阅读说明：本技术 一种提高马氏体耐热钢耐二氧化碳腐蚀的方法 (Method for improving carbon dioxide corrosion resistance of martensite heat-resistant steel ) 是由 魏芳芳 石全强 赵英军 刘潇 唐萌 于 2020-07-10 设计创作，主要内容包括：本发明属于金属表面处理技术领域,具体为一种提高马氏体耐热钢耐二氧化碳腐蚀的方法。该方法包括以下步骤：(1)表面预处理：试样用150号、240号、400号和600号金相砂纸逐级打磨、倒角,然后对其进行表面喷沙,最后通过酒精和丙酮清洗后烘干；(2)将氧化物涂层配料在1350±50℃高温熔融,充分反应后水冷,通过球磨得到二氧化硅粉末；(3)将氧化物粉末与无水乙醇混合,喷涂于金属表面,烘干后通过固化反应在700℃±50℃烧结10min,制备氧化物涂层。采用本发明方法在耐热钢表面进行表面处理,能够有效的提高马氏体耐热钢的耐二氧化碳腐蚀性能,延长马氏体耐热钢材料的使用寿命。(The invention belongs to the technical field of metal surface treatment, and particularly relates to a method for improving carbon dioxide corrosion resistance of martensite heat-resistant steel. The method comprises the following steps: (1) surface pretreatment: the sample is polished and chamfered step by using No. 150, No. 240, No. 400 and No. 600 metallographic abrasive paper, then the surface of the sample is sandblasted, and finally the sample is cleaned by alcohol and acetone and dried; (2) melting the oxide coating ingredients at 1350 +/-50 ℃, fully reacting, cooling by water, and performing ball milling to obtain silicon dioxide powder; (3) mixing the oxide powder with absolute ethyl alcohol, spraying the mixture on the surface of metal, drying the mixture, and sintering the mixture for 10min at 700 +/-50 ℃ through a curing reaction to prepare the oxide coating. By adopting the method of the invention to carry out surface treatment on the surface of the heat-resistant steel, the carbon dioxide corrosion resistance of the martensite heat-resistant steel can be effectively improved, and the service life of the martensite heat-resistant steel material is prolonged.)

1. A method for improving the carbon dioxide corrosion resistance of martensite heat-resistant steel is characterized in that an oxide coating is prepared on the surface of the heat-resistant steel through plasma sintering.

2. The method of improving the carbon dioxide corrosion resistance of a martensitic heat-resistant steel as claimed in claim 1 wherein the oxide coating formulation has a major component of SiO₂And Al₂O₃Wherein: SiO is more than or equal to 60 weight percent₂≤75wt％，10wt％≤Al₂O₃≤15wt％。

3. The method of improving the carbon dioxide corrosion resistance of a martensitic heat-resistant steel as claimed in claim 2 wherein the oxide coating formulation further comprises: ZrO not greater than 4 wt%₂≤8wt％，2wt％≤TiO₂≤6wt％，1wt％≤Na₂O≤4wt％，1wt％≤KNO₃≤3wt％。

4. The method for improving the carbon dioxide corrosion resistance of the martensitic heat-resistant steel as claimed in claim 2 or 3, wherein the oxide coating is melted at a high temperature of 1350 ± 50 ℃, cooled after the reaction, and prepared into powder by ball milling.

5. The method for improving the carbon dioxide corrosion resistance of martensitic heat-resistant steel as claimed in claim 1, wherein the heat-resistant steel is 9-12% Cr martensitic heat-resistant steel.

6. The method for improving the carbon dioxide corrosion resistance of martensitic heat-resistant steel as claimed in claim 5, wherein the chemical composition of the heat-resistant steel is, in weight percent: c is more than or equal to 0.05 percent and less than or equal to 0.45 percent, Si is more than or equal to 0 percent and less than or equal to 4 percent, Cr is more than or equal to 8 percent and less than or equal to 12 percent, W is more than or equal to 0 percent and less than or equal to 2 percent, Mn is more than 0 percent and less than or equal to 1.0 percent, Ta and Nb are more than 0 percent and less than or equal to 0.3 percent, V is more than 0 percent and less.

7. The method for improving the carbon dioxide corrosion resistance of martensitic heat-resistant steel as claimed in claim 1, wherein carbon dioxide is in a supercritical state at a temperature of 100 ℃ to 650 ℃ and a pressure of 7.5MPa to 30 MPa.

8. The method for improving the carbon dioxide corrosion resistance of martensitic heat-resistant steel according to any one of claims 1 to 7, characterized by the specific steps of:

(1) surface pretreatment: firstly, grinding and chamfering samples step by using No. 150, No. 240, No. 400 and No. 600 metallographic abrasive paper, then carrying out surface sand blasting on the samples, and finally drying the samples after cleaning the samples by using alcohol and acetone;

(2) melting the oxide coating ingredients at 1350 +/-50 ℃, fully reacting, cooling by water, and performing ball milling to obtain oxide coating powder with the particle size of 50-100 nm;

(3) mixing oxide coating powder and absolute ethyl alcohol according to the weight ratio (1.5-2): 1, mixing, spraying on the surface of martensite heat-resistant steel, drying, and sintering at 700 +/-50 ℃ for 5-15 min through a curing reaction to prepare an oxide coating, wherein the thickness of the oxide coating is 20-50 mu m.

Technical Field

The invention belongs to the technical field of metal surface treatment, and particularly relates to a method for improving carbon dioxide corrosion resistance of martensite heat-resistant steel.

Background

At present, the problems of low utilization efficiency of traditional fossil fuels, serious pollutant emission and the like caused by the traditional fossil fuels are solved, and the novel efficient supercritical carbon dioxide power cycle system takes the advantages of high efficiency, small equipment volume, small water consumption and the like as research hotspots and has wide application prospects in the fields of ship power, photo-thermal power generation, nuclear power, coal-fired power generation, waste heat utilization and the like. Since the 21 st century, design optimization of a carbon dioxide power cycle system and relevant basic research of important equipment and parts thereof are developed in the fields of nuclear power, photo-thermal power generation, coal-fired power generation and the like by global research institutes and colleges. In a novel power cycle system, the corrosion resistance of a material under a severe supercritical carbon dioxide environment becomes one of the key problems to be solved urgently.

The heat-resistant steel has good high-temperature strength, plasticity and high-temperature mechanical property stability and is widely applied to nuclear power, chemical industry, petroleum and other industrial departments. The 9-12% Cr martensitic heat-resistant steel is based on the traditional martensitic heat-resistant steel, and the lasting strength of the martensitic heat-resistant steel is obviously improved by optimizing chemical components and a heat treatment process. The 9-12% Cr martensite heat-resistant steel has excellent comprehensive performance and can be used as a structural material of important equipment and components of a supercritical carbon dioxide circulation system. However, the harsh working environment (high temperature, carbonization and corrosion) in the supercritical carbon dioxide system provides a new challenge for the service performance of the 9-12% Cr martensite heat-resistant steel structure material, and the carbon dioxide corrosion resistance of the structural material needs to be further improved along with the more harsh corrosive environment brought by the improvement of the service temperature of the equipment.

The carbon dioxide corrosion resistance of the 9-12% Cr heat-resistant steel can be further improved by a metal material surface modification process. Researches show that the oxide coating, especially silicon dioxide, has unique chemical inertness and stability, can form good chemical combination with a metal material substrate, is relatively low in price, has better interface spalling resistance than the traditional coating, shows excellent carbon dioxide high-temperature oxidation resistance and attracts much attention, but few reports about the corrosion resistance of the silicon dioxide coating in a supercritical carbon dioxide environment at home and abroad are available. Therefore, it is important to research the corrosion performance of the oxide coating in the supercritical carbon dioxide environment and ensure that the coating and the metal matrix have strong adhesive force without peeling, thereby achieving the purpose of protecting the metal matrix.

Disclosure of Invention

The invention aims to provide a method for improving the carbon dioxide corrosion resistance of martensite heat-resistant steel, which is characterized in that an oxide coating mainly comprising silicon dioxide is prepared on the surface of the heat-resistant steel, so that the carbon dioxide corrosion resistance of the martensite heat-resistant steel can be effectively improved, and the service life of the martensite heat-resistant steel material is prolonged.

The technical scheme of the invention is as follows:

a method for improving the carbon dioxide corrosion resistance of martensite heat-resistant steel is to prepare an oxide coating on the surface of the heat-resistant steel by plasma sintering.

The method for improving the carbon dioxide corrosion resistance of the martensitic heat-resistant steel comprises the following step of mixing the oxide coating with SiO as a main component₂And Al₂O₃Wherein: SiO is more than or equal to 60 weight percent₂≤75wt％，10wt％≤Al₂O₃≤15wt％。

The method for improving the carbon dioxide corrosion resistance of the martensitic heat-resistant steel also comprises the following steps of: ZrO not greater than 4 wt%₂≤8wt％，2wt％≤TiO₂≤6wt％，1wt％≤Na₂O≤4wt％，1wt％≤KNO₃≤3wt％。

The method for improving the carbon dioxide corrosion resistance of the martensite heat-resistant steel comprises the steps of melting an oxide coating at the high temperature of 1350 +/-50 ℃, carrying out water cooling after reaction, and preparing powder through ball milling.

According to the method for improving the carbon dioxide corrosion resistance of the martensite heat-resistant steel, the martensite heat-resistant steel is 9-12% of Cr.

The method for improving the carbon dioxide corrosion resistance of the martensite heat-resistant steel comprises the following chemical components in percentage by weight: c is more than or equal to 0.05 percent and less than or equal to 0.45 percent, Si is more than or equal to 0 percent and less than or equal to 4 percent, Cr is more than or equal to 8 percent and less than or equal to 12 percent, W is more than or equal to 0 percent and less than or equal to 2 percent, Mn is more than 0 percent and less than or equal to 1.0 percent, Ta and Nb are more than 0 percent and less than or equal to 0.3 percent, V is more than 0 percent and less.

The method for improving the carbon dioxide corrosion resistance of the martensite heat-resistant steel has the carbon dioxide in a supercritical state, the temperature of 100-650 ℃ and the pressure of 7.5-30 MPa.

The method for improving the carbon dioxide corrosion resistance of the martensite heat-resistant steel comprises the following specific steps:

(1) surface pretreatment: firstly, grinding and chamfering samples step by using No. 150, No. 240, No. 400 and No. 600 metallographic abrasive paper, then carrying out surface sand blasting on the samples, and finally drying the samples after cleaning the samples by using alcohol and acetone;

(2) melting the oxide coating ingredients at 1350 +/-50 ℃, fully reacting, cooling by water, and performing ball milling to obtain oxide coating powder with the particle size of 50-100 nm;

(3) mixing oxide coating powder and absolute ethyl alcohol according to the weight ratio (1.5-2): 1, mixing, spraying on the surface of martensite heat-resistant steel, drying, and sintering at 700 +/-50 ℃ for 5-15 min through a curing reaction to prepare an oxide coating, wherein the thickness of the oxide coating is 20-50 mu m.

The design idea of the invention is as follows:

the design idea of the invention is to fully utilize the high-temperature stability of the main component silicon dioxide in the coating, and the coating is not easy to carbonize and crystallize in the supercritical carbon dioxide environment, thereby avoiding the occurrence of premature failure of the coating due to carbonization and crystallization. In addition, the optimized alumina component in the coating effectively improves the thermal expansion coefficient of the coating and ensures the good combination of the coating and the martensite heat-resistant steel.

The invention has the advantages and beneficial effects that:

the invention adopts a method of prefabricating a layer of silicon-oxygen tetrahedron [ SiO ] with an intrinsic structure on the surface of a martensite heat-resistant steel material₄]With a coating of silica oxide, thereby separating supercritical carbon dioxide from martensiteThe contact of hot steel materials effectively protects the martensite heat-resistant steel matrix from oxidative corrosion and carbonization in a carbon dioxide corrosion environment, and the oxide coating has good binding force with the martensite heat-resistant steel matrix and is not easy to peel off, so that the oxide coating is very suitable for being used as a protective coating of the martensite heat-resistant steel in a supercritical carbon dioxide corrosion environment. In addition, the sintering temperature is 700 +/-50 ℃, the sintering time is 10min, the temperature is lower than the tempering temperature of the material, the microstructure and the mechanical property of the martensite heat-resistant steel material are not influenced, the supercritical carbon dioxide corrosion resistance of the martensite heat-resistant steel material is effectively improved, and the service life of the martensite heat-resistant steel material is prolonged.

Drawings

FIG. 1 is a cross-sectional view of the oxide coating prepared on the surface of example 1.

FIG. 2 is the cross-sectional profile of example 1 after 1000 hours of oxidative corrosion at 600 ℃ and 15MPa with supercritical carbon dioxide.

FIG. 3 is a cross-sectional profile of comparative example 1 after 1000 hours of oxidative corrosion at 600 ℃ and 15MPa with supercritical carbon dioxide.

FIG. 4 is a cross-sectional profile of comparative example 2 after 1000 hours of oxidative corrosion at 600 ℃ and 15MPa with supercritical carbon dioxide.

Detailed Description

In the specific implementation process, the invention provides a method for preparing an oxide coating mainly containing silicon dioxide on the surface of martensite heat-resistant steel so as to improve the carbon dioxide corrosion resistance of the martensite heat-resistant steel material.

The following examples further describe the invention.