CN102503562B - Preparation method of carbon/carbon composite material anti-oxidation phosphate glass coating - Google Patents

Abstract

A preparation method of a carbon/carbon composite anti-oxidation phosphate glass coating, the main component of phosphate glass is phosphate, and phosphate has the advantages of non-toxicity, low price, environmental protection and good high temperature performance, and has attracted people's attention. The invention prepares a coating with good high-temperature oxidation resistance by modifying the phosphate glass. The high-temperature anti-oxidation coating is prepared by a solid sintering method and a brush coating method, which has the advantages of simple process, no need for expensive equipment, suitable for large-scale production, and the like. Moreover, the composite coating prepared by the invention has firm bonding, uniform thickness and no cracks; the composite coating has good oxidation resistance, and the oxidation weight loss is less than 0.5% after effectively protecting the C/C composite material at 1500 DEG C for 300 hours.

Description

Preparation method of a carbon/carbon composite material anti-oxidation phosphate glass coating

technical field

The invention relates to a preparation method of a carbon/carbon composite material surface coating, in particular to a preparation method of a carbon/carbon composite material oxidation-resistant phosphate glass coating.

Background technique

C/C composite material is a material reinforced by carbon fiber or graphite fiber with carbon as the matrix, and its overall system is composed of carbon elements [Liu Bin, Yi Maozhong, Xiong Xiang, etc. C/C composite anti-oxidation composite coating Preparation and properties [J]. Mining and Metallurgy Engineering, 2000, 20(8): 74-76]. Due to the advantages of light specific gravity, high specific strength, ablation resistance, wear resistance, and good high-temperature mechanical and thermal properties, C/C composite materials are widely used in aerospace, intercontinental missile end caps, rockets, etc. The fields of engine nozzles and aircraft brake discs have shown great advantages [Cheng Jiwei, Luo Ruiying, Wang Tianmin. Research status of high-temperature oxidation resistance of carbon/carbon composites [J]. Carbon Technology, 2001, 116(5): 28- 33]. However, as the temperature increases, the C/C composite material is easily oxidized and becomes the "bottleneck" of its application. In the presence of oxygen, when the temperature is higher than 400 ° C, the carbon/carbon composite material will be oxidized, and its The strength is greatly reduced or even completely lost, which limits the application of C/C composites in high temperature fields (above 1300 °C).

At present, the measures to prevent the oxidation of C/C composite materials mainly focus on the following two aspects: one is the internal anti-oxidation technology. It is mainly to carry out anti-oxidation treatment on carbon fiber and improve the matrix of C/C composite material. The second is the external coating anti-oxidation technology. By preparing a single or composite coating on the outside of the C/C composite material to prevent oxidation due to oxygen diffusion into the matrix, the high temperature oxidation resistance is improved.

Often a single coating cannot meet the long-term anti-oxidation requirements of carbon/carbon composite materials, so multi-layer composite coatings have become the first choice for people to solve high-temperature oxidation resistance of carbon/carbon composite materials. Generally, multi-layer composite coatings are ceramic coatings. The composite coating of layer and glass coating, due to the difference in thermal expansion between the substrate of the ceramic coating and the coating, defects such as microcracks will be formed in the coating, so that the oxidation resistance will be deteriorated, and the glass coating at high temperature It has the characteristics of low viscosity, wettability and thermal stability to fill these defects such as microcracks [Huang Jianfeng, Li Hejun, Xiong Xinbo, etc. Research progress in high temperature oxidation-resistant coatings of carbon/carbon composites [J]. New carbon materials, 2005 , 20(4):373-379], which can greatly increase the oxidation resistance temperature of C/C composites. Since the SiC ceramic coating has a matching thermal expansion coefficient with the substrate, and the formation of SiO ₂ after oxidation can better inhibit the outward diffusion of matrix carbon, it is widely used in the inner coating of C/C composite anti-oxidation coatings . The outer coating adopts phosphate glass coating. There are two main inhibitory effects of phosphide on high temperature oxidation of C/C composites: one is physical hindrance, the other is active point hindrance, and the oxygen bridge in the glass coating The key factor for maintaining the inhibitory effect in the presence and presence of phosphorus-containing compounds, oxidized phosphide glass is an effective outer surface coating for C/C composites [Hu Xinghua, Wu Mingbo, Zha Qingfang. Research progress in oxidation resistance of carbon/carbon composites [J]. Carbon, 2006, 127(3): 38-45].

At present, the glass coatings used for anti-oxidation are mainly boric acid glass series and phosphate glass. The main component of borate glass is B ₂ O ₃ , because B ₂ O ₃ has high sensitivity and volatility in humid environment, and its wettability will decrease with the increase of temperature, these shortcomings limit boric acid Application of salt glass coating in aerobic environment above 1000℃. Although borate glass has been improved, it is still not suitable for applications at extreme temperatures of 1500 °C.

Contents of the invention

The object of the present invention is to propose a method for preparing a carbon/carbon composite oxidation-resistant phosphate glass coating with silicon carbide as the transition layer and phosphate glass as the outer coating. The invention has simple preparation process, low cost, fast production cycle, and is suitable for large-scale production, and the composite coating prepared by the invention has uniform thickness, no cracks, firm combination, and good high-temperature oxidation resistance.

In order to achieve the above object, the technical scheme adopted in the present invention is:

1) Preparation of silicon carbide transition layer: grind and mix uniformly to make powder according to the mass ratio of Si powder: C powder: Al ₂ O ₃ powder: B ₂ O ₃ powder = 3-8: 1: 1: 1, and then put Put the 3D-carbon/carbon composite material into a graphite crucible, and add powder to completely embed the 3D-carbon/carbon composite material, put the graphite crucible into a vertical vacuum furnace, and pass in argon as a protective atmosphere, and then Control the temperature rise rate of the vertical vacuum furnace to 5-20°C/min, raise the furnace temperature from room temperature to 1800-2000°C, keep it warm for 3-5h, then lower it to room temperature at a rate of 5-20°C/min, and start Open the crucible after the furnace, take out the 3D-carbon/carbon composite material from the powder, clean it with absolute ethanol in ultrasonic waves, and obtain the carbon/carbon composite silicon carbide transition layer;

2) Preparation of phosphate glass powder: take chemically pure TiO ₂ powder, NH ₄ H ₂ PO ₄ powder, ZnO powder, Cr ₂ O ₃ powder, MnO ₂ powder, and mix according to TiO ₂ : NH ₄ H ₂ PO ₄ : ZnO : Cr ₂ O ₃ : MnO ₂ = 5-7: 3: 0-1: 0-1: 0-1 mass ratio in a ball mill, and then put it into an Al ₂ O ₃ crucible in a silicon molybdenum rod furnace Heating, the heating rate is 5-15°C/min. After raising the furnace temperature from room temperature to 1300-1500°C, keep it warm for 5-8h, then take it out as the furnace temperature drops to room temperature, mash it and put it into a ball mill for ball milling. 300 mesh sieves obtain glass powder;

3) Preparation of phosphate glass coating: mix glass powder and analytically pure AlPO ₄ powder according to the mass ratio of 0.5-5:1 to obtain powder, weigh 1-5g of powder and mix with 1-8ml of absolute ethanol Prepare a slurry for brushing, brush the slurry on the carbon/carbon composite silicon carbide transition layer, and then put it in a vacuum furnace protected by argon at 1300-1500°C, keep it warm for 10min-60min, and finally Take it out and cool to obtain the carbon/carbon composite anti-oxidation phosphate glass coating.

The Si powder, C powder, Al ₂ O ₃ powder and B ₂ O ₃ powder are all 300 mesh powders.

The density of the 3D-carbon/carbon composite material is 1.75g/cm ³ , the 3D-carbon/carbon composite material is processed into a small cube of 10×10×10mm ³ , and the surface treatment of grinding and chamfering is carried out , and then use absolute ethanol to clean it in an ultrasonic generator and dry it.

The main component of phosphate glass is phosphate. Phosphate has the advantages of non-toxicity, low price, environmental protection and good high-temperature performance, and has been valued by people. The present invention prepares a glass with good high-temperature oxidation resistance by modifying phosphate glass. coating. The high-temperature anti-oxidation coating is prepared by a solid sintering method and a brush coating method, which has the advantages of simple process, no need for expensive equipment, suitable for large-scale production, and the like. Moreover, the composite coating prepared by the invention has firm bonding, uniform thickness and no cracks; the composite coating has good oxidation resistance, and the oxidation weight loss is less than 0.5% after effectively protecting the C/C composite material at 1500 DEG C for 300 hours.

Description of drawings

Fig. 1 is a scanning electron microscope (SEM) photo of an oxidation-resistant phosphate glass coating of a carbon/carbon composite prepared in the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Example 1:

1) Preparation of silicon carbide transition layer: take 300-mesh Si powder, C powder, Al ₂ O ₃ powder and B ₂ O ₃ powder, according to Si powder: C powder: _{Al 2} O ₃ powder: _{B 2} O ₃ powder = 3 : 1:1:1 mass ratio grinding and mixing to make powder, then take the 3D-carbon/carbon composite material with a density of 1.75g/ ^cm3 , and process the 3D-carbon/carbon composite material into 10×10×10mm ³ small cubes, and the surface treatment of grinding and chamfering, and then cleaning it with absolute ethanol in an ultrasonic generator and then drying it, and putting the dried 3D-carbon/carbon composite material into a graphite crucible , and add powder to completely embed the 3D-carbon/carbon composite material, put the graphite crucible into a vertical vacuum furnace, and pass in argon as a protective atmosphere, and then control the heating rate of the vertical vacuum furnace to 10°C /min, after raising the furnace temperature from room temperature to 2000 °C, keep it warm for 3 hours, then lower it to room temperature at a rate of 10 °C/min, open the crucible after the furnace is turned on, take out the 3D-carbon/carbon composite material from the powder, and use The carbon/carbon composite silicon carbide transition layer is obtained after anhydrous ethanol is cleaned in ultrasonic wave;

2) Preparation of phosphate glass powder: take chemically pure TiO ₂ powder, NH ₄ H ₂ PO ₄ powder, ZnO powder, Cr ₂ O ₃ powder, MnO ₂ powder, according to TiO ₂ : NH ₄ H ₂ PO ₄ =7 The mass ratio of : 3 is evenly ball-milled in a ball mill, then put into an Al ₂ O ₃ crucible and heated in a silicon-molybdenum rod furnace with a heating rate of 10°C/min. After the furnace temperature is raised from room temperature to 1500°C, it is kept for 5h , and then take it out as the furnace temperature drops to room temperature, crush it and put it into a ball mill and pass it through a 300-mesh sieve to obtain glass powder;

3) Preparation of phosphate glass coating: mix glass powder and analytically pure _AlPO4 powder according to the mass ratio of 0.5:1 to obtain powder, weigh 3g of powder and mix with 5ml of absolute ethanol to prepare a brush coating slurry Brush the slurry on the carbon/carbon composite silicon carbide transition layer, then put it in a vacuum furnace with argon protection at 1500 ° C, keep it for 10 minutes, and finally take it out and cool it to get the carbon/carbon composite material. Oxidized phosphate glass coating.

Example 2:

1) Preparation of silicon carbide transition layer: take 300 mesh Si powder, C powder, Al ₂ O ₃ powder and B ₂ O ₃ powder, according to Si powder: C powder: _{Al 2} O ₃ powder: _{B 2} O ₃ powder = 4 : 1:1:1 mass ratio grinding and mixing to make powder, then take the 3D-carbon/carbon composite material with a density of 1.75g/ ^cm3 , and process the 3D-carbon/carbon composite material into 10×10×10mm ³ small cubes, and the surface treatment of grinding and chamfering, and then cleaning it with absolute ethanol in an ultrasonic generator and then drying it, and putting the dried 3D-carbon/carbon composite material into a graphite crucible , and add powder to completely embed the 3D-carbon/carbon composite material, put the graphite crucible into the vertical vacuum furnace, pass in argon as the protective atmosphere, and then control the heating rate of the vertical vacuum furnace to 5°C /min, after raising the furnace temperature from room temperature to 1800 °C, keep it warm for 5 hours, then lower it to room temperature at a rate of 20 °C/min, open the crucible after the furnace is turned on, take out the 3D-carbon/carbon composite material from the powder, and use The carbon/carbon composite silicon carbide transition layer is obtained after anhydrous ethanol is cleaned in ultrasonic waves;

2) Preparation of phosphate glass powder: take chemically pure TiO ₂ powder, NH ₄ H ₂ PO ₄ powder, ZnO powder, Cr ₂ O ₃ powder, MnO ₂ powder, and mix according to TiO ₂ : NH ₄ H ₂ PO ₄ : ZnO = Mass ratio of 6:3:1 is uniformly ball-milled in a ball mill, then placed in an Al ₂ O ₃ crucible and heated in a silicon-molybdenum rod furnace with a heating rate of 5°C/min, and the furnace temperature is raised from room temperature to 1400°C Finally, keep warm for 6.5 hours, then take it out as the furnace temperature drops to room temperature, smash it and put it into a ball mill, and pass it through a 300-mesh sieve to obtain glass powder;

3) Preparation of phosphate glass coating: mix glass powder and analytically pure _AlPO4 powder according to a mass ratio of 1:1 to obtain powder, weigh 1g of powder and mix with 1ml of absolute ethanol to prepare a brush coating slurry Brush the slurry on the carbon/carbon composite silicon carbide transition layer, then put it in a vacuum furnace with argon protection at 1300 ° C, keep it warm for 60 minutes, and finally take it out and cool it to get the carbon/carbon composite material. Oxidized phosphate glass coating.

Example 3:

1) Preparation of silicon carbide transition layer: take Si powder, C powder, Al ₂ O ₃ powder and B ₂ O ₃ powder of 300 mesh, according to Si powder: C powder: _{Al 2} O ₃ powder: _{B 2} O ₃ powder = 5 : 1:1:1 mass ratio grinding and mixing to make powder, then take the 3D-carbon/carbon composite material with a density of 1.75g/ ^cm3 , and process the 3D-carbon/carbon composite material into 10×10×10mm ³ small cubes, and the surface treatment of grinding and chamfering, and then cleaning it with absolute ethanol in an ultrasonic generator and then drying it, and putting the dried 3D-carbon/carbon composite material into a graphite crucible , and add powder to completely embed the 3D-carbon/carbon composite material, put the graphite crucible into the vertical vacuum furnace, pass in argon as the protective atmosphere, and then control the temperature rise rate of the vertical vacuum furnace to 15°C /min, after raising the furnace temperature from room temperature to 1900 °C, keep it warm for 4 hours, then lower it to room temperature at a rate of 5 °C/min, open the crucible after the furnace is turned on, take out the 3D-carbon/carbon composite material from the powder, and use The carbon/carbon composite silicon carbide transition layer is obtained after anhydrous ethanol is cleaned in ultrasonic wave;

2) Preparation of phosphate glass powder: take chemically pure TiO ₂ powder, NH ₄ H ₂ PO ₄ powder, ZnO powder, Cr ₂ O ₃ powder, MnO ₂ powder, and mix according to TiO ₂ : NH ₄ H ₂ PO ₄ : ZnO : Cr ₂ O ₃ : MnO ₂ = 5: 3: 1: 0.5: 0.5, the mass ratio is ball milled in a ball mill, and then put into an Al ₂ O ₃ crucible and heated in a silicon-molybdenum rod furnace with a heating rate of 12°C/ min, after raising the furnace temperature from room temperature to 1300°C, keep it warm for 8 hours, then take it out as the furnace temperature drops to room temperature, smash it into a ball mill and pass it through a 300-mesh sieve to obtain glass powder;

3) Preparation of phosphate glass coating: mix glass powder and analytically pure _AlPO4 powder according to a mass ratio of 5:1 to obtain powder, weigh 2g of powder and mix with 4ml of absolute ethanol to prepare a brush coating slurry Brush the slurry on the carbon/carbon composite silicon carbide transition layer, then put it in a vacuum furnace with argon protection at 1450°C, keep it warm for 30min, and finally take it out and cool it to get the carbon/carbon composite material. Oxidized phosphate glass coating.

Example 4:

1) Preparation of silicon carbide _transition layer: _take 300 mesh Si powder, C powder, _Al2O3 powder and _B2O3 powder, according to Si powder: C powder _{: Al2O3} powder: _B2O3 powder = ₇ : 1:1:1 mass ratio grinding and mixing to make powder, then take the 3D-carbon/carbon composite material with a density of 1.75g/ ^cm3 , and process the 3D-carbon/carbon composite material into 10×10×10mm ³ small cubes, and the surface treatment of grinding and chamfering, and then cleaning it with absolute ethanol in an ultrasonic generator and then drying it, and putting the dried 3D-carbon/carbon composite material into a graphite crucible , and add powder to completely embed the 3D-carbon/carbon composite material, put the graphite crucible into the vertical vacuum furnace, pass in argon as the protective atmosphere, and then control the heating rate of the vertical vacuum furnace to 12°C /min, after raising the furnace temperature from room temperature to 1850°C, keep it warm for 4.5h, then lower it to room temperature at a rate of 15°C/min, open the crucible after the furnace is turned on, and take out the 3D-carbon/carbon composite material from the powder, After cleaning with absolute ethanol in ultrasonic waves, a carbon/carbon composite silicon carbide transition layer is obtained;

2) Preparation of phosphate glass powder: take chemically pure TiO ₂ powder, NH ₄ H ₂ PO ₄ powder, ZnO powder, Cr ₂ O ₃ powder, MnO ₂ powder, and mix according to TiO ₂ : NH ₄ H ₂ PO ₄ : ZnO : Cr ₂ O ₃ : MnO ₂ = 5: 3: 0.5: 0.5: 1 mass ratio, ball milled in a ball mill evenly, then put into an Al ₂ O ₃ crucible and heat in a silicon-molybdenum rod furnace with a heating rate of 8°C/ min, after raising the furnace temperature from room temperature to 1450°C, keep it warm for 6 hours, then take it out as the furnace temperature drops to room temperature, smash it into a ball mill and pass it through a 300-mesh sieve to obtain glass powder;

3) Preparation of phosphate glass coating: mix glass powder and analytically pure _AlPO4 powder according to a mass ratio of 4:1 to obtain powder, weigh 4g of powder and mix with 6ml of absolute ethanol to prepare a brush coating slurry Brush the slurry on the carbon/carbon composite silicon carbide transition layer, then put it in a vacuum furnace with argon protection at 1350 ° C, keep it for 45 minutes, and finally take it out and cool it to get the carbon/carbon composite material. Oxidized phosphate glass coating.

Example 5:

1) Preparation of silicon carbide _transition layer _: take 300 mesh Si powder, C powder, _Al2O3 powder and _B2O3 powder, according to Si powder: C powder _{: Al2O3} powder: _B2O3 powder = ₈ : 1:1:1 mass ratio grinding and mixing to make powder, then take the 3D-carbon/carbon composite material with a density of 1.75g/ ^cm3 , and process the 3D-carbon/carbon composite material into 10×10×10mm ³ small cubes, and the surface treatment of grinding and chamfering, and then cleaning it with absolute ethanol in an ultrasonic generator and then drying it, and putting the dried 3D-carbon/carbon composite material into a graphite crucible , and add powder to completely embed the 3D-carbon/carbon composite material, put the graphite crucible into the vertical vacuum furnace, pass in argon as the protective atmosphere, and then control the heating rate of the vertical vacuum furnace to 20°C /min, after raising the furnace temperature from room temperature to 1950 °C, keep it warm for 3.5 hours, then lower it to room temperature at a rate of 12 °C/min, open the crucible after the furnace is turned on, and take out the 3D-carbon/carbon composite material from the powder, After cleaning with absolute ethanol in ultrasonic waves, a carbon/carbon composite silicon carbide transition layer is obtained;

2) Preparation of phosphate glass powder: take chemically pure TiO ₂ powder, NH ₄ H ₂ PO ₄ powder, ZnO powder, Cr ₂ O ₃ powder, MnO ₂ powder, and mix according to TiO ₂ : NH ₄ H ₂ PO ₄ : ZnO : Cr ₂ O ₃ : MnO ₂ = 5: 3: 0.5: 1: 0.5 mass ratio, ball milled in a ball mill evenly, and then put into an Al ₂ O ₃ crucible and heated in a silicon molybdenum rod furnace with a heating rate of 15°C/ min, after raising the furnace temperature from room temperature to 1350°C, keep it warm for 7 hours, then take it out as the furnace temperature drops to room temperature, crush it and put it into a ball mill and pass it through a 300-mesh sieve to obtain glass powder;

3) Preparation of phosphate glass coating: mix glass powder and analytically pure AlPO ₄ powder according to a mass ratio of 3:1 to obtain powder, weigh 5g of powder and mix with 8ml of absolute ethanol to prepare a brush coating slurry Brush the slurry on the carbon/carbon composite silicon carbide transition layer, then put it into a vacuum furnace with argon protection at 1400 ° C, keep it for 20 minutes, and finally take it out and cool it to get the carbon/carbon composite material. Oxidized phosphate glass coating.

It can be seen from Fig. 1 that the composite coating prepared by the present invention is firmly bonded, has uniform thickness and no cracks.

Claims (3)

1. A preparation method for a carbon/carbon composite anti-oxidation phosphate glass coating, characterized in that: 1) Preparation of silicon carbide transition layer: grind and mix uniformly according to the mass ratio of Si powder: C powder: Al ₂ O ₃ powder: B ₂ O ₃ powder = 3-8:1:1:1 to make a powder, and then put Put the 3D-carbon/carbon composite material into a graphite crucible, and add powder to completely embed the 3D-carbon/carbon composite material, put the graphite crucible into a vertical vacuum furnace, and pass in argon as a protective atmosphere, and then Control the temperature rise rate of the vertical vacuum furnace to 5-20°C/min, raise the furnace temperature from room temperature to 1800-2000°C, keep it warm for 3-5h, then lower it to room temperature at a rate of 5-20°C/min, and start Open the crucible after the furnace, take out the 3D-carbon/carbon composite material from the powder, clean it with absolute ethanol in ultrasonic waves, and obtain the carbon/carbon composite silicon carbide transition layer; 2) Preparation of phosphate glass powder: Take chemically pure TiO ₂ powder, NH ₄ H ₂ PO ₄ powder, ZnO powder, Cr ₂ O ₃ powder, MnO ₂ powder, according to TiO ₂ : NH ₄ H ₂ PO ₄ : ZnO : Cr ₂ O ₃ : MnO ₂ =5-7:3:0-1:0-1:0-1 mass ratio in the ball mill evenly ball milled, and then put into Al ₂ O ₃ crucible in silicon molybdenum rod furnace Heating, the heating rate is 5-15°C/min. After raising the furnace temperature from room temperature to 1300-1500°C, keep it warm for 5-8h, then take it out as the furnace temperature drops to room temperature, mash it and put it into a ball mill for ball milling. 300 mesh sieves obtain glass powder; 3) Preparation of phosphate glass coating: Mix glass powder with analytically pure AlPO ₄ powder at a mass ratio of 0.5-5:1 to obtain powder, weigh 1-5g of powder and mix with 1-8mL of absolute ethanol Prepare a slurry for brushing, brush the slurry on the carbon/carbon composite silicon carbide transition layer, and then put it in a vacuum furnace protected by argon at 1300-1500°C, keep it warm for 10min-60min, and finally Take it out and cool to obtain the carbon/carbon composite anti-oxidation phosphate glass coating. 2. the preparation method of carbon/carbon composite anti-oxidation phosphate glass coating according to claim 1, is characterized in that: described Si powder, C powder, Al ₂ O ₃ powder and B ₂ O ₃ powder all It is 300 mesh powder. 3. The preparation method of the carbon/carbon composite anti-oxidation phosphate glass coating according to claim 1, characterized in that: the density of the 3D-carbon/carbon composite is 1.75g/cm ³ , and the 3D - The carbon/carbon composite material is processed into a small cube of 10×10×10mm ³ , and its surface treatment is ground and chamfered, and then it is cleaned with absolute ethanol in an ultrasonic generator and dried.

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