CN111620696A - Preparation method of high-hardness ferromagnetic alpha-MnB - Google Patents

Preparation method of high-hardness ferromagnetic alpha-MnB Download PDF

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CN111620696A
CN111620696A CN202010515464.1A CN202010515464A CN111620696A CN 111620696 A CN111620696 A CN 111620696A CN 202010515464 A CN202010515464 A CN 202010515464A CN 111620696 A CN111620696 A CN 111620696A
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pressure
mnb
synthesis
alpha
temperature
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马帅领
崔田
包括
陶强
朱品文
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Jilin University
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Jilin University
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/5805—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on borides
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
    • C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
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Abstract

The invention discloses a preparation method of high-hardness ferromagnetic alpha-MnB, belonging to the technical field of preparation of high-mechanical-strength magnetic manganese boron ceramic materials. The invention has simple process flow and does not need complex synthesis processes such as material compounding, doping, aging and the like; the preparation process of the high-hardness magnetic material is simplified, and the preparation period and the sintering time of the material are shortened; the purity of the manganese boride (alpha-MnB) is improved by adjusting the proportion, the temperature and the pressure of simple substance raw materials, and the magnetic manganese boride (alpha-MnB) body material with high mechanical strength is designed and prepared.

Description

Preparation method of high-hardness ferromagnetic alpha-MnB
Technical Field
The invention belongs to the technical field of preparation of magnetic manganese boron ceramic materials with high mechanical strength, and relates to a preparation method of a new substance of high-hardness ferromagnetic manganese boride (alpha-MnB).
Background
Magnetic materials are widely applied in the fields of military, industry and the like, and are an important embodiment of the national manufacturing level. The continuous development and progress of engineering technology put forward higher and higher requirements on the magnetic performance of the magnetic material, and also put forward higher and higher requirements on the electrical, thermal stability, mechanical and other properties of the magnetic material. Especially in the fields of micro-electro-mechanical systems, magnetic recording heads, ultra-high speed motors and the like, the defect of poor mechanical properties of magnetic materials is gradually exposed, and the working requirements of the magnetic materials in the environments with high temperature, humidity and high mechanical load such as space, seabed, underground and the like for a long time cannot be met. Therefore, the preparation of magnetic materials integrating excellent magnetics, mechanics and good thermal stability is becoming a research hotspot in the field of magnetics.
At present, magnetic materials mainly comprise families such as metal alloys and metal oxides, and the systems mainly comprise metal bonds and ionic bonds, and the mechanical properties and stability of the magnetic materials are determined by the chemical bond composition characteristics of the magnetic materials. In order to improve the mechanical property of the magnetic material, people mainly improve the mechanical property by the methods of compounding the magnetic material with a high-hardness material, solid solution doping, aging and the like, but the common magnetic material has a limited lifting space due to a low hardness value, and the method greatly reduces the magnetic property of the magnetic material and is not beneficial to keeping the magnetic property of the magnetic material, so that the design and synthesis of the intrinsic high-hardness magnetic material have very important significance for application under extreme conditions. The manganese atom is the element with the largest number of unpaired electrons in the 3d transition metal, and the formed compound has stronger magnetism. The boron element can form stronger covalent bonds, and the formed compound generally has excellent mechanical properties, so that the compound formed by the manganese element and the boron element is a potential system of the high-hardness magnetic material, and the defects of the mechanical properties and the thermal properties of the magnetic material are overcome.
A large amount of chemical mixture ratio exists in a manganese-boron phase diagram, and five compounds Mn exist in the manganese-boron phase diagram at present2B、β-MnB、Mn3B4、MnB2、MnB4Since the phase boundaries of the manganese boron compound are blurred, the phases are easily transformed into each other, and it is difficult to synthesize a high-purity sample. Super highThe samples synthesized under the temperature condition are the main objects of attention of people, but the samples synthesized under the high temperature condition cause the abnormal enlargement of sample grains, which is not beneficial to the improvement of the mechanical property of the samples, and whether new high-hardness ferromagnetic manganese boron compounds exist at the low temperature or not is still an unexplored field, so that the design and preparation of novel high-strength magnetic manganese boron compounds at the relatively low temperature have very important significance for expanding the application range of magnetic materials.
Disclosure of Invention
The invention solves the technical problem of overcoming the defects in the background technology and provides a preparation method of high-hardness ferromagnetic alpha-MnB. The method does not need complex synthesis processes such as material compounding, doping, aging and the like, directly adjusts the components and purity of the manganese boron compound by mixing simple substance components and adjusting the synthesis temperature, and prepares the ferromagnetic alpha-MnB body material with high mechanical strength.
The specific technical scheme of the invention is as follows:
a preparation method of high-hardness ferromagnetic alpha-MnB takes manganese powder (Mn) and boron powder (B) as raw materials, and the alpha-MnB bulk material is prepared by the technical processes of raw material mixing, briquetting, assembling, high-temperature high-pressure synthesis, cooling and pressure relief; the raw materials are mixed, namely manganese powder and boron powder are mixed according to the molar ratio of 1: 1-2; the pressing block is formed by pressing the raw materials of the mixture into a cylinder shape according to the size of the synthesis cavity by using a hydraulic machine; the assembly is that the blocky cylindrical raw materials are put into a heating container and then are put into a synthesis cavity; the high-temperature high-pressure synthesis is carried out for 15-720 minutes under the conditions that the pressure is 1.0-5.0 GPa and the temperature is 800-1400K; and the step of cooling and pressure relief is to naturally cool the sample to normal temperature after the electrification and the heating are stopped, and then relieve the pressure to normal pressure.
Preferably, the manganese powder and boron powder are in a molar ratio of 1: 1.
Preferably, the particle size of the raw material is 1 to 5 μm.
Preferably, the high-temperature high-pressure synthesis is carried out, wherein the synthesis pressure is 5.0GPa, the synthesis temperature range is 1000-1400K, and the heat preservation and pressure maintaining are carried out for 20 minutes.
In order to ensure the temperature uniformity of a synthesis cavity in the process of synthesizing a sample, the method adopts an electrified graphite tube indirectly-heated type heating mode; in order to ensure that the sample does not react with the graphite tube, the cavity for synthesizing the sample is protected by hexagonal boron nitride.
Has the advantages that:
the invention has simple process flow; the method does not need complex processes such as material compounding, doping, aging and the like, and improves the purity of the alpha-MnB by adjusting the proportion, the temperature and the pressure of the simple substance raw materials, so as to prepare the block alpha-MnB material with higher purity. The method greatly shortens the preparation period and the sintering time of the traditional method, and the synthesized block material is beneficial to optimizing the magnetic and mechanical properties of the block material.
Drawings
FIG. 1 is an X-ray diffraction pattern of an α -MnB compound prepared in example 1.
Fig. 2 is a graph of hardness versus load for the α -MnB compound prepared in example 1.
Fig. 3 is a graph of magnetic susceptibility versus temperature for the α -MnB compound prepared in example 1.
Fig. 4 is a hysteresis chart of the α -MnB compound prepared in example 1.
Fig. 5 is a thermal stability diagram of the α -MnB compound prepared in example 1.
FIG. 6 is an X-ray diffraction pattern of an α -MnB compound prepared in example 2.
FIG. 7 is an X-ray diffraction pattern of an α -MnB compound prepared in example 3.
FIG. 8 is an X-ray diffraction pattern of an α -MnB compound prepared in example 4.
FIG. 9 is an X-ray diffraction pattern of an α -MnB compound prepared in example 5.
FIG. 10 is an X-ray diffraction pattern of a β -MnB compound prepared in example 6.
Detailed Description
Example 1
Manganese powder (Mn) with the analytical pure particle size of 1-5 microns and boron powder (B) with the particle size of 1-5 microns are fully mixed according to the molar ratio of 1:1, and a sample is filled into a synthesis cavity after the powder is pressed and formed by a hydraulic press. Graphite is adopted for heating in the assembly cavity, pyrophyllite is used as a heat insulation material, hexagonal boron nitride is used for protecting the cavity, the synthesis pressure is 5.0GPa, the synthesis temperature is 1400K, the heat preservation and pressure maintaining time is 20 minutes, the pressure is relieved after the sample is naturally cooled to the room temperature after the heating is stopped, and the specific X-ray diffraction result of the alpha-MnB prepared under the condition is shown in figure 1. Fig. 2 is a graph of hardness of the prepared α -MnB compound as a function of load, from which it can be seen that the hardness of the sample converges above 16GPa, much higher than that of the common magnetic materials. Fig. 3 is a graph of magnetic susceptibility versus temperature of the α -MnB compound prepared in example 1, from which it can be derived that the curie temperature of the sample is about 550K, indicating that the magnetic material can be used normally at room temperature. FIG. 4 is a hysteresis loop plot of the α -MnB compound prepared in example 1, with the sample having a magnetic saturation of about 110emu/g, indicating that the sample is a stronger ferromagnetic sample. Fig. 5 shows thermogravimetric and differential thermal curves of the α -MnB compound prepared in example 1, and a thermal stability test shows that the sample has an oxidation resistance temperature of more than 600 ℃ and has a strong oxidation resistance. It can be seen that the alpha-MnB synthesized by the method of the invention has higher mechanical strength and stronger ferromagnetic property at the same time, and is suitable for being applied in an extremely high load environment.
Example 2
The same raw materials as in example 1 are mixed according to a molar ratio of 1:2, the powder sample is assembled after being pressed and formed in the same way as in example 1, the synthesis pressure is 5.0GPa, the synthesis temperature is 1300K, the pressure and heat preservation time is 20 minutes, the sample is naturally cooled to room temperature after the heating is stopped, the pressure is released, and the sample prepared under the condition contains a small amount of Mn3B4The impurities, specific X-ray diffraction results are shown in figure 6. As can be seen from examples 1 to 2, the ratio of the synthesis should be controlled to 1:2 or less, preferably 1: 1.
Example 3
The same raw materials as in example 1 are mixed according to a molar ratio of 1:1, the powder sample is assembled after being pressed and molded in the same way as in example 1, the synthesis pressure is 5.0GPa, the synthesis temperature is 900K, the pressure and heat preservation time is 20 minutes, and the sample is naturally cooled to room temperature after the heating is stopped and then the pressure is released. Under the condition, alpha-MnB with higher purity is synthesized. The specific X-ray diffraction results are shown in fig. 7.
Example 4
The same raw materials as in example 1 are mixed according to a molar ratio of 1:1, the powder sample is assembled after being pressed and molded in the same way as in example 1, the synthesis pressure is 5.0GPa, the synthesis temperature is 1000K, the pressure and heat preservation time is 20 minutes, and the sample is naturally cooled to room temperature after the heating is stopped and then the pressure is released. Under the condition, alpha-MnB with higher purity is synthesized. The specific X-ray diffraction results are shown in fig. 8.
Example 5
The same raw materials as in example 1 were mixed in a molar ratio of 1:1, the powder sample was press-molded and assembled in the same manner as in example 1 under a synthesis pressure of 5.0GPa and a synthesis temperature of 1100K for 20 minutes, and the sample was naturally cooled to room temperature after the heating was stopped and then depressurized. Under the condition, alpha-MnB with higher purity is synthesized. The specific X-ray diffraction results are shown in fig. 9.
Example 6
The same raw materials as in example 1 are mixed according to a molar ratio of 1:1, the powder sample is assembled after being pressed and molded in the same way as in example 1, the synthesis pressure is 5.0GPa, the synthesis temperature is 1600K, the pressure and heat preservation time is 20 minutes, and the sample is naturally cooled to room temperature after the heating is stopped and then the pressure is released. Under the condition, the beta-MnB with higher purity is synthesized. The specific X-ray diffraction results are shown in fig. 10.
The experiments of examples 1-6 above were performed on a domestic SPD6 x 600T domestic hinged cubic press.
The results of the above examples 1-6 show that the temperature of the synthesis pressure and the proportion of the raw materials are important factors influencing the purity and the property of the synthesized α -MnB, that is, under the condition that the ratio of manganese to boron is 1: 1-1: 2 and within the temperature range of 900-1400K, a α -MnB sample with high purity can be obtained, that is, when the synthesis temperature is too high (1600K), the synthesized sample is β -MnB, and when the ratio of manganese to boron is higher than 1:2, more Mn appears3B4Impurities. The optimal preparation conditions are: manganese powder and boron powder are mixed according to the molar ratio of 1:1, the synthesis pressure is 5.0GPa, the synthesis temperature range is 1000-1400K, and the heat preservation and pressure maintaining are carried out for 20 minutes.

Claims (4)

1. A preparation method of high-hardness ferromagnetic alpha-MnB takes manganese powder and boron powder as raw materials, and the alpha-MnB bulk material is prepared by the technical processes of raw material mixing, briquetting, assembling, high-temperature high-pressure synthesis, cooling and pressure relief; the raw materials are mixed, namely manganese powder and boron powder are mixed according to the molar ratio of 1: 1-2; the pressing block is formed by pressing the raw materials of the mixture into a cylinder shape according to the size of the synthesis cavity by using a hydraulic machine; the assembly is that the blocky cylindrical raw materials are put into a heating container and then are put into a synthesis cavity; the high-temperature high-pressure synthesis is carried out for 15-720 minutes under the conditions that the pressure is 1.0-5.0 GPa and the temperature is 800-1400K; and the step of cooling and pressure relief is to naturally cool the sample to normal temperature after the electrification and the heating are stopped, and then relieve the pressure to normal pressure.
2. The method of claim 1, wherein the molar ratio of manganese powder to boron powder is 1: 1.
3. The method for preparing high-hardness ferromagnetic alpha-MnB as claimed in claim 1, wherein the particle size of the raw material is 1-5 μm.
4. The method for preparing high-hardness ferromagnetic alpha-MnB according to any one of claims 1 to 3, wherein the high-temperature high-pressure synthesis is carried out at a synthesis pressure of 5.0GPa and a synthesis temperature range of 1000 to 1400K, and the temperature and pressure are maintained for 20 minutes.
CN202010515464.1A 2020-06-09 2020-06-09 Preparation method of high-hardness ferromagnetic alpha-MnB Pending CN111620696A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114671454A (en) * 2022-03-22 2022-06-28 吉林大学 Method for synthesizing novel phase chalcocite-H copper sulfide ferromagnetic material at high temperature and high pressure

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5158913A (en) * 1987-02-20 1992-10-27 Stk Ceramics Laboratory Corp. Metal boride ceramic material
CN101973559A (en) * 2010-10-11 2011-02-16 吉林大学 Method for preparing boride of manganese at high temperature and high pressure
CN102001673A (en) * 2010-12-27 2011-04-06 鲍迎全 Method for producing high-purity manganese boride
CN102787267A (en) * 2012-09-04 2012-11-21 四川大学 Multiple boride metal ceramic based on high-entropy alloy adhesion agent and preparation method thereof
US20180005736A1 (en) * 2015-01-29 2018-01-04 The Florida State University Research Foundation, Inc. Method for tuning the ferromagnetic ordering temperature of aluminum iron boride

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5158913A (en) * 1987-02-20 1992-10-27 Stk Ceramics Laboratory Corp. Metal boride ceramic material
CN101973559A (en) * 2010-10-11 2011-02-16 吉林大学 Method for preparing boride of manganese at high temperature and high pressure
CN102001673A (en) * 2010-12-27 2011-04-06 鲍迎全 Method for producing high-purity manganese boride
CN102787267A (en) * 2012-09-04 2012-11-21 四川大学 Multiple boride metal ceramic based on high-entropy alloy adhesion agent and preparation method thereof
US20180005736A1 (en) * 2015-01-29 2018-01-04 The Florida State University Research Foundation, Inc. Method for tuning the ferromagnetic ordering temperature of aluminum iron boride

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
S. KLEMENZ ET.AL: "Low-temperature synthesis of nanoscale ferromagnetic α’-MnB", 《DALTON TRANSACTIONS》 *
SHIYU ZHU ET.AL: "Insight into the elastic, electronic properties, anisotropy in elasticity of Manganese Borides", 《VACUUM》 *
马帅领: "锰硼化合物的高温高压合成及物性研究", 《中国博士学位论文电子期刊网》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114671454A (en) * 2022-03-22 2022-06-28 吉林大学 Method for synthesizing novel phase chalcocite-H copper sulfide ferromagnetic material at high temperature and high pressure
CN114671454B (en) * 2022-03-22 2022-11-29 吉林大学 Method for synthesizing new-phase chalcocite-H copper sulfide ferromagnetic material at high temperature and high pressure

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