A super-thick diamond-like carbon film prepared by a double-pulse technique and a preparation method thereof

Abstract

The application discloses a super-thick diamond-like carbon film prepared by a double-pulse technology, and the method comprises the following steps: forming an amorphous carbon film by treating with a pulse magnetic field and a pulse electric field during carbon atom deposition on a sample surface. The amorphous carbon film prepared by the method can keep high hardness, reduce internal stress, and prevent the film layer from falling off at a large thickness.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of thin film preparation, and particularly relates to a super-thick diamond-like carbon film prepared by using a double-pulse technology and a preparation method thereof. BACKGROUND

[0002] Amorphous carbon (a-C) film is a kind of amorphous carbon film containing diamond structure (sp 3 bond, face-centered cubic structure) and graphite structure (sp 2 bond, hexagonal sheet structure), and has significant performance such as high hardness, adjustable resistivity, good optical performance, excellent biocompatibility, good wear resistance and corrosion resistance, chemical inertness, etc., and has great application prospects in the industries of machinery, petroleum, natural gas, biomedicine, optical devices, electronics, etc.

[0003] As a kind of carbon-based functional thin film material with the most engineering application prospects at present, a-C film has attracted the attention of countries and enterprises all over the world. The main methods for preparing a-C film include physical vapor deposition (PVD) and chemical vapor deposition (CVD). The CVD technology includes planar hollow cathode plasma enhanced chemical vapor deposition method, plasma assisted chemical vapor deposition technology, etc. The hardness of a-C film prepared by using the CVD technology at low temperature is low (10 GPa-19 GPa); the a-C film prepared by using the PVD process has high stress, so that the thickness of the a-C film is limited. For a-C film with a hardness greater than 40 GPa, the thickness is generally less than 5 μm. Therefore, the preparation of high-quality, super-thick ta-C film cannot be realized so far, which limits the application range and industrial development of carbon film in the industries of aviation, petroleum, etc.

[0004] Scientists in the United Kingdom, etc. prepared a-C film with a hardness of 68 GPa by using FCVA, but the thickness was only 3 μm; scientists in Japan, etc. prepared super-thick carbon film by using plasma immersion or CVD technology, and the film layer thickness can be as high as 400 μm, but the hardness is only 13 GPa. Therefore, it is a bottleneck problem for the carbon film preparation technology to simultaneously meet the requirements of high hardness and large thickness.

[0005] Stress is the internal force generated between the parts of the object when the object deforms due to external causes (force, humidity, temperature field change, etc.), hardness is the ability of the material to resist the pressure of hard objects into its surface, from the physical definition, stress and hardness are a pair of symbiotic quantities, and it is contradictory to want high hardness and low stress. High hardness of carbon film is often accompanied by high stress, and high stress is the main reason for film peeling, how to reduce the internal stress while maintaining high hardness has always been a difficult point, and the stress of the high hardness film prepared by the prior art is more than 3Gpa, and peeling under high stress is normal.

[0006] Therefore, it is an urgent problem for those skilled in the art to provide a diamond-like film with high hardness and large thickness and a preparation method thereof. SUMMARY

[0007] Therefore, the present application provides an ultra-thick diamond-like film prepared by a double pulse technology, which can maintain high hardness while reducing internal stress, so that the film does not peel off at a large thickness.

[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0009] A preparation method for preparing an ultra-thick diamond-like film by a double pulse technology, the method comprising the following steps:

[0010] An amorphous carbon film is formed by treating with a pulse magnetic field and a pulse electric field during deposition of carbon atoms on the surface of a sample.

[0011] Preferably, the process parameters of the pulse magnetic field are: current is 10-100A, instantaneous magnetic field strength is 10-300mT, and frequency is 10-100Hz.

[0012] The present application limits the pulse magnetic field strength to 10-300mT, and the angle between the magnetic field direction generated by the pulse magnetic field and the plasma extraction direction is 60-90°. Under the action of the pulse magnetic field, the arc spot movement speed is increased by more than 3 times, to 10-50m / s. At the increased speed, the surface residence time is greatly reduced, the micro-area temperature is greatly reduced, and the problems such as particle ejection caused by high temperature are significantly reduced, and the film layer density is improved. Under the driving of the pulse magnetic field, the arc spot movement range is greatly increased, the target material utilization efficiency is improved, and the area of the extracted plasma is also increased, improving the uniformity of film formation.

[0013] Preferably, the process parameters of the pulse electric field are: voltage is 10-50kV, instantaneous power can be 1MW, pulse width is 1-5us, and frequency is 10-1000Hz.

[0014] In the technical scheme of the present application, the film layer obtains instantaneous high energy under the action of the pulse electric field, high-energy carbon ion beam injection occurs under the action of the high energy, the injection depth is 10-50 nm, scattering and defects also occur; the high-energy carbon injection has the maximum energy loss near the range, high temperature is generated in the energy loss process, i.e. micro-area high temperature; the micro-area high temperature can release local internal stress, promote the local sp 3 The sp 2 The related high-energy carbon ion injection can realize local micro-area stress release while maintaining the hardness of the overall carbon film, which solves the problem of high hardness and organic fusion of the super-thick film; the pulse width of 1-5 mu s can ensure the stress release of the local micro-area, and it is difficult to realize the local stress release when the pulse width is less than 1 mu s; when the pulse width is greater than 5 mu s, the local range is too large, the stress release is too much, and the overall hardness of the film layer decreases.

[0015] Preferably, the arc current of the carbon atom is 50-120 A.

[0016] Preferably, the target material of the carbon atom is a carbon target, the thickness of the carbon target is 20-40 mm, and the diameter is 100-200 mm.

[0017] Preferably, the current intensity of the sample surface is 200-400 mA, and the deposition temperature is not higher than 80 DEG C.

[0018] Preferably, the sample is subjected to ultrasonic cleaning before deposition.

[0019] Preferably, the process parameters of the ultrasonic cleaning are as follows: the ultrasonic power is 30-80 W, the frequency is 10-100 Hz, the water temperature is 70 DEG C, and the cleaning time is 30-90 min.

[0020] The super-thick diamond-like film prepared by the preparation method described above.

[0021] Preferably, the thickness of the super-thick diamond-like film is 20-80 mu m, and the hardness is 6000-9800 HV.

[0022] Preferably, the super-thick diamond-like film is applied in the aviation, petroleum and other industries.

[0023] As can be seen from the above technical scheme, compared with the prior art, the present application has the following beneficial effects:

[0024] 1. The carbon film prepared by the double pulse technology of the present application has high bonding strength with the substrate (the critical load of the scratch is greater than 30 N), and can maintain excellent performance for a long time under different service environments;

[0025] 2. The technical scheme of the present application is different from the traditional technology, the surface ablation of the carbon target material can be conveniently and accurately adjusted by the double pulse technology, and the service life of the target material is greatly improved;

[0026] 3, The carbon film layer prepared by the double pulse technology has high density, sp 3 and sp 2 The structure can be conveniently proportionally controlled;

[0027] 4, The double pulse technology can realize good uniformity of the large-area film layer (more than 200mm).

[0028] 5, The double pulse technology can finally realize the perfect combination of high hardness and super thickness. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. The drawings in the description are only embodiments of the present application.

[0030] Figure 1 A process flow chart of the super-thick diamond-like carbon film prepared by the double pulse technology of the present application;

[0031] Figure 2 An effective width chart of the product film uniformity within 10% prepared by embodiments 1-5 of the present application;

[0032] Figure 3 A carbon film thickness line chart of the product prepared by embodiments 1-5 of the present application;

[0033] Figure 4 A carbon film hardness comparison chart of the product prepared by embodiments 1-5 of the present application. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0035] Embodiment 1

[0036] As Figure 1 , the present application provides a super-thick diamond-like carbon film prepared by the double pulse technology, and the specific steps are as follows:

[0037] (1) Ultrasonic cleaning of 304 stainless steel sample

[0038] The sample is cleaned by using an ultrasonic cleaning device, the ultrasonic power is 50W, the power is 50Hz, the water temperature is 70℃, and the cleaning time is 30min;

[0039] (2) The sample is loaded into a vacuum chamber and vacuumized

[0040] After the sample is cleaned, the sample is dried by nitrogen, is moved into a vacuum chamber, the vacuum chamber is vacuumized by a mechanical pump and a molecular pump, the vacuum is extracted to 1*10 -3 Pa;

[0041] (3) Start the arc power supply

[0042] The sample is rotated to the arc source outlet, and the arc power supply is started; the carbon target of the arc source cathode target has a thickness of 20 mm and a diameter of 100 mm; the starting arc current is 80 A, the sample workpiece surface current intensity is 300 mA, and the deposition temperature is not higher than 80 DEG C;

[0043] (4) Start the pulse magnetic field

[0044] The pulse magnetic field is started, the magnetic field intensity is 100 mT, the pulse magnetic field current is 60 A, the frequency is 60 Hz, and the angle between the pulse magnetic field direction and the carbon atom extraction direction is 60-90 DEG;

[0045] (5) Start the pulse electric field

[0046] The pulse electric field is started, the pulse electric field voltage is 15 kV, the instantaneous power is 1 MW, the pulse width is 1 mu s, and the frequency is 100 Hz;

[0047] The deposition time is 4 h, and the sample with amorphous carbon film is prepared.

[0048] Example 2

[0049] The application provides a super-thick diamond-like film prepared by using a double pulse technology, wherein the pulse magnetic field current is 80 A, the frequency is 80 Hz, the pulse electric field voltage is 15 kV, the pulse width is 1 mu s, and the frequency is 100 Hz; the rest of the parameters and conditions are completely same as those in example 1.

[0050] Example 3

[0051] The application provides a super-thick diamond-like film prepared by using a double pulse technology, wherein the pulse magnetic field current is 85 A, the frequency is 85 Hz, the pulse electric field voltage is 15 kV, the pulse width is 0.5 mu s, and the frequency is 100 Hz; the rest of the parameters and conditions are completely same as those in example 1.

[0052] Example 4

[0053] The application provides a super-thick diamond-like film prepared by using a double pulse technology, wherein the pulse magnetic field current is 90 A, the frequency is 90 Hz, the pulse electric field voltage is 15 kV, the pulse width is 10 mu s, and the frequency is 100 Hz; the rest of the parameters and conditions are completely same as those in example 1.

[0054] Example 5

[0055] The application provides a super-thick diamond-like film prepared by a double pulse technique, wherein a pulse magnetic field current is 100 A, a frequency is 100 Hz, a pulse electric field voltage is 15 kV, a pulse width is 1 mu s, and the frequency is 100 Hz; and the rest of parameters and conditions are completely same as those in example 1.

[0056] Example 6

[0057] The application provides a super-thick diamond-like film prepared by a double pulse technique, wherein a pulse magnetic field current is 100 A, a frequency is 100 Hz, a pulse electric field voltage is 15 kV, a pulse width is 5 mu s, and the frequency is 100 Hz; and the rest of parameters and conditions are completely same as those in example 1.

[0058] The relevant products prepared in examples 1-6 are detected and analyzed, wherein,

[0059] As Figure 2 The effective width chart of the film forming uniformity of the products prepared in examples 1-6 is shown in the figure, and the effective width of the film forming of examples 1-6 is 165 mm, 176 mm, 192 mm, 198 mm, 196 mm and 190 mm respectively, it can be seen that the film forming uniformity range is obviously increased with the increase of the pulse magnetic field current and frequency, compared with example 1, the uniformity range can be increased by 20% at most;

[0060] As Figure 3 The carbon film thickness line chart of the products prepared in examples 1-6 is shown in the figure, and the film thickness of examples 1-6 is 52 mu m, 53 mu m, 8 mu m, 86 mu m, 51 mu m and 69 mu m respectively, it can be seen that the film thickness is obviously increased with the increase of the pulse electric field pulse width, compared with example 3, the thickness of example 4 is more than 10 times;

[0061] As Figure 4 The comparison chart of the carbon film hardness of the products prepared in examples 1-6 is shown in the figure, and the hardness of examples 1-5 is 82 GPa, 81 GPa, 86 GPa, 46 GPa, 83 GPa and 82 GPa respectively, it can be seen that the film forming hardness is not obviously increased between 1-5 mu s of the electric field pulse width; the hardness is slightly increased when the pulse width is reduced to 1 mu s or less, but the highest thickness of the film layer is obviously decreased; the hardness is obviously decreased to 46 GPa when the pulse width is increased to more than 5 mu s.

[0062] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an ultra-thick diamond-like carbon film using a double pulse technique, characterized by, The method comprises the following steps: The amorphous carbon film is formed by sequentially using a pulsed magnetic field and a pulsed electric field to treat during deposition of carbon atoms on the surface of a sample; The process parameters of the pulsed magnetic field are as follows: current is 10-100 A, instantaneous magnetic field intensity is 10-300 mT, and frequency is 10-100 Hz; the angle between the direction of the pulsed magnetic field and the direction of the carbon atom extraction is 60-90°; The process parameters of the pulsed electric field are as follows: voltage is 10-50 kV, instantaneous power is 1 MW, pulse width is 1-5 μs, and frequency is 10-1000 Hz.

2. The method of claim 1, wherein the ultra thick diamond like carbon film is prepared by a double pulse technique. The arc current of the carbon atoms is 50-120 A.

3. The method of claim 1, wherein the ultra thick diamond like carbon film is prepared by a double pulse technique. The target material of the carbon atoms is a carbon target, the thickness of the carbon target is 20-40 mm, and the diameter of the carbon target is 100-200 mm.

4. The method of claim 1, wherein the ultra thick diamond like carbon film is prepared by a double pulse technique. The current intensity of the surface of the sample is 200-400 mA, and the deposition temperature is not higher than 80 ℃.

5. The method of claim 1, wherein the ultra thick diamond like carbon film is prepared by a double pulse technique. The sample is subjected to ultrasonic cleaning before deposition.

6. The method of claim 5, wherein the ultra thick diamond like carbon film is prepared by a double pulse technique. The process parameters of the ultrasonic cleaning are as follows: ultrasonic power is 30-80 W, frequency is 10-100 Hz, water temperature is 70 ℃, and cleaning time is 30-90 min.

7. The super-thick diamond-like film prepared by the preparation method in any one of claims 1-6.

8. The ultra thick diamond like film according to claim 7, wherein, The thickness of the super-thick diamond-like film is 20-80 μm, and the hardness is 6000-9800 HV.

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