Preparation method of rare earth aluminum nitride solid solution

Abstract

The invention discloses a preparation method of a rare earth aluminum nitride solid solution and belongs to the technical field of high-heat-conductivity-coefficient materials. Aluminum nitride is modified through aluminum dihydrogen phosphate ball milling, then the modified aluminum nitride and cerium salt are stirred to react in a phosphoric acid solution to obtain a rare earth aluminum nitride aqueous solution, and the rare earth aluminum nitride solid solution powder with high hydrolysis resistance and good heat-conducting property is prepared through filtering and drying. The heat conductivity coefficient of the rare earth aluminum nitride prepared by the method disclosed by the invention is 0.201 W / (m.K)-0.355 W / (m.K), and the diffraction peak of the crystal face (101) of the aluminum nitride migrates to a low angle by 0.02-0.1 degree.

Description

Technical Field

[0001] The invention belongs to the technical field of high thermal conductivity material preparation, and mainly relates to a method for preparing rare earth aluminum nitride solid solution powder. Background Art

[0002] With the global "greenhouse effect" becoming increasingly severe and the emergence of extreme climate, summer temperatures continue to rise, and the market demand for cool fabrics is rapidly increasing. [1] Under the same temperature, the body temperature when exercising in clothing made of a certain cool fabric is 1.27℃ lower than when wearing ordinary moisture-wicking fabric.

[0003] The development of cool fabrics can be divided into two categories in principle: one is to improve the thermal conductivity of textiles and enhance the ability of textiles to dissipate heat to the environment; the other is to improve the hygroscopicity and water conductivity of textiles so that human sweat can be quickly absorbed and discharged by clothing, and the purpose of heat dissipation can be achieved through sweat evaporation. Fabrics usually have low thermal conductivity. The thermal conductivity of cotton, wool and polyester fibers is only 0.07W / (m·K), 0.05W / (m·K) and 0.14W / (m·K) respectively. If a cool powder with a higher thermal conductivity is added to the fiber, the thermal conductivity of the fiber can be increased, so that the fabric can quickly conduct heat energy at the moment of contact with the skin surface, making the clothing feel instantly cool.

[0004] Commonly used high thermal conductivity powders include mica, jade, boron nitride (BN), aluminum nitride (AlN), etc.: Using a cooling finishing agent containing high thermal conductivity materials (such as boron nitride powder, aluminum nitride powder, silicon nitride powder) to treat the fabric can quickly conduct away the heat caused by skin contact and achieve a cooling effect on the fabric. [2]

[0005] The common cooling fibers on the market usually achieve a cooling effect by adding jade powder or mica powder. For example, by adding boron nitride powder to polyvinyl alcohol slices, boron nitride / polyvinyl alcohol composite fibers are produced. The thermal conductivity of the fabric produced by adding boron nitride powder to polyvinyl alcohol slices is 55% higher than that of commercial cotton fabrics. [3] ; Mica and AlN powders were used as cooling modifiers, and the two were melt-blended by a twin-screw extruder to prepare modified HDPE slices with better thermal conductivity. The modified HDPE slices were used as the skin layer and the PA6 slices were used as the core layer. The modified HDPE / PA6 skin-core composite cooling fiber with both contact cooling and hygroscopic properties was prepared by the skin-core composite spinning method. The contact cooling coefficient reached 0.29 J / (cm 2 ·s) [4] Boron nitride and shell powder are selected as functional powders to improve the thermal conductivity of PLA. After adding high thermal conductivity inorganic powder, the cool touch value of the fabric is significantly improved, and it has cool touch performance.[5] Adding natural mineral nano-scale jade powder, high thermal conductivity aluminum nitride, and mint essential oil microcapsules into PLA fibers, the contact coolness values ​​(q max ) have been significantly improved, and both have good cooling effects. [6] However, the thermal conductivity of the powder obtained by the above method is not ideal, and aluminum nitride is a material with high thermal conductivity, which is an ideal material for improving the thermal conductivity of fibers. However, AlN powder has the problem of easy hydrolysis. AlN powder will slowly react in the air to produce aluminum hydroxide compounds and ammonia. If it directly encounters water, the hydrolysis of AlN powder will be more serious. The hydrolysis of AlN will greatly affect its thermal conductivity.

[0006] Rare earths are called "industrial vitamins" because of their special arrangement of electrons outside the nucleus and high chemical activity. A large number of studies have confirmed that rare earth elements can improve the comprehensive properties of materials. As one of the rare earth elements with high cost performance, the addition of Ce has a certain effect on the thermal conductivity of the alloy, but its effect on the thermal conductivity of AlN powder has not been reported.

[0007] The present invention adopts Al(H 2 PO 4 ) 3 , H 3 PO 4 And cerium salt is used to modify AlN to improve its hydrolysis resistance and thermal conductivity.

[0008] Literature [1] Ren Xiaogang, Qi Lu. Research status and application of cool fibers [J]. Synthetic Fiber Industry, 2010, 33(1): 39-41.

[0009] Reference [2] Cui Mengting, Zhang Hongnan, Lü Zhijia, et al. Research on the cooling function of pure cotton textiles [J]. Cotton Textile Technology, 2023, 51(4): 1-5.

[0010] Literature [3] GAO T, YANG Z, CHEN C, et al. Three-Dimensional Printed ThermalRegulation Textiles. [J / OL]. ACS Nano, 2017, 11(11): 11513-11520. DOI: 10.1021 / acsnano.7b06295.

[0011] Reference [4] Huang Yikun, Weng Ming, Chen Hongwei, et al. Preparation and properties of modified polyethylene chips for cooling fibers [J]. Journal of Zhejiang Sci-Tech University (Natural Science Edition), 2023, 49(1): 1-8.

[0012] Reference [5] Ding Jiuyang. Preparation and performance research of cool polylactic acid fiber and fabric [D / OL]. Donghua University, 2024 [2024-10-28].

[0013] https: / / kns.cnki.net / KCMS / detail / detail.aspx?dbcode=CMFD&dbname=CMFD202401&filename=1023587466.nh.DOI:10.27012 / d.cnki.gdhuu.2023.000420.

[0014] Reference [6] Wei Yanhong, Yang Jialong, Xia Yifeng, et al. Preparation and performance research of cool polylactic acid fiber [J]. Cotton Textile Technology, 2024: 1-6. Summary of the invention

[0015] The purpose of the present invention is to provide a method for preparing rare earth aluminum nitride high thermal conductivity powder, by adding phosphoric acid and cerium salt after ball milling modification of aluminum dihydrogen phosphate, to prepare rare earth aluminum nitride solid solution powder with strong hydrolysis resistance and good thermal conductivity.

[0016] To achieve the above object, the present invention adopts the following technical solutions:

[0017] A method for preparing a rare earth aluminum nitride solid solution comprises the following steps:

[0018] 1. Mix the modifier with aluminum nitride, the amount of the modifier added is 2.5% to 8% of the mass of aluminum nitride; the modifier is Al(H 2 PO 4 ) 3 .

[0019] 2. Mix aluminum nitride and modifier and place in a ball mill, add anhydrous ethanol to the ball mill so that the total solid content of the mixture is 25%, and ball mill for 2 hours;

[0020] 3. After ball milling, filter and dry, add the obtained modified aluminum nitride powder into a deionized water solution mixed with phosphoric acid and cerium salt, stir for 30 minutes, and obtain a rare earth aluminum nitride aqueous solution. The amount of phosphoric acid added is 3.98%-11.9% of the mass of the modified aluminum nitride, and the amount of cerium salt added is 10%-30% of the mass of the modified aluminum nitride. The cerium salt is cerium chloride or cerium nitrate.

[0021] 4. After stirring, filter and dry to obtain the product rare earth aluminum nitride solid solution powder.

[0022] The thermal conductivity of the rare earth aluminum nitride solid solution powder is 0.201W / (m·K) to 0.355W / (m·K); the (101) crystal plane diffraction peak of aluminum nitride in the rare earth aluminum nitride solid solution powder product migrates to a low angle by 0.02° to 0.1°.

[0023] Beneficial effects of the present invention:

[0024] (1) During the addition of cerium, the diffraction peak x of the (101) crystal plane of aluminum nitride powder shifted to the left by 0.02° to 0.1°, and the spacing between the aluminum nitride crystal planes increased, indicating that Ce atoms dissolved into the aluminum nitride lattice and that the cerium salt and aluminum nitride formed a solid solution.

[0025] (2) The formation of cerium-aluminum nitride solid solution improves the thermal conductivity of aluminum nitride powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 XRD diagram of rare earth aluminum nitride solid solution powder of Example 1 of the present invention;

[0027] Figure 2 XRD pattern of rare earth aluminum nitride solid solution powder of Example 2 of the present invention;

[0028] Figure 3 XRD pattern of rare earth aluminum nitride solid solution powder of Example 3 of the present invention;

[0029] Figure 4 SEM image of the rare earth aluminum nitride solid solution powder in Example 3; wherein (a) is an electron image of the rare earth aluminum nitride solid solution powder, (b) is a distribution diagram of each element, (c) is a distribution diagram of the N element, (d) is a distribution diagram of the O element, (e) is a distribution diagram of the Al element, and (f) is a distribution diagram of the Ce element;

[0030] Figure 5 Infrared spectra of rare earth aluminum nitride solid solution powders of various embodiments of the present invention. DETAILED DESCRIPTION

[0031] The following is a further explanation of the invention content of the present invention through specific embodiments in combination with the accompanying drawings, but it should not be understood that the scope of the present invention is limited to the following examples. According to the inventive ideas and full content of the present invention, the various technical features in the following examples can be appropriately combined / replaced / adjusted / modified, etc., which is obvious to those skilled in the art and still falls within the scope of protection of the present invention.

[0032] The ball milling in the embodiment of the present invention adopts a planetary ball mill.

[0033] The stirring in the embodiment of the present invention adopts a constant temperature magnetic stirrer.

[0034] The water used in the embodiments of the present invention is deionized water, and the compounds used are all commercially available analytical reagents.

[0035] Example 1

[0036] This embodiment prepares a rare earth aluminum nitride solid solution, comprising the following steps:

[0037] Step 1. Weigh 15g of aluminum nitride powder and mix aluminum nitride and Al(H 2 PO 4 ) 3 Mixing is performed to obtain a mixture.

[0038] Step 2. Place the mixture in a ball mill, add anhydrous ethanol at a solid content of 25%, and ball mill for 2 hours.

[0039] Step 3. After ball milling, filter and dry, weigh 10g of the filtered modified aluminum nitride powder; add the modified aluminum nitride powder to a mixture containing cerium chloride (10% by mass of the modified aluminum nitride) and H 3 PO 4 A 10% solid content aqueous solution was prepared in a deionized water solution and stirred for 30 minutes.

[0040] Step 4. After stirring, filter and dry to obtain a rare earth aluminum nitride solid solution powder product. The thermal conductivity of the product is 0.201 W / (m·K). The XRD diagram is as follows: Figure 1 As shown in FIG. 1 , XRD test of rare earth aluminum nitride solid solution powder product shows that the (101) crystal plane diffraction peak shifts to a lower angle by 0.02°. The hydrolysis degree is only 10.5%, and its infrared spectrum is as follows: Figure 5 shown.

[0041] Example 2

[0042] This embodiment prepares a rare earth aluminum nitride solid solution, comprising the following steps:

[0043] Step 1. Weigh 15 g of aluminum nitride powder and mix aluminum nitride and Al(H 2 PO 4 ) 3 Mixing is performed to obtain a mixture.

[0044] Step 2. Place the mixture in a ball mill, add anhydrous ethanol at a solid content of 25%, and ball mill for 2 hours.

[0045] Step 3. After ball milling, filter and dry, weigh 10g of the filtered modified aluminum nitride powder; add the modified aluminum nitride powder to a mixture containing 20% ​​cerium chloride by mass of the modified aluminum nitride and the same molar amount of H3 PO 4 A 10% solid content aqueous solution was prepared in a deionized water solution and stirred for 30 minutes.

[0046] Step 4. After stirring, filter to obtain rare earth aluminum nitride solid solution powder product. The thermal conductivity of the product is 0.269W / (m·K). Its XRD diagram is as follows: Figure 2 As shown in FIG. 1 , XRD test of rare earth aluminum nitride solid solution powder product shows that the (101) crystal plane diffraction peak shifts to a lower angle by 0.05°. After testing, its hydrolysis degree is only 11.2%, and its infrared spectrum is as follows: Figure 5 shown.

[0047] Example 3

[0048] This embodiment prepares a rare earth aluminum nitride solid solution, comprising the following steps:

[0049] Step 1. Weigh 15g of aluminum nitride powder and mix aluminum nitride and Al(H 2 PO 4 ) 3 Mixing is performed to obtain a mixture.

[0050] Step 2. Place the mixture in a ball mill, add anhydrous ethanol at a solid content of 25%, and ball mill for 2 hours.

[0051] Step 3. After ball milling, filter and dry, weigh 10g of the filtered modified aluminum nitride powder; add the modified aluminum nitride powder to a mixture containing 30% cerium chloride by mass of the modified aluminum nitride and the same molar amount of H 3 PO 4 A 10% solid content aqueous solution was prepared in a deionized water solution and stirred for 30 minutes.

[0052] Step 4. After stirring, filter to obtain rare earth aluminum nitride solid solution powder product. The thermal conductivity of the product is 0.355 W / (m·K). Its XRD diagram is as follows: Figure 3 As shown in Figure 1, the XRD test of the rare earth aluminum nitride solid solution powder product shows that the (101) crystal plane diffraction peak shifts to a lower angle by 0.1°. Figure 4 As shown in the figure, each component is evenly distributed. After testing, its hydrolysis degree is only 8.5%, and its infrared spectrum is as follows Figure 5 shown.

Claims

1. A method for preparing a rare earth aluminum nitride solid solution, characterized in that: The following steps are involved: Step 1. mixing a modifier with aluminum nitride to obtain a mixture; Step 2. placing the mixture in a ball mill, adding anhydrous ethanol thereto and then ball milling; Step 3. After ball milling, the modified aluminum nitride powder is filtered and dried, and the obtained modified aluminum nitride powder is added to a deionized water solution mixed with phosphoric acid and cerium salt, and stirred to obtain a rare earth aluminum nitride aqueous solution; Step 4: After stirring, filter and dry to obtain the product rare earth aluminum nitride solid solution powder.

2. The method for preparing a rare earth aluminum nitride solid solution according to claim 1, characterized in that: In step 1, the amount of the modifier added is 2.5% to 8% of the mass of aluminum nitride.

3. The method for preparing a rare earth aluminum nitride solid solution according to claim 1, characterized in that: In step 1, the modifier is Al(H2PO4)3.

4. The method for preparing a rare earth aluminum nitride solid solution according to claim 1, characterized in that: In step 2, after adding ethanol, the total solid content of the mixture is 25%; The ball milling time was 2 h.

5. The method for preparing a rare earth aluminum nitride solid solution according to claim 1, characterized in that: In step 3, the stirring time is 30 min.

6. The method for preparing a rare earth aluminum nitride solid solution according to claim 1, characterized in that: In step 3, the amount of phosphoric acid added is 3.98%-11.9% of the mass of aluminum nitride, and the amount of cerium salt added is 10%-30% of the mass of aluminum nitride.

7. The method for preparing a rare earth aluminum nitride solid solution according to claim 6, characterized in that: The cerium salt is cerium chloride or cerium nitrate.

8. The method for preparing a rare earth aluminum nitride solid solution according to any one of claims 1 to 7, characterized in that: The thermal conductivity of the rare earth aluminum nitride solid solution powder is 0.201W / (m·K) to 0.355W / (m·K); the (101) crystal plane diffraction peak of aluminum nitride in the rare earth aluminum nitride solid solution powder product migrates to a low angle of 0.02° to 0.1°.

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