A porous magnesium-aluminum spinel@silicon nitride magnesium whisker composite powder and a preparation method thereof

Abstract

The present application relates to a kind of porous magnesium-aluminum spinel@silicon nitride magnesium whisker composite powder and preparation method thereof.The technical scheme is: with isopropyl alcohol aluminum as aluminum source, with polyethylene glycol as porous template agent and with silicon nitride magnesium whisker as carrier, isopropyl alcohol aluminum is dissolved in isopropyl alcohol, stirring, to obtain mixed solution I;Silicon nitride magnesium whisker is added to mixed solution I, ultrasonic dispersion, to obtain mixed solution II.Dilute hydrochloric acid is added to mixed solution II, under water bath condition, magnetic stirring, to prepare alumina monohydrate@silicon nitride magnesium sol, then polyethylene glycol is added, oscillation in ultrasonic wave oscillator, to obtain sol-gel;Sol-gel is extracted, washed, dried, ground, to obtain coated powder;Coated powder is kept at 1100-1200 DEG C under inert atmosphere, with furnace cooling, broken, screening, to prepare porous magnesium-aluminum spinel@silicon nitride magnesium whisker composite powder.The shell structure of the present application is controllable, and the prepared product has high core-shell bonding strength, strong stability and excellent oxidation resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of silicon magnesium nitride whiskers, and particularly relates to porous magnesium aluminum spinel@silicon magnesium nitride whisker composite powder and a preparation method thereof. BACKGROUND

[0002] One-dimensional silicon magnesium nitride whiskers have very small particle sizes, and are difficult to accommodate in defects commonly present in large crystals, have high atomic order, and have a strength close to the theoretical value of a complete crystal, and thus have good high-temperature resistance, corrosion resistance and electrical insulation, and have the characteristics of light weight, high strength, high elastic modulus and high hardness, and when used as modified reinforcing materials for plastics, metals, ceramics and the like, show excellent physical, chemical and mechanical properties. Z. The research of L. Pentráková, M. Hrabalová, et al. Decomposition of MgSiN2 in nitrogen atmosphere [J]. Journal of the European Ceramic Society, 2011, (31): 1473-1480. pointed out that silicon magnesium nitride decomposes at 1400 DEG C, indicating that the high-temperature stability of silicon magnesium nitride is poor. Therefore, the research and use of silicon magnesium nitride whiskers have attracted the attention of scientific and technological personnel.

[0003] The patent technology "Preparation of silicon magnesium nitride super-long nanowires and nanobands" (CN202210073687.6) uses 96-50% silicon powder and 4-50% magnesium oxide powder as mixed ceramic powder, and the mixed ceramic powder is pressed into a ceramic blank, and a nitrogenization reaction is carried out at 1380-1450 DEG C. Although silicon magnesium nitride super-long nanowires and nanobands are obtained on the inner surface of the crucible, the one-dimensional silicon magnesium nitride super-long nanowires and nanobands prepared by this method are easily eroded by oxygen at high temperatures, resulting in poor oxidation resistance of the material, which limits the development of silicon magnesium nitride whiskers in high-temperature and ultra-high-temperature fields.

[0004] The research of Wang Wei, Guan Jian-guo, Wang Qi. Effect of milling time on structure and properties of Fe-ZnO core-shell nanocomposite particles [J]. Journal of Inorganic Materials, 2005, 20(3): 599-607. and Zhang Juxian, Gao Longqiao. Study on chemical preparation process of Al2O3 / SiCp nanocomposite materials [J]. Journal of the Chinese Ceramic Society, 2001, 29(6): 550-553. pointed out that the use of high-energy ball milling and gel injection molding to prepare coated composite powder can achieve simple coating modification, but cannot control the structure and morphology of the coating shell, affecting the high-temperature stability.

[0005] The patented technology "Magnesium Oxide@Silicon Magnesium Nitride Powder Based on High-Silicon Magnesium Oxide and Its Preparation Method" (CN 115465845 A) uses carbothermic magnesium thermal reduction to prepare magnesium oxide-coated silicon magnesium nitride composite powder. However, the modified silicon magnesium nitride powder prepared by this technology has poor bonding between the outer shell and the core, and is easy to fall off. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of existing technologies and provides a method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder with controllable shell structure. The porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder prepared by this method has high core-shell bonding strength, strong high-temperature stability and excellent oxidation resistance.

[0007] To achieve the above objectives, the specific steps of the technical solution adopted by the present invention are as follows:

[0008] Step 1: Using 45-55 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0009] Step 2: Using 45-55 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0010] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3-4; stir magnetically at 800-1000 r / min for 1-3 h under water bath conditions of 70-90℃, and reflux for 15-20 h to obtain hydrated alumina@silicon magnesium nitride sol.

[0011] Step 4: Add 15-20 parts by weight of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, and then place it in an ultrasonic oscillator and oscillate for 10-20 minutes to obtain a sol-gel.

[0012] Step 5: Filter the sol-gel, wash it 1 to 6 times with distilled water, dry it at 100 to 120°C for 19 to 24 hours, take it out and grind it to obtain the coated powder.

[0013] Step 6: Place the coated powder in a tube furnace and heat it to 1100-1200°C at a rate of 5-10°C / min under an inert atmosphere. Hold the temperature for 3-5 hours and cool it with the furnace. Crush and sieve the powder to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0014] The purity of the aluminum isopropoxide is ≥98%.

[0015] The purity of the isopropanol is ≥98%.

[0016] The MgSiN2 content of the silicon magnesium nitride whiskers is ≥99.5wt%; the particle size of the silicon magnesium nitride whiskers is <0.045mm.

[0017] The HCl content of the dilute hydrochloric acid is ≤10wt%.

[0018] The purity of the polyethylene glycol is ≥98%.

[0019] The inert atmosphere is one of argon and nitrogen, or a mixture of argon and nitrogen.

[0020] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0021] This invention employs a sol-gel template method to prepare porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder at a relatively low temperature. Polyethylene glycol (PEG) micelles, which encapsulate and connect particles in the sol-gel system, enhance the structural integrity of the porous PEG@silicon nitride magnesium whisker composite powder. Furthermore, PEG micelles restrict the growth of individual particles and prevent the aggregation of connected particles into clusters. Simultaneously, PEG is used as a template agent; it can be removed by high-temperature calcination, leaving numerous small pores in the product. These pores act as templates, promoting the formation of a porous core-shell structure in the PEG@silicon nitride magnesium whisker composite powder, thus achieving controllable shell structure.

[0022] This invention utilizes magnesium aluminum spinel as the outer shell of silicon nitride magnesium whiskers. The magnesium vapor generated from the decomposition of silicon nitride magnesium whiskers has an excellent regulatory effect on the structure of magnesium aluminum spinel, allowing it to stably exist on the surface of the silicon nitride magnesium whiskers. Simultaneously, the magnesium aluminum spinel shell and the silicon nitride magnesium core promote ion exchange, thereby fostering a strong interfacial bond between the shell and the core, and increasing the bonding strength between the magnesium aluminum spinel shell and the silicon nitride magnesium core.

[0023] This invention utilizes the "porous network channel" shell structure to prepare porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder. Since the stability of silicon nitride magnesium whiskers is controlled by the nitrogen partial pressure in the environment, this invention utilizes the locally high nitrogen partial pressure within the porous channels to improve the high-temperature stability of the silicon nitride magnesium whiskers, achieving an integration of structure and function.

[0024] The porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder prepared by this invention not only has a controllable core-shell structure, high core-shell bonding strength and strong high-temperature stability, but also reduces the contact surface between silicon nitride magnesium whiskers and oxygen through the magnesium aluminum spinel shell, thereby reducing the oxidation activity of silicon nitride magnesium whiskers and effectively improving the oxidation resistance of silicon nitride magnesium whiskers.

[0025] Therefore, the porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder prepared by this invention has the characteristics of controllable shell structure, high core-shell bonding strength, strong stability and excellent oxidation resistance. Detailed Implementation

[0026] The following detailed description of the embodiments further illustrates the present invention, but is not intended to limit its scope of protection.

[0027] A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0028] Step 1: Using 45-55 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0029] Step 2: Using 45-55 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0030] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3-4; stir magnetically at 800-1000 r / min for 1-3 h under water bath conditions of 70-90℃, and reflux for 15-20 h to obtain hydrated alumina@silicon magnesium nitride sol.

[0031] Step 4: Add 15-20 parts by weight of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, and then place it in an ultrasonic oscillator and oscillate for 10-20 minutes to obtain a sol-gel.

[0032] Step 5: Filter the sol-gel, wash it 1 to 6 times with distilled water, dry it at 100 to 120°C for 19 to 24 hours, take it out and grind it to obtain the coated powder.

[0033] Step 6: Place the coated powder in a tube furnace and heat it to 1100-1200°C at a rate of 5-10°C / min under an inert atmosphere. Hold the temperature for 3-5 hours and cool it with the furnace. Crush and sieve the powder to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0034] The purity of the aluminum isopropoxide is ≥98%.

[0035] The purity of the isopropanol is ≥98%.

[0036] The MgSiN2 content of the silicon magnesium nitride whiskers is ≥99.5wt%; the particle size of the silicon magnesium nitride whiskers is <0.045mm.

[0037] The HCl content of the dilute hydrochloric acid is ≤10wt%.

[0038] The purity of the polyethylene glycol is ≥98%.

[0039] The inert atmosphere is one of argon and nitrogen, or a mixture of argon and nitrogen.

[0040] The details will not be repeated in the examples.

[0041] Example 1

[0042] A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0043] Step 1: Using 45 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0044] Step 2: Using 55 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0045] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3; stir magnetically at 800 r / min for 1 hour under water bath conditions at 70℃, and reflux for 15 hours to obtain hydrated alumina@silicon magnesium nitride sol.

[0046] Step 4: Add 15 parts by weight of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, then place it in an ultrasonic oscillator and oscillate for 10 minutes to obtain a sol-gel.

[0047] Step 5: Filter the sol-gel, wash it once with distilled water, dry it at 100°C for 19 hours, take it out and grind it to obtain coated powder.

[0048] Step 6: Place the coated powder in a tube furnace, heat it to 1100°C at a rate of 5°C / min under nitrogen conditions, hold it at that temperature for 3 hours, and then cool it with the furnace; crush and sieve it to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0049] Example 2

[0050] A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0051] Step 1: Using 47 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0052] Step 2: Using 53 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0053] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3.2; stir magnetically at 840 r / min for 1.4 h under water bath conditions at 74℃, and reflux for 16 h to obtain hydrated alumina@silicon magnesium nitride sol.

[0054] Step 4: Add 16 parts by mass of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, then place it in an ultrasonic oscillator and oscillate for 12 minutes to obtain a sol-gel.

[0055] Step 5: Filter the sol-gel, wash it twice with distilled water, dry it at 104°C for 20 hours, take it out and grind it to obtain the coated powder.

[0056] Step 6: Place the coated powder in a tube furnace and heat it to 1120°C at a rate of 6°C / min under nitrogen conditions. Hold the temperature for 3.4 hours and then cool it with the furnace. Crush and sieve the powder to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0057] Example 3

[0058] A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0059] Step 1: Using 49 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0060] Step 2: Using 51 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0061] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3.4; stir magnetically at 880 r / min for 1.8 h under water bath conditions at 78℃, and reflux for 17 h to obtain hydrated alumina@silicon magnesium nitride sol.

[0062] Step 4: Add 17 parts by weight of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, then place it in an ultrasonic oscillator and oscillate for 14 minutes to obtain a sol-gel.

[0063] Step 5: Filter the sol-gel, wash it three times with distilled water, dry it at 108°C for 21 hours, take it out and grind it to obtain the coated powder.

[0064] Step 6: Place the coated powder in a tube furnace and heat it to 1140°C at a rate of 7°C / min under argon atmosphere. Hold the temperature for 3.8 hours and then cool it with the furnace. Crush and sieve the powder to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0065] Example 4

[0066] A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0067] Step 1: Using 51 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0068] Step 2: Using 49 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0069] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3.6; stir magnetically at 920 r / min for 2.2 h under water bath conditions at 82℃, and reflux for 18 h to obtain hydrated alumina@silicon magnesium nitride sol.

[0070] Step 4: Add 18 parts by weight of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, then place it in an ultrasonic oscillator and oscillate for 16 minutes to obtain a sol-gel.

[0071] Step 5: Filter the sol-gel, wash it 4 times with distilled water, dry it at 112°C for 22 hours, take it out and grind it to obtain the coated powder.

[0072] Step 6: Place the coated powder in a tube furnace and heat it to 1160°C at a rate of 8°C / min under argon atmosphere. Hold the temperature for 4.2 hours and then cool it with the furnace. Crush and sieve the powder to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0073] Example 5

[0074] A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0075] Step 1: Using 53 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0076] Step 2: Using 47 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0077] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3.8; stir magnetically at 960 r / min for 2.6 h under water bath conditions at 86℃, and reflux for 19 h to obtain hydrated alumina@silicon magnesium nitride sol.

[0078] Step 4: Add 19 parts by mass of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, then place it in an ultrasonic oscillator and oscillate for 18 minutes to obtain a sol-gel.

[0079] Step 5: Filter the sol-gel, wash it 5 times with distilled water, dry it at 116°C for 23 hours, take it out and grind it to obtain the coated powder.

[0080] Step 6: Place the coated powder in a tube furnace and heat it to 1180°C at a rate of 9°C / min under a mixed gas of nitrogen and argon, hold it at that temperature for 4.6 hours, and then cool it with the furnace; crush and sieve it to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0081] Example 6

[0082] A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder and its preparation method. The preparation method described in this specific embodiment is as follows:

[0083] Step 1: Using 55 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I.

[0084] Step 2: Using 45 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II.

[0085] Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 4; stir magnetically at 1000 r / min for 3 h in a water bath at 90℃, and reflux for 20 h to obtain hydrated alumina@silicon magnesium nitride sol.

[0086] Step 4: Add 20 parts by weight of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, then place it in an ultrasonic oscillator and oscillate for 20 minutes to obtain a sol-gel.

[0087] Step 5: Filter the sol-gel, wash it 6 times with distilled water, dry it at 120°C for 24 hours, take it out and grind it to obtain the coated powder.

[0088] Step 6: Place the coated powder in a tube furnace and heat it to 1200°C at a rate of 10°C / min under a mixed gas of nitrogen and argon, hold it at that temperature for 5 hours, and then cool it with the furnace; crush and sieve it to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

[0089] This specific implementation method has the following advantages compared with the prior art:

[0090] This specific embodiment employs a sol-gel template method to prepare porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder at a relatively low temperature. Polyethylene glycol micelles are utilized in the sol-gel system to encapsulate and connect particles, improving the structural integrity of the porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder. Furthermore, polyethylene glycol micelles restrict the growth of individual particles and prevent the aggregation of connected particles into clusters. Simultaneously, polyethylene glycol is used as a template agent; it can be removed by high-temperature calcination, leaving numerous small pores in the product, which act as a template to promote the formation of a porous core-shell structure in the magnesium aluminum spinel@silicon nitride magnesium whisker composite powder, achieving controllable shell structure.

[0091] This specific embodiment utilizes magnesium aluminum spinel as the outer shell of silicon nitride magnesium whiskers. The magnesium vapor generated by the decomposition of silicon nitride magnesium whiskers has an excellent regulatory effect on the structure of magnesium aluminum spinel, allowing it to stably exist on the surface of silicon nitride magnesium whiskers. Simultaneously, the magnesium aluminum spinel shell and the silicon nitride magnesium core promote ion exchange, thereby fostering a strong interfacial bond between the shell and the core, and increasing the bonding strength between the magnesium aluminum spinel shell and the silicon nitride magnesium core.

[0092] This specific embodiment utilizes the "porous network channel" shell structure to prepare a porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder. Since the stability of silicon nitride magnesium whiskers is controlled by the nitrogen partial pressure in the environment, this specific embodiment utilizes the locally high nitrogen partial pressure of the porous channels to improve the high-temperature stability of the silicon nitride magnesium whiskers, achieving integration of structure and function.

[0093] The porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder prepared in this specific embodiment not only has a controllable core-shell structure, high core-shell bonding strength and strong high-temperature stability, but also reduces the contact surface between silicon nitride magnesium whiskers and oxygen through the magnesium aluminum spinel shell, thereby reducing the oxidation activity of silicon nitride magnesium whiskers and effectively improving the oxidation resistance of silicon nitride magnesium whiskers.

[0094] Therefore, the porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder prepared by this invention has the characteristics of controllable shell structure, high core-shell bonding strength, strong stability and excellent oxidation resistance.

Claims

1. A method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder, characterized in that... The steps of the preparation method are as follows: Step 1: Using 45-55 parts by mass of aluminum isopropoxide as the aluminum source, dissolve the aluminum isopropoxide in isopropanol and stir to obtain mixed solution I; Step 2: Using 45-55 parts by mass of magnesium silicon nitride whiskers as a carrier, the magnesium silicon nitride whiskers are added to the mixed solution I, and then ultrasonically dispersed and magnetically stirred to obtain mixed solution II. Step 3: Add dilute hydrochloric acid to the mixed solution II to adjust the pH value to 3-4; under water bath conditions of 70-90℃, magnetically stir at a speed of 800-1000 r / min for 1-3 hours, and reflux for 15-20 hours to obtain hydrated alumina@silicon magnesium nitride sol. Step 4: Add 15-20 parts by weight of polyethylene glycol to the monohydrated alumina@silicon magnesium nitride sol, and then place it in an ultrasonic oscillator and oscillate for 10-20 minutes to obtain a sol-gel. Step 5: Filter the sol-gel, wash it with distilled water 1 to 6 times, dry it at 100 to 120°C for 19 to 24 hours, take it out and grind it to obtain the coated powder; Step 6: Place the coated powder in a tube furnace and heat it to 1100-1200°C at a rate of 5-10°C / min under an inert atmosphere. Hold the temperature for 3-5 hours and cool it with the furnace. Crush and sieve the powder to obtain porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder.

2. The method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder according to claim 1, characterized in that, The purity of the aluminum isopropoxide is ≥98%.

3. The method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder according to claim 1, characterized in that, The purity of the isopropanol is ≥98%.

4. The method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder according to claim 1, characterized in that, The MgSiN2 content of the silicon magnesium nitride whiskers is ≥99.5wt%; the particle size of the silicon magnesium nitride whiskers is <0.045mm.

5. The method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder according to claim 1, characterized in that, The HCl content of the dilute hydrochloric acid is ≤10wt%.

6. The method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder according to claim 1, characterized in that, The purity of the polyethylene glycol is ≥98%.

7. The method for preparing porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder according to claim 1, characterized in that... The inert atmosphere is one of argon and nitrogen, or a mixture of argon and nitrogen.

8. A porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder, characterized in that... The porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder is prepared according to the preparation method of porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder in any one of claims 1 to 7. The porous magnesium aluminum spinel@silicon nitride magnesium whisker composite powder has a core-shell structure, with magnesium aluminum spinel coating the surface of silicon nitride magnesium whiskers in the form of a porous shell.