阅读说明：本技术 一种在工程基材上获得二维复合超润滑表面的方法 (Method for obtaining two-dimensional composite super-lubricating surface on engineering base material ) 是由 吉利 李红轩 李畔畔 刘晓红 周惠娣 陈建敏 于 2020-06-15 设计创作，主要内容包括：本发明提供了一种在工程基材上获得二维复合超润滑表面的方法,先通过常规的激光织构方法在基材表面构筑微米尺度的凹凸体；再将离子型二维纳米材料复配物经高速搅拌、超声分散于无水乙醇中,得二维润滑剂复配分散液；并其喷涂到上述经预处理的基材表面,空气中表干,即获得二维复合超润滑表面。本发明对工程基材表面设计制备微米尺度凹凸体,实现将宏观接触面分解为微纳接触点的作用；然后通过二维材料摩擦自定序、共价/离子以及离子/离子异质复配等特殊设计来控制每个接触点位置界面间定序状态、化学相互作用、非公度性,从而满足“超润滑”理论原理的三个基本条件,在工程粗糙的钢-钢宏观接触摩擦副上,实现了长效稳定的超润滑性能。(The invention provides a method for obtaining a two-dimensional composite super-lubricating surface on an engineering substrate, which comprises the steps of constructing a concave-convex body with a micrometer scale on the surface of the substrate by a conventional laser texture method; then, the ionic two-dimensional nano material compound is subjected to high-speed stirring and ultrasonic dispersion in absolute ethyl alcohol to obtain a two-dimensional lubricant compound dispersion liquid; and spraying the mixture on the surface of the pretreated base material, and surface drying in the air to obtain the two-dimensional composite super-lubricating surface. The invention designs and prepares a micron-scale concave-convex body on the surface of an engineering substrate, and realizes the function of decomposing a macroscopic contact surface into micro-nano contact points; then the sequencing state, the chemical interaction and the non-axiality of the interface of each contact point position are controlled by special designs such as two-dimensional material friction self-sequencing, covalent/ion and ion/ion heterogeneous combination, thereby meeting three basic conditions of the theoretical principle of 'super lubrication', and realizing long-acting stable super-lubrication performance on a steel-steel macroscopic contact friction pair with rough engineering.)

1. a method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate, comprising the steps of:

(1) pretreatment of the surface of the substrate: constructing a concave-convex body with a micron scale on the surface of a base material by sanding, sand blasting or a conventional laser texture method;

(2) preparing a two-dimensional lubricant compound dispersion liquid: the ionic two-dimensional nano material compound is stirred at a high speed and dispersed in absolute ethyl alcohol by ultrasonic to obtain a two-dimensional lubricant compound dispersion liquid;

(3) preparing a lubricating coating on the surface of a base material: and spraying the two-dimensional lubricant compound dispersion liquid on the surface of the pretreated base material under the compressed air or compressed nitrogen, and drying the surface in the air, namely obtaining the two-dimensional composite super-lubricating surface on the engineering base material.

2. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: in the step (1), the base material is metal base material steel, titanium alloy or aluminum.

3. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: in the step (1), the base material is ceramic material alumina, silicon oxide, silicon nitride.

4. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: the surface roughness control range of the pretreated substrate in the step (1) is 0.1-5 microns; the ratio of the bump contact area on the surface of the substrate is 1/50 or less.

5. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: in the step (2), the ionic two-dimensional nano material compound is a compound of two different types of ionic two-dimensional nano materials, and the ionic two-dimensional nano material is selected from MoS₂、WS₂、TaS₂、WSe₂、TaSe₂、NbS₂、NbSe₂And the two ionic two-dimensional nano materials are compounded according to the mass ratio of 1: 0.1-1: 10.

6. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: in the step (2), the ionic two-dimensional nano material compound is a compound of an ionic two-dimensional nano material and a covalent two-dimensional nano material, and the ionic two-dimensional nano material is MoS _2、WS₂、TaS₂、WSe₂、TaSe₂、NbS₂、NbSe₂And the covalent type two-dimensional nano material is any one of graphene, h-BN, mica and black phosphorus, and the ionic type two-dimensional nano material and the covalent type two-dimensional nano material are compounded according to the mass ratio of 1: 0.2-1: 5.

7. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: in the step (2), the number of layers of the ionic two-dimensional nano material and the covalent two-dimensional nano material is less than 50.

8. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: and (3) adding resin glue which is 0.5-5 times of the mass of the ionic two-dimensional nano material compound into the two-dimensional lubricant compound dispersion liquid in the step (2).

9. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: the high-speed stirring speed is 3000-6000 rpm, and the stirring time is 10-60 min; the ultrasonic power of ultrasonic dispersion is 500-1500W, and the ultrasonic time is 0.5-3 h.

10. The method of obtaining a two-dimensional composite super-lubricated surface on an engineered substrate according to claim 1, wherein: the thickness of the coating sprayed on the surface of the base material is 1-30 microns.

Technical Field

The invention relates to a preparation method of a composite super-lubricating surface, in particular to a method for obtaining a two-dimensional composite super-lubricating surface on an engineering substrate, and belongs to the field of lubrication and friction.

Background

The friction and wear is a ubiquitous phenomenon of a moving machine, and statistics shows that primary energy of 1/3 in the world is consumed by friction, 4/5 of mechanical parts fails due to wear, and the friction and wear loss accounts for 5% -7% of GDP in industrialized countries. Meanwhile, in the high-technology field, the friction and wear problem is the main reason for causing equipment failure and restricting the reliability of the equipment. NASA research reports indicate that: a significant proportion of spatial mechanical component failures are associated with frictional wear problems. Lubrication is the most important technical approach to solve the problems of friction energy consumption and material abrasion.

The super-lubrication is a new concept technology which is provided in recent years and can greatly break through the limit of the lubricating property of the existing material, the theory is zero, and the friction coefficient can be as low as below 0.01, namely 10 in engineering practice^-3The magnitude is 1 to 2 magnitude orders lower than the friction coefficient of about 0.1 of the conventional solid lubricating material. Therefore, the development of the super-lubrication technology not only has profound significance for saving energy, reducing consumption and promoting national economy development, But will also revolutionize the design and operational reliability of high technology equipment.

In 1991, Hirano and Shinjo, Japanese scholars, proposed the basic concept and principle of "super-lubrication": when the two surfaces are mutually metric (namely the ratio of lattice constants is rational number and the orientations are consistent), atoms can slide only by overcoming the slip potential barrier at the same time, and the resistance to be overcome by the system slip is the superposition of the slip resistance of each atom, so that the system slip resistance is huge; the system static friction of an infinite non-metric lattice surface tends to zero and there is no energy dissipation during sliding, which means that the kinetic friction is also zero. However, according to this theoretical principle, it is currently only experimentally possible to obtain a state of superlubrication at ideal single-crystal contact conditions on the micrometer scale. In the macroscopic friction process, the applied load is large (several N orders of magnitude), the contact sliding occurs on a large-area and uneven macroscopic surface, the friction performance influence factors are numerous, the influence of the microstructure (including microscopic lattice defects, lattice deformation, gas adsorption, functional groups and the like) and the influence of various structural factors such as macroscopic polycrystalline orientation, edge bonds, roughness, macroscopic force destructive effect and the like are realized, and an ideal non-metric, deformation-free and pollution-free super-lubrication state is difficult to form on a macroscopic engineering base material in large-area contact. Two-dimensional materials such as graphene and the like show some special phenomena and effects in the macroscopic friction process, and the realization of super lubrication is facilitated. The american Argonne national laboratory researchers reported in 2015 in the journal of Science that graphene and nano-diamond particles compounded with diamond-like carbon film formulation could achieve super-lubricity (coefficient of friction as low as 0.004) under macroscopic contact conditions. The graphene is wound on the diamond particles, surface contact is changed into point contact, non-degree contact is kept favorably, and structural deformation and interface chemical action are reduced. The method has the disadvantages that the formation of the graphene-wound diamond composite structure depends on certain test conditions, the material system is complicated, the service life of the obtained super-lubrication state is short, and the engineered preparation is difficult to realize. Therefore, the method for realizing macroscopic super-lubricity on the engineering base material by utilizing the structural characteristics of the two-dimensional material is a breakthrough and is expected to develop a novel engineered super-lubricity concept technology.

Disclosure of Invention

The invention aims to provide a method for obtaining a two-dimensional composite super-lubricating surface on an engineering substrate.

Preparation of one-dimensional and two-dimensional composite super-lubricating surface

The invention discloses a method for obtaining a two-dimensional composite super-lubricating surface on an engineering substrate, which comprises the following steps:

(1) pretreatment of the surface of the substrate: the substrate surface is constructed with micro-scale asperities by sanding, sandblasting or conventional laser texturing. The base material can be selected from metals such as steel, titanium alloy, aluminum and the like, and can also be selected from ceramics such as alumina, silicon oxide, silicon nitride and the like. The surface roughness control range of the pretreated base material is 0.1-5 microns; the ratio of the bump contact area on the surface of the substrate is 1/50 or less.

(2) Preparing a two-dimensional lubricant compound dispersion liquid: and (3) dispersing the ionic two-dimensional nano material compound in absolute ethyl alcohol through high-speed stirring and ultrasonic dispersion to obtain a two-dimensional lubricant compound dispersion liquid. Wherein the ionic two-dimensional nanomaterial compound is a compound of two different types of ionic two-dimensional nanomaterials; wherein the ionic two-dimensional nanomaterial is selected from MoS₂、WS₂、TaS₂、WSe₂、TaSe₂、NbS₂、NbSe₂And any two of the alpha-ZrP and the two ionic two-dimensional nano materials are compounded according to the mass ratio of 1: 0.1-1: 10. The ionic two-dimensional nanomaterial complex is a complex of an ionic two-dimensional nanomaterial and a covalent two-dimensional nanomaterial, and the ionic two-dimensional nanomaterial and the covalent two-dimensional nanomaterial are compounded in a mass ratio of 1: 0.2-1: 5. Wherein the ionic two-dimensional nano material is MoS _2、WS₂、TaS₂、WSe₂、TaSe₂、NbS₂、NbSe₂Any one of alpha-ZrP; the covalent two-dimensional nano material is any one of graphene, h-BN, mica and black phosphorus. Whether the two-dimensional nanomaterial is an ionic two-dimensional nanomaterial or a covalent two-dimensional nanomaterial, the number of layers of the two-dimensional nanomaterial is less than 50.

In order to enhance the binding force and the bearing capacity of the dispersion liquid and the base material, resin glue is added into the spraying dispersion liquid. Such as polyamideimide resins, epoxy resins. The addition amount of the resin adhesive is 0.5-5 times of the mass of the ionic two-dimensional nano material compound.

The high-speed stirring speed is 3000-6000 rpm, and the stirring time is 10-60 min; the ultrasonic power of ultrasonic dispersion is 500-1500W, and the ultrasonic time is 0.5-3 h.

(3) Preparing a lubricating coating on the surface of a base material: and spraying the two-dimensional lubricant compound dispersion liquid on the surface of the pretreated base material under the condition of compressed air (oil-free) or compressed nitrogen, and drying the surface in the air, namely obtaining the two-dimensional composite super-lubricating surface on the engineering base material. The thickness of the coating sprayed on the surface of the base material is 1-30 microns.

Structural characterization of two-dimensional and two-dimensional composite super-lubricating surface

Fig. 1 is a typical morphology of the substrate surface after laser texturing, and it can be seen that the substrate surface after laser texturing has a relatively significant roughness and is uniformly distributed with micro-scale asperities.

FIG. 2 is a high-resolution transmission electron microscope image of the lubricating coating on the surface of the substrate prepared by the invention. Through the analysis of a high-resolution transmission electron microscope of a coating heterogeneous sliding interface, an ion/covalent layer-layer heterogeneous sliding composite interface structure is formed in the sliding process, and meanwhile, molar stripes matched with interface lattices are observed, which indicates that a very good non-metric contact state exists at a heterogeneous contact interface. On one hand, the special structure reduces the chemical interaction between adjacent layers through the design of ion/covalent configuration; on the other hand, the method improves the atom interlocking caused by the matching of the lattice degree between layers, reduces the resistance of the interlayer slippage and greatly reduces the friction coefficient.

Lubricating property of three-dimensional and two-dimensional composite super-lubricating surface

Evaluation was carried out on a ball-and-disk friction tester: the planar sample prepared by the method of the present invention was used as a lower sample, and a commercial steel ball (Φ 6 mm, AISI52100,Ra 20 nm) is the upper sample, the reciprocating linear motion is carried out, the reciprocating stroke is 5mm, the motion frequency is 6.3Hz, and the maximum Hertz contact stress is 0.5 MPa.

FIG. 3 shows the test results of the super-lubricity of the surface prepared according to the present invention. The results of fig. 3 show that the tested coefficient of friction stabilizes at 0.01 in atmospheric conditions; the friction coefficient is stable at 0.007 under the nitrogen environment test, and the super-slip state can be maintained at 2 x 10 ⁵More than one cycle.

Under the same test condition, the friction coefficient of the hydrogen-containing carbon film material which is acknowledged to have the super-slip characteristic is about 0.015, and the accuracy of the extremely low friction coefficient obtained by the method is verified.

In conclusion, the invention provides a new principle of obtaining a macro scale super-lubricating state by the combined expansion of a micro/nano scale non-metric contact super-lubricating state, and on one hand, a micro-nano concave-convex body is designed and prepared on the surface of an engineering base material, so that the effect of decomposing a macro contact surface into micro-nano contact points is realized; on the other hand, the sequencing state, the chemical interaction and the non-axiality of the interface of each contact point position are controlled through special designs such as two-dimensional material friction self-sequencing, covalent/ion and ion/ion heterogeneous combination, so that three basic conditions meeting the theoretical principle of super lubrication can be realized by relying on fixed protruding points on a substrate, the material system is simple, the obtained macro super lubrication performance is more stable and durable, the long-acting stable super lubrication performance is realized, and the method is suitable for popularization and application under the engineering parts and the operation conditions.

Drawings

FIG. 1 shows a typical topography of a substrate surface after laser texturing.

FIG. 2 is a high-resolution transmission electron microscope image of a two-dimensional composite super-lubricated surface prepared by the invention.

FIG. 3 shows the super-lubricity test results of the two-dimensional composite super-lubricated surface prepared by the invention.

Detailed Description

The method of the present invention for obtaining a two-dimensional composite super-lubricious surface on an engineered substrate is further illustrated by the following specific examples.