Intermetallic compounds with negative expansion at room temperature Laves phase, their preparation and applications

Abstract

This invention discloses a room-temperature negatively expanding Laves phase intermetallic compound, its preparation, and its applications. The chemical formula of this room-temperature negatively expanding Laves phase intermetallic compound is Hf. x ,Ta a‑ x Nb b Fe2+, where 0.8525≤x≤0.875, 0.94≤a≤0.95, 0.05≤a≤0.06, has a hexagonal crystal system with space group P63 / mmc. It exhibits negative expansion characteristics in the temperature range of 219K~325K, with a linear expansion coefficient α. l ≤23×10 ‑6 K ‑1 This invention enhances negative expansion by introducing Ta into Hf-Fe2Laves metal and effectively broadens its negative expansion temperature range by introducing Nb. The synthesis method of this invention is simple and easy to implement, and it can be combined with positive expansion materials to achieve zero thermal expansion of the composite material at room temperature, thus possessing potential for room temperature applications.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, and in particular relates to a Laves phase intermetallic compound with negative expansion at room temperature, its preparation and application. Background Technology

[0002] In the field of materials science, conventional materials generally follow the principle of thermal expansion and contraction, which may lead to problems such as dimensional mismatch and loss of precision. The emergence of negative expansion materials provides a new direction for solving the problem of thermal mismatch. Controlling or combining zero expansion materials is expected to solve this problem. With the rapid development of industries such as aerospace, electronic information, and precision instruments, the dimensional changes caused by the thermal expansion of materials when equipment is operating in extreme temperature environments can lead to component deformation, performance degradation, or even failure. For example, in electronic packaging, the chip and substrate may experience thermal stress cracking due to the mismatch of their coefficients of thermal expansion, and aero-engine components may suffer fatigue damage due to thermal cycling.

[0003] Negative expansion intermetallic compounds, due to their unique crystal structure, exhibit negative thermal expansion characteristics as their crystal lattice contracts with increasing temperature. This effectively counteracts the positive thermal expansion of other materials, enabling precise control of their coefficient of thermal expansion. However, these materials currently face technical bottlenecks such as high brittleness, high preparation costs, limited temperature range to low temperatures, and insufficient long-term stability, restricting their large-scale application. There is an urgent need to develop new compositional designs and preparation processes to fully leverage the performance advantages of negative expansion intermetallic compounds and meet the pressing demand for thermally stable materials in high-end precision equipment. Summary of the Invention

[0004] This invention discloses a room-temperature negative expansion Laves phase intermetallic compound, its preparation and application, to solve any of the above-mentioned and other potential problems of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is: an intermetallic compound with a room-temperature negative expansion Laves phase, the chemical formula of which is: Hf x ,Ta a-x Nb b Fe2, wherein 0.8525≤x≤0.875, 0.94≤a≤0.95, 0.05≤b≤0.06, and the Laves phase intermetallic compound with negative expansion at room temperature has a hexagonal crystal system with space group P63 / mmc, and exhibits negative expansion characteristics in the temperature range of 219K~325K.

[0006] Furthermore, the linear expansion coefficient α of the Laves phase intermetallic compound with room temperature negative expansion is... l ≤-23×10 - 6 K -1It exhibits ferromagnetism and a distinct preferred orientation.

[0007] Furthermore, the chemical formula of the intermetallic compound with room-temperature negative expansion Laves phase is: Hf 0.875 Nb 0.05 Ta 0.075 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 265~325K, with a linear expansion coefficient α. l -27×10 - 6 K -1 .

[0008] Furthermore, the chemical formula of the intermetallic compound with room-temperature negative expansion Laves phase is Hf 0.8625 Nb 0.05 Ta 0.0875 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 252~306K, with a linear expansion coefficient α. l -31×10 - 6 K -1 .

[0009] Furthermore, the chemical formula of the intermetallic compound with room-temperature negative expansion Laves phase is Hf 0.8525 Nb 0.06 Ta 0.0875 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 219K~290K, with a linear expansion coefficient α. l -27×10 -6 K -1 .

[0010] Furthermore, the chemical formula of the intermetallic compound with room-temperature negative expansion Laves phase is Hf 0.865 Nb 0.06 Ta 0.075 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 248K~313K, with a linear expansion coefficient α. l -23×10 - 6 K -1 .

[0011] Another object of the present invention is to provide a method for preparing the above-mentioned intermetallic compound with room temperature negative expansion Laves phase, the method specifically comprising the following steps:

[0012] S1) According to Hf of Laves phase intermetallic compounds with negative expansion at room temperature x ,Ta a-x Nb b Fe2 requires the corresponding raw materials;

[0013] S2) Mix the raw materials prepared in S1);

[0014] S3) The raw materials mixed in S2) are smelted in an electric arc furnace at least 4 times;

[0015] S4) Anneal the uniformly fused sample under a protective atmosphere;

[0016] After annealing (S5), the metal is quenched in ice water to obtain an intermetallic compound with negative room temperature expansion of the Laves phase.

[0017] Furthermore, the purity of the Hf, Ta, Nb, and Fe metal raw materials in S1) is all >99.9%.

[0018] Furthermore, the specific annealing process in S4) is as follows: annealing at a temperature not lower than 1200℃ for at least 24 hours; the protective atmosphere is an inert gas.

[0019] The above-mentioned intermetallic compound with room temperature negative expansion Laves phase has applications in electronic packaging and integrated circuits, precision optics and aerospace devices.

[0020] Technical effects of the invention: By adopting the above technical solution, the present invention enhances the negative expansion of Hf-Fe2Laves metal by introducing Ta element and effectively broadens its negative expansion temperature range by introducing Nb element. It exhibits low expansion characteristics within the temperature range of 219~325K, possessing excellent thermal stability and high precision. Its significant feature is that its shape and size can shrink with increasing temperature within a specific temperature range, i.e., negative thermal expansion characteristics, and a linear expansion coefficient (α). l The values ​​are -31×10 -6 K -1 -27×10 -6 K -1 -27×10 -6 K -1 -23×10 -6 K -1 It exhibits both ferromagnetism and a distinct preferred orientation. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is the X-ray diffraction pattern of the Nb and Ta-doped Laves phase intermetallic compound prepared by the method of this invention at 300K;

[0023] Figure 2 This is an embodiment of the present invention, Hf. 0.875 Nb 0.05 Ta 0.075 Synchrotron X-ray diffraction pattern of Fe2 compound powder at 300K;

[0024] Figure 3 This is an embodiment of the present invention, Hf. 0.875 Nb 0.05 Ta 0.075 Electron backscattering diffraction pattern of Fe2 intermetallic compounds;

[0025] Figure 4 This is an embodiment of the present invention, Hf. 0.875 Nb 0.05 Ta 0.075 Magnetocaloric curves of Fe2 intermetallic compounds;

[0026] Figure 5 This is an embodiment of the present invention, Hf. 0.875 Nb 0.05 Ta 0.075 Temperature-dependent magnetization curves of Fe2 intermetallic compounds;

[0027] Figure 6 This is a linear expansion curve of the Nb and Ta-doped Laves phase intermetallic compounds prepared by the method of this invention. Detailed Implementation

[0028] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] It should be understood that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0031] This invention provides a Laves-phase intermetallic compound with negative room temperature expansion, the chemical formula of which is: Hf x ,Ta a-x Nb bFe2, wherein 0.8525≤x≤0.875, 0.94≤a≤0.95, 0.05≤b≤0.06, and the Laves phase intermetallic compound with negative expansion at room temperature has a hexagonal crystal system with space group P63 / mmc, and exhibits negative expansion characteristics in the temperature range of 219K~325K.

[0032] The preparation method includes the following steps:

[0033] S1) According to Hf of Laves phase intermetallic compounds with negative expansion at room temperature x ,Ta a-x Nb b Fe2 phase preparation of corresponding raw materials

[0034] S2) Mix the raw materials prepared in S1);

[0035] S3) The mixed raw materials shall be melted in an electric arc furnace at least four times;

[0036] S4) Place the uniformly melted sample under a protective atmosphere and anneal at a temperature not lower than 1200℃ for at least 24 hours;

[0037] After S5 annealing, an intermetallic compound with a negative expansion Laves phase at room temperature is obtained.

[0038] The protective atmosphere is an inert atmosphere.

[0039] Example 1:

[0040] The component described in this invention is Hf 0.8625 Nb 0.05 Ta 0.0875 Fe2+ ​​exhibits negative expansion at room temperature. Laves phase intermetallic compounds were synthesized using an electric arc furnace melting method.

[0041] The specific operation is carried out according to the following steps:

[0042] Weigh 5g of raw materials containing Hf, Nb, Ta, and Fe in a molar ratio of 0.8625:0.05:0.0875:2. Mix the raw materials in an electric arc furnace and evacuate the furnace (vacuum degree <2×10). -3 The sample was then repeatedly melted twice under an inert Ar atmosphere, each time for 2 minutes. The resulting sample was then annealed at 1200℃ for 24 hours under an inert atmosphere. X-ray diffraction results showed that the obtained product was Hf. 0.8625 Nb 0.05 Ta 0.0875The Fe2+ phase is pure and free of other impurities. Its hexagonal compound exhibits a distinct preferred orientation, and magnetic testing shows ferromagnetism. The magnetization at 200 K is 48.2 emu / g. It exhibits negative expansion characteristics in the temperature range of 252–306 K, with a linear expansion coefficient α. l -31×10 -6 K -1 .

[0043] Example 2:

[0044] The component described in this invention is Hf 0.875 Nb 0.05 Ta 0.075 Fe2+ ​​exhibits room-temperature negative expansion Laves phase intermetallic compounds, which were synthesized using an electric arc furnace melting method.

[0045] The specific steps are as follows:

[0046] Weigh 5g of raw materials containing Hf, Nb, Ta, and Fe in a molar ratio of 0.875:0.05:0.075:2. Mix the raw materials in an electric arc furnace and evacuate the furnace (vacuum degree <2×10). -3 The sample was then repeatedly melted three times under an inert Ar atmosphere, each time for 2 minutes. The resulting sample was then annealed at 1220℃ for 24 hours under an inert atmosphere. X-ray diffraction results showed that the obtained product was Hf. 0.875 Nb 0.05 Ta 0.075 Fe2 pure phase, without other impurities, such as Figure 1 and Figure 2 As shown, its hexagonal phase compounds also exhibit a clear preferred orientation, such as Figure 3 As shown, magnetic testing reveals the presence of ferromagnetism, such as... Figure 4 As shown, its magnetic transition temperature is 310K, its magnetization at 200K is 54.7 emu / g, it exhibits negative expansion characteristics in the temperature range of 265~325K, and its linear expansion coefficient α is... l -27×10 -6 K -1 .

[0047] Example 3:

[0048] The component described in this invention is Hf 0.8525 Nb 0.06 Ta 0.0875 Fe2+ ​​exhibits room-temperature negative expansion Laves phase intermetallic compounds, which were synthesized using an electric arc furnace melting method.

[0049] The specific operation is carried out according to the following steps:

[0050] Weigh 5g of raw materials containing Hf, Nb, Ta, and Fe in a molar ratio of 0.8525:0.06:0.0875:2. Mix the raw materials in an electric arc furnace and evacuate the furnace (vacuum degree <2×10). -3 The sample was then repeatedly melted twice under an inert Ar atmosphere, each time for 2 minutes. The resulting sample was then annealed at 1210℃ for 36 hours under an inert atmosphere. X-ray diffraction results showed that the obtained product was Hf. 0.8525 Nb 0.06 Ta 0.0875 The Fe2+ phase is pure and free of other impurities. Its hexagonal compound exhibits a distinct preferred orientation, and magnetic testing shows ferromagnetism. The magnetization at 200 K is 48.7 emu / g. It exhibits negative expansion characteristics in the temperature range of 219 K to 290 K, with a linear expansion coefficient α. l -27×10 -6 K -1 .

[0051] Example 4:

[0052] The component described in this invention is Hf 0.865 Nb 0.06 Ta 0.075 Fe2+ ​​exhibits room-temperature negative expansion Laves phase intermetallic compounds, which were synthesized using an electric arc furnace melting method.

[0053] The specific operation is carried out according to the following steps:

[0054] Weigh 5g of raw materials containing Hf, Nb, Ta, and Fe in a molar ratio of 0.865:0.06:0.075:2. Mix the raw materials in an electric arc furnace and evacuate the furnace (vacuum degree <2×10). -3 The sample was then repeatedly melted four times under an inert Ar atmosphere, each time for 1 minute. The resulting sample was then annealed at 1250℃ for 48 hours under an inert atmosphere. X-ray diffraction results showed that the obtained product was Hf. 0.865 Nb 0.06 Ta 0.075 The Fe2+ phase is pure and free of other impurities. Its hexagonal compound exhibits a distinct preferred orientation, and magnetic testing shows ferromagnetism. The magnetization at 200 K is 49.7 emu / g. It exhibits negative expansion characteristics in the temperature range of 248 K to 313 K, with a linear expansion coefficient α. l -23×10 -6 K -1 .

[0055] Example 5:

[0056] The component described in this invention is Hf 0.865 Nb0.055 Ta 0.075 Fe2+ ​​exhibits room-temperature negative expansion Laves phase intermetallic compounds, which were synthesized using an electric arc furnace melting method.

[0057] The specific operation is carried out according to the following steps:

[0058] Weigh 5g of raw materials containing Hf, Nb, Ta, and Fe in a molar ratio of 0.86:0.055:0.095:2. Mix the raw materials in an electric arc furnace and evacuate the furnace (vacuum degree <2×10). -3 The sample was then repeatedly melted four times under an inert Ar atmosphere, each time for 1.5 min. The resulting sample was then annealed at 1260 °C for 46 h under an inert atmosphere. X-ray diffraction results showed that the obtained product was Hf. 0.86 Nb 0.055 Ta 0.095 The Fe2 pure phase contains no other impurities, and its hexagonal phase compounds exhibit a distinct preferred orientation. Magnetic tests show that it is ferromagnetic.

[0059] The intermetallic compounds Hf with negative expansion at room temperature Laves phase obtained in Examples 1, 2, 3, and 4 0.8625 Nb 0.05 Ta 0.0875 Fe2, Hf 0.875 Nb 0.05 Ta 0.075 Fe2, Hf 0.8525 Nb 0.06 Ta 0.0875 Fe2, Hf 0.865 Nb 0.06 Ta 0.075 Fe2+ ​​exhibits linear expansion, showing negative expansion characteristics in the temperature ranges of 252~306K, 265~325K, 219K~290K, and 248K~313K, with a thermal expansion coefficient of -31×10⁻⁶. -6 K -1 <α l <-23×10 -6 K -1 ,like Figure 6 As shown, its hexagonal phase compound also exhibits a distinct preferred orientation, and magnetic tests show ferromagnetism. The magnetization values ​​at 30 kOe on the 200 K curve are 48.2 emu / g, 54.7 emu / g, 48.7 emu / g, and 49.7 emu / g, respectively. Figure 5 As shown.

[0060] The foregoing has provided a detailed description of the room-temperature negative expansion Laves phase intermetallic compounds, their preparation, and applications provided in the embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the methods and core ideas of this application; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0061] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0062] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0063] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0064] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A Laves phase intermetallic compound exhibiting negative expansion at room temperature, characterized in that, The chemical formula of the Laves phase intermetallic compound with room temperature negative expansion is: Hf x Ta a-x Nb b Fe2, wherein 0.8525≤x≤0.875, 0.94≤a≤0.95, 0.05≤b≤0.06, and the Laves phase intermetallic compound exhibiting negative expansion at room temperature has a hexagonal crystal system with space group P63 / mmc, and exhibits negative expansion characteristics in the temperature range of 219K~325K; the linear expansion coefficient α l ≤-23×10 -6 K -1 It exhibits ferromagnetism and a distinct preferred orientation.

2. The intermetallic compound with room-temperature negative expansion Laves phase according to claim 1, characterized in that, The chemical formula of the Laves phase intermetallic compound with room temperature negative expansion is: Hf 0.875 Nb 0.05 Ta 0.075 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 265~325K, with a linear expansion coefficient α. l -27×10 -6 K -1 .

3. The intermetallic compound with room-temperature negative expansion Laves phase according to claim 1, characterized in that, The chemical formula of the Laves phase intermetallic compound with room temperature negative expansion is Hf 0.8625 Nb 0.05 Ta 0.0875 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 252~306K, with a linear expansion coefficient α. l -31×10 -6 K -1 .

4. The intermetallic compound with a room-temperature negative expansion Laves phase according to claim 1, characterized in that, The chemical formula of the Laves phase intermetallic compound with room temperature negative expansion is Hf 0.8525 Nb 0.06 Ta 0.0875 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 219K~290K, with a linear expansion coefficient α. l -27×10 -6 K -1 .

5. The intermetallic compound with a room-temperature negative expansion Laves phase according to claim 1, characterized in that, The chemical formula of the Laves phase intermetallic compound with room temperature negative expansion is Hf 0.865 Nb 0.06 Ta 0.075 Fe2+ ​​exhibits negative expansion characteristics in the temperature range of 248K~313K, with a linear expansion coefficient α. l -23×10 -6 K -1 .

6. A method for preparing the intermetallic compound with room-temperature negative expansion Laves phase as described in any one of claims 1-5, characterized in that, The method specifically includes the following steps: S1) According to Hf of Laves phase intermetallic compounds with negative expansion at room temperature x Ta a-x Nb b Fe2 requires the corresponding raw materials; S2) Mix the raw materials prepared in S1) to obtain a mixture; S3) The mixture obtained in S2) is smelted at least 4 times in an electric arc furnace to obtain a uniformly smelted sample; S4) The uniformly melted sample obtained in S3) is annealed under a protective atmosphere; S5) After annealing, the sample is placed in ice water for quenching to obtain an intermetallic compound with negative expansion of the Laves phase at room temperature.

7. The method according to claim 6, characterized in that, The purity of the Hf, Ta, Nb, and Fe metal raw materials in S1) is all >99.9%.

8. The method according to claim 6, characterized in that, The specific annealing process in S4) is as follows: annealing at a temperature not lower than 1200℃ for at least 24 hours; the protective atmosphere is an inert gas.

9. The application of a room-temperature negative expansion Laves phase intermetallic compound as described in any one of claims 1-5 in the fields of electronic packaging and integrated circuits, precision optics and aerospace devices.

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