Preparation method of Ho2Fe17-based zero thermal expansion composite material

Abstract

The invention discloses a preparation method of a Ho2Fe17-based zero thermal expansion composite material, and belongs to the technical field of zero thermal expansion material preparation, the preparation method comprises the following steps: S1, preparing Ho2Fe17-based powder, and carrying out pickling pretreatment on the Ho2Fe17-based powder; s2, the Ho2Fe17-based powder subjected to acid pickling pretreatment is suspended in the copper plating solution to be subjected to dip plating treatment; s3, Ho2Fe17 / Cu is taken out of the copper plating solution to be cleaned and dried, and a core-shell-shaped Ho2Fe17 / Cu composite powder material is obtained; s4, the core-shell-shaped Ho2Fe17 / Cu composite powder is placed in a vacuum hot pressing furnace to be subjected to vacuum hot pressing treatment, and then the Ho2Fe17-based zero-thermal-expansion composite material with the isotropic zero-thermal-expansion performance is generated; the isotropic Ho2Fe17 / Cu block composite material with zero thermal expansion and high compressive strength is obtained by chemical copper plating and vacuum hot press molding.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of zero thermal expansion materials, in particular to a Ho2Fe 17 The invention discloses a preparation method of a zero thermal expansion composite material. Background Art

[0002] Most materials in nature exhibit the phenomenon of "expansion with heat and contraction with cold" when the temperature changes, that is, positive thermal expansion (PTE). Typical examples include pure metals (such as Cu, Fe) and ceramic materials Al2O3, SiO2, etc. However, a few materials exhibit abnormal thermal expansion. For example, in a specific temperature range, the size of some materials shrinks as the temperature increases, which shows negative thermal expansion (NTE); there are also very few materials whose size remains almost constant as the temperature increases within a certain temperature range, that is, zero thermal expansion (ZTE) materials. The linear expansion coefficient ( α l ) is greater than 2×10 -6 K -1 The material is called positive thermal expansion material, which is -2×10 -6 K -1 ≤ α l ≤2×10 -6 K -1 The material is called zero thermal expansion material. α l <-2×10 -6 K -1 Materials with negative thermal expansion are called negative thermal expansion materials. Among them, negative thermal and zero thermal expansion materials are collectively referred to as anomalous thermal expansion materials.

[0003] Zero thermal expansion materials maintain excellent dimensional stability in variable temperature environments and are essential basic materials for the manufacture of high-precision instruments and high-end equipment. In addition, adding negative thermal expansion materials as compensators to normal thermal expansion materials can also achieve zero thermal expansion characteristics, thereby achieving dimensional stability. Intermetallic compound Ho2Fe 17 It has attracted much attention due to its negative thermal expansion properties in a wide temperature range. However, the thermal expansion effect of this material is anisotropic and has low strength, which seriously restricts its practical application. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to obtain isotropic Ho2Fe2O3 with zero thermal expansion and high compressive strength by chemical copper plating and vacuum hot pressing. 17 / Cu bulk composite materials.

[0005] A Ho2Fe 17 A method for preparing a zero thermal expansion composite material comprises the following steps: S1: Prepare Ho2Fe with particle size of 50-200 μm 17 Base powder, and the Ho2Fe 17 The base powder is pre-treated by pickling; S2: prepare copper plating solution, and add the Ho2Fe 17 The base powder is suspended in the copper plating solution and immersed in the copper plating solution to form Ho2Fe 17 / Cu, wherein the Ho2Fe 17 The content of the base powder relative to the copper plating solution is 10-20 g / L, the immersion plating temperature is 25° C.-45° C., and the immersion plating time is 120 min-500 min; S3: The Ho2Fe 17 / Cu is taken out from the copper plating solution, cleaned and dried to obtain core-shell Ho2Fe 17 / Cu composite powder material; S4: The core-shell Ho2Fe 17 The / Cu composite powder is placed in a vacuum hot pressing furnace for vacuum hot pressing to generate Ho2Fe with isotropic zero thermal expansion performance. 17 The zero thermal expansion composite material is prepared, wherein the vacuum hot pressing treatment temperature is 950° C.-1100° C., the vacuum hot pressing treatment pressure is 500 MPa-3000 MPa, and the vacuum hot pressing treatment time is 1 min-4 min.

[0006] As a preferred technical solution of the present invention, the immersion plating treatment time is 180 min-300 min.

[0007] As a preferred technical solution of the present invention, the immersion plating treatment temperature is 40°C.

[0008] As a preferred technical solution of the present invention, the copper plating solution includes water, CuSO4·5H2O, C 10 H 14 N2Na2O8, K4[Fe(CN)6]·3H2O, HCHO, NaKC4H4O6·4H2O and C 10 H8N2.

[0009] As a preferred technical solution of the present invention, the concentration of CuSO4·5H2O in the copper plating solution is 10-15g / L. 10 H 14The concentration of N2Na2O8 in the copper plating solution is 15-20g / L, the concentration of K4[Fe(CN)6]·3H2O in the copper plating solution is 30-35mg / L, the concentration of HCHO in the copper plating solution is 5-7g / L, the concentration of NaKC4H4O6·4H2O in the copper plating solution is 10-15g / L, and the concentration of C 10 The concentration of H8N2 in the copper plating solution is 10-20 mg / L.

[0010] As a preferred technical solution of the present invention, the vacuum hot pressing treatment time is 2 minutes.

[0011] As a preferred technical solution of the present invention, the vacuum hot pressing treatment temperature is 1070° C., and the vacuum hot pressing treatment pressure is 2000 MPa.

[0012] As a preferred technical solution of the present invention, prepare Ho2Fe with a particle size of 100-150 μm. 17 Base powder.

[0013] As a preferred technical solution of the present invention, the S1 and the Ho2Fe 17 The pickling pretreatment of the base powder specifically includes: The Ho2Fe 17 The base powder is pre-treated by pickling.

[0014] As a preferred technical solution of the present invention, the Ho2Fe 17 Taking out / Cu from the copper plating solution for cleaning and drying specifically includes: The Ho2Fe 17 / Cu is taken out from the copper plating solution and cleaned with deionized water and alcohol, and then dried after cleaning.

[0015] The beneficial effects of the present invention are embodied in: 1. The present invention adopts Ho2Fe 17 The surface of the base powder particles is plated with copper to introduce Cu, forming a core-shell Ho2Fe 17 / Cu composite powder, and the Cu content can be controlled by the length of copper plating time, while the randomly oriented core-shell Ho2Fe 17 / Cu composite powder is formed by short-time vacuum hot pressing, which fundamentally avoids the formation of Ho2Fe 17 Based composite materials (such as Ho2Fe 17 / Fe bulk composite materials) have anisotropic properties, and generate Ho2Fe with isotropic zero thermal expansion properties 17Based composite materials (specifically Ho2Fe 17 / Cu bulk composite material), and under the action of copper immersion plating and short-time vacuum hot pressing treatment, dense Ho2Fe 17 / Cu bulk composite materials, in which Cu with excellent ductility is in the Ho2Fe 17 The matrix is ​​distributed in a continuous network. Moreover, since the mixing enthalpy between Cu and Ho (-22kJ / mol) is much smaller than the mixing enthalpy between Fe and Ho (-2kJ / mol), Cu and Ho2Fe 17 A reaction occurs at the interface between the two phases, generating alternating nano-layered α-Fe and HoCu4. This reaction layer has good plasticity and can hinder crack propagation, thereby effectively inhibiting crack propagation under external force, which is different from the Ho2Fe obtained by conventional arc melting. 17 Based composite materials (such as Ho2Fe 17 / Fe bulk composite material), the compressive strength is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the Ho2Fe after copper plating in the embodiment of the present invention. 17 X-ray diffraction pattern of / Cu composite powder; Figure 2 The Ho2Fe provided in the embodiment of the present invention 17 SEM images and element distribution maps of the Cu / Cu bulk composites; Figure 3 The Ho2Fe provided in the embodiment of the present invention 17 Thermal expansion performance diagram of / Cu bulk composite material; Figure 4 The conventional arc melting method is used to prepare Ho2Fe 17 Schematic diagram of thermal expansion curves of / Fe bulk composite materials in two perpendicular directions; Figure 5 The Ho2Fe obtained in Example 2 of the present invention 17 Schematic diagram of thermal expansion curves of / Cu bulk composite materials in different directions; Figure 6 The Ho2Fe provided in the embodiment of the present invention 17 Schematic diagram of the compressive stress-strain curve of the / Cu bulk composite material; Figure 7 It is a conventional arc melting method in the prior art. Figure 4 Ho2Fe 17 Schematic diagram of the mechanical properties of / Fe bulk composites; Figure 8 It is the Ho2Fe provided in Example 2 of the present invention17 Transmission electron microscopy images and element distribution maps of the / Cu bulk composites and Ho2Fe 17 Scanning electron microscope image of the / Cu bulk composite material after compression fracture; Figure 9 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0017] The present invention will now be described in further detail with reference to the accompanying drawings.

[0018] Combined with attachment Figure 9 As shown, a Ho2Fe 17 A method for preparing a zero thermal expansion composite material comprises the following steps: S1: Prepare Ho2Fe with particle size of 50-200 μm 17 Base powder, preferably, the Ho2Fe 17 Base powder selection Ho2Fe 17 / Cu particles are used as the original powder particles, with a particle size of 100-150 μm, and the Ho2Fe 17 The base powder is pre-treated by pickling, specifically, using hydrochloric acid alcohol solution to pickle the Ho2Fe 17 The base powder is pre-treated by pickling; S2: Prepare a copper plating solution, wherein the copper plating solution includes water, CuSO4·5H2O, C 10 H 14 N2Na2O8, K4[Fe(CN)6]·3H2O, HCHO, NaKC4H4O6·4H2O and C 10 H8N2, specifically, the concentration of the CuSO4·5H2O in the copper plating solution is 10-15g / L, the C 10 H 14 The concentration of N2Na2O8 in the copper plating solution is 15-20g / L, the concentration of K4[Fe(CN)6]·3H2O in the copper plating solution is 30-35mg / L, the concentration of HCHO in the copper plating solution is 5-7g / L, the concentration of NaKC4H4O6·4H2O in the copper plating solution is 10-15g / L, and the concentration of C 10 The concentration of H8N2 in the copper plating solution is 10-20 mg / L. 17 The base powder is suspended in the copper plating solution and immersed in the copper plating solution to form Ho2Fe 17 / Cu, wherein the Ho2Fe 17 The content of the base powder compared to the copper plating solution is 10-20 g / L, specifically, Ho2Fe 17The content of the base powder compared to the copper plating solution is Ho2Fe 17 The ratio between the weight of the base powder and the volume of the copper plating solution, the immersion plating temperature is 25°C-45°C, the immersion plating time is 120min-500min, preferably, the immersion plating time is 180min-300min, and the immersion plating temperature is 40°C; S3: The Ho2Fe 17 / Cu is taken out from the copper plating solution and cleaned and dried. Specifically, the Ho2Fe 17 / Cu was taken out from the copper plating solution and washed with deionized water and alcohol, and then dried to obtain core-shell Ho2Fe 17 / Cu composite powder material, wherein the core-shell structure is specifically a composite material structure consisting of an inner core and an outer cladding layer that completely encapsulates the inner core; S4: The core-shell Ho2Fe 17 The / Cu composite powder is placed in a vacuum hot pressing furnace for vacuum hot pressing to generate Ho2Fe with isotropic zero thermal expansion performance. 17 Based on zero thermal expansion composite materials, wherein the generated Ho2Fe 17 The zero thermal expansion composite material is a bulk composite material, and the isotropic zero thermal expansion performance is specifically manifested as the thermal expansion curves in the three directions of xyz in the coordinate system basically coincide and have a zero thermal expansion effect. The vacuum hot pressing treatment temperature is 950°C-1100°C, the vacuum hot pressing treatment pressure is 500MPa-3000MPa, and the vacuum hot pressing treatment time is 1min-4min. Preferably, the vacuum hot pressing treatment temperature is 1070°C, the vacuum hot pressing treatment pressure is 2000MPa, and the vacuum hot pressing treatment time is 2min.

[0019] Example 1: S1: Prepare Ho2Fe with a particle size of 100-150 μm 17 / Cu particles, and the use of hydrochloric acid alcohol solution to 17 / Cu particles were pretreated by pickling; S2: Prepare a copper plating solution, wherein the copper plating solution includes water, CuSO4·5H2O with a concentration of 15g / L, and C 10 H 14 N2Na2O8, 35 mg / L K4[Fe(CN)6]·3H2O, 5 g / L HCHO, 15 g / L NaKC4H4O6·4H2O, and 20 mg / L C 10 H8N2, the Ho2Fe 17The base powder is suspended in the copper plating solution and immersed in the copper plating solution to form Ho2Fe 17 / Cu, wherein the Ho2Fe 17 The content of the base powder relative to the copper plating solution is 20 g / L, the immersion plating temperature is 40° C., and the immersion plating time is 180 min; S3: The Ho2Fe 17 / Cu was taken out from the copper plating solution and washed and dried with hydrochloric acid alcohol solution to obtain core-shell Ho2Fe 17 / Cu composite powder material; S4: The core-shell Ho2Fe 17 The / Cu composite powder was placed in a vacuum hot pressing furnace for vacuum hot pressing to produce a φ10×5mm Ho2Fe with isotropic zero thermal expansion performance. 17 Based on zero thermal expansion composite materials, wherein the generated Ho2Fe 17 Zero thermal expansion composite material is Ho2Fe 17 / Cu bulk composite material, the vacuum hot pressing treatment temperature is 950°C, the vacuum hot pressing treatment pressure is 2000MPa, and the vacuum hot pressing treatment time is 4min.

[0020] Example 2:

[0021] S1: Prepare Ho2Fe with a particle size of 100-150 μm 17 / Cu particles, and the use of hydrochloric acid alcohol solution to 17 / Cu particles were pretreated by pickling; S2: Prepare a copper plating solution, wherein the copper plating solution includes water, CuSO4·5H2O with a concentration of 15g / L, and C 10 H 14 N2Na2O8, 35 mg / L K4[Fe(CN)6]·3H2O, 5 g / L HCHO, 15 g / L NaKC4H4O6·4H2O, and 20 mg / L C 10 H8N2, the Ho2Fe 17 The base powder is suspended in the copper plating solution and immersed in the copper plating solution to form Ho2Fe 17 / Cu, wherein the Ho2Fe 17 The content of the base powder relative to the copper plating solution is 20 g / L, the immersion plating temperature is 40° C., and the immersion plating time is 210 min; S3: The Ho2Fe 17 / Cu was taken out from the copper plating solution and washed and dried with hydrochloric acid alcohol solution to obtain core-shell Ho2Fe 17 / Cu composite powder material; S4: The core-shell Ho2Fe 17 The / Cu composite powder was placed in a vacuum hot pressing furnace for vacuum hot pressing to produce a φ10×5mm Ho2Fe with isotropic zero thermal expansion performance. 17 Based on zero thermal expansion composite materials, wherein the generated Ho2Fe 17 Zero thermal expansion composite material is Ho2Fe 17 / Cu bulk composite material, the vacuum hot pressing treatment temperature is 1100° C., the vacuum hot pressing treatment pressure is 3000 MPa, and the vacuum hot pressing treatment time is 2 min.

[0022] Example 3:

[0023] S1: Prepare Ho2Fe with a particle size of 100-150 μm 17 / Cu particles, and the use of hydrochloric acid alcohol solution to 17 / Cu particles were pretreated by pickling; S2: Prepare a copper plating solution, wherein the copper plating solution includes water, CuSO4·5H2O with a concentration of 15g / L, and C 10 H 14 N2Na2O8, 35 mg / L K4[Fe(CN)6]·3H2O, 5 g / L HCHO, 15 g / L NaKC4H4O6·4H2O, and 20 mg / L C 10 H8N2, the Ho2Fe 17 The base powder is suspended in the copper plating solution and immersed in the copper plating solution to form Ho2Fe 17 / Cu, wherein the Ho2Fe 17 The content of the base powder relative to the copper plating solution is 20 g / L, the immersion plating temperature is 40° C., and the immersion plating time is 300 min; S3: The core-shell Ho2Fe 17 / Cu was taken out from the copper plating solution and washed and dried with hydrochloric acid alcohol solution to obtain core-shell Ho2Fe 17 / Cu composite powder material; S4: The Ho2Fe 17 The / Cu composite powder was placed in a vacuum hot pressing furnace for vacuum hot pressing to produce a φ10×5mm Ho2Fe with isotropic zero thermal expansion performance. 17 Based on zero thermal expansion composite materials, wherein the generated Ho2Fe17 Zero thermal expansion composite material is Ho2Fe 17 / Cu bulk composite material, the vacuum hot pressing treatment temperature is 1000°C, the vacuum hot pressing treatment pressure is 1000MPa, and the vacuum hot pressing treatment time is 3min.

[0024] Example 4:

[0025] S1: Prepare Ho2Fe with a particle size of 100-150 μm 17 / Cu particles, and the use of hydrochloric acid alcohol solution to 17 / Cu particles were pretreated by pickling; S2: Prepare a copper plating solution, wherein the copper plating solution includes water, CuSO4·5H2O with a concentration of 15g / L, and C 10 H 14 N2Na2O8, 35 mg / L K4[Fe(CN)6]·3H2O, 5 g / L HCHO, 15 g / L NaKC4H4O6·4H2O, and 20 mg / L C 10 H8N2, the Ho2Fe 17 The base powder is suspended in the copper plating solution and immersed in the copper plating solution to form Ho2Fe 17 / Cu, wherein the Ho2Fe 17 The content of the base powder relative to the copper plating solution is 20 g / L, the immersion plating temperature is 40° C., and the immersion plating time is 1440 min; S3: The Ho2Fe 17 / Cu was taken out from the copper plating solution and washed and dried with hydrochloric acid alcohol solution to obtain core-shell Ho2Fe 17 / Cu composite powder material; S4: The core-shell Ho2Fe 17 The / Cu composite powder was placed in a vacuum hot pressing furnace for vacuum hot pressing to produce a φ10×5mm Ho2Fe with isotropic zero thermal expansion performance. 17 Based on zero thermal expansion composite materials, wherein the generated Ho2Fe 17 Zero thermal expansion composite material is Ho2Fe 17 / Cu bulk composite material, the vacuum hot pressing treatment temperature is 950°C, the vacuum hot pressing treatment pressure is 2000MPa, and the vacuum hot pressing treatment time is 2min.

[0026] The composite powder materials generated in Examples 1 to 4 were tested: Combined with attachment Figure 1As shown, a Bruker-AXS D8 Advance X-ray diffractometer was used to analyze the Ho2Fe 17 / Cu original powder and Ho2Fe obtained after copper plating 17 / Cu composite powder was subjected to X-ray diffraction analysis to generate Figure 1 The X-ray diffraction pattern shown in Figure 1 It can be observed that the 17 Compared with the original powder, the Ho2Fe 17 The X-ray diffraction pattern of the / Cu composite powder shows an obvious copper diffraction peak. This phenomenon shows that the Ho2Fe 17 Copper has been successfully deposited on the surface of the base powder. As the copper plating time increases from 180 min to 1440 min, the diffraction peak of copper gradually strengthens, indicating that the thickness of the copper layer increases with the increase of copper plating time.

[0027] Combined with attachment Figure 2 As shown, the Ho2Fe 17 / Cu bulk composite materials to carry out micromorphology and composition analysis, specifically Figure 2 As shown, Figure 2 (a) shows the Ho2Fe obtained in Example 1 17 Scanning electron micrograph of the Mg / Cu bulk composite material and the distribution of copper elements show that there are no obvious pores in the sample, the structure is dense, and copper is distributed in a continuous network. Figure 2 (b) shows the Ho2Fe obtained in Example 4 17 Scanning electron micrograph of the composite material and the distribution diagram of copper elements of the composite material of the present invention show that the thickness of the copper mesh is significantly increased compared with the sample obtained in Example 1, and the copper content in the composite material is increased. This is because the copper plating time in Example 4 is 1440 min, while the copper plating time in Example 1 is 180 min. Therefore, the copper content in Example 4 is 0.0447 W / m. 17 / CMore copper is introduced into the surface of the original powder, which is consistent with Figure 1 The structure is consistent, so the final generated Ho2Fe can be regulated by controlling the copper plating time. 17 / Cu bulk composite material.

[0028] Combined with attachment Figure 3 As shown, the Ho2Fe 17 The thermal expansion performance of the Cu / Cu bulk composite material was characterized. Figure 3 As shown, the Ho2Fe obtained in Example 1 17The linear thermal expansion coefficient of the / Cu bulk composite material is -1.69×10 −6 K −1 , showing zero thermal expansion effect, wherein the temperature range of 120~352 K is the temperature range of the main use environment of the material, and the Ho2Fe obtained in Examples 2 and 3 17 The linear thermal expansion coefficients of the / Cu bulk composites in the temperature range of 120~352 K are -0.21×10 −6 K −1 and 1.73×10 −6 K −1 , still showing zero thermal expansion effect, wherein the temperature range of 120~352 K is the temperature range of the main use environment of the material, the Ho2Fe obtained in Example 4 17 The linear thermal expansion coefficient of the / Cu bulk composite material is 3.01×10 −6 K −1 , showing a positive thermal expansion effect, wherein the temperature range of 120~352 K is the temperature range of the main use environment of the material. It can be seen that with the increase of copper plating time (the copper plating time of Examples 1, 2, 3 and 4 is 180min, 210min, 300min and 1440min respectively), Ho2Fe 17 / Cu bulk composites, the Cu content increases, and the Ho2Fe 17 / Cu bulk composites show a transition from zero thermal expansion to positive thermal expansion effect. The above change in thermal expansion behavior comes from the 17 The matrix phase and the Cu phase have different thermal expansion characteristics. The elemental Cu exhibits positive thermal expansion, while Ho2Fe 17 The matrix exhibits a negative thermal expansion effect, which can compensate for Ho2Fe when the Cu content is low. 17 The negative thermal expansion effect of the matrix makes Ho2Fe 17 The Ho2Fe / Cu bulk composite material exhibits zero thermal expansion effect as a whole. When the Cu content is high, the positive thermal expansion effect of Cu dominates, making the Ho2Fe 17 / Cu bulk composite material exhibits a positive thermal expansion effect as a whole.

[0029] Combined with attachment Figure 4 As shown, the conventional arc melting method for preparing Ho2Fe 17 The thermal expansion curves of the Ho2Fe bulk composite material in two perpendicular directions show that in the temperature range of 100~355 K, there is a significant difference in the thermal expansion coefficient of the material along the two mutually perpendicular directions. 17The thermal expansion coefficients of the / Fe bulk composite material along two mutually perpendicular directions are 0.19×10 −6 K −1 and 6.91×10 −6 K −1 ,according to Figure 4 From the curve characteristics of (a) and 4(b), it can be seen that in the temperature range of 120~352K, the thermal expansion coefficient of the material along two mutually perpendicular directions has obvious differences, showing significant anisotropic thermal expansion properties; Combined with attachment Figure 5 As shown, Figure 5 The Ho2Fe obtained in Example 2 is shown 17 The thermal expansion curves of the Cu / Cu bulk composite material in different directions are shown in Figure 2. The thermal expansion curves of the three directions in the coordinate system are almost identical. In the working temperature range of 120~352K, the thermal expansion coefficients of the three directions are -0.27×10 −6 K −1 、-0.36×10 −6 K −1 and -0.21×10 −6 K −1 , the thermal expansion coefficient is relatively close, showing an isotropic zero thermal expansion effect. Figure 4 With attached Figure 5 Comparing the contents shown, compared with the existing preparation technology, the present invention can obtain the beneficial effect of isotropic thermal expansion effect.

[0030] Combined with attachment Figure 6 As shown, the Ho2Fe 17 The mechanical properties of the composite material were tested. The specific results are as follows: Figure 6 As shown in the (compressive stress-strain curve), the results show that the Ho2Fe 17 The maximum compressive strengths of the / Cu bulk composites are 1256MPa, 1417MPa, 1704MPa and 1810MPa, respectively; Combined with attachment Figure 7 As shown, it shows that conventional arc melting is used in the prior art to prepare Figure 4 Ho2Fe 17 The mechanical properties of the Ho2Fe / Fe bulk composite material were tested and the compressive strength value was 800MPa. Compared with the above-mentioned existing preparation technology, the present invention prepared Ho2Fe with significantly improved compressive strength by chemical copper plating and short-time vacuum hot pressing. 17 Based composite materials, specifically Ho2Fe 17 / Cu bulk composite materials.

[0031] Combined with attachment Figure 8 As shown, the Ho2Fe 17 / Cu bulk composite materials, and carried out nano-scale structure and composition analysis. The results are as follows Figure 6 As shown in (ad), it can be seen from the figure that Ho2Fe 17 A transition layer is formed at the interface between the main phase and Cu. The transition layer is composed of alternating nano-layered α-Fe and HoCu4. The Ho2Fe 17 The micromorphology of the / Cu bulk composite material after compression fracture was analyzed. Figure 6 (e) As shown in the figure, the sample is under compressive stress. 17 Cracks were generated in the main phase, but the crack propagation was hindered by the reaction layer. It can be seen that the copper plating and vacuum hot pressing treatment can effectively reduce the Ho2Fe 17 A unique reaction layer is formed at the interface between the two phases with Cu, which hinders crack propagation and produces Ho2Fe with improved compressive strength. 17 / Cu bulk composite materials.

[0032] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions in the specification are only preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention as claimed. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A type of Ho2Fe 17 A method for preparing a zero thermal expansion composite material comprises the following steps, characterized in that: S1: Prepare Ho2Fe with particle size of 50-200 μm 17 Base powder, and the Ho2Fe 17 The base powder is pre-treated by pickling; S2: prepare copper plating solution, and add the Ho2Fe 17 The base powder is suspended in the copper plating solution and immersed in the copper plating solution to form Ho2Fe 17 / Cu, wherein the Ho2Fe 17 The content of the base powder relative to the copper plating solution is 10-20 g / L, the immersion plating temperature is 25° C.-45° C., and the immersion plating time is 120 min-500 min; S3: The Ho2Fe 17 / Cu is taken out from the copper plating solution, cleaned and dried to obtain core-shell Ho2Fe 17 / Cu composite powder material; S4: The core-shell Ho2Fe 17 The / Cu composite powder is placed in a vacuum hot pressing furnace for vacuum hot pressing to generate Ho2Fe with isotropic zero thermal expansion performance. 17 The zero thermal expansion composite material is prepared, wherein the vacuum hot pressing treatment temperature is 950° C.-1100° C., the vacuum hot pressing treatment pressure is 500 MPa-3000 MPa, and the vacuum hot pressing treatment time is 1 min-4 min.

2. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: The immersion plating treatment time is 180 min-300 min.

3. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: The immersion plating temperature is 40°C.

4. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: The copper plating solution includes water, CuSO4·5H2O, C 10 H 14 N2Na2O8, K4[Fe(CN)6]·3H2O, HCHO, NaKC4H4O6·4H2O and C 10 H8N2.

5. A Ho2Fe according to claim 4 17 The method for preparing a zero thermal expansion composite material is characterized by: The concentration of CuSO4·5H2O in the copper plating solution is 10-15g / L. 10 H 14 The concentration of N2Na2O8 in the copper plating solution is 15-20g / L, the concentration of K4[Fe(CN)6]·3H2O in the copper plating solution is 30-35mg / L, the concentration of HCHO in the copper plating solution is 5-7g / L, the concentration of NaKC4H4O6·4H2O in the copper plating solution is 10-15g / L, and the concentration of C 10 The concentration of H8N2 in the copper plating solution is 10-20 mg / L.

6. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: The vacuum hot pressing treatment time is 2 minutes.

7. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: The vacuum hot pressing treatment temperature is 1070° C., and the vacuum hot pressing treatment pressure is 2000 MPa.

8. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: Prepare Ho2Fe with a particle size of 100-150 μm 17 Base powder.

9. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: The S1 and the Ho2Fe 17 The acid washing pretreatment of the base powder specifically includes: The Ho2Fe 17 The base powder is pre-treated by pickling.

10. A Ho2Fe according to claim 1 17 The method for preparing a zero thermal expansion composite material is characterized by: The S3 contains the Ho2Fe 17 Taking out / Cu from the copper plating solution for cleaning and drying specifically includes: The Ho2Fe 17 / Cu is taken out from the copper plating solution and cleaned with deionized water and alcohol, and then dried after cleaning.

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