Coating and coating production method

Abstract

The present application relates to a coating and a method for preparing the coating. The coating comprises a first amorphous phase coating, a second amorphous phase coating, a third crystalline phase coating and a fourth amorphous phase coating arranged in sequence from a substrate. The method comprises the following steps: forming the first amorphous phase coating on the substrate by using a first laser-induced pulse arc source process; forming the second amorphous phase coating on the first amorphous phase coating by using a second laser-induced pulse arc source process; forming the third crystalline phase coating on the second amorphous phase coating by using a direct current arc source process; and forming the fourth amorphous phase coating on the third crystalline phase coating by using a third laser-induced pulse arc source process, wherein the first laser-induced pulse arc source process, the second laser-induced pulse arc source process and the third laser-induced pulse arc source process all use a laser-induced pulse arc source process.

Description

Technical Field

[0001] This disclosure belongs to the field of coating preparation technology, specifically relating to a composite coating with ultra-high corrosion resistance and a method for preparing the coating. Background Technology

[0002] Currently, coatings with columnar / columnar crystal structures prepared by methods such as vapor deposition, electroplating, and thermal spraying are widely used to improve the protective properties of material surfaces. These columnar crystal coatings are composed of crystal column units grown perpendicular to the material surface, possessing a certain load-bearing capacity and surface density, and are widely used in corrosion resistance and wear resistance applications.

[0003] However, traditional columnar structure coatings generally suffer from problems such as interconnected interstices between columns, numerous grain boundary defects, and uneven interfacial bonding. External corrosive media can easily penetrate and diffuse rapidly along the interstices and grain boundaries, leading to premature coating failure under harsh environments. Furthermore, conventional preparation processes struggle to achieve precise control over column size, orientation, and interstic distribution, further limiting the improvement of coating corrosion resistance.

[0004] Therefore, in order to optimize the corrosion resistance of the coating, it is necessary to optimize the coating structure and improve the coating preparation method to obtain a protective coating with high corrosion resistance and longer service life. Summary of the Invention

[0005] Accordingly, this disclosure proposes a coating with high corrosion resistance and a method for preparing the coating to solve the above problems.

[0006] According to a first aspect of this disclosure, some embodiments of this disclosure provide a coating. The coating includes: a first amorphous phase coating, a second amorphous phase coating, a third crystalline phase coating, and a fourth amorphous phase coating arranged sequentially from a substrate.

[0007] According to a second aspect of this disclosure, some embodiments of this disclosure provide a coating preparation method, characterized by comprising the following steps: forming a first amorphous phase coating on a substrate using a first laser-induced pulsed arc source process; forming a second amorphous phase coating on the first amorphous phase coating using a second laser-induced pulsed arc source process; forming a third crystalline phase coating on the second amorphous phase coating using a DC arc source process; and forming a fourth amorphous phase coating on the third crystalline phase coating using a third laser-induced pulsed arc source process, wherein the first laser-induced pulsed arc source process, the second laser-induced pulsed arc source process, and the third laser-induced pulsed arc source process all employ a laser-induced pulsed arc source process.

[0008] The coating provided in this disclosure, by alternating between crystalline and amorphous phase coatings, can greatly improve the anti-corrosion effect. Simultaneously, the coating also exhibits extremely high temperature resistance, maintaining stable performance even at temperatures up to 1000°C. Additional aspects and advantages of this disclosure will be described, shown, or illustrated in part by way of implementation of the embodiments thereof. Attached Figure Description

[0010] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0011] Figure 1 A schematic diagram illustrating the structure of a coating disposed on a substrate according to certain embodiments of the present disclosure.

[0012] Figure 2 A schematic diagram illustrating the structure of a coating disposed on a substrate according to certain embodiments of the present disclosure.

[0013] Figure 3 A block flowchart illustrating a coating preparation method according to certain embodiments of the present disclosure. Detailed Implementation

[0014] The following disclosure provides various implementations or examples that can be used to achieve different features of this disclosure. Specific examples of components and configurations described below are for simplification purposes. It is understood that these descriptions are illustrative only and are not intended to limit the scope of this disclosure. For example, in the following description, forming a first feature on or over a second feature may include some embodiments in which the first and second features are in direct contact with each other; and may also include some embodiments in which additional components are formed between the first and second features, such that the first and second features may not be in direct contact. Furthermore, component symbols and / or reference numerals may be reused in multiple embodiments of this disclosure. Such reuse is for the purpose of brevity and clarity and does not in itself represent a relationship between the different embodiments and / or configurations discussed.

[0015] While the numerical ranges and parameters used to define the broader scope of this disclosure are approximate values, the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any numerical value inevitably contains standard deviations due to individual test methods. Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range. Alternatively, the term "approximately" means that the actual value falls within the acceptable standard error of the mean, as determined by those skilled in the art to which this disclosure pertains. It is understood that, except for experimental examples, or unless expressly stated otherwise, all ranges, quantities, values, and percentages used herein (e.g., to describe material usage, duration, temperature, operating conditions, quantity ratios, and the like) are modified with "approximately". Therefore, unless otherwise stated, the numerical parameters disclosed in this specification and the accompanying claims are approximate values ​​and are subject to change as needed. At a minimum, these numerical parameters should be understood as the indicated significant digits and values ​​obtained by applying general rounding. In this context, a range of values ​​is expressed as a distance from one endpoint to the other or between the two endpoints; unless otherwise stated, all ranges of values ​​herein include the endpoints.

[0016] As used herein, the term "coating" refers to a continuous or discontinuous covering layer of a certain thickness and function that is applied and attached to the surface of a substrate by physical, chemical or mechanical means to achieve one or more of the following properties: protection, abrasion resistance, corrosion resistance, heat resistance, insulation, conductivity, lubrication, decoration or other predetermined properties.

[0017] Protective coatings are widely used in harsh working conditions such as high temperature and high corrosion. They are mainly prepared by methods such as thermal spraying, electroplating, electroless plating, physical vapor deposition (PVD), and organic coating. Among them, coatings with columnar crystal structures can improve density and mechanical properties, achieving a certain degree of anti-corrosion protection. The inventors have found that coatings formed by thermal spraying have poor thickness control, weak adhesion, numerous pores, and insufficient high-temperature resistance of the sealing agent; coatings formed by electroplating and electroless plating suffer from cracks and are prone to oxidation and failure at high temperatures; coatings formed by physical vapor deposition have micropores and penetrating columnar grain boundaries that allow oxygen diffusion, leading to substrate oxidation; and organic coatings have a low temperature limit, easily failing in high-temperature environments (e.g., above 300°C). The coatings formed by the above preparation methods each contain inherent defects, making existing protective coatings unable to resist corrosion in extremely harsh environments, and their service life cannot meet the requirements for long-term use.

[0018] In view of this, this disclosure proposes a composite coating with multiple coating structures and a method for preparing the same, to overcome the aforementioned technical problems. The coating provided by this disclosure, by alternately setting amorphous and crystalline phase coatings, can improve the overall corrosion resistance of the coating while maintaining its structural strength and stability. Simultaneously, by adjusting the proportion of oxygen in the total gas during the coating preparation process, different oxide phase contents are formed in each coating layer of the composite coating, thereby reducing stress accumulation between the coating layers and optimizing the bonding strength between them.

[0019] Furthermore, this disclosure utilizes laser-induced pulsed arc source technology to remove the oxide layer on the surface of the target to be coated, thereby activating the target surface to provide energy for subsequent ion implantation. On the other hand, it disrupts the grain growth direction and size of the target surface, refining the grains and making them exhibit a disordered isotropic state. This can improve the anti-corrosion effect of the substrate and provide an amorphous structure growth template for subsequent amorphous coating growth, thereby achieving an amorphous columnar structure coating with high corrosion resistance and oxygen diffusion resistance.

[0020] Additional aspects and advantages of embodiments of this disclosure will be described, shown, or illustrated in part by way of implementation of embodiments of this disclosure in the following description.

[0021] According to a first aspect of this disclosure, a multilayer composite coating is provided, in which an amorphous phase coating and a crystalline phase coating are gradually formed on the substrate surface through a stepwise deposition method, thereby achieving a synergistic improvement in mechanical properties and corrosion resistance. Figure 1 A schematic diagram illustrating the structure of a coating disposed on a substrate according to certain embodiments of this disclosure. For example... Figure 1 As shown, in some embodiments, the coating 10 includes a first amorphous phase coating 101, a second amorphous phase coating 102, a third crystalline phase coating 103 and a fourth amorphous phase coating 104 arranged sequentially from the substrate 100.

[0022] As used herein, the term "substrate," also known as a matrix or substrate, refers to the object to which the protective coating of this application is attached. This application does not impose any special restrictions on the specific material of the substrate, which may be any one of the following: metallic, alloy, ceramic, glass, or polymeric materials.

[0023] In some embodiments, the substrate is a metal or alloy component, suitable for mechanical parts subjected to extreme and harsh environments such as high temperature, high humidity, strong corrosion, or strong radiation. In some embodiments, the surface of the substrate can be a smooth surface or a rough surface that has been pretreated (e.g., sandblasting, grinding, polishing).

[0024] As used herein, the term "amorphous phase coating," also known as an amorphous columnar structure coating, refers to an amorphous solid material coating whose internal atoms exhibit a disordered isotropic state and lack a regular crystal structure and grain boundary characteristics. In some embodiments, the amorphous phase coating lacks penetrating grain boundary diffusion channels and can hinder the penetration and diffusion of corrosive media and oxygen elements to achieve high corrosion resistance.

[0025] The amorphous phase coating includes: a first amorphous phase coating, a second amorphous phase coating, and a fourth amorphous phase coating. In some embodiments, a laser-induced process is used to apply a high-frequency laser to the surface of the target to be coated, thereby inducing the formation of an amorphous growth surface. In some embodiments, a pulsed arc source process is used to bombard the amorphous growth surface with high-energy metal particles to implant metal ions and form a metallurgical bond with the material in the substrate. Finally, a coating with an amorphous structure is obtained by adjusting the energy of the reacting gas and the pulsed arc source.

[0026] During the preparation of amorphous phase coatings, the amorphous phase structure in the coating can be affected by adjusting the content of oxygen or silane in the reaction gas. In some embodiments, the amorphous phase coating includes a matrix phase and an oxide phase dispersed in the matrix phase. The oxide phase grains distributed in the coating can exhibit a disordered isotropic state, thereby preventing the formation of periodic crystalline phase units, thus achieving an amorphous phase coating without penetrating grain boundaries.

[0027] In some embodiments, the matrix phase of the amorphous coating includes one or more of an alloy material and a corresponding nitride. In some embodiments, the alloy material may be selected from Cr-based binary and multi-component alloys, such as one or more combinations of CrAl, CrTi, CrZr, CrAlTi, CrZrTi, CrNbFe, and CrFe. Cr-based alloys possess excellent high-temperature oxidation resistance, corrosion resistance, and mechanical strength. In some embodiments, the oxide phase of the amorphous coating includes one or more of an oxide corresponding to the alloy material and a corresponding silicide.

[0028] In some embodiments, different amorphous phase coatings can have their functional requirements optimized by adjusting the process parameters of the oxygen-to-silane ratio. In some embodiments, as the first, second, and fourth amorphous phase coatings are applied, the oxygen or silane content in the preparation process is gradually increased. This increases the oxide phase content in each amorphous phase coating with increasing distance from the substrate, achieving high corrosion resistance in the outer coating while maintaining uniform stress distribution in the inner coating. In some embodiments, the oxide phase content of the second amorphous phase coating is higher than that of the first amorphous phase coating. In some embodiments, the oxide phase content of the fourth amorphous phase coating is higher than that of the second amorphous phase coating. In some embodiments, the oxide phase content of the fourth amorphous phase coating is higher than that of the first amorphous phase coating.

[0029] As used in this article, the term "crystal phase coating," also known as a columnar structure coating, refers to a solid material covering layer with a clear crystal structure and crystal phase composition, in which the internal atoms are arranged in a periodic crystal unit. It can exhibit different crystal morphologies such as columnar crystals and equiaxed crystals.

[0030] The third crystalline phase coating, together with multiple amorphous phase coatings, constitutes a composite coating. By controlling the deposition process parameters and removing oxygen and silane from the reaction gas, crystal units with a clearly defined periodic arrangement are formed within the coating, thereby achieving high mechanical strength and structural stability. This serves as a stress-dispersing layer for the composite coating, enhancing its mechanical strength and high-temperature stability. In some embodiments, the crystalline phase coating includes a matrix phase. In some embodiments, the crystalline phase coating does not include an oxide phase to achieve a close arrangement of its periodically arranged crystal units.

[0031] In some embodiments, the matrix phase of the crystalline coating includes one or more of an alloy material, a corresponding nitride of the alloy material, and a corresponding silicon compound. In some embodiments, the alloy material may be selected from Cr-based binary and multi-component alloys, such as one or more combinations of CrAl, CrTi, CrZr, CrAlTi, CrZrTi, CrNbFe, and CrFe. These Cr-based alloys possess excellent high-temperature oxidation resistance, corrosion resistance, and mechanical strength, and, in synergy with the amorphous coating, can further enhance the overall protective performance of the composite coating. In some embodiments, the crystalline coating and the amorphous coating share the same matrix phase material. In some embodiments, the crystalline coating with a Cr-based alloy as the matrix phase can form a good interfacial bond with the amorphous coating phase, reducing interlayer stress and improving the coating's oxidation resistance and resistance to media penetration under high-temperature and high-corrosion environments.

[0032] The crystal structure of the crystalline phase coating can be controlled to have morphologies such as columnar crystals and equiaxed crystals, depending on the preparation process and functional requirements. In some embodiments, the crystal unit includes a columnar crystal structure, whose grains preferentially grow along a direction perpendicular to the substrate surface, possessing mechanical strength advantages and providing a stable bonding basis for the amorphous phase surface layer. In some embodiments, the columnar crystal structure has a cubic crystal system, which has superior strength and toughness. The third crystalline phase coating has a certain grain boundary structure. Through the sealing effect of the outer fourth amorphous phase layer and the inner second amorphous phase layer, the composite coating of this disclosure can prevent corrosive media from penetrating into the substrate along the grain boundaries.

[0033] Figure 2 A schematic diagram illustrating the structure of a coating 20 disposed on a substrate according to certain embodiments of the present disclosure. For example... Figure 2 As shown, in some embodiments, a first amorphous phase coating 101, a second amorphous phase coating 102, and a third crystalline phase coating 103 are arranged sequentially to form repeating units 110. The coating 20 includes one or more repeating units 110 and a fourth amorphous phase coating 104 arranged sequentially from the substrate 100. By repeatedly setting the repeating coating units 110 composed of the first amorphous phase coating 101, the second amorphous phase coating 102, and the third crystalline phase coating 103, the stress distribution and corrosion resistance of the coating can be further improved. In some embodiments, the number of repeating units 110 in the composite coating can be from 1 to 10.

[0034] The overall thickness of the composite coating and the thicknesses of each amorphous and crystalline phase coating in this disclosure are adjustable according to the substrate operating conditions, protection performance targets, and fabrication processes. In some embodiments, the overall thickness of the composite coating is controlled below 20 μm. In some embodiments, the overall thickness of the composite coating is controlled below 10 μm to optimize the problem of interlayer stress cracking caused by excessive thickness. In some embodiments, the overall thickness of the composite coating is approximately 5 μm to 10 μm. In some embodiments, the overall thickness of the composite coating is approximately 6 μm to 8 μm. This thickness range balances protection performance and coating flexibility, adapting to long-term use requirements in harsh environments such as high temperature and high corrosion, while avoiding impact on the dimensional accuracy of precision components.

[0035] The thickness of each amorphous phase coating is precisely controlled according to its different functions, as detailed below:

[0036] In some embodiments, the thickness of the first amorphous phase coating directly attached to the substrate surface ranges from about 0.2 μm to 0.8 μm. This thickness ensures sufficient contact between the coating and the substrate, enhances the bonding strength, and provides a smooth and stable adhesion base for the subsequent deposition of functional layers.

[0037] In some embodiments, the thickness of the second amorphous phase coating disposed on the first amorphous phase coating ranges from about 1.0 μm to 2.0 μm. As a thickening layer, this thickness can effectively block the diffusion of corrosive media to the coating. At the same time, the thickness of this layer should not be too thick to avoid generating excessive internal stress that could cause the coating to peel off.

[0038] In some embodiments, the thickness of the third crystalline phase coating, which serves as an intermediate reinforcing layer, ranges from about 0.2 μm to 0.8 μm. This thickness can fully utilize the mechanical strength and high-temperature stability of the crystalline phase coating, resist mechanical wear and thermal shock, and at the same time, it can be used to adjust the overall coating stress distribution and reduce the risk of coating peeling.

[0039] In some embodiments, the outermost fourth amorphous phase coating has a thickness ranging from approximately 1.0 μm to 6.0 μm. This layer focuses on tight sealing, with increased thickness primarily aimed at improving wear and corrosion resistance. In some embodiments, to achieve effective barrier against corrosive media, the thickness of the fourth amorphous phase coating is substantially equal to the sum of the thicknesses of all other internal coatings. In some embodiments, the thickness of the fourth amorphous phase coating is substantially equal to the sum of the thicknesses of the first, second, and third amorphous phase coatings.

[0040] In some embodiments, the composite coating comprises multiple repeating coating units, where the thickness of each amorphous phase coating in the repeating coating unit ranges from approximately 0.5 μm to 0.8 μm, and the thickness of the crystalline phase coating ranges from approximately 0.2 μm to 0.5 μm. This optimizes the synergistic effect of the two, namely, improving mechanical properties through the crystalline phase coating and blocking the penetration of corrosive media through the density of the amorphous phase coating. In some embodiments, the thickness of each amorphous phase coating in the repeating coating unit exhibits a gradient distribution with increasing distance from the substrate, with the thickness of the amorphous phase coating decreasing closer to the substrate and increasing further away from the substrate. This optimizes the stress distribution of the coating structure and reduces the risk of coating detachment.

[0041] According to a second aspect of this disclosure, this disclosure provides a method for preparing the multilayer composite coating described in the above embodiments. Figure 3 This demonstration presents a block flowchart of a coating preparation method according to certain embodiments of the present disclosure. In some embodiments, the method includes the following steps: S101 forming a first amorphous phase coating on a substrate using a first laser-induced pulsed arc source process; S102 forming a second amorphous phase coating on the substrate using a second laser-induced pulsed arc source process; S103 forming a third crystalline phase coating on the second amorphous phase coating using a DC arc source process; and S104 forming a fourth amorphous phase coating on the third crystalline phase coating using a third laser-induced pulsed arc source process, unless otherwise stated, in sequence. It should be understood that in some embodiments, the order of some steps may be adjusted, or some steps may be repeated, without departing from the spirit and scope of protection of the present disclosure.

[0042] In this application, the first laser-induced pulsed arc source process, the second laser-induced pulsed arc source process, and the third laser-induced pulsed arc source process are all essentially based on the core process principle of laser-induced pulsed arc source. The difference between the two lies in the precise control of the laser-induced pulsed arc source process parameters. By adjusting different process parameters, the composition, function, and thickness of the coatings prepared by each process are adapted to different requirements, respectively corresponding to the preparation needs of different amorphous coatings in the composite coating.

[0043] As used herein, the term "laser-induced pulsed arc source process" refers to a novel vapor deposition process that combines laser induction with pulsed arc source discharge to prepare amorphous phase coatings. In some embodiments, the laser-induced pulsed arc source process includes a laser induction step, which includes: placing the target to be coated in an argon atmosphere; applying a high-frequency laser to the surface of the target to be coated to activate the surface, thereby providing a growth template for the amorphous phase coating.

[0044] In some embodiments, the main control of process parameters includes: laser parameters (laser power, laser frequency, scanning speed), pulsed arc source parameters (pulse current, power, pulse frequency, duty cycle), reaction gas source parameters (oxygen to silane ratio, injection rate), and deposition parameters (deposition time, deposition rate). By differentially controlling the above parameters, the first laser-induced pulsed arc source process, the second laser-induced pulsed arc source process, and the third laser-induced pulsed arc source process can respectively prepare amorphous phase coatings that meet functional requirements.

[0045] In some embodiments, the laser parameters used in the laser induction step include: power from 1 kW to 10 kW, frequency from 100 Hz to 1000 Hz, and scanning speed from 1 mm / s to 100 mm / s. It should be understood that the timing of the laser induction step can be flexibly selected according to actual operating conditions. In some embodiments, the laser induction step is performed when each laser-induced pulse arc source process is started. In some embodiments, the laser induction step is performed only when the first laser-induced pulse arc source process is started. In some embodiments, the laser induction step is selected to be performed in a specific laser-induced pulse arc source process, for example, the third laser-induced pulse arc source process.

[0046] In some embodiments, the laser-induced pulsed arc source process includes a pulsed arc source step, which includes: placing the target to be coated into a vacuum environment, introducing a reaction gas, argon and nitrogen, wherein the first reaction gas includes one or more of oxygen or silane; subsequently, applying a pulsed arc to the target material through an arc power source to deposit a corresponding amorphous phase coating.

[0047] In some embodiments, the reactive gas used in the laser-induced pulsed arc source process accounts for approximately 5% to 50% of the total gas content. In some embodiments, as the amorphous phase coatings are sequentially added, the content of the reactive gas used in the laser-induced pulsed arc source process gradually increases to improve the density of the amorphous phase coatings and reduce stress buildup in the composite coating. In some embodiments, the content of the reactive gas used in the second laser-induced pulsed arc source process is greater than that used in the first laser-induced pulsed arc source process; and the content of the reactive gas used in the third laser-induced pulsed arc source process is greater than that used in the second laser-induced pulsed arc source process. In some embodiments, for the outermost fourth amorphous phase coating, the content of the reactive gas used in its preparation process accounts for more than 40% of the total gas content to form a highly dense and grain-boundary-free amorphous phase coating.

[0048] In some embodiments, the arc power supply parameters used in the laser-induced pulsed arc source process include: a power range of approximately 5 kW to 15 kW, a pulse frequency range of approximately 5 kHz to 15 kHz, and a void ratio range of approximately 60%-90%. The amorphous phase coating is deposited by applying an arc power supply with a high void ratio, which effectively improves the density of the coating while reducing stress buildup. In some embodiments, as the amorphous phase coatings are sequentially added, the void ratio of the arc power supply used in the laser-induced pulsed arc source process is gradually increased to improve the density of the amorphous phase coating and reduce stress buildup in the composite coating. In some embodiments, the void ratio of the arc power supply used in the second laser-induced pulsed arc source process is greater than that used in the first laser-induced pulsed arc source process; and the void ratio of the arc power supply used in the third laser-induced pulsed arc source process is greater than that used in the second laser-induced pulsed arc source process. In some embodiments, for the outermost fourth amorphous phase coating, the arc power source used in its preparation process has a void ratio of more than 80% to form a highly dense and grain-boundary-free amorphous phase coating, thereby achieving a coating with extremely high corrosion resistance.

[0049] In some embodiments, the arc power supply used in the first laser-induced pulsed arc source process has a current range of approximately 60A to 80A. In some embodiments, the arc power supply used in the second laser-induced pulsed arc source process has a current range of approximately 120A to 160A. In some embodiments, the arc power supply used in the third laser-induced pulsed arc source process has a current range of approximately 60A to 80A. By using a current intensity of approximately twice that of the arc power supply used in the second laser-induced pulsed arc source process compared to the first laser-induced pulsed arc source process, a second amorphous phase coating can be rapidly formed.

[0050] In some embodiments, the DC arc source process includes: placing the target material to be coated into a cavity and introducing nitrogen gas; applying a DC arc to the target material using a DC arc power supply to deposit the corresponding coating, wherein the arc power supply parameters include: a current range of 60-80A, a power of 5kW-15kW, and a pulse frequency of 5kHz-15kHz. The empty area ratio of the DC arc source process is 0% to form a crystalline phase coating with periodically arranged crystal units.

[0051] As explained earlier, the target material used in laser-induced pulsed arc source processes or DC arc source processes comprises an alloy material. This alloy material can be selected from Cr-based binary and multi-element alloys, such as one or more combinations of CrAl, CrTi, CrZr, CrAlTi, CrZrTi, CrNbFe, and CrFe. The functions and characteristics of using alloy materials as target materials will not be elaborated here. In some embodiments, the molar content of Cr in the target material is between 30% and 50%. In some embodiments, the target materials used in the first, second, and third laser-induced pulsed arc source processes have the same material composition. In some embodiments, the target materials used in the first, second, and third laser-induced pulsed arc source processes have different material compositions.

[0052] In some embodiments, steps S101 to S103 can be executed repeatedly to form one or more repeating units of a first amorphous phase coating, a second amorphous phase coating and a third crystalline phase coating arranged in sequence. Then, after obtaining a predetermined number of repeating units, step S104 is executed to obtain a conformal coating, which includes multiple alternating amorphous phase coatings and crystalline phase coatings, which can significantly improve the corrosion resistance and durability of the coating.

[0053] Before applying a coating using a laser-induced pulsed arc source or a DC arc source, the following pretreatment steps can be performed individually or in combination, depending on the process requirements. The process parameters for each pretreatment step are set independently, and all steps are completed within the furnace cavity during the coating process:

[0054] 1. Alumina sandblasting cleaning

[0055] In some embodiments, the substrate surface is subjected to a sandblasting cleaning process, in which 2000-mesh alumina particles are used to sandblast the substrate surface to remove dirt, followed by cleaning with water and ultrasonic vibration.

[0056] 2. Vacuum pretreatment of the furnace cavity

[0057] In some embodiments, the internal gas pressure of the furnace cavity is first evacuated to 10. -3For pressures below 100 Pa, the evacuation time is 5 minutes to remove impurities from the furnace chamber, preventing reaction gases from contaminating the coating during subsequent coating processes and ensuring coating purity.

[0058] 3. Furnace cavity temperature pretreatment

[0059] In some embodiments, a heating device inside the furnace cavity is used to control the temperature of the furnace cavity, so that the internal temperature of the furnace cavity is stable between 400°C and 500°C, and the heating time is 10 minutes to 30 minutes, so as to provide a suitable temperature environment for subsequent coating processes and improve the adhesion between the coating and the substrate.

[0060] 4. Pretreatment of furnace gas introduction

[0061] In some embodiments, a mixture of argon or nitrogen is introduced into the vacuum-heated furnace cavity to bring the pressure inside the furnace cavity to 2 Pa to 10 Pa, and a bias power supply of 800 V to 1000 V is turned on for 10 to 30 minutes.

[0062] The above-mentioned alumina sandblasting cleaning, cavity vacuum pretreatment, cavity temperature pretreatment, and furnace gas introduction pretreatment steps can be implemented individually or in combination and implemented sequentially. The process parameters of each step are not affected by the implementation of other steps. After all pretreatment steps are completed, the coating step of laser-induced pulsed arc source process or DC arc source process is performed.

[0063] In some embodiments, after the coating step, a further heating step is included: placing the coated product in a heating furnace, raising the furnace temperature to approximately 900°C to 1000°C, and heating for 1 to 2 hours. This heating step can eliminate residual stress within the coating, promote interlayer element diffusion and interfacial bonding, stabilize the coating phase structure, and improve coating density and high-temperature stability.

[0064] To further reveal the technical solution of this disclosure and the technical effects it can achieve, specific embodiments are provided below, and salt spray tests are conducted on the embodiments and comparative examples to verify the beneficial effects of the technical solution of this disclosure. Detailed Implementation

[0065] Comparative Example

[0066] Using a coating apparatus, individual coatings, as shown in Table 1, were applied to the substrate surface as multiple comparative examples. Table 1 lists whether a laser-induced step was performed during coating preparation, the target material composition, the gas composition introduced during the coating process, and the coating thickness:

[0067] Table 1

[0068]

[0069] The specific process and operation are as follows: YG6 cemented carbide is used as the test substrate, and the substrate size is 15. 15 6mm; Coating process parameters are as follows: using the corresponding target material composition, coating temperature 400℃, arc power power 2kw, pulse frequency 10KHZ, introducing the corresponding gas composition, coating gas pressure 2Pa; after coating, heat treatment is performed: the test substrate is placed in a heating furnace and heated at 1000℃ for 2 hours.

[0070] Example

[0071] The specific preparation process of Embodiment 1 of this disclosure is performed using a laser-induced etching device as follows:

[0072] 1. Pretreatment steps: The test substrate is subjected to alumina sandblasting cleaning, furnace cavity vacuum pretreatment, furnace cavity temperature pretreatment, and furnace cavity gas introduction pretreatment.

[0073] 2. Fill the furnace cavity with a mixture of hydrogen and argon gas, adjust the furnace cavity pressure to 2Pa, turn on the bias power supply, set the bias parameter to 800V, and hold for 10 minutes.

[0074] 3. First laser-induced pulsed arc source process: Laser induction step is performed on the target to be coated; the arc target is turned on, and an alloy target material with the composition of Cr60Al40 is selected. The arc power supply parameters are set as follows: current 60A, power 2kW, pulse frequency 10kHz, duty cycle 80%. Nitrogen, argon and oxygen are introduced into the furnace chamber, with oxygen accounting for 20%. The first amorphous phase coating is formed on the target to be coated. The coating time is 10 minutes and the coating thickness is 0.5 μm.

[0075] 4. Second laser-induced pulsed arc source process: Laser induction step is performed on the target to be coated; the arc target is turned on, and an alloy target material with the composition of Cr70Al30 is selected. The arc power supply parameters are set as follows: current 120A, power 2kW, pulse frequency 10kHz, duty cycle 80%. Nitrogen, argon and oxygen are introduced into the furnace cavity, with oxygen accounting for 30%. A second amorphous phase coating is formed on the first amorphous phase coating. The coating time is 20 minutes and the coating thickness is 1 μm.

[0076] 5. DC arc source process: Turn on the arc target, select an alloy target material with composition of Cr60Al40, and set the arc power supply parameters: current 80A, power 2kW, pulse frequency 10kHz, duty cycle 0%. Introduce pure nitrogen into the furnace cavity to form a third crystalline phase coating on the second amorphous phase coating. The coating time is 5 minutes and the coating thickness is 0.2 μm.

[0077] 6. Repeat the first laser-induced pulse arc source process, the second laser-induced pulse arc source process, and the DC arc source process twice.

[0078] 7. Third laser-induced pulsed arc source process: Laser induction step is performed on the target to be coated; the arc target is turned on, and an alloy target material with the composition of Cr60Al40 is selected. The arc power supply parameters are set as follows: current 80A, power 2kW, pulse frequency 10kHz, duty cycle 80%. Nitrogen, argon and oxygen are introduced into the furnace cavity, with oxygen accounting for 50%. A fourth amorphous phase coating is formed on the target to be coated. The coating time is 60 minutes. The entire coating process is completed. The total coating thickness of the resulting coating sample is 8 μm.

[0079] 8. Heat treatment: Place the coated sample in a heating furnace and heat at 1000℃ for 2 hours.

[0080] Based on a preparation process largely the same as in Example 1, Examples 2-5 were prepared sequentially. In Example 2, the introduced gases from the first laser-induced pulsed arc source process to the third laser-induced pulsed arc source process were replaced with nitrogen, argon, and silane. In Example 3, the introduced gases from the first laser-induced pulsed arc source process to the third laser-induced pulsed arc source process were replaced with oxygen, argon, and silane. In Example 4, the introduced gases from the first laser-induced pulsed arc source process to the third laser-induced pulsed arc source process were replaced with argon and oxygen. In Example 5, the target material was replaced with Ti50Cr50.

[0081] The coating samples from the above examples and comparative examples, after heat treatment, were first observed to see if oxidation or peeling failure occurred. Then, salt spray testing was conducted according to the national standard GB / T 10125-2021. During the test, the corrosion status of the sample surface was observed. When the first corrosion point appeared on the sample surface, the test was immediately terminated. The total time from the start of the test to the appearance of the corrosion point was recorded. This time is the salt spray corrosion resistance life of the coating, which is used to evaluate the corrosion protection performance of the coating.

[0082] The heat treatment and salt spray test data for the comparative examples and embodiments are shown in Table 2 below:

[0083] Table 2

[0084]

[0085] Testing revealed that the salt spray corrosion resistance of the single-layer coating samples in the comparative examples could not exceed 60 hours, and the difference in salt spray corrosion resistance was not significant compared to the uncoated sample in Comparative Example 1. In contrast, the salt spray corrosion resistance of the composite coating samples provided in this embodiment can reach an average of nearly 500 hours, with a minimum of 300 hours.

[0086] As can be seen from the above, the multilayer composite coating prepared by the process described in this disclosure, by alternately setting crystalline phase coating and amorphous phase coating, can significantly improve the corrosion resistance and protection performance of the coating. As verified by the GB / T 10125-2021 neutral salt spray test, its anti-corrosion effect can reach more than 30 times that of conventional ordinary PVD hard coating, effectively blocking the penetration of corrosive media for a long time and solving the technical problems of insufficient corrosion resistance and premature failure of traditional coatings.

[0087] Meanwhile, the composite coating also has excellent high-temperature stability, and can be used for a long time under high-temperature conditions of 1000℃. The internal phase structure, mechanical properties and protective properties of the coating can remain stable without cracking, peeling or oxidation failure. It combines high corrosion resistance and high temperature resistance, is suitable for extremely harsh operating environments, and greatly extends the service life and replacement cycle of the base components, thus having high industrial application value.

[0088] The foregoing outlines several embodiments and detailed features of this disclosure. The embodiments described in this disclosure can readily serve as the basis for designing or modifying other processes and structures for performing the same or similar purposes and / or obtaining the same or similar advantages of the embodiments introduced herein. These equivalent constructions do not depart from the spirit and scope of this disclosure and various changes, substitutions, and modifications can be made without departing from the spirit and scope of this disclosure.

Claims

1. A coating, characterized in that, The coating comprises: a first amorphous phase coating, a second amorphous phase coating, a third crystalline phase coating, and a fourth amorphous phase coating arranged sequentially from the substrate.

2. The coating according to claim 1, characterized in that, The first amorphous phase coating, the second amorphous phase coating, and the fourth amorphous phase coating include a matrix phase and an oxide phase dispersed in the matrix phase. The matrix phase includes one or more of an alloy material and a corresponding nitride of the alloy material, and the oxide phase includes one or more of an oxide corresponding to the alloy material and a corresponding silicide of the alloy material.

3. The coating according to claim 2, characterized in that, The content of the oxide phase in the second amorphous phase coating is higher than the content of the oxide phase in the first amorphous phase coating.

4. The coating according to claim 2, characterized in that, The oxide phase content of the fourth amorphous phase coating is higher than that of the second amorphous phase coating, and the oxide phase content of the fourth amorphous phase coating is higher than that of the first amorphous phase coating.

5. The coating according to claim 1, characterized in that, The third crystalline phase coating includes a matrix phase, wherein the matrix phase includes one or more of an alloy material, a nitride corresponding to the alloy material, and a silicon compound corresponding to the alloy material.

6. The coating according to claim 2 or 5, characterized in that, The alloy material mentioned above includes one or more of the following: CrAl, CrTi, CrZr, CrAlTi, CrZrTi, CrNbFe, and CrFe.

7. The coating according to claim 1, characterized in that, The third crystalline phase coating comprises periodically arranged crystal units, wherein the periodically arranged crystal units include columnar crystal structures.

8. The coating according to claim 7, characterized in that, The columnar crystal structure belongs to the cubic crystal system.

9. The coating according to claim 1, characterized in that, The first amorphous phase coating, the second amorphous phase coating, and the third crystalline phase coating are arranged in sequence to form repeating units, and the coating includes one or more repeating units arranged in sequence from the substrate and a fourth amorphous phase coating.

10. The coating according to claim 1, characterized in that, The total thickness of the coating is less than or equal to 10 μm.

11. The coating according to claim 1, characterized in that, The thickness of the first amorphous phase coating ranges from 0.2 μm to 0.8 μm, the thickness of the second amorphous phase coating ranges from 1.0 μm to 2.0 μm, the thickness of the third crystalline phase coating ranges from 0.2 μm to 0.8 μm, and the thickness of the fourth amorphous phase coating ranges from 1.0 μm to 6.0 μm.

12. A coating preparation method, characterized in that, It includes the following steps: A first amorphous phase coating is formed on a substrate using a first laser-induced pulsed arc source process; A second amorphous phase coating is formed on the first amorphous phase coating using a second laser-induced pulsed arc source process; A third crystalline phase coating is formed on the second amorphous phase coating using a DC arc source process; and A fourth amorphous phase coating is formed on the third crystalline phase coating using a third laser-induced pulsed arc source process, wherein the first laser-induced pulsed arc source process, the second laser-induced pulsed arc source process, and the third laser-induced pulsed arc source process all employ laser-induced pulsed arc source processes.

13. The method according to claim 12, characterized in that, The laser-induced pulsed arc source process further includes a laser induction step, which includes: The target to be coated is placed in an argon atmosphere; and A laser is applied to the surface of the substrate, wherein the laser parameters include: power of 1 kW to 10 kW, frequency of 100 Hz to 1000 Hz, and scanning speed of 1 mm / s to 100 mm / s.

14. The method according to claim 123, characterized in that, The laser-induced pulsed arc source process Includes the following steps: The target to be coated is placed in the cavity, and a reaction gas, argon gas, and nitrogen gas are introduced. The reaction gas includes one or more of oxygen and silane, and the proportion of the reaction gas in the total gas ranges from 5% to 50%. A pulsed electric arc is applied to a target material by an arc power source to deposit a corresponding coating. The parameters of the arc power source include: power of 5 kW-15 kW, pulse frequency of 5 kHz-15 kHz, and empty ratio of 60%-90%.

15. The method according to claim 14, characterized in that, The arc power supply parameters of the first laser-induced pulsed arc source process include a current range of 60 A to 80 A; the arc power supply parameters of the second laser-induced pulsed arc source process include a current range of 120 A to 160 A; and the arc power supply parameters of the third laser-induced pulsed arc source process include a current range of 60-80 A.

16. The method according to claim 14, characterized in that, The empty percentage of the pulsed arc used in the second laser-induced pulsed arc source process is greater than or equal to the empty percentage of the pulsed arc used in the first laser-induced pulsed arc source process.

17. The method according to claim 14, characterized in that, The content of the reactive gas used in the second laser-induced pulsed arc source process is greater than the content of the reactive gas used in the first laser-induced pulsed arc source process; and the content of the reactive gas used in the third laser-induced pulsed arc source process is greater than the content of the reactive gas used in the second laser-induced pulsed arc source process.

18. The method according to claim 14, characterized in that, The target material includes one or more of CrAl, CrTi, CrZr, CrAlTi, CrZrTi, CrNbFe, and CrFe, wherein the molar content of Cr element in the target material is between 30% and 50%.

19. The method according to claim 12, characterized in that, The DC arc source process includes: Place the target object to be coated into the cavity and introduce nitrogen gas; A DC arc is applied to a target material by a DC arc power supply to deposit a corresponding coating. The parameters of the arc power supply include: current range of 60-80A, power of 5kW-15kW, and pulse frequency of 5kHz-15kHz.

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