1. A method for plating DLC film on metal surface is characterized by comprising the following steps:

s1, preprocessing the base material;

s2, plating a DLC film on the surface of the base material by adopting a microwave plasma chemical vapor deposition method.

2. The method according to claim 1, wherein in step S1, the base material is a metal material.

3. The method according to claim 2, wherein the metallic material is selected from medical stainless steel, cobalt and its alloys, titanium and its alloys, nickel and its alloys, or magnesium and its alloys.

4. The method of claim 1, wherein the pre-treatment comprises a polishing treatment and an ultrasonic cleaning step.

5. The method according to claim 1, wherein the step S2, the process parameters for plating DLC like thin film on the surface of the substrate material include: at a temperature of 500-1000 ℃ and containing CH₄And H₂The gas of (1) has an introduction flow rate of 200 to 400sccm, a gas injection time of 5 to 180 minutes, and a DLC film deposition time of 5 to 180 minutes.

6. The method of claim 5, wherein CH₄And H₂The injection proportion of (A) is 5-30: 185 to 390.

7. The method according to claim 5, wherein the gas injection time is preferably 5 to 120 minutes.

8. The method as claimed in claim 5, wherein the deposition time of the DLC film is preferably 30 to 60 minutes.

9. A metal surface-plated DLC film produced by the method according to any one of claims 1 to 8.

10. Use of the DLC film according to claim 9 for the preparation of medical implant materials or medical devices.

Background

The metallic orthopedic implant material has been widely applied to the repair, substitution and regeneration of human hard tissues such as artificial joints, artificial bones, dental implants and the like clinically due to good mechanical properties, corrosion resistance and excellent biocompatibility.

The good osseous bonding of the metal material implanted into the body and the bone tissue of the body at the interface is a prerequisite for ensuring the stable transmission of mechanical load, and therefore is also a necessary condition for ensuring that the implant can stably function in the human body for a long time. Although most metal implant materials have good biocompatibility, the metal implant materials lack osteoconductivity and osteoinduction capability due to the fact that the metal implant materials are biologically inert in vivo, cannot rapidly and effectively form firm osseous bonding with bone tissues in a human body, and meanwhile, when the metal surface is in contact with the human body for a long time (or temporarily), biological reaction problems such as toxicity, sensitization, inflammation, carcinogenesis, thrombus and the like occur in the environment of the human body. The biological performance of the metal implant material is mainly determined by the physical and chemical properties of the surface of the metal implant material, and the biological performance of the metal implant material can be improved on the premise that the advantages of the material are not influenced by the surface modification.

The medical stainless steel containing the DLC film has better osteogenesis promoting ability than untreated medical stainless steel. Due to the uneven surface coating of the sample, the corrosion rate of stainless steel is accelerated in the soaking process, local corrosion occurs in only 7 days, and pitting corrosion is serious.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides a method for plating a DLC film on a metal surface, which can uniformly cover the metal surface and improve the corrosion resistance of the metal surface.

The invention also provides the DLC film plated on the metal surface prepared by the method.

The invention also provides an application of the DLC film.

According to a first aspect of the present invention, there is provided a method for plating a DLC film on a metal surface, the method comprising the steps of:

s1, preprocessing the base material;

s2, plating a diamond-like carbon (DLC) film on the surface of the base material by adopting a microwave plasma chemical vapor deposition Method (MPCVD).

In some embodiments of the present invention, in step S1, the base material is a metal material.

In some embodiments of the invention, the metallic material is selected from medical stainless steel, cobalt and alloys thereof, titanium and alloys thereof, nickel and alloys thereof, magnesium and alloys thereof.

In some preferred embodiments of the present invention, the metal material is medical stainless steel.

In some embodiments of the present invention, the pretreatment in step S1 includes a polishing treatment and an ultrasonic cleaning step.

In some embodiments of the present invention, the pretreatment step S1 includes polishing the base material with sandpaper and ultrasonic cleaning with ethanol solution as a cleaning agent.

In some embodiments of the invention, the coated abrasive is one or more of 400#, 800#, and 1600 #.

In some embodiments of the present invention, the ethanol is 50 to 95% by volume.

In some embodiments of the present invention, in step S2, the process parameters for plating the diamond-like carbon film (DLC film) on the surface of the substrate material include: at a temperature of 500-1000 ℃ and containing CH₄And H₂The gas (2) has an introduction flow rate of 200 to 400sccm (Standard Cubic center per Minute), a gas injection time of 5 to 180 minutes, and a DLC film deposition time of 5 to 180 minutes.

In some embodiments of the invention, the CH is₄And H₂The injection ratio of (A) is 5-30: 185-390.

In some preferred embodiments of the present invention, the above CH₄And H₂The injection ratio of (3) is 5: 195.

In some embodiments of the present invention, the gas injection time is preferably 5 to 120 minutes.

In some preferred embodiments of the present invention, the gas injection time is 60 minutes.

In some preferred embodiments of the present invention, the deposition time of the DLC film is preferably 30 to 60 minutes.

The metal surface-plated DLC film produced by the above method according to the second aspect of the present invention.

The application of the DLC film plated on the metal surface provided by the third aspect of the invention is the application in the preparation of medical implant materials or medical instruments.

The method for plating the DLC film on the metal surface and the application thereof according to the embodiment of the invention have at least the following beneficial effects: the scheme of the invention adopts an MPCVD system, takes a metal material as a substrate, H₂And CH₄For the experimental precursor, a DLC film was deposited on the metal surface. In the deposition process, the DLC film with good comprehensive performance is prepared by adjusting the process parameters including gas flow ratio, deposition temperature, deposition time and the like, so that the DLC film can be uniformly covered on the surface of the metal material. The metal with the DLC film plated on the surface prepared by the scheme of the invention has low cost and simple preparation process, has wide application prospect in the fields of orthopedic implant materials, functional materials, bioactive materials and the like, and is suitable for batch and industrial production.

Drawings

The invention is further described with reference to the following figures and examples, in which:

FIG. 1 is a graph showing the results of an analysis experiment of the surface morphology of a medical stainless steel coated with a DLC film at different temperatures according to a test example of the present invention;

FIG. 2 is an SEM scanning electron micrograph of a medical stainless steel sample #1-1 coated with a DLC film according to a test example of the present invention;

FIG. 3 is an SEM scanning electron micrograph of a medical stainless steel sample #1-2 coated with a DLC film according to a test example of the present invention;

FIG. 4 is an SEM scanning electron micrograph of a medical stainless steel sample #1-3 coated with a DLC film according to a test example of the present invention;

FIG. 5 is an SEM scanning electron micrograph of a medical stainless steel sample #1-4 coated with a DLC film according to a test example of the present invention;

FIG. 6 is a graph showing the results of an analysis experiment of the surface morphology of a medical stainless steel coated with a DLC film according to different gas flow ratios in the test examples of the present invention;

FIG. 7 is an SEM morphology feature drawing of medical stainless steel sample #2-1 with a DLC film coated on the surface magnified 30000 times in the test example of the present invention;

FIG. 8 is an SEM morphology feature plot of medical stainless steel sample #2-2 with a surface coated with a DLC film magnified 30000 times in a test example of the present invention;

FIG. 9 is an SEM morphology feature plot of medical stainless steel sample #2-3 with a surface covered with DLC film magnified 30000 times in the test example of the present invention;

FIG. 10 is a graph showing the results of an analysis experiment of the surface morphology of medical stainless steel coated with DLC film according to the present invention, which was prepared at different deposition times in the test examples;

FIG. 11 is a microscopic morphology view of a medical stainless steel sample #3-1 coated with a DLC film in a test example of the present invention after SEM magnification of 10000 times;

FIG. 12 is a microscopic morphology view of a medical stainless steel sample #3-2 coated with a DLC film in a test example of the present invention after SEM magnification of 10000 times;

FIG. 13 is a microscopic morphology view of a medical stainless steel sample #3-3 coated with a DLC film in a test example of the present invention after SEM magnification of 10000 times;

FIG. 14 is a microscopic morphology view of a sample #3-4 of medical stainless steel coated with DLC film in a test example of the present invention after SEM magnification of 10000 times;

FIG. 15 is a microscopic morphology view of a sample #3-5 of medical stainless steel coated with DLC film in the test example of the present invention after SEM magnification of 10000 times;

FIG. 16 is a microscopic morphology view of a sample #3-6 of medical stainless steel coated with DLC film in the testing example of the present invention after SEM magnification of 10000 times;

FIG. 17 is a Raman spectrum and a Gaussian fit graph of a 316L stainless steel surface deposited film in a test example of the present invention;

FIG. 18 is a surface topography of samples soaked in Hank's solution in the test examples of the present invention, wherein #3-5 is the medical stainless steel coated with DLC film prepared in example 1 and #3-7 is the blank sample without treatment.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.

Example 1

The embodiment prepares the medical stainless steel with the DLC film coated on the surface, and the specific process comprises the following steps:

(1) pretreatment: a medical 316L stainless steel sample with the length, width and height of 20mm multiplied by 2mm is sequentially polished by sand paper of No. 400, No. 800 and No. 1600 to process the surface of the sample, and then the sample is cleaned for 30 minutes in an ultrasonic cleaning machine by using ethanol solution as a cleaning agent.

(2) And (6) vacuumizing. Taking out the sample, drying, putting the sample into a vacuum preparation chamber, starting the device, and vacuumizing the vacuum chamber through an air exhaust system.

(3) And (5) cleaning. Introduction of H₂The gas flow is adjusted to 200sccm, the gas pressure is 10torr, the gas is stopped to be introduced after the preset gas flow is reached, then the vacuumizing is carried out, and the steps are repeated for 3 times, so that impurities and dirt on the surface of the material disappear, and the reaction cavity is kept in a clean state.

(4) And (4) starting. Introduction of H₂Gradually increasing the gas flow and the reaction gas pressure to enable the reflection power value to be less than 300w after the microwave power supply is started, and finishing the glow starting; otherwise, the microwave power supply is turned off, the pressure intensity and the gas flow of the reaction gas are changed again, and then the microwave power supply is turned on.

(5) The power of the apparatus was adjusted to 3000w at a pressure of 110tor to increase the substrate temperature to 900 ℃.

(6) And (6) coating. Introduction of CH₄Adjusting H₂Flow rate of gas, make CH₄And H₂And (5) when the gas flow ratio reaches 10:190, coating for 60 min.

(7) And (5) cooling. Stopping introducing CH when the deposition time is reached₄Introduction of only H₂And gradually reducing the power and the air pressure until the temperature of the substrate is slowly reduced to the room temperature.

(8) And (5) stopping the machine. Stopping the introduction of H₂The microwave power supply is turned off, vacuum breaking is performed, and then the sample preparation chamber is opened to take out the sample.

Test example

1. Effect of deposition temperature on the preparation of DLC films

In order to study the influence of temperature on the morphological structure characteristics of the DLC film, a single-factor experiment was performed, which was the same as in example 1 except that CH was used₄And H₂The gas flow ratio is 5:195, the deposition time is 15min, the temperatures are respectively 600 ℃, 700 ℃, 800 ℃, 900 ℃ and 1000 ℃, the experimental scheme is shown in Table 1, 316L stainless steel samples #1- #1-5 with the surface covered with the DLC film are obtained, the direct view of the samples is shown in figure 1, and the SEM appearance of the surfaces of the samples #1- #1-4 amplified by 10000 times is shown in figure 2-5.

TABLE 1 preparation of DLC films at different temperatures

TABLE 2 characteristics of films deposited at different temperatures

The experimental results are shown in table 2 and fig. 1-2, wherein fig. 1 is a visual representation of the appearance of 316L stainless steel deposited with DLC film at different temperatures, and table 2 is a characteristic of the deposited film at different temperatures, and it can be seen from the graph that the surface of sample #1-1 is black, the film layer is not uniform, loose and easy to fall off; the #1-2 sample has a black surface, and a film layer is not uniform, loose and easy to fall off; the surface of the sample #1-3 is brown, the film layer is uniform, and the sample is not easy to fall off; samples #1-4 were light gray with a non-uniform but dense film layer; the film layer of sample #1-5 exhibited local melting of the substrate, and thus it was found that the deposition effect of the DLC film prepared at 900 ℃ was the best. Sample #1-5 was not topographically analyzed by SEM scanning electron microscopy because it melted due to excessive local temperature.

FIGS. 2 to 5 are SEM images of DLC films prepared at different temperatures, and it can be seen from the SEM images that FIG. 2 is the SEM image of sample #1-1, the appearance of DLC film is in the shape of uniformly scattered cauliflower, and most of the deposits are graphite phases with loose and porous structure; FIG. 3 is an SEM image of sample #1-2, in which the deposit tends to aggregate with each other, and the particles of the deposit formed are enlarged, but the structure is still loose; FIG. 4 is an SEM scanning electron micrograph of sample #1-3, which shows that the loose and porous characteristics of the deposit of #1-3 are significantly improved compared with those of #1-2, but the surface of the deposit is rough and nano-scale spherical particles exist; FIG. 5 is SEM scanning electron micrographs of samples #1-4, showing that the phenomenon of loose and porous deposits disappears, spherical particles decrease, and most of the deposits are diamond phases with smooth surfaces and dense structures. The comparison shows that when the temperature is lower, the deposit gas phase reaction tends to generate a graphite phase; at higher temperatures, diamond phases tend to form. Therefore, by observing the change of the shape structure of the DLC film on the surface of 316L stainless steel at different temperatures, the film structure gradually becomes compact and smooth from loose and porous along with the increase of the temperature, the graphite phase structure of the film tends to be transformed to the diamond phase, the bonding force between the DLC film and the stainless steel matrix is enhanced, and therefore the deposition temperature of the DLC film is 900 ℃.

In the experimental process, the medical stainless steel sample with the DLC film coated on the surface prepared in the embodiment is measured by a high-temperature infrared thermometer, and the fact that the surface temperature of the sample is greatly different can be found. Sample #1-1 after one hour of deposition, the temperature was measured at the center of the sample surface at 600 ℃, with the center expanding outward, the temperature gradually increasing, and the edge angle reaching 680 ℃. The vibration of free electrons is mainly used for playing a leading role in the thermal conductivity of the stainless steel, the vibration amplitude of the free electrons is gradually increased along with the increase of the temperature, the resistance of the electrons to conduct motion along the crystal is increased, meanwhile, the crystal lattice of the stainless steel is linearly expanded when the stainless steel is heated, the stainless steel is slightly deformed, and generally the edge of the stainless steel is warped, so that the contact area of a base body and a cooling system of a base of a deposition system is changed, the heat dissipation capacity of the base body is inconsistent, and the conditions of low surface temperature, low intermediate temperature and high edge temperature of the stainless steel are caused, namely obvious temperature nonuniformity. It is inferred that one of the factors for the occurrence of significant unevenness in the film deposited on the surface of the sample is caused by unevenness in the surface temperature distribution of the sample during the preparation.

2. Influence of reaction gas flow ratio on morphological characteristics of DLC film on surface of 316L stainless steel

To study the influence of the reaction gas flow ratio on the morphology of DLC films, the experimental method was the same as in example 1, except that the deposition time was 10min, and only CH was changed₄And H₂Samples #2-1 to #2-3 of 316L stainless steel coated with a DLC film on the surface were prepared according to the gas flow ratio. The experimental protocol is shown in table 3, and the optical profile of the deposited films at different gas flow ratios is shown in table 4 and fig. 6-9.

TABLE 3 preparation of DLC films at different gas flows

TABLE 4 characteristics of deposited films at different gas flow ratios

The experimental results are shown in table 4 and fig. 6 to 9, where fig. 6 is a visual representation of the appearance of 316L stainless steel deposited with DLC films at different gas flow ratios, table 4 is a characteristic of the deposited films at different gas flow ratios, and as can be seen from the graphs,the surface of the sample No. 2-1 is silver gray, and the film layer is uniform and compact; the surface of the sample No. 2-2 is light gray, and the film layer is uniform and compact; 2-3 brown, even and loose film; thus, it is known that₄And H₂The deposition effect of the DLC film prepared when the gas flow ratio is 10:190 is the best.

FIGS. 7 to 9 are SEM scanning electron micrographs of DLC films at different gas flow ratios, wherein FIG. 7 is a 30000 times magnified SEM topographic map of sample #2-1, FIG. 8 is a 30000 times magnified SEM topographic map of sample #2-2, and FIG. 9 is a 30000 times magnified SEM topographic map of sample # 2-3. As can be seen from the figure, as the flow ratio of the reaction gas is gradually increased, namely CH₄The concentration is gradually increased, large particles formed by the aggregation of the sediments on the surface of the 316L stainless steel matrix appear as small particles with nanometer sizes, the appearance of the film gradually becomes rough from smooth, and the film tends to be changed into a loose porous structure. As the concentration of the carbon source increases, the reaction between the active groups is more favorable for the formation of a graphite phase, resulting in a phase change of the thin film tissue toward a loosely dispersed graphite phase, so it is known that CH₄And H₂The deposition effect of the DLC film prepared when the gas flow ratio is 10:190 is the best.

3. Influence of deposition time on morphological characteristics of DLC film on surface of 316L stainless steel

In order to study the influence rule of different deposition times on the appearance characteristics of the DLC film, the experimental method is the same as that in example 1, except that the deposition times are 5, 10, 20, 30, 60 and 120min in sequence, and 316L stainless steel samples #3-1 to #3-6 with the DLC film covered on the surface are respectively obtained. The samples prepared in example 1 were #3-5, the experimental protocol is shown in Table 5, and the optical topography of the deposited films at different gas flow ratios is shown in Table 6 and FIGS. 10-16.

TABLE 5 preparation of DLC films at different deposition times

TABLE 6 characteristics of films deposited at different deposition times

The experimental results are shown in table 6 and fig. 10-16, fig. 10 is a visual representation of the appearance of 316L stainless steel deposited with DLC film at different times, table 6 is the characteristic of the deposited film at different times, and it can be seen from the graph that the sample #3-1 has gray black surface and dense but non-uniform film layer; the surface of sample #3-2 is light gray, and the film layer is dense but not uniform; the surface of the sample #3-3 is dark gray, and the film layer is compact but uneven; the surface of the sample #3-4 is gray, and the film layer is compact but uneven; the sample No. 3-5 has silvery white surface and uniform and compact film layer; the sample #3-6 had a dark yellow surface and a dense but non-uniform film layer, and thus it was found that the deposition effect of the DLC film prepared with a deposition time of 60min was the best.

Fig. 11 to 16 are SEM scanning electron micrographs of DLC films prepared at different times, where fig. 11 is a microscopic topography of sample #3-1 after SEM magnification of 10000 times, fig. 12 is a microscopic topography of sample #3-2 after SEM magnification of 10000 times, fig. 13 is a microscopic topography of sample #3-3 after SEM magnification of 10000 times, fig. 14 is a microscopic topography of sample #3-4 after SEM magnification of 10000 times, fig. 15 is a microscopic topography of sample #3-3 after SEM magnification of 10000 times, and fig. 16 is a microscopic topography of sample #3-3 after SEM magnification of 10000 times. As can be seen from the figure, in the initial growth stage of the film, as the deposition time increases, island-shaped sediment particles are mutually swallowed and gradually grow larger; when the deposition time is increased to 30min, mutual contact occurs between grain boundaries; when the deposition time reaches 60min, the mutual swallowing process among the deposits is basically completed, and a continuous DLC film structure is formed; then, the deposition time is continuously increased, obvious grain boundary appears, and recrystallization phenomenon occurs at the same time, so that new fine grains are generated.

4. Structural analysis of DLC film on stainless steel surface

In order to determine whether the deposited film was a DLC film, sample #3-1 having a short deposition time was selected for Raman spectroscopy.

The results of the experiment are shown in fig. 17 and table 7. FIG. 17 is a Raman spectrum of a 316L stainless steel surface deposited film and a Gaussian fit thereofThe curve, Table 7, is a Gaussian fit of the data, and it can be seen that the Raman spectrum is from 1349cm^-1Nearby one acromion and 1568cm^-1A broad peak is formed nearby, which accords with the Raman spectrum characteristic of the DLC film, so that the prepared film is the DLC film. As can be seen from the table, the relative intensity ratio I of the D peak to the G peak_D/I_GThe value is relatively high at 3.13, which indicates sp for the film at this process parameter³The hybridization is very high, and the content of diamond phase is relatively high.

TABLE 7 Gaussian fitting data for sample #3-1

5. Bone growth promoting ability test

A medical stainless steel sample (#3-5 sample) with a DLC film coated on the surface and the best bonding force between the film layer and the substrate and a sample without surface modification treatment (blank group #3-7 sample) are selected, and the generation conditions of Ca-P based precipitates on the surface of the sample after the samples in the two groups are soaked in Hank's solution containing Ca and P for 1, 3 and 7 days are compared. The simulated body fluid adopted in the experiment is Hank's solution, and the main preparation method comprises the steps of mixing 8g of NaCl, 0.40g of KCl and CaCl₂ 0.14g、NaHCO₃0.35g、C₆H₁₂O₆1.00g、MgCl₂·6H₂0 0.10g、MgSO₄·7H₂O 0.06g、KH₂PO₄ 0.06g、NaHPO₄·12H₂0.06g of O was dissolved in 1L of deionized water.

The results of the topography experiment of the surfaces of the two groups of samples, which are magnified 500 times by a metallographic microscope at different times, are shown in fig. 18, and it can be seen that the surface change degree of the blank sample is still very small and the generation amount of white precipitates is very small after the blank sample is soaked for 7 days by comparing the 2 groups of samples. In contrast, the medical stainless steel sample prepared in example 1, which had a DLC film coated on the surface, was immersed for one day, and the formation of dispersed white cloudy particles was observed on the surface of the sample, and the cloudy particles gradually increased with the lapse of the immersion time. When the soaking was prolonged to 7 days, it was clearly observed that the white precipitates were continuously enriched to form flaky Ca-P based sedimentary materials. The results show that the stainless steel having a DLC film on the surface promotes the deposition of Ca-P based precipitates, compared to stainless steel which has not been surface-treated, i.e., the DLC film-containing medical stainless steel has a better bone-promoting ability.

In the test example of the scheme of the invention, a Verios G4 UC type scanning electron microscope produced by Thermo Fisher scientific company is adopted to detect the medical stainless steel sample with the DLC film coated on the surface. The principle is to analyze the surface topography of a sample by using secondary electron signals generated by electron beam bombardment on the surface of the sample. The highest acceleration voltage of the device is 30KV, the electron beam resolution can observe the sample morphology of 0.6nm under the voltage of 30KV, and a corresponding energy spectrometer is provided for qualitatively analyzing the element types and the distribution conditions of the samples so as to realize the homotopic analysis of the sample morphology characteristics and the component composition.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. Furthermore, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.