阅读说明：本技术 一种电化学-浸渍协同制备石墨耐高温复合涂层的方法 (Method for preparing graphite high-temperature-resistant composite coating through electrochemistry-impregnation cooperation ) 是由 吴相福 陈香萍 田家利 邓达琴 洪文晶 李海航 李江标 刘春根 邓聪秀 于 2020-07-24 设计创作，主要内容包括：本发明提供了一种电化学-浸渍协同制备石墨耐高温复合涂层的方法,其特征在于,先将石墨基材表面进行预处理,然后在基体悬浮液中进行电化学沉积SiC/Si/C涂层,置于烘箱中烘干表面溶剂,之后浸渍在磷酸盐涂料中或者用磷酸盐涂料刷涂,再将石墨基材进行预温处理,最后烧结,即可在石墨基材上形成耐高温复合涂层。该耐高温涂层具有良好的抗氧化作用,对石墨基材起到保护作用。(The invention provides a method for preparing a graphite high-temperature-resistant composite coating by electrochemistry-dipping synergy, which is characterized by pretreating the surface of a graphite substrate, then electrochemically depositing a SiC/Si/C coating in a matrix suspension, placing the SiC/Si/C coating in an oven to dry a surface solvent, then dipping the SiC/Si/C coating in a phosphate coating or brushing the surface solvent with the phosphate coating, then preheating the graphite substrate, and finally sintering to form the high-temperature-resistant composite coating on the graphite substrate. The high-temperature resistant coating has good antioxidation and plays a role in protecting the graphite substrate.)

1. A method for preparing a graphite high-temperature-resistant composite coating through electrochemistry-dipping synergy is characterized by comprising the steps of pretreating the surface of a graphite base material, then carrying out electrochemical deposition on a SiC/Si/C coating in a matrix suspension, placing the SiC/Si/C coating in an oven to dry a surface solvent, then dipping the SiC/Si/C coating in a phosphate coating or brushing the surface solvent with the phosphate coating, then carrying out preheating treatment on the graphite base material, and finally sintering to form the high-temperature-resistant composite coating on the graphite base material.

2. The method for preparing the graphite high-temperature-resistant composite coating through electrochemical-impregnation synergy according to claim 1, wherein the matrix suspension comprises 8-15g/L of binder, 15-25g/L of silicon carbide, 5-10g/L of nano silicon powder, 3-6g/L of graphite powder, 1-3g/L of surfactant and 9-16g/L of regulator, and the balance is added to 1L by using solvent.

3. The method for electrochemical-impregnation synergetic preparation of the graphite high temperature resistant composite coating according to claim 1, wherein the phosphate coating comprises 35-45 w/v% of phosphate, 1-3 w/v% of nano alumina, 2-4 w/v% of silica, 1-3 w/v% of surfactant and 48-61 w/v% of solvent.

4. The method for electrochemical-impregnation synergetic preparation of the graphite high-temperature resistant composite coating according to claim 2, wherein the binder is one or more of phenolic resin, polyvinylpyrrolidone and epoxy resin.

5. The method for preparing the graphite high-temperature resistant composite coating through electrochemical-impregnation synergy according to claim 2 or 3, wherein the surfactant is one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, alkyl phosphate ester salt and branched-chain fatty alcohol phosphate ester salt.

6. The method for the electrochemical-impregnation synergetic preparation of the graphite high-temperature resistant composite coating according to claim 2, wherein the modifier is aluminum oxide and aluminum phosphate.

7. The method for electrochemical-impregnation synergetic preparation of the graphite high-temperature resistant composite coating according to claim 2 or 3, wherein the solvent is absolute ethyl alcohol or water.

8. The method for preparing the graphite high-temperature-resistant composite coating through the cooperation of electrochemical impregnation and impregnation as claimed in claim 1, wherein the baking is carried out at the temperature of 150-200 ℃ for 20-30 min.

9. The method for preparing the graphite high-temperature-resistant composite coating through the cooperation of electrochemistry and impregnation according to claim 1, wherein the pre-temperature treatment condition is 80-100 ℃, and the temperature is kept for 20-30 min.

10. The method for preparing the graphite high-temperature-resistant composite coating through the cooperation of electrochemical impregnation and sintering as claimed in claim 1, wherein the sintering is carried out by putting the coated graphite substrate into a high-temperature-resistant container, raising the temperature to 1900-2300 ℃ at a temperature-raising speed of 10-15 ℃/min, keeping the temperature for 60min under the inert gas condition, and lowering the temperature to room temperature at a speed of 10-15 ℃/min.

Technical Field

The invention relates to a method for preparing a graphite high-temperature-resistant composite coating through electrochemistry-impregnation synergy, and belongs to the technical field of graphite high-temperature coatings.

Background

Graphite has the characteristics of high density and high strength, is a good high-temperature structural material, and can be used as nuclear graphite, an electrode for electric spark machining, a structural material for rocket technology, aluminum plating and the like. Graphite has wide application in many occasions, and particularly has good high-temperature strength under high-temperature conditions. However, the graphite is oxidized rapidly in the presence of oxygen, which seriously affects the service performance and service life, and therefore, it is necessary to improve the oxidation resistance of graphite. It is common practice to provide a coating on the graphite substrate to improve the oxidation resistance of the graphite.

Disclosure of Invention

The invention provides a method for preparing a high-temperature-resistant composite coating by electrochemical-impregnation synergy, which can effectively solve the problems.

The invention is realized by the following steps:

a method for preparing a graphite high-temperature-resistant composite coating through electrochemistry-dipping cooperation comprises the steps of pretreating the surface of a graphite base material, carrying out electrochemical deposition on a SiC/Si/C coating in a matrix suspension, placing the coating in a drying oven to dry a surface solvent, dipping the coating in a phosphate coating or brushing the coating with the phosphate coating, carrying out preheating treatment on the graphite base material, and finally sintering to form the high-temperature-resistant composite coating on the graphite base material.

As a further improvement, the matrix suspension comprises 8-15g/L of binder, 15-25g/L of silicon carbide, 5-10g/L of nano silicon powder, 3-6g/L of graphite powder, 1-3g/L of surfactant, 9-16g/L of regulator, and the balance of solvent added to 1L.

As a further improvement, the phosphate coating comprises 35-45 w/v% of phosphate, 1-3 w/v% of nano alumina, 2-4 w/v% of silicon dioxide, 1-3 w/v% of surfactant and 48-61 w/v% of solvent.

As a further improvement, the binder is one or more of phenolic resin, polyvinylpyrrolidone and epoxy resin.

As a further improvement, the surfactant is one or more of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, alkyl phosphate ester salt and branched-chain fatty alcohol phosphate ester salt.

As a further improvement, the modifier is alumina and aluminum phosphate.

As a further improvement, the solvent is absolute ethyl alcohol or water.

As a further improvement, the baking is carried out for 20-30min under the conditions of 150-200 ℃.

As a further improvement, the preheating treatment condition is 80-100 ℃, and the temperature is kept for 20-30 min.

As a further improvement, the sintering is to put the graphite substrate with the coating into a high-temperature resistant container, raise the temperature to 1900-.

The invention has the beneficial effects that:

according to the high-temperature-resistant composite coating on the graphite substrate prepared by the invention, the silicon carbide, the silicon powder, the graphite powder, the binder and the like in the first coating play a synergistic effect, the binder generates cracked carbon at high temperature and reacts with the matrix C, the graphite powder and the silicon powder to form the SiC coating, the SiC coating has strong bonding property with the matrix, is not easy to fall off and has good air tightness, the phosphate, the alumina and the silica in the phosphate coating of the second coating further improve the compactness of the coating, and meanwhile, the high-temperature-resistant composite coating has good adhesion with the first coating, ensures that the coating does not fall off, isolates oxygen, can play a good antioxidation effect in an aerobic environment at 1300 ℃, and plays a role in protecting the graphite substrate.

The method for preparing the high-temperature-resistant and antioxidant composite coating on the graphite substrate does not need complex instruments and equipment, is easy to operate, has good repeatability and is convenient for industrial production and application.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is an electron micrograph of a high temperature resistant coating on a graphite substrate provided in example 1 of the present invention.

FIG. 2 is an external view of a refractory coating on a graphite substrate provided in example 1 of the present invention.

FIG. 3 is a graph showing the comparison of the wear rates of the high temperature-resistant and oxidation-resistant coating on the graphite substrate provided in examples 1 to 4 of the present invention under different temperature conditions.

FIG. 4 is a graph comparing the wear rates of the high temperature resistant and oxidation resistant coatings on the graphite substrates provided in example 1 of the present invention and comparative examples 1-3 under different temperature conditions.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.