WO2019119646A1

WO2019119646A1 - Method for improving binding force and tribological property of fullerene-like thin film

Info

Publication number: WO2019119646A1
Application number: PCT/CN2018/077978
Authority: WO
Inventors: 张俊彦; 高凯雄; 张斌; 王永富; 强力
Original assignee: 中国科学院兰州化学物理研究所
Priority date: 2017-12-21
Filing date: 2018-03-05
Publication date: 2019-06-27
Also published as: CN108149217A

Abstract

Provided is a method for improving the binding force and tribological property of a fullerene-like thin film, comprising: 1) cleaning a substrate; 2) loading a sample; 3) evacuating and re-cleaning; and 4) depositing a fullerene-like thin film. The method uses a plasma-enhanced chemical vapor deposition technique, wherein nitrogen, phosphine and methane are used as gas sources, and the fullerene-like thin film is deposited onto a substrate under the combined action of a radio frequency power source and a pulsed negative bias. The process of the method is simple, economic and efficient, the deposition temperature is low, the repeatability is good, the friction coefficient is extremely low, the improvement in the binding force of the substrate to the fullerene-like thin film is obvious, and the binding force and tribological property of the fullerene-like thin film can thus be substantially improved. The method is applicable to a substrate such as a stainless steel surface, a ceramic, a high polymer material and a composite material, and has broad application prospects.

Description

Method for improving adhesion and tribological properties of fullerene-like films

Technical field

The invention belongs to the field of plasma enhanced chemical vapor deposition and relates to a method for improving the adhesion and tribological properties of a fullerene-like film.

Background technique

With the high precision, high integration, high energy efficiency and high reliability development of mechanical systems, the surface effects and interface effects of moving parts of mechanical systems are becoming more and more prominent, and the control requirements for friction and wear performance are becoming more and more demanding. The annual losses due to friction and wear in developed countries account for about 5%-7% of gross national product (GDP). China is a big manufacturing country with a higher proportion of losses. According to incomplete statistics, the annual economic losses caused by friction and wear in China have reached trillions of yuan. Compared with industrial developed countries, China's mechanical equipment has a short service life and huge waste of resources and energy. According to the statistics of 2012, China's energy consumption per unit of GDP is seven times that of Japan, 3.3 times that of the United States, and 2.5 times the world average. Reducing friction and wear of mechanical moving parts has been recognized as one of the ways to effectively extend its working life and improve the reliability and stability of its operation. The solid ultra-slip film and technology is a big leap in the development of tribology. It is the new high point of research and application of solid lubricating materials. It is the key technology to solve the high energy consumption of high-tech cutting technology, break through the long life and stability of equipment, and reduce equipment energy. Consumption and resource consumption. The fullerene-like film has a combination of high hardness, high modulus of elasticity, good chemical inertness, low friction coefficient, strong abrasion resistance, and excellent electrical properties, and is suitable as a protective coating. Moreover, the fullerene-like film can be deposited on the surface of various substrates at relatively low temperatures, and thus has broad application prospects in the fields of electrochemistry, mechanics, tribology, nuclear energy, aerospace and the like.

However, there has always been a major problem in the development and application of fullerene-like films. The adhesion between the fullerene-like film and the metal substrate is poor, it is easy to fall off from the metal substrate, and the friction coefficient is not particularly low, which is very The promotion and application of fullerene-like films are limited to a large extent. The other reason for the weak bonding is that the film generates extremely high stress during the preparation process, and the film itself is chemically inert, making it difficult to form a chemical bond with the metal substrate; and, as the thickness of the film increases, The bonding strength of the film to the metal substrate is lowered. There are many methods for preparing fullerene-like films, and how to enhance the adhesion of metal substrates to fullerene-like films and reduce friction is a key issue. At present, scientists and industrialists in various countries have tried to increase the bonding force between the carbon film and the steel substrate by adding a gradient transition layer (patent ZL 200910098622.1), but the method is complicated and the effect of improving the bonding force is not obvious. In addition, the deposited fullerene-like film has a high coefficient of friction (patent ZL 200710308591.9).

At present, everyone is concerned about the preparation of fullerene-like films, which do not improve the fullerene-like films by doping elements.

In summary, the preparation of the fullerene film and its universalization have important scientific significance and application prospects.

Summary of the invention

It is an object of the present invention to provide a method for improving the adhesion and tribological properties of a fullerene-like film.

The invention utilizes a plasma enhanced chemical vapor deposition method to dope N element and P element into a fullerene-like film, and the fullerene-like film has high hardness, high elastic modulus, good chemical inertness, low friction coefficient and anti-wear. The comprehensive properties such as strong properties and excellent electrical properties are further improved, which can effectively improve the bonding force between the film and the substrate, and further improve the tribological properties. Moreover, the method has the advantages of simple equipment, low deposition temperature, good repeatability, and extremely low friction coefficient, and the adhesion between the substrate and the fullerene-like film is improved.

A method for improving the adhesion and tribological properties of a fullerene-like film, characterized in that the specific steps are:

1) Cleaning the substrate

The pre-cleaned substrate is ultrasonically washed in acetone and ethanol for 20 to 40 minutes, and then dried by washing the ear;

2) Loading the sample

Transferring the cleaned sample to a vacuum chamber, placed on a lower substrate tray, and the substrate tray is connected to a pulsed negative bias power source;

3) Vacuum and clean again

The mechanical pump, the Roots pump and the molecular pump are used to sequentially evacuate the chamber until the vacuum in the chamber is less than 1.0×10 ^-3 Pa; the molecular pump is turned off, the argon gas is introduced into the chamber, and the pulse bias is -700 to -500 V, Plasma cleaning is carried out for 30 minutes under a condition of a duty ratio of 50 to 70% to remove impurities and contaminants remaining on the surface;

4) Deposited fullerene film

A mixed gas of nitrogen, phosphine and methane is introduced, and the film is deposited for 1 to 3 hours under the conditions of a pulse bias of -700 to -400 V, a deposition pressure of about 20 to 50 Pa, and a duty ratio of 50 to 60%. Both the diameter and the height are 200 to 450 mm, and the diameter of the upper plate and the diameter of the lower plate are 200 to 500 mm, and the distance between them is about 30 to 100 mm.

The volume flow rate of the argon gas in the step 3) is 50 to 280 SCCM.

The volume flow rate of the nitrogen gas, the phosphine gas, and the methane in the step 4) is 20 to 50 SCCM, 10 to 30 SCCM, and 5 to 30 SCCM, respectively.

The power supplies used are RF power and pulsed power instead of conventional single RF power. In this system, the RF power supply can control the density of the plasma, the DC negative bias can control the energy of the plasma, and the pulse power supply can reduce the internal stress generated by the fullerene-like film. The combination of the three has achieved excellent results.

The substrate is stainless steel, ceramic, polymeric material or composite material.

The invention utilizes plasma enhanced chemical vapor deposition technology to deposit a fullerene film co-doped with N and P elements on the substrate, and the method has the advantages of simple process, high economic efficiency, low deposition temperature and good repeatability. It can greatly improve the bonding force and tribological properties of the fullerene-like film, and make the fullerene-like film have better lubrication effect. Therefore, the invention has a wide range of applications and plays an important role in various substrate surfaces requiring lubrication.

The binding force and tribological properties of the substrate of the present invention and the fullerene-like carbon film are greatly improved, and the working life of the fullerene-like film under high-intensity working conditions is improved.

DRAWINGS

Figure 1 is a graph showing the friction coefficient of a fullerene-like film co-doped with N and P elements and a raw fullerene film.

Figure 2 is a graph showing the binding force of a fullerene-like film co-doped with N and P elements and a raw fullerene film.

Detailed ways

The present invention proposes a method for improving the adhesion and tribological properties of a fullerene-like film, and the present invention will be further described below.

Example 1:

First, select three pieces of stainless steel with smooth surface, pre-clean with dilute hydrochloric acid solution, wait for it to dry, then put it into acetone and ethanol for ultrasonic cleaning for 30 minutes, take out the stainless steel piece, dry it with ear-washing ball and quickly transfer it. On the vacuum chamber substrate, vacuuming begins. Next, when the vacuum is drawn to less than 1.0×10 ^-3 Pa, argon gas (150 SCCM) is introduced, the gas pressure is adjusted to about 25 Pa, and the plasma is cleaned under the pulse bias of -600 V and the duty ratio is 50%. , lasts for 30 minutes. After the cleaning is completed, a mixed gas of nitrogen (30 SCCM), phosphine (10 SCCM) and methane (10 SCCM) is introduced, and the gas pressure is adjusted to about 35 Pa, and the temperature is lowered at a pulse bias of -500 V and a duty ratio of 50%. A fullerene film was deposited and deposited for 2 hours.

Example 2:

First, two wafers with a smooth surface were selected. One surface was deposited with a fullerene film co-doped with N and P elements, and the other surface was deposited with a fullerene film not doped with N and P elements. The two silicon substrates on which the carbon film was deposited were then subjected to a rubbing test. The test conditions were as follows: a dual ball 6 mm steel ball with a load of 10 N, a frequency of 3 Hz, an amplitude of 5 mm, and a time of 1 hour. As shown in Fig. 1, the average coefficient of friction of the fullerene film co-doped with N and P elements is 0.012, and the average coefficient of friction of the fullerene film not doped with N and P elements is 0.021. Three experiments were repeated to ensure the accuracy of the experimental results, indicating that the fullerene film co-doped with N and P elements can greatly reduce the friction and reduce the friction by about 43%.

Example 3:

First, two stainless steel sheets with a smooth surface were selected. One surface was deposited with a fullerene film co-doped with N and P elements, and the other surface was deposited with a fullerene film not doped with N and P elements. The two silicon substrates on which the carbon film was deposited were then subjected to a scratch test. As shown in FIG. 2, the fullerene film co-doped with N and P elements has a bonding force of 40 N, and the fullerene film without N and P elements has a bonding strength of 10 N. Three experiments were repeated to ensure the accuracy of the experimental results, indicating that the fullerene film co-doped with N and P elements can improve the adhesion of the substrate to the fullerene-like film and increase the bonding force by 300%.

Claims

A method for improving the adhesion and tribological properties of a fullerene-like film, characterized in that the specific steps are:

1) Cleaning the substrate

The pre-cleaned substrate is ultrasonically washed in acetone and ethanol for 20 to 40 minutes, and then dried by washing the ear;

2) Loading the sample

Transferring the cleaned sample to a vacuum chamber, placed on a lower substrate tray, and the substrate tray is connected to a pulsed negative bias power source;

3) Vacuum and clean again

The mechanical pump, the Roots pump and the molecular pump are used to sequentially evacuate the chamber until the vacuum in the chamber is less than 1.0×10 -3 Pa; the molecular pump is turned off, the argon gas is introduced into the chamber, and the pulse bias is -700 to -500 V, Plasma cleaning for 30 minutes under a condition of a duty ratio of 50 to 70%;

4) Deposited fullerene film

A mixed gas of nitrogen, phosphine and methane is introduced, and the film is deposited for 1 to 3 hours under the conditions of a pulse bias of -700 to -400 V, a deposition pressure of about 20 to 50 Pa, and a duty ratio of 50 to 60%. Both the diameter and the height are 200 to 450 mm, and the diameter of the upper plate and the diameter of the lower plate are 200 to 500 mm, and the distance between them is about 30 to 100 mm.
The method of claim 1 wherein said argon gas has a volumetric flow rate of from 50 to 280 SCCM in step 3).
The method according to claim 1, wherein the volume flow rate of the nitrogen gas, the phosphine gas, and the methane in the step 4) is 20 to 50 SCCM, 10 to 30 SCCM, and 5 to 30 SCCM, respectively.
The method of claim 1 wherein the power source used is a radio frequency power source and a pulse power source.
The method of claim 1 wherein said substrate is stainless steel, ceramic, polymeric material or composite material.