CN110615807B - Rare earth metal organic complex wave-absorbing material and preparation method thereof - Google Patents
Rare earth metal organic complex wave-absorbing material and preparation method thereof Download PDFInfo
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- CN110615807B CN110615807B CN201910985768.1A CN201910985768A CN110615807B CN 110615807 B CN110615807 B CN 110615807B CN 201910985768 A CN201910985768 A CN 201910985768A CN 110615807 B CN110615807 B CN 110615807B
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Abstract
The invention relates to a rare earth metal organic complex wave-absorbing material. The wave-absorbing material is a mononuclear complex single crystal formed by coordination of rare earth metal salt and maleic dihydrazide. Compared with the prior art, the rare earth metal organic complex wave-absorbing material can reach-48.832 dB maximum reflection loss without high-temperature carbonization, accords with the mainstream social consciousness of energy conservation and emission reduction of the current society, has higher safety factor and simple material preparation process, and is easy for industrial production.
Description
[ technical field ] A method for producing a semiconductor device
The invention belongs to the technical field of wave-absorbing materials. More specifically, the invention relates to a rare earth metal organic complex wave-absorbing material and a preparation method thereof.
[ background of the invention ]
With the change of science and technology, people are increasingly surrounded by various electromagnetic waves. In modern people's daily life, electrical appliances such as television signal towers, common microwave ovens, televisions, computers, mobile phones, various chargers and the like are constantly emitting electromagnetic waves to people. These electromagnetic waves pose potential threats to people's health and safety in production. Compared with light pollution, water pollution and chemical pollution, the electromagnetic wave pollution has wider harm to human beings and is easier to be ignored by people. Therefore, the prevention and treatment of electromagnetic wave pollution is more urgent and important. In the military field, stealth performance becomes the most important performance index of a new generation of ships and airplanes (American standard). The wave-absorbing coating determines the performance of stealth military equipment and becomes the key of stealth performance technology. Therefore, the wave-absorbing material research leads the development of stealth technology. The mechanism of absorbing electromagnetic waves by the wave-absorbing material is mainly divided into two types, one of which is electromagnetic loss. The material forms a magnetic field opposite to an external magnetic field through an induced current formed between closed areas, thereby preventing electromagnetic waves from being incident. Secondly, after the electromagnetic wave is incident on the material, the electromagnetic wave is attenuated and weakened in the material and is converted into energy in other forms.
The excellent wave-absorbing material has the characteristics of wide, thin, light, strong and the like. However, the conventional wave-absorbing materials, such as ferrite and ceramic wave-absorbing materials, have the disadvantages of narrow effective absorption band, too high material density, too low absorption strength, and the like. Therefore, the research on novel wave-absorbing materials is very meaningful work. Metal organic frame material as a novel polyThe porous material has the characteristics of good conductivity, light weight, small density, large specific surface area, porosity and the like. The metal-organic framework has a very high porosity and a particularly large specific surface area (up to 1000m in some cases)2/g) to make it a very potential functional material. In recent years, it has been used as an absorption of electromagnetic waves by researchers at home and abroad, and a great progress has been made. In addition, the metal organic framework material has magnetic central metal ions, so that the whole metal organic framework material has good magnetism. The adsorption performance of the metal organic framework material and the derivative material thereof on electromagnetic waves caused by the adsorption performance of the metal organic framework material and the derivative material thereof are more attractive in the research of wave-absorbing materials. Metal organic frameworks are often carbonized at high temperature to prepare wave-absorbing materials, which are reported in NannanWu, Dongmei Xu, ZhouWang, et al, academic super electron wave absorbers through the novel metal-organic framework derived from magnetic porous Carbon nanoparticles, Carbon,2019, (145): 433-. However, when the metal organic frame material is carbonized at high temperature, a large amount of energy is wasted, and secondly, the high temperature of hundreds or even thousands of degrees centigrade brings great potential safety hazard to the industrial production. Compared with the carbonization method, in 2018, m.green et al (m.green a, z.liu b, p.xiang c, et al, ferromagnetic metal-organic frame for microwave absorption. materials Today Chemistry 2018, (9)140-148) of the united states University of missouri Kansas City assembled a metal-organic framework using Ferric nitrate and 2,3,4, 5-tetramethylterephthalic acid, and was first confirmed to have superior wave absorbing properties. The maximum reflection loss of the prepared material is-54.2 dB, and the work opens up a precedent that the metal organic framework is directly applied to the electromagnetic wave absorption material. The Green method directly applies a suitable metal organic framework material to the preparation of the wave-absorbing material, is more in line with the current mainstream social value view, and is more suitable for industrialization.
However, iron ions have fewer coordination sites, which makes coordination difficult. Compared with the central atomic iron of the iron-metal organic framework material, the lanthanide metal ions have the characteristics of oxygen affinity, nitrogen affinity and the like, and have unique 4f orbital electrons, so that the lanthanide metal ions have rich, unique and novel topological structures when forming the metal organic framework. Thereby bringing wide application prospect. Since Wilkinson (Roume, Mawy column, Suqingde, metallocene-type rare earth metal organic complex) synthesized and characterized research progressed in 1954, structural chemistry 2003, 22(1):7-16) synthesized rare earth metal organic compounds for the first time, metal organic frameworks of tens of thousands of lanthanide metals have been synthesized.
According to the current literature, no report that the metal organic framework material coordinated by rare earth metal is directly used for preparing the wave-absorbing material is found. Aiming at the technical defects in the prior art, the inventor finally completes the invention through a large number of experimental researches and analytical summarization on the basis of summarizing the prior art.
[ summary of the invention ]
[ problem to be solved ]
The invention aims to provide a rare earth metal organic complex wave-absorbing material.
The invention also aims to provide a preparation method of the rare earth metal organic complex wave-absorbing material.
[ solution ]
The invention is realized by the following technical scheme.
The invention relates to a rare earth metal organic complex wave-absorbing material.
The wave-absorbing material is a mononuclear complex single crystal consisting of praseodymium rare earth metal ions and maleic dihydrazide ligands, and the three-dimensional structural formula of the wave-absorbing material is as follows:
in the formula:
pr1A and Pr1B represent metal ions Pr (III) involved in coordination; N3-N6 respectively represent nitrogen atoms of maleic dihydrazide molecules which do not participate in coordination; N2A-N2B respectively represent nitrogen atoms which participate in coordination and do not participate in coordination in the maleic dihydrazide molecule; N1A-N1B respectively represent nitrogen atoms which participate in coordination and do not participate in coordination in the maleic dihydrazide molecule; O1A-O6A respectively represent oxygen atoms which participate in coordination of the maleic dihydrazide; O1B-O6B respectively represent oxygen atoms which participate in coordination of the maleic dihydrazide; O1C-O6C respectively represent oxygen atoms participating in coordination in a maleic dihydrazide molecule; O1D-O6D respectively represent oxygen atoms participating in coordination in a maleic dihydrazide molecule;
unit cell parameters: 17.6539(15), 13.148(11), 14.0261 (12);
the wave absorbing performance is as follows: the wave-absorbing material has reflection loss below-10 dB when the thickness reaches 2.5 mm. The maximum reflection loss is-48.832 dB when the thickness is 5.5 mm.
According to a preferred embodiment of the present invention, the praseodymium rare earth metal is replaced by a lanthanum, cerium, neodymium or scandium rare earth metal.
The invention also relates to a preparation method of the rare earth metal organic complex wave-absorbing material.
The preparation method comprises the following steps:
A. preparation of the mixture solution
Carrying out ultrasonic dissolution on rare earth metal salt and maleic dihydrazide in a solvent according to a molar ratio of 1: 1.5-4.5 to obtain a mixture solution;
B. heat treatment of
Heating the mixture solution obtained in the step A in an oven at a uniform heating speed to 150-190 ℃, and carrying out heat preservation treatment at the temperature for 24-72 h;
C. washing machine
Cooling the mixture solution heated in the step B to room temperature at a cooling speed of 2-10 ℃/h, filtering, washing filter residues with washing liquor, and collecting solid particles of the rare earth metal organic complex;
D. soaking
C, soaking the rare earth metal organic complex obtained in the step C in DMF at room temperature according to the volume ratio of the rare earth metal organic complex to DMF of 1: 2-5, and replacing DMF once every 12 hours of soaking; then, according to the volume ratio of the rare earth metal organic complex to acetone of 1: 2-5, soaking the rare earth metal organic complex soaked in DMF in acetone at room temperature, and replacing new acetone once every 12 hours of soaking;
E. thermal treatment
And activating the soaked rare earth metal organic complex at the temperature of 140-160 ℃ for 1-8 h, and grinding into powder to obtain the wave-absorbing material.
According to a preferred embodiment of the present invention, in step a, the rare earth metal salt is a rare earth metal salt of praseodymium nitrate hexahydrate, lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, neodymium nitrate hexahydrate, scandium chloride, lanthanum chloride, cerium chloride, neodymium chloride, scandium sulfate, lanthanum sulfate, cerium sulfate, or neodymium sulfate.
According to another preferred embodiment of the present invention, in step a, the solvent is DMF, ethanol or water.
According to a preferred embodiment of the present invention, in the step A, the ultrasonic dissolution is performed at an ultrasonic frequency of 20 to 40kHz and a power density of 0.3 to 0.35W/cm2Dissolving for 25-35 min under the condition (1).
According to a preferred embodiment of the present invention, in the step B, the uniform heating rate is 10 to 15 ℃/min.
According to a preferred embodiment of the present invention, in step C, the residue is treated with DMF, ethanol or an aqueous solvent in a volume ratio of the residue to the solvent of 1: 2-4 washing for 2-5 times.
According to a preferred embodiment of the invention, in the step D, the rare earth metal organic complex obtained in the step C is soaked in DMF for 12-72 h; and then the solvent acetone is replaced to continuously soak for 12-72 h.
According to a preferred embodiment of the invention, in the step D, the particle size of the powdery wave-absorbing material is 150-300 meshes.
The present invention will be described in more detail below.
The invention relates to a rare earth metal organic complex wave-absorbing material.
The wave-absorbing material is a mononuclear complex single crystal consisting of praseodymium rare earth metal ions and maleic dihydrazide ligands, and the three-dimensional structural formula of the wave-absorbing material is as follows:
in the figure:
pr1A and Pr1B represent metal ions Pr (III) involved in coordination; N3-N6 respectively represent nitrogen atoms of maleic dihydrazide molecules which do not participate in coordination; N2A-N2B respectively represent nitrogen atoms which participate in coordination and do not participate in coordination in the maleic dihydrazide molecule; N1A-N1B respectively represent nitrogen atoms which participate in coordination and do not participate in coordination in the maleic dihydrazide molecule; O1A-O6A respectively represent oxygen atoms which participate in coordination of the maleic dihydrazide; O1B-O6B respectively represent oxygen atoms which participate in coordination of maleic dihydrazide; O1C-O6C respectively represent oxygen atoms participating in coordination in a maleic dihydrazide molecule; O1D-O6D respectively represent oxygen atoms participating in coordination in a maleic dihydrazide molecule;
unit cell parameters: 17.6539(15), 13.148(11), 14.0261 (12);
the rare earth metal organic complex wave-absorbing material of the present invention was subjected to X-ray diffraction analysis according to a conventional analysis method using an X-ray diffraction analyzer sold under the trade name D8 Venture X by Bruker, Germany, and the results thereof are shown in FIG. 1. The ligands and the metal ions are respectively simplified into nodes, topology analysis is carried out on the nodes, and the topological structure analysis result is shown in the attached figure 2. The results shown in the attached figure 1 calculate the cell parameters of the rare earth metal organic complex wave-absorbing material according to diffraction data as follows:
17.6539(15), 13.148(11), 14.0261 (12); wherein the data in parentheses is the error parameter of the last significant digit;
and the above-mentioned three-dimensional structural formula is deduced from the results of X-ray diffraction analysis.
The wave absorbing performance of the rare earth metal organic complex wave absorbing material is determined according to a coaxial law strip: the electromagnetic wave absorption performance of the wave absorbing material is measured by using an Agilent E8363B vector network analyzer:
the wave-absorbing material has reflection loss below-10 dB when the thickness reaches 2.5 mm; the maximum reflection loss is-48.832 dB when the thickness is 5.5 mm.
The rare earth metal salt used in the present invention is praseodymium nitrate hexahydrate, lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, neodymium nitrate hexahydrate, scandium chloride, lanthanum chloride, cerium chloride, neodymium chloride, scandium sulfate, lanthanum sulfate, cerium sulfate or neodymium sulfate rare earth metal salt, which are all products currently sold in the market, such as praseodymium nitrate hexahydrate sold by the company alatin, cerium chloride sold by the company national medicine, and neodymium sulfate sold by the company sigma. Of course, other rare earth metals besides the rare earth metals can be used in the invention, but they do not have negative influence on the wave-absorbing material of the invention, so that these rare earth metals are all within the protection scope of the invention.
The invention also relates to a preparation method of the rare earth metal organic complex wave-absorbing material.
The preparation method comprises the following steps:
A. preparation of the mixture solution
Carrying out ultrasonic dissolution on rare earth metal salt and maleic dihydrazide in a solvent according to a molar ratio of 1: 1.5-4.5 to obtain a mixture solution;
in the invention, the main function of the rare earth metal salt in the rare earth metal organic complex wave-absorbing material is to coordinate with maleic dihydrazide to form a metal organic framework material;
in the present invention, the metal-organic complex and the metal-organic framework material have the same meaning and may be used interchangeably.
The maleic dihydrazide mainly plays a role in the rare earth metal organic complex wave-absorbing material as an organic ligand to participate in coordination to form a metal organic framework material;
according to the invention, the molar ratio of the rare earth metal salt to the maleic dihydrazide is 1: 1.5-4.5. If the molar ratio of the rare earth metal salt to the maleic dihydrazide is more than 1:1.5, a complex single crystal cannot be formed; if the molar ratio of the rare earth metal salt to the maleic dihydrazide is less than 1:4.5, a mononuclear single crystal in which the maleic dihydrazide is coordinated with the rare earth metal cannot be formed; therefore, a molar ratio of the rare earth metal salt to the maleic dihydrazide of 1: 1.5-4.5 is reasonable, preferably 1: 1.8-4.2, and more preferably 1: 2.0-3.0.
The rare earth metal salt used in the invention is rare earth metal salt of praseodymium nitrate hexahydrate, lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, neodymium nitrate hexahydrate, scandium chloride, lanthanum chloride, cerium chloride, neodymium chloride, scandium sulfate, lanthanum sulfate, cerium sulfate or neodymium sulfate. The rare earth metal salt has already been described above and will not be described in detail. The maleic dihydrazide used in the present invention is a product currently marketed, for example, as analytically pure maleic dihydrazide marketed by the company Aladdin.
In this step, the solvent has a basic function of dissolving the reaction raw material. According to the invention, the solvent is DMF (dimethylformamide), ethanol or water. The ratio of the rare earth metal salt in grams to the solvent in milliliters is 1: 4-8.
The basic effect of ultrasonic dissolution in this step is to accelerate the dissolution rate and to promote the catalytic reaction. The ultrasonic dissolution is carried out at the ultrasonic frequency of 20-40 kHz and the power density of 0.3-0.35W/cm2Dissolving for 25-35 min under the condition (1). In the invention, ultrasonic frequency, power density and ultrasonic time exceed the ranges are not preferable, because the ultrasonic power is too high, the reaction system is separated out, the raw material is partially dissolved if the ultrasonic power is too low, the time cost is wasted if the ultrasonic power is too long, the raw material is not dissolved if the ultrasonic power is too short, the raw material is separated out if the ultrasonic frequency is too high, and the preliminary catalytic reaction cannot be carried out if the ultrasonic frequency is too low.
The ultrasonic equipment used by the invention is a product sold in the market at present, such as a Union YM-040S product sold by Aurea Limited company in Shenzhen.
B. Heat treatment of
Heating the mixture solution obtained in the step A in an oven at a uniform heating speed to 150-190 ℃, and carrying out heat preservation treatment at the temperature for 24-72 h;
in this step, the reason why the heating rate is kept uniform in heating is mainly to make the reaction proceed uniformly. The uniform heating speed is 10-15 ℃/min. If the uniform heating rate is lower than 10 ℃/min, the heating time is too long, so that the whole reaction time is too long; if the uniform heating speed is higher than 15 ℃/min, the heating speed is too high, so that the reaction is insufficient and uneven; therefore, the uniform heating speed is proper to be 10-15 ℃/min;
in the step, the mixture solution obtained in the step A is heated to 150-190 ℃. If the mixture solution is heated to be lower than 150 ℃, the reaction can not be carried out; heating the mixture solution to be higher than 190 ℃, and then violently decomposing the solvent to ensure that the reaction system can not obtain the complex; therefore, the heating temperature of the mixture solution is suitably 150 to 190 ℃;
in this step, the basic purpose of the incubation treatment is to improve the reaction efficiency. The time of the heat preservation treatment is less than 24 hours, the yield of the product is very low; if the heat preservation treatment time is longer than 72h, the reaction time is prolonged, and the cost is wasted; therefore, the heat preservation treatment time is suitably 24 to 72 hours, preferably 30 to 60 hours, and more preferably 38 to 50 hours.
C. Washing machine
Cooling the mixture solution heated in the step B to room temperature at a cooling speed of 2-10 ℃/h, filtering, washing filter residues with washing liquor, and collecting the rare earth metal organic complex;
in this step, the essential purpose of cooling the mixture solution to room temperature is to precipitate the product of the reaction system which has been complexed in the form of a single crystal.
The equipment used in the filtration is currently marketed filtration equipment, such as a Chengda brand strainer spoon. The filtering device can remove irregular powder solid and keep the complete rare earth metal organic complex.
In this step, the filter residue is treated with DMF, ethanol or aqueous solvent according to a volume ratio of filter residue to solvent of 1: 2-4 washing for 2-5 times.
D. Soaking
C, soaking the rare earth metal organic complex obtained in the step C in DMF at room temperature according to the volume ratio of the rare earth metal organic complex to DMF of 1: 2-5, and replacing DMF once every 12 hours of soaking; then, according to the volume ratio of the rare earth metal organic complex to acetone of 1: 2-5, soaking the rare earth metal organic complex soaked in DMF in acetone at room temperature, and replacing new acetone once every 12 hours of soaking;
according to the invention, the rare earth metal organic complex obtained in the step C is soaked in DMF for 12-72 h; the rare earth metal organic complex is soaked in DMF mainly for removing the raw material which is not reacted and is adsorbed on the surface of the crystal. The volume ratio of the rare earth metal organic complex to DMF is 1: 2-5. If the volume ratio of the rare earth metal organic complex to DMF is more than 1:2, raw materials are not easy to remove; if the volume ratio of the rare earth metal organic complex to DMF is less than 1:5, dissolving the product; therefore, the volume ratio of the rare earth metal organic complex to DMF is proper to be 1: 2-5, and preferably 1: 3-4;
if the soaking time of the rare earth metal organic complex in DMF is less than 12h, the rare earth metal organic complex can not be completely removed; if the soaking time of the rare earth metal organic complex in DMF is longer than 72h, the product collapses or dissolves; therefore, the soaking time of the rare earth metal organic complex in DMF is suitable to be 12-72 h, and preferably 22-52 h;
and (3) soaking the rare earth metal organic complex soaked in the DMF in acetone for 12-72 h. The subsequent immersion of the organic complexes of rare earth metals in DMF in acetone is mainly to exchange the small guest molecules in the framework pores. The volume ratio of the rare earth metal organic complex to acetone is 1: 2-5. If the volume ratio of the rare earth metal organic complex to acetone is more than 1:2, complete exchange is not easy to occur; if the volume ratio of the rare earth metal organic complex to the acetone is less than 1:5, the acetone is seriously wasted; therefore, the volume ratio of the rare earth metal organic complex to the acetone is proper to be 1: 2-5, and preferably 1: 3-4;
if the soaking time of the rare earth metal organic complex soaked in the DMF in acetone is less than 12 hours, raw materials cannot be completely dissolved or small molecules cannot be exchanged; if the rare earth metal organic complex soaked in DMF is soaked in acetone for longer than 72h, collapse and dissolution occur; therefore, the soaking time of the rare earth metal organic complex soaked in the DMF in acetone is suitable to be 12-72 h, and preferably 22-52 h;
E. thermal treatment
And activating the soaked rare earth metal organic complex at the temperature of 140-160 ℃ for 1-8 h, and grinding into powder to obtain the wave-absorbing material.
In the present invention, this activation treatment is intended to remove residual acetone remaining in the frame holes.
In the invention, when the activation treatment is 1-8 h, if the temperature of the activation treatment is lower than 140 ℃, acetone cannot be completely removed; if the temperature of the activation treatment is higher than 160 ℃, the framework structure is damaged; therefore, the temperature of the activation treatment is reasonable to be 140-160 ℃; preferably 146 to 154 ℃.
According to the invention, the granularity of the powdery wave-absorbing material is 150-300 meshes.
The prepared maleic dihydrazide and praseodymium coordination polymer product is analyzed and identified by adopting the method described above, is a monoclinic crystal form,
unit cell parameters: 17.6539(15), 13.148(11), 14.0261 (12);
the wave absorbing performance is as follows: the wave-absorbing material has reflection loss below-10 dB when the thickness reaches 2.5 mm. The maximum reflection loss is-48.832 dB when the thickness is 5.5 mm.
[ advantageous effects ]
The invention has the beneficial effects that: compared with the prior art, the rare earth metal organic complex wave-absorbing material can achieve the wave-absorbing performance with the maximum reflection loss of-48.832 dB without high-temperature carbonization, accords with the mainstream social consciousness of energy conservation and emission reduction in the current society, has higher safety factor and simple preparation process, and is easy for industrial production.
[ description of the drawings ]
FIG. 1 is a crystal coordination environment diagram of maleic dihydrazide and praseodymium nitrate hexahydrate metal organic complex;
FIG. 2 is a crystal topology diagram of a maleic dihydrazide and praseodymium nitrate hexahydrate metal organic complex;
FIG. 3 is a graph of the electromagnetic wave absorption performance of the crystals of the metal-organic complex prepared in example 1 at different thicknesses;
FIG. 4 is a graph of the electromagnetic wave absorption performance of the metal-organic complex crystals with different thicknesses prepared in example 2;
FIG. 5 is a graph of electromagnetic wave absorption performance of organometallic complex crystals with different thicknesses prepared in example 3.
FIG. 6 is a graph of electromagnetic wave absorption performance of organometallic complex crystals with different thicknesses prepared in example 4.
[ detailed description ] embodiments
The invention will be better understood from the following examples.
Example 1: preparation of rare earth metal organic complex wave-absorbing material
The implementation steps of this example are as follows:
A. preparation of the mixture solution
According to the method, the ratio of the rare earth metal salt in grams to the solvent in milliliters is 1:5, praseodymium nitrate hexahydrate and maleic dihydrazide are mixed in a DMF solvent according to the mol ratio of 1:1.8, the ultrasonic frequency is 20kHz, and the power density is 0.3W/cm2Dissolving for 30min under the condition of (1) to obtain a mixture solution;
B. heat treatment of
Uniformly heating the mixture solution obtained in the step A to 190 ℃ in an oven at a heating speed of 10 ℃/min, and carrying out heat preservation treatment for 24 hours at the temperature;
C. washing machine
And C, cooling the mixture solution subjected to the heating treatment in the step B to room temperature at a cooling speed of 2 ℃/h, filtering, and treating the filter residue with DMF (dimethyl formamide) washing liquor according to a volume ratio of the filter residue to the washing liquor of 1: washing for 4 times, and collecting rare earth metal organic complex particles;
D. soaking
C, soaking the rare earth metal organic complex obtained in the step C in DMF at room temperature according to the volume ratio of the rare earth metal organic complex to the DMF of 1:4, and replacing the DMF once every 12 hours of soaking; then, according to the volume ratio of the rare earth metal organic complex to acetone of 1:3, soaking the rare earth metal organic complex soaked in DMF in acetone at room temperature, and replacing new acetone once every 12 hours of soaking;
E. thermal treatment
And activating the soaked rare earth metal organic complex at the temperature of 146 ℃ for 6 hours, and grinding the mixture into 150-mesh powder to obtain the wave-absorbing material.
The wave-absorbing material prepared in this example is subjected to X-ray diffraction analysis according to the method described in the specification, and the analysis result is shown in fig. 1, and the topological structure analysis result is shown in fig. 2. The cell parameters of the rare earth metal organic complex wave-absorbing material of the invention are calculated according to diffraction parameters by the results shown in the attached figure 1 as follows:
a＝17.6539(15)，b＝13.148(11)，c＝14.0261(12)；
the result of measuring the wave-absorbing performance of the rare earth metal organic complex wave-absorbing material by using an Agilent E8363B vector network analyzer according to a coaxial method is shown in figure 3, and figure 3 shows the absorption condition of the wave-absorbing material with different thicknesses on electromagnetic waves with different frequencies. When the thickness of the wave-absorbing material reaches 2.5mm, the wave-absorbing material has reflection loss below-10 dB. When the thickness is 5.5mm, the maximum reflection loss is-48.832 dB, which shows that the wave-absorbing material prepared in example 1 has excellent wave-absorbing performance.
Example 2: preparation of rare earth metal organic complex wave-absorbing material
The implementation steps of this example are as follows:
A. preparation of the mixture solution
According to the ratio of the rare earth metal salt in grams to the solvent in milliliters of 1:4, the lanthanum chloride rare earth metal salt and the maleic dihydrazide are mixed in the ethanol solvent according to the mol ratio of 1:1.5, the ultrasonic frequency is 30kHz, and the power density is 0.33W/cm2Dissolving for 25min under the condition of (1) to obtain a mixture solution;
B. heat treatment of
Uniformly heating the mixture solution obtained in the step A to 150 ℃ in an oven at a heating speed of 12 ℃/min, and carrying out heat preservation treatment for 72h at the temperature;
C. washing machine
And C, cooling the mixture solution subjected to the heating treatment in the step B to room temperature at a cooling speed of 5 ℃/h, filtering, and using ethanol washing liquor for filter residue according to the volume ratio of the filter residue to the washing liquor of 1:2, washing for 2 times, and collecting rare earth metal organic complex particles;
D. soaking
C, soaking the rare earth metal organic complex obtained in the step C in DMF at room temperature according to the volume ratio of the rare earth metal organic complex to the DMF of 1:2, and replacing the DMF once every 12 hours of soaking; then, according to the volume ratio of the rare earth metal organic complex to the acetone of 1:2, soaking the rare earth metal organic complex soaked in the DMF in the acetone at room temperature, and replacing the acetone with new acetone once every 12 hours of soaking;
E. thermal treatment
And activating the soaked rare earth metal organic complex at the temperature of 140 ℃ for 8 hours, and grinding the mixture into 300-mesh powder to obtain the wave-absorbing material.
The wave-absorbing material prepared in the embodiment is subjected to X-ray diffraction analysis according to the method described in the specification, the analysis result is similar to that of the attached drawing 1, and the topological structure analysis result is similar to that of the attached drawing 2. The cell parameters of the rare earth metal organic complex wave-absorbing material are calculated according to diffraction data by the result as follows:
a＝17.5663(6)，b＝13.0743(5)，c＝14.1771(5)；
the results of measuring the wave-absorbing performance of the rare earth metal organic complex wave-absorbing material by using an Agilent E8363B vector network analyzer according to a coaxial method refer to the attached figure 4, and the attached figure 4 shows the absorption condition of the wave-absorbing material with different thicknesses on electromagnetic waves with different frequencies. When the thickness of the wave-absorbing material reaches 2.5mm, the wave-absorbing material has reflection loss below-10 dB. When the thickness is 4.5mm, the maximum reflection loss is-30.6. dB, which shows that the wave-absorbing material prepared by the embodiment has excellent wave-absorbing performance.
Example 3: preparation of rare earth metal organic complex wave-absorbing material
The implementation steps of this example are as follows:
A. preparation of the mixture solution
According to the ratio of the rare earth metal salt in grams to the solvent in milliliters of 1:8, the lanthanum sulfate rare earth metal salt and the maleic dihydrazide are mixed in the water solvent according to the mol ratio of 1:2.5, the ultrasonic frequency is 35kHz, and the power density is 0.32W/cm2Dissolving for 35min under the condition of (1) to obtain a mixture solution;
B. heat treatment of
Uniformly heating the mixture solution obtained in the step A to 160 ℃ in an oven at a heating speed of 14 ℃/min, and carrying out heat preservation treatment for 50h at the temperature;
C. washing machine
And C, cooling the mixture solution subjected to the heating treatment in the step B to room temperature at a cooling speed of 10 ℃/h, filtering, and mixing the filter residue with water according to a volume ratio of the filter residue to the washing liquid of 1:4, washing for 5 times, and collecting rare earth metal organic complex particles;
D. soaking
C, soaking the rare earth metal organic complex obtained in the step C in DMF at room temperature according to the volume ratio of the rare earth metal organic complex to the DMF of 1:3, and replacing the DMF once every 12 hours of soaking; then, according to the volume ratio of the rare earth metal organic complex to the acetone of 1:5, soaking the rare earth metal organic complex soaked in the DMF in the acetone at room temperature, and replacing the acetone with new acetone once every 12 hours of soaking;
E. thermal treatment
And activating the soaked rare earth metal organic complex at the temperature of 154 ℃ for 3h, and grinding the mixture into 180-mesh powder to obtain the wave-absorbing material.
The wave-absorbing material prepared in the embodiment is subjected to X-ray diffraction analysis according to the method described in the specification, the analysis result is similar to that of the attached drawing 1, and the topological structure analysis result is similar to that of the attached drawing 2. The cell parameters of the rare earth metal organic complex wave-absorbing material are calculated according to diffraction data by the result as follows:
a＝17.3456(6)，b＝13.7568(5)，c＝14.2497(5)
the result of measuring the wave-absorbing performance of the rare earth metal organic complex wave-absorbing material by using an Agilent E8363B vector network analyzer according to a coaxial method is shown in figure 5, and figure 5 shows the absorption condition of the wave-absorbing material with different thicknesses on electromagnetic waves with different frequencies. When the thickness of the wave-absorbing material reaches 2.5mm, the wave-absorbing material has reflection loss below-10 dB. When the thickness is 4.5mm, the maximum reflection loss is-25.26 dB, which shows that the wave-absorbing material prepared by the embodiment has excellent wave-absorbing performance.
Example 4: preparation of rare earth metal organic complex wave-absorbing material
The implementation steps of this example are as follows:
A. preparation of the mixture solution
According to the ratio of the rare earth metal salt in grams to the solvent in milliliters of 1:6, the neodymium nitrate hexahydrate and the maleic dihydrazide are mixed in DMF solvent according to the mol ratio of 1:2.2, the ultrasonic frequency is 40kHz, and the power density is 0.35W/cm2Dissolving for 28min under the condition of (1) to obtain a mixture solution;
B. heat treatment of
Uniformly heating the mixture solution obtained in the step A to 180 ℃ in an oven at a heating speed of 15 ℃/min, and carrying out heat preservation treatment for 32h at the temperature;
C. washing machine
And C, cooling the mixture solution subjected to the heating treatment in the step B to room temperature at a cooling speed of 8 ℃/h, filtering, and treating the filter residue with DMF (dimethyl formamide) washing liquor according to the volume ratio of the filter residue to the washing liquor of 1:3, washing for 3 times, and collecting rare earth metal organic complex particles;
D. soaking
C, soaking the rare earth metal organic complex obtained in the step C in DMF at room temperature according to the volume ratio of the rare earth metal organic complex to the DMF of 1:5, and replacing the DMF once every 12 hours of soaking; then, according to the volume ratio of the rare earth metal organic complex to acetone of 1:4, soaking the rare earth metal organic complex soaked in DMF in acetone at room temperature, and replacing new acetone once every 12 hours of soaking;
E. thermal treatment
And activating the soaked rare earth metal organic complex at 160 ℃ for 1h, and grinding the mixture into 240-mesh powder to obtain the wave-absorbing material.
The wave-absorbing material prepared in the embodiment is subjected to X-ray diffraction analysis according to the method described in the specification, the analysis result is similar to that of the attached drawing 1, and the topological structure analysis result is similar to that of the attached drawing 2. The cell parameters of the rare earth metal organic complex wave-absorbing material are calculated according to diffraction data by the result as follows:
a＝17.6286(15)，b＝13.0641(11)，c＝13.9887(12)；
the results of measuring the wave-absorbing performance of the rare earth metal organic complex wave-absorbing material by using an Agilent E8363B vector network analyzer according to a coaxial method refer to the attached figure 6, and the attached figure 6 shows the absorption condition of the wave-absorbing material with different thicknesses on electromagnetic waves with different frequencies. When the thickness of the wave-absorbing material reaches 3.5mm, the wave-absorbing material has reflection loss below-10 dB. When the thickness is 4.5mm, the maximum reflection loss is-20.34 dB, which shows that the wave-absorbing material prepared by the embodiment has excellent wave-absorbing performance.
Claims (9)
1. The rare earth metal organic complex wave-absorbing material is characterized in that the wave-absorbing material is a mononuclear complex single crystal formed by coordinating praseodymium rare earth metal ions with maleic dihydrazide, and the three-dimensional structural formula of the wave-absorbing material is as follows:
in the formula:
pr1A and Pr1B represent metal ions Pr (III) involved in coordination; N3-N6 respectively represent nitrogen atoms of maleic dihydrazide molecules which do not participate in coordination; N2A-N2B respectively represent nitrogen atoms which participate in coordination and do not participate in coordination in the maleic dihydrazide molecule; N1A-N1B respectively represent nitrogen atoms which participate in coordination and do not participate in coordination in the maleic dihydrazide molecule; O1A-O6A respectively represent oxygen atoms which participate in coordination of the maleic dihydrazide; O1B-O6B respectively represent oxygen atoms which participate in coordination of the maleic dihydrazide; O1C-O6C respectively represent oxygen atoms participating in coordination in a maleic dihydrazide molecule; O1D-O6D respectively represent oxygen atoms participating in coordination in a maleic dihydrazide molecule;
unit cell parameters: 17.6539(15), 13.148(11), 14.0261 (12);
the wave absorbing performance is as follows: the wave-absorbing material has reflection loss below-10 dB when the thickness reaches 2.5 mm; the maximum reflection loss is-48.832 dB when the thickness is 5.5 mm.
2. The rare earth metal organic complex wave-absorbing material as claimed in claim 1, wherein the praseodymium rare earth metal is replaced by lanthanum, cerium, neodymium or scandium rare earth metal.
3. The preparation method of the rare earth metal organic complex wave-absorbing material according to claim 1 or 2, characterized in that the preparation method comprises the following steps:
A. preparation of the mixture solution
Mixing rare earth metal salt and maleic dihydrazide according to a molar ratio of 1: 1.5-4.5, performing ultrasonic dissolution in a solvent to obtain a mixture solution; the rare earth metal salt is rare earth metal salt of praseodymium nitrate hexahydrate, lanthanum nitrate hexahydrate, cerium nitrate hexahydrate, neodymium nitrate hexahydrate, lanthanum nitrate hexahydrate, scandium chloride, lanthanum chloride, cerium chloride, neodymium chloride, scandium sulfate, lanthanum sulfate, cerium sulfate or neodymium sulfate;
B. heat treatment of
Sealing the mixture solution obtained in the step A in a polytetrafluoroethylene reaction kettle, heating to 150-190 ℃ in an oven at a uniform heating speed, and carrying out heat preservation treatment at the temperature for 24-72 hours;
C. washing machine
Cooling the mixture solution heated in the step B to room temperature at a cooling speed of 2-10 ℃/h, filtering, washing filter residues with washing liquor, and collecting solid particles of the rare earth metal organic complex;
D. soaking
C, soaking the rare earth metal organic complex obtained in the step C in DMF at room temperature according to the volume ratio of the rare earth metal organic complex to DMF of 1: 2-5, and replacing DMF once every 12 hours; then, according to the volume ratio of the rare earth metal organic complex to acetone of 1: 2-5, soaking the rare earth metal organic complex soaked in DMF in acetone at room temperature, and replacing new acetone once every 12 hours of soaking;
E. thermal treatment
And activating the soaked rare earth metal organic complex at the temperature of 140-160 ℃ for 1-8 h, and grinding into powder to obtain the wave-absorbing material.
4. The method according to claim 3, wherein in step A, the solvent is DMF, ethanol or water.
5. The method according to claim 3, wherein in step A, the ultrasonic dissolution is carried out at an ultrasonic frequency of 20 to 40kHz and a power density of 0.3 to 0.35W/cm2Dissolving for 25-35 min under the condition (1).
6. The method according to claim 3, wherein in the step B, the uniform heating rate is 10 to 15 ℃/min.
7. The preparation method according to claim 3, wherein in the step C, the filter residue is washed for 2-5 times with DMF, ethanol or water solvent according to the volume ratio of the filter residue to the solvent of 1: 2-4.
8. The preparation method according to claim 3, wherein in the step D, the rare earth metal organic complex obtained in the step C is soaked in DMF for 12-72 h; and then the solvent acetone is replaced to continuously soak for 12-72 h.
9. The preparation method according to claim 3, wherein in the step D, the particle size of the powdery wave-absorbing material is 150-300 meshes.
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