Zirconium phosphate modified ceramic fiber thermal insulation material and preparation method thereof

Abstract

The invention discloses a thermal insulation material and a preparation method thereof, and the thermal insulation material is specifically a zirconium phosphate modified ceramic fiber thermal insulation material and is suitable for a working environment needing thermal insulation and pressure bearing. The preparation method of the zirconium phosphate modified ceramic fiber thermal insulation material comprises the steps of preparing a zirconium phosphate base material, preparing a zirconium phosphate dispersion liquid, preparing a dispersion solvent, preparing a ceramic fiber material suspension and preparing the zirconium phosphate modified ceramic fiber thermal insulation material which are sequentially carried out. The thermal insulation material prepared by the method is short in time consumption and low in process cost. The porosity of the existing commercially available ceramic fiber material can be directionally regulated and controlled by adjusting the concentration and dispersity of the modifier (zirconium phosphate), composite thermal insulation materials with different supporting strengths and volume densities can be prepared as required, and the defect that a conventional ceramic fiber thermal insulation material is insufficient in supporting performance is overcome.

Description

Technical Field

[0001] The invention relates to a zirconium phosphate-modified ceramic fiber thermal insulation material and a preparation method thereof, belonging to the technical field of thermal insulation materials. Background Art

[0002] In the field of helicopter engine thermal protection, the thermal insulation layer is usually attached to the inner surface of the engine compartment fairing. It plays a role of thermal insulation when the engine is working. When the engine is maintained, the thermal insulation layer can be used as a support platform for maintenance personnel to stand and perform maintenance work. Therefore, the core of the thermal insulation layer - the thermal insulation material, should have good thermal insulation performance and supporting strength. Traditional thermal insulation materials usually use non-metallic fiber felt or porous aerogel. Among them, non-metallic fiber felt is very easy to be compressed due to the flexible texture of the fiber filaments and the large number of pores between the fiber filaments. The thermal insulation layer processed with non-metallic fiber felt has poor support and is prone to forming plastic potholes or surface defects where maintenance personnel step on it; and the porous structure of aerogel particles has no adhesion between them, and is prone to falling off during use.

[0003] To overcome these drawbacks, the most straightforward approach is to use a rigid metal skin of a defined thickness as a "wrapping frame" for the insulation material, sandwiching it within the insulation. While the combination of insulation and a metal skin of defined thickness achieves high thermal resistance and high support strength, the increased thickness of the metal skin leads to a dramatic increase in the weight of the insulation layer, negatively impacting the aircraft's load capacity. Designing new performance based on material properties requires a series of modifications and adjustments to the synthesis and preparation processes, resulting in significant investment costs. To achieve both superior insulation performance and support strength while maintaining manageable weight at a low cost, the present invention is proposed. Summary of the Invention

[0004] The present invention aims to provide a zirconium phosphate-modified ceramic fiber thermal insulation material and a preparation method thereof. The existing commercially available ceramic fiber thermal insulation material is modified using micro-nano zirconium phosphate flakes with good mechanical properties and thermal stability, thereby enhancing the supporting strength of the original thermal insulation material and providing a high thermal resistance, high supporting strength, and low-cost thermal insulation material for the thermal protection of my country's helicopter engines.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A thermal insulation material comprising:

[0007] Ceramic fiber as a matrix;

[0008] Zirconium phosphate added to ceramic fibers as a modifying material.

[0009] The method for preparing the thermal insulation material as described above comprises the following steps:

[0010] S1, preparing a zirconium phosphate substrate, mixing zirconium phosphate solid and hydrophobic silica in a mass ratio of (20-30):1 and grinding and pulverizing to obtain a zirconium phosphate substrate;

[0011] S2, preparing a zirconium phosphate dispersion, taking the zirconium phosphate base material in S1 and adding it to the formamide aqueous solution, and uniformly stirring to obtain a zirconium phosphate dispersion;

[0012] S3, preparing a dispersion solvent by adding one or two of polyvinyl pyrrolidone, polyethylene glycol, and sodium lauryl sulfate to deionized water, and stirring and heating in a water bath to obtain a dispersion solvent;

[0013] S4, preparing a ceramic fiber material suspension, taking a commercially available ceramic fiber thermal insulation material and baking it at high temperature, immersing the baked ceramic fiber thermal insulation material in the dispersed solvent prepared in S3, and ultrasonically treating it to obtain a ceramic fiber material suspension;

[0014] S5, prepare zirconium phosphate modified ceramic fiber thermal insulation material, mix the zirconium phosphate dispersion in S2 and the ceramic fiber material suspension in S4 and stir to obtain a mixed suspension, filter the mixed suspension to obtain a modified ceramic fiber thermal insulation material precursor, press and shape the modified ceramic fiber thermal insulation material precursor in sequence, and then calcine the shaped modified ceramic fiber thermal insulation material precursor to finally obtain zirconium phosphate modified ceramic fiber thermal insulation material.

[0015] As a solution: the zirconium phosphate solid in S1 is prepared by the following steps:

[0016] S11, preparing an oxalic acid solution and heating it in an oil bath at a temperature not exceeding 70°C;

[0017] S12, adding zirconium oxychloride octahydrate to the oxalic acid solution prepared in S11 and stirring evenly, then adding concentrated phosphoric acid dropwise, controlling the molar ratio of concentrated phosphoric acid to zirconium oxychloride octahydrate to be not less than 4:1;

[0018] S13, raising the oil bath temperature and maintaining stirring for 18 to 24 hours, with the reaction temperature not lower than 100° C., and condensation reflux is required during the reaction;

[0019] S14, after the reaction is completed, the mixture is repeatedly washed with deionized water and centrifuged until the filtrate is neutral, and the solid reactant is taken out and dried in an oven at 60° C. to obtain zirconium phosphate solid.

[0020] As a solution, in S1, zirconium phosphate solid and hydrophobic silica are mixed in a mass ratio of (20-30):1 and then placed in a planetary ball mill for grinding and pulverization.

[0021] As a solution, in S2, a cantilever stirrer is used to uniformly stir the zirconium phosphate dispersion, and the stirring time is 30 to 60 minutes.

[0022] As a solution, in S3, when the dispersion solvent is obtained by stirring and heating in a water bath, the stirring time is 30 to 60 minutes and the heating temperature is 50 to 60°C.

[0023] As a solution, in S4, commercially available ceramic fiber insulation material is placed in a muffle furnace for high-temperature baking at a temperature of 300 to 400° C. for a time of 1 to 3 hours.

[0024] As a solution, in S4, ultrasonic treatment is performed for 30 to 60 minutes to obtain a ceramic fiber material suspension, the ultrasonic single working time is 8 seconds, and the working interval is 10 seconds.

[0025] As a solution, in S5:

[0026] The zirconium phosphate dispersion in S2 and the ceramic fiber material suspension in S4 are mixed and stirred for 1 to 2 hours using a cantilever stirrer at a stirring speed of 1000 to 2000 rpm to obtain a mixed suspension;

[0027] The mixed suspension is filtered by a vacuum filter to obtain a modified ceramic fiber thermal insulation material precursor;

[0028] The modified ceramic fiber thermal insulation material precursor is placed in a stainless steel mold and pressed and shaped in sequence;

[0029] The shaped modified ceramic fiber thermal insulation material precursor is placed in a muffle furnace for calcination at a temperature of 700 to 1000° C. for 5 to 8 hours, thereby finally obtaining a zirconium phosphate modified ceramic fiber thermal insulation material.

[0030] Application of the aforementioned thermal insulation materials in helicopter engine thermal protection.

[0031] Compared with the prior art, the present invention has the following characteristics:

[0032] (1) The present invention introduces a zirconium phosphate substrate with a stable structure, high temperature resistance and high mechanical properties into the gaps between existing ceramic fiber filaments, thereby enhancing the supporting strength of the ceramic fiber thermal insulation material and compensating for the shortcomings of the conventional ceramic fiber thermal insulation material in terms of insufficient support.

[0033] (2) Zirconium phosphate itself has high thermal stability, with a decomposition temperature of over 1400°C, and the decomposition product is still a high-temperature resistant, low-thermal-resistance zirconium oxide ceramic. Using zirconium phosphate as a modified material will not reduce the thermal conductivity of the original ceramic fiber material. In addition, zirconium phosphate also has a flame retardant and smoke suppression effect on organic materials such as resins under high temperature conditions; (3) The modification method proposed in the present invention can directionally control the porosity of existing commercially available ceramic fiber materials by adjusting the concentration and dispersion of the modifier (zirconium phosphate), and composite thermal insulation materials with different support strengths and volume densities can be prepared as needed;

[0034] (4) For some special usage scenarios, the modification method proposed in the present invention can use a mold to process the required shape of the thermal insulation material during the crimping and shaping process of the modified ceramic fiber thermal insulation material, and solidify the shape after secondary high-temperature sintering;

[0035] (5) Compared with redesigning and synthesizing ceramic fiber filaments, the modification method proposed in the present invention is time-consuming and has significantly reduced process costs:

[0036] (6) The preparation method of the present invention can be used to obtain micro-nano-scale, flaky zirconium phosphate. Compared with other shapes, the flaky zirconium phosphate has better dispersibility in formamide solution and is easier to be composited with ceramic fibers later. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a scanning electron microscope image of the zirconium phosphate substrate;

[0038] Figure 2 This is a scanning electron microscope image of zirconium phosphate modified ceramic fiber insulation material;

[0039] Figure 3 It is a flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described below with reference to the accompanying drawings and specific embodiments. However, it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various modifications, substitutions and changes made according to common technical knowledge and customary means in the field are included in the scope of the present invention.

[0041] See Figure 3 , is a method for preparing a zirconium phosphate-modified ceramic fiber thermal insulation material of the present invention, comprising the following steps:

[0042] Step 1. Preparation of zirconium phosphate substrate:

[0043] a) Prepare oxalic acid solution of a certain concentration and heat it in an oil bath at a temperature not exceeding 70°C;

[0044] b) adding a certain amount of zirconium oxychloride octahydrate to the oxalic acid solution and stirring uniformly, and then adding concentrated phosphoric acid dropwise, controlling the molar ratio of concentrated phosphoric acid to zirconium oxychloride octahydrate to be not less than 4:1;

[0045] c) Raise the oil bath temperature and maintain stirring for 18 to 24 hours. The reaction temperature should not be lower than 100°C. Condensation reflux should be performed during the reaction.

[0046] d) After the reaction is completed, the mixture is repeatedly washed with deionized water and centrifuged until the filtrate is neutral, and the solid reactant is taken out and dried in an oven at 60° C. to obtain zirconium phosphate solid;

[0047] e) zirconium phosphate solid and hydrophobic silica are mixed in a mass ratio of (20-30):1 and placed in a planetary ball mill for grinding to obtain a zirconium phosphate substrate.

[0048] Step 2. Prepare zirconium phosphate dispersion:

[0049] A certain amount of zirconium phosphate substrate is added to a formamide aqueous solution, and the solution is uniformly stirred using a cantilever stirrer for 30 to 60 minutes to obtain a zirconium phosphate dispersion.

[0050] Step 3. Prepare the dispersion solvent:

[0051] A certain amount of one or two of polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), and sodium dodecyl sulfate (SDS) are added to deionized water, and stirred and heated in a water bath to obtain a dispersion solvent. The stirring time is 30 to 60 minutes, and the heating temperature is 50 to 60°C.

[0052] Step 4. Preparation of ceramic fiber material suspension:

[0053] a) taking a certain amount of commercially available ceramic fiber insulation material (e.g., aluminum silicate ceramic fiber blanket) and placing it in a muffle furnace for high-temperature baking at a temperature of 300-400° C. for 1-3 hours;

[0054] b) Immerse the baked ceramic fiber insulation material in a dispersing solvent and ultrasonically treat it for 30 to 60 minutes to obtain a ceramic fiber material suspension, with a single ultrasonic working time of 8 seconds and a working interval of 10 seconds. Step 5. Prepare zirconium phosphate modified ceramic fiber insulation material:

[0055] a) mixing the zirconium phosphate dispersion and the ceramic fiber material suspension in a certain volume ratio, and then stirring with a cantilever stirrer for 1 to 2 hours to obtain a mixed suspension at a stirring speed of 1000 to 2000 rpm.

[0056] b) filtering the mixed suspension using a vacuum filter to obtain a modified ceramic fiber thermal insulation material precursor;

[0057] c) placing the modified ceramic fiber thermal insulation material precursor into a stainless steel mold for crimping and shaping;

[0058] d) placing the shaped modified ceramic fiber thermal insulation material precursor into a muffle furnace and calcining it to obtain a zirconium phosphate modified ceramic fiber thermal insulation material, the calcination temperature is 700-1000°C, the calcination time is 5-

[0059] 8h.

[0060] Examples (the present invention has no particular limitation on the sources of all raw materials, and any commercially available raw materials may be used):

[0061] a) Prepare 500 ml of 0.01 mol / L oxalic acid solution and heat in an oil bath at 50°C;

[0062] b) 4.8 g of zirconium oxychloride octahydrate was added to the oxalic acid solution in step a) and stirred evenly, followed by dropwise addition of 40 ml of 85% concentrated phosphoric acid.

[0063] c) Raise the oil bath temperature and keep stirring for 24 hours at a reaction temperature of 120°C. Condensation and reflux are required during the reaction.

[0064] d) After the reaction is completed, the mixture is repeatedly washed with deionized water and centrifuged until the filtrate is neutral, and the solid reactant is taken out and dried in an oven at 60° C. to obtain zirconium phosphate solid;

[0065] e) zirconium phosphate solid and hydrophobic silica were mixed in a mass ratio of 25:1 and placed in a planetary ball mill for grinding to obtain a zirconium phosphate substrate. The micromorphology of the obtained zirconium phosphate substrate is shown in FIG. Figure 1 ;

[0066] f) 4 g of zirconium phosphate substrate was added to the formamide aqueous solution and stirred evenly with a cantilever stirrer to obtain a zirconium phosphate dispersion for 60 min.

[0067] g) Prepare 1000 ml of 1 wt% PVP solution and stir in a water bath for 30 min;

[0068] h) 45 g of a commercially available ceramic fiber insulation material was placed in a muffle furnace and baked at 400° C. for 2 h.

[0069] i) immersing the baked ceramic fiber insulation material in the PVP solution and ultrasonically treating it for 50 minutes to obtain a ceramic fiber material suspension, wherein the ultrasonic single working time is 8 seconds and the working interval is 10 seconds;

[0070] j) mixing the zirconium phosphate dispersion and the ceramic fiber material suspension in a volume ratio of 1:2, and then stirring for 1 hour using a cantilever stirrer at a stirring speed of 1000 rpm to obtain a mixed suspension;

[0071] k) filtering the mixed suspension using a vacuum filter to obtain a modified ceramic fiber thermal insulation material precursor;

[0072] 1) placing the modified ceramic fiber thermal insulation material precursor into a stainless steel mold for crimping and shaping;

[0073] m) The shaped modified ceramic fiber thermal insulation material precursor was placed in a muffle furnace and calcined to obtain a zirconium phosphate modified ceramic fiber thermal insulation material. The calcination temperature was 900°C and the calcination time was 8 hours. The scanning electron microscope image of the obtained zirconium phosphate modified ceramic fiber thermal insulation material was shown in FIG. Figure 2 .

[0074] Those skilled in the art will be able to make various adjustments to this application based on actual circumstances. The general principles defined in this application may be implemented in other implementations without departing from the scope of the disclosure. Therefore, this application is not limited to the specific embodiments shown, but is intended to conform to the broadest scope consistent with the principles and features set forth in the claims of this application.

Claims

1. A thermal insulation material, characterized in that: include: Ceramic fiber as a matrix; Zirconium phosphate added to ceramic fibers as a modifying material.

2. The method for preparing the thermal insulation material according to claim 1, wherein: The following steps are involved: S1, preparing a zirconium phosphate substrate, mixing zirconium phosphate solid and hydrophobic silica in a mass ratio of (20-30):1 and grinding and pulverizing to obtain a zirconium phosphate substrate; S2, preparing a zirconium phosphate dispersion, taking the zirconium phosphate base material in S1 and adding it to the formamide aqueous solution, and uniformly stirring to obtain a zirconium phosphate dispersion; S3, preparing a dispersion solvent by adding one or two of polyvinyl pyrrolidone, polyethylene glycol, and sodium lauryl sulfate to deionized water, and stirring and heating in a water bath to obtain a dispersion solvent; S4, preparing a ceramic fiber material suspension, taking a commercially available ceramic fiber thermal insulation material and baking it at high temperature, immersing the baked ceramic fiber thermal insulation material in the dispersed solvent prepared in S3, and ultrasonically treating it to obtain a ceramic fiber material suspension; S5, prepare zirconium phosphate modified ceramic fiber thermal insulation material, mix the zirconium phosphate dispersion in S2 and the ceramic fiber material suspension in S4 and stir to obtain a mixed suspension, filter the mixed suspension to obtain a modified ceramic fiber thermal insulation material precursor, press and shape the modified ceramic fiber thermal insulation material precursor in sequence, and then calcine the shaped modified ceramic fiber thermal insulation material precursor to finally obtain zirconium phosphate modified ceramic fiber thermal insulation material.

3. The method for preparing the thermal insulation material according to claim 2, characterized in that: The zirconium phosphate solid in S1 is prepared by the following steps: S11, preparing an oxalic acid solution and heating it in an oil bath at a temperature not exceeding 70°C; S12, adding zirconium oxychloride octahydrate to the oxalic acid solution prepared in S11 and stirring evenly, then adding concentrated phosphoric acid dropwise, controlling the molar ratio of concentrated phosphoric acid to zirconium oxychloride octahydrate to be not less than 4:1; S13, raising the oil bath temperature and maintaining stirring for 18 to 24 hours, with the reaction temperature not lower than 100° C., and condensation reflux is required during the reaction; S14, after the reaction is completed, the mixture is repeatedly washed with deionized water and centrifuged until the filtrate is neutral, and the solid reactant is taken out and dried in an oven at 60° C. to obtain zirconium phosphate solid.

4. The method for preparing the thermal insulation material according to claim 2, characterized in that: In the S1, zirconium phosphate solid and hydrophobic silica are mixed in a mass ratio of (20-30):1 and then placed in a planetary ball mill for grinding and pulverization.

5. The method for preparing the thermal insulation material according to claim 2, characterized in that: In S2, a cantilever stirrer is used to uniformly stir the zirconium phosphate dispersion, and the stirring time is 30 to 60 minutes.

6. The method for preparing the thermal insulation material according to claim 2, characterized in that: In the above S3, when the dispersion solvent is obtained by stirring and heating in a water bath, the stirring time is 30 to 60 minutes and the heating temperature is 50 to 60°C.

7. The method for preparing the thermal insulation material according to claim 2, characterized in that: In the step S4, commercially available ceramic fiber insulation material is placed in a muffle furnace for high-temperature baking at a temperature of 300 to 400° C. for a time of 1 to 3 hours.

8. The method for preparing the thermal insulation material according to claim 2, characterized in that: In the above S4, ultrasonic treatment is performed for 30 to 60 minutes to obtain a ceramic fiber material suspension, the ultrasonic single working time is 8 seconds, and the working interval is 10 seconds.

9. The method for preparing the thermal insulation material according to claim 2, characterized in that: In said S5: The zirconium phosphate dispersion in S2 and the ceramic fiber material suspension in S4 are mixed and stirred for 1 to 2 hours using a cantilever stirrer at a stirring speed of 1000 to 2000 rpm to obtain a mixed suspension; The mixed suspension is filtered by a vacuum filter to obtain a modified ceramic fiber thermal insulation material precursor; The modified ceramic fiber thermal insulation material precursor is placed in a stainless steel mold and pressed and shaped in sequence; The shaped modified ceramic fiber thermal insulation material precursor is placed in a muffle furnace for calcination at a temperature of 700 to 1000° C. for 5 to 8 hours, thereby finally obtaining a zirconium phosphate modified ceramic fiber thermal insulation material.

10. Use of the thermal insulation material according to claim 1 in thermal protection of helicopter engines.

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