Preparation method of nitrogen-doped samarium borate powder

Abstract

The invention belongs to the technical field of inorganic material preparation, and particularly relates to a preparation method of nitrogen-doped samarium borate powder. According to the method, carbon black is used as a reducing agent to react with part of oxygen in samarium borate in a nitrogen atmosphere through a high-temperature sintering method to generate carbon monoxide, oxygen vacancies are filled with nitrogen atoms, nitrogen-doped samarium borate powder SmBO3-xNx is obtained, and x is larger than or equal to 0.03 and smaller than or equal to 0.27; the nitrogen element is introduced to reduce the phase transition temperature of samarium borate, and meanwhile, the energy band structure change and the surface plasma resonance effect enhancement are caused, so that the reflectivity is reduced, and the absorption performance is improved. Through testing of an ultraviolet, visible and near-infrared spectrophotometer, the nitrogen-doped samarium borate powder prepared by the method has strong absorption at the wavelength of 1.06 microns, the absorption performance is greatly improved compared with that of untreated powder, and the absorption performance of samarium borate in a laser wave band is improved, so that the nitrogen-doped samarium borate powder can be applied to a laser protection material.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic material preparation, and in particular relates to a method for preparing nitrogen-doped samarium borate powder. Background Art

[0002] Laser technology occupies a key position in the modern science and technology system due to its physical properties such as high energy density, excellent monochromaticity and coherence. Its application has deeply penetrated into cutting-edge fields such as precision medicine, high-speed optical communications, intelligent manufacturing and directed energy weapons, greatly promoting the innovation of human production, life and scientific research activities.

[0003] It is worth noting that with the development of laser technology, laser rangefinders, laser radars, etc. have long been successfully developed and equipped with various countries' troops and popularized to various civilian facilities. The throwing accuracy and combat capability of laser-guided missiles and bombs have reached an astonishing level. Laser protection technology mainly reduces the target's reflection signal of the laser to make the target low detectability. Its main starting point is to reduce the target's laser radar 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 geometric structure shape on the target laser scattering characteristics. The development of laser protection technology is inseparable from the development of new protective materials. At present, researchers are developing a new generation of high-efficiency and multifunctional protective materials in order to achieve better performance in absorbing, reflecting and scattering lasers. At the same time, with the help of emerging technologies such as artificial intelligence and big data, intelligent optimization and management of laser protection systems is also an important direction for the development of future protection technology. Finding a suitable and efficient laser absorption material is urgently needed.

[0004] Among them, rare earth Sm 3+ It has rich energy levels, which enables it to achieve energy level transition by absorbing photons. 6 H 5 / 2 Ground state 6 F 9 / 2 When the excited state undergoes transition, it can absorb light in the wavelength range of 1.05 to 1.15 μm, while the common laser transmitter works in the 1.06 μm band, which can absorb this band very well. Han Pengde and others first discovered samarium borate and conducted research on its application in the field of laser protection, but the laser absorption performance was not very ideal. Summary of the invention

[0005] In view of the above problems or shortcomings, in order to solve the problem that the existing samarium borate has poor laser absorption performance, the present invention provides a method for preparing nitrogen-doped samarium borate powder. The present invention uses carbon black as a reducing agent in a nitrogen atmosphere to react with part of the oxygen in the samarium borate to generate carbon monoxide through a high-temperature sintering method, so that nitrogen atoms fill oxygen vacancies, and finally obtain nitrogen-doped samarium borate powder, which improves the absorption performance of samarium borate in the laser band, so that it can be used in laser protection materials.

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

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

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

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

[0010] Step 4: Sinter the mixed powder C in a nitrogen atmosphere and grind it to obtain SmBO 3-x N x Nitrogen doped samarium borate powder, the chemical equation of the reaction is: SmBO3+C+N2→SmBO 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, and boron oxide is added in excess to avoid loss during preparation due to the low density of boron oxide, which makes the crystal form of the final product impure.

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

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

[0014] Furthermore, the protective gas in step 2 is nitrogen or argon, and the flow rate is 1 to 5 m 3 / h, the pressure in the furnace during sintering is 0.001-0.1MPa.

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

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

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

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

[0019] In summary, the present invention uses carbon black as a reducing agent to react with part of the oxygen in samarium borate to generate carbon monoxide in a nitrogen atmosphere through a high-temperature sintering method, so that nitrogen atoms fill oxygen vacancies to obtain nitrogen-doped samarium borate powder; the introduction of nitrogen elements is mainly used to reduce the phase transition temperature of samarium borate, while also causing changes in the energy band structure and enhancing the surface plasmon resonance effect, thereby reducing reflectivity and improving absorption performance. The SmBO prepared by the present invention is tested by an ultraviolet-visible-near-infrared spectrometer. 3-x N x Nitrogen-doped samarium borate powder has strong absorption at a wavelength of 1.06μm, which is much better than the absorption performance of untreated powder. It also improves the absorption performance of samarium borate in the laser band, so it can be used in laser protection materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the SEM image of the powder material prepared in Example 3.

[0021] Figure 2 The XPS spectra of the powder materials prepared in Examples 1 to 5. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the embodiments and 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 in that it comprises the following steps:

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

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

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

[0029] Step 4: Place the mixed powder C in a vacuum carbon tube furnace, evacuate to -0.1 MPa, then introduce nitrogen at a flow rate of 2 L / min. The pressure in the furnace is always maintained at 0.005 MPa. After heating at 1100 ° C for 2 h, take out and grind to obtain SmBO 3-x N x Nitrogen-doped samarium borate powder.

[0030] In the above embodiments, x is respectively set to 0.03, 0.09, 0.15, 0.21, and 0.27, corresponding to the tests to form 5 embodiments.

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

[0032] SmBO prepared in Examples 1 to 5 3-x N x The reflectivity of the laser band corresponding to the nitrogen-doped powder (the test method is to use the integrating sphere mode of the UV-visible near-infrared spectrophotometer to test the diffuse reflection) is shown in Table 1. As can be seen from Table 1, with the increase of the doping amount, the reflectivity of the laser band is gradually decreasing, indicating that the absorption performance of the powder is gradually enhanced, with the highest being 48.3% and the lowest being 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] It can be seen from the above specific implementation methods that the present invention uses a solid phase 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, and successfully achieving effective doping of nitrogen elements. This method reduces the crystal phase transition temperature of samarium borate and controls the product particle size within the micron range. The prepared nitrogen-doped samarium borate powder has good dispersibility, and the material's absorption rate within the laser wavelength range is significantly improved. The improvement in its laser absorption performance is mainly due to the change in the band structure caused by nitrogen doping and the enhancement of the surface plasmon resonance effect. This new 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: The following steps are involved: Step 1: Grind samarium oxide and boron oxide at a molar ratio of 1:1 and mix well to obtain mixed powder A; Step 2: Sintering the mixed powder A in a protective gas atmosphere to obtain SmBO3 powder B; Step 3: Grind carbon black and SmBO3 powder B at a molar ratio of x:1 to obtain mixed powder C, 0.03≤x≤0.27; Step 4: Sinter the mixed powder C in a nitrogen atmosphere and grind it to obtain SmBO 3-x N x Nitrogen doped samarium borate powder, the chemical equation of the reaction is: SmBO3+C+N2→SmBO 3-x N x +CO.

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

3. The method for preparing nitrogen-doped samarium borate powder according to claim 1, characterized in that: The sintering equipment in step 2 is a vacuum carbon tube furnace or a vacuum muffle furnace, the sintering temperature is 900-1300° C., the heating rate is 5-15° C. / min, and the insulation time is 2-4h.

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

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

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

7. The method for preparing nitrogen-doped samarium borate powder according to claim 1, characterized in that: The sintering equipment in step 4 is a vacuum carbon tube furnace or a vacuum muffle furnace, the sintering temperature is 900-1300° C., the heating rate is 5-15° C. / min, and the insulation time is 2-4h.

8. The method for preparing nitrogen-doped samarium borate powder according to claim 1, characterized in that: In the step 1, samarium oxide and boron oxide are ground and mixed at a molar ratio of 1:1-2, and boron oxide is added in excess to avoid loss during preparation due to the low density of boron oxide, which makes the crystal form of the final product impure.

9. A nitrogen-doped samarium borate powder, characterized in that: The material is prepared by the preparation method described in any one of claims 1 to 8 and is applied to laser protection materials.

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