CN111647852A

CN111647852A - Solid lubricating film and preparation method and application thereof

Info

Publication number: CN111647852A
Application number: CN202010622451.4A
Authority: CN
Inventors: 王晓飞; 许佼; 李玉磊; 邬苏东; 任富增; 赵予生
Original assignee: Southwest University of Science and Technology
Current assignee: Southwest University of Science and Technology; Southern University of Science and Technology
Priority date: 2020-06-30
Filing date: 2020-06-30
Publication date: 2020-09-11

Abstract

The invention discloses a solid lubricating film and a preparation method and application thereof. The solid lubricating film comprises MoS₂A multi-layered structure film formed by alternately connecting layers and Mo-S-N composite layers, wherein the MoS₂The thickness of the layer and the Mo-S-N composite layer are both nano-scale thickness, and the Mo-S-N composite layer is N-doped MoS₂And (4) compounding layers. MoS of nanometer-scale thickness in the solid lubricating film of the invention₂The layers and Mo-S-N composite layers are alternately stacked to obtain nano-scaleThe obtained solid lubricating film is vacuum lubricating with excellent performances such as high strength, low friction, long service life and the like, and the cooperative optimization of the mechanical property and the lubricating property of the transition metal disulfide-based solid lubricating film is effectively realized.

Description

Solid lubricating film and preparation method and application thereof

Technical Field

The invention relates to the technical field of composite materials, relates to a solid lubricating film, a preparation method and application thereof, and particularly relates to a transition metal disulfide-based solid lubricating film, a preparation method and application thereof.

Background

With the rapid development of high and new technology industries such as precision machinery, aerospace, and microelectronics, the development of solid lubricating film materials and technologies in extremely harsh environments becomes a hot spot of competitive research in various countries in the world. The solid lubricating film material is mainly characterized in that a layer of substance with completely different properties and performances from the whole material is deposited or prepared on the surface, and the tribological performance of the surface of the material is effectively changed without changing the whole material, so that the use requirements of different application occasions are met. Sputtering MoS in a plurality of solid lubricating film materials₂Films have been of interest because of their unique structure and excellent tribological properties. But in the atmosphere, especially in humid air, MoS₂Is easy to be oxidized, leads to the change of the chemical composition and the structure of the film, and reduces and even loses the lubricating property. Simultaneously, sputtering MoS₂The thin film also has the problems of low hardness, weak bearing capacity, poor film-base binding force, difficult ground storage and the like, thereby limiting the application of the thin film.

In order to solve the above problems, many research groups have conducted highly effective research work, which has prompted the development of thin film materials from single-layer, single-component to composite, gradient, and multi-layer. The tribology theory and practice show that the multilayer composite film with high strength, high toughness, superior controllable preparation performance and rich optimization schemes has excellent tribology performance, and is providing feasible schemes for more and more tribology designs of motion mechanisms. For example, CN 102994947A discloses a diamond-like composite molybdenum disulfide nano multilayer film and a preparation method thereof,adopting a double-target magnetron sputtering technology to alternately deposit single diamond-like carbon (DLC) layers and MoS layers with the thickness of 10-100 nm on a stainless steel substrate₂Layer, at the same time solve MoS₂The soft film has poor wear resistance and the diamond-like hard film has large brittleness. MoS₂Although the hardness of the film can be effectively improved by DLC multilayer compounding, the abrasion rate of a DLC hard layer in a vacuum environment is high, so that the vacuum abrasion-resistant service life of the multilayer composite film is still difficult to meet the requirement of more than or equal to 105 turns. CN 110965015A discloses a CrN/MoS₂The solid self-lubricating composite membrane adopts a CrMoN composite membrane treated by low-temperature ion sulfurization to synthesize CrN/MoS with excellent tribological performance in situ₂The solid self-lubricating composite membrane has limited thickness of the sulfurizing layer obtained by the method, and the composite membrane has complex phase structure and is difficult to regulate and control.

Therefore, it is very important to develop a multilayer composite lubricating coating with simple deposition process, compact film structure, low friction coefficient in vacuum environment and good wear resistance.

Disclosure of Invention

In view of the above problems in the prior art, the present invention aims to provide a solid lubricant film, a preparation method and a use thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a solid lubricating film comprising a solid lubricating film composed of MoS₂A multi-layered structure film formed by alternately stacking layers and Mo-S-N composite layers, the MoS₂The thickness of the layer and the Mo-S-N composite layer are both nano-scale thickness, and the Mo-S-N composite layer is N-doped MoS₂And (3) a base composite layer.

In the present invention, the "multi-layer" is at least two layers.

MoS of nanometer-scale thickness in the solid lubricating film of the invention₂The layers and the Mo-S-N composite layers are alternately stacked to obtain a nano-scale or micron-scale multilayer structure film, the obtained solid lubrication film has a compact structure, particularly vacuum lubrication with excellent performances such as high strength, low friction, long service life and the like, and the mechanical properties and the service life of the transition metal disulfide-based solid lubrication film are effectively realizedSynergistic optimization of lubricating properties.

The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.

Preferably, the number of layers of the multilayer structure film is at least two, for example, 3, 4, 6, 7, 8, 10, 12, 15, 17, 18, 20, 30, 45, 60, 75, 85, 110 or 115 layers, and the like, and the specific number of layers may be determined according to the thickness of the multilayer structure film and MoS₂The individual layer thicknesses of the layers and the Mo-S-N composite layer are adjusted.

Preferably, the multilayer structure film has a thickness of 1 μm to 3 μm, such as 1 μm, 1.2 μm, 1.3 μm, 1.5 μm, 1.6 μm, 1.8 μm, 2 μm, 2.3 μm, 2.5 μm, or 3 μm, and the like.

Preferably, said MoS is a single-chip, or multi-chip device₂The individual layer thicknesses of the layer and the Mo-S-N composite layer are independently 6nm to 30nm, such as 6nm, 8nm, 9nm, 12nm, 15nm, 18nm, 20nm, 25nm, 27nm, or 30nm, etc., and if the thickness is less than 6nm, a reduction in mechanical properties of the composite multilayer film may result; if the thickness is more than 30nm, the excellent vacuum lubricating property and mechanical property of the composite multilayer film are difficult to be considered; preferably 9nm to 15 nm.

Preferably, the doping amount of the N element in the Mo-S-N composite layer is 1 at.% to 10 at.%, such as 1 at.%, 2 at.%, 3 at.%, 4 at.%, 5 at.%, 6 at.%, 8 at.%, or 10 at.%, etc., with a preferred doping amount being 4 at.% to 6 at.%. Within the preferable range, the vacuum lubricating property and the mechanical property of the composite multilayer film can be better considered.

As a preferable embodiment of the solid lubricating film of the present invention, the solid lubricating film is supported on a substrate, and the substrate is preferably a steel material.

Preferably, a Ti transition layer is further arranged between the substrate and the solid lubricating film.

In a second aspect, the present invention provides a method for producing a solid lubricating film according to the first aspect, comprising the steps of:

by using MoS₂The target material is formed by alternately forming MoS on the surface of a substrate by changing the deposition atmosphere by using a reactive magnetron sputtering method₂And (4) forming a layer and a Mo-S-N composite layer to obtain the solid lubricating film.

In the present invention, MoS may be formed on the surface of the substrate first₂Layers, then sequentially and alternately forming Mo-S-N composite layers and MoS₂A layer; or a Mo-S-N composite layer can be formed on the surface of the substrate, and then MoS can be formed in turn₂Layers and Mo-S-N composite layers. The skilled person can select as desired.

Through research and analysis of the inventor, the MoS is innovatively proposed₂The target is a magnetron sputtering target material, and the deposition atmosphere is changed (for example, N is periodically introduced into a vacuum chamber)₂Method of reacting gas) to prepare MoS, a composite/multilayer integrated vacuum solid lubricating film, using only a single target material₂The thicknesses of the layer and the Mo-S-N composite layer are both nano-scale thicknesses, and the total thickness of the layer and the Mo-S-N composite layer can reach micron-scale thickness through deposition, so that the micro-nano structure is obtained.

By optimizing the modulation period of the nano-multilayer thin film (i.e., MoS)₂The sum of the single-layer thicknesses of the lubricating layer and the Mo-S-N composite layer), the N doping content, the single-layer film thickness and other key structural parameters, so that the vacuum lubricating MoS with excellent performances such as high strength, low friction, long service life and the like is obtained₂the/Mo-S-N nano multilayer film effectively realizes the synergistic optimization of the mechanical property and the lubricating property of the transition metal disulfide-based solid lubricating film. The modulation period refers to a layer of MoS₂The sum of the thicknesses of the layer and the Mo-S-N composite layer adjacent to the layer.

The method adopts a reactive magnetron sputtering method, and does not relate to multi-target magnetron sputtering and complex radio frequency power supply power control and target baffle switch control. By regulating and controlling the modulation period and N of the multilayer film₂Flow rate, regulation and control of chemical structure parameters of the film, simplification of the preparation method of the composite/multilayer integrated film, and consideration of MoS₂Low friction and low bearing property, high bearing and low friction performance of the Mo-S-N composite layer, controllable mechanical strength and vacuum lubricating property of the material, and capability of meeting vacuum requirementThe best material for the lubrication protection requirement of the environmental bearing mechanical parts on the grinding pair.

Preferably, the method further comprises forming MoS₂And preparing a Ti transition layer on the surface of the substrate before the layer and the Mo-S-N composite layer.

Preferably, the method for preparing the Ti transition layer comprises the following steps: and carrying out magnetron sputtering by adopting a Ti target.

As a preferred technical scheme of the method, MoS is alternately formed on the surface of the substrate₂The method of layer and Mo-S-N composite layer comprises:

(1) by using MoS₂Performing magnetron sputtering on the target material, and depositing the substrate under the condition of introducing working gas and nitrogen source gas to prepare a Mo-S-N composite layer;

(2) continuing to introduce working gas, stopping introducing nitrogen source gas, depositing the substrate, and preparing MoS₂A layer;

(3) sequentially repeating the step (1) and the step (2) until the preset thickness of the solid lubricating film is reached;

alternatively, MoS is alternately formed on the surface of the substrate₂The method of layer and Mo-S-N composite layer comprises:

(1') use of MoS₂Performing magnetron sputtering on the target material, depositing the substrate under the condition of introducing working gas, and preparing MoS₂A layer;

(2') continuously introducing working gas and nitrogen source gas to deposit the substrate to prepare a Mo-S-N composite layer;

(3') repeating the step (1') and the step (2') in sequence until a predetermined thickness of the solid lubricating film is reached.

In the method of the present invention, it is preferable that the Mo-S-N composite layer is formed on the substrate first, and the last layer deposited, that is, the outermost layer of the solid lubricating film is MoS₂And (3) a layer. The preferable scheme can exert the excellent vacuum lubrication performance and mechanical performance to a greater extent.

Preferably, the working gas is Ar.

Preferably, the nitrogen source gas is N₂Preferably normal N with the purity of more than or equal to 99.999 percent₂。

Preferably, in the step (1) and the step (2'), the flow rate ratio of the working gas and the nitrogen source gas is 40sccm (2sccm-10sccm), such as 20:1, 18:1, 16:1, 15:1, 13:1, 10:1, 9.5:1, 9.2:1, 9:1, 8.5:1, 8:1 or 7:1, etc., and if the flow rate of the nitrogen source gas is too large, the lubricating property of the Mo-S-N composite layer is deteriorated; if the flow rate of the nitrogen source gas is too small, the Mo-S-N composite layer has insignificant effect on improving the mechanical performance of the thin film, and preferably 40sccm (2sccm-6 sccm).

Preferably, in step (1) and step (2'), the temperature of the deposition is 150 ℃ to 250 ℃, such as 150 ℃, 160 ℃, 180 ℃, 190 ℃, 200 ℃, 215 ℃, 230 ℃, 240 ℃ or 250 ℃, etc.

Preferably, the substrate is subjected to a cleaning treatment before use, the cleaning treatment comprising ultrasonic cleaning using acetone and alcohol in sequence, followed by drying.

As a further preferred technical solution of the method of the present invention, the method comprises the steps of:

(1) polishing the steel substrate until the surface roughness is less than 50nm, then sequentially using acetone and alcohol to perform ultrasonic cleaning, and then drying;

(2) putting the substrate obtained in the step (1) into a vacuum deposition chamber, vacuumizing, cleaning the substrate by adopting a pulse negative bias power supply, wherein the working gas during cleaning is Ar, and starting deposition after cleaning;

(3) adopting direct current magnetron sputtering Ti target, wherein the working gas is Ar, and preparing a Ti transition layer with the thickness of 150nm-220 nm;

(4) in MoS₂Simultaneously introducing working gas Ar and nitrogen source gas N into the target material₂Preparing a first Mo-S-N composite layer with the thickness of 20nm-50 nm;

(5) continuing to introduce the working gas Ar, stopping introducing the nitrogen source gas N₂Preparing a first layer of MoS with a thickness of 20nm to 50nm₂A layer;

(6) repeating the step (4) and the step (5) to the MoS in sequence₂The total thickness of the layer and the Mo-S-N composite layer is 1-1.5 μm.

The preferred technical scheme provides a method for preparing the nano-particles on the substrateMoS of a surface₂The method of the/Mo-S-N composite/multilayer integrated film adopts MoS₂The target is a target material, and a Ti transition layer and MoS are obtained by sputtering on the substrate which is subjected to surface polishing and cleaning treatment in sequence by a reactive magnetron sputtering method₂And Mo-S-N composite layers are alternately deposited to form a multi-layer structure film. Wherein the Mo-S-N composite layer is a hard layer for enhancing the mechanical property of the film, and the MoS₂The single-phase layer is a soft layer ensuring the lubricating performance of the film. The multilayer composite film has good mechanical property and vacuum wear-resistant antifriction property, can be used as a self-lubricating protective coating of space vacuum environment service equipment (such as a spacecraft solar panel unfolding mechanism and the like), plays roles in improving the reliability of the equipment and prolonging the service life, and has good application value.

In a third aspect, the invention provides the use of the solid lubricating film according to the first aspect for lubrication protection of structural materials of steel (such as 9Cr18, GCr15 and the like) under vacuum service conditions.

Compared with the prior art, the invention has the following beneficial effects:

1. the method adopts a reactive magnetron sputtering method, does not relate to multi-target magnetron sputtering and complex radio frequency power supply power control and target baffle switch control, has simple treatment process, and the prepared multilayer composite structure solid lubricating film has uniform and compact structure, controllable structural components and good self-lubricating performance in a vacuum environment.

2. The multilayer composite structure solid lubricating film prepared by the invention has excellent mechanical property and vacuum lubricating property, and can be widely applied to lubrication protection of 9Cr18 and GCr15 structural materials under vacuum service working conditions.

Drawings

Fig. 1(a) and 1(b) are scanning electron micrographs of the composite multilayer solid lubricating film of example 1, wherein fig. 1(a) is a surface image and fig. 1(b) is a cross-sectional image.

FIG. 2 is a multilayer composite solid lubricating film of example 1, a conventional single component (corresponding to comparative example 1, corresponding to pure MoS in the figure)₂) And a single structure film (corresponding to comparative example 2, corresponding to MoS in the figure)N composite) and elastic modulus.

FIG. 3 is a multilayer composite solid lubricating film of example 1, a conventional single component (corresponding to comparative example 1, corresponding to pure MoS in the figure)₂) And a friction coefficient curve of a single structure film (corresponding to comparative example 2, corresponding to MoSN recombination in the figure) in a vacuum environment.

FIGS. 4(a1) and 4(a2) are comparative example 1 single layer MoS₂Scanning electron micrographs of the films, wherein FIG. 4(a1) is a surface image and FIG. 4(a2) is a cross-sectional image.

Fig. 4(b1) and 4(b2) are scanning electron micrographs of the single-layer MSN film of comparative example 2, in which fig. 4(b1) is a surface image and fig. 4(b2) is a cross-sectional image.

Fig. 4(c1) and 4(c2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 4, in which fig. 4(c1) is a surface image and fig. 4(c2) is a cross-sectional image.

Fig. 4(d1) and 4(d2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 5, in which fig. 4(d1) is a surface image and fig. 4(d2) is a cross-sectional image.

Fig. 4(e1) and 4(e2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 6, in which fig. 4(e1) is a surface image and fig. 4(e2) is a cross-sectional image.

Fig. 5(a1) and 5(a2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 8, in which fig. 5(a1) is a surface image and fig. 5(a2) is a cross-sectional image.

FIGS. 5(b1) and 5(b2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 9, in which FIG. 5(b1) is a surface image and FIG. 5(b2) is a cross-sectional image.

Fig. 5(c1) and 5(c2) are scanning electron micrographs of the multilayer composite solid lubricating film of comparative example 4, in which fig. 5(c1) is a surface image and fig. 5(c2) is a cross-sectional image.

FIG. 6 is a single layer MoS of comparative example 1₂Film and different modulation periods MoS₂Hardness and modulus of elasticity curves for/MSN multilayer films (H54, H27, H15, H9 and H6 correspond to comparative example 3, example 4, example 5, example 6 and example 7, respectively).

FIG. 7 is a single layer MoS of comparative example 1₂Film, comparative example 2 single layer MSN film and different modulation periods MoS₂Coefficient of friction curves for the/MSN multilayer films under high vacuum (H54, H27, H15, H9, and H6 correspond to comparative example 3, example 4, example 5, example 6, and example 7, respectively).

FIG. 8 is a single layer MoS of comparative example 1₂Film and different modulation periods MoS₂Hardness and elastic modulus curves for/MSN multilayer films (

nitrogen flow

0, 4, 6, 10 and 20 correspond to comparative example 1, example 8, example 5, example 9 and comparative example 4, respectively).

FIG. 9 is a single layer MoS of comparative example 1₂Film and different modulation periods MoS₂Coefficient of friction curves for MSN multilayer films under high vacuum conditions (H15-N4, H15-N6, H15-N10, H15-N20 for example 8, example 5, example 9 and comparative example 4, respectively).

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

And (3) testing:

firstly, morphology detection:

and (5) carrying out appearance detection on each sample by adopting a scanning electron microscope.

Secondly, detecting microhardness and elastic modulus:

the press-in hardness and the elastic modulus of the film are tested by adopting a GB/T25898-2010 instrumented nano press-in test method.

Thirdly, detecting the friction coefficient in a vacuum environment:

and (3) detecting the friction coefficient of the sample in a vacuum environment.

In the multilayer composite solid lubricating film obtained in each embodiment of the invention, the Mo-S-N composite layer is directly contacted with the Ti transition layer, and the last layer deposited, namely the outermost layer of the solid lubricating film, is MoS₂And (3) a layer.

The theoretical thickness of the film in each embodiment of the invention is MoS₂The sum of the thicknesses of the single layers of the lubricating layer and the Mo-S-N composite layer.

Example 1

1. Using polished 9Cr18 steel as substrate (surface roughness)<50nm), ultrasonic cleaning with acetone and alcohol, oven drying, placing into vacuum deposition chamber, and locally vacuum-pumping to 1.0 × 10^-3Deposition was started after Pa. Before deposition, a pulse bias voltage source is adopted to carry out negative bias cleaning on the substrate, the pressure of working gas Ar is 0.75Pa, and the cleaning time is 20 min.

2. And (3) preparing a Ti transition layer with the thickness of 200nm by adopting a direct current magnetron sputtering Ti target and working gas Ar of 0.75Pa, and depositing at the temperature of 150 ℃.

3. Simultaneously introducing Ar and N₂Sputtering MoS₂And (3) preparing a first Mo-S-N composite layer (MSN layer for short) by using the target with the gas flow of 40sccm and 4sccm respectively, wherein the working pressure is 0.75Pa, the deposition temperature is 200 ℃, and the deposition thickness is 27 nm.

4. Continuing to introduce Ar with the gas flow of 40sccm and the working pressure of 0.75Pa, and stopping introducing N₂Sputtering of MoS₂Target, depositing a first layer of MoS₂And (3) lubricating layer, deposition temperature is 150 ℃, and deposition thickness is 27 nm.

5. Repeating the steps 3 and 4 in sequence until the Mo-S-N composite layer and the MoS₂The total film thickness of the lubricating layer reached 1.0. mu.m, giving MoS₂the/Mo-S-N composite/multilayer integrated film is called multilayer composite solid lubricating film for short.

Fig. 1(a) and 1(b) are scanning electron micrographs of the composite multilayer solid lubricating film of example 1, wherein fig. 1(a) is a surface image and fig. 1(b) is a cross-sectional image. As can be seen from the figure, the surface of the composite/multilayer integrated film is flat and dense, and the bonding degree of the film and the substrate material is good.

FIG. 2 is a multilayer composite solid lubricating film of example 1, a conventional single component (corresponding to comparative example 1, corresponding to pure MoS in the figure)₂) And microhardness and elastic modulus of single structure film (corresponding to comparative example 2, MoSN recombination in figure), it can be seen from figure that microhardness of composite/multilayer integrated film and pure MoS₂Compared with the MoSN composite film, the MoSN composite film is slightly reduced.

FIG. 3 is a conventional single component (corresponding to) multilayer composite solid lubricating film of example 1Comparative example 1, corresponding to pure MoS in the figure₂) And a friction coefficient curve of a single structure film (corresponding to comparative example 2, corresponding to MoSN recombination in the figure) in a vacuum environment. As can be seen from the figure, the composite/multilayer integrated film has the advantages of long wear life and pure MoS₂Compared with the MoSN composite film, the film is improved by one order of magnitude.

Comparative example 1

This comparative example is a single layer MoS₂A film, the method of preparation of which differs from example 1 in that: steps 3, 4 and 5 are performed with Ar only, and the rest are the same.

Comparative example 2

This comparative example is a single layer MSN film, which was prepared by a method different from example 1 in that: in steps 3, 4 and 5, Ar and N2 gases are introduced at the same time, and the rest are the same.

Example 2

1. Using polished GCr15 steel as substrate (surface roughness)<50nm), ultrasonic cleaning with acetone and alcohol, oven drying, placing into vacuum deposition chamber, and locally vacuum-pumping to 1.0 × 10^-3Deposition was started after Pa. Before deposition, a pulse bias voltage source is adopted to carry out negative bias cleaning on the substrate, the pressure of working gas Ar is 0.75Pa, and the cleaning time is 20 min.

3. Simultaneously introducing Ar and N₂Sputtering MoS₂And (3) preparing a first Mo-S-N composite layer by using the target with the gas flow of 40sccm and 4sccm respectively, wherein the working pressure is 0.75Pa, the deposition temperature is 180 ℃, and the deposition thickness is 27 nm.

5. Repeating the steps 3 and 4 in sequence until the Mo-S-N composite layer and the MoS₂The total film thickness of the lubricating layer reached 1.0. mu.m, giving MoS₂the/Mo-S-N composite/multilayer integrated film.

Example 3

2. And (3) preparing a Ti transition layer with the thickness of 220nm by adopting a direct current magnetron sputtering Ti target and working gas Ar of 0.85Pa, and depositing at the temperature of 150 ℃.

3. Simultaneously introducing Ar and N₂Sputtering MoS₂And (3) preparing a first Mo-S-N composite layer by using the target and gas flow of 40sccm and 5sccm respectively, wherein the working pressure is 0.80Pa, the deposition temperature is 220 ℃, and the deposition thickness is 25 nm.

4. Continuing to introduce Ar with the gas flow of 40sccm and the working pressure of 0.75Pa, and stopping introducing N₂Sputtering of MoS₂Target, depositing a first layer of MoS₂And (3) lubricating layer, wherein the deposition temperature is 150 ℃, and the deposition thickness is 25 nm.

5. Repeating the steps 3 and 4 in sequence until the Mo-S-N composite layer and the MoS₂The total film thickness of the lubricating layer reached 1.50 μm to obtain MoS₂the/Mo-S-N composite/multilayer integrated film.

Example 4

The number of repetitions of steps 3 and 4 was adaptively adjusted to allow Mo-S-N composite layer and MoS except for a nitrogen flow rate of 6sccm₂The total film thickness of the lubricant layer reached 1.35 μm, and the rest was the same as in example 1.

Example 5

The same as in example 4 was repeated except that the thickness in each of steps 3 and 4 was adjusted to 15 nm.

Example 6

The same as in example 4 was repeated except that the thickness in each of steps 3 and 4 was adjusted to 9 nm.

Example 7

The same as example 1 was repeated except that the thickness in each of steps 3 and 4 was adjusted to 6 nm.

Comparative example 3

The procedure was as in example 1 except that the thickness in each of steps 3 and 4 was adjusted to 54 nm.

TABLE 1 Single layer MoS₂Film, single-layer MSN film and MoS with different modulation periods₂Deposition parameter design of/MSN multilayer film

Examples 4-7 MoS was prepared at different modulation cycles (i.e., varying molybdenum sulfide monolayer thickness/MSN monolayer thickness)₂a/MSN multilayer film. FIG. 6 is a single layer MoS of comparative example 1₂Film and different modulation periods MoS₂Hardness and modulus of elasticity curves for/MSN multilayer films (H54, H27, H15, H9 and H6 correspond to comparative example 3, example 4, example 5, example 6 and example 7, respectively). It can be seen from the graph that the hardness of the multilayer film increases and then decreases with the increase of the modulation period, and the hardness of the sample H15 reaches a maximum of 4.13GPa (corresponding to the modulation period of 30nm), while the hardness of the samples H27 and H54 decreases greatly.

FIG. 7 is a single layer MoS of comparative example 1₂Film, comparative example 2 single layer MSN film and different modulation periods MoS₂The friction coefficient curves of the MSN multilayer film under the high vacuum environment (H54, H27, H15, H9 and H6 respectively correspond to comparative example 3, example 4, example 5, example 6 and example 7). The friction coefficient of the film maintains a stable state after being worn in the high vacuum friction environment for a short time, the whole state varies between 0.01 and 0.05. when the modulation period is 18nm and 30nm, the whole floating change of the friction coefficient of the multilayer film is small, the average friction coefficient is about 0.027, and the wear-resistant life can be maintained to be 1.8 × 10⁵The friction coefficient of the multilayer film with the modulation period of 54nm increases along with the increase of the friction time from 0.02 to 0.06, and the wear-resistant life of the multilayer film is about 1.2 × 10⁵And (6) performing circle times. In contrast, the wear life of the multilayer film is significantly shortened at a modulation period of 108nm and is lower than that of pure MoS₂The multilayer film with modulation period of 12nm can show low friction coefficient in short time friction process, and the friction coefficient varies between 0.012 and 0.018, and the wear resistance life is about 6.4 × 10⁴And (7) turning. It says thatThe wear-resisting service life and the low friction coefficient of the film can be prolonged by selecting a proper modulation period (Λ: 18-30 nm).

Example 8

Except that N in step 3₂The flow rate was adjusted to 4sccm, and the rest was the same as in example 5.

Example 9

Except that N in step 3₂The flow rate was adjusted to 10sccm, and the rest of the procedure was the same as in example 5.

Example 10

Except that N in step 3₂The flow rate was adjusted to 2sccm, and the rest of the procedure was the same as in example 5.

Example 11

Except that N in step 3₂The flow rate was adjusted to 8sccm, and the rest of the procedure was the same as in example 5.

Comparative example 4

Except that N in step 3₂The flow rate was adjusted to 20sccm, and the rest was the same as in example 5.

TABLE 2 Single layer MoS₂Film and different nitrogen flow MoS₂Deposition parameter design of/MSN multilayer film

Examples 8-9 and example 5 MoS preparation under different Nitrogen flow conditions₂The MSN multilayer film has the advantages that the compactness of the film is increased along with the increase of the nitrogen flow, and the time required for depositing the same thickness is prolonged. FIG. 8 is a single layer MoS of comparative example 1₂Film and different modulation periods MoS₂Hardness and elastic modulus curves for/MSN multilayer films (

nitrogen flow

0, 4, 6, 10 and 20 correspond to comparative example 1, example 8, example 5, example 9 and comparative example 4, respectively). As can be seen, the same as pure MoS₂Film hardness (0.16GPa) vs MoS₂The hardness of the/MSN multilayer film is improved by more than one order of magnitude. The hardness of the multilayer film tends to increase and then decrease along with the increase of the nitrogen flow, the hardness of the multilayer film changes within the range of 2.26GPa to 10.47GPa, and the nitrogen flow is 4 to 1The hardness is high at 0sccm, and the multilayer film hardness reaches the maximum value of 10.47GPa at a nitrogen flow of 10 sccm.

FIG. 9 is a single layer MoS of comparative example 1₂Film and different modulation periods MoS₂Coefficient of friction curves for MSN multilayer films under high vacuum conditions (H15-N4, H15-N6, H15-N10, H15-N20 for example 8, example 5, example 9 and comparative example 4, respectively). As can be seen, MoS₂The average friction coefficient of the MSN multilayer film is stabilized between 0.021 and 0.028, and when the nitrogen flow is 4sccm, the friction coefficient of the multilayer film is 4.0 × 10⁴The transition began to decrease from 0.01 to 0.003, an ultra-low friction behavior (CoF less than 0.01) occurred, after which the coefficient of friction gradually increased again to 0.035 and at 1.1 × 10⁵The rotating part begins to be stable, and the ultra-low friction (0.003-0.01) state lasts about 6.5 × 10⁴In turn, the overall average coefficient of friction was 0.021. In addition, MoS₂The wear-resisting life of the/MSN multilayer film is obviously longer than that of pure MoS₂The wear life of the thin film is sharply reduced along with the increase of the nitrogen flow, and the wear life of the multilayer film is obviously lower than 6.0 × 10 when the nitrogen flow is 20sccm⁴When the average friction coefficient is 0.028 and the nitrogen flow is 10sccm, the wear-resisting service life of the multilayer film is 1.4 × 10⁵The average friction coefficient is 0.024, the nitrogen flow rate is 4sccm and 6sccm, and the wear-resisting life of the multilayer film can be prolonged to 1.8 × 10⁵In addition, the friction coefficient is relatively stable in the whole friction process.

TABLE 3 different N₂Chemical composition of Mo-S-N composite layer under flow

The invention also studies the effect of the modulation period and different nitrogen flows on the product morphology:

first, the influence of the modulation period on the morphology of the product

FIG. 4(a1) and FIG. 4 (a)2) Is comparative example 1 Single layer MoS₂Scanning electron micrographs of the films, wherein FIG. 4(a1) is a surface image and FIG. 4(a2) is a cross-sectional image. As can be seen, the MoS is a single layer₂The surface of the film is a porous loose worm-shaped structure, and the microstructure of the film is in a porous columnar structure in the thickness direction.

Fig. 4(b1) and 4(b2) are scanning electron micrographs of the single-layer MSN film of comparative example 2, in which fig. 4(b1) is a surface image and fig. 4(b2) is a cross-sectional image. As can be seen from the figure, the surface of the single-layer MSN film is flat and dense, and the microstructure of the single-layer MSN film is in a tightly arranged columnar structure in the thickness direction.

Fig. 4(c1) and 4(c2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 4, in which fig. 4(c1) is a surface image and fig. 4(c2) is a cross-sectional image. As can be seen from the figure, the surface of the multilayer composite solid lubricating film is more single-layer MoS₂The surface of the film tends to be flat and compact, and the nano multilayer structure can effectively prevent the film from growing into a columnar structure in the thickness direction, so that the compactness of the film is improved.

Fig. 4(d1) and 4(d2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 5, in which fig. 4(d1) is a surface image and fig. 4(d2) is a cross-sectional image. As can be seen from the figure, when the modulation period of the nano multilayer structure is increased in the preferred range, the surface and the section of the film can be kept to be a flat and dense morphological structure.

Fig. 4(e1) and 4(e2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 6, in which fig. 4(e1) is a surface image and fig. 4(e2) is a cross-sectional image. As can be seen from the figure, when the modulation period of the nano multilayer structure is reduced in a preferred range, the surface and the section of the film can be kept to be a flat and dense morphological structure.

By combining the above analysis, the MSN composite film and the MoS₂the/MSN multilayer film structure is more compact and consists of fine particle stacks, which shows that the introduction of nitrogen element effectively inhibits MoS₂And (5) growing columnar crystals. In addition, the surface structure of the MSN composite film is relatively more compact and is formed by stacking compact large particles, but MoS₂MSN multilayerThe film surface has a certain amount of microcracks and fine gaps, which provide corresponding channels for gas such as water molecules and oxygen to enter the film along the longitudinal gaps, and can cause corresponding chemical changes. Wherein, the multilayer film surface structure with the modulation period of 30nm is more compact, and the microcracks and fine gaps are less, which also indicates that a proper modulation period is selected, and the amorphous MSN modulation layer is used for MoS₂The structure of the layer plays a certain role in modification, and MoS is reduced₂Crystal growth defects.

Second, the influence of the Nitrogen flow on the product morphology

Fig. 5(a1) and 5(a2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 8, in which fig. 5(a1) is a surface image and fig. 5(a2) is a cross-sectional image. As can be seen from the figure, when the nitrogen flow and the nano multilayer modulation period are in the preferred range, the surface and the section of the film can be kept to be a smooth and compact morphological structure.

Fig. 4(d1) and 4(d2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 5, in which fig. 4(d1) is a surface image and fig. 4(d2) is a cross-sectional image. As can be seen from the graph, when the modulation period is in the preferred range and the nitrogen flow rate is increased to 6sccm in the preferred range, the surface and the cross section of the thin film are more flat and dense.

Fig. 5(b1) and 5(b2) are scanning electron micrographs of the multilayer composite solid lubricating film of example 9, in which fig. 5(b1) is a surface image and fig. 5(b2) is a cross-sectional image. As can be seen from the graph, when the modulation period is within the preferred range and the nitrogen flow rate is increased to 10sccm within the preferred range, the surface and the cross section of the thin film are more flat and dense.

Fig. 5(c1) and 5(c2) are scanning electron micrographs of the multilayer composite solid lubricating film of comparative example 4, in which fig. 5(c1) is a surface image and fig. 5(c2) is a cross-sectional image. As can be seen from the graph, when the modulation period is in the preferred range and the nitrogen flow rate is increased to 20sccm in the preferred range, the surface and the cross section of the thin film are more flat and dense.

From the above analysis, pure MoS can be obtained₂The film surface completely shows typical dendritic morphology, MoS₂MSN multilayer filmThe surface appearance is mainly composed of fine particle stacks, and the structure is more compact and smooth. The cross section structure of the multilayer film is compact, and MoS is completely inhibited₂A columnar loose porous structure grows. This indicates that the high nitrogen content significantly improves the densification of the film, and the structure tends to be amorphous. In addition, the structure of the multilayer film is more compact and smooth with the increase of the nitrogen flow, and the disorder degree is more obvious. The surface of the multilayer film obtained under the condition that the nitrogen flow is 4sccm has a certain amount of defects, mainly comprising fine microcracks and cavities. When the nitrogen flow rate is more than 4sccm, defects on the surface of the multilayer film gradually decrease, and microcracks and voids are gradually annihilated. This indicates that appropriate nitrogen content and incorporation of multilayer structure (or MSN layer) into the MoS of the outermost layer of the film₂Can play a key modification role, the structural defects of the film are reduced, and the structure is more compact.

The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it is not meant that the present invention must rely on the above detailed methods for its implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.

Claims

1. A solid lubricating film, characterized in that the solid lubricating film comprises MoS₂A multi-layered structure film formed by alternately stacking layers and Mo-S-N composite layers, the MoS₂The thickness of the layer and the Mo-S-N composite layer are both nano-scale thickness, and the Mo-S-N composite layer is N-doped MoS₂And (3) a base composite layer.

2. The solid lubricating film according to claim 1, wherein the number of layers of the multilayer structure film is at least two;

preferably, the multilayer structure film has a thickness of 1 μm to 3 μm;

preferably, the MoS₂The individual layer thicknesses of the layer and the Mo-S-N composite layer are independently 6nm to 30nm, preferablySelecting the particle size to be 9nm-15 nm;

preferably, the doping amount of the N element in the Mo-S-N composite layer is 1 at.% to 10 at.%, preferably 4 at.% to 6 at.%.

3. The solid lubricating film according to any one of claims 1 or 2, wherein the solid lubricating film is supported on a substrate, preferably a steel material;

4. A method for producing a solid lubricating film according to any one of claims 1 to 3, characterised in that the method comprises the steps of:

5. The method of claim 4, further comprising forming MoS₂Preparing a Ti transition layer on the surface of the substrate before the layer and the Mo-S-N composite layer;

6. Method according to claim 4 or 5, characterized in that MoS is formed alternately on the surface of the substrate₂The method of layer and Mo-S-N composite layer comprises:

alternatively, alternately formed on the surface of the substrateMoS₂The method of layer and Mo-S-N composite layer comprises:

7. The method of claim 6, wherein the working gas is Ar.

Preferably, the nitrogen source gas is N₂Preferably N₂The purity is more than or equal to 99.999 percent;

preferably, in the step (1) and the step (2'), the ratio of the flow rates of the working gas and the nitrogen source gas is 40sccm (2sccm-10sccm), preferably 40sccm (4sccm-6 sccm);

preferably, in step (1) and step (2'), the temperature of the deposition is 150 ℃ to 250 ℃.

8. A method according to any one of claims 4 to 7, wherein the substrate is subjected to a cleaning treatment prior to use, the cleaning treatment comprising ultrasonic cleaning with acetone and alcohol in sequence, followed by drying.

9. Method according to any of claims 4-8, characterized in that the method comprises the steps of:

10. Use of a solid lubricating film according to any of claims 1 to 3, characterised in that the solid lubricating film is used for lubrication protection of steel construction materials under vacuum service conditions.