A low-conductivity amorphous alloy material and a preparation method thereof

Abstract

This invention provides a low-conductivity amorphous alloy material and its preparation method, belonging to the field of additive manufacturing. The preparation method includes the following steps: pre-oxidizing amorphous alloy powder under an oxidizing atmosphere to form an amorphous oxide layer on the surface of the amorphous alloy powder, thereby obtaining pre-treated amorphous alloy powder; and shaping the pre-treated amorphous alloy powder to obtain a low-conductivity amorphous alloy material. This invention, by pre-oxidizing the amorphous alloy powder and combining it with subsequent shaping processes to introduce an oxide interface layer into the amorphous alloy material, forms a network-like amorphous oxide interface. This not only effectively reduces the conductivity of the amorphous alloy material but also promotes the nucleation of the shear transition zone, avoiding the localization of shear deformation. Furthermore, the strong bonding between metal atoms and oxygen atoms on the amorphous oxide interface makes it difficult for the shear transition zone to expand through the oxide interface, thus promoting the improvement of material strength.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing, and more specifically, relates to a low-conductivity amorphous alloy material and its preparation method. Background Technology

[0002] Due to their unique amorphous structure, amorphous alloys do not have defects such as grain boundaries, dislocations and segregation common in crystalline alloys. At the same time, they have superior mechanical properties, good processing performance, corrosion resistance and excellent soft magnetic, hard magnetic and thermal and electrical conductivity compared to various traditional materials. They have broad potential prospects in many fields such as aerospace, precision instruments, military and chemical industries.

[0003] In the field of materials science, researchers have extensively explored ways to reduce the electrical conductivity of amorphous alloys, a research background stemming from the needs of several key application areas. First, amorphous alloys are widely used in magnetic applications, such as the cores of transformers and inductors, where reduced conductivity helps reduce eddy current losses and improve the efficiency of electronic devices. Second, in electromagnetic shielding, reducing the conductivity of amorphous alloys can enhance their shielding effect, effectively isolating electromagnetic interference and protecting sensitive electronic equipment from external interference. Furthermore, for some electronic devices, precise control of material conductivity is necessary to meet specific circuit performance requirements. In thermal management applications, the low thermal conductivity of amorphous alloys is often used in conjunction with reduced electrical conductivity to reduce heat conduction, maintain temperature stability, reduce energy loss, or prevent heat conduction to sensitive components. Finally, in optical applications, reducing the conductivity of amorphous alloys can affect their optical properties, enabling the control and modulation of light. These application needs have driven the research and development of low-conductivity amorphous alloys to achieve multifunctional applications of materials in various engineering fields. Therefore, reducing the electrical conductivity of amorphous alloys has become a research area with broad potential, aiming to meet the engineering needs of a variety of applications.

[0004] The following are common methods for reducing the electrical conductivity of amorphous alloys, but these methods also have some drawbacks: First, alloying and doping are widely used methods. By introducing impurity elements such as phosphorus, arsenic, or antimony, the resistivity of amorphous alloys is increased, which can reduce electrical conductivity, but may lead to changes in other properties, and the concentration and proportion of impurities need to be carefully controlled. Second, amorphization treatment affects electrical conductivity by controlling the cooling rate of amorphous alloys. Faster cooling rates usually result in an amorphous structure with lower electrical conductivity; however, amorphization treatment may require special preparation conditions, and the material may become more fragile. Additionally, pressure treatment is a method of changing the electrical conductivity of amorphous alloys by applying high pressure. It can alter the electronic structure, but requires high-pressure equipment and may negatively affect the mechanical properties of the material. Temperature control can also be used to adjust the electrical conductivity of amorphous alloys, but it requires maintaining the material's operating temperature within a specific temperature range, which is inconvenient in some applications. Surface treatment is a method to change the surface electrical conductivity of amorphous alloys, but its effect is usually limited and may require additional processing steps. Nanostructures and nanoalloys can significantly alter electrical conductivity, but the preparation and control of nanostructures are often more challenging and require complex fabrication techniques.

[0005] In summary, although various methods exist for controlling the electrical conductivity of amorphous alloys, each method has its own challenges and limitations. Therefore, finding a way to control the electrical conductivity of amorphous alloys without compromising their mechanical properties and while maintaining their fully amorphous structure has become a current research hotspot. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a low-conductivity amorphous alloy material and its preparation method, aiming to solve the problem that existing methods for controlling the conductivity of amorphous alloys cannot simultaneously ensure that mechanical properties are not reduced.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a low-conductivity amorphous alloy material is provided, the method comprising the following steps:

[0008] S1 involves placing the amorphous alloy powder in an oxidizing atmosphere for pre-oxidation treatment, thereby forming an amorphous oxide layer on the surface of the amorphous alloy powder to obtain the pre-treated amorphous alloy powder.

[0009] S2 shapes the pretreated amorphous alloy powder to obtain amorphous alloy material with low electrical conductivity.

[0010] As a further preferred embodiment, the amorphous alloy powder has a particle size of no more than 100 μm, a critical amorphous formation size of no less than 10 mm, a supercooled liquid phase temperature range of more than 50 K, and a thermoplastic forming capability index of more than 0.15.

[0011] As a further preferred embodiment, in step S1, the temperature of the pre-oxidation treatment is not higher than the glass transition temperature of the amorphous alloy powder.

[0012] As a further preferred embodiment, in step S1, the pre-oxidation treatment time is shorter than the incubation time at the pre-oxidation treatment temperature.

[0013] As a further preferred embodiment, in step S1, before performing the pre-oxidation treatment, the amorphous alloy powder is spread out, and the thickness of the spread out does not exceed 5 times the particle size of the amorphous alloy powder.

[0014] As a further preferred embodiment, the thickness of the amorphous oxide layer is 0.05 μm to 200 μm.

[0015] As a further preferred embodiment, in step S2, the amorphous alloy powder is formed using a discharge plasma sintering process, with the sintering temperature being the glass transition temperature of the amorphous alloy powder and 50K below it, and the heating rate being 50K / min to 100K / min.

[0016] As a further preferred embodiment, in step S2, the amorphous alloy powder is formed using a discharge plasma sintering process, and the holding time is 2 min to 10 min.

[0017] As a further preferred embodiment, in step S2, the amorphous alloy powder is formed using a discharge plasma sintering process, with a sintering pressure of 100MPa to 500MPa.

[0018] According to another aspect of the present invention, a low-conductivity amorphous alloy material is provided using the above-described preparation method.

[0019] In summary, the technical solutions conceived by this invention have the following beneficial effects compared with the prior art:

[0020] 1. This invention pre-oxidizes amorphous alloy powder and introduces an oxide interface layer into the amorphous alloy material through subsequent forming processes, thereby forming a network-like amorphous oxide interface. This not only effectively reduces the electrical conductivity of the amorphous alloy material, but also promotes the nucleation of the shear transition zone, avoiding the localization of shear deformation. Furthermore, the strong bonding between metal atoms and oxygen atoms on the amorphous oxide interface makes it difficult for the shear transition zone to expand through the oxide interface. Thus, not only is it not necessary to sacrifice the strength of the material to reduce electrical conductivity, but it can also promote the improvement of the material strength.

[0021] 2. In particular, the present invention uses a discharge plasma sintering process to form amorphous alloy powder, which can complete the forming of amorphous alloy powder in a relatively short time and at a low temperature, thereby avoiding the crystallization of amorphous alloy and achieving a uniform temperature distribution throughout the amorphous alloy material, which helps to maintain the uniformity of the amorphous structure. At the same time, the powder particles are deformed almost in situ during the sintering process, which can introduce a uniformly distributed oxide interface and achieve effective control over size and shape.

[0022] 3. Furthermore, by forming under high pressure, the present invention can reduce porosity, increase the density and hardness of the material, thereby improving the compactness and physical properties of amorphous alloy materials;

[0023] 4. The amorphous alloy material provided by this invention has controllable dimensions and good mechanical properties and arbitrarily adjustable electrical conductivity, which can be widely used in the fields of electronic technology, electromagnetic shielding and thermal management. At the same time, by introducing an oxide interface layer, not only the electrical conductivity of the amorphous alloy material can be controlled, but also the thermal conductivity of the amorphous alloy material can be controlled, thus playing an important role in electronic devices that require low thermal conductivity. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the preparation process of low-conductivity amorphous alloy materials provided in this embodiment of the invention.

[0025] Figure 2 These are SEM and WDS images of the amorphous alloy material prepared in Comparative Example 1 and the low-conductivity amorphous alloy materials prepared in Examples 1-3 of this invention, wherein (a) is the SEM image of Comparative Example 1, (b) is the SEM image of Example 1, (c) is the SEM image of Example 2, (d) is the SEM image of Example 3, (e) is the WDS image of Comparative Example 1, (f) is the WDS image of Example 1, (g) is the WDS image of Example 2, and (h) is the WDS image of Example 3.

[0026] Figure 3 These are the stress-strain curves of the amorphous alloy material prepared in Comparative Example 1 and the low-conductivity amorphous alloy materials prepared in Examples 1-3 of this invention, where S1 is Comparative Example 1, S2 is Example 1, S3 is Example 2, and S4 is Example 3.

[0027] Figure 4 The thermal conductivity of the amorphous alloy material prepared in Comparative Example 1 and the low electrical conductivity amorphous alloy materials prepared in Examples 1-3 of this invention is shown in the figure. S1 is Comparative Example 1, S2 is Example 1, S3 is Example 2, and S4 is Example 3.

[0028] Figure 5The electrical conductivity of the amorphous alloy material prepared in Comparative Example 1 and the low electrical conductivity amorphous alloy materials prepared in Examples 1-3 of this invention are shown in the figure. S1 is Comparative Example 1, S2 is Example 1, S3 is Example 2, and S4 is Example 3. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] like Figure 1 As shown, the present invention provides a method for preparing a low-conductivity amorphous alloy material, the method comprising the following steps:

[0031] S1 involves pre-oxidizing the amorphous alloy powder in an oxidizing atmosphere such as pure air or pure oxygen, thereby forming an amorphous oxide layer on the surface of the amorphous alloy powder to obtain pre-treated amorphous alloy powder. The temperature of the pre-oxidation treatment does not exceed the glass transition temperature T of the amorphous alloy powder. g ;

[0032] S2 shapes the pretreated amorphous alloy powder to obtain amorphous alloy material with low electrical conductivity, high density, and excellent mechanical properties. It contains a large number of network-like amorphous oxide interfaces.

[0033] This invention introduces an oxide interface layer into an amorphous alloy through pre-oxidation treatment and forming processes, allowing for arbitrary control of the thickness of the amorphous oxide interface and thus regulating the conductivity of the amorphous alloy. Because oxides have poor conductivity, doping the amorphous alloy with an oxide interface can affect the electron velocity, thereby reducing conductivity. Simultaneously, by introducing the oxide interface layer into the amorphous alloy to form a network of amorphous oxide interfaces, the material strength can be improved while reducing conductivity. On one hand, the amorphous oxide interface can effectively promote the nucleation of the shear transition zone, avoiding the localization of shear deformation; on the other hand, the strong bonding between metal atoms and oxygen atoms on the amorphous oxide interface makes it difficult for the shear transition zone to expand through the oxide interface. Therefore, shear deformation is strictly limited to the individual cells composed of the oxide interface, preventing the formation of mature shear bands. In this way, not only is the material's strength not sacrificed, but its strength can be improved, thus achieving higher mechanical properties while reducing the conductivity of the amorphous alloy material. Furthermore, this invention performs surface pre-oxidation treatment on the amorphous alloy powder, effectively overcoming the limitations of the amorphous alloy's glass-forming ability. Furthermore, by introducing an oxide interface layer into the amorphous alloy material, this invention can not only regulate the electrical conductivity of the amorphous alloy material, but also regulate its thermal conductivity, thus playing an important role in electronic devices that require low thermal conductivity.

[0034] Furthermore, before pre-oxidation treatment, the amorphous alloy powder is first uniformly dispersed by vibration. The amorphous alloy powder can be placed in a desiccator and dispersed by ultrasonic vibration, so that the amorphous alloy powder is evenly spread in the desiccator. The ultrasonic vibration time is not less than 10 minutes, and the powder thickness in the desiccator does not exceed 5 times the particle size of the amorphous alloy powder.

[0035] Furthermore, in step S1, the amorphous alloy powder is a spherical powder with a particle size not exceeding 100 μm. If the particle size of the amorphous alloy powder is too large, the number of introduced oxide interfaces will be limited, resulting in a smaller range of performance control and affecting the mechanical properties of the obtained low-conductivity amorphous alloy material. The critical size for amorphous formation of the amorphous alloy powder is not less than 10 mm, and the supercooled liquid phase temperature range ΔT... xA value greater than 50K, when ΔTx is large, indicates a significant undercooling range during the transition from a liquid to an amorphous state. This typically indicates high thermal stability, meaning the amorphous alloy maintains its amorphous structure over a wide temperature range without rapid crystallization. This is advantageous for the preparation and application of amorphous alloy materials, as they retain their unique properties and structure across a broad temperature spectrum. A thermoplastic forming capability index S greater than 0.15 generally signifies good thermoplastic forming performance. This indicates that amorphous alloys are easier to process during forming and may require lower forming temperatures and smaller strain stresses. In such cases, amorphous alloys may be suitable for fabricating complex parts or applications requiring precision forming. Zr is preferably used as the amorphous alloy powder. 55 Cu 30 Ni5Al 10 Cu 47 Zr 45 Al8 or Ti 41 Zr 25 Be 28 The thickness of the amorphous oxide layer formed on Cu6 ranges from 0.05 μm to 200 μm. The pre-oxidation temperature is not higher than the glass transition temperature T of the amorphous alloy powder. g The pre-oxidation treatment time is shorter than the incubation time corresponding to the pre-oxidation treatment temperature. The incubation time refers to the time it takes for an amorphous alloy to go from a completely amorphous state to the beginning of crystallization when it is kept at a certain temperature.

[0036] Furthermore, in step S2, the amorphous alloy powder is shaped using a spark plasma sintering (SPS) process, and the sintering temperature is the glass transition temperature T of the amorphous alloy powder. g At temperatures below 50 K, with a heating rate of 50 K / min to 100 K / min and a holding time of 2 min to 10 min, the interaction of these parameters allows for the production of highly densified, low-conductivity amorphous alloy materials while preventing crystallization. SPS (Sequencing Power Sequencing) processes can typically be performed under high pressure, which helps improve the density and physical properties of the amorphous alloy. The preferred sintering pressure is 100 MPa to 500 MPa. Sintering under high pressure reduces porosity and increases the density and hardness of the amorphous alloy material. Compared to other methods for controlling the conductivity of amorphous alloys, this invention allows for conductivity control by altering pre-oxidation treatment conditions and forming process parameters, and can better balance conductivity with other properties.

[0037] Amorphous alloys prepared using the SPS (Sintered Pulsed Separation) process exhibit a completely amorphous structure with numerous network-like amorphous oxide interfaces. During sintering, the powder particles deform almost in situ, introducing uniformly distributed oxide interfaces. Furthermore, this technology achieves a uniform temperature distribution throughout the sample, helping to maintain the homogeneity of the amorphous structure and addressing the issue of crystallization or inhomogeneous structures caused by temperature gradients in traditional sintering methods. Simultaneously, the SPS process typically completes the preparation of amorphous alloys in a relatively short time and at relatively low temperatures, thus avoiding crystallization. It can produce large-size samples, and due to their excellent mechanical properties and arbitrarily adjustable electrical conductivity, they can be widely applied in fields such as electronics, electromagnetic shielding, and thermal management. Moreover, the SPS process allows for effective control over the size and shape of the resulting conductive amorphous alloys, making them suitable for various applications.

[0038] According to another aspect of the present invention, a low-conductivity amorphous alloy material is provided using the above-described preparation method.

[0039] The technical solution provided by the present invention will be further described below with reference to specific embodiments.

[0040] Example 1

[0041] (1) Select Zr with an average particle size of 30 μm prepared by vacuum atomization. 55 Cu 30 Ni5Al 10 Amorphous alloy powder, Zr 55 Cu 30 Ni5Al 10 The critical size for the formation of amorphous alloys is greater than 20 mm, and the glass transition temperature T g The initial crystallization temperature is 685K, and the initial crystallization temperature is T. x It is 765K, and the liquidus temperature T L The K value is 1164 K, and the supercooled liquid phase range ΔT is... x =T x -T g =80K, thermoplastic forming capability index S=ΔT x / (T L -T g Zr = 0.167, indicating good amorphous forming ability; 55 Cu 30 Ni5Al 10 10g of amorphous alloy powder was placed in a desiccator and dispersed by ultrasonic vibration to ensure that the amorphous alloy powder was evenly spread in the desiccator.

[0042] (2) Place the ultrasonically vibrated amorphous alloy powder from step (1) together with the drying dish into a heat treatment furnace with pure oxygen, and perform low-temperature pre-oxidation treatment at 523K for 30 minutes to form an amorphous oxide layer on the surface of the amorphous alloy powder.

[0043] (3) The amorphous alloy powder after pre-oxidation treatment in step (2) is prepared by SPS. The sintering pressure is 500MPa, the sintering temperature is 685K, the heating rate is 50K / min, the holding time is 5min, and after cooling in the furnace, an amorphous alloy material with a large number of network-like amorphous oxide interfaces is obtained.

[0044] Example 2

[0045] Same as Example 1, except that in step (2), a low-temperature pre-oxidation treatment is performed at 573K for 30 minutes.

[0046] Example 3

[0047] Same as Example 1, except that in step (2), a low-temperature pre-oxidation treatment is performed at 623K for 30 minutes.

[0048] Example 4

[0049] Same as Example 1, except that in step (1), Cu with an average particle size of 30 μm prepared by vacuum atomization is selected. 47 Zr 45 Al8 amorphous alloy powder, Cu 47 Zr 45 The critical size for the formation of Al8 amorphous alloys is greater than 15 mm, and the glass transition temperature T0 is [not specified]. g The initial crystallization temperature is 714 K, and the initial crystallization temperature is T. x It is 794K, and the liquidus temperature T L The temperature range is 1190K, and the subcooled liquid phase range is ΔT. x =T x -T g =80K, thermoplastic forming capability index S=ΔT x / (T L -T g =0.168, which has good amorphous forming ability, and the sintering temperature of SPS in step (3) is 714K, the heating rate is 100K / min, the holding time is 2min, and the sintering pressure is 100MPa.

[0050] Example 5

[0051] Same as Example 1, except that in step (1), Ti particles with an average particle size of 30 μm prepared by vacuum atomization are selected. 41 Zr 25 Be 28Cu6 amorphous alloy powder, Ti 41 Zr 25 Be 28 The critical size for the formation of Cu6 amorphous alloys is greater than 15 mm, and the glass transition temperature T0 is [not specified]. g The initial crystallization temperature is 587 K, and the initial crystallization temperature is T. x The liquidus temperature is 684K, T. L The temperature range is 1130 K, and the subcooled liquid phase range is ΔT. x =T x -T g =97K, thermoplastic forming capability index S=ΔT x / (T L -T g =0.179, which has good amorphous forming ability, and in step (3), the sintering temperature of SPS is 587K, the heating rate is 80K / min, the holding time is 10min, and the sintering pressure is 200MPa.

[0052] Comparative Example 1

[0053] (1) Select Zr with an average particle size of 30 μm prepared by vacuum atomization. 55 Cu 30 Ni5Al 10 amorphous alloy powder;

[0054] (2) Amorphous alloy powder was prepared into a bulk material by SPS, with a sintering pressure of 500 MPa, a sintering temperature of 685 K, a heating rate of 50 K / min, a holding time of 5 min, and then cooled in the furnace to obtain the amorphous alloy material.

[0055] SEM images of the amorphous alloy material prepared in Comparative Example 1 and the low-conductivity amorphous alloy materials prepared in Examples 1-3 of this invention are shown below. Figure 2 As shown, the oxide interface layer thickness gradually increases with the increase of the pre-oxidation treatment temperature, indicating that the oxide interface layer thickness of amorphous alloy materials can be arbitrarily controlled by the present invention.

[0056] The stress-strain curves of the amorphous alloy material prepared in Comparative Example 1 and the low-conductivity amorphous alloy materials prepared in Examples 1-3 are shown below. Figure 3 As shown in the figure, the SPS sintered sample after pre-oxidation treatment not only did not reduce the strength of the amorphous alloy, but the strength of the sintered sample increased slightly with the increase of the pre-oxidation treatment temperature. This indicates that the microstructure of the amorphous alloy can be controlled without sacrificing the mechanical properties of the material.

[0057] The thermal conductivity of the amorphous alloy material prepared in Comparative Example 1 and the low electrical conductivity amorphous alloy materials prepared in Examples 1-3 of this invention is as follows: Figure 4As shown in the figure, the thermal conductivity of the SPS sintered sample after pre-oxidation treatment decreases with increasing pre-oxidation temperature. This indicates that the present invention can not only control the electrical conductivity of amorphous alloys, but also the thermal conductivity of amorphous alloys, which can play an important role in electronic devices that require low thermal conductivity.

[0058] The electrical conductivity of the amorphous alloy material prepared in Comparative Example 1 and the low-conductivity amorphous alloy materials prepared in Examples 1-3 of this invention is as follows: Figure 5 As shown in the figure, the conductivity of the SPS sintered sample after pre-oxidation treatment decreases by orders of magnitude as the pre-oxidation treatment temperature increases, indicating that the present invention can achieve arbitrary control of the conductivity of bulk amorphous alloys over a wide range.

[0059] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a low-conductivity amorphous alloy material, characterized in that, The preparation method includes the following steps: S1. The amorphous alloy powder is heated in an oxidizing atmosphere to perform pre-oxidation treatment, so that an amorphous oxide layer is formed on the surface of the amorphous alloy powder. The thickness of the amorphous oxide layer is 0.05μm to 200μm, thereby obtaining the pre-treated amorphous alloy powder. The temperature of the pre-oxidation treatment is not higher than the glass transition temperature of the amorphous alloy powder, and the time of the pre-oxidation treatment is lower than the incubation time at the pre-oxidation treatment temperature. S2 shapes the pretreated amorphous alloy powder to obtain amorphous alloy material with low electrical conductivity. The amorphous alloy powder is shaped using a discharge plasma sintering process with a holding time of 2 min to 10 min and a sintering pressure of 100 MPa to 500 MPa.

2. The method for preparing low-conductivity amorphous alloy material as described in claim 1, characterized in that, The amorphous alloy powder has an amorphous formation critical size of not less than 10 mm, a supercooled liquid phase temperature range of greater than 50 K, and a thermoplastic forming capability index of greater than 0.

15.

3. The method for preparing low-conductivity amorphous alloy material as described in claim 1, characterized in that, In step S1, before the pre-oxidation treatment, the amorphous alloy powder is spread out, and the thickness of the spread does not exceed 5 times the particle size of the amorphous alloy powder.

4. The method for preparing the low-conductivity amorphous alloy material according to any one of claims 1 to 3, characterized in that, In step S2, the amorphous alloy powder is shaped using a discharge plasma sintering process. The sintering temperature is the glass transition temperature of the amorphous alloy powder, and the heating rate is 50K / min~100K / min.

5. A low-conductivity amorphous alloy material obtained by the preparation method according to any one of claims 1 to 4.

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