Synthesis method of Cr < 3 + >-doped magnesium aluminum oxide nano-powder

Abstract

The invention relates to the technical field of preparation methods of nano precursor powder, in particular to a synthesis method of Cr < 3 + > doped magnesium aluminum oxide nano powder, which comprises the following steps: weighing magnesium nitrate, aluminum nitrate and chromic nitrate according to the stoichiometric ratio of MgAl2-xO4: xCr < 3 + >; stirring and mixing the prepared magnesium nitrate solution, aluminum nitrate solution and chromic nitrate solution together to prepare a mixed solution I; ammonia water is dripped into the first mixed solution, then the first mixed solution dripped with the ammonia water is stirred and mixed, and a second mixed solution is prepared; pouring the mixed solution II into a high-pressure reaction kettle, and putting the high-pressure reaction kettle into a constant-temperature box for reaction to prepare a white precipitate; adding deionized water into the white precipitate for washing and precipitating, and centrifuging to obtain white precipitate powder; drying the white precipitate powder at a constant temperature; calcining the dried white precipitate powder to prepare nano precursor powder; the prepared nanometer precursor powder has the advantages of being high in purity and small in particle size.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr 3+ The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr BACKGROUND

[0002] The nano ceramic precursor powder is a metastable intermediate substance with a size of nanometer, which is between a solid and a molecule, has unique performance and wide application prospect as a basic material for preparing a nano ceramic.

[0003] A traditional nano ceramic preparation process needs to be treated by ball milling for a long time to realize uniform mixing of powder, impurity particles generated by abrasion of a grinding medium are easily introduced in the process, secondary pollution is caused, and the purity of the prepared nano precursor powder is reduced. SUMMARY

[0004] The application aims to provide a preparation method of a Cr 3+ The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0005] To achieve the above-mentioned purpose, the application provides a preparation method of a Cr 3+ The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0006] The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr 2-x O4: xCr 3+ The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0007] The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0008] The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0009] The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0010] The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0011] The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr The application relates to a preparation method of a nano precursor powder, in particular to a preparation method of a Cr

[0012] The white precipitate powder was dried at a constant temperature.

[0013] The dried white precipitate powder was calcined to obtain nano-precursor powder.

[0014] Among them, magnesium nitrate, aluminum nitrate, and chromium nitrate are used as raw materials, according to MgAl 2-x O4:xCr 3+ In the step of weighing magnesium nitrate, aluminum nitrate, and chromium nitrate according to their stoichiometric ratios for later use...

[0015] The raw materials used are magnesium nitrate, aluminum nitrate, and chromium nitrate with analytical purity standards.

[0016] In the step of mixing magnesium nitrate solution, aluminum nitrate solution, and chromium nitrate solution together to prepare mixed solution one,

[0017] The mixing time for magnesium nitrate solution, aluminum nitrate solution and chromium nitrate solution is 5-30 min, and the stirring rate is 500 r / min.

[0018] In one step, ammonia water is added dropwise to mixed solution one until the pH value of mixed solution one is 3-9, and then the mixed solution one with added ammonia water is stirred to obtain mixed solution two.

[0019] The mixing time for adding ammonia water dropwise to the mixed solution is 10-40 minutes, and the stirring speed is 500 r / min.

[0020] In one step, the mixed solution 2 is poured into a high-pressure reactor and placed in a constant temperature chamber to react and obtain a white precipitate.

[0021] The reaction temperature of mixed solution 2 in the constant temperature chamber is 100-180℃.

[0022] In one step, the mixed solution 2 is poured into a high-pressure reactor and placed in a constant temperature chamber to react and obtain a white precipitate.

[0023] The reaction time of mixed solution 2 in the constant temperature incubator is 10-24 hours.

[0024] The specific steps for drying the white precipitate powder at a constant temperature include:

[0025] The white precipitated powder was placed in a drying oven for constant temperature drying.

[0026] The specific steps for preparing nano-precursor powder by calcining the dried white precipitate powder include:

[0027] The dried white precipitate powder was placed in a muffle furnace for calcination.

[0028] One step involves calcining the dried white precipitate powder in a muffle furnace.

[0029] The calcination temperature of the white precipitated powder is 600-1200℃.

[0030] One step involves calcining the dried white precipitate powder in a muffle furnace.

[0031] The calcination time for white precipitated powder is 1-6 hours.

[0032] A Cr 3+ A method for synthesizing magnesium aluminum oxide nanopowder is presented, using a hydrothermal synthesis method to obtain nano-sized precursor particles. This avoids the damage to grains caused by ball milling during precursor preparation, solving the problem that existing nano-ceramic preparation processes require prolonged ball milling to achieve uniform powder mixing. This process easily introduces impurities generated by grinding media wear, leading to secondary contamination and reducing the purity of the obtained nano-precursor powder. The precursor has a magnesium aluminum spinel structure, and magnesium aluminum spinel has good optical transmittance, wear resistance, corrosion resistance, high temperature resistance, impact resistance, high hardness and flexural strength, as well as excellent electrical insulation and chemical stability, making it an ideal functional material. Experiments show that MgAl2O4 has certain radiation resistance properties and has long been used as a reactor wall material and a material for encapsulating nuclear waste. Therefore, developing laser materials based on MgAl2O4 could provide laser working materials for fields such as plasma diagnostics in large melting reactors, uranium isotope separation, space science research, and space communication. This invention prepares Cr... 3+ Magnesium oxide aluminum nano-precursor. The crystal phase is better formed by heat treatment in a solvothermal reactor. The reaction temperature, time, and pH value are adjusted to obtain nanoscale powder. The powder prepared by the method provided in this invention has advantages such as high purity, fine particle size, good sintering performance, and good luminescence properties. Furthermore, the preparation method is simple, has high production efficiency, and is suitable for industrial production. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0034] Figure 1 This invention relates to a type of Cr 3+ A flowchart of the synthesis method for doped magnesium aluminate nanoparticles.

[0035] Figure 2 This is the XRD pattern of the nano-precursor powder of the present invention.

[0036] Figure 3This is a SEM image of the nano-precursor powder of the present invention.

[0037] Figure 4 This is the emission spectrum of the nano-precursor powder of the present invention. Detailed Implementation

[0038] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0039] Please see Figures 1-4 This invention provides a Cr 3+ Methods for synthesizing doped magnesium alumina nanopowders include:

[0040] S1 uses magnesium nitrate, aluminum nitrate, and chromium nitrate as raw materials, following the MgAl... 2-x O4:xCr 3+ According to the stoichiometric ratio, weigh out magnesium nitrate, aluminum nitrate and chromium nitrate respectively for later use;

[0041] In this step, the raw materials used are magnesium nitrate, aluminum nitrate, and chromium nitrate with analytical purity standards.

[0042] S2. Magnesium nitrate, aluminum nitrate, and chromium nitrate are added to water and stirred until completely dissolved to obtain magnesium nitrate solution, aluminum nitrate solution, and chromium nitrate solution.

[0043] In this step, the raw materials and water are mixed in a ratio of 1:5.

[0044] S3 involves mixing magnesium nitrate solution, aluminum nitrate solution, and chromium nitrate solution together to obtain mixed solution one.

[0045] In this step, the magnesium nitrate solution, aluminum nitrate solution, and chromium nitrate solution are stirred for 5-30 minutes at a stirring rate of 500 r / min.

[0046] S4. Add ammonia water dropwise to mixed solution one until the pH value of mixed solution one is 3-9. Then stir and mix mixed solution one with added ammonia water to obtain mixed solution two.

[0047] In this step, the mixing time for adding ammonia water dropwise to the mixed solution is 10-40 minutes, and the stirring speed is 500 r / min.

[0048] S5. Pour the mixed solution 2 into the high-pressure reactor and place it in a constant temperature chamber to react, thus obtaining a white precipitate.

[0049] In this step, the solution is poured into a reaction vessel, which is then sealed and placed in a constant temperature chamber for heating. The reaction temperature of mixed solution two in the constant temperature chamber is 100-180℃. The reaction time of mixed solution two in the constant temperature chamber is 10-24 hours.

[0050] S6 Add deionized water to the white precipitate to wash the precipitate, and centrifuge to obtain white precipitate powder;

[0051] S7 dries the white precipitated powder at a constant temperature;

[0052] The specific steps include: placing the white precipitated powder in a drying oven for constant temperature drying, where the temperature is 80℃ and the time is 24 hours.

[0053] S8 was used to calcine the dried white precipitate powder to obtain nano precursor powder.

[0054] The specific steps include: placing the dried white precipitate powder in a muffle furnace for calcination. The calcination temperature of the white precipitate powder is 600-1200℃. The calcination time is 1-6 hours.

[0055] refer to Figure 2 The XRD patterns of the nano-precursor powder samples showed good matching between the diffraction peaks and the JCPDS standard card of MgAl2O4, indicating that Cr 3+ Ions are introduced into the matrix. The microstructure of the nano-precursor powder sample is as follows: Figure 3 As shown, the powder mainly consists of rod-shaped particles, with larger particles approximately 100 nm long and 40 nm wide. The powder is uniformly distributed and exhibits minimal agglomeration. The prepared sample is a nanoparticle with a small particle size, eliminating the need for ball milling and avoiding secondary contamination that could reduce powder purity. (Reference) Figure 4 When the excitation wavelength is 552 nm, the emission spectrum of the nano-precursor powder sample is mainly composed of the emission peak at 693 nm, and the sample emits red light.

[0056] Crystal structure analysis: such as Figure 2 As shown, the XRD pattern of the nano-precursor powder sample shows that the position and intensity of its diffraction peaks match well with the JCPDS: 21-1152 standard card for MgAl2O4, with no obvious impurity peaks appearing. This result indicates that the sample formed a MgAl2O4 crystal structure, and Cr... 3+ The ions successfully entered the crystal lattice of the MgAl2O4 matrix without significantly damaging the crystal structure of the matrix.

[0057] Microstructure analysis: The microstructure of the nano-precursor powder sample was analyzed through... Figure 3It can be clearly observed that the powder particles are mainly rod-shaped with relatively regular morphology. The larger particles are approximately 100 nm long and 40 nm wide, with a relatively uniform overall particle size distribution and minimal agglomeration, indicating good dispersibility. Furthermore, since the sample itself is already a nanoscale powder with a small particle size (overall within the nanoscale range), subsequent grinding processes such as ball milling are unnecessary. This effectively avoids secondary contamination caused by impurities that may be introduced during ball milling, and also reduces damage to the powder's crystal structure caused by mechanical grinding, thus helping to maintain the powder's high purity.

[0058] Luminescent performance analysis: by Figure 4 The fluorescence emission spectrum of the sample shows that when 552 nm is used as the excitation wavelength, the emission spectrum of the nano precursor powder sample exhibits a distinct characteristic emission peak, which is mainly located at 693 nm, belonging to the red light band (620-750 nm). This indicates that the sample can stably emit red light under 552 nm light excitation.

[0059] This invention discloses a method for synthesizing Cr3+-doped magnesium aluminum oxide nanopowder. The method utilizes a hydrothermal synthesis to obtain nano-sized precursor particles, avoiding the damage to grains caused by ball milling during precursor preparation. This solves the problem in existing nano-ceramic preparation processes where prolonged ball milling is required to achieve uniform powder mixing. This process easily introduces impurities generated by grinding media wear, leading to secondary contamination and reducing the purity of the resulting nano-precursor powder. The precursor possesses a magnesium aluminum spinel structure, which exhibits good optical transmittance, wear resistance, corrosion resistance, high temperature resistance, impact resistance, high hardness and flexural strength, as well as excellent electrical insulation and chemical stability, making it an ideal functional material. Experiments show that MgAl2O4 has certain radiation resistance properties and has long been used as a reactor wall material and a material for encapsulating nuclear waste. Therefore, developing laser materials based on MgAl2O4 could provide laser working materials for fields such as plasma diagnostics in large molten metal reactors, uranium isotope separation, space science research, and space communication. This invention prepares Cr3+-doped magnesium aluminum oxide nanopowder via a hydrothermal method. 3+ Magnesium oxide aluminum nano-precursor. The crystal phase is better formed by heat treatment in a solvothermal reactor. The reaction temperature, time, and pH value are adjusted to obtain nanoscale powder. The powder prepared by the method provided in this invention has advantages such as high purity, fine particle size, good sintering performance, and good luminescence properties. Furthermore, the preparation method is simple, has high production efficiency, and is suitable for industrial production.

[0060] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A type of Cr 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, include: Using magnesium nitrate, aluminum nitrate, and chromium nitrate as raw materials, according to MgAl 2-x O4:xCr 3+ According to the stoichiometric ratio, weigh out magnesium nitrate, aluminum nitrate and chromium nitrate respectively for later use; Magnesium nitrate, aluminum nitrate, and chromium nitrate were added to water and stirred until completely dissolved to obtain magnesium nitrate solution, aluminum nitrate solution, and chromium nitrate solution, respectively. Magnesium nitrate solution, aluminum nitrate solution and chromium nitrate solution are stirred together to prepare mixed solution one; Add ammonia water dropwise to mixed solution one until the pH value of mixed solution one is 3-9. Then stir and mix mixed solution one with added ammonia water to obtain mixed solution two. The mixed solution 2 was poured into a high-pressure reactor and placed in a constant temperature chamber to react, resulting in a white precipitate. Deionized water was added to the white precipitate to wash the precipitate, and the precipitate was obtained by centrifugation to obtain white precipitate powder. The white precipitate powder was dried at a constant temperature. The dried white precipitate powder was calcined to obtain nano-precursor powder.

2. The Cr as described in claim 1 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, Using magnesium nitrate, aluminum nitrate, and chromium nitrate as raw materials, according to MgAl 2-x O4:xCr 3+ In the step of weighing magnesium nitrate, aluminum nitrate, and chromium nitrate according to their stoichiometric ratios for later use... The raw materials used are magnesium nitrate, aluminum nitrate, and chromium nitrate with analytical purity standards.

3. The Cr as described in claim 2 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, In the step of preparing mixed solution one by stirring together magnesium nitrate solution, aluminum nitrate solution, and chromium nitrate solution,... The mixing time for magnesium nitrate solution, aluminum nitrate solution and chromium nitrate solution is 5-30 min, and the stirring rate is 500 r / min.

4. The Cr as described in claim 3 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, In the step of adding ammonia water dropwise to mixed solution one until the pH value of mixed solution one is 3-9, and then stirring the mixed solution one with added ammonia water to obtain mixed solution two,... The mixing time for adding ammonia water dropwise to the mixed solution is 10-40 minutes, and the stirring speed is 500 r / min.

5. The Cr as described in claim 4 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, In the step of pouring mixed solution II into a high-pressure reactor and placing it in a constant temperature chamber to react and obtain a white precipitate,... The reaction temperature of mixed solution 2 in the constant temperature chamber is 100-180℃.

6. The Cr as described in claim 5 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, In the step of pouring mixed solution II into a high-pressure reactor and placing it in a constant temperature chamber to react and obtain a white precipitate,... The reaction time of mixed solution 2 in the constant temperature incubator is 10-24 hours.

7. The Cr as described in claim 6 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, The specific steps for drying the white precipitate powder at a constant temperature include: The white precipitated powder was placed in a drying oven for constant temperature drying.

8. The Cr as described in claim 7 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, The specific steps for preparing nano-precursor powder by calcining the dried white precipitate powder include: The dried white precipitate powder was placed in a muffle furnace for calcination.

9. The Cr as described in claim 8 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, The step of calcining the dried white precipitate powder in a muffle furnace is described. The calcination temperature of the white precipitated powder is 600-1200℃.

10. The Cr as described in claim 9 3+ The method for synthesizing doped magnesium aluminum oxide nanopowder is characterized by, The step of calcining the dried white precipitate powder in a muffle furnace is described. The calcination time for white precipitated powder is 1-6 hours.

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