A high-pressure synthesis method of a high-energy-density material P-1 LuN4

Abstract

The application relates to the technical field of lanthanide metal nitrogen-rich compounds, and particularly discloses a high-pressure synthesis method of a high-energy-density material P-1 LuN4, which comprises the following steps: S01: using a rhenium sheet as a sealing pad material, pre-pressing the rhenium sheet by using a diamond anvil cell device to form an indentation; S02: using a laser drilling machine to form a hole with a diameter of 100-105 mu m on the indentation, taking the hole as a pressure cavity; S03: placing a metal lutetium sheet in the center of the pressure cavity and filling liquid nitrogen, and then pressurizing to 20-30 GPa; and S04: laser heating the Lu / N2 mixture after pressurization to obtain P-1 LuN4 which stably exists under high pressure. The method aims to study the synthesis of lanthanide metal nitrogen-rich compounds, and provides a high-temperature and high-pressure synthesis method combining a diamond anvil cell device and laser heating, which is used for synthesizing lanthanide metal nitrogen-rich compounds.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lanthanide metal nitride compounds, and particularly discloses a high-pressure synthesis method of high-energy-density material P-1LuN4. BACKGROUND

[0002] Polymeric nitrogen releases a large amount of energy when it is converted into triple-bonded diatomic nitrogen (N2) molecules, and thus has attracted extensive research interest as a highly potential high-energy-density material (HEDM). Pressure can promote the electron delocalization of N2 molecules, thus favoring the formation of polymeric nitrogen. So far, four different single-bonded polymeric nitrogen allotropes such as Cg-N, LP-N, HLP-N and BP-N have been successfully synthesized by high-pressure technology. However, these polymeric nitrogens need to be synthesized under ultrahigh pressure conditions of more than 100 GPa and decompose when the pressure is lower than 48 GPa. The harsh preparation and storage conditions seriously hinder the practical application of polymeric nitrogen.

[0003] The introduction of metal cations can enhance the stability of polymeric nitrogen and reduce the formation pressure through charge transfer and Coulomb interaction. By introducing different metals, people have synthesized a variety of polymeric nitrogen structures, including: cyclic polymeric nitrogen structures (such as N5 ring, N6 ring, N 18 5- ∞ The selection of metals has an important influence on the formation and diversity of polymeric nitrogen. Lanthanide metals provide a new way for the stability of polymeric nitrogen structures due to their rich valence electrons and low electronegativity. The synthesis of lanthanide metal nitride compounds needs to be studied;

[0004] Diamond Anvil Cell (DAC) is an experimental device for generating ultrahigh pressure environment, and its core principle is to apply extremely high hydrostatic pressure to a small sample through two opposite diamond anvils. The anvil surface diameter of the diamond anvil is usually tens to hundreds of microns (such as 300 mu m), which can efficiently concentrate external pressure on the tip to form an ultrahigh pressure environment. The application provides a high-temperature and high-pressure synthesis method combining a diamond anvil cell device and laser heating. SUMMARY

[0005] The application aims to provide a high-temperature and high-pressure synthesis method combining a diamond anvil cell device and laser heating for synthesizing lanthanide metal nitride compounds in order to study the synthesis of lanthanide metal nitride compounds.

[0006] ​​In order to achieve the above object, the present application provides the following basic scheme:

[0007] A high-pressure synthesis method of a high-energy-density material P-1 LuN4, comprising the following steps:

[0008] S01: Using a diamond anvil cell device, a rhenium sheet is pre-pressed as a gasket material to form an indentation, and the indentation thickness is 40 µm-60 µm;

[0009] S02: Using a laser drilling machine, a hole with a diameter of 100 µm-105 µm is formed on the indentation, and the hole is used as a pressure cavity;

[0010] S03: A metal lutetium sheet is placed in the pressure cavity and filled with liquid nitrogen, and then pressurized to 20-30 GPa;

[0011] S04: The Lu / N2 mixture after pressurization is laser heated to obtain P-1 LuN4 which exists stably under high pressure.

[0012] Further, the anvil surface diameter of the diamond anvil cell device is 300 µm.

[0013] Further, the hole is located at the center of the indentation.

[0014] Further, the diameter of the hole is 103 µm.

[0015] Further, in step S03, the metal lutetium sheet is placed inside the pressure cavity, the metal lutetium sheet cannot cover the entire inside of the pressure cavity, then the upper cover part of the press is closed using the press, at this time the pressure cavity is closed, and the entire press is immersed in liquid nitrogen, after waiting for the liquid nitrogen to penetrate into the entire pressure cavity through the gap closed by the pressure cavity, the screw is tightened to seal the pressure cavity, then the press is taken out of the liquid nitrogen, and the pressure is increased to 20-30 GPa to form a high-pressure cavity.

[0016] Further, the pressurization pressure is 25.1 GPa.

[0017] Further, the anvil surface diameter of the diamond anvil cell device is 300 µm.

[0018] Further, in step S04, after the high-pressure cavity is formed, the Lu / N2 mixture is laser heated, the heating temperature is 2000 K-3000 K, and the heating time is 10-15 s.

[0019] Further, in step S04, after the Lu / N2 mixture is laser heated, a new Lu-N compound is obtained, and the new Lu-N compound is verified.

[0020] Further, the method further comprises step S05: performing XRD spectrum test and Raman spectrum test on the new Lu-N compound, and performing comparative analysis on the Lu-N compound LuNx (x=1-10) predicted by the CALYPSO structure prediction software, and confirming that the obtained Lu-N compound is P-1 LuN4.

[0021] The principle and effect of the scheme are that:

[0022] 1. Compared with the prior art, the application is a synthesis method of a new lanthanide metal nitrogen-rich energetic material. Compared with alkali metal, alkaline earth metal and other main group metal nitrogen-rich compounds, the synthesis pressure of the method is lower, and the high-temperature and high-pressure experiment method combining a diamond anvil cell and laser heating has the advantages of simple experimental operation and no impurities introduced into the synthesized sample in the synthesis of lanthanide metal nitrogen-rich compounds. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 An experimental process schematic diagram of a high-pressure synthesis method of a high-energy density material P-1 LuN4 proposed in an embodiment of the present application is shown;

[0025] Figure 2 An optical image in a high-pressure cavity in the high-pressure synthesis method of the high-energy density material P-1 LuN4 proposed in the embodiment of the present application is shown, wherein (a) is before heating and (b) is after heating;

[0026] Figure 3 A comparison diagram of Raman spectra before and after heating in the high-pressure synthesis method of the high-energy density material P-1 LuN4 proposed in the embodiment of the present application is shown;

[0027] Figure 4 A comparison diagram of XRD spectra of the sample after heating, N2 and theoretically calculated XRD spectra of metal Lu in the high-pressure synthesis method of the high-energy density material P-1 LuN4 proposed in the embodiment of the present application is shown;

[0028] Figure 5 A comparison diagram of XRD spectra of the sample after heating, Fm-3m LuN, P-1 LuN4 and theoretically calculated XRD of Im-3m Lu in the high-pressure synthesis method of the high-energy density material P-1 LuN4 proposed in the embodiment of the present application is shown;

[0029] Figure 6 A high-pressure synthesis method of a high-energy-density material P-1 LuN4 is shown in the Le bail refinement map proposed by the embodiment of the application;

[0030] Figure 7 A high-pressure synthesis method of a high-energy-density material P-1 LuN4 is shown in the experimental Raman and theoretical Raman comparison map proposed by the embodiment of the application;

[0031] Figure 8 A high-pressure synthesis method of a high-energy-density material P-1 LuN4 is shown in the schematic diagram of each angle of P-1 LuN4 structure. DETAILED DESCRIPTION

[0032] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined application purpose, the specific embodiments, structures, features and effects according to the application are described in detail as follows in combination with the drawings and preferred embodiments.

[0033] The embodiment is shown as follows: Figures 1-8

[0034] A high-pressure synthesis method of a high-energy-density material P-1 LuN4, comprising the following steps:

[0035] S01: Using rhenium sheet as sealing pad material, pre-pressing the rhenium sheet by using diamond anvil cell device to form indentation, and the indentation thickness is 40 µm-60 µm;

[0036] Regarding the diamond anvil cell device: the diamond anvil cell is an experimental device for generating ultra-high pressure environment, and its core principle is to apply extremely high hydrostatic pressure to a small sample through two opposite diamond anvils. It is a common experimental device for hydrostatic pressure. The key point of the diamond anvil cell device is to determine the anvil diameter. In this case, the anvil diameter is 300 µm, so that the indentation formed is clear and clear;

[0037] S02: Forming a hole with a diameter of 100 µm-105 µm on the indentation by using a laser drilling machine, and taking the hole as a pressure cavity; the hole is located at the center of the indentation. The reason for placing the hole at the center of the indentation is to avoid damage to the pressure cavity during pressurization;

[0038] S03: Placing the metal lutetium sheet into the pressure cavity and filling with liquid nitrogen, and then pressurizing to 20-30 GPa;

[0039] ​Specifically: In step S03, a thin sheet of lutetium metal is placed inside the pressure chamber, but the sheet does not completely cover the inside of the chamber. Then, the upper cover of the press is closed, sealing the pressure chamber. The entire press is then immersed in liquid nitrogen. After the liquid nitrogen has seeped into the entire pressure chamber through the sealed gaps, the screws are tightened to seal the chamber. The press is then removed from the liquid nitrogen and pressurized to 20-30 GPa. Experimental results show that a pressure of 25.1 GPa indicates the product obtained using this method is in optimal condition.

[0040] S04: The high-pressure cavity after pressurization is then heated by laser to obtain P-1 LuN4 that exists stably under high pressure.

[0041] Specifically: In step S04, a new Lu-N compound is obtained by laser heating the Lu / N2 mixture, and the new Lu-N compound is then verified.

[0042] Step S05: The new Lu-N compound was subjected to XRD and Raman spectroscopy tests, and compared with various Lu-N compounds LuNx (x=1-10) predicted by CALYPSO structure prediction software to confirm that the obtained Lu-N compound was P-1 LuN4.

[0043] like Figure 2 As shown, after heating to 2000 K-3000 K, the optical image inside the high-pressure chamber was observed. First, the changes in the morphology and color of the sample before and after heating were observed. After heating, the metallic luster of the sample disappeared, and a grayish-white sample was synthesized.

[0044] Regarding the grayish-white sample:

[0045] like Figure 3 As shown, Raman spectra of the samples before and after heating were performed. Before heating, all Raman peaks indicated by * can be attributed to N2, and no Raman peaks were observed in the metal. After heating, all Raman peaks indicated by * disappeared, and several broad Raman peaks as shown in the inset appeared, indicating that N2 had fully participated in the reaction and reacted with the metal to synthesize a new lutetium nitrogen compound.

[0046] At the same time, such as Figure 4 As shown, XRD spectra of the heated sample were analyzed. XRD spectra of N2 were acquired and the XRD spectra of Lu metal at this pressure were calculated for comparison. The results show that all samples *shown after heating cannot be attributed to the initial sample, indicating that the metal and N2 reacted to synthesize a new lutetium nitrogen compound.

[0047] like Figure 5 As shown, the XRD spectrum of the heated sample is compared with the predicted structures of various Lu-N compounds, LuN, using CALYPSO structure prediction software. xComparing (x=1-10), it was found that the newly emerging diffraction peaks match well with LuN and LuN4, such as Figure 6 As shown, Le Bail refinement of the XRD pattern at 25.1 GPa yielded reliability indices R0 and R1 respectively. wp =7.02% and R p =5.13%, confirming the synthesis of LuN4;

[0048] like Figure 7 As shown, the experimental Raman signal and the theoretically calculated Raman signal of P-1 LuN4 are compared and found to be quite similar, further confirming the existence of LuN4. Figure 8 As shown in the figure, the structural diagram of LuN4 shows that nitrogen is polymerized into an infinitely long nitrogen chain structure and an N4 short chain structure. The specific parameters are shown in Table 1.

[0049] Table 1

[0050]

[0051] This invention creates a novel method for synthesizing nitrogen-rich energetic materials of lanthanides. Compared with nitrogen-rich compounds of main group metals such as alkali metals and alkaline earth metals, this method has lower synthesis pressure. The high-temperature and high-pressure experimental method combining diamond anvil cell and laser heating has the advantages of simple experimental operation and no introduction of impurities into the synthesized samples in the synthesis of nitrogen-rich compounds of lanthanides.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for high-pressure synthesis of high-energy-density material P-1 LuN4, characterized by that, The method comprises the following steps: S01: Replacing the rhenium sheet as a gasket material and using a diamond anvil cell device, pre-pressing the rhenium sheet by using the diamond anvil cell device to form an indentation, and the indentation thickness is 40-60 µm; S02: Forming a hole with a diameter of 100-105 µm on the indentation by using a laser drilling machine, and taking the hole as a pressure cavity; S03: Placing a metal lutetium sheet in the center of the pressure cavity and filling liquid nitrogen, and then pressurizing to 20-30 GPa to form a high-pressure cavity; S04: Laser heating the Lu / N2 mixture after pressurization to obtain a P-1 LuN4 that stably exists under high pressure, and the heating temperature of laser heating the Lu / N2 mixture is 2000-3000 K, and the heating time is 10-15 s.

2. The high-pressure synthesis method of a high-energy-density material P-1 LuN4 according to claim 1, characterized in that, In step S01, the anvil surface diameter of the diamond anvil cell device is 300 µm.

3. The high-pressure synthesis method of a high-energy-density material P-1 LuN4 according to claim 2, characterized in that, In step S02, the hole is located at the center of the indentation.

4. The high-energy-density material P-1 LuN4 high-pressure synthesis method according to claim 1 or 3, characterized in that, The diameter of the hole is 103 µm.

5. The high-energy-density material P-1 LuN4 high-pressure synthesis method according to claim 4, characterized in that, In step S03, a metal lutetium sheet with a thickness of 10-30 µm and a length and width of 70 µm*40 µm is placed in the center of the pressure cavity, and then the upper cover part of the press is closed, at this time, the pressure cavity is closed, and the entire press is immersed in liquid nitrogen, after the liquid nitrogen seeps into the entire pressure cavity through the gap of the closed pressure cavity, the screw is tightened to seal the pressure cavity, and then the press is taken out of the liquid nitrogen, and then pressurized to 20-30 GPa to form a high-pressure cavity.

6. The high-pressure synthesis method of a high-energy-density material P-1 LuN4 according to claim 5, characterized in that, The pressurization pressure is 25.1 GPa.

7. The method according to claim 6, wherein the high-energy-density material P-1 LuN4 is synthesized at high pressure. In step S04, a new Lu-N compound is obtained after laser heating the Lu / N2 mixture, and the new Lu-N compound is verified.

8. The high-pressure synthesis method of a high-energy-density material P-1 LuN4 according to claim 7, characterized in that: The verification method is as follows: further comprising step S05: performing XRD spectrum test and Raman spectrum test on the new Lu-N compound, and comparing and analyzing with a plurality of Lu-N compounds LuNx predicted by the CALYPSO structure prediction software, wherein x=1-10, and confirming that the obtained Lu-N compound is P-1 LuN4.

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