure 1.8Pa; Cooling rate 2.5℃ / min, N2 / H2=3.5:1.

[0031] Example 3 Step 1: Substrate pretreatment Micro-arc oxidation treatment: Electrolyte: 0.06MNa2SiO3+0.04MKF; Processing parameters: 380VDC, 10min, electrolyte temperature 35°C; Step 3: Deposition process Nucleation stage: Pulse frequency 105kHz, target distance 55mm; Substrate bias -160 V, gas flow rate Ar / N2 / C2H2=3.2:1:0.07; transition stage: Target distance adjustment: d = 50 + 0.12 × (t-30) 2 ; Pulse frequency difference -2.5%, dynamic bias -105V; Stabilization phase: Bipolar pulse: +55V / 12μs&-160V / 55μs; Q(N2)=0.06√P+0.12T; Step 4: Post-processing Plasma annealing: 8.5eV, argon pressure 2.2Pa; Cooling rate 3.5℃ / min, N2 / H2=4.5:1.

[0032] Comparative Example 1 Compared with Example 1, the difference is: The coating composition does not contain carbon (C) element, and the proportions of the remaining components are adjusted to Al86.3at%, Mg13.5at%, N1.2at%, and Y / Ti atomic ratio of 0.2; The micro-arc oxidation pretreatment step was omitted.

[0033] Comparative Example 2 Compared with Example 1, the difference is: The aluminum-magnesium matrix composition is Al90at%, Mg10at%; Use traditional planar targets (without Y2O3@TiB2 core-shell structure); The magnetic field system uses symmetrical permanent magnets (0.3T).

[0034] Comparative Example 3 Compared with Example 1, the difference is: The deposition process adopts constant temperature (200°C) and constant pressure (0.3Pa) mode, eliminating the three-stage gradient control; The nitrogen flow rate is fixed at Q(N2) = 0.05√P, and the temperature-related term is removed.

[0035] Comparative Example 4 Compared with Example 1, the difference is: Post-treatment was performed with only conventional argon annealing (without plasma assistance); The cooling process adopts natural cooling (no gradient control).

[0036] Comparative Example 5 Compared with Example 1, the difference is: The pulse frequency is unified at 50kHz (no high / low frequency switching); The target distance is fixed at 150mm (no dynamic adjustment); The gas ratio was adjusted to Ar / N2=5:1 (excluding C2H2).

[0037] Test Example 1: Comparative Experimental Description of Coating Mechanical Properties Purpose of the experiment Verify the effects of carbon element doping, composition control and dynamic process synergy on coating hardness, adhesion and elastic modulus.

[0038] Experimental procedures Sample preparation Example 1: Prepared according to the original scheme Comparative Example 1: No carbon element + no micro-arc oxidation Comparative Example 2: Al90at% + traditional target Comparative Example 5: Fixed target distance + single pulse frequency Sample pretreatment All samples were polished to a mirror finish (Ra < 0.02 μm) using diamond suspension. Ultrasonic cleaning with anhydrous ethanol for 10 minutes, followed by drying with nitrogen Vickers hardness test Equipment: Microhardness tester (load 500gf, hold load 15s) For each sample, 5 points were taken with a spacing of 200 μm, and the maximum and minimum values ​​were eliminated to take the average. Scratch adhesion test Equipment: Scratch tester (diamond indenter, tip radius 200 μm) Parameters: scratch rate 10mm / min, load 0-60N linear increase Critical load (Lc) determination: acoustic emission signal mutation + optical microscopy observation Nanoindentation elastic modulus testing Equipment: Nanoindenter (Berkovich indenter) Parameters: Maximum depth 200nm, loading rate 10nm / s Each sample was tested at 10 points and the average value was taken Experimental data Table 1 Mechanical properties comparison test results: The interstitial solid solution of carbon in the aluminum-magnesium matrix and the formation of an amorphous phase effectively inhibit dislocation slip and grain boundary migration. The selective segregation of carbon atoms in the Al-Mg lattice forms a localized distortion field, which, together with the nitride hard phase, constructs a multi-scale strengthening network. This composite strengthening mechanism not only improves hardness but also alleviates stress concentration through the amorphous / nanocrystalline composite structure, resulting in excellent spalling resistance in scratch tests, confirming the key role of trace carbon and nitrogen synergistic doping in mechanical properties.

[0039] The synergistic effect of the core-shell target and plasma confinement. The space charge effect generated by the Y2O3 coating in the plasma environment significantly improves the uniformity of the highly active magnesium element. The ionization energy of yttrium ions (6.38eV) is higher than that of aluminum (5.98eV), forming selective confinement under the action of the magnetic field gradient, inhibiting the abnormal diffusion of magnesium. This target-plasma coupling reduces the distribution fluctuation of magnesium in the coating to 1.1at%, far lower than the 3.8at% of traditional processes, ensuring a balanced improvement in compositional stability and mechanical properties.

[0040] The nonlinear coordinated regulation of dynamic process parameters can match the time and space of high-frequency pulses and close target distance, and the plasma density (>1×10 19 m -3 ) promotes the uniform nucleation of fine equiaxed crystals. As the deposition progresses, dynamic target distance adjustment changes the particle collision free path, and combined with the charge neutralization effect of the bipolar pulse, a gradient structural evolution from dense nanocrystals to amorphous phase is achieved. This nonlinear control strategy of timing parameters increases the coating elastic modulus to 215GPa while controlling the surface defect density to 12 / mm 2level, breaking through the bottleneck of "strength-toughness" trade-off in traditional technology.

[0041] Test Example 2: Corrosion Resistance Comparison Experiment Purpose of the experiment Verify the effects of micro-arc oxidation pretreatment layer and gradient cooling process on the salt spray corrosion resistance and electrochemical properties of the coating.

[0042] Experimental procedures Sample preparation Example 1: Complete process preparation Comparative Example 1: No micro-arc oxidation pretreatment Comparative Example 4: Natural Cooling (No Gradient Control) Salt spray test Equipment: Salt spray chamber (5% NaCl solution, pH 6.5-7.2) Conditions: 35±1℃ continuous spray, sample tilted 15° Observation cycle: Record surface corrosion conditions every 24 hours for 1000 hours Electrochemical testing Electrolytic cell configuration: Working electrode: sample to be tested (exposed area 1cm 2 ) Reference electrode: saturated calomel electrode (SCE) Auxiliary electrode: platinum electrode Electrolyte: 3.5wt% NaCl solution Test process: open circuit potential monitoring (OCP, stable for 30 minutes) Electrochemical impedance spectroscopy (EIS): frequency range 10^5-10^-2Hz, amplitude 10mV Potentiodynamic polarization scan: -0.5V→+1.5V (vsOCP), rate 1mV / s Corrosion product analysis After the salt spray test, the samples were rinsed with deionized water and dried with nitrogen. XRD analysis of surface corrosion product phase composition Experimental data Table 2 Corrosion resistance test results: Interface strengthening mechanism of micro-arc oxidation pretreatment layer The porous oxide layer creates a gradient transition interface between the coating and the substrate through a combination of mechanical interlocking and chemical bonding. The silicate phase generated during micro-arc oxidation reacts in situ with the subsequently deposited aluminum-magnesium alloy, forming a continuous diffusion layer that effectively blocks the penetration path of corrosive media. This interface engineering extends the corrosion initiation time of the coating to 896 hours in salt spray testing, demonstrating the critical role of multi-scale interface design in improving corrosion resistance.

[0043] Stress Control Effect of Gradient Cooling Process The staged cooling strategy controls the lattice distortion rate, promoting the gradient release of residual stress along the thickness direction. The penetration and diffusion of hydrogen atoms during the slow cooling process further passivates the active sites at the grain boundaries, inhibiting the nucleation and propagation of stress corrosion cracks. The dynamic gas ratio (N2 / H2) regulates the surface adsorption energy and reduces the oxygen vacancy concentration in the oxide film, increasing the polarization resistance to 2.1×10 6 Ω·cm 2 level, significantly improving the electrochemical stability.

[0044] Synergistic effect of plasma environment and coating densification The high-density plasma flow under the asymmetric magnetic field confinement enables the deposited particles to obtain higher kinetic energy (>50eV), achieving a dense structure with a coating porosity of less than 0.5%. The selective segregation of the Y2O3 coating phase at the deposition front forms a nanoscale passivation barrier, blocking the Cl - This structure-composition synergistic optimization reduces the corrosion current density by two orders of magnitude, breaking through the service limits of traditional coatings in harsh environments.

[0045] Test Example 3: Process Stability Comparison Experiment Description Purpose of the experiment Verify the influence of gradient deposition parameters and dynamic process on deposition rate, composition uniformity and surface quality.

[0046] Experimental procedures Sample preparation Example 1: Complete Gradient Deposition Process Comparative Example 3: Constant temperature and pressure mode (200°C / 0.3Pa) Comparative Example 5: Fixed target distance (150mm) + single pulse frequency (50kHz) Deposition rate measurement Equipment: Step profiler (scanning length 2mm, step accuracy 0.1nm) Method: Deposition on a silicon wafer mask substrate and measurement of step height difference Take 3 measurements at each sample and calculate the average value Compositional fluctuation analysis Equipment: Field emission electron microscope (EDS surface scanning) Parameters: acceleration voltage 15kV, scanning area 10×10μm Analytical elements: Standard deviation of atomic percentage of Al, Mg, and Y Surface defect statistics Equipment: White light interferometer (50x objective lens) Method: Randomly select 5 200×200μm areas Defect judgment criteria: pits or bumps with a depth of >500nm Experimental data Table 3 Process stability test results: Plasma confinement effect of dynamic parameter synergy The spatiotemporal matching of high-frequency pulses and dynamic target distance optimizes deposition kinetic energy by altering the particle free path distribution. The electromagnetic perturbations generated by the difference-frequency pulses enhance turbulent mixing in the plasma, promoting uniform three-dimensional dispersion of elements such as Y and Ti. This dynamic synergy suppresses compositional fluctuations to within 0.7 at%, surpassing the uniformity limits of traditional fixed-parameter processes and validating the precise control of nanocomposite structures achieved through the gradient deposition strategy.

[0047] Coupling of gas feedback model and phase transition dynamics Based on the dynamic regulation of nitrogen flow rate based on sputtering power and temperature, the metal ionization and reaction gas dissociation rate are balanced in real time. + The stable concentration promotes the in-situ uniform precipitation of AlN nanophases. Combined with the gradient pressure change (0.3→0.1→0.5Pa), a diffusion-reaction competition mechanism is formed, achieving controllable growth of the hard phase size from 5nm to 8nm, eliminating the abnormal coarsening phenomenon of traditional processes.

[0048] Defect self-repair mechanism of bipolar pulses The surface charge neutralization effect generated during the positive pulse phase suppresses the formation of droplet defects caused by micro-arcing discharges. The high-energy ion injection (>50eV) during the negative pulse triggers atomic-level rearrangement, filling the grain boundary micropores through vacancy migration. This dynamic repair process reduces the surface defect density to 12 / mm 2 The new technology combines particle trajectory confinement with asymmetric magnetic field to achieve a synergistic breakthrough in high-speed deposition (2.8μm / h) and low defect rate.

[0049] Test Example 4: High Temperature Performance Comparison Experiment Purpose of the experiment Verify the effects of core-shell target design and gradient cooling process on the high-temperature oxidation resistance and thermal stability of the coating.

[0050] Experimental procedures Sample preparation Example 1: Complete process preparation Comparative Example 2: Al90at% + traditional target Comparative Example 4: Natural Cooling (No Gradient Control) High temperature oxidation test Equipment: Muffle furnace (static air environment) Conditions: 500℃ constant temperature for 100h Measurement method: Sample size: 10×10×2mm, surface polished to Ra<0.1μm Weigh with a precision balance before and after oxidation (accuracy 0.01 mg) Calculation of oxidation weight gain: ΔW / S (unit: mg / cm 2 ) Thermal shock test Equipment: Hot and cold cycle testing machine parameter: High temperature zone: 400℃ for 10 minutes Low temperature zone: room temperature water quenching (25℃ deionized water) Number of cycles: 100 times Failure judgment: edge peeling area> 5% under optical microscope observation High temperature hardness test Equipment: High temperature Vickers hardness tester (vacuum environment) Conditions: 300°C constant temperature, 1kgf load, hold load for 15s Each sample was tested at 5 points with a spacing of ≥ 3 times the indentation diagonal Experimental data Table 4 High temperature performance test results: High-temperature phase stability mechanism of core-shell structures The Y2O3 coating forms a dense oxidation barrier layer at high temperature, and its oxygen ion diffusion coefficient (<10 -16 m 2 The coating's γ / s ratio is significantly lower than that of conventional TiB2 phases, effectively suppressing the formation of oxidation channels within the coating. Yttrium segregation at grain boundaries reduces interfacial energy, hindering the abnormal coarsening of nanocrystals at high temperatures. This allows the coating to maintain an equiaxed crystalline structure of 5-8 nm after oxidation at 500°C, validating the core-shell target design's key contribution to thermal stability.

[0051] Stress relaxation effect of gradient cooling During the staged cooling process, hydrogen atoms preferentially occupy dislocation cores via grain boundary diffusion, suppressing thermal stress-induced microcrack nucleation through pinning. The dynamic matching of cooling rate and thermal expansion coefficient promotes an exponential decay of residual stress along the thickness direction, enabling the coating to maintain an intact interface after 100 thermal shock cycles, thus overcoming the brittle fracture bottleneck of traditional rapid cooling.

[0052] Defect reconstruction mechanism of plasma annealing High-energy electron bombardment triggers structural relaxation in the amorphous phase, driving free-volume defects to migrate to the surface and annihilate them. During annealing, the short-range ordered reconstruction of the Al-Mg-CN system forms a thermodynamically more stable metastable phase, resulting in a coating with a hardness retention rate of 85% at 300°C, significantly superior to the 60% achieved with conventional annealing processes. This demonstrates the technical advantages of energy injection post-treatment.

[0053] Test Example 5: Element Distribution Comparison Experiment Description Purpose of the experiment Verify the effects of micro-arc oxidation pretreatment layer and asymmetric magnetic field on magnesium element retention rate, carbon gradient distribution and Y / Ti atomic ratio stability.

[0054] Experimental procedures Sample preparation Example 1: Complete process preparation Comparative Example 1: No micro-arc oxidation pretreatment Comparative Example 2: Traditional target + symmetrical magnetic field Determination of magnesium content Equipment: Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) Sample processing: Coating stripping (mechanical scraping to avoid substrate contamination) Digestion with nitric acid / hydrofluoric acid mixture (3:1) Dilute to 50 mL with deionized water Carbon element depth distribution analysis Equipment: Glow Discharge Optical Spectrometer (GDOES) parameter: RF power 35W, argon pressure 600Pa Sputtering rate is about 0.3μm / min Analysis depth 0-10μm Y / Ti atomic ratio verification Equipment: X-ray Photoelectron Spectroscopy (XPS) parameter: Analysis area 500×500μm Sputtering time 5min (remove surface contamination layer) Binding energy correction uses the C1s peak (284.8 eV) Experimental data Table 5 Element distribution test results: The porous oxide layer absorbs active metal particles in the initial deposition phase through a capillary effect, forming a gradient concentration field for elemental diffusion. The silicate network in the pretreatment layer selectively adsorbs magnesium ions, effectively inhibiting the surface accumulation and volatilization of magnesium during high-temperature deposition, stabilizing the coating's magnesium content at 14.7 at%, demonstrating the critical role of interface engineering in precise compositional control.

[0055] Plasma confinement effect of core-shell target Y2O3 coating produces localized space charge region during sputtering, and its electric field intensity gradient (>10 5 The high ionization energy of yttrium ions forms an energy screening barrier, enabling the deposition of TiB2 core particles with a more uniform kinetic energy distribution. This allows for a stable Y / Ti atomic ratio of 0.22 at the interface, overcoming the segregation problem of traditional target materials.

[0056] The Halbach array generates a spiral magnetic field line distribution, which separates metal ions of varying mass through the Lorentz force. Aluminum ions (m / z = 27) and magnesium ions (m / z = 24) form differentiated deposition angles under the influence of a magnetic field gradient. Combined with periodic perturbations of a dynamic electromagnetic field, the carbon element gradient coefficient was reduced to 0.92, demonstrating the precise control of the three-dimensional uniform distribution of elements through multi-physics coupling.

[0057] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-performance aluminum-magnesium alloy nanocomposite coating, characterized in that: Includes the following in atomic percentage composition: Aluminum: 82%-88%; Magnesium: 12%-18%; Carbon: 0.3%-0.7%; Nitrogen: 1.2%-2.5%; Yttrium and titanium: the balance, and the atomic ratio of yttrium to titanium is 0.15-0.25; The microstructure of the coating is a composite structure of 5-8 nm equiaxed crystals and 2-5 nm amorphous phases.

2. The high performance aluminum-magnesium alloy nanocomposite coating according to claim 1, characterized in that: A micro-arc oxidation pretreatment layer is provided at the interface between the coating and the substrate. The pretreatment layer has a thickness of 5-8 μm, a pore size of 200-500 nm, and a porosity of 15%-25%.

3. The high performance aluminum-magnesium alloy nanocomposite coating according to claim 1, characterized in that: The yttrium exists in the form of a core-shell structure of Y2O3 coated TiB2, wherein the Y2O3 coating layer has a thickness of 2-5 μm and accounts for 5%-8% of the total mass of the composite target material.

4. A high-performance aluminum-magnesium alloy nanocomposite ion plating process for a high-performance aluminum-magnesium alloy nanocomposite coating according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Micro-arc oxidation pretreatment of substrate surface; (2) Installing the aluminum-magnesium alloy main target and the Y2O3@TiB2 composite auxiliary target; (3) Constructing an asymmetric plasma environment; (4) Gradient deposition was implemented in three stages; (5) Post-processing optimizes coating performance.

5. A high performance aluminum-magnesium alloy nanocomposite ion plating process according to claim 4, characterized in that: The electrolyte for the micro-arc oxidation pretreatment in (1) comprises: Sodium silicate: 0.04-0.06 mol / L Potassium fluoride: 0.02-0.04 mol / L; The processing voltage is 320-380V DC and the processing time is 6-10 minutes.

6. A high performance aluminum-magnesium alloy nanocomposite ion plating process according to claim 4, characterized in that: The asymmetric plasma environment described in (3) is constructed by the following method: The main target uses a Halbach array permanent magnet with a magnetic field strength of 0.45-0.55T; The auxiliary target is equipped with a dynamic tuning electromagnet with a frequency of 0.8-1.2Hz; Set the three-level plasma confinement ring voltages to +45-55V, -95-105V, and +15-25V respectively.

7. The high performance aluminum-magnesium alloy nanocomposite ion plating process according to claim 4, characterized in that: The three-stage gradient deposition parameters described in (4) include: Nucleation stage: pulse frequency 95-105kHz, target spacing 45-55mm, substrate temperature 75-85℃; Transition stage: dynamically adjust the target distance from d = 50 + 0.08 × (t-30)² to 50 + 0.12 × (t-30)², where the unit is mm and t is time; Stabilization stage: Apply bipolar pulses with positive pulse parameters of +45-55V / 8-12μs and negative pulse parameters of -140-160V / 45-55μs.

8. The high performance aluminum-magnesium alloy nanocomposite ion plating process according to claim 7, characterized in that: The working gas pressure in the transition stage is linearly reduced from 0.28-0.32 Pa to 0.08-0.12 Pa, and the process gas flow ratio is argon:nitrogen:acetylene=2.8-3.2:1:0.03-0.07a.

9. The high performance aluminum-magnesium alloy nanocomposite ion plating process according to claim 4, characterized in that: The post-processing in (5) includes: Plasma annealing: 14-16 minutes at an electron temperature of 7.5-8.5 eV and an argon pressure of 1.8-2.2 Pa; Gradient cooling: cool down to 75-85°C at a rate of 2.5-3.5°C / min. The cooling gas is a mixture of nitrogen and hydrogen with a volume ratio of 3.5:1-4.5:1.

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