A plating process for forming a titanium coating on PEEK material

Abstract

This invention relates to a coating process for forming a titanium coating on PEEK material, comprising: S1, modifying the PEEK material by electron beam enhanced plasma cleaning, and bombarding the PEEK material surface with argon ions; S2, bombarding the PEEK material surface treated in S1 with metal ions, wherein charged metal ions generated by an ionization source are accelerated and bombarded on the PEEK material surface by a high negative bias voltage; S3, depositing a titanium coating on the PEEK material surface treated in S2, using titanium as the target material. This process can obtain a metal film layer with strong adhesion, dense coating, and biocompatibility on medical PEEK material. The deposited coating can maintain the low elastic modulus matching characteristics of the PEEK material surface and the porous structure of 3D printed PEEK. The deposition temperature is controlled below 100℃, which does not affect the mechanical properties of the material.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a coating process for forming a titanium coating on PEEK material. Background Technology

[0002] PEEK, or polyetheretherketone, is a bioinert material. Numerous studies and clinical applications have demonstrated that PEEK implantation in the human body has no adverse reactions. However, when implanted products require osseointegration, PEEK's chemical inertness and low surface energy slow down cell adhesion and protein absorption, which reduces osseointegration between the implant and tissue, resulting in a longer osseointegration time.

[0003] To address the aforementioned issues, 3D printing of PEEK material allows for pre-designed porous structures, which enhances PEEK's osseointegration capacity to some extent, but without altering the material's inherent bioinertness. Therefore, existing technologies improve the physicochemical properties of PEEK surfaces by depositing bioactive metals onto the surface to form a coating, thereby enhancing its osseointegration capacity.

[0004] For example, patent application CN113082291A discloses a modified polyaryletherketone (PAEK) compound and its preparation method and application. It uses thermal spraying to apply two layers of titanium coating, 130-200 μm thick, to the PEEK surface. This coating thickness affects the original surface roughness of PEEK, particularly the porous structure of 3D-printed PEEK and the surface elastic modulus of the material. Furthermore, thermal spraying cannot form a uniform coating on complex structures. Patent application CN115429940A discloses a method to enhance the stability of bioactive coatings. It directly forms microstructures composed of multiple microstructural units on PEEK through photolithography, micromilling, or laser processing to address the problems of insufficient mechanical stability, susceptibility to damage, short service life, and poor wear resistance of bioactive coatings in practical use environments. However, the method of forming microstructures is complex and cannot avoid the risk of coating detachment due to fretting wear. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of poor adhesion of coatings formed on PEEK materials. It provides a coating process for forming a titanium coating on PEEK materials. A bioactive metallic titanium coating with strong adhesion and uniform and dense coating is deposited on medical PEEK materials using PVD coating technology. This improves the bio-inert surface properties of PEEK and can completely preserve the elastic modulus of PEEK materials and the 3D printed porous structure. Moreover, the deposition temperature is below 100°C, which does not affect the original mechanical properties of the material, thereby enhancing the cell adhesion and bone integration ability after implantation.

[0006] The specific plan is as follows:

[0007] A coating process for forming a titanium coating on a PEEK material includes the following steps:

[0008] S1. The PEEK material is modified by electron beam enhanced plasma cleaning. Argon ions are used to bombard the surface of the PEEK material. The process control includes: vacuum degree of 1-5 Pa, cleaning time of 10-120 min, negative bias voltage of 50-300 V, arc current of 50-250 A, and anode current of 10-100 A. Under these conditions, a large number of argon ions are generated to bombard the surface of the PEEK material, which can enhance the bonding strength between the film layer subsequently formed on the surface and the material.

[0009] S2. The PEEK material surface treated in S1 is bombarded with metal ions. Charged metal ions generated by an ionization source are accelerated and bombarded on the PEEK material surface by a high negative bias voltage. The process control includes: vacuum degree of 0.1-1 Pa, bombardment time of 10-120 min, negative bias voltage of 200-1000 V, and ionization source current of 1-200 A. Under these conditions, a rough structure is generated on the PEEK surface, thereby further improving the adhesion, ensuring the stability of the film layer, and making it less prone to peeling off.

[0010] S3. Metal deposition is performed on the surface of the PEEK material treated in S2, using titanium as the target material, to deposit a titanium coating on the PEEK material.

[0011] Furthermore, the PEEK material has a porous structure, which can be a row of pores, a single pore, or an array of pores.

[0012] Preferably, the PEEK material is a porous fusion device formed by 3D printing.

[0013] Preferably, the thickness of the titanium coating is 1-1500 nm, more preferably 100-1000 nm, and even more preferably 200-800 nm;

[0014] Preferably, the adhesion of the titanium coating is 30-50 MPa, more preferably 35-45 MPa, and even more preferably 36-41 MPa.

[0015] Furthermore, in S1, argon ions are generated by an electron beam produced by arc discharge to bombard the surface of the PEEK material.

[0016] Furthermore, the arc discharge described in S1 adopts a cathode arc discharge method. During the cathode arc discharge process, a shield is used to prevent metal ions from depositing on the product surface, and an anode device is installed in the vacuum chamber. The presence of the shield blocks metal ions, while only electrons can pass through the gaps on both sides of the shield. After being accelerated by the electric field of the anode device, they bombard the argon gas to generate a large number of argon ions. Under the action of negative bias, the argon ions are accelerated to bombard the product surface, achieving a better surface treatment effect.

[0017] Furthermore, the cathode arc source mentioned in S1 can be a columnar arc source, a planar arc source, or a circular arc source, preferably a columnar arc source. When a columnar arc source is used, the target material utilization rate is high, and the plasma distribution is uniform, which can better perform electron bombardment, so that different positions on the material surface are treated to an equal degree, ensuring the stability and tight adhesion of the subsequent coating.

[0018] Furthermore, the anode device for arc discharge described in S1 is a copper electrode, which is connected to the positive terminal of the anode power supply;

[0019] Preferably, the copper electrode is a cylindrical copper electrode, installed in the middle of the vacuum chamber. This allows electrons generated by the cathode arc source to travel along the path of the rotating product before reaching the anode device, resulting in more thorough electron bombardment and a significant surface treatment effect.

[0020] Furthermore, the ionization source mentioned in S2 is one or more of cathode arc, magnetron sputtering, or laser discharge. The target material used for the ionization source is a titanium target, preferably magnetron sputtering. The power supply is one or more of DC, intermediate frequency, high frequency pulse power supply, radio frequency, or pulse, preferably a high frequency pulse power supply.

[0021] Furthermore, the process control in S3 includes: vacuum degree of 0.1-1 Pa, coating time of 10-120 min, negative bias voltage of 30-200 V, and target current of 1-100 A.

[0022] Furthermore, the metal deposition described in S3 involves depositing titanium onto the surface of the PEEK material to form a titanium coating through gradient negative bias and gradient target current, with a process gradient of 2-10 gradients. Gradient deposition can reduce film stress and improve film performance.

[0023] Preferably, the gradient negative bias voltage decreases from large to small; more preferably, the gradient negative bias voltage is 120-150V, 80-100V, or 40-50V.

[0024] Preferably, the gradient target current increases in a gradient from small to large; more preferably, the gradient target current is 6-8, 7-9, or 8-10A.

[0025] Preferably, the coating time increases with each gradient; more preferably, the coating time is 10-30, 15-45, or 20-60 min.

[0026] Furthermore, the purity of the target material is greater than 99.99 wt%, and argon gas is used to control the vacuum level in the coating process, with the argon gas purity greater than 99.99 wt%.

[0027] Beneficial effects:

[0028] In S1 of this invention, electron beam enhanced plasma bombardment generates a large number of argon ions through arc discharge, which bombard the surface of PEEK material, thereby increasing the surface energy of PEEK material and enhancing the bonding strength between the film layer and the material. The device is integrated into the coating equipment, is simple to operate, and is suitable for large-scale production.

[0029] Furthermore, the S2 metal ion bombardment of the present invention uses charged metal ions generated by the ionization source to bombard the PEEK material surface through high negative bias voltage, which causes the PEEK surface to produce a rough structure. At the same time, the accelerated ions can better fuse with the PEEK surface, further improving the stability of the film.

[0030] Furthermore, in S3 of this invention, metal deposition involves depositing metal particles onto the surface of a PEEK material using a gradient negative bias voltage and target current to form a metal film. This gradient deposition reduces the stress generated during the metal particle stacking process and increases the reliability of the film.

[0031] In summary, compared to thermal spraying, the thickness of the metal coating deposited by this invention can be controlled below 1000 nm, which better maintains the porous structure and the low elastic modulus matching characteristics of the PEEK material surface. The deposition temperature is controlled below 100℃, which does not affect the mechanical properties of the material. Attached Figure Description

[0032] To more clearly illustrate the technical solution of the present invention, the accompanying drawings will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0033] Figure 1 This is a photograph of the actual product provided in one embodiment 1 of the present invention.

[0034] Figure 2 SEM image of the titanium coating on the surface of the product in Example 1 of this invention.

[0035] Figure 3 SEM image of the porous fusion device in Embodiment 1 of this invention.

[0036] Figure 4 The coating adhesion test diagram in Example 1 of this invention. Detailed Implementation

[0037] Preferred embodiments of the present invention will now be described in more detail. While preferred embodiments of the present invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products. In the following embodiments, unless otherwise specified, "%" refers to weight percentage, and "parts" refers to parts by weight.

[0038] The testing standards used in this invention are as follows:

[0039] The coating thickness testing standard of this invention is as follows: the film thickness of the sample is tested in accordance with the scanning electron microscopy method for measuring the thickness of metallic coatings, as specified in GB / T 31563-2015.

[0040] The testing standard for the coating adhesion of this invention is as follows: the samples are tested in accordance with YY / T 0988.11 Surgical implant coatings Part 11: Tensile test method for calcium phosphate coatings and metal coatings.

[0041] Example 1

[0042] Arc target installation in coating machine Arc-shaped titanium target, magnetron target installation A cylindrical titanium target was used, and a high-frequency pulse power supply was employed for magnetron sputtering. The cleaned and dried PEEK porous fusion vessel and tensile sample were placed in a vacuum coating machine with an initial temperature of 31℃. Coating began when the vacuum level reached 0.003 Pa. The S1 electron beam enhanced plasma bombardment process involved a vacuum level of 2 Pa, a cleaning time of 15 min, a negative bias of 150 V, an arc current of 60 A, and an anode current of 15 A. The S2 metal ion bombardment process involved a vacuum level of 0.1 Pa, a bombardment time of 30 min, a negative bias of 500 V, and a magnetron sputtering current of 1.5 A. The S3 metal deposition process involved a vacuum level of 0.5 Pa, negative bias gradients of 120, 80, and 40 V, magnetron sputtering current gradients of 7, 7.5, and 8 A, and time gradients of 10, 15, and 20 min. The coating was completed at 75℃. Specific process parameters are shown in Table 1.

[0043] Tests showed that the film thickness was approximately 350 nm and the coating adhesion was 41 MPa.

[0044] Figure 1 This is a picture of the actual product after the coating is completed. As you can see, the surface of the porous fusion device has dense pores. After the coating, the pore structure is still uniform, just like the sample without coating. Figure 2 This is an SEM image of the titanium coating surface, magnified 3000 times. As you can see, the titanium coating is very dense. Figure 3 This is a SEM image of the porous fusion device near the holes, showing that the 3D printed holes are also covered with a titanium coating. Figure 4 It is a sample that failed under tensile stress, with a tensile strength greater than 30 MPa.

[0045] Table 1 Process parameters of Example 1

[0046]

[0047]

[0048] Example 2

[0049] Arc target installation in coating machine Arc-shaped titanium target, magnetron target installation A cylindrical titanium target was used, and a high-frequency pulsed power supply was employed for magnetron sputtering. The cleaned and dried 3D-printed PEEK porous fusion vessel and tensile sample were placed in a vacuum coating machine with an initial temperature of 27℃. Coating began when the vacuum level reached 0.003 Pa. The S1 electron beam enhanced plasma bombardment process used a vacuum level of 1.8 Pa, a cleaning time of 15 min, a negative bias of 100 V, an arc current of 70 A, and an anode current of 20 A. The S2 metal ion bombardment process used a vacuum level of 0.1 Pa, a bombardment time of 30 min, a negative bias of 700 V, a magnetron sputtering current of 1.8 A, and a high-frequency pulsed power supply. The S3 metal deposition process used a vacuum level of 0.5 Pa, with negative bias gradients of 120, 90, and 60 V, magnetron sputtering current gradients of 7, 7.5, and 8 A, and time gradients of 20, 30, and 40 min. The final coating temperature was 84℃. Specific process parameters are shown in Table 2.

[0050] Tests showed that the film thickness was approximately 690 nm and the coating tensile strength was 38 MPa.

[0051] Table 2 Process parameters of Example 2

[0052]

[0053] Example 3

[0054] Arc target installation in coating machine Arc-shaped titanium target, magnetron target installation A cylindrical titanium target was used, and a high-frequency pulse power supply was employed for magnetron sputtering. The cleaned and dried PEEK fusion vessel and tensile sample were placed in a vacuum coating machine, and coating began when the vacuum level reached 0.003 Pa. The S1 electron beam enhanced plasma bombardment process had a vacuum level of 1.8 Pa, a cleaning time of 15 min, a negative bias of 100 V, an arc current of 70 A, and an anode current of 20 A. The S2 metal ion bombardment process had a vacuum level of 0.1 Pa, a bombardment time of 30 min, a negative bias of 700 V, a magnetron sputtering current of 1.8 A, and employed a high-frequency pulse power supply. The S3 metal deposition process had a vacuum level of 0.5 Pa, negative bias gradients of 120, 90, and 60 V, magnetron sputtering current gradients of 7, 7.5, and 8 A, and time gradients of 10, 15, and 20 min. The coating completion temperature was 88℃. Specific process parameters are shown in Table 3.

[0055] Tests showed that the film thickness was approximately 1020 nm and the coating tensile strength was greater than 36 MPa.

[0056] Table 3 Process parameters of Example 3

[0057]

[0058] Comparative Example 1

[0059] Referring to Example 3, the arc target installation in the coating machine Arc-shaped titanium target, magnetron target installation A cylindrical titanium target was used, and a high-frequency pulse power supply was employed for magnetron control. The cleaned and dried PEEK fusion vessel and tensile specimen were placed in a vacuum coating machine, and coating began when the vacuum level reached 0.003 Pa.

[0060] This comparative example uses a conventional ion source cleaning method, employing glow discharge cleaning under the conditions of step DZS1 (DZS1 conditions are shown in Table 4, representing a high-bias glow discharge cleaning process used in conventional processes). The high-bias glow discharge cleaning process is controlled under the following conditions: vacuum 1.8 Pa, cleaning time 15 min, negative bias 1000 V. For step S2, metal ion bombardment, the vacuum is 0.1 Pa, bombardment time 30 min, negative bias 700 V, magnetron sputtering current 1.8 A, and a high-frequency pulse power supply is used. For step S3, metal deposition, the vacuum is 0.5 Pa, negative bias gradients are 120, 90, and 60 V, magnetron sputtering current gradients are 7, 7.5, and 8 A, and time gradients are 10, 15, and 20 min. The final deposition temperature is 81℃. Specific process parameters are shown in Table 4.

[0061] Tests showed that the film thickness was approximately 1020 nm and the coating tensile strength was approximately 17 MPa.

[0062] Table 4 Process parameters of Comparative Example 1

[0063]

[0064]

[0065] Comparative Example 2

[0066] This comparative example is based on Example 3, except that step S2 is omitted, and deposition proceeds directly after S1. The coating completion temperature is 80°C. Specific process parameters are shown in Table 5.

[0067] Tests showed that the film thickness was approximately 960 nm and the coating tensile strength was 14 MPa.

[0068] Table 5 Process parameters of Comparative Example 2

[0069]

[0070] Comparative Example 3

[0071] This comparative example is based on Example 3, except that step S3 uses conventional metal deposition. The coating completion temperature is 103°C. Specific process parameters are shown in Table 6.

[0072] Tests showed that the film thickness was approximately 1120 nm and the coating tensile strength was 24 MPa.

[0073] Table 6 Process parameters of Comparative Example 3

[0074]

[0075] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0076] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0077] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A coating process for forming a titanium coating on a PEEK material, characterized in that: Includes the following steps: S1. The PEEK material is modified by electron beam enhanced plasma cleaning. Argon ions are generated by the electron beam generated by arc discharge to bombard the surface of the PEEK material. The arc discharge adopts the cathode arc discharge method. During the cathode arc source discharge process, a shield is used to prevent metal ions from depositing on the product surface, and an anode device is installed in the vacuum chamber. Process control includes: vacuum degree 1-5Pa, cleaning time 10-120min, negative bias voltage 50-300V, arc current 50-250A, anode current 10-100A; S2. The PEEK material surface treated in S1 is bombarded with metal ions. Charged metal ions generated by the ionization source are accelerated and bombarded on the PEEK material surface by a high negative bias voltage. The process control includes: vacuum degree of 0.1-1 Pa, bombardment time of 10-120 min, negative bias voltage of 200-1000 V, and ionization source current of 1-200 A. S3. Metal deposition is performed on the surface of the PEEK material treated in S2. The metal deposition uses a gradient negative bias voltage and a gradient target current to deposit titanium onto the surface of the PEEK material to form a titanium coating. The gradient negative bias voltage decreases from large to small, the gradient target current increases from small to large, and the deposition time increases for each gradient. Titanium is used as the target material to deposit a titanium coating on the PEEK material.

2. The coating process for forming a titanium coating on PEEK material according to claim 1, characterized in that: The PEEK material has a porous structure.

3. The coating process for forming a titanium coating on PEEK material according to claim 2, characterized in that: The PEEK material is a porous fusion device formed by 3D printing.

4. The coating process for forming a titanium coating on PEEK material according to claim 2, characterized in that: The thickness of the titanium coating is 1-1500 nm.

5. The coating process for forming a titanium coating on a PEEK material according to claim 4, characterized in that: The thickness of the titanium coating is 100-1000 nm.

6. The coating process for forming a titanium coating on a PEEK material according to claim 5, characterized in that: The thickness of the titanium coating is 200-800 nm.

7. The coating process for forming a titanium coating on a PEEK material according to claim 2, characterized in that: The adhesion of the titanium coating is 30-50 MPa.

8. The coating process for forming a titanium coating on a PEEK material according to claim 7, characterized in that: The adhesion of the titanium coating is 35-45 MPa.

9. The coating process for forming a titanium coating on a PEEK material according to claim 8, characterized in that: The adhesion of the titanium coating is 36-41 MPa.

10. The coating process for forming a titanium coating on a PEEK material according to claim 1, characterized in that: The cathode arc source mentioned in S1 is a cylindrical arc source, a planar arc source, or a circular arc source.

11. The coating process for forming a titanium coating on a PEEK material according to claim 1, characterized in that: The anode device for arc discharge described in S1 is a copper electrode, which is connected to the positive terminal of the anode power supply.

12. The coating process for forming a titanium coating on a PEEK material according to claim 11, characterized in that: The copper electrode is a cylindrical copper electrode, installed in the middle of the vacuum chamber.

13. The coating process for forming a titanium coating on a PEEK material according to any one of claims 1-12, characterized in that: The ionization source described in S2 is one or more of cathode arc, magnetron sputtering, and laser discharge, and the power supply is one or more of DC, high-frequency pulse power supply, and radio frequency.

14. The coating process for forming a titanium coating on a PEEK material according to any one of claims 1-12, characterized in that: The process control in S3 includes: vacuum degree of 0.1-1Pa, coating time of 10-120min, negative bias voltage of 30-200V, and target current of 1-100A.

15. The coating process for forming a titanium coating on a PEEK material according to claim 14, characterized in that: The metal deposition described in S3 has a process gradient of 2-10 gradients.

16. The coating process for forming a titanium coating on a PEEK material according to claim 15, characterized in that: The gradient negative bias voltage is 120-150V, 80-100V, and 40-50V; the gradient target current is 6-8A, 7-9A, and 8-10A; and the coating time is 10-30min, 15-45min, and 20-60min.

17. The coating process for forming a titanium coating on a PEEK material according to any one of claims 1-12, characterized in that: The purity of the target material is greater than 99.99 wt.%, and argon gas with a purity greater than 99.99 wt.% is used to control the vacuum level in the coating process.

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