Nickel-titanium alloy material and preparation method and application thereof

Abstract

The invention discloses a nickel-titanium alloy material and a preparation method and application thereof. The nickel-titanium alloy material comprises a nickel-titanium alloy body and a TiN-containing coating arranged on the surface of the body, wherein the coating is prepared by adopting a high-power pulse magnetron sputtering technology. The TiN-containing coating in the nickel-titanium alloy material is prepared through the HiPIMS technology, the obtained coating material has the remarkable characteristic of high compactness, and when the coating material is used for an implant material, the nickel element precipitation prevention effect is good. Meanwhile, the nickel-titanium alloy material has the advantages of high corrosion resistance, high binding force, low stress and the like, can be used in (non) implantable medical devices with high corrosion resistance and high compact protection requirements, and is good in application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy materials, and in particular relates to a nickel-titanium alloy material and a preparation method and application thereof. Background Art

[0002] Nickel-titanium alloy has become an ideal material for internal hard tissue repair treatment due to its high strength, low density, good thermal sensitivity and strong corrosion resistance. However, when nickel-titanium alloy is used as an implant, it will bring about the problem of high concentration of nickel element precipitation, which will cause certain toxic damage to lymphocytes, vascular endothelial cells, etc. Therefore, how to solve the problem of nickel element precipitation in nickel-titanium alloy is a key issue faced by the application of nickel-titanium alloy in the biomedical field. At present, coating technology is often used to shield and protect the surface of nickel-titanium alloy to prevent the precipitation of nickel element. However, the density of conventional coatings is low, so the effect of preventing nickel element precipitation is not ideal, which limits the application of nickel-titanium alloy materials to a certain extent. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a nickel-titanium alloy material, which has a high density of the coating on the surface of the material, a good effect of preventing nickel element precipitation, and a good application prospect.

[0004] The invention also provides a method for preparing the nickel-titanium alloy material.

[0005] The present invention also proposes the use of the nickel-titanium alloy material in the preparation of implantable medical devices or medical implant materials.

[0006] The invention also provides a medical material.

[0007] The invention also provides a film coating device for filamentous materials.

[0008] The invention also provides a method for using the film coating device for filamentous materials.

[0009] The invention also provides a method for preparing a nickel-titanium alloy wire surface coating.

[0010] In a first aspect of the present invention, a nickel-titanium alloy material is provided, comprising a nickel-titanium alloy body and a coating containing TiN disposed on the surface of the body, wherein the coating is prepared by adopting a high-power pulsed magnetron sputtering technology.

[0011] The nickel-titanium alloy material according to the embodiment of the present invention has at least the following beneficial effects:

[0012] High Power Impulse Magnetron Sputtering (HiPIMS) technology combines DC magnetron sputtering technology with pulse power technology and is a new type of magnetron sputtering technology with discharge characteristics such as low discharge frequency, low duty cycle, and relatively high peak current density. TiN has excellent biocompatibility. The nickel-titanium alloy material of the present invention contains a TiN coating prepared by using HiPIMS technology. The obtained coating material has the characteristics of significant high density and low roughness, and has a good effect of preventing the precipitation of nickel elements when used as an implant material. At the same time, the nickel-titanium alloy material of the present invention has many advantages such as high corrosion resistance, high bonding strength, and low stress, and can be used in (non)-implantable medical devices with high corrosion resistance and high-density protection requirements, and has good application prospects.

[0013] In some embodiments of the present invention, the nickel-titanium alloy body is a nickel-titanium alloy wire.

[0014] Generally, in the related art, PIII (Plasma Immersion Ion Implantation) technology is used to coat the surface of alloy materials. PIII technology is a surface modification technology that injects accelerated ions in the plasma as dopants into a suitable substrate or a target of a semiconductor chip with an electrode by applying a high-voltage pulsed DC or pure DC power supply. Although PIII technology has a certain shielding effect on bulk memory alloys, for filamentous memory alloys, especially nickel-titanium memory alloys with a diameter in the micron range (such as a diameter of 20 - 200 μm), this technology is not applicable. Because for filamentous memory alloys, the surface memory failure depth needs to be less than 0.5‰ (calculated based on a diameter of 20 - 200 μm, the surface memory failure depth is 1 - 10 nm), while in PIII technology, the Ni element in a certain surface depth will be reduced to about 15% (Ti x Ni 1-x The range of the shape memory effect of the alloy is 0.476 < x < 0.531), and the generated memory failure region is about 60 nm (calculated based on a diameter of 20 - 200 μm), which is much larger than 1 - 10 nm. Therefore, PIII technology is not applicable to the shielding protection of filamentous nickel-titanium memory alloys.

[0015] In the present invention, by using HiPIMS technology to prepare a coating on the nickel-titanium alloy wire, the surface memory failure depth of the alloy wire can be made less than 0.5‰. For example, calculated based on an alloy wire diameter of 20 - 200 μm, the surface memory failure depth is within 10 nm, and the shape memory performance of the prepared nickel-titanium alloy material is better.

[0016] In some embodiments of the present invention, the diameter of the nickel-titanium alloy wire is 1 to 300 μm, such as 20 to 200 μm. The cross-section of the nickel-titanium alloy wire is not limited to a circle, but can also be an ellipse, a fan, a regular or irregular polygon, or other geometric shapes. The diameter of the nickel-titanium alloy wire, unless otherwise specified, refers to the diameter of the circumscribed circle of the cross-sectional shape of the nickel-titanium alloy wire.

[0017] The length of the nickel-titanium alloy wire is not limited, and the specific length can be selected according to needs.

[0018] In some embodiments of the present invention, the thickness of the coating is 5 to 100 nm, such as 10 to 30 nm.

[0019] In some embodiments of the present invention, the coating layer comprises a TiN layer. Optionally, the TiN layer is a nanolayer.

[0020] In some embodiments of the present invention, the coating further comprises a Ti layer. Optionally, the Ti layer is a nanolayer.

[0021] The present invention uses HiPIMS technology and TiN / Ti nano-multilayer shielding coating technology (coating interface stress regulation technology). The former can improve the density and wear resistance of the obtained coating and reduce the roughness of the coating. The latter can regulate the internal stress of the coating, improve the corrosion resistance and bonding strength of the coating, and can achieve effective regulation of the internal stress of the coating. The obtained nickel-titanium alloy material has good performance.

[0022] In some embodiments of the present invention, the Ti layer is located between the TiN layer and the nickel-titanium alloy body.

[0023] In some embodiments of the present invention, the coating comprises Ti layers and TiN layers that are alternately arranged in sequence. Optionally, the nickel-titanium alloy body is adjacent to the Ti layer.

[0024] The present invention adopts a TiN / Ti nano multilayer structure (i.e., Tin / Ti alternating coating), and the periodically added Ti sublayer cyclically interrupts the longitudinal growth of TiN grains, so that TiN is always in an amorphous / ultrafine grain state at the initial nucleation stage, the grain size of the obtained coating becomes smaller, and the coating performance is better.

[0025] In some embodiments of the present invention, the coating comprises Ti layers and TiN layers that are alternately arranged in sequence. Optionally, the nickel-titanium alloy body is adjacent to the Ti layer.

[0026] In some embodiments of the present invention, the thickness of the TiN layer is 0.1-10 nm.

[0027] In some embodiments of the present invention, the thickness of the Ti layer is 0.1-10 nm.

[0028] In some embodiments of the present invention, the TiN layer includes a nano-ultrafine crystal structure.

[0029] In some embodiments of the present invention, the nickel-titanium alloy material also includes an element-injected transition layer, which is an element-injected transition layer formed in the nickel-titanium alloy body by the elements contained in the coating during high-power pulsed magnetron sputtering, and the element-injected transition layer is adjacent to the coating.

[0030] In some embodiments of the present invention, the thickness of the element-implanted transition layer is less than 30 nm, such as 0.01-30 nm, and further 0.1-10 nm.

[0031] In some embodiments of the present invention, the hardness of the coating is above 28 GPa, such as 28 to 40 GPa, and specifically about 31 GPa.

[0032] In some embodiments of the present invention, the wear rate of the coating is 6×10 -6 mm 3 / N·m or less, such as 6×10 -6 mm 3 / N·m~1×10 -6 mm 3 / N·m, specifically, 3.1×10 -6 mm 3 / N·m approximately.

[0033] In some embodiments of the present invention, the surface roughness of the coating is 1.0 to 9.0 nm, such as 1.0 to 5.0 nm, and specifically 3±0.7 nm.

[0034] The second aspect of the present invention provides a method for preparing a nickel-titanium alloy material, comprising the following steps: taking a nickel-titanium alloy body, and preparing a coating containing TiN on the surface of the nickel-titanium alloy body by high-power pulsed magnetron sputtering technology.

[0035] In some embodiments of the present invention, the nickel-titanium alloy body is a nickel-titanium alloy wire.

[0036] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the required target material is selected according to the composition of the target coating.

[0037] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the discharge voltage to the target is 650-750V, such as 700V.

[0038] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the bias voltage is -300V to -800V.

[0039] In the present invention, a certain negative bias voltage is applied to the nickel-titanium alloy wire during high-power pulsed magnetron sputtering so that its Ti injection layer (i.e., element injection transition layer) does not exceed 10 nm, thereby realizing shallow injection technology and obtaining an alloy material with good shape memory properties.

[0040] In some embodiments of the present invention, in the high power pulsed magnetron sputtering technology, the current is 60 to 120A.

[0041] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the appropriate magnetron sputtering time can be adjusted and selected according to the thickness of the target coating.

[0042] In some embodiments of the present invention, in the preparation method, after the nickel-titanium alloy body is ion-cleaned, the coating is prepared by high-power pulsed magnetron sputtering technology. Specifically, the nickel-titanium alloy body (such as nickel-titanium alloy wire) can be ion-cleaned by exciting argon plasma through an ion source to remove pollutants adsorbed on the nickel-titanium alloy body and activate the surface of the nickel-titanium alloy body, which is beneficial to improve the bonding force between the alloy body and the coating such as the TiN layer. Optionally, the ion cleaning includes plasma cleaning.

[0043] The third aspect of the present invention proposes the use of the above-mentioned nickel-titanium alloy material in the preparation of implantable medical devices or medical implant materials.

[0044] The fourth aspect of the present invention provides a medical material comprising the above-mentioned nickel-titanium alloy material.

[0045] In some embodiments of the present invention, the medical material is a medical implant material.

[0046] A fifth aspect of the present invention provides a medical device comprising the above-mentioned nickel-titanium alloy material.

[0047] A sixth aspect of the present invention provides a film coating device for a filamentous material, comprising:

[0048] Rotation system: including an unwinding component for placing the wire-shaped material roll before coating and capable of unwinding the material roll, and a winding component for winding the wire-shaped material after coating;

[0049] Cleaning system: including ion source excitation components;

[0050] The coating system comprises a coating area and a sputtering target arranged in the coating area; the coating method comprises coating by adopting high-power pulsed magnetron sputtering technology.

[0051] In some embodiments of the present invention, the filamentary material comprises nickel titanium alloy wire.

[0052] In some embodiments of the present invention, the coating area includes a first coating chamber that can be used to prepare a Ti layer and a second coating chamber that can be used to prepare a TiN layer.

[0053] In some embodiments of the present invention, the coating area includes a first coating chamber for preparing a Ti layer and a second coating chamber for preparing a TiN layer.

[0054] In some embodiments of the present invention, a plurality of the first coating chambers are provided, and a plurality of the second coating chambers are provided.

[0055] In some embodiments of the present invention, the first coating chamber and the second coating chamber are alternately arranged in the coating area. Optionally, the first coating chamber and the second coating chamber are separate coating chambers to avoid mutual interference between Ti and TiN coating atmospheres, so as to be more conducive to the formation of Ti layer and TiN layer.

[0056] In some embodiments of the present invention, the coating area includes a plurality of coating partitions, and a plurality of first coating cavities and second coating cavities are alternately arranged in the coating partitions. Optionally, a partition screen is used to separate the coating partitions. According to the needs of the target coating, the number of coating partitions and the number and arrangement of the first coating cavities and the second coating cavities in each coating partition can be adaptively adjusted.

[0057] In some embodiments of the present invention, the unwinding component includes an unwinding driving component, which can be used to unwind the wire-shaped material roll before coating. Optionally, the unwinding driving component includes a driving wheel.

[0058] In some embodiments of the present invention, the unwinding component includes an unwinding roller, and the unwinding roller includes a driving wheel. For example, optionally, the unwinding roller is a driving wheel.

[0059] In some embodiments of the present invention, the winding component includes a winding drive component, which can be used to wind up the coated filamentary material. Optionally, the winding drive component includes a driving wheel.

[0060] In some embodiments of the present invention, the winding component includes a winding roller, and the winding roller includes a driving wheel. For example, optionally, the winding roller is a driving wheel.

[0061] In some embodiments of the present invention, the unwinding component further includes: a measuring component 1 for measuring the unwinding rate of the filamentary material roll before coating; the winding component further includes: a measuring component 2 for measuring the winding rate of the filamentary material before and after coating. By measuring the linear speed of the filamentary material at both ends of the winding and unwinding, and adjusting the angular speed of the winding and unwinding component in real time, the speed of the filamentary material at each location is ensured to be the same, and the filamentary material is prevented from being stretched or folded.

[0062] In some embodiments of the present invention, the first measuring component includes a first detection roller, and the second measuring component includes a second detection roller.

[0063] In some embodiments of the present invention, along the conveying direction of the filamentary material before coating, the unwinding component includes an unwinding roller, a first supporting roller, a first detecting roller, and a second supporting roller. The first supporting roller and the second supporting roller can be used to support the filamentary material so that the filamentary material can be smoothly conveyed along the target direction.

[0064] In some embodiments of the present invention, along the conveying direction of the coated filamentary material, the winding component includes a third roller, a second detection roller, a fourth roller and a winding roller. The third roller and the fourth roller can be used to support the filamentary material so that the filamentary material can be smoothly conveyed along the target direction.

[0065] In some embodiments of the present invention, the coating device further includes a cooling system.

[0066] In some embodiments of the present invention, the cooling system comprises a cooling roller.

[0067] In some embodiments of the present invention, a cooling system is provided between the unwinding component and the coating area.

[0068] In some embodiments of the present invention, a cooling system is provided between the winding component and the coating area.

[0069] In some embodiments of the present invention, a cooling system is provided in the coating area. Optionally, there are several cooling systems.

[0070] In some embodiments of the present invention, the cooling system is arranged between adjacent coating partitions.

[0071] In some embodiments of the present invention, the coating area includes a first coating partition and a second coating partition, and a plurality of first coating cavities and second coating cavities are alternately arranged in the first coating partition and the second coating partition respectively; the cooling system is arranged between the first coating partition and the second coating partition.

[0072] In some embodiments of the present invention, a partition screen is used to separate the coating partitions and the membrane partition and the cooling system.

[0073] A seventh aspect of the present invention provides a method for using the above-mentioned film coating device for filamentous materials, characterized in that it comprises the following steps:

[0074] Placing the filamentary material roll in an unwinding component of the rotating system, and moving the filamentary material obtained by unwinding the filamentary material roll into the cleaning system through the unwinding component;

[0075] After the filamentary material is ion cleaned in the cleaning system, it is moved to the coating system for coating.

[0076] In some embodiments of the present invention, in the method of use, after the filamentary material is ion cleaned in the cleaning system, it is moved to the first coating chamber and the second coating chamber in sequence for coating, thereby forming a Ti layer and a TiN layer in sequence on the surface of the filamentary material.

[0077] In some embodiments of the present invention, in the method of use, after ion cleaning, the filamentary material is moved to a plurality of first coating chambers and second coating chambers that are alternately arranged, so that a plurality of Ti layers and TiN layers are alternately formed on the surface of the filamentary material.

[0078] In some embodiments of the present invention, in the method of use, after ion cleaning, the filamentary material is moved in sequence to several coating partitions and a cooling system between each coating partition. After alternating coating and cooling treatments, several Ti layers and TiN layers are alternately formed on the surface of the filamentary material.

[0079] In some embodiments of the present invention, the method of use comprises the following steps:

[0080] S1, the filamentary material roll is placed on the unwinding roller, and the unwinding roller drives the unwinding roller to unwind. The filamentary material passes through the first roller, the first detection roller and the second roller in sequence, and then enters the cleaning system;

[0081] S2, an ion source excitation component in the cleaning system excites to generate ions, and performs ion cleaning on the filamentous material;

[0082] S3, the cleaned filamentary material is cooled by a cooling roller and then enters a coating area for coating;

[0083] S4, the coated filamentary material is cooled by the cooling roller three, and then passes through the support roller three, the detection roller two, and the support roller four in sequence, and then is wound up at the winding roller.

[0084] In some embodiments of the present invention, in step S3, after being cooled by cooling roller one, the filamentary material enters a plurality of first coating cavities and a second coating cavity alternately arranged in the first coating area for coating, and after being cooled by cooling roller two, enters a plurality of first coating cavities and a second coating cavity alternately arranged in the second coating area for coating.

[0085] In an eighth aspect of the present invention, a method for preparing a nickel-titanium alloy wire surface coating is provided, comprising:

[0086] Obtain target HiPIMS discharge parameter data and target coating deposition parameter data of nickel-titanium alloy wire;

[0087] Based on the preset plasma diffusion transport model, the target HiPIMS discharge parameter data and the target coating deposition parameter data, the plasma distribution of the nickel-titanium alloy wire is predicted to obtain the sheath distribution characteristics and the plasma distribution characteristics;

[0088] The nickel-titanium alloy wire is coated based on the sheath distribution characteristics and the plasma distribution characteristics to obtain a target coating.

[0089] Nickel-titanium alloy wire, also known as nickel-titanium memory alloy wire.

[0090] In some embodiments of the present invention, the target HiPIMS discharge parameter data refers to the discharge parameters used in the HiPIMS device for sputtering the TiN layer. It should be noted that the discharge parameters may include parameters such as voltage, duty cycle, frequency, and current, wherein optionally, the voltage may be 700V and the current may be 60 to 120A. The target coating deposition parameter data refers to the deposition parameters during the deposition of the coating on the surface of the nickel-titanium alloy wire. It should be noted that the deposition parameters may include parameters such as deposition rate, gas pressure, and bias voltage, wherein, optionally, the bias voltage may be -300V to -800V.

[0091] It is also necessary to know that the target coating includes a TiN layer. Optionally, the target coating includes a TiN layer and a Ti layer, wherein the TiN layer and the Ti layer are alternately arranged on the surface of the nickel-titanium alloy wire, and the first coating layer in contact with the surface of the nickel-titanium alloy wire is the TiN layer.

[0092] In some embodiments of the present invention, a plasma diffusion transport model for predicting plasma distribution can be constructed by using the Particle-in-cell / Monte Carlo Collision (PIC / MCC) method to simulate the movement of plasma in an electromagnetic field and the collision process between plasmas.

[0093] In some embodiments of the present invention, the present invention can obtain initial coating performance data of nickel-titanium alloy wire under different HiPIMS discharge parameters and deposition parameters through experiments or simulations, and then use the plasma diffusion transport model to predict the distribution of plasma under different parameters. Furthermore, according to the model prediction results, the HiPIMS discharge parameters and deposition parameters are adjusted to optimize the plasma distribution, and then, the actual coating deposition is performed under the adjusted HiPIMS discharge parameters and deposition parameters, thereby obtaining the target coating.

[0094] In some embodiments of the present invention, the step of obtaining target HiPIMS discharge parameter data and target coating deposition parameter data of the nickel-titanium alloy wire includes:

[0095] Obtaining initial HiPIMS discharge parameter data, initial coating deposition parameter data, initial coating microstructure data, and initial coating mechanical property data of nickel-titanium alloy wire;

[0096] Performing parameter control on the initial HiPIMS discharge parameter data to obtain a list of regulated HiPIMS discharge parameter data, and performing parameter control on the initial coating deposition parameter data to obtain a list of regulated coating deposition parameter data, wherein the list of regulated HiPIMS discharge parameter data includes regulated HiPIMS discharge parameter data, and the list of regulated coating deposition parameter data includes regulated coating deposition parameter data;

[0097] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, the initial coating microstructure data is monitored to obtain a follower coating microstructure data list, wherein the follower coating microstructure data list includes the follower coating microstructure data;

[0098] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, the initial coating mechanical property data is monitored to obtain a follow-up coating mechanical property data list, wherein the follow-up coating mechanical property data list includes the follow-up coating mechanical property data;

[0099] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, a mapping function is constructed for the follower coating microstructure data list to obtain a first mapping function, wherein the first mapping function represents a mapping relationship between the HiPIMS discharge parameter data, the coating deposition parameter data and the follower coating microstructure data;

[0100] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, a mapping function is constructed for the follow-up coating mechanical property data list to obtain a second mapping function, wherein the second mapping function represents a mapping relationship between the HiPIMS discharge parameter data, the coating deposition parameter data and the follow-up coating mechanical property data;

[0101] Based on preset target coating microstructure data, preset target coating mechanical property data, the first mapping function and the second mapping function, the target HiPIMS discharge parameter data and the target coating deposition parameter data are determined.

[0102] In some embodiments of the present invention, the initial HiPIMS discharge parameter data refers to the voltage, duty cycle, frequency and other parameters used for sputtering the surface coating of the nickel-titanium alloy wire in the initial state of the HiPIMS device that has not been regulated. The initial coating deposition parameter data refers to the parameters in the deposition process of the nickel-titanium alloy wire surface coating in the initial state, such as deposition rate, gas pressure, bias voltage, etc. The initial coating microstructure data refers to the microstructure such as grain size and phase composition of the nickel-titanium alloy wire surface coating that has not been regulated. The initial coating mechanical property data refers to the mechanical properties such as hardness and elastic modulus of the nickel-titanium alloy wire surface coating that has not been regulated. The list of regulated HiPIMS discharge parameter data refers to a series of HiPIMS discharge parameter data used for HiPIMS discharge after regulation. The list of regulated coating deposition parameter data refers to a series of nickel-titanium alloy wire surface coating deposition parameter data used for nickel-titanium alloy wire surface coating deposition after regulation. The follow-up coating microstructure data list refers to a series of data on the microstructure of the nickel-titanium alloy wire surface coating obtained under the regulated parameters. The dynamic coating mechanical property data list refers to a series of data on the mechanical properties of the nickel-titanium alloy wire surface coating obtained under the control parameters. The preset target coating microstructure data and the preset target coating mechanical property data are the performance data of the preset target coating.

[0103] In some embodiments of the present invention, the microstructure and mechanical property data of the nickel-titanium alloy wire surface coating under the initial HiPIMS discharge parameters and deposition parameters can be collected, and then the HiPIMS discharge parameters and deposition parameters can be adjusted by experiments or simulations, and the coating performance under each set of parameters can be recorded. Furthermore, under each set of adjustment parameters, the microstructure and mechanical property data of the nickel-titanium alloy wire surface coating can be monitored and recorded. Secondly, the collected data can be used to construct a mapping function to reveal the mathematical relationship between the parameters and the coating performance. Finally, according to the preset performance goals, the required HiPIMS discharge parameters and deposition parameters can be determined using the mapping function.

[0104] Optionally, after obtaining the sheath distribution characteristics and plasma distribution characteristics, high-power pulsed magnetron sputtering (HiPIMS) technology can be used to form highly ionized TiN or Ti plasma, and then combined with immersion plasma injection technology, the nickel-titanium alloy wire is immersed in the TiN or Ti plasma, and then, SRIM (Stopping and Range of Ions in Matter) simulation calculation is used to accurately control the formation of the TiN layer or Ti layer. At the same time, the present invention can control the thickness of the formed TiN layer or Ti layer by applying a certain negative bias voltage and a certain current to the nickel-titanium alloy wire within a certain period of time, so that the thickness of the TiN layer is between 10-30nm, and the thickness of the Ti layer does not exceed 10nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0106] Figure 1 A schematic structural diagram of a coating device for preparing a filamentous nickel-titanium alloy material according to an embodiment of the present invention;

[0107] Figure 2 The cross-sectional morphology of the TiN layer of the filamentous nickel-titanium alloy material in Comparative Example 1 Figure 1 ;

[0108] Figure 3 The cross-sectional morphology of the TiN layer of the filamentous nickel-titanium alloy material in Example 1 of the present invention Figure 1 ;

[0109] Figure 4 This is a comparison chart of the hardness test results of the filamentous nickel-titanium alloy material in Example 1 of the present invention and Comparative Example 1;

[0110] Figure 5 The cross-sectional morphology of the TiN layer of the filamentous nickel-titanium alloy material in Comparative Example 1 Figure 2 ;

[0111] Figure 6 The cross-sectional morphology of the TiN layer of the filamentous nickel-titanium alloy material in Example 1 of the present invention Figure 2 ;

[0112] Figure 7 This is a graph showing the surface roughness test results of the TiN coating of the filamentous nickel-titanium alloy material in Comparative Example 1;

[0113] Figure 8 This is a graph showing the surface roughness test results of the TiN coating of the filamentous nickel-titanium alloy material in Example 1 of the present invention;

[0114] Fig. 9 A schematic diagram illustrating the process of preparing a TiN coating using the PIII&D technology in Comparative Example 2;

[0115] Fig.10 Schematic diagram of the process for preparing a TiN coating using HiPIMS technology in Example 1 of the present invention;

[0116] Fig.11 This is a microscopic test result diagram of the filamentous nickel-titanium alloy material of Example 2 of the present invention;

[0117] Fig.12 This is a graph showing the internal stress test results of the filamentary nickel-titanium alloy material of Example 2 of the present invention. DETAILED DESCRIPTION

[0118] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0119] In a first aspect of the present invention, a nickel-titanium alloy material is provided, comprising a nickel-titanium alloy body and a coating containing TiN disposed on the surface of the body, wherein the coating is prepared by adopting a high-power pulsed magnetron sputtering technology.

[0120] The nickel-titanium alloy material according to the embodiment of the present invention has at least the following beneficial effects:

[0121] High-power pulsed magnetron sputtering (HiPIMS) technology combines DC magnetron sputtering technology with pulse power technology. It is a new type of magnetron sputtering technology with discharge characteristics such as low discharge frequency, low duty cycle, and high peak current density. TiN has excellent biocompatibility. The coating containing TiN in the nickel-titanium alloy material of the present invention is prepared by adopting HiPIMS technology. The obtained coating material has the characteristics of significant high density and low roughness. When it is used for implant materials, it has a good effect in preventing nickel element precipitation. At the same time, the nickel-titanium alloy material of the present invention has many advantages such as high corrosion resistance, high bonding force and low stress. It can be used in (non-) implantable medical devices with high corrosion resistance and high density protection requirements, and has good application prospects.

[0122] In some embodiments of the present invention, the nickel-titanium alloy body is a nickel-titanium alloy wire.

[0123] Usually, the PIII (plasma immersion ion implantation) technology is used in the related technology to coat the surface of the alloy material. The PIII technology is a surface modification technology that uses a high-voltage pulsed DC or pure DC power supply to inject the accelerated ions in the plasma as dopants into a suitable substrate or a target of a semiconductor chip with electrodes. Although the PIII technology has a certain shielding effect on bulk memory alloys, this technology is not applicable to filamentary memory alloys, especially nickel-titanium memory alloys with a diameter of micrometer level (such as a diameter of 20 to 200 μm). Because for filamentary memory alloys, the surface memory failure depth needs to be less than 0.5‰ (calculated based on a diameter of 20 to 200 μm, the surface memory failure depth is 1 to 10 nm), and with the PIII technology, the Ni element at a certain depth in the surface layer will be reduced to about 15% (Ti x Ni 1-xThe range of the shape memory effect of the alloy is 0.476 < x < 0.531), and the memory failure region generated is about 60 nm (calculated based on a diameter of 20 - 200 μm), which is much larger than 1 - 10 nm. Therefore, the PIII technology is not applicable to the shielding protection of filamentous NiTi shape memory alloy.

[0124] In the present invention, the HiPIMS technology is used to prepare a coating on the NiTi alloy wire, and the memory failure depth on the surface layer of the alloy wire can be less than 0.5‰. If calculated based on the diameter of the alloy wire being 20 - 200 μm, the memory failure depth on the surface layer is within 10 nm, and the prepared NiTi alloy material has better shape memory performance.

[0125] In some embodiments of the present invention, the diameter of the NiTi alloy wire is 1 - 300 μm, and can be selected as 20 - 200 μm, for example. The cross-section of the NiTi alloy wire is not limited to a circular shape, and can also be various geometric shapes such as an ellipse, a sector, a regular or irregular polygon, etc. Unless otherwise specified, the diameter of the NiTi alloy wire refers to the diameter of the circumscribed circle of the cross-sectional shape of the NiTi alloy wire.

[0126] The length of the NiTi alloy wire is not limited, and specific length dimensions can be selected according to needs.

[0127] In some embodiments of the present invention, the thickness of the coating is 5 - 100 nm, and can be selected as 10 - 30 nm, for example.

[0128] In some embodiments of the present invention, the coating includes a TiN layer. Optionally, the TiN layer is a nano-layer.

[0129] In some embodiments of the present invention, the coating further includes a Ti layer. Optionally, the Ti layer is a nano-layer.

[0130] In the present invention, the HiPIMS technology and the TiN / Ti nano-multilayer shielding coating technology (coating interface stress regulation technology) are used. The former can improve the density, wear resistance of the obtained coating and reduce the roughness of the coating, and the latter can regulate the internal stress in the coating, improve the corrosion resistance and adhesion of the coating, and can effectively regulate the internal stress in the coating, and the obtained NiTi alloy material has good performance.

[0131] In some embodiments of the present invention, the Ti layer is located between the TiN layer and the NiTi alloy body.

[0132] In some embodiments of the present invention, the coating includes alternately arranged Ti layers and TiN layers. Optionally, the NiTi alloy body is adjacent to the Ti layer.

[0133] The present invention adopts a TiN / Ti nano multilayer structure (i.e., Tin / Ti alternating coating), and the periodically added Ti sublayer cyclically interrupts the longitudinal growth of TiN grains, so that TiN is always in an amorphous / ultrafine grain state at the initial nucleation stage, the grain size of the obtained coating becomes smaller, and the coating performance is better.

[0134] In some embodiments of the present invention, the coating layer comprises Ti layers and TiN layers which are alternately arranged in sequence. The nickel-titanium alloy body is adjacent to the Ti layers.

[0135] In some embodiments of the present invention, the thickness of the TiN layer is 0.1-10 nm.

[0136] In some embodiments of the present invention, the thickness of the Ti layer is 0.1-10 nm.

[0137] In some embodiments of the present invention, the TiN layer includes a nano-ultrafine crystal structure.

[0138] In some embodiments of the present invention, the nickel-titanium alloy material also includes an element-injected transition layer, which is an element-injected transition layer formed in the nickel-titanium alloy body by the elements contained in the coating during high-power pulsed magnetron sputtering, and the element-injected transition layer is adjacent to the coating.

[0139] In some embodiments of the present invention, the thickness of the element-implanted transition layer is less than 30 nm, such as 0.01-30 nm, and further 0.1-10 nm.

[0140] In some embodiments of the present invention, the hardness of the coating is above 28 GPa, such as 28 to 40 GPa, and specifically about 31 GPa.

[0141] In some embodiments of the present invention, the wear rate of the coating is 6×10 -6 mm 3 / N·m or less, such as 6×10 -6 mm 3 / N·m~1×10 -6 mm 3 / N·m, specifically, 3.1×10 -6 mm 3 / N·m approximately.

[0142] In some embodiments of the present invention, the surface roughness of the coating is 1.0 to 9.0 nm, such as 1.0 to 5.0 nm, and specifically 3±0.7 nm.

[0143] The second aspect of the present invention provides a method for preparing a nickel-titanium alloy material, comprising the following steps: taking a nickel-titanium alloy body, and preparing a coating containing TiN on the surface of the nickel-titanium alloy body by high-power pulsed magnetron sputtering technology.

[0144] In some embodiments of the present invention, the nickel-titanium alloy body is a nickel-titanium alloy wire.

[0145] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the required target material is selected according to the composition of the target coating.

[0146] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the discharge voltage to the target is 650-750V, such as 700V.

[0147] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the bias voltage is -300V to -800V.

[0148] In the present invention, a certain negative bias voltage is applied to the nickel-titanium alloy wire during high-power pulsed magnetron sputtering so that its Ti injection layer (i.e., element injection transition layer) does not exceed 10 nm, thereby realizing shallow injection technology and obtaining an alloy material with good shape memory properties.

[0149] In some embodiments of the present invention, in the high power pulsed magnetron sputtering technology, the current is 60 to 120A.

[0150] In some embodiments of the present invention, in the high-power pulsed magnetron sputtering technology, the appropriate magnetron sputtering time can be adjusted and selected according to the thickness of the target coating.

[0151] In some embodiments of the present invention, in the preparation method, after the nickel-titanium alloy body is ion-cleaned, the coating is prepared by high-power pulsed magnetron sputtering technology. Specifically, the nickel-titanium alloy body (such as nickel-titanium alloy wire) can be ion-cleaned by exciting argon plasma through an ion source to remove pollutants adsorbed on the nickel-titanium alloy body and activate the surface of the nickel-titanium alloy body, which is beneficial to improve the bonding force between the alloy body and the coating such as the TiN layer. Optionally, the ion cleaning includes plasma cleaning.

[0152] The third aspect of the present invention proposes the use of the above-mentioned nickel-titanium alloy material in the preparation of implantable medical devices or medical implant materials.

[0153] The fourth aspect of the present invention provides a medical material comprising the above-mentioned nickel-titanium alloy material.

[0154] In some embodiments of the present invention, the medical material is a medical implant material.

[0155] A fifth aspect of the present invention provides a medical device comprising the above-mentioned nickel-titanium alloy material.

[0156] A sixth aspect of the present invention provides a film coating device for a filamentous material, comprising:

[0157] Rotation system: including an unwinding component for placing the wire-shaped material roll before coating and capable of unwinding the material roll, and a winding component for winding the wire-shaped material after coating;

[0158] Cleaning system: including ion source excitation components;

[0159] The coating system comprises a coating area and a sputtering target arranged in the coating area; the coating method comprises coating by adopting high-power pulsed magnetron sputtering technology.

[0160] In some embodiments of the present invention, the filamentary material comprises nickel titanium alloy wire.

[0161] In some embodiments of the present invention, the coating area includes a first coating chamber that can be used to prepare a Ti layer and a second coating chamber that can be used to prepare a TiN layer.

[0162] In some embodiments of the present invention, the coating area includes a first coating chamber for preparing a Ti layer and a second coating chamber for preparing a TiN layer.

[0163] In some embodiments of the present invention, a plurality of the first coating chambers are provided, and a plurality of the second coating chambers are provided.

[0164] In some embodiments of the present invention, the first coating chamber and the second coating chamber are alternately arranged in the coating area. Optionally, the first coating chamber and the second coating chamber are separate coating chambers to avoid mutual interference between Ti and TiN coating atmospheres, so as to be more conducive to the formation of Ti layer and TiN layer.

[0165] In some embodiments of the present invention, the coating area includes a plurality of coating partitions, and a plurality of first coating cavities and second coating cavities are alternately arranged in the coating partitions. Optionally, a partition screen is used to separate the coating partitions. According to the needs of the target coating, the number of coating partitions and the number and arrangement of the first coating cavities and the second coating cavities in each coating partition can be adaptively adjusted.

[0166] In some embodiments of the present invention, the unwinding component includes an unwinding driving component, which can be used to unwind the wire-shaped material roll before coating. Optionally, the unwinding driving component includes a driving wheel.

[0167] In some embodiments of the present invention, the unwinding component includes an unwinding roller, and the unwinding roller includes a driving wheel. For example, optionally, the unwinding roller is a driving wheel.

[0168] In some embodiments of the present invention, the winding component includes a winding drive component, which can be used to wind up the coated filamentary material. Optionally, the winding drive component includes a driving wheel.

[0169] In some embodiments of the present invention, the winding component includes a winding roller, and the winding roller includes a driving wheel. For example, optionally, the winding roller is a driving wheel.

[0170] In some embodiments of the present invention, the unwinding component further includes: a measuring component 1 for measuring the unwinding rate of the filamentary material roll before coating; the winding component further includes: a measuring component 2 for measuring the winding rate of the filamentary material before and after coating. By measuring the linear speed of the filamentary material at both ends of the winding and unwinding, and adjusting the angular speed of the winding and unwinding component in real time, the speed of the filamentary material at each location is ensured to be the same, and the filamentary material is prevented from being stretched or folded.

[0171] In some embodiments of the present invention, the first measuring component includes a first detection roller, and the second measuring component includes a second detection roller.

[0172] In some embodiments of the present invention, along the conveying direction of the filamentary material before coating, the unwinding component includes an unwinding roller, a first supporting roller, a first detecting roller, and a second supporting roller. The first supporting roller and the second supporting roller can be used to support the filamentary material so that the filamentary material can be smoothly conveyed along the target direction.

[0173] In some embodiments of the present invention, along the conveying direction of the coated filamentary material, the winding component includes a third roller, a second detection roller, a fourth roller and a winding roller. The third roller and the fourth roller can be used to support the filamentary material so that the filamentary material can be smoothly conveyed along the target direction.

[0174] In some embodiments of the present invention, the coating device further includes a cooling system.

[0175] In some embodiments of the present invention, the cooling system comprises a cooling roller.

[0176] In some embodiments of the present invention, a cooling system is provided between the unwinding component and the coating area.

[0177] In some embodiments of the present invention, a cooling system is provided between the winding component and the coating area.

[0178] In some embodiments of the present invention, a cooling system is provided in the coating area. Optionally, there are several cooling systems.

[0179] In some embodiments of the present invention, the cooling system is arranged between adjacent coating partitions.

[0180] In some embodiments of the present invention, the coating area includes a first coating partition and a second coating partition, and a plurality of first coating cavities and second coating cavities are alternately arranged in the first coating partition and the second coating partition respectively; the cooling system is arranged between the first coating partition and the second coating partition.

[0181] In some embodiments of the present invention, a partition screen is used to separate the coating partitions and the membrane partition and the cooling system.

[0182] A seventh aspect of the present invention provides a method for using the above-mentioned film coating device for filamentous materials, characterized in that it comprises the following steps:

[0183] Placing the filamentary material roll in an unwinding component of the rotating system, and moving the filamentary material obtained by unwinding the filamentary material roll into the cleaning system through the unwinding component;

[0184] After the filamentary material is ion cleaned in the cleaning system, it is moved to the coating system for coating.

[0185] In some embodiments of the present invention, in the method of use, after the filamentary material is ion cleaned in the cleaning system, it is moved to the first coating chamber and the second coating chamber in sequence for coating, thereby forming a Ti layer and a TiN layer in sequence on the surface of the filamentary material.

[0186] In some embodiments of the present invention, in the method of use, after ion cleaning, the filamentary material is moved to a plurality of first coating chambers and second coating chambers that are alternately arranged, so that a plurality of Ti layers and TiN layers are alternately formed on the surface of the filamentary material.

[0187] In some embodiments of the present invention, in the method of use, after ion cleaning, the filamentary material is moved in sequence to several coating partitions and a cooling system between each coating partition. After alternating coating and cooling treatments, several Ti layers and TiN layers are alternately formed on the surface of the filamentary material.

[0188] In some embodiments of the present invention, the method of use comprises the following steps:

[0189] S1, the filamentary material roll is placed on the unwinding roller, and the unwinding roller drives the unwinding roller to unwind. The filamentary material passes through the first roller, the first detection roller and the second roller in sequence, and then enters the cleaning system;

[0190] S2, an ion source excitation component in the cleaning system excites to generate ions, and performs ion cleaning on the filamentous material;

[0191] S3, the cleaned filamentary material is cooled by a cooling roller and then enters a coating area for coating;

[0192] S4, the coated filamentary material is cooled by the cooling roller three, and then passes through the support roller three, the detection roller two, and the support roller four in sequence, and then is wound up at the winding roller.

[0193] In some embodiments of the present invention, in step S3, after being cooled by cooling roller one, the filamentary material enters a plurality of first coating cavities and a second coating cavity alternately arranged in the first coating area for coating, and after being cooled by cooling roller two, enters a plurality of first coating cavities and a second coating cavity alternately arranged in the second coating area for coating.

[0194] In an eighth aspect of the present invention, a method for preparing a nickel-titanium alloy wire surface coating is provided, comprising:

[0195] Obtain target HiPIMS discharge parameter data and target coating deposition parameter data of nickel-titanium alloy wire;

[0196] Based on the preset plasma diffusion transport model, the target HiPIMS discharge parameter data and the target coating deposition parameter data, the plasma distribution of the nickel-titanium alloy wire is predicted to obtain the sheath distribution characteristics and the plasma distribution characteristics;

[0197] The nickel-titanium alloy wire is coated based on the sheath distribution characteristics and the plasma distribution characteristics to obtain a target coating.

[0198] Nickel-titanium alloy wire, also known as nickel-titanium memory alloy wire.

[0199] In some embodiments of the present invention, the target HiPIMS discharge parameter data refers to the discharge parameters used in the HiPIMS device for sputtering the TiN layer. It should be noted that the discharge parameters may include parameters such as voltage, duty cycle, frequency, and current, wherein optionally, the voltage may be 700V and the current may be 60 to 120A. The target coating deposition parameter data refers to the deposition parameters during the deposition of the coating on the surface of the nickel-titanium alloy wire. It should be noted that the deposition parameters may include parameters such as deposition rate, gas pressure, and bias voltage, wherein, optionally, the bias voltage may be -300V to -800V.

[0200] It is also necessary to know that the target coating includes a TiN layer. Optionally, the target coating includes a TiN layer and a Ti layer, wherein the TiN layer and the Ti layer are alternately arranged on the surface of the nickel-titanium alloy wire, and the first coating layer in contact with the surface of the nickel-titanium alloy wire is the TiN layer.

[0201] In some embodiments of the present invention, a plasma diffusion transport model for predicting plasma distribution can be constructed by using the Particle-in-cell / Monte Carlo Collision (PIC / MCC) method to simulate the movement of plasma in an electromagnetic field and the collision process between plasmas.

[0202] In some embodiments of the present invention, the present invention can obtain initial coating performance data of nickel-titanium alloy wire under different HiPIMS discharge parameters and deposition parameters through experiments or simulations, and then use the plasma diffusion transport model to predict the distribution of plasma under different parameters. Furthermore, according to the model prediction results, the HiPIMS discharge parameters and deposition parameters are adjusted to optimize the plasma distribution, and then, the actual coating deposition is performed under the adjusted HiPIMS discharge parameters and deposition parameters, thereby obtaining the target coating.

[0203] In some embodiments of the present invention, the step of obtaining target HiPIMS discharge parameter data and target coating deposition parameter data of the nickel-titanium alloy wire includes:

[0204] Obtaining initial HiPIMS discharge parameter data, initial coating deposition parameter data, initial coating microstructure data, and initial coating mechanical property data of nickel-titanium alloy wire;

[0205] Performing parameter control on the initial HiPIMS discharge parameter data to obtain a list of regulated HiPIMS discharge parameter data, and performing parameter control on the initial coating deposition parameter data to obtain a list of regulated coating deposition parameter data, wherein the list of regulated HiPIMS discharge parameter data includes regulated HiPIMS discharge parameter data, and the list of regulated coating deposition parameter data includes regulated coating deposition parameter data;

[0206] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, the initial coating microstructure data is monitored to obtain a follower coating microstructure data list, wherein the follower coating microstructure data list includes the follower coating microstructure data;

[0207] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, the initial coating mechanical property data is monitored to obtain a follow-up coating mechanical property data list, wherein the follow-up coating mechanical property data list includes the follow-up coating mechanical property data;

[0208] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, a mapping function is constructed for the follower coating microstructure data list to obtain a first mapping function, wherein the first mapping function represents a mapping relationship between the HiPIMS discharge parameter data, the coating deposition parameter data and the follower coating microstructure data;

[0209] Based on the HiPIMS discharge parameter data list and the coating deposition parameter data list, a mapping function is constructed for the follow-up coating mechanical property data list to obtain a second mapping function, wherein the second mapping function represents a mapping relationship between the HiPIMS discharge parameter data, the coating deposition parameter data and the follow-up coating mechanical property data;

[0210] Based on preset target coating microstructure data, preset target coating mechanical property data, the first mapping function and the second mapping function, the target HiPIMS discharge parameter data and the target coating deposition parameter data are determined.

[0211] In some embodiments of the present invention, the initial HiPIMS discharge parameter data refers to the voltage, duty cycle, frequency and other parameters used for sputtering the surface coating of the nickel-titanium alloy wire in the initial state of the HiPIMS device that has not been regulated. The initial coating deposition parameter data refers to the parameters in the deposition process of the nickel-titanium alloy wire surface coating in the initial state, such as deposition rate, gas pressure, bias voltage, etc. The initial coating microstructure data refers to the microstructure such as grain size and phase composition of the nickel-titanium alloy wire surface coating that has not been regulated. The initial coating mechanical property data refers to the mechanical properties such as hardness and elastic modulus of the nickel-titanium alloy wire surface coating that has not been regulated. The list of regulated HiPIMS discharge parameter data refers to a series of HiPIMS discharge parameter data used for HiPIMS discharge after regulation. The list of regulated coating deposition parameter data refers to a series of nickel-titanium alloy wire surface coating deposition parameter data used for nickel-titanium alloy wire surface coating deposition after regulation. The follow-up coating microstructure data list refers to a series of data on the microstructure of the nickel-titanium alloy wire surface coating obtained under the regulated parameters. The dynamic coating mechanical property data list refers to a series of data on the mechanical properties of the nickel-titanium alloy wire surface coating obtained under the control parameters. The preset target coating microstructure data and the preset target coating mechanical property data are the performance data of the preset target coating.

[0212] In some embodiments of the present invention, the microstructure and mechanical property data of the nickel-titanium alloy wire surface coating under the initial HiPIMS discharge parameters and deposition parameters can be collected, and then the HiPIMS discharge parameters and deposition parameters can be adjusted by experiments or simulations, and the coating performance under each set of parameters can be recorded. Furthermore, under each set of adjustment parameters, the microstructure and mechanical property data of the nickel-titanium alloy wire surface coating can be monitored and recorded. Secondly, the collected data can be used to construct a mapping function to reveal the mathematical relationship between the parameters and the coating performance. Finally, according to the preset performance goals, the required HiPIMS discharge parameters and deposition parameters can be determined using the mapping function.

[0213] Optionally, after obtaining the sheath distribution characteristics and plasma distribution characteristics, high-power pulsed magnetron sputtering (HiPIMS) technology can be used to form highly ionized TiN or Ti plasma, and then combined with immersion plasma injection technology, the nickel-titanium alloy wire is immersed in the TiN or Ti plasma, and then, SRIM (Stopping and Range of Ions in Matter) simulation calculation is used to accurately control the formation of the TiN layer or Ti layer. At the same time, the present invention can control the thickness of the formed TiN layer or Ti layer by applying a certain negative bias voltage and a certain current to the nickel-titanium alloy wire within a certain period of time, so that the thickness of the TiN layer is between 10-30nm, and the thickness of the Ti layer does not exceed 10nm.

[0214] In some embodiments of the present invention, a coating device for preparing a wire-shaped nickel-titanium alloy material is shown in FIG. Figure 1 As shown, it includes a rotation system, a cleaning system, a coating system and a cooling system, wherein:

[0215] The rotation system provides winding and conveying functions. Specifically, the rotation system and its functional description include: the NiTi wire roll is placed on the unwinding roller, the wire head is connected to the metal wire of the same diameter, and is connected to the rewinding roller after passing through the entire coating path. Both the unwinding roller and the rewinding roller are active wheels, and their rotation angular velocity can be adjusted through the control program. A detection rod is set at each of the unwinding end and the rewinding end to measure the linear velocity of the NiTi wire at both ends of the unwinding and rewinding, and the angular velocity of the rewinding roller is adjusted in real time to ensure that the linear velocity of the NiTi wire at each end is the same to avoid the wire being elongated or folded.

[0216] The cleaning system and its functional description include: exciting argon plasma through an ion source to perform ion cleaning on the wire, removing pollutants adsorbed on the wire, and activating the surface of the wire, which is beneficial to improving the bonding force of the TiN coating.

[0217] The coating system and its functional description include: the wire enters the coating area after passing through the partition screen, each pair of sputtering targets are placed vertically face to face, and the wire passes through the middle of a pair of sputtering targets to ensure the uniformity of the coating in the circumferential direction of the wire. Each pair of sputtering targets is supplied with gas separately, and different functional areas are formed for different purposes of Ti or TiN coating. Each functional area is also separated by a partition screen to avoid mutual interference between Ti and TiN coating atmospheres. The number of repetitions of Ti / TiN multilayer film can be set according to the previous basic research.

[0218] The cold cutting system and its functional description include: To prevent the wire from overheating during the coating process, the equipment is equipped with three cooling rollers, which are located after ion cleaning, in the middle of the coating process, and after coating.

[0219] The experimental methods without specific conditions in the following examples and comparative examples are generally based on conventional conditions in the art or conditions recommended by the manufacturers; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents available from commercial channels such as conventional markets.

[0220] Example 1

[0221] This embodiment discloses a filamentous nickel-titanium alloy material, the preparation process of which includes the following steps:

[0222] (I) taking a NiTi wire coil (with a diameter of 20 to 200 μm), exciting an argon plasma with an ion source, and ion cleaning the NiTi wire to remove pollutants adsorbed on the NiTi wire and activate the surface of the NiTi wire, which is beneficial to improving the bonding strength between the alloy body and the coating;

[0223] (II) A TiN layer was prepared on the surface of the NiTi wire using high power pulsed magnetron sputtering (HiPIMS) technology; specific process parameters included: a discharge voltage of 700 V to the target, a bias voltage of -300 V to -800 V, and a current of 60 to 120 A.

[0224] Since a certain negative bias is applied to the NiTi wire, the Ti injection layer does not exceed 10nm and the thickness of the TiN layer is 10-30nm.

[0225] The coating device for preparing the wire-shaped nickel-titanium alloy material in this embodiment includes a rotation system, a cleaning system, a coating system and a cooling system, wherein:

[0226] The rotation system and its functional description include: the NiTi wire roll is placed on the unwinding roller, the wire end is connected to the metal wire of the same diameter, and is connected to the rewinding roller after passing through the entire coating path. Both the unwinding roller and the rewinding roller are active wheels, and their rotation angular velocity can be adjusted through the control program. A detection rod is set at each of the unwinding end and the rewinding end to measure the linear velocity of the NiTi wire at both ends of the unwinding and rewinding, and the angular velocity of the rewinding roller is adjusted in real time to ensure that the linear velocity of the NiTi wire at each end is the same to avoid the wire being elongated or folded.

[0227] The cleaning system and its functional description include: exciting argon plasma through an ion source to perform ion cleaning on the wire, removing pollutants adsorbed on the wire, and activating the surface of the wire, which is beneficial to improving the bonding force of the TiN coating.

[0228] The coating system and its functional description include: the wire enters the coating area after passing through the partition screen, each pair of sputtering targets are arranged vertically face to face, and the wire passes through the middle of a pair of sputtering targets to ensure the uniformity of the coating in the circumferential direction of the wire.

[0229] The cold cutting system and its functional description include: To prevent the wire from overheating during the coating process, the equipment is equipped with two cooling rollers, one after ion cleaning and the other after coating.

[0230] Example 2

[0231] This embodiment discloses a filamentous nickel-titanium alloy material, the preparation process of which includes the following steps:

[0232] (I) taking a NiTi wire coil, exciting an argon plasma with an ion source, and ion cleaning the NiTi wire to remove pollutants adsorbed on the NiTi wire and activate the surface of the NiTi wire, which is beneficial to improving the bonding strength between the alloy body and the coating;

[0233] (II) Ti and TiN layers were alternately prepared on the surface of NiTi wire using high-power pulsed magnetron sputtering technology;

[0234] The specific process parameters for preparing the Ti layer include: the discharge voltage to the target is 700V, the bias voltage is -300V to -800V, and the current is 60 to 120A;

[0235] The specific process parameters for preparing the TiN layer include: a discharge voltage of 700V to the target, a bias voltage of -300V to -800V, and a current of 60 to 120A.

[0236] Since a certain negative bias is applied to the NiTi wire, the Ti injection layer does not exceed 10nm, and the total coating thickness is 10-30nm.

[0237] This embodiment is used to prepare a coating device for a wire-shaped nickel-titanium alloy material (see the schematic diagram of the structure for Figure 1 ), including a rotation system, a cleaning system, a coating system and a cooling system, wherein the coating device in Example 1 is different from the coating device in Example 1 in that:

[0238] In the coating system, each pair of sputtering targets is supplied with gas separately, and different functional areas are formed according to the different purposes of Ti or TiN coating. Each functional area is also separated by a partition screen to avoid mutual interference between the Ti coating and TiN coating atmospheres.

[0239] The cold cutting system and its functional description include: To prevent the wire from overheating during the coating process, the equipment is equipped with three cooling rollers, which are located after ion cleaning, in the middle of the coating process, and after coating.

[0240] Comparative Example 1

[0241] This comparative example discloses a filamentous nickel-titanium alloy material, which is prepared by conventional DC magnetron sputtering TiN coating, and the specific steps include: substrate preparation, target material preparation, gas injection, target material heating, magnetic field application, film deposition and the like.

[0242] Comparative Example 2

[0243] This comparative example discloses a filamentous nickel-titanium alloy material, which uses PIII&D (plasma immersion ion implantation) technology to prepare a TiN coating, thereby obtaining a filamentous nickel-titanium alloy material. In which, the injected elements in the plasma are vertically injected into all surfaces in all directions under the action of a strong electric field force. The specific method includes:

[0244] The sample that has been polished to a certain surface roughness is placed on the sample stage of the vacuum chamber. After a certain vacuum degree is reached, nitrogen is introduced, and then the nitrogen is ionized into plasma through filament hot cathode discharge, so that the sample is completely immersed in the plasma of nitrogen element. At this time, a certain negative bias pulse voltage is applied to the sample. Under the action of the electric field between the sample and the vacuum chamber wall (the vacuum chamber wall is grounded as the positive pole), light-weight electrons quickly rush to the vacuum chamber wall, so that a nitrogen positive ion sheath is immediately formed around the sample. The nitrogen ions in the sheath are injected into the surface of the sample in all directions under the action of the strong electric field between the sample and the sheath.

[0245] Test example

[0246] This test example tests the performance of the filamentous nickel-titanium alloy material obtained in the embodiment and the comparative example, specifically including:

[0247] (1) The microstructure test (TiN layer cross-sectional morphology) of the filamentous nickel-titanium alloy materials in Comparative Example 1 and Example 1 was carried out, and the test results are as follows: Figure 2 and Figure 3 As shown. It can be seen that high-power pulsed magnetron sputtering (HiPIMS) discharge has the advantage of high ionization rate, making the coating have high density. In the process of preparing TiN coating, when using traditional DC magnetron sputtering, large-sized columnar crystals appear in the coating ( Figure 2 ), and in HiPIMS technology, the characteristics of high-concentration plasma make the bombardment of the coating surface more significant, and the ion mobility also increases accordingly. The bombardment of the growing TiN grains by high-energy ions and the high mobility increase the number of grain boundaries inside the coating and reduce the grain size, thus making the TiN coating present a typical nano-ultrafine crystal / amorphous structure ( Figure 3 ).

[0248] (2) The hardness of the wire-shaped nickel-titanium alloy materials in Comparative Example 1 and Example 1 was tested. The test results are as follows: Figure 4As shown. The TiN layer prepared by HiPIMS of the present invention (referred to as: HiPIMS-TiN coating) has a typical wear resistance advantage. According to the Hall-Petch effect, in crystalline materials, the grain size is negatively correlated with the hardness of the material. During the deposition process of the HiPIMS-TiN coating, the grain size is much smaller than the TiN coating obtained by conventional DC magnetron sputtering (referred to as: DC-TiN coating). The hardness and wear resistance of the coating of the present invention are greatly improved. The hardness of the HiPIMS-TiN coating is as high as about 31Gpa, while the hardness of the conventional DC-TiN is only about 26Gpa.

[0249] At the same time, due to the improvement of the hardness of the HiPIMS-TiN coating, its wear resistance is also greatly improved. In the friction and wear test, the wear rate of the conventional DC-TiN coating prepared in Example 1 is as high as 9.1×10 -6 mm 3 / Nm, while the wear rate of the HiPIMS-TiN coating prepared in Example 1 is only 3.1×10 -6 mm 3 / Nm. Therefore, the HiPIMS-TiN coating has a significant wear resistance advantage (the cross-sectional morphology of the TiN coating in Comparative Example 1 and Example 1 is shown in FIG. Figure 5-6 shown).

[0250] (3) Roughness test: The surface roughness of the conventional DC-TiN coating in Comparative Example 1 is 13±1.3 nm (e.g. Figure 7 , three-dimensional morphology of TiN coating under atomic force microscope), the surface roughness of HiPIMS-TiN coating in Example 1 is only 3±0.7nm (such as Figure 8 , three-dimensional morphology of TiN coating under atomic force microscope). It can be seen that under the same deposition power and atmosphere parameters, the HiPIMS technology used in the present invention can significantly reduce the roughness of the coating while improving the density and hardness of the coating.

[0251] It can be seen that, compared with Comparative Example 1, the pulsed magnetron sputtering of HiPIMS in the present invention uses a pulsed power supply with a rectangular wave voltage instead of a traditional DC power supply for magnetron sputtering deposition. The pulsed magnetron sputtering technology can effectively suppress the generation of arcs and eliminate the film defects caused thereby, and at the same time can increase the sputtering deposition rate, reduce the deposition temperature and other significant advantages.

[0252] (4) Bonding strength description: For the preparation of TiN coating of filamentary alloy material, compared with PIII&D technology (such as comparative example 2), there is a problem that the failure depth of the surface memory material is too high (the injection depth is about 60nm). The shallow injection technology used in the present invention has the high bonding strength advantage of PIII&D technology, while avoiding the problem of the failure depth of the surface memory material being too high. Specifically, Fig. 9 As shown in , in the early stage of the PIII&D technology, although the injection of N elements can reduce the surface Ni elements and improve the bonding strength, the penetration depth of N elements into the matrix material is too high, far greater than 0.5‰ (1-10nm) of the alloy wire radius. The shallow injection technology (HiPIMS) used in the embodiment of the present invention is to ionize Ti atoms and then drive Ti ions in the shallow layer (less than 10nm) of the substrate under a certain potential. Fig.10 ), and the injection depth can be controlled by adjusting the driving potential. This shallow injection layer becomes the film-base transition region, which can greatly improve the coating adhesion compared to direct deposition of TiN.

[0253] (5) Corrosion resistance test: Fig.11 As shown, the material prepared in Example 2 of the present invention has a nano-multilayer structure of TiN / Ti. The periodically added Ti sublayer cyclically interrupts the longitudinal growth of TiN grains, so that TiN is always in an amorphous / ultrafine grain state at the initial stage of nucleation ( Fig.10 ), and this ceramic / metal multilayer structure can greatly hinder the diffusion of corrosive media ( Fig.11 ), the coating has a significant corrosion resistance advantage.

[0254] (6) Internal stress test: The material coating prepared in Example 2 of the present invention has a multi-layer structure. While improving the corrosion resistance of the coating, the internal stress can be adjusted by adjusting the thickness of the Ti sublayer. Fig.12 The variation trend of the residual stress inside the ceramic (TiN) / metal multilayer coating with the change of the sub-layer modulation ratio is shown in the figure. It can be seen that when the modulation ratio between the sub-layers is kept within a certain range, the residual stress inside the coating (M3, M4) can be significantly reduced.

[0255] Fig.12 In the figure, (a) shows the diffraction peak position used for residual stress calculation, and (b) shows the residual compressive stress value of each coating. S1 is a pure ceramic coating (TiN layer), and M2~M5 represent the ratio (thickness ratio) of ceramic and metal sublayers in the ceramic (TiN) and metal (Ti) mixed multilayer coating.

[0256] If there is no special explanation, the actual meaning of "about" in the present invention is that the error is allowed within the range of ±2%, for example, about 100 is actually 100±2%×100. The "normal temperature" and "room temperature" in the present invention, if there is no special explanation, are about 20-30°C. The "between" in the present invention includes the number itself, for example, "between 2-3" includes the endpoint values ​​2 and 3.

[0257] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A nickel-titanium alloy material, characterized in that: The invention comprises a nickel-titanium alloy body and a coating containing TiN arranged on the surface of the body, wherein the coating is prepared by adopting a high-power pulsed magnetron sputtering technology.

2. The nickel-titanium alloy material according to claim 1, characterized in that: The nickel-titanium alloy body is a nickel-titanium alloy wire; Preferably, the diameter of the nickel-titanium alloy wire is 1 to 300 μm; and / or, the nickel-titanium alloy material further includes an element-injected transition layer, which is an element-injected transition layer formed in the nickel-titanium alloy body by the elements contained in the coating during high-power pulsed magnetron sputtering, and the element-injected transition layer is adjacent to the coating; Preferably, the thickness of the element injection transition layer is less than 30 nm; preferably, the thickness of the element injection transition layer is 0.01-30 nm.

3. The nickel-titanium alloy material according to claim 1, characterized in that: The thickness of the coating is 5 to 100 nm; and / or the hardness of the coating is above 28 GPa; and / or the wear rate of the coating is 6×10 -6 mm 3 / N·m or less; and / or, the surface roughness of the coating is 1.0 to 9.0 nm.

4. The nickel-titanium alloy material according to claim 1, characterized in that: The coating comprises a TiN layer; Preferably, the coating further comprises a Ti layer; Preferably, the Ti layer is located between the TiN layer and the nickel-titanium alloy body; Preferably, the coating comprises Ti layers and TiN layers which are alternately arranged in sequence; Preferably, the nickel-titanium alloy body is adjacent to the Ti layer.

5. A method for preparing a nickel-titanium alloy material, characterized in that: The method comprises the following steps: taking a nickel-titanium alloy body, and preparing a coating containing TiN on the surface of the nickel-titanium alloy body by using a high-power pulsed magnetron sputtering technology; Preferably, the nickel-titanium alloy body is a nickel-titanium alloy wire; Preferably, in the high-power pulsed magnetron sputtering technology, the discharge voltage to the target is 650 to 750 V; and / or, in the high-power pulsed magnetron sputtering technology, the bias voltage is -300 V to -800 V; and / or, in the high-power pulsed magnetron sputtering technology, the current is 60 to 120 A; Preferably, in the preparation method, the nickel-titanium alloy body is ion cleaned and then the coating is prepared by high-power pulsed magnetron sputtering technology.

6. Use of the nickel-titanium alloy material according to any one of claims 1 to 4 or the nickel-titanium alloy material prepared by the preparation method according to claim 5 in the preparation of implantable medical devices or medical implant materials.

7. A medical material, characterized in that: It includes the nickel-titanium alloy material according to any one of claims 1 to 4 or the nickel-titanium alloy material prepared by the preparation method according to claim 5.

8. A film coating device for a filamentous material, characterized in that: include: Rotation system: including an unwinding component for placing the wire-shaped material roll before coating and capable of unwinding the material roll, and a winding component for winding the wire-shaped material after coating; Cleaning system: including ion source excitation components; The coating system includes a coating area and a sputtering target arranged in the coating area; the coating method includes coating by adopting high-power pulsed magnetron sputtering technology; Preferably, the coating area includes a first coating chamber for preparing a Ti layer and a second coating chamber for preparing a TiN layer; Preferably, the first coating chambers are provided in plurality, and the second coating chambers are provided in plurality; Preferably, the first coating chamber and the second coating chamber are alternately arranged in the coating area; Preferably, the coating area includes a plurality of coating subareas, and a plurality of first coating cavities and second coating cavities are alternately arranged in the coating subareas.

9. A method for using the film coating device for filamentous materials according to claim 8, characterized in that: The steps include: Placing the filamentary material roll in an unwinding component of the rotating system, and moving the filamentary material obtained by unwinding the filamentary material roll into the cleaning system through the unwinding component; After the filamentary material is ion cleaned in the cleaning system, it is moved to the coating system for coating; Preferably, in the method of use, after the filamentary material is ion cleaned in the cleaning system, it is moved to the first coating chamber and the second coating chamber in sequence for coating, thereby forming a Ti layer and a TiN layer in sequence on the surface of the filamentary material.

10. A method for preparing a nickel-titanium alloy wire surface coating, characterized in that: include: Obtain target HiPIMS discharge parameter data and target coating deposition parameter data of nickel-titanium alloy wire; Based on the preset plasma diffusion transport model, the target HiPIMS discharge parameter data and the target coating deposition parameter data, the plasma distribution of the nickel-titanium alloy wire is predicted to obtain the sheath distribution characteristics and the plasma distribution characteristics; The nickel-titanium alloy wire is coated based on the sheath distribution characteristics and the plasma distribution characteristics to obtain a target coating.

Images