A Yttrium Magnesium Multiphase Nanopowder and Its Preparation Method
Yttrium magnesium multiphase nanoparticles were prepared by stepwise precipitation and low-temperature calcination, which solved the problems of uneven distribution and low sintering activity of yttrium magnesium multiphase nanoparticles and achieved an efficient and simple preparation process suitable for infrared window materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF CHEM MATERIAL CHINA ACADEMY OF ENG PHYSICS
- Filing Date
- 2026-03-27
- Publication Date
- 2026-05-26
AI Technical Summary
Existing methods for preparing yttrium magnesium multiphase nanopowders suffer from problems such as uneven two-phase distribution, low sintering activity, and complex processes with high energy consumption.
A stepwise precipitation strategy of first precipitating magnesium and then precipitating yttrium in situ was adopted. By controlling the pH value and the use of surfactants, a core-shell structure precursor of Y(OH)3 coated with Mg(OH)2 was generated and then calcined at low temperature.
The process achieves uniform distribution and excellent sintering activity of yttrium magnesium multiphase nanoparticles, reduces calcination temperature, simplifies the process flow, and avoids carbon pollution, making it suitable for industrial production.
Smart Images
Figure CN122079602A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nano-ceramic material preparation technology, and more specifically, to a method for preparing yttrium magnesium multiphase nanopowder and the prepared powder. Background Technology
[0002] Infrared imaging, infrared precision guidance, and infrared countermeasures technologies hold strategic importance in modern military applications. Infrared windows and fairings are key components of infrared technology. They need to bear the aerodynamic load and prevent external environmental factors from corroding and damaging the imaging system. While achieving the protection function, they also need to have high detection sensitivity and anti-interference capabilities. In order to meet the equipment requirements of the new generation of air-to-air missiles to effectively strike highly stealthy, highly maneuverable, and high-speed targets, and to adapt to the national defense needs of future air combat, the development of a new generation of infrared window materials that meet the following requirements has become a research hotspot and focus of various countries: (1) optical performance: high transmittance and low high-temperature infrared thermal emissivity; (2) mechanical performance: impact resistance, high hardness, and high strength; (3) thermodynamic performance: good thermal shock resistance and low coefficient of thermal expansion; (4) excellent chemical properties.
[0003] Y₂O₃ exhibits the smallest emissivity variation with wavelength, the lowest high-temperature infrared radiation coefficient at the same temperature, and low scattering rate, resulting in excellent high-temperature mechanical properties. However, pure-phase yttrium oxide has poor mechanical properties, making it unsuitable for hypersonic Mach applications. By introducing cubic MgO as a second phase to suppress Y₂O₃ grain growth, a new generation of infrared transparent materials with both excellent mechanical and optical properties can be obtained. Yttrium-magnesium multiphase nanoparticles serve as a key precursor for preparing this type of infrared transparent ceramic; their uniformity, purity, and particle size directly affect the density and optical properties of the subsequently sintered ceramics.
[0004] Currently, the main methods for preparing yttrium magnesium multiphase nanoparticles include the sol-gel method, the glycine-nitrate method, and the co-precipitation method. However, existing technologies still have the following problems:
[0005] Poor powder uniformity and uneven distribution of the two phases: In the traditional co-precipitation method, the precipitation pH values of Y³⁺ and Mg²⁺ are very different (Y³⁺ begins to precipitate at around pH 6-7, while Mg²⁺ only precipitates completely at around pH 10 or above), which leads to component segregation during precipitation and uneven distribution of the two phases after calcination, which seriously affects the density and optical properties of the sintered body.
[0006] Low sintering activity and easy grain coarsening: The powder prepared by existing methods has a large particle size or hard agglomeration, which leads to high sintering temperature and easy overgrowth of grains, making it difficult to obtain multiphase ceramics with both high density and fine grain structure.
[0007] The preparation process is long and energy consumption is high: traditional methods usually require multiple heat treatments and long drying times, which are complex and energy-intensive.
[0008] Therefore, developing a method for preparing yttrium magnesium multiphase nanopowder that can effectively solve the problem of uneven two-phase distribution and is simple and efficient has important application value. Summary of the Invention
[0009] This invention overcomes the shortcomings of the prior art by providing a method for preparing yttrium magnesium multiphase nanopowder and an embodiment of the prepared powder, in order to solve the problems of uneven two-phase distribution and low sintering activity of yttrium magnesium multiphase nanopowder in the prior art.
[0010] To solve the above-mentioned technical problems, one embodiment of the present invention adopts the following technical solution:
[0011] A method for preparing yttrium magnesium multiphase nanopowder includes the following steps:
[0012] Step 1, Magnesium Source Precipitation: Dissolve the magnesium source in deionized water to prepare a magnesium salt solution. Under stirring conditions, add the precipitant to the magnesium salt solution to carry out a precipitation reaction, generating Mg(OH)₂ precipitate. The magnesium source is selected from at least one of magnesium nitrate, magnesium chloride, and magnesium acetate; the precipitant is at least one of ammonia and sodium hydroxide; the final pH value of the reaction is controlled at 10.5-12.0.
[0013] Step 2, in-situ precipitation of yttrium source: A yttrium source solution is slowly added to the system containing Mg(OH)₂ precipitate obtained in Step 1, while a precipitating agent is added simultaneously. The pH of the system is adjusted to 6.5-8.0, allowing Y³⁺ to precipitate in situ on the surface of Mg(OH)₂ particles, generating a core-shell structured precursor of Y(OH)₃ coating Mg(OH)₂. The yttrium source is selected from at least one of yttrium nitrate and yttrium chloride; the molar ratio of yttrium to magnesium is 1:1 to 3:1.
[0014] Step 3, Aging and Washing: The core-shell structure precursor obtained in Step 2 is aged at a temperature of 50-80℃ for 2-12 hours; then washed, separated and dried to obtain composite precursor powder.
[0015] Step 4, low-temperature calcination: The composite precursor powder obtained in step 3 is calcined at a temperature of 600-750℃, a heating rate of 1-3℃ / min, and a holding time of 2-4 hours to completely decompose the hydroxide and obtain the yttrium magnesium multiphase nanopowder.
[0016] Preferably, a surfactant may be added in step two. The surfactant is selected from at least one of polyethylene glycol and polyvinylpyrrolidone, and the amount added is 0.5-2% of the total mass of the metal ions.
[0017] Compared with the prior art, the present invention has at least the following beneficial effects:
[0018] This invention employs a stepwise precipitation strategy of "first precipitating magnesium, then precipitating yttrium in situ," which enables Y³⁺ to be uniformly coated on the surface of the formed Mg(OH)₂ particles. This overcomes the component segregation problem caused by the pH difference between Y³⁺ and Mg²⁺ precipitation in traditional coprecipitation methods, achieving uniform distribution of the two phases at the nanoscale. This lays the material foundation for the subsequent preparation of high-performance multiphase transparent ceramics.
[0019] The core-shell structure precursor prepared by this invention has different decomposition temperatures of Y(OH)3 and Mg(OH)2 during calcination, forming a unique micro-stress field that helps to further refine the grains. The resulting powder has a small particle size (average size 50nm), no hard agglomerates, and excellent sintering activity, which can effectively reduce the subsequent ceramic sintering temperature.
[0020] This invention employs conventional precipitation and calcination processes, eliminating the need for organic complexing agents such as citric acid and ethylene glycol, or fuels, thus avoiding carbon pollution at the source. Furthermore, the calcination temperature is as low as 600-750℃, making the process simple, energy-efficient, environmentally friendly, and easy to scale up for industrial production. Attached Figure Description
[0021] Figure 1 This is a SEM image of the yttrium magnesium multiphase nanopowder prepared in Example 1 of the present invention.
[0022] Figure 2 The TEM image shows the yttrium magnesium multiphase nanopowder prepared in Example 1 of this invention. Detailed Implementation
[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0024] A method for preparing yttrium magnesium multiphase nanopowder
[0025] [Example 1]
[0026] Step 1, Magnesium source precipitation: Dissolve magnesium nitrate in deionized water to prepare a 0.5 mol / L magnesium salt solution. Under stirring, add ammonia dropwise until the pH reaches 11.5, forming Mg(OH)₂ precipitate.
[0027] Step 2, in-situ precipitation of yttrium source: Slowly add yttrium nitrate solution (Y:Mg molar ratio = 1:1) to the above system, while adding ammonia water to maintain the pH of the system between 7.0 and 7.5, so that Y³⁺ precipitates in situ on the surface of Mg(OH)₂ particles, generating a core-shell structure precursor of Y(OH)₃ coating Mg(OH)₂.
[0028] Step 3, aging and washing: The obtained slurry is aged at 60°C for 6 hours, then washed three times with deionized water and ethanol, centrifuged, and dried at 80°C for 12 hours to obtain composite precursor powder.
[0029] Step 4, low-temperature calcination: The precursor is placed in a muffle furnace and heated to 700°C at a rate of 2°C / min. The temperature is maintained for 3 hours and then naturally cooled to obtain yttrium magnesium multiphase nanoparticles.
[0030] like Figure 1 The obtained powder, as determined by XRD, was a pure-phase cubic Y₂O₃ and MgO. Figure 2 TEM observations showed that the average particle size of the powder was approximately 18 nm, and the two phases were evenly distributed.
[0031] [Example 2]
[0032] Step 1, Magnesium source precipitation: Dissolve magnesium acetate in deionized water to prepare a 0.8 mol / L magnesium salt solution. Under stirring, add sodium hydroxide solution dropwise until the pH reaches 12.0, forming Mg(OH)₂ precipitate.
[0033] Step 2, in-situ precipitation of yttrium source: Add polyethylene glycol (1% of the total mass of metal ions) to the above system, stir evenly, and then slowly add yttrium chloride solution (Y:Mg molar ratio = 1:1) while adding sodium hydroxide to maintain the pH of the system between 6.8 and 7.2 to generate a core-shell structure precursor.
[0034] Step 3, aging and washing: The obtained slurry is aged at 70°C for 4 hours, then washed, separated and dried to obtain composite precursor powder.
[0035] Step 4, low-temperature calcination: The precursor is calcined at 650℃ for 2 hours with a heating rate of 1℃ / min to obtain yttrium magnesium multiphase nanoparticles.
[0036] The average particle size of the obtained powder is about 50 nm.
[0037] Although the invention has been described herein with reference to illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter combination within the scope of this disclosure. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.
Claims
1. A method for preparing yttrium magnesium multiphase nanopowder, characterized in that, Includes the following steps: Step 1, Magnesium source precipitation: The magnesium source reacts with a precipitant to generate Mg(OH)2 precipitate; Step 2, Yttrium source in-situ precipitation: Yttrium source is added to the system containing Mg(OH)2 precipitate obtained in Step 1, and the pH is controlled to allow Y³⁺ to precipitate in-situ on the surface of Mg(OH)2, forming a core-shell structure precursor of Y(OH)3 coating Mg(OH)2; Step 3, Aging and washing: The core-shell structure precursor obtained in Step 2 is aged, washed, separated, and dried to obtain composite precursor powder; Step 4, Low-temperature calcination: The composite precursor powder obtained in Step 3 is calcined to obtain the yttrium magnesium multiphase nanoparticles.
2. The method for preparing yttrium magnesium multiphase nanopowder according to claim 1, characterized in that: In step one, the magnesium source is selected from magnesium nitrate, magnesium chloride, or magnesium acetate, the precipitant is ammonia or sodium hydroxide, and the final pH of the reaction is 10.5-12.
0.
3. The method for preparing yttrium magnesium multiphase nanopowder according to claim 1, characterized in that: In step two, the yttrium source is selected from yttrium nitrate or yttrium chloride. During the in-situ precipitation process, the pH of the system is controlled at 6.5-8.0, and the molar ratio of yttrium to magnesium is 1:1 to 3:
1.
4. The method for preparing yttrium magnesium multiphase nanopowder according to claim 1, characterized in that: In step two, a surfactant may be added, which is selected from polyethylene glycol or polyvinylpyrrolidone, and the amount added is 0.5-2% of the total mass of metal ions.
5. The method for preparing yttrium magnesium multiphase nanopowder according to claim 1, characterized in that: In step three, the aging temperature is 50-80℃ and the aging time is 2-12 hours.
6. The method for preparing yttrium magnesium multiphase nanopowder according to claim 1, characterized in that: In step four, the calcination temperature is 600-750℃, the heating rate is 1-3℃ / min, and the holding time is 2-4 hours.
7. The yttrium magnesium multiphase nanopowder prepared by the method according to any one of claims 1 to 6, characterized in that: The powder has an average particle size of 50 nm and the two phases are evenly distributed.