CN111662617A

CN111662617A - Aluminum alloy surface coating with autonomous and non-autonomous repair functions

Info

Publication number: CN111662617A
Application number: CN202010727111.8A
Authority: CN
Inventors: 王运雷; 姜中涛; 曹川川; 张�杰; 董井忍
Original assignee: Chongqing University of Arts and Sciences
Current assignee: Chongqing University of Arts and Sciences
Priority date: 2020-07-26
Filing date: 2020-07-26
Publication date: 2020-09-15

Abstract

The invention discloses an aluminum alloy surface coating with autonomous and non-autonomous repairing functions, which comprises epoxy resin shape memory film forming materials, carbon fibers, 3-aminopropyltrimethoxysilane, tetraethoxysilane, bisphenol A, aniline, paraformaldehyde, microcapsules, graphene oxide, polyaniline, muscovite, nanoscale porous silica and a coupling agent, wherein the microcapsules are of a three-layer coating structure, the inner layer of the microcapsules is polyurea formaldehyde coated glycidyl methacrylate, a coating intermediate layer is formed by depositing a layer of mixture of isophorone diisocyanate, azo polyester and polyisobutylene on the inner layer, and a paraffin coating outer layer is formed by depositing a layer of mixture of isophorone diisocyanate, azo polyester and polyisobutylene on the intermediate layer through a solvent volatilization method; the long-acting protection capability of the coating is complementarily improved in multiple aspects by combining an autonomous repair mechanism and a non-autonomous repair mechanism, so that long-acting protection on the aluminum alloy matrix is realized. The coating material of the invention not only can repair the corrosion resistance and shielding performance of the coating, but also can carry out functional multiple repair on the mechanical strength, adhesion performance and surface property of the coating.

Description

Aluminum alloy surface coating with autonomous and non-autonomous repair functions

Technical Field

The invention relates to a coating material, in particular to an aluminum alloy surface coating with multiple repair functions and self-repair and non-self-repair functions.

Background

Corrosion of the metal is the process of generating new phases on the surface of the metal. When a pure metal or an alloy is subjected to the action of some chemical or electrochemical corrosion medium in a certain environment, a stable compound layer is newly formed on the surface of the metal, the state of the metal is changed, the new phase is defined as a corrosion product, and the process is a corrosion phenomenon on the surface of the metal. The study found that Cl-containing compounds exist in the environment^-Corrosive particles such as substances, nitrates or sulfates, etc., generally cause the corrosion behavior of metals, and the corrosion process of metals is essentially spontaneous. Corrosion can significantly affect the physicochemical properties of the metal and destroy the geometric structure of the metal material, seriously affecting the service life of the metal. Corrosion prevention of metal coatings is one of the most effective methods for preventing corrosion of metals, and corrosion-resistant coatings are affected by environmental factors during use, and defects are generated inside the coatings, such as volatilization of organic solvents during curing, stress generation during reaction of high molecular polymers, improper surface pretreatment processes, and the like. These surface microscopic defects can allow for the penetration of corrosive media into the channels, and the penetrated media gradually cause the failure of the coating, affect the service life of the coating, accelerate the peeling of the metal surface coating, and further accelerate the corrosion of the metal. The main repair mechanisms of the self-repairing coating can be divided into an autonomous type and a non-autonomous type. The autonomous type is divided into a film forming substance type and a corrosion inhibitor type. The non-autonomous type is classified into temperature response, light response stimulus, and the like. Most of the existing self-repairing coatings realize the repair of the coating defects based on a single repair mechanism. The main limitation of the autonomous repair mechanism is that it is difficult to provide a coating to the metal substrate when the film-forming material and the corrosion inhibitor are exhaustedLong-acting protection. The non-autonomous repair mechanism can repair the defects and the shielding effect of the coating under common external stimulation by depending on the physical or chemical properties of the coating.

Disclosure of Invention

In view of the above, the present invention provides an aluminum alloy surface coating with multiple repair functions and with autonomous and non-autonomous repair functions, which combines autonomous and non-autonomous dual repair mechanisms to achieve long-term protection of an aluminum alloy substrate.

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function comprises the following raw materials in parts by weight: 50-100 parts of epoxy resin shape memory film forming matter, 10-20 parts of carbon fiber, 5-15 parts of 3-aminopropyltrimethoxysilane, 5-15 parts of ethyl orthosilicate, 25-35 parts of bisphenol A, 10-15 parts of aniline, 15-20 parts of paraformaldehyde, 40-50 parts of microcapsule, 5-10 parts of graphene oxide, 5-10 parts of polyaniline, 5-10 parts of muscovite, 1-3 parts of nano-porous silicon dioxide and 2-6 parts of coupling agent, wherein the microcapsule is of a three-layer coating structure, the inner layer is polyurea formaldehyde coated glycidyl methacrylate, a layer of mixture of isophorone diisocyanate, azo polyester and polyisobutylene (photoinitiator) is deposited on the inner layer to form a coated middle layer, and a layer of paraffin coated outer layer is deposited on the middle layer by a solvent volatilization method;

further, the raw materials comprise the following components in parts by weight: 75 parts of epoxy resin shape memory film forming matter, 15 parts of carbon fiber, 10 parts of 3-aminopropyl trimethoxy silane, 10 parts of ethyl orthosilicate, 30 parts of bisphenol A, 13 parts of aniline, 17 parts of paraformaldehyde, 45 parts of microcapsule, 7 parts of graphene oxide, 7 parts of polyaniline, 7 parts of muscovite, 2 parts of nano-porous silica and 4 parts of coupling agent;

further, the coupling agent is a mixture of vinyltriethoxysilane and titanate;

further, the mass ratio of the vinyltriethoxysilane to the teracid ester in the coupling agent is 2: 1;

further, the nano-scale porous silicon dioxide is loaded with a composite corrosion inhibitor by a low-pressure infiltration method;

further, the compound corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole;

further, the loading amount of the composite corrosion inhibitor is 60-70 wt% of the silicon dioxide;

further, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole in the composite corrosion inhibitor is 3: 2: 1.

the invention has the beneficial effects that: the aluminum alloy surface coating material with the autonomous and non-autonomous repairing functions disclosed by the invention has the advantages that the long-acting protection capability of the coating is complementarily improved in multiple aspects by combining autonomous and non-autonomous repairing mechanisms, and the long-acting protection on an aluminum alloy matrix is realized. The coating material of the invention not only can repair the corrosion resistance and shielding performance of the coating, but also can carry out functional multiple repair on the mechanical strength, adhesion performance and surface property of the coating.

Detailed Description

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function of the embodiment comprises the following raw materials in parts by weight: 50-100 parts of epoxy resin shape memory film forming matter, 10-20 parts of carbon fiber, 5-15 parts of 3-aminopropyltrimethoxysilane, 5-15 parts of ethyl orthosilicate, 25-35 parts of bisphenol A, 10-15 parts of aniline, 15-20 parts of paraformaldehyde, 40-50 parts of microcapsule, 5-10 parts of graphene oxide, 5-10 parts of polyaniline, 5-10 parts of muscovite, 1-3 parts of nano-porous silicon dioxide and 2-6 parts of coupling agent, wherein the microcapsule is of a three-layer coating structure, the inner layer is polyurea formaldehyde coated glycidyl methacrylate, a layer of mixture of isophorone diisocyanate, azo polyester and polyisobutylene (photoinitiator) is deposited on the inner layer to form a coated middle layer, and a layer of paraffin coated outer layer is deposited on the middle layer by a solvent volatilization method; the epoxy resin shape memory film forming material is prepared by curing epoxy resin and epoxy resin by using the conventional method, the epoxy resin is toughened by carbon fiber, polyaniline, muscovite and nano-scale porous silicon dioxide are combined to improve the corrosion resistance of the coating, and aniline is inserted between muscovite layers and is subjected to oxidative polymerization between the muscovite layers, so that the coating has high corrosion resistance and good thermal stability; the amino in the 3-aminopropyl trimethoxy silane and epoxy resin are subjected to ring-opening crosslinking reaction, and the hardness, heat resistance and water increasing property of the coating are further improved by utilizing the synergistic cooperation effect of the 3-aminopropyl trimethoxy silane and ethyl orthosilicate; graphene oxide and polyaniline act together, and polyaniline is added into the coating after wrapping the graphene oxide by adopting an in-situ polymerization method, so that the coating can be uniformly dispersed, corrosive media are effectively slowed down or even prevented from permeating into the coating, and the corrosion resistance of the coating is improved; bisphenol A, aniline and paraformaldehyde are subjected to ring-opening polymerization to form a cross-linked network, so that the coating is endowed with the capability of blocking a corrosion medium, a good shielding effect is provided, the adhesion between the coating and an aluminum alloy surface is ensured, and the coating is not easy to peel off in the corrosion protection process due to good adhesion. The microcapsule adopts a multilayer structure, does not need a catalyst, adopts the microcapsule taking the self-repairing reagent as a core material, and achieves the self-repairing purpose after the microcapsule is broken and released from the microcapsule. Isophorone diisocyanate is a compound with two-NcO groups in a molecular formula, and can react with isophorone diisocyanate in the presence of water molecules or amine substances to finally generate a high molecular polymer; the long-wave ultraviolet rays absorbed by the polyisobutylene enable the azo polyester to be converted from a solid state to a liquid state, so that damaged sites in the azo polyester can be self-repaired under illumination, and the heat generated by illumination can trigger the shape memory effect of the coating to enable the shape of the damaged area of the coating to be restored to the original state.

The coating material provided by the invention utilizes the auxiliary effects of the epoxy resin shape memory film-forming material and the microcapsule as well as other auxiliary agents, the super-hydrophobic capacity and the shielding property of the coating are well repaired, and the coating can spontaneously complete the shape memory self-repairing process of the damaged coating by utilizing heat generated by short-time irradiation of sunlight in an outdoor insolation environment.

In the embodiment, the raw materials comprise the following components in parts by weight: 75 parts of epoxy resin shape memory film forming matter, 15 parts of carbon fiber, 10 parts of 3-aminopropyl trimethoxy silane, 10 parts of ethyl orthosilicate, 30 parts of bisphenol A, 13 parts of aniline, 17 parts of paraformaldehyde, 45 parts of microcapsule, 7 parts of graphene oxide, 7 parts of polyaniline, 7 parts of muscovite, 2 parts of nano-porous silica and 4 parts of coupling agent; is a preferred embodiment.

In this embodiment, the coupling agent is a mixture of vinyltriethoxysilane and titanate; the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1; through the combination of the acting force between titanate molecules and the coating and the combination of the vinyltriethoxysilane and the chemical bond of the coating, the adhesive force and the cohesive force of the coating are improved.

In this embodiment, the nano-scale porous silica is loaded with a composite corrosion inhibitor by a low pressure infiltration method; the nano-scale porous silicon dioxide is used as a sealant by being matched with polyaniline, muscovite and epoxy resin, and a composite corrosion inhibitor is loaded by utilizing the porous structure of the nano-scale porous silicon dioxide. The microcapsule and the nano-scale porous silicon dioxide loaded with the composite corrosion inhibitor act together, so that the coating can repair the damage inside and outside the coating, the service life of the coating is prolonged, the long-acting protection on the aluminum alloy matrix is realized, and the low anticorrosion capability and even the loss of the anticorrosion capability caused by the complete release of the slow-release agent are avoided.

In the embodiment, the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole; the loading amount of the composite corrosion inhibitor is 60-70% of the weight percentage of the silicon dioxide; in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1.

example one

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function of the embodiment comprises the following raw materials in parts by weight: 50 parts of epoxy resin shape memory film forming matter, 10 parts of carbon fiber, 5 parts of 3-aminopropyl trimethoxy silane, 5 parts of ethyl orthosilicate, 25 parts of bisphenol A, 10 parts of aniline, 15 parts of paraformaldehyde, 40 parts of microcapsule, 5 parts of graphene oxide, 5 parts of polyaniline, 5 parts of muscovite, 1 part of nano-porous silica and 2 parts of coupling agent.

In this embodiment, the coupling agent is a mixture of vinyltriethoxysilane and titanate; the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1; the nano-scale porous silicon dioxide is loaded with a composite corrosion inhibitor by a low-pressure permeation method; the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole; the loading amount of the composite corrosion inhibitor is 60 weight percent of the silicon dioxide; in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1.

example two

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function of the embodiment comprises the following raw materials in parts by weight: 100 parts of epoxy resin shape memory film forming matter, 20 parts of carbon fiber, 15 parts of 3-aminopropyl trimethoxy silane, 15 parts of ethyl orthosilicate, 35 parts of bisphenol A, 15 parts of aniline, 20 parts of paraformaldehyde, 50 parts of microcapsule, 10 parts of graphene oxide, 10 parts of polyaniline, 10 parts of muscovite, 3 parts of nano-porous silicon dioxide and 6 parts of coupling agent.

In this embodiment, the coupling agent is a mixture of vinyltriethoxysilane and titanate; the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1; the nano-scale porous silicon dioxide is loaded with a composite corrosion inhibitor by a low-pressure permeation method; the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole; the loading amount of the composite corrosion inhibitor is 70 weight percent of the silicon dioxide; in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1.

EXAMPLE III

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function of the embodiment comprises the following raw materials in parts by weight: 50 parts of epoxy resin shape memory film forming matter, 20 parts of carbon fiber, 5 parts of 3-aminopropyl trimethoxy silane, 15 parts of ethyl orthosilicate, 25 parts of bisphenol A, 15 parts of aniline, 15 parts of paraformaldehyde, 50 parts of microcapsule, 5 parts of graphene oxide, 10 parts of polyaniline, 5 parts of muscovite, 3 parts of nano-porous silicon dioxide and 2 parts of coupling agent.

In this embodiment, the coupling agent is a mixture of vinyltriethoxysilane and titanate; the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1; the nano-scale porous silicon dioxide is loaded with a composite corrosion inhibitor by a low-pressure permeation method; the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole; the loading amount of the composite corrosion inhibitor is 65 weight percent of the silicon dioxide; in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1.

example four

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function of the embodiment comprises the following raw materials in parts by weight: 100 parts of epoxy resin shape memory film forming matter, 10 parts of carbon fiber, 15 parts of 3-aminopropyl trimethoxy silane, 5 parts of ethyl orthosilicate, 35 parts of bisphenol A, 10 parts of aniline, 20 parts of paraformaldehyde, 40 parts of microcapsule, 10 parts of graphene oxide, 5 parts of polyaniline, 10 parts of muscovite, 1 part of nano-porous silica and 6 parts of coupling agent.

In this embodiment, the coupling agent is a mixture of vinyltriethoxysilane and titanate; the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1; the nano-scale porous silicon dioxide is loaded with a composite corrosion inhibitor by a low-pressure permeation method; the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole; the loading amount of the composite corrosion inhibitor is 68 weight percent of the silicon dioxide; in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1.

EXAMPLE five

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function of the embodiment comprises the following raw materials in parts by weight: 80 parts of epoxy resin shape memory film forming matter, 11 parts of carbon fiber, 13 parts of 3-aminopropyl trimethoxy silane, 10 parts of ethyl orthosilicate, 32 parts of bisphenol A, 13 parts of aniline, 20 parts of paraformaldehyde, 45 parts of microcapsule, 6 parts of graphene oxide, 10 parts of polyaniline, 7 parts of muscovite, 1 part of nano-porous silica and 5 parts of coupling agent.

In this embodiment, the coupling agent is a mixture of vinyltriethoxysilane and titanate; the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1; the nano-scale porous silicon dioxide is loaded with a composite corrosion inhibitor by a low-pressure permeation method; the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole; the loading amount of the composite corrosion inhibitor is 62 weight percent of the silicon dioxide; in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1.

EXAMPLE six

The aluminum alloy surface coating with the self-repairing function and the non-self-repairing function of the embodiment comprises the following raw materials in parts by weight: 75 parts of epoxy resin shape memory film forming matter, 15 parts of carbon fiber, 10 parts of 3-aminopropyl trimethoxy silane, 10 parts of ethyl orthosilicate, 30 parts of bisphenol A, 13 parts of aniline, 17 parts of paraformaldehyde, 45 parts of microcapsule, 7 parts of graphene oxide, 7 parts of polyaniline, 7 parts of muscovite, 2 parts of nano-porous silica and 4 parts of coupling agent.

In this embodiment, the coupling agent is a mixture of vinyltriethoxysilane and titanate; the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1; the nano-scale porous silicon dioxide is loaded with a composite corrosion inhibitor by a low-pressure permeation method; the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole; the loading amount of the composite corrosion inhibitor is 65 weight percent of the silicon dioxide; in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1. using the coating materials of the above examples, the aluminum alloy sheet was treated using a prior art method, and the coating of example one was used for testing:

1. the aluminum alloy sheet was folded in half and bent at 70 degrees, the bent portion was peeled off 5 times with an adhesive tape, and the degree of peeling was examined under an X20 magnifying glass, resulting in no cracks.

2. The aluminum alloy sheet was immersed in boiling water for 2 hours, left to stand at room temperature for 24 hours, bent at 70 degrees, and the bent portion was peeled off 5 times with an adhesive tape, and the degree of peeling was examined under an X20 magnifying glass, resulting in no cracks.

3. The aluminum alloy sheet was cut open and sprayed with 5% sodium chloride solution for 400 hours without bubbling.

4. The samples were placed in NaCl solution (3.5 wt.%, static, 18 days), NaCl solution (3.5)

wt.%, dynamic, 50 hours) and neutral salt spray (48 hours) environments. And observing and analyzing the wettability, the micro-morphology and the surface chemical composition of the sample surface after the experiment is finished. The results show that the wettability, the micro-morphology and the chemical composition of the surface do not change much after the sample is soaked in a static NaCl solution (3.5 wt.%) for 18 days. In a flowing NaCl (3.5 wt.%) solution, the surface wettability change of the sample was accelerated; and with the increase of the flow velocity, the decrease of the contact angle, the change of the surface appearance and the increase of the surface oxygen content caused by corrosion are greatly accelerated. The original contact angle of the surface of the aluminum alloy is 169.0 +/-2.0 degrees, the rolling angle is 3.8 +/-0.7 degrees, when the flow velocity is 0.5m/s, after 50 hours, the contact angle is reduced to 167.2 +/-1.5 degrees; 1.0m/s, down to 165.2 +/-1.4 degrees; 2m/s, down to 161.3 + -1.9 deg. After being exposed in a neutral salt spray environment for 48 hours, the contact angle of the prepared super-hydrophobic sample is reduced to 164.9 +/-2.0 degrees; after the sample is stored in a neutral salt spray environment for 48 hours, the wettability, the micro-morphology and the change of chemical composition of the surface of the sample are observed, and the result shows that the sample can well resist the invasion of corrosive media in the environment where the sample is located, and the surface has good corrosion resistance and stability.

Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.

Claims

1. An aluminum alloy surface coating having autonomous and non-autonomous repair functions, characterized by: the raw materials comprise the following components in parts by weight: 50-100 parts of epoxy resin shape memory film forming matter, 10-20 parts of carbon fiber, 5-15 parts of 3-aminopropyltrimethoxysilane, 5-15 parts of ethyl orthosilicate, 25-35 parts of bisphenol A, 10-15 parts of aniline, 15-20 parts of paraformaldehyde, 40-50 parts of microcapsules, 5-10 parts of graphene oxide, 5-10 parts of polyaniline, 5-10 parts of muscovite, 1-3 parts of nano porous silica and 2-6 parts of coupling agent, wherein the microcapsules are of a three-layer coating structure, the inner layer of the microcapsules is methacrylic glycidyl ether coated by polyurea formaldehyde, a coating intermediate layer is formed by depositing a layer of isophorone diisocyanate, azo polyester and polyisobutylene mixture on the inner layer, and a paraffin coating outer layer is formed on the intermediate layer by a solvent volatilization method.

2. An aluminum alloy surface coating with autonomous and non-autonomous repair capabilities according to claim 1, characterized in that: the raw materials comprise the following components in parts by weight: 75 parts of epoxy resin shape memory film forming matter, 15 parts of carbon fiber, 10 parts of 3-aminopropyl trimethoxy silane, 10 parts of ethyl orthosilicate, 30 parts of bisphenol A, 13 parts of aniline, 17 parts of paraformaldehyde, 45 parts of microcapsule, 7 parts of graphene oxide, 7 parts of polyaniline, 7 parts of muscovite, 2 parts of nano-porous silica and 4 parts of coupling agent.

3. An aluminum alloy surface coating with autonomous and non-autonomous repair capabilities according to claim 1, characterized in that: the coupling agent is a mixture of vinyl triethoxysilane and titanate.

4. An aluminum alloy surface coating with autonomous and non-autonomous repair capabilities according to claim 3, characterized in that: the mass ratio of the vinyltriethoxysilane to the perester in the coupling agent is 2: 1.

5. an aluminum alloy surface coating with autonomous and non-autonomous repair capabilities according to claim 4, characterized in that: the nano-scale porous silicon dioxide is loaded with the composite corrosion inhibitor by a low-pressure infiltration method.

6. An aluminum alloy surface coating with autonomous and non-autonomous repair capabilities according to claim 5, characterized in that: the composite corrosion inhibitor is a mixture of imidazole, 1, 2, 4 triazole and benzotriazole.

7. An aluminum alloy surface coating having both autonomous and non-autonomous repair capabilities according to claim 5, characterized in that: the loading amount of the composite corrosion inhibitor is 60-70% of the weight percentage of the silicon dioxide.

8. An aluminum alloy surface coating with autonomous and non-autonomous repair capabilities according to claim 6, characterized in that: in the composite corrosion inhibitor, the weight ratio of imidazole, 1, 2, 4 triazole and benzotriazole is 3: 2: 1.