Flue gas low-temperature corrosion resistant composite material for boiler and preparation process of flue gas low-temperature corrosion resistant composite material

Abstract

The invention discloses a flue gas low-temperature corrosion resistant composite material for boilers and a preparation process thereof, and relates to the technical field of composites.The preparation method comprises the steps that azobisisobutyronitrile is added into a mixed monomer and stirred, and a prepolymer is obtained; taking glycidyl methacrylate, azobisisobutyronitrile and a mixed monomer, uniformly mixing, adding into the prepolymer, stirring and reacting to obtain the fluorine-containing polyacrylate. Adding fluororesin into propylene glycol methyl ether acetate, adding ceramic glaze powder, dispersing and ball-milling to obtain a pre-dispersed coating; taking fluorine-containing polyacrylate and ceramic glaze powder according to a mass ratio of (10-12): (6-8), dispersing and ball-milling to obtain a coating; and taking the coating, spraying the coating on the surface of the steel subjected to co-permeation treatment under the conditions that the gas delivery rate is 750-850 L / min, the feeding rate is 55-65 g / min and the spraying rate is 9-11 mm / s, and drying to obtain the composite material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to a composite material resistant to flue gas low-temperature corrosion for boilers and a preparation process thereof. BACKGROUND

[0002] In the modern salt-making field, boilers are the core equipment for heat supply, which provide high-temperature and high-pressure steam to heat brine, evaporate water, concentrate brine and cause salt precipitation; at present, an economizer is arranged at the tail flue of the boiler to utilize the waste heat of flue gas and further improve the energy utilization efficiency. However, due to the combustion of sulfur in fuel, sulfur dioxide and sulfur trioxide are generated, and sulfuric acid is formed by the reaction of the sulfur dioxide, sulfur trioxide and water vapor in the flue gas; when the temperature of the heating surface is relatively low, such as the economizer, flue and dust collector, the temperature of the heating surface is lower than the acid dew point, and the sulfuric acid vapor condenses to cause strong acid corrosion on the metal surface, which seriously affects the safe operation and service life of the equipment. Developing a new flue gas low-temperature corrosion resistant material can fundamentally solve the problem of flue gas low-temperature corrosion and is conducive to the utilization of flue gas waste heat and energy saving.

[0003] In order to solve the above problems, the present application provides a composite material resistant to flue gas low-temperature corrosion for boilers and a preparation process thereof. SUMMARY

[0004] The present application aims to provide a composite material resistant to flue gas low-temperature corrosion for boilers and a preparation process thereof to solve the problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: Step one: put perfluoro-octyl ethyl acrylate into butyl methacrylate, mix uniformly to obtain a mixed monomer; put azobis isobutyronitrile into the mixed monomer, stir to obtain a prepolymer; put glycidyl methacrylate, azobis isobutyronitrile and the mixed monomer, mix uniformly, add the prepolymer, stir and react to obtain fluorine-containing polyacrylate; Step two: put fluororesin into propylene glycol methyl ether acetate, add ceramic glaze powder, disperse, ball mill to obtain a pre-dispersed coating; disperse fluorine-containing polyacrylate and ceramic glaze powder, ball mill to obtain a coating; Step three: take the coating, spray it on the surface of the co-diffusion treated steel material, dry to obtain a composite material.

[0006] More preferably, the preparation process of the ceramic glaze powder is as follows: mix silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide and boron phosphate uniformly, react at a temperature of 1200-1300℃ for 30-40min, and ball mill to obtain the ceramic glaze powder.

[0007] The preparation process of the co-penetration treated steel material is more optimized, which comprises the following steps: taking antimony ingot and nickel wire, melting, casting, drawing, controlling the diameter of 4.5-5.5 mm, and obtaining the antimony-nickel wire; taking the steel material, performing surface grinding, polishing and ultrasonic cleaning, taking the antimony-nickel wire as the source material, vacuumizing, ion bombarding the surface of the steel material, introducing argon, reacting at the temperature of 1050-1150 DEG C for 3.5-4.5 hours, and cooling to obtain the co-penetration treated steel material.

[0008] More preferably, the mass ratio of the fluorine-containing polyacrylate and the ceramic glaze powder is (10-12):(6-8).

[0009] More preferably, in step three, the spraying process is that the gas conveying rate is 750-850 L / min, the feeding rate is 55-65 g / min, and the spraying rate is 9-11 mm / s.

[0010] More preferably, the mass ratio of the silicon dioxide, the magnesium oxide, the aluminum oxide, the iron oxide, the calcium oxide, the potassium oxide, the sodium oxide, the titanium dioxide and the boron phosphate is (48.5-49.5):(13-13.1):(36-36.2):(0.8-1):(0.1-0.3):(0.2-0.4):(0.07-0.09):(0.06-0.08):(0.05-0.15).

[0011] More preferably, the preparation process of the steel material comprises the following steps: taking carbon structural steel, heating to obtain molten carbon structural steel; adding metal chromium into the molten carbon structural steel, stirring uniformly, deoxidizing, removing slag, casting and forging to obtain the steel material.

[0012] More preferably, the mass ratio of the metal chromium and the molten carbon structural steel is (1.4-1.6):(99-101).

[0013] Compared with the prior art, the present application has the following beneficial effects: 1. The preparation of the co-penetration treated steel material comprises the following steps: adding alloying element chromium into carbon structural steel to obtain the steel material; and performing antimony-nickel co-penetration treatment on the surface of the steel material by the glow plasma metal infiltration technology to form a surface antimony-nickel alloy layer; wherein, the alloying element chromium forms a dense chromium oxide protective film on the surface of the carbon structural steel to isolate the carbon structural steel from corrosive substances and improve the resistance to low-temperature flue gas corrosion. The alloying elements antimony and nickel promote the corrosion process to occur preferentially in the surface antimony-nickel alloy layer through the noble metal effect, and the antimony and nickel form dense intermetallic compounds to improve the resistance to low-temperature flue gas corrosion; further, the corrosion product antimony oxide forms a dense oxide film, and the steel material still has the resistance to low-temperature flue gas corrosion after corrosion.

[0014] 2. The ceramic glaze powder is prepared by applying the excellent acid corrosion resistance of cordierite to the ceramic glaze powder, calculating and optimizing the ceramic glaze powder ratio, and selecting silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide and titanium dioxide in a mass ratio of (48.5-49.5):(13-13.1):(36-36.2):(0.8-1):(0.1-0.3):(0.2-0.4):(0.07-0.09):(0.06-0.08). Further adding boron phosphate, on the one hand, boron phosphate decomposes to form boron trioxide at high temperature, boron trioxide has strong fluxing effect, reduces the melting temperature and reduces the energy consumption; on the other hand, boron trioxide combines with the phosphorus pentoxide and silicon dioxide in the boron phosphate to form borophosphate and silicate glass network, thereby improving the compactness, bonding strength and chemical stability of the ceramic glaze powder, and improving the mechanical properties and corrosion resistance.

[0015] 3. The fluorine-containing polyacrylate is prepared by using azobis isobutyronitrile as an initiator, and using perfluoro octyl ethyl acrylate and butyl methacrylate as monomers to initiate chain polymerization reaction. The fluorine monomer perfluoro octyl ethyl acrylate and the non-fluorine monomer butyl methacrylate are copolymerized by free radicals. The fluorine atom in perfluoro octyl ethyl acrylate has extremely high electronegativity, so that perfluoro octyl ethyl acrylate itself presents low polarity and tends to migrate to the surface in the polymer system, thereby reducing the surface energy. The low surface energy of perfluoro octyl ethyl acrylate makes the fluorine-containing polyacrylate have excellent thermal stability, hydrophobicity and corrosion resistance. Glycidyl methacrylate is added, the epoxy group of glycidyl methacrylate participates in the polymerization reaction, and a crosslinking network is further formed by ring-opening reaction to improve the crosslinking degree and the bonding strength and mechanical properties of the fluorine-containing polyacrylate.

[0016] 4. The fluororesin pre-dispersed ceramic glaze powder is added to further improve the compatibility of the ceramic glaze powder and the fluorine-containing polyacrylate. The fluorine atom in the fluororesin itself has extremely high electronegativity, so that the fluororesin itself presents low polarity and tends to migrate to the surface in the filler system, thereby reducing the surface energy. The low surface energy of the fluororesin makes the fluororesin have excellent thermal stability, hydrophobicity and corrosion resistance. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present application will be described below. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0018] The source and model of the substance are not specially limited, and exemplarily include: The carbon structural steel has a model number of 2025, is provided by Shandong Yuxin Metal Material Co., Ltd., the metallic chromium has a model number of C0070019235, is provided by Nanjing Chemical Reagent Co., Ltd., the antimony ingot has a model number of B0087500, is provided by Wuhan Tuocai Technology Co., Ltd., the nickel wire has a model number of 2023103102, is provided by Shanghai Shiheng Alloy (Group) Co., Ltd., the silicon dioxide has a model number of S33549-500g, is provided by Shanghai Yuanye Bio-Technology Co., Ltd., the magnesium oxide has a model number of S24254-250g, is provided by Shanghai Yuanye Bio-Technology Co., Ltd., the aluminum oxide has a model number of A102002-500g, is provided by Shanghai Aladdin Bio-Chem Technology Co., Ltd., the iron oxide has a model number of S24050-500g, is provided by Shanghai Yuanye Bio-Technology Co., Ltd., the calcium oxide has a model number of C141333-500g, is provided by Shanghai Aladdin Bio-Chem Technology Co., Ltd., the titanium dioxide has a model number of T19842-500g, is provided by Shanghai Jitai Biochemical Technology Co., Ltd., the boron phosphate has a model number of M54685, is provided by Shanghai Maiery Biochemical Technology Co., Ltd., the perfluorooctyl ethyl acrylate has a model number of 03706, is provided by Wuhan Canos Technology Co., Ltd., the butyl methacrylate has a model number of M30423, is provided by Shanghai Maiery Biochemical Technology Co., Ltd., the glycidyl methacrylate has a model number of S60373-500g, is provided by Shanghai Yuanye Bio-Technology Co., Ltd., the fluororesin has a model number of 9010-75-7, is provided by Chongqing Ruiya Biological Technology Co., Ltd. Example 1: A preparation process of a composite material resistant to low-temperature corrosion of flue gas for a boiler; Step one: preparation of co-permeation treated steel S1: take the carbon structural steel, heat to obtain molten carbon structural steel; take the metallic chromium with a mass ratio of 1.4:99, add into the molten carbon structural steel, stir uniformly, deoxidize, remove slag, cast, forge to obtain the steel material; S2: take the antimony ingot and the nickel wire with a mass ratio of 49:51, smelt, cast, draw, control the diameter to be 4.5mm to obtain the antimony-nickel wire; take the steel material, perform surface grinding, polishing and ultrasonic cleaning, take the antimony-nickel wire as the source material, vacuumize, ion bombard the surface of the steel material, introduce argon gas, react for 3.5h at a temperature of 1050℃, cool to obtain the co-permeation treated steel; Step two: preparation of ceramic glaze powder Silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, boron phosphate were taken in a mass ratio of 48.5:13:36:0.8:0.1:0.2:0.07:0.06:0.05, mixed uniformly, reacted for 30 min under the condition of a temperature of 1200 DEG C, ball milled to obtain a ceramic enamel powder; Step three: preparation of the coating S1: 81 g of perfluoro-octyl ethyl acrylate was taken into 52 g of butyl methacrylate and mixed uniformly to obtain a mixed monomer; 0.06 g of azobis isobutyronitrile was taken into 33.25 g of the mixed monomer, stirred for 25 min under the condition of a temperature of 70 DEG C to obtain a prepolymer; 14 g of glycidyl methacrylate, 0.19 g of azobis isobutyronitrile and 99.75 g of the mixed monomer were mixed uniformly and added into the prepolymer, stirred, reacted for 19 h under the condition of a temperature of 65 DEG C, reacted for 1.5 h under the condition of a temperature of 105 DEG C to obtain a fluorine-containing polyacrylate; S2: 37 g of the fluorine resin was taken into 56 g of propylene glycol methyl ether acetate, the ceramic enamel powder prepared above was added, dispersed for 25 min, ball milled to obtain a pre-dispersed coating; the fluorine-containing polyacrylate and the ceramic enamel powder were taken in a mass ratio of 10:8, dispersed for 25 min, ball milled to obtain a coating; Step four: preparation of the composite material The coating was sprayed on the surface of the co-diffusion treated steel material under the condition of a gas delivery rate of 750 L / min, a feeding rate of 55 g / min and a spraying rate of 9 mm / s, dried to obtain a composite material.

[0019] Example 2: a preparation process of a composite material resistant to low-temperature corrosion of flue gas for a boiler; Step one: preparation of the co-diffusion treated steel material S1: carbon structural steel was heated to obtain molten carbon structural steel; 1.5 parts by mass of chromium metal was taken and added into the molten carbon structural steel, stirred uniformly, deoxidized, deslagged, cast and forged to obtain a steel material; S2: 50 parts by mass of antimony ingot and 50 parts by mass of nickel wire were taken, melted, cast, drawn and controlled to have a diameter of 5 mm to obtain antimony-nickel wire; the steel material was surface ground, polished and ultrasonic cleaned, the antimony-nickel wire was taken as a source material, the surface of the steel material was ion bombarded, argon was introduced, reacted for 4 h under the condition of a temperature of 1100 DEG C, cooled to obtain a co-diffusion treated steel material; Step two: preparation of the ceramic enamel powder Silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, boron phosphate were taken in a mass ratio of 49:13.05:36.1:0.9:0.2:0.3:0.08:0.07:0.1, mixed uniformly, reacted at a temperature of 1250°C for 35 min, ball milled to obtain a ceramic enamel powder; Step three: preparation of the coating S1: 83.5g of perfluoro-octyl ethyl acrylate was taken and added to 53g of butyl methacrylate, mixed uniformly to obtain a mixed monomer; 0.065g of azobis isobutyronitrile was taken and added to 34.13g of the mixed monomer, stirred at 75°C for 30 min to obtain a prepolymer; 15g of glycidyl methacrylate, 0.2g of azobis isobutyronitrile, 102.37g of the mixed monomer were mixed uniformly and added to the prepolymer, stirred, reacted at a temperature of 70°C for 20h; reacted at a temperature of 110°C for 2h to obtain a fluorine-containing polyacrylate; S2: 38g of the fluorine resin was taken and added to 57g of propylene glycol methyl ether acetate, the ceramic enamel powder prepared above was added, dispersed for 30 min, ball milled to obtain a pre-dispersed coating; the fluorine-containing polyacrylate and the ceramic enamel powder were taken in a mass ratio of 11:7, dispersed for 30 min, ball milled to obtain a coating; Step four: preparation of the composite material The coating was sprayed on the surface of the interstitial treatment steel at a gas delivery rate of 800L / min, a feeding rate of 60g / min, and a spraying rate of 10mm / s, dried to obtain a composite material.

[0020] Example 3: a preparation process of a composite material for resisting low-temperature corrosion of flue gas for a boiler; Step one: preparation of the interstitial treatment steel S1: carbon structural steel was heated to obtain molten carbon structural steel; metal chromium was taken in a mass ratio of 1.6:101 and added to the molten carbon structural steel, stirred uniformly, deoxidized, deslagged, cast, and forged to obtain a steel material; S2: antimony ingot and nickel wire were taken in a mass ratio of 51:49, melted, cast, and drawn to a diameter of 5mm to obtain antimony-nickel wire; the steel material was surface ground, polished, and ultrasonic cleaned, the antimony-nickel wire was taken as a source material, the surface of the steel material was ion bombarded, argon was introduced, reacted at a temperature of 1150°C for 4.5h, and cooled to obtain an interstitial treatment steel; Step two: preparation of the ceramic enamel powder Silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, boron phosphate were taken in a mass ratio of 49.5:13.1:36.2:1:0.3:0.4:0.09:0.08:0.15, mixed uniformly, reacted for 40 min under the condition of a temperature of 1300 ℃, ball-milled to obtain a ceramic enamel powder; Step three: preparation of the coating S1: 86 g of perfluoro-octyl ethyl acrylate was taken into 54 g of butyl methacrylate, mixed uniformly to obtain a mixed monomer; 0.07 g of azobis isobutyronitrile was taken into 35 g of the mixed monomer, stirred for 35 min under the condition of a temperature of 80 ℃ to obtain a prepolymer; 16 g of glycidyl methacrylate, 0.21 g of azobis isobutyronitrile, 105 g of the mixed monomer were mixed uniformly and added into the prepolymer, stirred, reacted for 21 h under the condition of a temperature of 75 ℃, reacted for 2.5 h under the condition of a temperature of 115 ℃ to obtain a fluorine-containing polyacrylate; S2: 39 g of the fluorine resin was taken into 58 g of propylene glycol methyl ether acetate, the ceramic enamel powder prepared above was added, dispersed for 35 min, ball-milled to obtain a pre-dispersed coating; the fluorine-containing polyacrylate and the ceramic enamel powder were taken in a mass ratio of 12:6, dispersed for 35 min, ball-milled to obtain a coating; Step four: preparation of the composite material The coating was sprayed on the surface of the steel material treated by the co-permeation under the condition of a gas delivery rate of 850 L / min, a feeding rate of 65 g / min, and a spraying rate of 11 mm / s, dried to obtain a composite material.

[0021] Comparative example 1: antimony-nickel co-permeation treatment was performed without adding antimony-nickel wires in step S2, and the rest was according to example 2; Step one: preparation of the steel material Carbon structural steel was taken, heated to obtain molten carbon structural steel; 1.5 g of chromium was taken in a mass ratio of 1.5:100 and added into the molten carbon structural steel, stirred uniformly, deoxidized, deslagged, cast, forged to obtain a steel material; Step two: preparation of the ceramic enamel powder Silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, boron phosphate were taken in a mass ratio of 49:13.05:36.1:0.9:0.2:0.3:0.08:0.07:0.1, mixed uniformly, reacted for 35 min under the condition of a temperature of 1250 ℃, ball-milled to obtain a ceramic enamel powder; Step three: preparation of the coating S1: take 83.5 g of perfluoro octyl ethyl acrylate into 53 g of butyl methacrylate, mix evenly to obtain a mixed monomer; take 0.065 g of azobis isobutyronitrile into 34.13 g of the mixed monomer, stir for 30 min at 75℃ to obtain a prepolymer; take 15 g of glycidyl methacrylate, 0.2 g of azobis isobutyronitrile, 102.37 g of the mixed monomer, mix evenly, add into the prepolymer, stir, react for 20 h at a temperature of 70℃; react for 2 h at a temperature of 110℃ to obtain a fluorine-containing polyacrylate; S2: take 38 g of fluorine resin into 57 g of propylene glycol methyl ether acetate, add the ceramic glaze powder prepared above, disperse for 30 min, ball mill to obtain a pre-dispersed coating; take the fluorine-containing polyacrylate and the ceramic glaze powder at a mass ratio of 11:7, disperse for 30 min, ball mill to obtain a coating; Step four: preparation of a composite material Take the coating, spray on the surface of a steel material at a gas delivery rate of 800 L / min, a feeding rate of 60 g / min, and a spraying rate of 10 mm / s, dry to obtain a composite material.

[0022] Comparative example 2: no boron phosphate is added, and the rest is according to example 2; Step one: preparation of a co-diffusion treated steel material S1: take carbon structural steel, heat to obtain molten carbon structural steel; take metal chromium at a mass ratio of 1.5:100 into the molten carbon structural steel, stir evenly, deoxidize, remove slag, cast, and forge to obtain a steel material; S2: take antimony ingot and nickel wire at a mass ratio of 50:50, melt, cast, and draw to control the diameter to 5 mm to obtain antimony-nickel wire; take the steel material, perform surface grinding, polishing, and ultrasonic cleaning, take the antimony-nickel wire as a source material, vacuumize, ion bombard the surface of the steel material, introduce argon gas, react for 4 h at a temperature of 1100℃, and cool to obtain a co-diffusion treated steel material; Step two: preparation of a ceramic glaze powder Take silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, and titanium dioxide at a mass ratio of 49:13.05:36.1:0.9:0.2:0.3:0.08:0.07, mix evenly, react for 35 min at a temperature of 1250℃, and ball mill to obtain a ceramic glaze powder; Step three: preparation of a coating S1: take 83.5 g of perfluoro octyl ethyl acrylate into 53 g of butyl methacrylate, mix evenly to obtain a mixed monomer; take 0.065 g of azobis isobutyronitrile into 34.13 g of the mixed monomer, stir for 30 min at 75℃ to obtain a prepolymer; take 15 g of glycidyl methacrylate, 0.2 g of azobis isobutyronitrile, 102.37 g of the mixed monomer, mix evenly, add into the prepolymer, stir, react for 20 h at a temperature of 70℃; react for 2 h at a temperature of 110℃ to obtain a fluorine-containing polyacrylate; S2: take 38 g of fluororesin into 57 g of propylene glycol methyl ether acetate, add the ceramic glaze powder prepared above, disperse for 30 min, ball mill to obtain a pre-dispersed coating; take the fluorine-containing polyacrylate and the ceramic glaze powder at a mass ratio of 11:7, disperse for 30 min, ball mill to obtain a coating; Step four: preparation of a composite material Take the coating, spray on the surface of the co-diffusion treated steel material at a gas delivery rate of 800 L / min, a feeding rate of 60 g / min, and a spraying rate of 10 mm / s, dry to obtain a composite material.

[0023] Comparative example 3: no perfluoro octyl ethyl acrylate is added, and the rest is according to example 2; Step one: preparation of a co-diffusion treated steel material S1: take carbon structural steel, heat to obtain molten carbon structural steel; take metal chromium at a mass ratio of 1.5:100 into the molten carbon structural steel, stir evenly, deoxidize, remove slag, cast, and forge to obtain a steel material; S2: take antimony ingot and nickel wire at a mass ratio of 50:50, melt, cast, and draw to control the diameter to 5 mm to obtain antimony-nickel wire; take the steel material, perform surface grinding, polishing, and ultrasonic cleaning, take the antimony-nickel wire as a source material, vacuumize, ion bombard the surface of the steel material, introduce argon gas, react for 4 h at a temperature of 1100℃, and cool to obtain a co-diffusion treated steel material; Step two: preparation of a ceramic glaze powder Take silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, and boron phosphate at a mass ratio of 49:13.05:36.1:0.9:0.2:0.3:0.08:0.07:0.1, mix evenly, react for 35 min at a temperature of 1250℃, and ball mill to obtain a ceramic glaze powder; Step three: preparation of a coating S1: take 53 g of butyl methacrylate, mix evenly to obtain a mixed monomer; take 0.065 g of azobis isobutyronitrile and add to 34.13 g of the mixed monomer, stir for 30 min at 75°C to obtain a prepolymer; take 15 g of glycidyl methacrylate and 0.2 g of azobis isobutyronitrile, add to 102.37 g of the mixed monomer, mix evenly, add to the prepolymer, stir, react for 20 h at a temperature of 70°C; react for 2 h at a temperature of 110°C to obtain a fluorine-containing polyacrylate; S2: take 38 g of fluororesin and add to 57 g of propylene glycol methyl ether acetate, add the ceramic glaze powder prepared above, disperse for 30 min, ball mill to obtain a pre-dispersed coating; take the fluorine-containing polyacrylate and the ceramic glaze powder in a mass ratio of 11:7, disperse for 30 min, ball mill to obtain a coating; Step four: preparation of a composite material Take the coating, spray on the surface of the co-diffusion treated steel material at a gas delivery rate of 800 L / min, a feeding rate of 60 g / min, and a spraying rate of 10 mm / s, dry to obtain a composite material.

[0024] Comparative example 4: no metal chromium is added, and the rest is according to example 2; Step one: preparation of a co-diffusion treated steel material S1: take carbon structural steel, heat to obtain molten carbon structural steel; stir evenly, deoxidize, remove slag, cast, and forge to obtain a steel material; S2: take antimony ingot and nickel wire in a mass ratio of 50:50, melt, cast, and draw to control the diameter to 5 mm to obtain antimony-nickel wire; take the steel material, perform surface grinding, polishing, and ultrasonic cleaning, take the antimony-nickel wire as a source material, vacuumize, ion bombard the surface of the steel material, introduce argon gas, react for 4 h at a temperature of 1100°C, and cool to obtain a co-diffusion treated steel material; Step two: preparation of a ceramic glaze powder Take silica, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, and boron phosphate in a mass ratio of 49:13.05:36.1:0.9:0.2:0.3:0.08:0.07:0.1, mix evenly, react for 35 min at a temperature of 1250°C, and ball mill to obtain a ceramic glaze powder; Step three: preparation of a coating S1: take 83.5 g of perfluoro octyl ethyl acrylate into 53 g of butyl methacrylate, mix evenly to obtain a mixed monomer; take 0.065 g of azobis isobutyronitrile into 34.13 g of the mixed monomer, stir for 30 min at 75℃ to obtain a prepolymer; take 15 g of glycidyl methacrylate, 0.2 g of azobis isobutyronitrile, 102.37 g of the mixed monomer, mix evenly, add into the prepolymer, stir, react for 20 h at a temperature of 70℃; react for 2 h at a temperature of 110℃ to obtain a fluorine-containing polyacrylate; S2: take 38 g of fluororesin into 57 g of propylene glycol methyl ether acetate, add the ceramic glaze powder prepared above, disperse for 30 min, ball mill to obtain a pre-dispersed coating; take the fluorine-containing polyacrylate and the ceramic glaze powder at a mass ratio of 11:7, disperse for 30 min, ball mill to obtain a coating; Step four: preparation of a composite material Take the coating, spray on the surface of the co-diffusion treated steel material at a gas delivery rate of 800 L / min, a feeding rate of 60 g / min, and a spraying rate of 10 mm / s, dry to obtain a composite material.

[0025] Comparative example 5: no fluororesin is added, and the rest is according to example 2; Step one: preparation of a co-diffusion treated steel material S1: take carbon structural steel, heat to obtain molten carbon structural steel; take metal chromium at a mass ratio of 1.5:100 into the molten carbon structural steel, stir evenly, deoxidize, remove slag, cast, and forge to obtain a steel material; S2: take antimony ingot and nickel wire at a mass ratio of 50:50, melt, cast, and draw to control the diameter to 5 mm to obtain an antimony-nickel wire; take the steel material, perform surface grinding, polishing, and ultrasonic cleaning, take the antimony-nickel wire as a source material, vacuumize, ion bombard the surface of the steel material, introduce argon gas, react for 4 h at a temperature of 1100℃, and cool to obtain a co-diffusion treated steel material; Step two: preparation of a ceramic glaze powder Take silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, and boron phosphate at a mass ratio of 49:13.05:36.1:0.9:0.2:0.3:0.08:0.07:0.1, mix evenly, react for 35 min at a temperature of 1250℃, and ball mill to obtain a ceramic glaze powder; Step three: preparation of a coating S1: Take 83.5 g of perfluoroalkyl ethyl acrylate and add it to 53 g of butyl methacrylate, mix well to obtain a mixed monomer; take 0.065 g of azobis isobutyronitrile and add it to 34.13 g of the mixed monomer, stir for 30 min at 75℃ to obtain a prepolymer; take 15 g of glycidyl methacrylate, 0.2 g of azobis isobutyronitrile, and 102.37 g of the mixed monomer, mix well, and add to the prepolymer, stir, and react at a temperature of 70℃ for 20 h; react at a temperature of 110℃ for 2 h to obtain a fluorine-containing polyacrylate; S2: Take 57 g of propylene glycol methyl ether acetate and add it to the ceramic glaze powder prepared above, disperse for 30 min, and ball mill to obtain a pre-dispersed coating; take the fluorine-containing polyacrylate and ceramic glaze powder in a mass ratio of 11:7, disperse for 30 min, and ball mill to obtain a coating; Step four: preparation of a composite material Take the coating and spray it on the surface of the co-diffusion treated steel material at a gas delivery rate of 800 L / min, a feeding rate of 60 g / min, and a spraying rate of 10 mm / s, dry, and obtain a composite material.

[0026] Experiment: Take the composite materials prepared in Examples 1-3 and Comparative Examples 1-5 and measure their performance; Corrosion resistance test Take the composite material, polish, polish, wash, dry, measure the area, and weigh; immerse it in a 50% sulfuric acid solution for 7 days, take it out, wash it, dry it, weigh it, and measure the weight loss per square meter after immersion by the weight loss method, i.e. the weight loss rate; Mechanical property test According to GB / T228.1-2021 "Metallic Materials Tensile Test Part 1: Room Temperature Test Method", the sample size is 50mmx25mmx6mm, and the tensile strength is measured by CMT5105 tensile testing machine; Table 1

[0027] Conclusion: By analyzing the experimental data above, the composite material prepared in Examples 1-3 has a lower weight loss rate in an acidic corrosion environment, a higher tensile strength, and excellent corrosion resistance and mechanical properties, and is suitable for use in a boiler flue gas low-temperature corrosion environment; the composite material prepared in Comparative Examples 1-5 has a higher weight loss rate in an acidic corrosion environment, a lower tensile strength, and poor corrosion resistance and mechanical properties.

[0028] Comparative analysis of Comparative Example 1 without antimony-nickel co-permeation treatment and Example 2 shows that the surface antimony-nickel alloy layer is formed on the surface of the steel material by co-permeation to improve the mechanical properties; the alloying elements antimony and nickel promote the corrosion process to occur preferentially in the surface antimony-nickel alloy layer through the noble metal effect, and the antimony and nickel form a dense intermetallic compound to improve the resistance to low-temperature flue gas corrosion; further, the corrosion product antimony oxide forms a dense oxide film, and the steel material still has the resistance to low-temperature flue gas corrosion after corrosion.

[0029] Comparative analysis of Comparative Example 2 without adding boron phosphate and Example 2 shows that the further addition of boron phosphate, on the one hand, boron phosphate decomposes to form boron trioxide under high-temperature environment, boron trioxide has strong fluxing effect, reduces the melting temperature, and reduces energy consumption; on the other hand, boron trioxide and the phosphorus pentoxide and silicon dioxide in boron phosphate combine to form borophosphate and silicate glass network to improve the density, bonding strength and chemical stability of the ceramic enamel powder, and improve the mechanical properties and corrosion resistance.

[0030] Comparative analysis of Comparative Example 3 without adding perfluoro-octyl ethyl acrylate and Example 2 shows that the fluorine atom in perfluoro-octyl ethyl acrylate has extremely high electronegativity, which makes perfluoro-octyl ethyl acrylate itself have low polarity, and it tends to migrate to the surface in the polymer system to reduce the surface energy; the low surface energy of perfluoro-octyl ethyl acrylate makes the fluorine-containing polyacrylate have excellent thermal stability, hydrophobicity and corrosion resistance.

[0031] Comparative analysis of Comparative Example 4 without adding metal molybdenum and Example 2 shows that the co-permeation treated steel material is prepared by adding alloying element chromium to the carbon structural steel to obtain the steel material; wherein the alloying element chromium forms a dense chromium oxide protective film on the surface of the carbon structural steel to isolate the carbon structural steel from corrosive substances and improve the resistance to low-temperature flue gas corrosion.

[0032] Comparative analysis of Comparative Example 5 without adding fluororesin and Example 2 shows that the addition of fluororesin pre-dispersed ceramic enamel powder further improves the compatibility of the ceramic enamel powder and the fluorine-containing polyacrylate; the fluorine atom in the fluororesin itself has extremely high electronegativity, which makes the fluororesin itself have low polarity, and it tends to migrate to the surface in the filler system to reduce the surface energy; the low surface energy of the fluororesin makes the fluororesin have excellent thermal stability, hydrophobicity and corrosion resistance.

[0033] It is apparent for a person skilled in the art that the present application is not limited to the details of the above described exemplary embodiments, but that it can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than the above description, and all changes coming within the meaning and equivalency range of the claims are intended to be embraced therein.

Claims

1. A process for the preparation of a composite material for resisting low-temperature flue gas corrosion in a boiler, characterized in that: It comprises the following steps: Step one: take perfluoro octyl ethyl acrylate into butyl methacrylate, mix evenly, get mixed monomer; take azobis isobutyronitrile into mixed monomer, stir, get prepolymer; take glycidyl methacrylate, azobis isobutyronitrile, mixed monomer, mix evenly, add into prepolymer, stir, react, get fluorine-containing polyacrylate; Step two: take fluororesin into propylene glycol methyl ether acetate, add ceramic glaze powder, disperse, ball mill, get pre-dispersed coating; take fluorine-containing polyacrylate, ceramic glaze powder, disperse, ball mill, get coating; Step three: take coating, spray on the surface of co-diffusion treated steel, dry, get composite material.

2. The preparation process of the composite material resistant to low-temperature flue gas corrosion for a boiler according to claim 1, characterized in that: The preparation process of the ceramic glaze powder is: take silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, boron phosphate, mix evenly, react for 30-40 min under the condition of temperature 1200-1300℃, ball mill, get ceramic glaze powder.

3. The preparation process of the composite material resistant to low-temperature flue gas corrosion for boilers according to claim 1, characterized in that: The preparation process of the co-diffusion treated steel is: take antimony ingot, nickel wire, smelt, cast, draw, control diameter 4.5-5.5mm, get antimony nickel wire; take steel, carry on surface grinding, polishing, ultrasonic cleaning, take antimony nickel wire as source material, vacuumize, ion bombard steel surface, pass in argon, react for 3.5-4.5h under the condition of temperature 1050-1150℃, cool, get co-diffusion treated steel.

4. The preparation process of the composite material resistant to low-temperature flue gas corrosion for boilers according to claim 1, characterized in that: The mass ratio of the fluorine-containing polyacrylate and the ceramic glaze powder is (10-12):(6-8).

5. The process for preparing a composite material for resisting low-temperature flue gas corrosion of a boiler according to claim 1, characterized in that: In step three, the spraying process is gas delivery rate 750-850L / min, feeding rate 55-65g / min, spraying rate 9-11mm / s.

6. The process for preparing a composite material for resisting low-temperature flue gas corrosion of a boiler according to claim 2, characterized in that: The mass ratio of the silicon dioxide, magnesium oxide, aluminum oxide, iron oxide, calcium oxide, potassium oxide, sodium oxide, titanium dioxide, boron phosphate is (48.5-49.5):(13-13.1):(36-36.2):(0.8-1):(0.1-0.3):(0.2-0.4):(0.07-0.09):(0.06-0.08):(0.05-0.15).

7. The process for preparing a composite material for resisting low-temperature flue gas corrosion of a boiler according to claim 3, characterized in that: The preparation process of the steel is: take carbon structural steel, heat, get molten carbon structural steel; take metal chromium into molten carbon structural steel, stir evenly, deoxidize, remove slag, cast, forge, get steel.

8. The process for preparing a composite material for resisting low-temperature flue gas corrosion of a boiler according to claim 7, characterized in that: The mass ratio of the metal chromium and the molten carbon structural steel is (1.4-1.6):(99-101).

9. A boiler-resistant flue gas low-temperature corrosion composite material prepared by the preparation process of claim 1-8.

Images