Metal mass block with near-zero magnetic susceptibility and preparation method thereof

Abstract

The invention discloses a metal mass block with near-zero magnetic susceptibility and a preparation method thereof, and belongs to the field of gravitational wave detection. The invention aims to solve the problems that the magnetic susceptibility of the existing quality inspection material is still high, and the price of the used noble metal alloy is high. The metal mass block with the near-zero magnetic susceptibility is an AuPt precious metal mass block, an AuIr precious metal mass block or a CuAl non-precious metal mass block. The preparation method comprises the following steps: 1, weighing; and 2, smelting the alloy by adopting a vacuum precision suspension smelting furnace. The invention is used for the near-zero magnetic susceptibility metal mass block and the preparation thereof.

Description

Technical Field

[0001] The present invention belongs to the field of gravitational wave detection. Background Art

[0002] The detection of gravitational waves in space will open a new window in the 0.1 MHz to 1 Hz frequency band, undetectable from the ground. This will enable the in-depth study of massive black holes using gravitational waves, which is of great significance for humanity's comprehensive understanding of the universe. Ultra-high-sensitivity inertial sensors are a key component of space gravitational wave detection. They use high-precision interstellar laser ranging to record the distance changes between individual test mass probes, thereby providing information about gravitational waves. The remanent magnetization of the test mass material determines the magnetic perturbations experienced by the inertial sensor in space environments, and its design must meet the requirement for near-zero remanence. Au-Pt alloys are currently a commonly used test mass material, but their near-zero magnetic susceptibility values ​​still struggle to meet operational requirements. Furthermore, the precious metal alloys used are expensive, making the development of non-precious metal alloys with near-zero magnetic susceptibility urgent. Summary of the Invention

[0003] The present invention aims to solve the problem that the magnetic susceptibility of existing inspection mass materials is still relatively high and the precious metal alloys used are expensive, and further provides a metal mass with near-zero magnetic susceptibility and a preparation method thereof.

[0004] A metal mass block with near-zero magnetic susceptibility, wherein the metal mass block with near-zero magnetic susceptibility is an AuPt noble metal mass block, an AuIr noble metal mass block, or a CuAl non-noble metal mass block; The AuPt noble metal mass block is prepared from 24% to 24.5% Pt and the remainder Au according to mass percentage; The AuIr precious metal mass block is prepared by 22.5% to 23% Ir and the remainder Au according to mass percentage; The CuAl non-precious metal mass block is prepared from 29% to 29.5% Al and the remainder Cu in terms of mass percentage.

[0005] The method for preparing a metal mass block with near-zero magnetic susceptibility is carried out in the following steps: 1. Weigh: Weigh the metal raw materials according to the mass percentage of the AuPt noble metal mass block, the AuIr noble metal mass block or the CuAl non-noble metal mass block; The AuPt noble metal mass block is composed of 24% to 24.5% Pt and the remainder Au, and Pt metal particles and Au metal particles are weighed; The AuIr precious metal mass block is weighed to obtain Ir metal particles and Au metal particles according to the mass percentage of Ir of 22.5% to 23% and the balance of Au; The CuAl non-precious metal mass block is prepared by weighing Al metal particles and Cu metal particles according to a mass percentage of 29% to 29.5% Al and the balance Cu; 2. Use vacuum precision suspension melting furnace to melt the alloy: The metal raw materials are fed into the suspension zone of the vacuum precision suspension melting furnace one by one, and then the melting chamber is sealed, the melting chamber is evacuated, and then filled with high-purity argon gas to a vacuum degree of 0.3Pa~0.5Pa. Under the conditions of vacuum degree of 0.3Pa~0.5Pa and low power of 3kW~5kW, it is preheated to a temperature of 1000℃~1200℃, and degassed at a temperature of 1000℃~1200℃ for 5min~8min, and then under the conditions of vacuum degree of 0.3Pa~0.5Pa and low power of 3kW~5kW, The temperature is raised to 1350°C~2400°C, and the metal raw material is heated at a temperature of 1350°C~2400°C until it is completely melted to obtain a melt. Under the conditions of a vacuum degree of 0.3Pa~0.5Pa, a temperature of 1350°C~2400°C, an axial magnetic field of 0.4T~0.5T and an argon flow rate of 0.5L / min~1L / min, the melt is suspended for 8min~10min. After the smelting is completed, the power is turned off, and the alloy freely falls into a water-cooled copper mold for rapid cooling to obtain a metal mass block with near-zero magnetic susceptibility.

[0006] The beneficial effects of the present invention are: 1. The magnetic susceptibility of the metal mass block with near-zero magnetic susceptibility of the present invention is 2×10 -8 m 3 / Kg to -2×10 -8 m 3 / Kg, and at a given space environment operating temperature of 294.5K, the optimal mass magnetic susceptibility value can be as low as 2.59507×10 -11 m 3 / Kg, the magnetic susceptibility decreases significantly and tends to zero.

[0007] 2. Considering density and element stability, the present invention selects Ir element to replace Pt, and provides another design scheme for near-zero magnetic susceptibility precious metal mass alloy material.

[0008] 3. Based on the design concept of paramagnetic elements-diamagnetic elements-magnetic susceptibility tending to zero, the present invention selects Cu and Al elements to replace precious metals, which greatly reduces costs.

[0009] The invention relates to a metal mass block with near-zero magnetic susceptibility and a preparation method thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1The magnetic susceptibility experimental results of the Au:Pt-75.87:24.13wt% mass alloy material prepared in Example 1; Figure 2 The magnetic susceptibility experimental results of the Au:Ir-77.32:22.68wt% mass alloy material prepared in Example 2; Figure 3 These are the experimental results of the magnetic susceptibility of the Cu:Al-70.57:29.43wt% mass alloy material prepared in Example 3. DETAILED DESCRIPTION

[0011] Specific embodiment 1: In this embodiment, the metal mass block with near-zero magnetic susceptibility is an AuPt noble metal mass block, an AuIr noble metal mass block or a CuAl non-noble metal mass block; The AuPt noble metal mass block is prepared from 24% to 24.5% Pt and the remainder Au according to mass percentage; The AuIr precious metal mass block is prepared by 22.5% to 23% Ir and the remainder Au according to mass percentage; The CuAl non-precious metal mass block is prepared from 29% to 29.5% Al and the remainder Cu in terms of mass percentage.

[0012] The beneficial effects of this embodiment are: 1. The magnetic susceptibility of the metal mass block with near-zero magnetic susceptibility in this embodiment is 2×10 -8 m 3 / Kg to -2×10 -8 m 3 / Kg, and at a given space environment operating temperature of 294.5K, the optimal mass magnetic susceptibility value can be as low as 2.59507×10 -11 m 3 / Kg, the magnetic susceptibility decreases significantly and tends to zero.

[0013] 2. In consideration of density and element stability, this embodiment selects Ir element to replace Pt, providing another design scheme for near-zero magnetic susceptibility noble metal mass alloy material.

[0014] 3. This embodiment adopts the design concept of paramagnetic element-diamagnetic element-magnetic susceptibility tending to zero, and selects Cu and Al elements to replace precious metals, which greatly reduces costs.

[0015] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the AuPt noble metal mass block is made of 24.13% Pt and the remainder Au by mass. Other aspects are the same as specific embodiment 1.

[0016] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that the AuIr precious metal mass block is made of 22.68% Ir and the remainder Au by mass. Other aspects are the same as specific embodiment 1 or 2.

[0017] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the CuAl non-precious metal mass block is made of 29.43% Al and the remainder Cu by mass. Other aspects are the same as specific embodiments 1 to 3.

[0018] Specific embodiment 5: The method for preparing a metal mass block with near-zero magnetic susceptibility in this embodiment is carried out according to the following steps: 1. Weigh: Weigh the metal raw materials according to the mass percentage of the AuPt noble metal mass block, the AuIr noble metal mass block or the CuAl non-noble metal mass block; The AuPt noble metal mass block is composed of 24% to 24.5% Pt and the remainder Au, and Pt metal particles and Au metal particles are weighed; The AuIr precious metal mass block is weighed to obtain Ir metal particles and Au metal particles according to the mass percentage of Ir of 22.5% to 23% and the balance of Au; The CuAl non-precious metal mass block is prepared by weighing Al metal particles and Cu metal particles according to a mass percentage of 29% to 29.5% Al and the balance Cu; 2. Use vacuum precision suspension melting furnace to melt the alloy: The metal raw materials are fed into the suspension zone of the vacuum precision suspension melting furnace one by one, and then the melting chamber is sealed, the melting chamber is evacuated, and then filled with high-purity argon gas to a vacuum degree of 0.3Pa~0.5Pa. Under the conditions of vacuum degree of 0.3Pa~0.5Pa and low power of 3kW~5kW, it is preheated to a temperature of 1000℃~1200℃, and degassed at a temperature of 1000℃~1200℃ for 5min~8min, and then under the conditions of vacuum degree of 0.3Pa~0.5Pa and low power of 3kW~5kW, The temperature is raised to 1350°C~2400°C, and the metal raw material is heated at a temperature of 1350°C~2400°C until it is completely melted to obtain a melt. Under the conditions of a vacuum degree of 0.3Pa~0.5Pa, a temperature of 1350°C~2400°C, an axial magnetic field of 0.4T~0.5T and an argon flow rate of 0.5L / min~1L / min, the melt is suspended for 8min~10min. After the smelting is completed, the power is turned off, and the alloy freely falls into a water-cooled copper mold for rapid cooling to obtain a metal mass block with near-zero magnetic susceptibility.

[0019] Specific embodiment 6: This embodiment differs from specific embodiment 5 in that the metal raw material in step 1 is pre-treated metal element particles. Other aspects are the same as specific embodiment 5.

[0020] Specific embodiment 7: This embodiment differs from either specific embodiment 5 or 6 in that: the purity of the Pt metal particles described in step 1 is 99.999%; the purity of the Ir metal particles described in step 1 is 99.99%; and the purity of the Au metal particles described in step 1 is 99.9995% to 99.9999%. Other aspects are the same as specific embodiments 5 or 6.

[0021] Specific embodiment 8: This embodiment differs from Specific embodiments 5 to 7 in that the purity of the Al metal particles in step 1 is 99.999%; the purity of the Cu metal particles in step 1 is 99.999%. Other aspects are the same as Specific embodiments 5 to 7.

[0022] Specific embodiment 9: This embodiment differs from any one of specific embodiments 5 to 8 in that: in step 2, the smelting chamber is vacuumed to 5×10 -4 Pa~6×10 -4 Pa. The rest is the same as the specific embodiments 5 to 8.

[0023] Specific embodiment 10: This embodiment differs from any one of specific embodiments 5 to 9 in that, in step 2, high-purity argon gas is subsequently introduced at a flow rate of 0.5 L / min to 1 L / min until the vacuum reaches 0.3 Pa to 0.5 Pa; the purity of the high-purity argon gas is ≥ 99.99%. Other steps are the same as specific embodiments 5 to 9.

[0024] The following examples are used to verify the beneficial effects of the present invention: Example 1: A metal mass block with near-zero magnetic susceptibility, wherein the metal mass block with near-zero magnetic susceptibility is an AuPt noble metal mass block; The AuPt noble metal mass block is prepared by 24.13% Pt and the balance Au according to mass percentage, and is named Au:Pt-75.87:24.13wt% mass block alloy material; The method for preparing the metal mass block with near-zero magnetic susceptibility is carried out according to the following steps: 1. Weigh: Weigh Pt metal particles and Au metal particles according to the mass percentage of 24.13% Pt and the balance Au; 2. Use vacuum precision suspension melting furnace to melt the alloy: The metal raw materials are fed into the suspension zone of the vacuum precision suspension melting furnace one by one, and then the melting chamber is sealed and vacuumed to 5×10 -4 Pa, then, under the condition of an argon flow rate of 0.5L / min, high-purity argon gas is filled to a vacuum degree of 0.5Pa, under the conditions of a vacuum degree of 0.5Pa and a low power of 5kW, it is preheated to a temperature of 1200°C, and degassed at a temperature of 1200°C for 5 minutes, then under the conditions of a vacuum degree of 0.5Pa and a low power of 5kW, the temperature is raised to 1850°C, and under the conditions of a temperature of 1850°C, the metal raw material is heated until it is completely melted to obtain a melt, and under the conditions of a vacuum degree of 0.5Pa, a temperature of 1850°C, an axial magnetic field of 0.5T and an argon flow rate of 1L / min, the melt is suspended for 8 minutes. After the smelting is completed, the power is turned off, and the alloy freely falls into a water-cooled copper mold for rapid cooling to obtain a metal mass block with near-zero magnetic susceptibility; the purity of the high-purity argon gas is 99.99%.

[0025] The purity of the Pt metal particles described in step 1 is 99.999%; the purity of the Au metal particles described is 99.9995%.

[0026] The Pt metal element particle pretreatment is specifically carried out according to the following steps: immersing in 10% by mass hot HCl for 30 seconds at a temperature of 80°C to remove surface oxides, then ultrasonically cleaning with ultrapure water and anhydrous ethanol alternately at a power of 100W, each cleaning for 10 minutes, and after cleaning, high-temperature annealing for 1.5 hours in a hydrogen atmosphere at a temperature of 800°C to eliminate internal stress and remove adsorbed gases.

[0027] The Au metal element particle pretreatment is specifically carried out according to the following steps: immersing in dilute aqua regia for 30 seconds at a temperature of 25°C to remove surface oxides, then ultrasonically cleaning with ultrapure water and anhydrous ethanol alternately at a power of 100W, each cleaning for 10 minutes, and after cleaning, high-temperature annealing for 1.5 hours in a hydrogen atmosphere at a temperature of 600°C to eliminate internal stress and remove adsorbed gases; the dilute aqua regia is a mixture of 37% by mass HCl and 65% by mass HNO3 in a volume ratio of 3:1.

[0028] Example 2: A metal mass block with near-zero magnetic susceptibility, wherein the metal mass block with near-zero magnetic susceptibility is an AuIr noble metal mass block; The AuIr precious metal mass block is prepared by 22.68% Ir and the balance Au according to mass percentage, and is named Au:Ir-77.32:22.68wt% mass block alloy material; The method for preparing the metal mass block with near-zero magnetic susceptibility is carried out according to the following steps: 1. Weigh: Weigh Ir and Au metal particles in a ratio of 22.68% by mass of Ir and the remainder of Au; 2. Use vacuum precision suspension melting furnace to melt the alloy: The metal raw materials are fed into the suspension zone of the vacuum precision suspension melting furnace one by one, and then the melting chamber is sealed and vacuumed to 5×10 -4 Pa, then under the condition of argon flow rate of 0.5L / min, high-purity argon gas is filled to the vacuum degree of 0.5Pa, under the conditions of vacuum degree of 0.5Pa and low power of 5kW, it is preheated to a temperature of 1200℃, and degassed at the temperature of 1200℃ for 5min, then under the conditions of vacuum degree of 0.5Pa and low power of 5kW, the temperature is raised to 2400℃, and under the condition of temperature of 2400℃, the metal raw material is heated until it is completely melted to obtain a melt, and under the conditions of vacuum degree of 0.5Pa, temperature of 2400℃, axial magnetic field of 0.5T and argon flow rate of 1L / min, the melt is suspended for 8min. After the smelting is completed, the power is turned off, and the alloy freely falls into a water-cooled copper mold for rapid cooling to obtain a metal mass block with near-zero magnetic susceptibility; the purity of the high-purity argon gas is 99.99%.

[0029] The purity of the Ir metal particles described in step 1 is 99.99%; the purity of the Au metal particles described is 99.9995%.

[0030] The Ir metal element particle pretreatment is specifically carried out according to the following steps: immersing in 10% by mass hot HCl for 30 seconds at a temperature of 80°C to remove surface oxides, then ultrasonically cleaning with ultrapure water and anhydrous ethanol alternately at a power of 100W, each cleaning for 10 minutes, and after cleaning, high-temperature annealing for 1.5 hours in a hydrogen atmosphere at a temperature of 1000°C to eliminate internal stress and remove adsorbed gases.

[0031] The Au metal element particle pretreatment is specifically carried out according to the following steps: immersing in dilute aqua regia for 30 seconds at a temperature of 25°C to remove surface oxides, then ultrasonically cleaning with ultrapure water and anhydrous ethanol alternately at a power of 100W, each cleaning for 10 minutes, and after cleaning, high-temperature annealing for 1.5 hours in a hydrogen atmosphere at a temperature of 600°C to eliminate internal stress and remove adsorbed gases; the dilute aqua regia is a mixture of 37% by mass HCl and 65% by mass HNO3 in a volume ratio of 3:1.

[0032] Example 3: A metal mass block with near-zero magnetic susceptibility, wherein the metal mass block with near-zero magnetic susceptibility is a CuAl non-precious metal mass block; The CuAl non-precious metal mass block is prepared by 29.43% Al and the balance Cu according to mass percentage, and is named Cu:Al-70.57:29.43wt% mass block alloy material; The method for preparing the metal mass block with near-zero magnetic susceptibility is carried out according to the following steps: 1. Weigh: Al metal particles and Cu metal particles are weighed according to the mass percentage of 29.43% Al and the balance Cu; 2. Use vacuum precision suspension melting furnace to melt the alloy: The metal raw materials are fed into the suspension zone of the vacuum precision suspension melting furnace one by one, and then the melting chamber is sealed and vacuumed to 5×10 -4 Pa, then under the condition of argon flow rate of 0.5L / min, high-purity argon gas is filled to the vacuum degree of 0.5Pa, under the conditions of vacuum degree of 0.5Pa and low power of 5kW, it is preheated to a temperature of 1200℃, and degassed at the temperature of 1200℃ for 5min, then under the conditions of vacuum degree of 0.5Pa and low power of 5kW, the temperature is raised to 1350℃, and under the condition of temperature of 1350℃, the metal raw material is heated until it is completely melted to obtain a melt, and under the conditions of vacuum degree of 0.5Pa, temperature of 1350℃, axial magnetic field of 0.5T and argon flow rate of 1L / min, the melt is suspended for 8min. After the smelting is completed, the power is turned off, and the alloy freely falls into a water-cooled copper mold for rapid cooling to obtain a metal mass block with near-zero magnetic susceptibility; the purity of the high-purity argon gas is 99.99%.

[0033] The purity of the Al metal particles in step 1 is 99.999%; the purity of the Cu metal particles is 99.999%; The Al metal element particle pretreatment is specifically carried out according to the following steps: immersing in 5% by mass NaOH for 2 minutes at a temperature of 55°C, then immersing in 30% by mass HNO3 for 30 seconds at a temperature of 25°C, and then ultrasonically cleaning with ultrapure water and anhydrous ethanol alternately at a power of 100W, each cleaning for 10 minutes, and finally heating and drying.

[0034] The Cu metal element particle pretreatment is specifically carried out according to the following steps: immersing in 10% by mass HNO3 for 30 seconds at a temperature of 25°C, then ultrasonically cleaning with ultrapure water and anhydrous ethanol alternately at a power of 100W, each cleaning for 10 minutes, and finally heating and drying.

[0035] The mass magnetic susceptibility variation with temperature was tested and analyzed for the mass block alloy materials of Examples 1 to 3.

[0036] Figure 1 The magnetic susceptibility experimental results of the Au:Pt-75.87:24.13wt% mass alloy material prepared in Example 1 are shown in the figure. As can be seen from the figure, the magnetic susceptibility of the alloy decreases with temperature fluctuation around the zero axis. - m 3 / Kg to -1×10 -8 m 3 / Kg, at a given space environment operating temperature of 294.5K, its mass magnetic susceptibility is 2.59507×10 -11 m 3 / Kg, tends to zero.

[0037] Figure 2 The magnetic susceptibility experimental results of the Au:Ir-77.32:22.68wt% mass alloy material prepared in Example 2 are shown in the figure. As can be seen from the figure, the magnetic susceptibility of the alloy is basically stable near the zero axis with temperature. -8 m 3 / Kg to -1×10 -8 m 3 / Kg, and at a given space environment operating temperature of 294.5K, its mass magnetic susceptibility is 4.193×10 -9 m 3 / Kg, the zero-axis discreteness and variation range of its magnetic susceptibility are close to those of the Au:Pt-75.87:24.13 wt% mass block alloy material designed in Example 1. Although the magnetic susceptibility at 294.5K is slightly higher, the Ir element has a higher density than Pt and is more chemically stable.

[0038] Figure 3 The magnetic susceptibility experimental results of the Cu:Al-70.57:29.43wt% mass alloy material prepared in Example 3 are shown in the figure. As can be seen from the figure, its magnetic susceptibility gradually increases with temperature. At 1×10 -8 m 3 / Kg to -2×10 -8 m 3 / Kg, and at a given space environment operating temperature of 294.5K, its mass magnetic susceptibility is 1.41×10 -9 m 3 / Kg, Cu and Al elements are easily oxidized, and their chemical stability is weaker than that of precious metal elements, but their cost has a great advantage.

Claims

1. A metal mass with near-zero magnetic susceptibility, characterized by The metal mass block with near-zero magnetic susceptibility is an AuPt noble metal mass block, an AuIr noble metal mass block or a CuAl non-noble metal mass block; The AuPt noble metal mass block is prepared from 24% to 24.5% Pt and the remainder Au according to mass percentage; The AuIr precious metal mass block is prepared by 22.5% to 23% Ir and the remainder Au according to mass percentage; The CuAl non-precious metal mass block is prepared from 29% to 29.5% Al and the remainder Cu in terms of mass percentage.

2. The metal mass with near-zero magnetic susceptibility according to claim 1, characterized in that The AuPt noble metal mass block is prepared from 24.13% Pt and the remainder Au in terms of mass percentage.

3. The metal mass with near-zero magnetic susceptibility according to claim 1, characterized in that The AuIr noble metal mass block is prepared from 22.68% Ir and the remainder Au in terms of mass percentage.

4. The metal mass with near-zero magnetic susceptibility according to claim 1, characterized in that The CuAl non-precious metal mass block is prepared from 29.43% Al and the remainder Cu in terms of mass percentage.

5. The method for preparing a metal mass block with near-zero magnetic susceptibility according to claim 1, characterized in that It is carried out in the following steps:

1. Weigh: Weigh the metal raw materials according to the mass percentage of the AuPt noble metal mass block, the AuIr noble metal mass block or the CuAl non-noble metal mass block; The AuPt noble metal mass block is composed of 24% to 24.5% Pt and the remainder Au, and Pt metal particles and Au metal particles are weighed; The AuIr precious metal mass block is weighed to obtain Ir metal particles and Au metal particles according to the mass percentage of Ir of 22.5% to 23% and the balance of Au; The CuAl non-precious metal mass block is prepared by weighing Al metal particles and Cu metal particles according to a mass percentage of 29% to 29.5% Al and the balance Cu; 2. Use vacuum precision suspension melting furnace to melt the alloy: The metal raw materials are fed into the suspension zone of the vacuum precision suspension melting furnace one by one, and then the melting chamber is sealed, the melting chamber is evacuated, and then filled with high-purity argon gas to a vacuum degree of 0.3Pa~0.5Pa. Under the conditions of vacuum degree of 0.3Pa~0.5Pa and low power of 3kW~5kW, it is preheated to a temperature of 1000℃~1200℃, and degassed at a temperature of 1000℃~1200℃ for 5min~8min, and then under the conditions of vacuum degree of 0.3Pa~0.5Pa and low power of 3kW~5kW, The temperature is raised to 1350°C~2400°C, and the metal raw material is heated at a temperature of 1350°C~2400°C until it is completely melted to obtain a melt. Under the conditions of a vacuum degree of 0.3Pa~0.5Pa, a temperature of 1350°C~2400°C, an axial magnetic field of 0.4T~0.5T and an argon flow rate of 0.5L / min~1L / min, the melt is suspended for 8min~10min. After the smelting is completed, the power is turned off, and the alloy freely falls into a water-cooled copper mold for rapid cooling to obtain a metal mass block with near-zero magnetic susceptibility.

6. The method for preparing a metal mass block with near-zero magnetic susceptibility according to claim 5, characterized in that The metal raw material described in step 1 is pre-treated metal element particles.

7. The method for preparing a metal mass block with near-zero magnetic susceptibility according to claim 5, characterized in that The purity of the Pt metal particles described in step 1 is 99.999%; the purity of the Ir metal particles described in step 1 is 99.99%; and the purity of the Au metal particles described in step 1 is 99.9995% to 99.9999%.

8. The method for preparing a metal mass block with near-zero magnetic susceptibility according to claim 5, characterized in that The purity of the Al metal particles described in step 1 is 99.999%; the purity of the Cu metal particles described in step 1 is 99.999%.

9. The method for preparing a metal mass block with near-zero magnetic susceptibility according to claim 5, characterized in that In step 2, the melting chamber is vacuumed to 5×10 -4 Pa~6×10 -4 Pa.

10. The method for preparing a metal mass block with near-zero magnetic susceptibility according to claim 5, characterized in that In step 2, high-purity argon gas is then introduced at an argon flow rate of 0.5 L / min to 1 L / min until the vacuum degree is 0.3 Pa to 0.5 Pa; the purity of the high-purity argon gas is ≥99.99%.

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