A high temperature ablation resistant coating material and preparation method thereof

Abstract

The present invention relates to the technical field of polymer materials. The present invention proposes a high-temperature ablation-resistant coating material and a preparation method thereof, comprising the following materials: polysilazane resin, a composite ceramic material, carbon nanotubes and a filler; wherein the composite ceramic material is prepared from silicon carbide and graphene by a coating construction method. Compared with the existing high-temperature ablation-resistant coating material, the graphene-modified silicon carbide composite ceramic material has better dispersibility and better mechanical properties, and effectively improves the performance of the graphene-modified composite material. Polysilazane is used to improve the adhesion of the composite material, thereby greatly enhancing the ablation resistance and mechanical properties of the final high-temperature ablation-resistant coating material.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a high temperature ablation resistant coating material and a preparation method thereof. Background Art

[0002] With the rapid improvement of aircraft maneuverability, strike accuracy and penetration capability, the flight speed of aircraft has been greatly increased, and the aerodynamic heating environment faced by the missile body has become increasingly harsh. In particular, the thermal protection materials on the surface of the missile body have higher and higher requirements for heat protection performance. As a coating for the missile body, high-temperature resistant ablative coating materials have the characteristics of simple operation, strong adaptability and low cost, and have good application in the field of thermal protection of the missile body surface.

[0003] Currently, the main high-temperature ablation-resistant coating materials are epoxy resin, phenolic resin and silicone resin. Among them, silicone resin has a longer Si-O bond and a larger Si-O-Si bond angle. Its bond energy is much greater than the CC bond and CO bond energy in other polymers. It is sufficient to maintain the original physical properties over a wider temperature range, and thus has excellent flame retardancy, electrical insulation and corrosion resistance.

[0004] The ablation resistance mechanism of silicone materials mainly includes the following two points:

[0005] 1. Sublimation type ablation resistance, that is, decomposition and heat absorption. During the combustion process, the material is decomposed by heat, and the generated small molecules and water will sublimate, decompose or even ionize. At the same time, the material will melt and sublime by heat. This process consumes a lot of heat energy in the ablation process, preventing heat from invading the internal structure, so that the ablation resistance of the material can be improved.

[0006] 2. Carbon-type ablation resistance, that is, radiation heat dissipation. During the ablation process, the side groups of silicone break and the main chain structure is retained in the form of C and Si, and then a silicon-carbon layer is formed on the surface of the material to block heat transfer to the internal polymer material. At the same time, the silicon-carbon layer has good mechanical properties and can withstand the erosion of high-temperature airflow and hinder the expansion of ablation. The high blackness of the silicon-carbon layer also makes it have a higher infrared emissivity, transferring heat energy by thermal radiation.

[0007] After ablation, the ablation-resistant materials made of current polymer materials will form a carbon layer covering the surface of the ablation-resistant layer, which plays an important role in protecting and supporting the internal structure. Therefore, the mechanical properties of the carbon layer are also important for ablation-resistant materials. However, the ablation process is accompanied by a large number of violent melting, sublimation and cracking processes. The existing organosilicon has a large polarity difference with polymer materials, resulting in poor dispersibility in polymer materials. Therefore, the final material has limited improvement in ablation resistance.

[0008] Therefore, the existing technologies related to high temperature resistant ablation coating materials still need to be further improved. Summary of the invention

[0009] In view of the deficiencies in the prior art, the present invention proposes a high-temperature ablation-resistant coating material and a preparation method thereof, which solves the technical problem that the existing materials have poor dispersibility, resulting in low ablation resistance and mechanical strength.

[0010] In a first aspect, the present invention provides a high temperature resistant ablation coating material, comprising the following materials: polysilazane resin, composite ceramic material, carbon nanotubes and filler;

[0011] Wherein, the composite ceramic material is prepared from silicon carbide and graphene by a coating construction method.

[0012] On the basis of this technical solution, it is further preferred that the following materials are included in weight: 3-16 parts of polysilazane resin, 75-90 parts of composite ceramic material, 11-16 parts of carbon nanotubes and 22-40 parts of filler.

[0013] On the basis of this technical solution, it is further preferred that the nitrogen mass fraction of the polysilazane resin is 8%-35%, and the viscosity is 500-3200 mpa·s.

[0014] On the basis of this technical solution, it is further preferred that the filler is one of zirconium oxide, zirconium boride and titanium oxide.

[0015] On the basis of this technical solution, further preferably, the particle size of the carbon nanotubes is 20-40 nm.

[0016] On the basis of this technical solution, further preferably, the method for preparing the composite ceramic material comprises the following steps:

[0017] Silicon carbide is used as a substrate, the surface of the substrate is cleaned, graphene is dispersed in a solvent, and is evenly sprayed on the surface of the substrate, dried at 260-280° C., and a cross-linking agent is added to complete ceramicization to obtain the composite ceramic material.

[0018] On the basis of this technical solution, further preferably, the cross-linking agent includes vinyl triethoxy silane (VTES) or methyl triethoxy silane (MTES).

[0019] On the basis of this technical solution, it is further preferred that the cross-linking agent accounts for 2-5% of the mass of the substrate.

[0020] On the basis of this technical solution, further preferably, the solvent is polyethylene glycol and water, and the molar ratio of polyethylene glycol to water is 0.2-0.3:1.

[0021] In a second aspect, the present invention further provides a method for preparing the high temperature resistant ablation coating material according to the first aspect, comprising the following steps:

[0022] Grind the composite ceramic material, carbon nanotubes and fillers, mix them at high speed,

[0023] Finally, polysilazane resin is added, mixed at a low speed, and heated for curing to obtain the high temperature resistant ablation coating material.

[0024] On the basis of this technical solution, further, the high-speed mixing has a rotation speed of 2800-3000 r / min and a time of 1-1.5 h.

[0025] On the basis of this technical solution, further, the low-speed mixing has a rotation speed of 400-600 r / min and a time of 0.5-1 h.

[0026] On the basis of this technical solution, further, the heating and curing conditions are: oven treatment at 130-150°C for 1-2 hours, and then heating to 160-170°C for 1-2 hours.

[0027] On the basis of this technical solution, further preferably, the heating and curing further comprises pressurizing at 4 MPa at 130-150°C and pressurizing at 9 MPa at 160-170°C.

[0028] The high temperature ablation resistant coating material of the present invention has the following beneficial effects compared with the prior art:

[0029] The high temperature ablation resistant coating material of the present invention, polysilazane has excellent high temperature oxidation resistance, is an important component of the polymer matrix, can complete the room temperature curing of the resin system, and its unique Si-N polarity makes the adhesion of the composite material stronger. The addition of low-dimensional nano-reinforcement phase (carbon nanotubes and graphene) can significantly improve the mechanical properties of the material.

[0030] On the other hand, by dispersing graphene in a solvent composed of polyethylene glycol and water, graphene forms a graphene network in the solvent, and then using silicon carbide as a substrate, low-temperature ceramicization is completed through a coating construction method to obtain an ablation-resistant composite ceramic material. The graphene network can be effectively doped in silicon carbide, and the graphene-modified silicon carbide composite ceramic material has good dispersibility and better mechanical properties, which effectively improves the performance of the graphene-modified composite material and greatly enhances the ablation resistance and mechanical properties of the final high-temperature resistant ablation coating material.

[0031] Existing nanomaterials are difficult to disperse, and agglomeration and bridging effects reduce the density of composite materials, resulting in unsatisfactory improvement in mechanical properties. Therefore, the modified composite materials react with them to improve the problem of poor material dispersion.

[0032] The ablation-resistant material prepared by the present invention has good ablation-resistant performance and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 The present invention is a flow chart of the synthesis method of the high temperature ablation resistant coating material. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The present invention is based on the relevant technologies of existing high-temperature resistant ablative coating materials and proposes a high-temperature resistant ablative coating material, comprising the following materials: polysilazane resin, composite ceramic material, carbon nanotubes and filler. The composite ceramic material is prepared from silicon carbide and graphene by a coating construction method, and the composite ceramic material is obtained by low-temperature ceramicization. Compared with the existing high-temperature resistant ablative coating materials, the graphene-modified silicon carbide composite ceramic material has better dispersibility and better mechanical properties, which effectively improves the performance of the graphene-modified composite material, and obtains a high-temperature resistant ablative coating material with good corrosion resistance.

[0037] Example 1

[0038] A high-temperature ablation-resistant coating material comprises the following materials: 3 g of polysilazane resin, 75 g of composite ceramic material, 11 g of carbon nanotubes and 22 g of filler.

[0039] The polysilazane resin has a nitrogen mass fraction of 8% and a viscosity of 500 mpa·s.

[0040] Specifically, the filler is zirconium oxide.

[0041] Specifically, the carbon nanotube particle size is 20 nm.

[0042] Specifically, the method for preparing the composite ceramic material comprises the following steps:

[0043] Silicon carbide is used as a substrate, the surface of the substrate is cleaned, graphene is dispersed in a solvent, and is evenly sprayed on the surface of the substrate, dried at 260-280° C., and a cross-linking agent is added to complete ceramicization to obtain the composite ceramic material.

[0044] Specifically, the solvent is polyethylene glycol and water, and the molar ratio of polyethylene glycol to water is 0.2:1.

[0045] Specifically, the cross-linking agent includes VTES.

[0046] Specifically, the crosslinking agent accounts for 3% of the mass of the substrate.

[0047] The preparation method of the high temperature resistant ablation coating material is as follows Figure 1 As shown, the following steps are included:

[0048] Grind the composite ceramic material, carbon nanotubes and fillers, mix them at high speed,

[0049] Finally, polysilazane resin is added, mixed at a low speed, and heated for curing to obtain the high temperature resistant ablation coating material.

[0050] More specifically, the high-speed mixing has a rotation speed of 2800 r / min and a time of 1 h.

[0051] More specifically, the low-speed mixing has a rotation speed of 400 r / min and a time of 0.5 h.

[0052] More specifically, the heating and curing conditions are: oven treatment at 130°C for 1 hour, then heating to 160°C for 1 hour.

[0053] More specifically, the heat curing further includes applying a pressure of 4 MPa at 130° C. and applying a pressure of 9 MPa at 160° C.

[0054] Example 2

[0055] A high-temperature ablation-resistant coating material comprises the following materials: 16 g of polysilazane resin, 90 g of composite ceramic material, 16 g of carbon nanotubes and 40 g of filler.

[0056] The polysilazane resin has a nitrogen mass fraction of 35% and a viscosity of 3200 mpa·s.

[0057] Specifically, the filler is zirconium boride.

[0058] Specifically, the carbon nanotube particle size is 20 nm.

[0059] Specifically, the method for preparing the composite ceramic material comprises the following steps:

[0060] Silicon carbide is used as a substrate, the surface of the substrate is cleaned, graphene is dispersed in a solvent, and is evenly sprayed on the surface of the substrate, dried at 260-280° C., and a cross-linking agent is added to complete ceramicization to obtain the composite ceramic material.

[0061] Specifically, the solvent is polyethylene glycol and water, and the molar ratio of polyethylene glycol to water is 0.3:1.

[0062] Specifically, the cross-linking agent includes VTES.

[0063] Specifically, the crosslinking agent accounts for 2% of the mass of the substrate.

[0064] The method for preparing the high temperature resistant ablation coating material comprises the following steps:

[0065] Grind the composite ceramic material, carbon nanotubes and fillers, mix them at high speed,

[0066] Finally, polysilazane resin is added, mixed at a low speed, and heated for curing to obtain the high temperature resistant ablation coating material.

[0067] More specifically, the high-speed mixing has a rotation speed of 3000 r / min and a time of 1.5 h.

[0068] More specifically, the low-speed mixing has a rotation speed of 600 r / min and a time of 1 h.

[0069] More specifically, the heating and curing conditions are: oven treatment at 150°C for 2 hours, then heating to 170°C for 2 hours.

[0070] More specifically, the heating and curing further includes applying a pressure of 4 MPa at 150° C. and applying a pressure of 9 MPa at 170° C.

[0071] Example 3

[0072] A high-temperature ablation-resistant coating material comprises the following materials: 9 g of polysilazane resin, 80 g of composite ceramic material, 14 g of carbon nanotubes and 30 g of filler.

[0073] The polysilazane resin has a nitrogen mass fraction of 25% and a viscosity of 2200 mpa·s.

[0074] Specifically, the filler is titanium oxide.

[0075] Specifically, the carbon nanotube particle size is 25 nm.

[0076] Specifically, the method for preparing the composite ceramic material comprises the following steps:

[0077] Silicon carbide is used as a substrate, the surface of the substrate is cleaned, graphene is dispersed in a solvent, and is evenly sprayed on the surface of the substrate, dried at 260-280° C., and a cross-linking agent is added to complete ceramicization to obtain the composite ceramic material.

[0078] Specifically, the solvent is polyethylene glycol and water, and the molar ratio of polyethylene glycol to water is 0.25:1.

[0079] Specifically, the cross-linking agent includes VTES.

[0080] Specifically, the crosslinking agent accounts for 5% of the mass of the substrate.

[0081] The method for preparing the high temperature resistant ablation coating material comprises the following steps:

[0082] Grind the composite ceramic material, carbon nanotubes and fillers, mix them at high speed,

[0083] Finally, polysilazane resin is added, mixed at a low speed, and heated for curing to obtain the high temperature resistant ablation coating material.

[0084] More specifically, the high-speed mixing has a rotation speed of 2900 r / min and a time of 1.2 h.

[0085] More specifically, the low-speed mixing has a rotation speed of 500 r / min and a time of 0.8 h.

[0086] More specifically, the heat curing conditions are: oven treatment at 140°C for 1.5 hours, then heating to 165°C for 1.5 hours.

[0087] More specifically, the heating and curing further includes applying a pressure of 4 MPa at 140° C. and applying a pressure of 9 MPa at 165° C.

[0088] Example 4

[0089] A high-temperature ablation-resistant coating material comprises the following materials: 16 g of polysilazane resin, 90 g of composite ceramic material, 16 g of carbon nanotubes and 40 g of filler.

[0090] The nitrogen mass fraction of the polysilazane resin is 20%, and the viscosity is 2200 mpa·s.

[0091] Specifically, the filler is zirconium oxide.

[0092] Specifically, the particle size of the carbon nanotubes is 30 nm.

[0093] Specifically, the method for preparing the composite ceramic material comprises the following steps:

[0094] Silicon carbide is used as a substrate, the surface of the substrate is cleaned, graphene is dispersed in a solvent, and is evenly sprayed on the surface of the substrate, dried at 260-280° C., and a cross-linking agent is added to complete ceramicization to obtain the composite ceramic material.

[0095] Specifically, the cross-linking agent includes MTES.

[0096] Specifically, the crosslinking agent accounts for 4% of the mass of the substrate.

[0097] Specifically, the solvent is polyethylene glycol and water, and the molar ratio of polyethylene glycol to water is 0.2:1.

[0098] The method for preparing the high temperature resistant ablation coating material comprises the following steps:

[0099] Grind the composite ceramic material, carbon nanotubes and fillers, mix them at high speed,

[0100] Finally, polysilazane resin is added, mixed at a low speed, and heated for curing to obtain the high temperature resistant ablation coating material.

[0101] More specifically, the high-speed mixing has a rotation speed of 3000 r / min and a time of 1 h.

[0102] More specifically, the low-speed mixing has a rotation speed of 600 r / min and a time of 1 h.

[0103] More specifically, the heat curing conditions are: oven treatment at 140°C for 1.5 hours, then heating to 165°C for 1.5 hours.

[0104] More specifically, the heating and curing further includes applying a pressure of 4 MPa at 140° C. and applying a pressure of 9 MPa at 165° C.

[0105] Example 5

[0106] A high-temperature ablation-resistant coating material comprises the following materials: 9 g of polysilazane resin, 80 g of composite ceramic material, 14 g of carbon nanotubes and 30 g of filler.

[0107] The polysilazane resin has a nitrogen mass fraction of 35% and a viscosity of 3200 mpa·s.

[0108] Specifically, the filler is zirconium oxide.

[0109] Specifically, the particle size of the carbon nanotubes is 40 nm.

[0110] Specifically, the method for preparing the composite ceramic material comprises the following steps:

[0111] Silicon carbide is used as a substrate, the surface of the substrate is cleaned, graphene is dispersed in a solvent, and is evenly sprayed on the surface of the substrate, dried at 260-280° C., and a cross-linking agent is added to complete ceramicization to obtain the composite ceramic material.

[0112] Specifically, the solvent is polyethylene glycol and water, and the molar ratio of polyethylene glycol to water is 0.3:1.

[0113] Specifically, the cross-linking agent includes VTES.

[0114] Specifically, the crosslinking agent accounts for 3% of the mass of the substrate.

[0115] The method for preparing the high temperature resistant ablation coating material comprises the following steps:

[0116] Grind the composite ceramic material, carbon nanotubes and fillers, mix them at high speed,

[0117] Finally, polysilazane resin is added, mixed at a low speed, and heated for curing to obtain the high temperature resistant ablation coating material.

[0118] More specifically, the high-speed mixing has a rotation speed of 2800 r / min and a time of 1 h.

[0119] More specifically, the low-speed mixing has a rotation speed of 400 r / min and a time of 0.5 h.

[0120] More specifically, the heating and curing conditions are: oven treatment at 150°C for 2 hours, then heating to 170°C for 2 hours.

[0121] More specifically, the heat curing further includes applying a pressure of 4 MPa at 150° C. and applying a pressure of 9 MPa at 170° C.

[0122] Comparative Example 1

[0123] A high temperature ablation resistant coating material, which differs from Example 1 in that no composite ceramic material is added.

[0124] Comparative Example 2

[0125] A high temperature ablation resistant coating material, which differs from Example 2 in that no polysilazane resin is added.

[0126] Comparative Example 3

[0127] A high temperature ablation resistant coating material, which is different from Example 3 in that a composite ceramic material is not prepared according to the method thereof, but a composite material prepared from carbon black and silicon carbide.

[0128] Comparative Example 4

[0129] A high temperature resistant ablation coating material, which differs from Example 4 in that no carbon nanotubes are added.

[0130] Comparative Example 5

[0131] A high temperature ablation resistant coating material, which differs from Example 5 in that no filler is added.

[0132] Comparative Example 6

[0133] A high temperature resistant ablation coating material, which is different from Example 1 in that, in the preparation method of the high temperature resistant ablation coating material, the average speed after grinding is always 800r / min.

[0134] Comparative Example 7

[0135] A high temperature resistant ablation coating material, which differs from Example 1 in that the nitrogen mass fraction of the polysilazane resin is 40% and the viscosity is 4000 mpa·s.

[0136] Comparative Example 8

[0137] A high temperature resistant ablation coating material, which differs from Example 1 in that the solvent is PVA.

[0138] Comparative Example 9

[0139] A high temperature resistant ablation coating material, which differs from Example 1 in that the heating and curing further includes pressurizing to 3MPa at 130-150°C and pressurizing to 7MPa at 160-170°C.

[0140] The materials obtained from all the above embodiments and comparative examples were tested for physical and chemical properties, wherein the ablation performance was tested according to the standard of GJB323A-96; for the high-temperature carbon layer mechanical strength test, all the above materials were treated at 1600°C and nitrogen to cause pyrolysis and carbonization. 10 g of each material to be tested was taken and divided into 10 groups, and heat-treated in a muffle furnace. Each group of materials to be tested was placed in a muffle furnace, and nitrogen was introduced to reach a predetermined temperature at a heating rate of 10°C / min and maintained for 15 minutes. After cooling to room temperature with the furnace, relevant strength tests were performed to test the mechanical properties of carbonized materials.

[0141] Table 1 Carbonization performance of high temperature ablation resistant coating materials

[0142]

[0143] Table 2 Ablation resistance test of high temperature ablation resistant coating materials

[0144]

[0145] It can be seen from Tables 1 and 2 that without adding composite ceramic materials, polysilazane resins or carbon nanotubes and fillers, the final material ablation performance and mechanical strength are reduced to varying degrees; in addition, Comparative Example 8 also shows that the selection of solvents for dispersing graphene and silicon carbide also has a certain degree of influence on the formation of the graphene network and the efficiency of silicon carbide doping.

[0146] Most existing composite materials are carbon / phenolic resin composite materials and polyborosilazane for ceramic modification. However, phenolic resin will crack as the carbonization temperature increases, resulting in an increase in internal porosity, which increases the amount of polyborosilazane added and greatly affects the dispersibility of the composite material. This in turn affects the high temperature resistance and ablation resistance of the final material.

[0147] In summary, the present invention provides a high-temperature ablation-resistant coating material, which is obtained by introducing a composite ceramic material of silicon carbide and graphene and polysilazane, adding zirconium oxide, carbon nanotubes, etc. for blending, so as to obtain a high-temperature ablation-resistant coating material with good dispersibility and excellent mechanical properties.

[0148] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high temperature ablation resistant coating material, characterized in that: The invention is composed of the following materials in parts by weight: 3-16 parts of polysilazane resin, 75-90 parts of composite ceramic material, 11-16 parts of carbon nanotubes and 22-40 parts of filler; the nitrogen mass fraction of the polysilazane resin is 8%-35%, and the viscosity is 500-3200 mPa·s; the filler is one of zirconium oxide, zirconium boride and titanium oxide; The preparation method of the composite ceramic material comprises the following steps: Silicon carbide is used as a substrate, the surface of the substrate is cleaned, graphene is dispersed in a solvent, and is evenly sprayed on the surface of the substrate, dried at 260-280° C., and a cross-linking agent is added to complete ceramicization to obtain the composite ceramic material; The cross-linking agent includes ethyltriethoxysilane or methyltriethoxysilane, and the cross-linking agent accounts for 2-5% of the mass of the substrate. The solvent is polyethylene glycol and water, and the molar ratio of polyethylene glycol to water is 0.2-0.3:

1.

2. The high temperature ablation resistant coating material according to claim 1, characterized in that: The particle size of the carbon nanotubes is 20-40 nm.

3. The method for preparing a high temperature ablation resistant coating material according to any one of claims 1 to 2, characterized in that: The steps include: Grind the composite ceramic material, carbon nanotubes and fillers, mix them at high speed, Finally, polysilazane resin is added, mixed at a low speed, and heated for curing to obtain the high temperature resistant ablation coating material.

4. The method for preparing a high temperature ablation resistant coating material according to claim 3, characterized in that: The high-speed mixing has a rotation speed of 2800-3000 r / min and a time of 1-1.5 h.

5. The method for preparing a high temperature ablation resistant coating material according to claim 3, characterized in that: The low-speed mixing has a rotation speed of 400-600 r / min and a time of 0.5-1 h.

6. The method for preparing a high temperature ablation resistant coating material according to claim 3, characterized in that: The heating and curing conditions are: oven treatment at 130-150° C. for 1-2 hours, and then heating to 160-170° C. for 1-2 hours.

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