CN109694647B

CN109694647B - Long-acting solid lubricating protective coating with excellent space environment resistance

Info

Publication number: CN109694647B
Application number: CN201811597478.1A
Authority: CN
Inventors: 陈磊; 俞传永; 李红轩; 吉利; 周惠娣; 陈建敏
Original assignee: Lanzhou Zhongke Kailu Lubrication And Protection Technology Co ltd; Lanzhou Institute of Chemical Physics LICP of CAS
Current assignee: Lanzhou Zhongke Kailu Lubrication And Protection Technology Co ltd; Lanzhou Institute of Chemical Physics LICP of CAS
Priority date: 2018-12-26
Filing date: 2018-12-26
Publication date: 2021-03-02
Anticipated expiration: 2038-12-26
Also published as: CN109694647A

Abstract

The invention discloses a long-acting solid lubricating protective coating which is prepared by taking polyamide-imide resin as an adhesive, polyhedral oligomeric silsesquioxane as a modifier, polytetrafluoroethylene as a lubricant and N, N-dimethylformamide as a diluent through high-speed stirring or ball milling for uniform dispersion. On the basis of ensuring the self lubricating and protecting performance of the coating material, the PAI resin is compositely modified by POSS, so that the space environment irradiation resistance and frictional wear resistance of the lubricating coating material are greatly improved, and the service life of related equipment in a space environment can be effectively prolonged. The performance test shows that the coating prepared by the coating has good adhesion to a metal substrate, has the characteristics of good flexibility, impact resistance and the like, can still maintain the lubricating and protecting performance of the coating under the long-term irradiation of atomic oxygen, ultraviolet and ionizing radiation in a space environment (particularly a low-orbit space environment), and effectively prolongs the service life of related equipment in the space environment.

Description

Long-acting solid lubricating protective coating with excellent space environment resistance

Technical Field

The invention relates to a long-acting lubricating protective coating, in particular to a long-acting lubricating protective coating with excellent space environment resistance, which is suitable for lubricating protection of parts in a space environment and belongs to the technical field of lubricating protection.

Background

Since the middle of the last century, organic bonding solid lubricating coatings have been one of the effective approaches for solving the problem of space lubrication and protection of aerospace parts, and have been increasingly widely applied in the space field due to their low friction coefficient, long service life and wide service temperature range. However, in recent years, with frequent development of space activities, aerospace equipment is rapidly developed, and meanwhile, the use requirements of high reliability and long service life (prolonged from 3-5 years to 8-10 years) are also met, and the problems of long-acting lubrication and protection in a space environment are urgently needed to be solved for related parts. Because the existing organic bonding lubricating coating is eroded by harsh environments such as atomic oxygen, ultraviolet, ionizing radiation and the like in the space environment and gradually cannot meet the development requirement, the development of multifunctional organic bonding coatings with high performance, space protection and the like as far as possible is an urgent need for the development of the aerospace field. For the aerospace field, coatings with severe environment requirements such as atomic oxygen, electrons, high vacuum and the like have excellent space environment adaptability, and have strict requirements on mechanical properties, and development of novel long-acting lubricating protective coating materials with excellent space adaptability is crucial to meeting the use requirements of space equipment on high reliability and long service life.

Polyhedral oligomeric silsesquioxane (POSS) is a novel organic/inorganic hybrid material with a nano structure, which appears in recent years, and due to the unique nano organic/inorganic hybrid, molecular controllability and hollow cage-shaped structural characteristics, the polyhedral oligomeric silsesquioxane (POSS) can modify polymers at the molecular level, realize full hybridization of inorganic and organic components, form uniform multiphase materials, ensure that the modified polymers not only keep the excellent characteristics of processability, toughness, low cost and the like of high polymer materials, but also have the outstanding heat resistance, oxidation resistance and excellent mechanical properties of inorganic materials. And the POSS has a hollow cage structure with Si-O-Si bond as an inorganic framework and has C-C bond or C-H bond in the polymerCompared with the characteristic of easy oxidation and decomposition, Si-O, Si-C has better oxidation resistance, and particularly forms SiO on the surface after being irradiated by UV, AO and the like for a long time₂The ceramic layer effectively prevents the atomic oxygen from continuously corroding the internal material of the coating, thereby achieving the purpose of prolonging the service life of the coating. Therefore, POSS has great potential for development in the coating field in space environments.

Disclosure of Invention

The invention aims to provide a preparation method of a long-acting lubricating protective coating material with excellent space environment resistance.

Long-acting solid lubricating protective coating

The invention relates to a long-acting solid lubrication protective coating which is prepared by taking polyamide-imide resin (PAI) as an adhesive, polyhedral oligomeric silsesquioxane (POSS) as a modifier, Polytetrafluoroethylene (PTFE) as a lubricant and N, N-Dimethylformamide (DMF) as a diluent through high-speed stirring or ball milling for uniform dispersion.

The components are mixed according to the following weight percentage: 6.00-13.00% of polyamide imide (PAI), 6.00-15.00% of Polytetrafluoroethylene (PTFE), 0.30-0.80% of polyhedral oligomeric silsesquioxane (POSS) and the balance of N, N-dimethylformamide.

Wherein the polyamide-imide resin is a commercial product, and the solid content of the polyamide-imide resin is between 30 +/-3 percent. The structure of POSS has a hollow cage structure with Si-O-Si bonds as the inorganic framework, eight organic groups are attached to eight corners of the structure, R is an inert group, X is a reactive group such as amino, vinyl, epoxy, or hydroxyl, and the number of X can be 1, 2, or 8 (see fig. 1). The invention adopts POSS with different functional group types (such as amino, vinyl, epoxy and the like) and different functional group numbers (such as octaamino, monoamino, monovinyl, octavinyl and the like) and prepares different modified coatings by compounding the POSS.

The granularity of the lubricant Polytetrafluoroethylene (PTFE) is less than or equal to 10 mu m, and the purity is more than or equal to 98 percent.

The particle size of the modifier polyhedral oligomeric silsesquioxane (POSS) is less than or equal to 3 nm.

When high-speed stirring dispersion is adopted, the stirring speed is 3000-6000 rpm, and the stirring time is 5-10 min.

When ball milling dispersion is adopted, pouring polytetrafluoroethylene into a ball milling tank, adding a proper amount of N, N-dimethylformamide, and uniformly stirring to form paste; putting ceramic balls with the volume about one third of the volume of the ball milling tank, sealing the ball milling tank, putting the ball milling tank on a ball mill, and performing ball milling for more than 72 hours in a cumulative way; and then, fully mixing the polyamide-imide, the polyhedral oligomeric silsesquioxane and the ground solid component, and adding the balance of N, N-dimethylformamide.

The solid lubricating coating prepared by the invention has the solid component content of 20 +/-3%.

Second, performance test of long-acting solid lubrication protective coating

Coating of long-acting lubricating protective coating: the prepared solid lubricating coating is sprayed on the surface of the part by a spray gun under the condition of compressed air (oil-free) or compressed nitrogen. The surface of the part needs to be subjected to surface treatment such as oil removal, rust removal, sand blasting, ultrasound and the like in advance. And (3) placing the sprayed part at room temperature for 1-3 h, drying the part, and curing the part in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out for use.

The following is an analysis and explanation of various performance indexes of the long-acting solid lubrication protective coating.

1. Appearance of the coating: smooth and crackless.

2. Adhesion force: testing according to GB/T9286: and (4) level 0.

3. Flexibility: testing according to GB/T1731: 1/mm.

4. Impact resistance: testing according to GB/T1732: 50 cm.

5. The tribological performance is as follows: the friction test was performed on a CSM ball-and-disc friction wear tester. The experimental conditions are as follows: the load is 10N, the speed is 10cm/s, the radius of the steel ball is 3mm, and the amplitude is 2.5 cm. And (3) testing results: mu = 0.06-0.12, W = 1.2-4.0 x 10^-6 mm³/Nm。

6. Performance testing in a spatial environment

Irradiation experiment and structural analysis of atomic oxygen:subjecting the coating to Atomic Oxygen (AO) radiation with a total radiation dose of 2.3 × 10²¹ atom/cm². FIG. 2 is an electron topography of the coating before (a) and after (b) atomic oxygen irradiation. As can be seen from fig. 2, the smooth and dense surface becomes a honeycomb structure after AO irradiation, since organic components on the surface are degraded to generate volatile gas and escape from the surface of the coating, and POSS forms a silica protective layer on the surface of the coating through oxidation. XPS analysis of the surface of the coating (as shown in FIG. 3) shows that the element composition of the surface is obviously changed, the content of C is obviously reduced, the content of Si and O is obviously improved, and Si spectrum analysis shows that SiO generated on the surface of the coating₂And the protective layer prevents the further erosion of the atomic oxygen. FIG. 4 is a comparison of wear life before and after irradiation of the coating. It can be seen that the friction coefficient of the coating before and after irradiation is not obviously changed, which is about 0.06, and the service life of the coating after irradiation is not changed much compared with the original service life, thus showing excellent space environment resistance and tribology performance. Therefore, the coating can still maintain the lubricating and protecting performance of the coating under the long-term irradiation of atomic oxygen, ultraviolet and ionizing radiation in a space environment (particularly a low-orbit space environment), and the service life of related equipment in the space environment is effectively prolonged.

In conclusion, the coating material disclosed by the invention greatly improves the space environment irradiation resistance and the frictional wear resistance of the lubricating coating material through the POSS composite modified PAI resin on the basis of ensuring the self lubricating protection performance, and can effectively prolong the service life of related equipment in the space environment. The performance test shows that the solid lubricating coating is a high-performance bonding solid lubricating coating, the coating prepared from the solid lubricating coating has good adhesion to a metal base material, has the characteristics of good flexibility, impact resistance and the like, has a low friction coefficient and a long wear-resisting life, can effectively reduce the friction and wear between parts, has excellent space environment adaptability, and can effectively prolong the service life of the parts in a space environment.

Drawings

FIG. 1 is a three-dimensional block diagram of a POSS.

FIG. 2 is an electron topography of the coating prepared by the present invention before (a) and after (b) atomic oxygen irradiation.

FIG. 3 shows XPS survey spectra (a) and Si survey spectra (b) of the surface of a coating of the present invention before and after irradiation.

FIG. 4 is a comparison of the lifetime of the coating of the present invention before and after irradiation.

Detailed Description

In order to better understand the present invention, the following examples further illustrate the preparation method of the novel long-acting lubrication protective coating for resisting space environment.

Example 1

PAI 100g, PTFE 120g, octa-amino POSS 7g, and dimethylformamide as solvent nitrogen (balance) were weighed out separately. The raw materials are mixed and then ball-milled to be dispersed uniformly, and the dispersed lubricating coating is sprayed on the surface of a part (the surface of the part needs surface treatment such as oil removal, rust removal, sand blasting, ultrasound and the like in advance) under compressed air (oil-free) or compressed nitrogen. And (3) placing the sprayed part at room temperature for 1-3 h, drying the part, and curing the part in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out for use. The main performance indexes of the product are shown in table 1. The total irradiation dose of Atomic Oxygen (AO) is 2.3 × 10²¹ atom/cm²Experiments after irradiation show that a silicon dioxide protective layer is formed on the surface of the coating after POSS modification, and the change of the tribological properties is not great.

Example 2

PAI 90g, PTFE 110g, monoamino POSS 5.5g, and solvent nitrogen dimethyl formamide (balance) were weighed out separately. The raw materials are mixed and then ball-milled to be dispersed uniformly, and the dispersed lubricating coating is sprayed on the surface of a part (the surface of the part needs surface treatment such as oil removal, rust removal, sand blasting, ultrasound and the like in advance) under compressed air (oil-free) or compressed nitrogen. And (3) placing the sprayed part at room temperature for 1-3 h, drying the part, and curing the part in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out. The main performance indexes of the product are shown in table 1. The total irradiation dose of Atomic Oxygen (AO) is 2.3 × 10²¹atom/cm²Irradiation experiments show that a silicon dioxide protective layer is formed on the surface of the coating after POSS modification, and the change of the tribological properties is small.

Example 3

85g of PAI, 120g of PTFE, 7.5g of octavinyl POSS and the balance of dimethylformamide (nitrogen and nitrogen) as a solvent are weighed respectively. The raw materials are mixed and then ball-milled to be dispersed uniformly, and the dispersed lubricating coating is sprayed on the surface of a part (the surface of the part needs surface treatment such as oil removal, rust removal, sand blasting, ultrasound and the like in advance) under compressed air (oil-free) or compressed nitrogen. And (3) placing the sprayed part at room temperature for 1-3 h, drying the part, and curing the part in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out. The main performance indexes of the product are shown in table 1. The total irradiation dose of Atomic Oxygen (AO) is 2.3 × 10²¹ atom/cm²Irradiation experiments show that a silicon dioxide protective layer is formed on the surface of the coating after POSS modification, and the change of the tribological properties is small.

Example 4

PAI 90g, PTFE 120g, octa-epoxy POSS 7g and solvent nitrogen dimethyl formamide (the rest) are weighed respectively. The raw materials are mixed and then ball-milled to be dispersed uniformly, and the dispersed lubricating coating is sprayed on the surface of a part (the surface of the part needs surface treatment such as oil removal, rust removal, sand blasting, ultrasound and the like in advance) under compressed air (oil-free) or compressed nitrogen. And (3) placing the sprayed part at room temperature for 1-3 h, drying the part, and curing the part in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out. The main performance indexes of the product are shown in table 1. The total irradiation dose of Atomic Oxygen (AO) is 2.3 × 10²¹atom/cm²Irradiation experiments show that a silicon dioxide protective layer is formed on the surface of the coating after POSS modification, and the change of the tribological properties is small.

Example 5

110g of PAI, 95g of PTFE, 8g of monovinylPOSS and the balance of dimethylformamide (nitrogen and nitrogen) as a solvent are weighed respectively. Mixing the raw materials, ball-milling to disperse uniformly, and spraying the dispersed lubricating coating on the surface of the part (zero) under compressed air (oil-free) or compressed nitrogenSurface treatment such as oil removal, rust removal, sand blasting, ultrasonic treatment and the like is required on the surface of the workpiece in advance). And (3) placing the sprayed part at room temperature for 1-3 h, drying the part, and curing the part in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out. The main performance indexes of the product are shown in table 1. The total irradiation dose of Atomic Oxygen (AO) is 2.3 × 10²¹ atom/cm²Irradiation experiments show that a silicon dioxide protective layer is formed on the surface of the coating after POSS modification, and the change of the tribological properties is small.

Example 6

120g of PAI, 80g of PTFE, 5g of octamino POSS, 5g of monoamino POSS5g and the balance of solvent nitrogen dimethyl formamide are weighed respectively. Pouring PTFE into a ball milling tank, adding a proper amount of N, N-dimethylformamide, and uniformly stirring to form paste; putting ceramic balls with the volume about one third of the volume of the ball milling tank, sealing the ball milling tank, putting the ball milling tank on a ball mill, and performing ball milling for more than 72 hours in a cumulative way; fully mixing PAI and POSS with the ground solid components, adding the balance of N, N-dimethylformamide, and performing ball milling and uniform dispersion; the dispersed lubricating coating is sprayed on the surface of the part (the surface of the part needs surface treatment such as oil removal, rust removal, sand blasting, ultrasound and the like in advance) under compressed air (oil-free) or compressed nitrogen. And (3) placing the sprayed part at room temperature for 1-3 h, drying the part, and curing the part in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out. The main performance indexes of the product are shown in table 1. The total irradiation dose of Atomic Oxygen (AO) is 2.3 × 10²¹ atom/cm²Irradiation experiments show that a silicon dioxide protective layer is formed on the surface of the coating after POSS modification, and the change of the tribological properties is small.

Example 7

PAI 100g, PTFE 120g, octa-amino POSS 7g, and dimethylformamide as solvent nitrogen (balance) were weighed out separately. The raw materials are mixed and uniformly dispersed by high-speed stirring (the stirring speed is 3000-6000 rpm, and the stirring time is 5-10 min), and the dispersed lubricating coating is sprayed on the surface of a part (the surface of the part needs surface treatment such as oil removal, rust removal, sand blasting, ultrasound and the like in advance) under compressed air (oil-free) or compressed nitrogen. Spraying of paintAnd (3) placing the good parts at room temperature for 1-3 h, surface drying, and curing in a blast oven. Curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 plus or minus 5 ℃ for 1 hour, and taking out. The main performance indexes of the product are shown in table 1. The total irradiation dose of Atomic Oxygen (AO) is 2.3 × 10²¹ atom/cm²Irradiation experiments show that a silicon dioxide protective layer is formed on the surface of the coating after POSS modification, and the change of the tribological properties is small.

Claims

1. A preparation method of a long-acting solid lubricating protective coating with excellent space environment resistance is characterized by comprising the following steps: respectively weighing 110g of PAI, 95g of PTFE, 8g of monovinyl POSS and the balance of solvent nitrogen dimethyl formamide; mixing the raw materials, ball-milling and dispersing uniformly, and spraying the dispersed lubricating coating on the surface of the part under the condition of oil-free compressed air or compressed nitrogen; placing the sprayed part at room temperature for 1-3 h, drying the part on the surface, and curing the part in a blast oven; curing conditions are as follows: keeping the temperature at 150 +/-5 ℃ for 1 h; keeping the temperature at 280 +/-5 ℃ for 1 hour, and taking out;

the surface of the part needs to be subjected to oil removal, rust removal, sand blasting and ultrasonic treatment in advance;

the polyamide-imide resin is a commercial product, and the solid content of the polyamide-imide resin is 30 +/-3 percent; the granularity of the lubricant polytetrafluoroethylene is less than or equal to 10 mu m, and the purity of the lubricant polytetrafluoroethylene is more than or equal to 98 percent; the particle size of the modifier polyhedral oligomeric silsesquioxane is less than or equal to 3 nm; the solid component content of the solid lubricating coating is 20 +/-3%;

the tribological properties of the prepared solid lubricating protective coating are as follows: μ =0.079, W =1.2 × 10^-6 mm³/Nm。