A method for preparing nitrogen-doped samarium borate powder

Abstract

This invention belongs to the field of inorganic material preparation technology, specifically relating to a method for preparing nitrogen-doped samarium borate powder. The invention utilizes a high-temperature sintering method in a nitrogen atmosphere, employing carbon black as a reducing agent to react with some oxygen in samarium borate to generate carbon monoxide, thereby filling oxygen vacancies with nitrogen atoms to obtain nitrogen-doped samarium borate powder (SmBO). 3‑x N x The formula is 0.03≤x≤0.27. The main advantage lies in the introduction of nitrogen to lower the phase transition temperature of samarium borate, which also alters the band structure and enhances surface plasmon resonance, thereby reducing reflectivity and improving absorption performance. Spectrophotometer tests using UV-Vis-NIR spectrophotometers show that the nitrogen-doped samarium borate powder prepared in this invention exhibits strong absorption at a wavelength of 1.06 μm, significantly improving absorption performance compared to untreated powder. This enhances the absorption performance of samarium borate in the laser band, making it suitable for use in laser protection materials.

Description

Technical Field

[0001] This invention belongs to the field of inorganic material preparation technology, specifically relating to a method for preparing nitrogen-doped samarium borate powder. Background Technology

[0002] Laser technology, with its high energy density, excellent monochromaticity, and coherence, occupies a crucial position in the modern technological system. Its applications have deeply penetrated cutting-edge fields such as precision medicine, high-speed optical communication, intelligent manufacturing, and directed-energy weapons, greatly promoting innovation in human production, life, and scientific research.

[0003] It is worth noting that with the development of laser technology, laser rangefinders and lidar have long been successfully developed and equipped by the armed forces of various countries and widely used in various civilian facilities. The delivery accuracy and combat capability of laser-guided missiles and bombs have reached an astonishing level. Laser protection technology mainly reduces the target's reflective signal to the laser, making the target less detectable. Its main starting point is to reduce the target's lidar scattering cross section (LRCS) and laser reflectivity. LRCS comprehensively reflects the influence of various factors such as laser wavelength, target surface material and roughness, and target geometry on the target's laser scattering characteristics. The development of laser protection technology is inseparable from the development of new protective materials. Currently, researchers are developing a new generation of high-efficiency, multi-functional protective materials, aiming to achieve better performance in absorbing, reflecting, and scattering lasers. At the same time, using emerging technologies such as artificial intelligence and big data to intelligently optimize and manage laser protection systems is also an important direction for the future development of protection technology. Finding a suitable and efficient laser absorbing material is urgently needed.

[0004] Among them, rare earth Sm 3+ It possesses abundant energy levels, enabling it to achieve energy level transitions by absorbing photons. 6 H 5 / 2 ground state to 6 F 9 / 2 When the excited state undergoes a transition, it can absorb light in the wavelength range of 1.05–1.15 μm, while the operating wavelength of common laser emitters is 1.06 μm, which can effectively absorb this wavelength. Han Pengde et al. first discovered samarium borate and conducted research on its application in the field of laser protection, but its laser absorption performance was not ideal. Summary of the Invention

[0005] To address the aforementioned problems and shortcomings, and to overcome the poor laser absorption performance of existing samarium borate, this invention provides a method for preparing nitrogen-doped samarium borate powder. This invention utilizes a high-temperature sintering method in a nitrogen atmosphere, employing carbon black as a reducing agent to react with some of the oxygen in samarium borate to generate carbon monoxide. This allows nitrogen atoms to fill oxygen vacancies, ultimately yielding nitrogen-doped samarium borate powder. This improves the absorption performance of samarium borate in the laser band, thus enabling its application in laser protection materials.

[0006] A method for preparing nitrogen-doped samarium borate powder, using a solid-state reaction method, includes the following steps:

[0007] Step 1: Grind samarium oxide and boron oxide in a molar ratio of 1:1 to obtain mixed powder A.

[0008] Step 2: Sinter the mixed powder A in a protective atmosphere to obtain SmBO3 powder B.

[0009] Step 3: Grind carbon black and SmBO3 powder B in a molar ratio of x:1 to obtain mixed powder C, where 0.03≤x≤0.27.

[0010] Step 4: Sinter the mixed powder C in a nitrogen atmosphere and then grind it to obtain SmBO. 3-x N x The chemical equation for the reaction of nitrogen-doped samarium borate powder is: SmBO3 + C + N2 → SmBO3 3-x N x +CO.

[0011] Furthermore, in step 1, samarium oxide and boron oxide are ground and mixed in a molar ratio of 1:1-2. Boron oxide is added in excess to avoid loss during preparation due to its low density, which would result in an impure crystal form of the final product.

[0012] Furthermore, the grinding method in step 1 is to grind with a mortar and pestle for 10-30 minutes or to ball mill with a planetary ball mill for 6-24 hours.

[0013] Furthermore, the sintering equipment in step 2 is a vacuum carbon tube furnace or a vacuum muffle furnace, with a sintering temperature of 900-1300℃, a heating rate of 5-15℃ / min, and a holding time of 2-4h.

[0014] Furthermore, the protective gas in step 2 is nitrogen or argon, with a flow rate of 1–5 m³ / h. 3 / h, the pressure in the furnace body during sintering is 0.001-0.1MPa.

[0015] Furthermore, the grinding method in step 3 is to grind in a mortar for 10-30 minutes.

[0016] Furthermore, the nitrogen flow rate in step 4 is 1–5 m³ / h. 3 / h, the pressure in the furnace body is 0.001-0.1MPa.

[0017] Furthermore, the sintering equipment in step 4 is a vacuum carbon tube furnace or a vacuum muffle furnace, with a sintering temperature of 900-1300℃, a heating rate of 5-15℃ / min, and a holding time of 2-4h.

[0018] Furthermore, the nitrogen-doped samarium borate powder prepared by the above method exhibits strong absorption at a wavelength of 1.06 μm, and can be applied to laser protection materials.

[0019] In summary, this invention utilizes a high-temperature sintering method in a nitrogen atmosphere to react carbon black as a reducing agent with some oxygen in samarium borate to generate carbon monoxide, allowing nitrogen atoms to fill oxygen vacancies and obtaining nitrogen-doped samarium borate powder. The main advantage lies in the introduction of nitrogen to lower the phase transition temperature of samarium borate, while also inducing changes in the band structure and enhanced surface plasmon resonance effect, thereby reducing reflectivity and improving absorption performance. Measurements using a UV-Vis-NIR spectrophotometer show that the SmBO powder prepared in this invention... 3-x N x Nitrogen-doped samarium borate powder exhibits strong absorption at a wavelength of 1.06 μm, which is a significant improvement over untreated powder. This enhances the absorption performance of samarium borate in the laser band, making it suitable for use in laser protection materials. Attached Figure Description

[0020] Figure 1 The image shows an SEM image of the powder material prepared in Example 3.

[0021] Figure 2 XPS spectra of the powder materials prepared in Examples 1-5. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0023] The following examples all use commercially available samarium oxide, boron oxide and carbon black powders with a purity greater than 99.9% as raw materials.

[0024] Example

[0025] A method for preparing nitrogen-doped samarium borate powder, characterized by comprising the following steps:

[0026] Step 1: Weigh samarium oxide and boron oxide according to the stoichiometric ratio of the SmBO3 chemical formula, put them into a mortar, and grind them at room temperature for 20 minutes to obtain mixed powder A.

[0027] Step 2: Place the mixed powder A into a vacuum carbon tube furnace, evacuate to -0.1 MPa, and then introduce argon protective gas at a flow rate of 2 L / min. The pressure inside the furnace is always maintained at 0.005 MPa. After heating at 1100℃ for 2 hours, remove and grind to obtain samarium borate powder B.

[0028] Step 3, according to the chemical formula SmBO 3-x N x The samarium borate powder B and carbon black were weighed in stoichiometric ratio, placed in a mortar, and ground at room temperature for 20 minutes to obtain mixed powder C.

[0029] Step 4: Place the above mixed powder C into a vacuum carbon tube furnace, evacuate to -0.1 MPa, then introduce nitrogen gas at a flow rate of 2 L / min, maintaining the furnace pressure at 0.005 MPa throughout. Heat at 1100℃ for 2 hours, then remove and grind to obtain SmBO. 3-x N x Nitrogen-doped samarium borate powder.

[0030] In the above embodiments, x is taken as 0.03, 0.09, 0.15, 0.21, and 0.27 respectively, corresponding to the tests that constitute 5 embodiments.

[0031] The SEM image of the nitrogen-doped sample prepared in Example 3 is as follows: Figure 1 As shown. By Figure 1 As can be seen, the sample surface contains some fine particles with a particle size distribution of 2-10 μm. The XPS spectra of the nitrogen-doped powders prepared in Examples 1-5 are shown below. Figure 2 As shown. By Figure 2 The presence of nitrogen peaks further proves that nitrogen atoms have been successfully doped into the crystal lattice.

[0032] SmBO prepared in Examples 1-5 3-x N x The reflectance of nitrogen-doped powder in the corresponding laser band (tested using an integrating sphere mode of a UV-Vis-NIR spectrophotometer for diffuse reflectance) is shown in Table 1 below. As can be seen from Table 1, the reflectance in the laser band gradually decreases with increasing doping concentration, indicating that the powder's absorption performance gradually increases, reaching a maximum of 48.3% and a minimum of 16.2%.

[0033] Table 1:

[0034] Example Chemical formula Laser reflectivity / % 1 <![CDATA[SmBO 2.97 N 0.03 ]]> 48.3％ 2 <![CDATA[SmBO 2.91 N 0.09 ]]> 40.6％ 3 <![CDATA[SmBO 2.85 N 0.15 ]]> 34.7％ 4 <![CDATA[SmBO 2.79 N 0.21 ]]> 22.9％ 5 <![CDATA[SmBO 2.73 N 0.27 ]]> 16.2％

[0035] As can be seen from the above specific implementation methods, this invention employs a solid-state reaction method to modify the structure of samarium borate powder. Specifically, by reacting carbon black with samarium borate powder at high temperature in a nitrogen atmosphere, effective nitrogen doping is successfully achieved. This method lowers the crystal phase transition temperature of samarium borate and controls the product particle size within the micrometer range. The prepared nitrogen-doped samarium borate powder exhibits good dispersibility, and the material's absorption rate within the laser wavelength range is significantly improved. The enhanced laser absorption performance is mainly due to the change in band structure and enhanced surface plasmon resonance effect caused by nitrogen doping. This novel powder material is particularly suitable for optoelectronic protection fields such as high-power laser protective coatings and optical limiting devices.

Claims

1. A method for preparing nitrogen-doped samarium borate powder, characterized in that, Includes the following steps: Step 1: Grind and mix samarium oxide and boron oxide in a molar ratio of 1:1-2 to obtain mixed powder A; Step 2: Sinter the mixed powder A in a protective atmosphere to obtain SmBO3 powder B; Step 3: Grind carbon black and SmBO3 powder B in a molar ratio of x:1 to obtain mixed powder C, where 0.03 ≤ x ≤ 0.27; Step 4: Sinter the mixed powder C in a nitrogen atmosphere and then grind it to obtain SmBO. 3-x N x The chemical equation for the reaction of nitrogen-doped samarium borate powder is: SmBO3 + C + N2 → SmBO3 3-x N x +CO.

2. The method for preparing nitrogen-doped samarium borate powder as described in claim 1, characterized in that: The grinding method in step 1 is to grind with a mortar and pestle for 10-30 minutes or to ball mill with a planetary ball mill for 6-24 hours.

3. The method for preparing nitrogen-doped samarium borate powder as described in claim 1, characterized in that: The sintering equipment in step 2 is a vacuum carbon tube furnace or a vacuum muffle furnace, with a sintering temperature of 900-1300℃, a heating rate of 5-15℃ / min, and a holding time of 2-4h.

4. The method for preparing nitrogen-doped samarium borate powder as described in claim 1, characterized in that: The protective gas in step 2 is nitrogen or argon, with a flow rate of 1–5 m³ / h. 3 / h, the pressure in the furnace body during sintering is 0.001-0.01MPa.

5. The method for preparing nitrogen-doped samarium borate powder as described in claim 1, characterized in that: The grinding method in step 3 is to grind in a mortar for 10-30 minutes.

6. The method for preparing nitrogen-doped samarium borate powder as described in claim 1, characterized in that: In step 4, the nitrogen flow rate is 1-5 m³ / h. 3 / h, the pressure in the furnace body is 0.001-0.01MPa.

7. The method for preparing nitrogen-doped samarium borate powder as described in claim 1, characterized in that: The sintering equipment in step 4 is a vacuum carbon tube furnace or a vacuum muffle furnace, with a sintering temperature of 900-1300℃, a heating rate of 5-15℃ / min, and a holding time of 2-4h.

8. A nitrogen-doped samarium borate powder, characterized in that: It is prepared by any of the preparation methods described in claims 1-7 and applied to laser protection materials.

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