Wear-resistant friction-reducing titanium alloy coating and method of making

Abstract

The application provides a wear-resistant and friction-reducing titanium alloy coating and a preparation method, and relates to the technical field of wear-resistant and friction-reducing coatings.The wear-resistant and friction-reducing titanium alloy coating is composed of a matrix phase, a reinforcing phase and a lubricating phase.The matrix phase is a titanium alloy.The lubricating phase is one of silver, hexagonal boron nitride and barium fluoride.The reinforcing phase is a combination of cubic boron nitride ceramic particles and a hard phase.The hard phase is TiN, TiB and Ti2Ni.The wear-resistant and friction-reducing titanium alloy coating has excellent wear-resistant and friction-reducing performance, can play a good protective role on the surface of the matrix at room temperature, and effectively improves the service life of the matrix.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant and friction-reducing coating technology, and particularly to a wear-resistant and friction-reducing titanium alloy coating and its preparation method. Background Technology

[0002] Because high-pressure compressor blades will inevitably wear down under high-speed service conditions, the coating on the blade surface is prone to peeling, flaking, and even cracking. This can lead to structural defects or damage to the high-pressure compressor, as well as ship power failure. This not only seriously affects the performance, lifespan, and reliability of the ship's power plant, but also significantly increases maintenance costs. Summary of the Invention

[0003] To address the aforementioned problems, in a first aspect, the present invention provides a wear-resistant and friction-reducing titanium alloy coating, wherein the wear-resistant and friction-reducing titanium alloy coating comprises a matrix phase, a reinforcing phase, and a lubricating phase, wherein the matrix phase is a titanium alloy; the lubricating phase is one of silver, hexagonal boron nitride, and barium fluoride; the reinforcing phase is a combination of cubic boron nitride ceramic particles and a hard phase; and the hard phase is TiN, TiB, and Ti2Ni.

[0004] Preferably, the lubricating phase in the wear-resistant and friction-reducing titanium alloy coating has a volume fraction of 0.1-10% and a particle size distribution of 0.1μm-20μm.

[0005] Preferably, the cubic boron nitride ceramic particles in the reinforcing phase have a volume fraction of 5-20% in the wear-resistant and friction-reducing titanium alloy coating, and a particle size distribution of 1μm-40μm.

[0006] Preferably, the lubricating phase, the cubic boron nitride ceramic particles, and the hard phase are uniformly dispersed in the wear-resistant and friction-reducing titanium alloy coating.

[0007] In a second aspect, the present invention provides a method for preparing the wear-resistant and friction-reducing titanium alloy coating described in the first aspect above, the method comprising:

[0008] S1, the matrix phase material and the lubricating phase material are mixed in a certain proportion and then ball-milled to obtain composite powder; wherein, the matrix phase material is titanium alloy powder and the lubricating phase material is one of silver, hexagonal boron nitride and barium fluoride powder.

[0009] S2, the composite powder and the reinforcing phase raw material are mixed mechanically according to the specified ratio to obtain a mixed powder; wherein, the reinforcing phase raw material is nickel-coated cubic boron nitride ceramic particles;

[0010] S3, the mixed powder is clad onto the surface of a titanium alloy substrate using a high-speed laser to prepare a wear-resistant and friction-reducing titanium alloy coating; wherein, during the high-speed laser cladding process, the nickel-coated cubic boron nitride ceramic particles react in situ with the high-temperature titanium alloy powder to generate a hard phase, the hard phase being TiN, TiB and Ti2Ni.

[0011] Preferably, the average thickness of the nickel layer on the surface of the nickel-coated cubic boron nitride ceramic particles is 1 μm-5 μm.

[0012] Preferably, the titanium alloy matrix is ​​TC11 high-temperature titanium alloy.

[0013] Preferably, the titanium alloy substrate and the wear-resistant and friction-reducing titanium alloy coating are metallurgically bonded.

[0014] Preferably, in the mixed powder, the mass fraction of the lubricating phase raw material is 1-25 wt.%, the mass fraction of the reinforcing phase raw material is 20-40 wt.%, and the remainder is the mass fraction of the matrix phase raw material; the sum of the mass fractions of the lubricating phase raw material, the reinforcing phase raw material, and the matrix phase raw material is 100%.

[0015] Preferably, the process parameters for the high-speed laser cladding are: laser power 1.5kW-2.5kW, cladding rate 100mm / s-300mm / s, protective gas flow rate 1L / min-5L / min, and overlap rate 50-80%.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] This invention provides a wear-resistant and friction-reducing titanium alloy coating and its preparation method, relating to the field of wear-resistant and friction-reducing coating technology. The wear-resistant and friction-reducing titanium alloy coating consists of a matrix phase, a reinforcing phase, and a lubricating phase. The matrix phase is a titanium alloy; the lubricating phase is one of silver, hexagonal boron nitride, and barium fluoride; the reinforcing phase is a combination of cubic boron nitride ceramic particles and a hard phase; and the hard phase is TiN, TiB, and Ti2Ni. The wear-resistant and friction-reducing titanium alloy coating provided by this invention exhibits excellent wear resistance and friction-reducing properties, providing good protection on the substrate surface at room temperature and effectively extending the service life of the substrate.

[0018] In this embodiment of the invention, by utilizing the interaction between the matrix phase and the reinforcing phase, the hardness and wear resistance of the titanium alloy coating are greatly increased, giving the coating excellent wear resistance. Furthermore, by adding a lubricating phase and controlling the decomposition of the lubricating phase, the self-lubricating properties of the coating are effectively improved simultaneously. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 The images show the surface and cross-sectional morphology of nickel-coated cubic boron nitride ceramic particles in an embodiment of the present invention.

[0021] Figure 2 The images show the macroscopic cross-sectional morphology and XRD pattern of the titanium alloy coating obtained in Example 1 of this invention.

[0022] Figure 3 The image shows the macroscopic cross-sectional morphology and XRD pattern of the titanium alloy coating obtained in Example 2 of this invention.

[0023] Figure 4 The images show the macroscopic cross-sectional morphology and XRD pattern of the titanium alloy coating obtained in Example 3 of this invention. Detailed Implementation

[0024] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0025] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0026] In a first aspect, the present invention provides a wear-resistant and friction-reducing titanium alloy coating, wherein the wear-resistant and friction-reducing titanium alloy coating is composed of a matrix phase, a reinforcing phase and a lubricating phase, wherein the matrix phase is a titanium alloy; the lubricating phase is one of silver, hexagonal boron nitride and barium fluoride; the reinforcing phase is a combination of cubic boron nitride ceramic particles and a hard phase; and the hard phase is TiN, TiB and Ti2Ni.

[0027] The lubricating phase cannot contain graphite, nickel-coated graphite, tungsten disulfide, or MoS2. The main reason is that graphite, nickel-coated graphite, tungsten disulfide, and MoS2 have low decomposition temperatures and cannot withstand the large amount of heat input during the ultra-high-speed laser cladding coating preparation process. They are prone to decomposition during coating preparation, failing to guarantee a good friction-reducing and lubricating effect.

[0028] The reinforcing phase provided by this invention consists of two parts. One part is formed by the in-situ reaction of partially decomposed nickel-coated cubic boron nitride ceramic particles with the matrix phase during the coating preparation process to generate Ti2Ni, TiN, and TiB (wherein, the matrix phase provides the Ti source, and the decomposition of the nickel-coated cubic boron nitride ceramic particles provides the Ni source, N source, and B source). The other part is the remaining cubic boron nitride ceramic particles that are not completely decomposed after some of the cubic boron nitride in the nickel-coated cubic boron nitride ceramic particles are decomposed.

[0029] The wear-resistant and friction-reducing titanium alloy coating obtained in this embodiment of the invention utilizes the decomposition and regulation of nickel-coated cubic boron nitride particles to induce an in-situ reaction with the matrix phase to generate TiNi, TiB, and Ti2Ni hard phases. This significantly ensures the hardness and wear resistance of the wear-resistant and friction-reducing titanium alloy coating, making it suitable as a protective coating for high-pressure compressor blades. The partial decomposition of the cubic boron nitride particles releases B and N atoms that react with Ti in the matrix phase to generate TiNi and TiB hard phases in situ. Simultaneously, a portion of the nickel coating reacts with the titanium in the matrix phase to generate Ti2Ni hard phase, achieving a dispersion strengthening effect; another portion of the nickel enters the in-situ generated TiN and TiB lattice, achieving a solid solution strengthening effect.

[0030] Preferably, the lubricating phase in the wear-resistant and friction-reducing titanium alloy coating has a volume fraction of 0.1-10% and a particle size distribution of 0.1μm-20μm.

[0031] Preferably, the cubic boron nitride ceramic particles in the reinforcing phase have a volume fraction of 5-20% in the wear-resistant and friction-reducing titanium alloy coating, and a particle size distribution of 1μm-40μm.

[0032] It should be noted that since the volume fraction of the TiNi, TiB, and Ti2Ni hard phases in the reinforcing phase is inconvenient to measure, the remaining volume fraction (70-94.9%) is the sum of the volume fractions of the matrix phase and the hard phase.

[0033] Preferably, the lubricating phase, the cubic boron nitride ceramic particles, and the hard phase are uniformly dispersed in the wear-resistant and friction-reducing titanium alloy coating.

[0034] Specifically, the lubricating phase is uniformly dispersed in the wear-resistant and friction-reducing titanium alloy coating, giving the coating excellent friction-reducing properties and ensuring relatively uniform friction-reducing performance of the compressor blades. The cubic boron nitride ceramic particles and hard phase are also uniformly dispersed in the wear-resistant and friction-reducing titanium alloy coating, resulting in relatively uniform hardness and wear resistance of the titanium alloy coating at various locations. If the components in the wear-resistant and friction-reducing titanium alloy coating are not uniformly distributed, the resulting coating performance will be uneven. Areas on the blade surface with poor wear-resistant and friction-reducing effects will still experience peeling, flaking, and cracking. Even with a wear-resistant and friction-reducing coating, the compressor blades will still not be wear-resistant.

[0035] This invention significantly increases the hardness and wear resistance of titanium alloy coatings by utilizing the interaction between the matrix phase and the reinforcing phase, giving the coatings excellent wear resistance. Furthermore, by adding a lubricating phase and controlling its decomposition, the self-lubricating properties of the coating are simultaneously and effectively improved.

[0036] In a second aspect, the present invention provides a method for preparing the wear-resistant and friction-reducing titanium alloy coating described in the first aspect above, the method comprising:

[0037] S1, the matrix phase material, lubricating phase material and reinforcing phase material are mixed in a certain proportion and then ball-milled to obtain composite powder; wherein, the matrix phase material is titanium alloy powder and the lubricating phase material is one of silver, hexagonal boron nitride and barium fluoride.

[0038] S2, after the composite powder and the reinforcing phase raw material are mixed in a certain proportion, the mixture is mechanically mixed to obtain a mixed powder; wherein, the reinforcing phase raw material is nickel-coated cubic boron nitride ceramic particles;

[0039] S3, the mixed powder is clad onto the surface of a titanium alloy substrate using a high-speed laser to prepare a wear-resistant and friction-reducing titanium alloy coating; wherein, during the high-speed laser cladding process, the nickel-coated cubic boron nitride ceramic particles react in situ with the titanium alloy powder to generate a hard phase, the hard phase being TiN, TiB and Ti2Ni.

[0040] The wear-resistant and friction-reducing titanium alloy coating provided by the first aspect of the present invention can be prepared by conventional laser cladding coating preparation methods, such as thermal spraying, to prepare the high-temperature wear-resistant and friction-reducing coating provided by the first aspect.

[0041] However, because the wear-resistant and friction-reducing coating prepared by thermal spraying is mechanically bonded to the substrate, the bonding strength is relatively poor, and the coating is prone to peeling off under the centrifugal force and friction of the high-speed rotating blades. Furthermore, in conventional laser cladding, to ensure the solid powder material is fully melted after being fed into the molten pool, the molten pool provides heat to melt the raw material, resulting in a large heat input. Therefore, conventional laser cladding has a significant thermal impact on the substrate and a high coating dilution rate, causing severe decomposition of the raw material powder. This means that the original properties (friction-reducing properties) of the raw material powder cannot be preserved to the maximum extent in the coating, thus greatly affecting the coating's friction-reducing performance.

[0042] Furthermore, the present invention provides a method for preparing a wear-resistant and friction-reducing titanium alloy coating. The wear-resistant and friction-reducing titanium alloy coating provided in the first aspect is prepared by the preparation method provided in the second aspect of the present invention, which avoids the severe decomposition of important components during the coating preparation process. Therefore, compared with conventional coating preparation methods, the coating obtained by the preparation method provided by the present invention has better self-lubricating effect and can obtain a high-performance titanium alloy coating to the greatest extent.

[0043] Specifically, steps S1 and S2 include:

[0044] First, the matrix phase raw material and the lubricating phase raw material are ball-milled at a ball-to-material ratio of 5:1, with a ball mill speed of 300 r / min and a ball milling time of 3 h. Then, the mixture is sieved to obtain a composite powder of the lubricating phase and the matrix phase. The composite powder is then mechanically mixed with nickel-coated cubic boron nitride ceramic particles at a speed of 200 r / min for 1 h to ensure uniform mixing of the powder, thus obtaining the mixed powder in S2.

[0045] Specifically, the preparation method also includes:

[0046] Before preparing the titanium alloy coating, the substrate surface is pretreated. The pretreatment involves grinding and polishing the substrate to remove surface oxide layers, oil stains and other contaminants, and finally cleaning it with solutions such as alcohol or acetone.

[0047] The post-processing steps after high-speed laser cladding include treating the titanium alloy coating on the substrate surface, i.e., removing rough areas from the cladding surface by grinding, milling, etc., to obtain a bright and clean titanium alloy coating surface.

[0048] In the S3 process, the protective gas is Ar. In this invention, the protective gas cannot be nitrogen. If the protective gas is nitrogen, it will react with the titanium in the raw material.

[0049] In this embodiment of the invention, a high-energy-density laser beam is used as a heat source. The mixed powder is fed into the laser beam and heated to the point of melting on the substrate surface. This ensures that most of the laser energy acts on the mixed powder to ensure its complete melting. This controls the decomposition of some cubic boron nitride ceramic particles and the melting of the nickel plating on their surface. Subsequently, the substrate phase reacts in situ with the partially decomposed cubic boron nitride ceramic particles and the molten nickel plating to generate TiNi, TiB, and Ti2Ni hard phases, which greatly ensures the hardness and wear resistance of the titanium alloy coating.

[0050] In addition, the optimized high-speed laser cladding process suppresses the decomposition of the lubricating phase and regulates its distribution (uniform dispersion), effectively reducing the impact of conventional coating preparation methods on the lubricating phase. Consequently, it does not affect the friction-reducing performance of the lubricating phase, thus effectively improving the friction-reducing performance of the titanium alloy coating.

[0051] Preferably, the average thickness of the nickel layer on the surface of the nickel-coated cubic boron nitride ceramic particles is 1 μm-5 μm.

[0052] Specifically, in this invention, the reinforcing phase is nickel-coated cubic boron nitride ceramic particles. On the one hand, the synergistic effect of dispersion strengthening from the nickel plating and solid solution strengthening from the reinforcing ceramic particles significantly improves the wear resistance of the wear-resistant and friction-reducing titanium alloy coating, greatly increasing its hardness and wear resistance. On the other hand, because individual cubic boron nitride ceramic particles have low density and poor aggregation, they are easily blown away by the powder-feeding gas during high-speed laser cladding, resulting in a reduction in their content in the coating. This invention increases the specific gravity of the cubic boron nitride ceramic particles and improves the lamination efficiency of the reinforcing phase by coating the surface of the cubic boron nitride ceramic particles with a nickel plating layer.

[0053] Furthermore, the average thickness of the nickel plating layer is preferably 3 μm. If the nickel plating layer is too thin, the specific gravity of the cubic boron nitride ceramic particles will still be low, thus failing to effectively improve the lamination efficiency of the reinforcing phase cubic boron nitride ceramic particles. If the nickel plating layer is too thick, the content of cubic boron nitride ceramic particles will be low, resulting in the wear resistance of the wear-resistant and friction-reducing titanium alloy coating not being significantly improved, and consequently failing to increase the hardness and wear resistance of the titanium alloy coating. If the average thickness of the nickel plating layer is 3 μm, the content of cubic boron nitride ceramic particles (compared to a thickness of 5 μm or more) is higher, thereby enabling the in-situ generation of more TiNi and TiB hard phases, which greatly improves the hardness and wear resistance of the wear-resistant and friction-reducing titanium alloy coating. Moreover, compared to the Ti2Ni hard phase, the higher the content of TiNi and TiB hard phases, the better the wear resistance of the wear-resistant and friction-reducing titanium alloy coating will be improved. Therefore, the thickness of the nickel plating layer should not be too thick.

[0054] Preferably, the titanium alloy matrix is ​​TC11 high-temperature titanium alloy.

[0055] Specifically, the compressor blades are made of high-temperature titanium alloy, such as TC11 high-temperature titanium alloy.

[0056] Preferably, the titanium alloy substrate and the wear-resistant and friction-reducing titanium alloy coating are metallurgically bonded.

[0057] Specifically, by employing a high-speed laser cladding coating preparation method and adjusting the process parameters of high-speed laser cladding, a metallurgical bond is achieved between the titanium alloy coating and the substrate, with an element transition zone of less than 50 μm.

[0058] In this invention, when high-speed laser cladding is used, most of the laser energy acts on the mixed powder to ensure its complete melting, while the remaining small portion of the laser energy acts on the substrate to form a molten pool, reducing the thermal impact on the substrate. This energy distribution causes less thermal damage to the substrate. Simultaneously, with the high-speed movement of the substrate, a functional coating that is metallurgically bonded to the substrate can be efficiently prepared, resulting in a high-quality and high-performance functional coating. It should be noted that without adjusting the process parameters, the metallurgical bonding effect cannot be achieved.

[0059] Because high-speed laser cladding is used, the laser beam melts the mixed powder (decomposition and in-situ reaction occur during melting), and the melted powder is directly deposited on the substrate surface to obtain a wear-resistant and friction-reducing titanium alloy coating. During the high-speed laser cladding process, a portion of the laser beam's energy is absorbed by the substrate, melting it and creating an elemental transition zone (the area where the substrate is melted) between the wear-resistant and friction-reducing titanium alloy coating and the substrate. This elemental transition zone needs to be less than 50 μm, resulting in a relatively low dilution rate of the wear-resistant and friction-reducing titanium alloy coating by the substrate, which maximizes the self-lubricating and wear-resistant properties of the coating. It should be noted that if the dilution effect of the substrate on the wear-resistant and friction-reducing titanium alloy coating is too large, the performance of the coating will be poor.

[0060] Preferably, in the mixed powder, the mass fraction of the lubricating phase raw material is 1-25 wt.%, the mass fraction of the reinforcing phase raw material is 20-40 wt.%, and the remainder is the mass fraction of the matrix phase raw material; the sum of the mass fractions of the lubricating phase raw material, the reinforcing phase raw material, and the matrix phase raw material is 100%.

[0061] Preferably, the process parameters for the high-speed laser cladding are: laser power 1.5kW-2.5kW, cladding rate 100mm / s-300mm / s, protective gas flow rate 1L / min-5L / min, and overlap rate 50-80%.

[0062] Furthermore, the cladding rate (scanning speed) is preferably 300 mm / s, and the flow rate is preferably 1 L / min-2 L / min.

[0063] Specifically, by employing a high-speed laser cladding coating preparation method and controlling the process parameters of high-speed laser cladding, a metallurgical bond is achieved between the wear-resistant and friction-reducing titanium alloy coating and the substrate. Furthermore, by adjusting the process parameters, the components are uniformly dispersed in the wear-resistant and friction-reducing titanium alloy coating after cladding. Because the B and N atoms released during decomposition, as well as the undecomposed cubic boron nitride ceramic particles, have a low specific gravity, they may slightly float during the laser cladding process. This results in uneven distribution of the TiNi and TiB hard phases in the wear-resistant and friction-reducing titanium alloy coating. Furthermore, nickel enters the uneven TiNi and TiB lattice, failing to uniformly achieve the solid solution strengthening effect. Consequently, the overall hardness and wear resistance of the wear-resistant and friction-reducing titanium alloy coating are uneven, thus affecting the coating's service performance.

[0064] The present invention also provides an application of the wear-resistant and friction-reducing titanium alloy coating as a protective coating for high-pressure compressor blades.

[0065] The wear-resistant and friction-reducing titanium alloy coating provided in this embodiment of the invention is a coating for compressor blades and cannot be used as a coating for high-speed aero engines, high-temperature bearings, turbine bearings (with service temperatures of extreme temperatures, such as 900℃-1100℃).

[0066] Since compressor blades inevitably experience wear under high-speed operating conditions, this invention protects them by applying a wear-resistant and friction-reducing titanium alloy coating to the blade tip surface, allowing the compressor blades to operate under high-speed conditions and alternating hot and cold cycles. Furthermore, the technical solution provided by this invention is direct and rapid. It should also be noted that the titanium alloy coating matrix phase in this invention uses a high-temperature titanium alloy, ensuring good compatibility between the titanium alloy coating and the substrate (blade). In addition, the lubricating phase in this invention cannot be graphite, nickel-coated graphite, tungsten disulfide, MoS2, etc., mainly because graphite, nickel-coated graphite, tungsten disulfide, MoS2, etc., have low decomposition temperatures and cannot withstand the large amount of heat input during the ultra-high-speed laser cladding coating preparation process. They are prone to decomposition during coating preparation, failing to guarantee a good friction-reducing and lubricating effect (for example, graphite decomposes at 300℃, tungsten disulfide at 400℃, and MoS2 at 300℃).

[0067] To enable those skilled in the art to better understand the present invention, the preparation method provided by the present invention will be described below through several specific embodiments.

[0068] Example 1

[0069] First, the lubricating phase material (silver), the reinforcing phase material (nickel-coated cubic boron nitride ceramic particles), and the matrix phase material (Ti60 high-temperature titanium alloy powder) were weighed according to a mass fraction of 1:3:6. The average thickness of the nickel plating layer was 3 μm. The surface and cross-section of the nickel-coated cubic boron nitride ceramic particles are shown below. Figure 1 (a) and Figure 1 As shown in (b) Figure 1 (b) The white-gray color is the nickel plating layer.

[0070] The matrix phase raw material and the lubricating phase raw material were ball-milled at a ball-to-material ratio of 5:1, with a ball mill speed of 300 r / min and a ball milling time of 3 h. After sieving, the composite powder of the lubricating phase and the matrix phase was obtained. The composite powder was then mechanically mixed with the weighed reinforcing phase raw material (nickel-coated cubic boron nitride ceramic particles) to obtain a mixed powder. The ball mill speed was 200 r / min and the ball milling time was 1 h to ensure uniform mixing of the raw materials.

[0071] The obtained mixed powder was used to prepare a titanium alloy coating on the surface of a TC11 high-temperature titanium alloy substrate using a high-speed laser cladding process. The process parameters for high-speed laser cladding were: laser power 2 kW, cladding rate (scanning speed) 100 mm / s, protective gas flow rate 2 L / min, and overlap rate 70%. The titanium alloy coating consisted of a matrix phase, a reinforcing phase, and a lubricating phase (the volume fraction of cubic boron nitride ceramic particles in the reinforcing phase was 20%, and the volume fraction of the lubricating phase was 10%). The matrix phase was Ti60 high-temperature titanium alloy with a particle size range of 50 μm-90 μm; the reinforcing phase consisted of hard phases (TiN, TiB, and Ti2Ni) and cubic boron nitride ceramic particles with a particle size range of 20 μm-30 μm; and the lubricating phase was silver (Ag) with a particle size range of 1 μm-5 μm.

[0072] The cross-sectional macroscopic morphology and XRD pattern of the Ti60-cBN-Ag titanium alloy coating obtained in this embodiment are shown below. Figure 2 (a) and Figure 2 As shown in (b), the coating has a good macroscopic morphology, with no pores or cracks. In addition to the original α-Ti, β-Ti, c-BN and BaF2, TiN, TiB and Ti2Ni hard phases are generated at the reduction sites. The remaining undecomposed cubic boron nitride ceramic particles with a content of 15% are uniformly dispersed in the coating. The lubricating phase and the hard phase are also uniformly dispersed in the coating. Therefore, while ensuring the wear resistance of the coating, a good friction reduction effect can be achieved.

[0073] Example 2

[0074] First, the lubricating phase material (hexagonal boron nitride), the reinforcing phase material (nickel-coated cubic boron nitride ceramic particles), and the matrix phase material (Ti60 high-temperature titanium alloy powder) were weighed according to a mass fraction of 1:3:6. The average thickness of the nickel plating layer was 3 μm. The surface and cross-section of the nickel-coated cubic boron nitride ceramic particles are shown below. Figure 1 (a) and Figure 1 As shown in (b) Figure 1 (b) The white-gray color is the nickel plating layer.

[0075] The matrix phase raw material and the lubricating phase raw material were mechanically ball-milled at a ball-to-material ratio of 5:1, with a ball mill speed of 300 r / min and a ball milling time of 3 h. After sieving, the composite powder of the lubricating phase and the matrix phase was obtained. The composite powder was then mechanically mixed with the weighed reinforcing phase raw material (nickel-coated cubic boron nitride ceramic particles) to obtain a mixed powder. The ball mill speed was 200 r / min and the ball milling time was 1 h to ensure uniform mixing of the raw materials.

[0076] The obtained mixed powder was used to prepare a titanium alloy coating on the surface of a TC11 high-temperature titanium alloy substrate using a high-speed laser cladding process. The process parameters for high-speed laser cladding were: laser power 2.5 kW, cladding rate 200 mm / s, protective gas flow rate 3 L / min, and overlap rate 80%. The titanium alloy coating consisted of a matrix phase, a reinforcing phase, and a lubricating phase (the volume fraction of cubic boron nitride ceramic particles in the reinforcing phase was 15%, and the volume fraction of the lubricating phase was 5%). The matrix phase was Ti60 high-temperature titanium alloy with a particle size range of 50 μm-90 μm. The reinforcing phase consisted of hard phases (TiN, TiB, and Ti2Ni) and cubic boron nitride ceramic particles with a particle size range of 20 μm-30 μm. The lubricating phase was hexagonal boron nitride (h-BN) with a silver particle size range of 2 μm-10 μm.

[0077] The cross-sectional macroscopic morphology and XRD pattern of the Ti60-cBN-hBN titanium alloy coating obtained in this embodiment are shown below. Figure 3 (a) and Figure 3 As shown in (b), the coating has a good macroscopic morphology, with no pores or cracks. In addition to the original α-Ti, β-Ti, c-BN and BaF2, TiN, TiB and Ti2Ni hard phases are generated at the reduction sites. The remaining undecomposed cubic boron nitride ceramic particles are uniformly dispersed inside the coating. The lubricating phase and the hard phase are also uniformly dispersed inside the coating. Therefore, while ensuring the wear resistance of the coating, a good friction reduction effect can be achieved.

[0078] Example 3

[0079] First, the lubricating phase material (barium fluoride), the reinforcing phase material (nickel-coated cubic boron nitride ceramic particles), and the matrix phase material (Ti60 high-temperature titanium alloy powder) were weighed according to a mass fraction of 1:3:6. The average thickness of the nickel plating layer was 3 μm. The surface and cross-section of the nickel-coated cubic boron nitride ceramic particles are shown below. Figure 1 (a) and Figure 1 As shown in (b) Figure 1 (b) The white-gray color is the nickel plating layer.

[0080] The matrix phase raw material and the lubricating phase raw material were mechanically ball-milled at a ball-to-material ratio of 5:1, with a ball mill speed of 300 r / min and a ball milling time of 3 h. After sieving, the composite powder of the lubricating phase and the matrix phase was obtained. The composite powder was then mechanically mixed with the weighed reinforcing phase raw material (nickel-coated cubic boron nitride ceramic particles) to obtain a mixed powder. The ball mill speed was 200 r / min and the ball milling time was 1 h to ensure uniform mixing of the raw materials.

[0081] The obtained mixed powder was used to prepare a titanium alloy coating on the surface of a TC11 high-temperature titanium alloy substrate using a high-speed laser cladding process. The process parameters for high-speed laser cladding were: laser power 2 kW, cladding rate 200 mm / s, protective gas flow rate 3 L / min, and overlap rate 60%. The titanium alloy coating consisted of a matrix phase, a reinforcing phase, and a lubricating phase (the volume fraction of cubic boron nitride ceramic particles in the reinforcing phase was 10%, and the volume fraction of the lubricating phase was 3%). The matrix phase was high-temperature titanium alloy with a particle size range of 50 μm-90 μm. The reinforcing phase consisted of hard phases (TiN, TiB, and Ti2Ni) and cubic boron nitride ceramic particles with a particle size range of 20 μm-30 μm. The lubricating phase was barium fluoride (BaF2) with a particle size range of 3-15 μm.

[0082] The cross-sectional macroscopic morphology and XRD pattern of the Ti60-cBN-BaF2 titanium alloy coating obtained in this embodiment are shown below. Figure 4 (a) and Figure 4 As shown in (b), the coating has a good macroscopic morphology, with no pores or cracks. In addition to the original α-Ti, β-Ti, c-BN and BaF2, hard phases such as TiN, TiB and Ti2Ni are generated at the reduction sites. The remaining undecomposed cubic boron nitride ceramic particles are uniformly dispersed inside the coating. The lubricating phase and hard phase are also uniformly dispersed inside the coating. Therefore, while ensuring the wear resistance of the coating, a good friction reduction effect can be achieved.

[0083] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.

[0086] The above provides a detailed description of a wear-resistant and friction-reducing titanium alloy coating and its preparation method provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A wear reducing and friction reducing titanium alloy coating consisting of a matrix phase, a reinforcing phase and a lubricating phase, characterized in that, The matrix phase is a titanium alloy; The lubricating phase is one of three types: silver, hexagonal boron nitride, and barium fluoride. The reinforcing phase is a combination of cubic boron nitride ceramic particles and a hard phase; the hard phase is TiN, TiB, and Ti2Ni. The cubic boron nitride ceramic particles in the reinforcing phase have a volume fraction of 5-20% and a particle size distribution of 1 μm-40 μm in the wear-resistant and friction-reducing titanium alloy coating.

2. The wear reducing, friction reducing titanium alloy coating of claim 1, wherein, The lubricating phase in the wear-resistant and friction-reducing titanium alloy coating has a volume fraction of 0.1-10% and a particle size distribution of 0.1 μm-20 μm.

3. The wear reducing, friction reducing titanium alloy coating of claim 1, wherein, The lubricating phase, the cubic boron nitride ceramic particles, and the hard phase are uniformly dispersed in the wear-resistant and friction-reducing titanium alloy coating.

4. A method of producing a wear reducing, friction reducing titanium alloy coating as claimed in any one of claims 1 to 3, characterised in that, The preparation method includes: S1, the matrix phase material and the lubricating phase material are mixed in a certain proportion and then ball-milled to obtain composite powder; wherein, the matrix phase material is titanium alloy powder and the lubricating phase material is one of silver, hexagonal boron nitride and barium fluoride powder. S2, the composite powder and the reinforcing phase raw material are mixed mechanically according to the specified ratio to obtain a mixed powder; wherein, the reinforcing phase raw material is nickel-coated cubic boron nitride ceramic particles; S3, the mixed powder is clad onto the surface of a titanium alloy substrate using a high-speed laser to prepare a wear-resistant and friction-reducing titanium alloy coating; wherein, during the high-speed laser cladding process, the nickel-coated cubic boron nitride ceramic particles react in situ with the titanium alloy powder to generate a hard phase, the hard phase being TiN, TiB and Ti2Ni. The average thickness of the nickel layer on the surface of the nickel-coated cubic boron nitride ceramic particles is 1 μm-5 μm; The process parameters for the high-speed laser cladding are: laser power 1.5 kW-2.5 kW, cladding rate 100 mm / s-300 mm / s, protective gas flow rate 1 L / min-5 L / min, and overlap rate 50-80%.

5. The preparation method according to claim 4, characterized in that, The titanium alloy matrix is ​​TC11 high-temperature titanium alloy.

6. The preparation method according to claim 4, characterized in that, The titanium alloy substrate and the wear-resistant and friction-reducing titanium alloy coating are metallurgically bonded.

7. The preparation method according to claim 4, characterized in that, In the mixed powder, the mass fraction of the lubricating phase raw material is 1-25 wt.%, the mass fraction of the reinforcing phase raw material is 20-40 wt.%, and the remainder is the mass fraction of the matrix phase raw material; the sum of the mass fractions of the lubricating phase raw material, the reinforcing phase raw material, and the matrix phase raw material is 100%.

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