WO2023025280A1 - 一种Fe基球形屏蔽合金粉末及其制备方法 - Google Patents

一种Fe基球形屏蔽合金粉末及其制备方法 Download PDF

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WO2023025280A1
WO2023025280A1 PCT/CN2022/115085 CN2022115085W WO2023025280A1 WO 2023025280 A1 WO2023025280 A1 WO 2023025280A1 CN 2022115085 W CN2022115085 W CN 2022115085W WO 2023025280 A1 WO2023025280 A1 WO 2023025280A1
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alloy powder
alloy
powder
based spherical
shielding
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PCT/CN2022/115085
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English (en)
French (fr)
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刘颖
李军
孙伦高
陈康为
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四川大学
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F1/00—Shielding characterised by the composition of the materials
    • G21F1/02—Selection of uniform shielding materials
    • G21F1/08—Metals; Alloys; Cermets, i.e. sintered mixtures of ceramics and metals
    • G21F1/085—Heavy metals or alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
    • B22F2009/043—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by ball milling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F9/00—Making metallic powder or suspensions thereof
    • B22F9/02—Making metallic powder or suspensions thereof using physical processes
    • B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
    • B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
    • B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
    • B22F2009/0848—Melting process before atomisation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • the invention relates to the field of nuclear radiation shielding materials, in particular to an Fe-based spherical shielding alloy powder and a preparation method thereof.
  • Nuclear energy is a clean energy with stable structure and high energy density, and it is a beneficial supplement to human energy supply.
  • the reactor is the core part.
  • nuclear fission or fusion
  • Air, soil, water and food, etc. indirectly cause damage to the human body.
  • After a certain dose of radiation enters the human body it will ionize the tissues of the human body, resulting in cell deformation, tissue damage, and diseases such as organ dysfunction and metabolic disorders.
  • structural materials and machinery and equipment will be heated and activated, reducing their lifespan. Therefore, it is necessary to effectively shield the radiation produced by nuclear reactors.
  • the large-scale shielding structure in the current nuclear reactor is difficult to be integrally formed, and the widely used welding processing method will inevitably produce a large number of special-shaped areas, which will become weak areas of radiation shielding and pose a threat to the safety of personnel and equipment.
  • powders with good fluidity, high sphericity, and excellent comprehensive shielding performance are mainly used to densely fill the heterogeneous regions to make up for the lack of shielding performance of the main body and improve the shielding performance of the shielding body.
  • some large-scale Fe-based shielding materials will be partially worn or corroded during use, resulting in a decrease in the shielding performance of the shielding body. Filling and patching, thereby substantially reducing shielding system maintenance and repair costs.
  • boron-containing stainless steel powder prepared by gas atomization method, which has the advantages of high sphericity, good fluidity, good thermal neutron shielding performance and corrosion resistance. But it also has some disadvantages: in the boron-containing stainless steel powder, the relative atomic mass of Fe, Ni, Cr and other elements is small, and the shielding effect on gamma rays is limited. At the same time, B elements segregate on the grain boundaries of the matrix, and the microscopic uniformity of alloy elements needs to be optimized.
  • Fe-based shielding alloys rich in W and B elements are a new type of nuclear radiation shielding materials, in which W and B elements exist in the form of stable ternary boride FeWB phase.
  • the B element in the material has a high thermal neutron absorption cross-section and can effectively shield thermal neutrons, while the W element is a heavy element and can effectively shield gamma rays.
  • the Fe-W-B alloy powder prepared by the prior art avoids the segregation of elements to a certain extent, which is beneficial to the improvement of the comprehensive shielding performance of the alloy powder.
  • the powder needs to be further improved in terms of sphericity (only 82.7%), fluidity (19.14s/50g) and oxygen content (0.7934wt%).
  • the invention provides an Fe-based spherical shielding alloy powder with high sphericity, high fluidity and excellent comprehensive shielding performance and a preparation method thereof.
  • the Fe-based spherical shielding alloy powder provided by the present invention greatly improves the sphericity and fluidity of the Fe-based alloy powder on the premise of ensuring excellent comprehensive shielding performance, and solves the technical problems mentioned in the above-mentioned background technology.
  • the present invention provides the following technical solutions: a Fe-based spherical shielding alloy powder, the composition weight percentage of the Fe-based spherical shielding alloy powder is: W 13.6-28.9%, B 0.8-1.7%, Cr 0 ⁇ 15.0%, the balance is Fe.
  • the composition weight percent of the Fe-based spherical shielding alloy powder is: W 13.6-18.7%, B 0.8-1.4%, Cr 5-13.0%, and the balance is Fe.
  • the Fe-based spherical shielding alloy powder has high sphericity, good fluidity, uniform dispersion of the second phase in the powder, and good comprehensive shielding performance.
  • the invention provides a method for preparing Fe-based spherical shielding alloy powder, which comprises the following steps: under the condition of argon protection, the alloy raw material is smelted and atomized to obtain atomized alloy powder, and then the atomized alloy powder is heat-treated and ball milling to obtain the Fe-based spherical shielding alloy powder.
  • the preparation method specifically includes the following steps:
  • Alloy smelting batching is carried out according to the composition ratio, and the industrial pure iron, ferrochrome, and ferrotungsten raw materials are first smelted to obtain an alloy liquid, and then ferroboron is added to the alloy liquid for refining treatment;
  • Atomized powder production After the refined alloy liquid reaches the atomization temperature, pour it into the tundish, adjust the atomization pressure, carry out atomization powder production, and collect the cooled alloy powder to obtain atomized powder. alloy powder;
  • Dispersion by ball milling use a planetary ball mill to disperse the heat-treated powder by ball milling.
  • the smelting temperature in the step S1 is 1600-1700°C, and the refining treatment time is 1-4 minutes;
  • the atomic ratio of tungsten in the liquid is 1:1.
  • the atomization temperature in the step S2 is 1650-1750° C.
  • the atomization medium is argon
  • the atomization pressure is 3.5-5.5 MPa;
  • the temperature of the heat treatment in the step S3 is 900-1200° C.
  • the time of the heat treatment is 0.5-3 hours.
  • the temperature of the heat treatment in the step S3 is 1000-1100° C., and the time of the heat treatment is 1-2 hours.
  • the selection specification of the ball milling process for the heat-treated powder in the step S4 is Non-magnetic stainless steel balls are mixed according to the ball-to-material ratio of 1:1, and ball milling is carried out under the protection of an argon atmosphere.
  • the ball milling speed is 50 ⁇ 300r/min, and the ball milling time is 0.5 ⁇ 3h.
  • the powder is made by gas atomization method, the oxygen partial pressure in the atomization furnace is strictly controlled, the oxidation of W and B elements is avoided, and the comprehensive shielding performance of the powder is guaranteed.
  • the addition of Cr element can also improve the equilibrium electrode potential of the alloy powder, effectively improve the corrosion resistance of the powder, and make it suitable for more complex service environments.
  • a dispersed boride phase is obtained.
  • three boride phases with different compositions and structures, FeWB, (Fe,Cr)WB, and (Fe,Cr)W 2 B 2 , and their combinations can be obtained in the alloy.
  • the boride phase is uniformly dispersed in the powder distribution, the size can reach submicron or even nanometer size, and the alloying elements can be highly uniform. Therefore, the Fe-based spherical shielding alloy powder provided by the present invention can have excellent thermal neutron and ⁇ -ray comprehensive shielding performance.
  • the Fe-based spherical shielding alloy powder of the present invention can be applied to the filling field of nuclear radiation shielding irregular structures and the repairing field of Fe-based shielding materials.
  • Fig. 1 is the X-ray diffraction diagram of the Fe-based spherical shielding alloy powder prepared in Example 1 of the present invention
  • Fig. 2 is the surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 1 of the present invention
  • Example 3 is a cross-sectional morphology diagram of Fe-based spherical shielding alloy powder prepared in Example 1 of the present invention
  • Fig. 4 is the surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 2 of the present invention.
  • Example 5 is a cross-sectional morphology diagram of Fe-based spherical shielding alloy powder prepared in Example 2 of the present invention.
  • Fig. 6 is the X-ray diffraction diagram of the Fe-based spherical shielding alloy powder prepared in Example 3 of the present invention.
  • Fig. 7 is the surface topography diagram of the Fe-based spherical shielding alloy powder prepared in Example 3 of the present invention.
  • Fig. 8 is a cross-sectional morphology diagram of Fe-based spherical shielding alloy powder prepared in Example 3 of the present invention.
  • Fig. 9 is an X-ray diffraction pattern of Fe-based spherical shielding alloy powder prepared in Example 4 of the present invention.
  • Fig. 10 is a surface morphology diagram of Fe-based spherical shielding alloy powder prepared in Example 4 of the present invention.
  • Fig. 11 is a cross-sectional morphology diagram of Fe-based spherical shielding alloy powder prepared in Example 4 of the present invention.
  • Figure 12 is the X-ray diffraction pattern of the Fe-based spherical shielding alloy powder prepared in Example 6 of the present invention.
  • Figure 13 is a surface topography diagram of the Fe-based spherical shielding alloy powder prepared in Example 6 of the present invention.
  • Fig. 14 is the cross-sectional appearance figure of the Fe-based spherical shielding alloy powder prepared in Example 6 of the present invention.
  • Figure 15 is an X-ray diffraction pattern of Fe-based spherical shielding alloy powder prepared in Example 7 of the present invention.
  • Fig. 16 is a surface topography diagram of Fe-based spherical shielding alloy powder prepared in Example 7 of the present invention.
  • Fig. 17 is a cross-sectional morphology diagram of Fe-based spherical shielding alloy powder prepared in Example 7 of the present invention.
  • Fig. 18 is a surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Comparative Example 1 of the present invention.
  • the Fe-based alloy provided by the invention includes 13.6-28.9% W.
  • W is added to the Fe-based alloy, and the W content is controlled within the above range, which is beneficial to obtain a stable boride phase and effectively shield gamma rays, thereby improving the shielding performance of the alloy powder.
  • the Fe-based alloy provided by the invention includes 0.8-1.7% of B.
  • the invention adds B to the Fe-based alloy and controls the B content within the above range, which is beneficial to obtain a stable boride phase and effectively shield thermal neutrons, thereby improving the shielding performance of the alloy.
  • the Fe-based alloy provided by the invention includes 0-15.0% Cr.
  • the present invention adds Cr to the Fe-based spherical shielding alloy powder, and controls the content of Cr within the above range, which is beneficial to improving the sphericity, fluidity, microstructure uniformity and corrosion resistance of the alloy powder.
  • the Fe-based alloy provided by the present invention includes a balance of Fe.
  • the present invention provides a preparation method of Fe-based spherical shielding alloy powder with high sphericity, high fluidity and excellent comprehensive shielding performance described in the above technical solution, comprising the following steps:
  • the alloy raw material is melted and atomized in the atomization equipment, and the sieved atomized alloy powder is subjected to vacuum heat treatment and ball milling to obtain Fe-based alloy shielding powder.
  • the smelting temperature is 1600-1700°C; the atomization pressure of the alloy is 3.5-5.5MPa; the intermediate heat temperature of the alloy powder is 900-1200°C, and the heat treatment time is 0.5-3h.
  • the rotational speed of the ball mill is 50-300 r/min, and the milling time is 0.5-3 hours.
  • the chemical composition of the atomized alloy powder is consistent with the composition of the Fe-based spherical shielding alloy powder described in the above technical solution.
  • the preparation method of the Fe-based spherical shielding alloy powder comprises the following steps:
  • the raw materials are commercially available unless otherwise specified.
  • the pure metal of the industrial pure iron Fe the purity of the pure metal is greater than or equal to 99.9% by mass percentage.
  • the ferrotungsten, ferroboron and ferrochrome are binary master alloys corresponding to W, B and Cr. In the tungsten-iron binary alloy, by mass percentage, tungsten is 77.81%, and the balance is Fe; in the boron-iron binary alloy, by mass percentage, boron is 20.05%, and the balance is Fe. In the chromium-iron binary alloy, in terms of mass percentage, chromium is 59.12%, and the balance is Fe.
  • the raw materials corresponding to Fe, W, and Cr are preferably smelted under the protection of argon, and then the raw materials corresponding to B are added for refining treatment, which is conducive to fully mixing B with less content with other raw materials, and at the same time helps to avoid its volatile.
  • the alloy liquid After obtaining the alloy liquid, mix the alloy liquid and the raw materials of the corresponding components of B, the atomic ratio of boron (B) in the ferroboron to tungsten (W) in the alloy liquid is 1:1, and then carry out refining treatment , The refining time is 1 ⁇ 4min.
  • the refined alloy liquid is poured into a tundish for atomization and powder making to obtain atomized alloy powder, and the atomization pressure is 3.5-5.5 MPa.
  • the vacuum heat treatment temperature is 900-1200°C, preferably 1000-1100°C.
  • the vacuum heat treatment time is 0.5-3 hours, preferably 1-2 hours.
  • the cooling method of the heat treatment is furnace cooling.
  • the ball milling speed is 50-300 r/min, and the ball milling time is 0.5-3 hours.
  • the Fe-based spherical shielding alloy powder is smelted from alloy raw materials under the protection of argon, followed by atomization, heat treatment and ball mill dispersion; the melting temperature is 1600-1700°C, followed by argon
  • the precipitated phase in the microstructure of the obtained alloy powder is distributed in a network shape by gas atomization powder making. Therefore, in the present invention, when the temperature of the combined powder is raised to 900-1200° C., heat treatment is carried out by keeping the temperature for 0.5-3 hours, preferably 1-2 hours.
  • the reticular precipitates in the Fe-based spherical shielding alloy powder provided by the present invention are broken into dispersed particles, and finally transformed into stable boride phases FeWB, (Fe, Cr )WB and (Fe,Cr)W 2 B 2 to achieve the purpose of improving the powder micro-domain morphology, element uniformity and phase structure stability.
  • the powder that has been slightly bonded by heat treatment can be dispersed again, and the fluidity of the powder can be improved.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (micro positive pressure), smelt at 1650°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form an alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 3 minutes; wait for the alloy liquid After the temperature reaches 1700°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 4 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1000° C. for 1 h.
  • the atomized alloy powder and stainless steel balls were put into a planetary ball mill tank with a ball-to-material ratio of 1:1, and ball milled for 1 hour at a ball milling speed of 200 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 75.31 ⁇ m, the fluidity reaches 15.36s/50g, the sphericity reaches 92.3%, and the oxygen content is 0.0375wt%.
  • Fig. 1 is an X-ray diffraction pattern of Fe-based spherical shielding alloy powder prepared in Example 1 of the present invention.
  • the abscissa 2 ⁇ is the diffraction angle, that is, the angle between the incident X-ray and the diffraction line, and the ordinate is the diffraction intensity (dimensionless).
  • each phase has its corresponding characteristic peak, that is, the phase is different Diffraction peaks will appear at different angles.
  • Fig. 2 is a surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 1 of the present invention.
  • FIG. 3 is a cross-sectional morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 1 of the present invention.
  • Fig. 1 shows that the matrix of the Fe-based spherical shielding alloy powder provided in Example 1 of the present invention is ⁇ -(Fe,Cr), and the precipitated phase is (Fe,Cr)W 2 B 2 phase.
  • Fig. 2 shows that the Fe-based spherical shielding alloy powder provided by Example 1 of the present invention has less satellite powder and higher sphericity.
  • Figure 3 shows that the (Fe,Cr)W 2 B 2 particle phase in the Fe-based spherical shielding alloy powder provided by Example 1 of the present invention is fine and dispersedly distributed, and the microstructure is uniform, which is beneficial to obtain higher comprehensive shielding performance.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (slightly positive pressure), smelt at 1680°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 3 minutes; wait for the alloy liquid After the temperature reaches 1730°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 4 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1000° C. for 1 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 1 hour at a milling speed of 200 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder is tested, and the test contents are: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 87.37 ⁇ m, the fluidity reaches 15.74s/50g, the sphericity reaches 91.7%, and the oxygen content is 0.0318wt%.
  • Fig. 4 is a surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 2 of the present invention.
  • Fig. 5 is a cross-sectional morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 2 of the present invention.
  • Fig. 4 shows that the Fe-based spherical shielding alloy powder provided by Example 2 of the present invention has less satellite powder and higher sphericity.
  • Figure 5 shows that the (Fe,Cr)W 2 B 2 particle phase in the Fe-based spherical shielding alloy powder provided by Example 2 of the present invention is fine and dispersedly distributed, and the microstructure is uniform, which is conducive to obtaining higher comprehensive shielding performance.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (micro positive pressure), smelt at 1630°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 3 minutes; wait for the alloy liquid After the temperature reaches 1680°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 4 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1000° C. for 1 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 1 hour at a milling speed of 200 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 84.64 ⁇ m, the fluidity reaches 15.88 s/50g, the sphericity reaches 90.1%, and the oxygen content is 0.0472wt%.
  • Fig. 6 is an X-ray diffraction pattern of the Fe-based spherical shielding alloy powder prepared in Example 3 of the present invention.
  • the abscissa 2 ⁇ is the diffraction angle, that is, the angle between the incident X-ray and the diffraction line, and the ordinate is the diffraction intensity (dimensionless).
  • each phase has its corresponding characteristic peak, that is, the phase is different Diffraction peaks will appear at different angles.
  • Fig. 7 is a surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 3 of the present invention.
  • FIG. 8 is a cross-sectional morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 3 of the present invention.
  • Figure 6 shows that the matrix of the Fe-based spherical shielding alloy powder provided by Example 3 of the present invention is ⁇ -(Fe, Cr), and the precipitated phases are (Fe, Cr)W 2 B 2 and (Fe, Cr)WB structural phases, two Both are stable boride phases.
  • Fig. 7 shows that the Fe-based spherical shielding alloy powder provided by Example 3 of the present invention has less satellite powder and higher sphericity.
  • Figure 8 shows that the boride particles in the Fe-based spherical shielding alloy powder provided by Example 3 of the present invention are fine and dispersedly distributed, and the microstructure is uniform, which is beneficial to obtain higher comprehensive shielding performance.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (slightly positive pressure), smelt at 1620°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form an alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 2 minutes; wait for the alloy liquid After the temperature reaches 1670°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 4 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1000° C. for 1 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill tank with a ball-to-material ratio of 1:1, and ball milled for 0.5 h at a ball milling speed of 200 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 87.37 ⁇ m, the fluidity reaches 16.04s/50g, the sphericity reaches 89.51%, and the oxygen content is 0.0518wt%.
  • Fig. 9 is an X-ray diffraction pattern of the Fe-based spherical shielding alloy powder prepared in Example 4 of the present invention.
  • the abscissa 2 ⁇ is the diffraction angle, that is, the angle between the incident X-ray and the diffraction line, and the ordinate is the diffraction intensity (dimensionless).
  • each phase has its corresponding characteristic peak, that is, the phase is different Diffraction peaks will appear at different angles.
  • Fig. 10 is a surface morphology diagram of Fe-based spherical shielding alloy powder prepared in Example 4 of the present invention.
  • FIG. 11 is a cross-sectional morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 4 of the present invention.
  • Fig. 10 shows that the matrix of the Fe-based spherical shielding alloy powder provided in Example 4 of the present invention is ⁇ -(Fe, Cr), and the precipitated phase is a stable ternary boride phase (Fe, Cr) WB.
  • Fig. 10 shows that the Fe-based spherical shielding alloy powder provided by Example 4 of the present invention has less satellite powder and higher sphericity.
  • Figure 11 shows that the boride particles in the Fe-based spherical shielding alloy powder provided by Example 4 of the present invention are fine and dispersedly distributed, and the microstructure is uniform, which is beneficial to obtain higher comprehensive shielding performance.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (slightly positive pressure), smelt at 1615°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 2 minutes; wait for the alloy liquid After the temperature reaches 1665°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 4 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1000 °C for 1 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 1 hour at a milling speed of 200 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 88.62 ⁇ m, the fluidity reaches 16.18s/50g, the sphericity reaches 89.12%, and the oxygen content is 0.0524wt%.
  • a Fe-based spherical shielding alloy powder 77.2% Fe, 3% Cr, 18.7% W, 1.1% B.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (micro positive pressure), smelt at 1610°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 2 minutes; at 1660°C Under the condition of 5MPa argon atomization pressure, the alloy melt was atomized and powdered, and the powder was collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1050° C. for 1 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 3 hours at a milling speed of 300 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 101.36 ⁇ m, the fluidity reaches 16.29s/50g, the sphericity reaches 88.92%, and the oxygen content is 0.0530wt%.
  • Fig. 12 is an X-ray diffraction pattern of the Fe-based spherical shielding alloy powder prepared in Example 6 of the present invention.
  • the abscissa 2 ⁇ is the diffraction angle, that is, the angle between the incident X-ray and the diffraction line, and the ordinate is the diffraction intensity (dimensionless).
  • each phase has its corresponding characteristic peak, that is, the phase is different Diffraction peaks will appear at different angles.
  • Fig. 13 is a surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 6 of the present invention.
  • FIG. 14 is a cross-sectional morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 6 of the present invention.
  • Fig. 12 shows that the matrix of the Fe-based spherical shielding alloy powder provided in Example 6 of the present invention is ⁇ -(Fe, Cr), and the precipitated phase is a stable ternary boride phase (Fe, Cr) WB.
  • Fig. 13 shows that the Fe-based spherical shielding alloy powder provided by Example 6 of the present invention has less satellite powder and higher sphericity.
  • Figure 14 shows that the boride particles in the Fe-based spherical shielding alloy powder provided by Example 6 of the present invention are fine and dispersedly distributed, and the microstructure is uniform, which is beneficial to obtain higher comprehensive shielding performance.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (micro positive pressure), smelt at 1620°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 3 minutes; wait for the alloy liquid After the temperature reaches 1670°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 4 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1000° C. for 1 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 1 hour at a ball milling speed of 250 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 96.88 ⁇ m, the fluidity reaches 16.48s/50g, the sphericity reaches 87.17%, and the oxygen content is 0.0622wt%.
  • Fig. 15 is an X-ray diffraction pattern of the Fe-based spherical shielding alloy powder prepared in Example 7 of the present invention.
  • the abscissa 2 ⁇ is the diffraction angle, that is, the angle between the incident X-ray and the diffraction line, and the ordinate is the diffraction intensity (dimensionless).
  • each phase has its corresponding characteristic peak, that is, the phase is different Diffraction peaks will appear at different angles.
  • Fig. 16 is a surface morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 7 of the present invention.
  • FIG. 17 is a cross-sectional morphology diagram of the Fe-based spherical shielding alloy powder prepared in Example 7 of the present invention.
  • Fig. 15 shows that the matrix of the Fe-based spherical shielding alloy powder provided by Example 7 of the present invention is ⁇ -Fe, and the precipitated phase is a stable ternary boride phase FeWB.
  • Fig. 16 shows that the Fe-based spherical shielding alloy powder provided by Example 7 of the present invention has less satellite powder and higher sphericity.
  • Figure 17 shows that the boride particles in the Fe-based spherical shielding alloy powder provided by Example 7 of the present invention are fine and dispersedly distributed, and the microstructure is uniform, which is beneficial to obtain higher comprehensive shielding performance.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (slightly positive pressure), smelt at 1620°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form an alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 2 minutes; wait for the alloy liquid After the temperature reaches 1670°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 3.5 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 900° C. for 0.5 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 1 hour at a milling speed of 200 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 94.65 ⁇ m, the fluidity reaches 16.27s/50g, the sphericity reaches 90.35%, and the oxygen content is 0.0632wt%.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of the ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (micro positive pressure), smelt at 1675°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 3 minutes; wait for the alloy liquid After the temperature reaches 1725°C, it is poured into the tundish, and the alloy melt is atomized and powdered with an argon atomization pressure of 5 MPa, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1100° C. for 2 hours.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 2 hours at a ball milling speed of 200 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 99.43 ⁇ m, the fluidity reaches 15.94s/50g, the sphericity reaches 88.56%, and the oxygen content is 0.0467wt%.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (micro positive pressure), smelt at 1700°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 4 minutes; at 1750°C Under these conditions, an argon atomization pressure of 5.5 MPa is used to atomize the alloy melt to make powder, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1200° C. for 3 hours.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 3 hours at a milling speed of 300 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based spherical shielding alloy powder.
  • the performance of the Fe-based spherical shielding alloy powder was tested, and the test contents were: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 103.32 ⁇ m, the fluidity reaches 16.13s/50g, the sphericity reaches 87.6%, and the oxygen content is 0.0539wt%.
  • An Fe-based shielding alloy powder 80.2% Fe, 18.7% W, 1.1B.
  • the preparation method of the alloy is as follows: add industrial pure iron, ferrotungsten, and ferrochrome into the magnesia crucible according to the ratio of ingredients, add ferroboron into the secondary feeding hopper, charge the material tightly, vacuumize until the vacuum degree is 4Pa, and fill Enter argon gas to 0.1MPa (micro positive pressure), smelt at 1700°C until industrial pure iron, ferrotungsten, and ferrochrome are completely melted to form alloy liquid, add ferroboron in the secondary feeding hopper, and refine for 4 minutes; at 1750°C Under the condition of water pressure of 5MPa, the alloy melt is atomized and pulverized, and the powder is collected.
  • the collected powder was heat-treated in a vacuum tube furnace at 1050° C. for 1 h.
  • the atomized powder and stainless steel balls were put into a planetary ball mill jar with a ball-to-material ratio of 1:1, and ball milled for 3 hours at a milling speed of 300 r/min.
  • the ball-milled alloy powder is taken out and vacuum-packed to obtain Fe-based shielding alloy powder.
  • the performance of the Fe-based shielding alloy powder is tested, and the test contents are: laser particle size, fluidity, sphericity, and oxygen content.
  • the test results are: the D 50 of the alloy powder is 110.53 ⁇ m, the fluidity reaches 19.14s/50g, the sphericity reaches 78.47%, and the oxygen content is 0.7934wt%.
  • FIG. 18 is a surface morphology diagram of the Fe-based alloy powder prepared in Comparative Example 1 of the present invention.
  • Fig. 18 shows that the Fe-based alloy powder provided by Comparative Example 1 of the present invention has a low overall powder sphericity, and there are a large amount of special-shaped powder and satellite powder, so the powder has a low sphericity.
  • the present invention makes powder by gas atomization method, strictly controls the oxygen partial pressure in the atomization furnace, avoids the oxidation of W and B elements, and ensures the comprehensive shielding performance of the powder.
  • the addition of Cr element can also improve the equilibrium electrode potential of the alloy powder, effectively improve the corrosion resistance of the powder, and make it suitable for more complex service environments.
  • powder microstructure advantages the present invention obtains dispersed boride phases through atomization and subsequent heat treatment.
  • Cr element By adjusting the Cr element, three boride phases with different compositions and structures, FeWB, (Fe,Cr)WB, and (Fe,Cr)W 2 B 2 , and their combinations can be obtained in the alloy.
  • the boride phase is uniformly dispersed in the powder distribution, the size can reach submicron or even nanometer size, and the alloying elements can be highly uniform. Therefore, the Fe-based spherical shielding alloy powder can have excellent thermal neutron and ⁇ -ray comprehensive shielding performance.
  • the Fe-based spherical shielding alloy powder of the present invention can be applied to the filling field of nuclear radiation shielding irregular structures and the repairing field of Fe-based shielding materials.

Abstract

一种Fe基球形屏蔽合金粉末及其制备方法，Fe基球形屏蔽合金粉末的组分重量百分含量为：W 13.6～28.9％，B 0.8～1.7％，Cr 0～15.0％，余量为Fe。Fe基球形屏蔽合金粉末制备方法具体步骤为：按照Fe基球形屏蔽合金粉末的组分及组分配比称取原料，并在氩气保护下进行熔炼、雾化得到合金粉末，再对合金粉末进行热处理和球磨分散，最终得到Fe基球形屏蔽合金粉末。

Description

一种Fe基球形屏蔽合金粉末及其制备方法
本申请要求于2021年08月27日提交中国专利局、申请号为CN202110995961.0、发明名称为“一种Fe基球形屏蔽合金粉末及其制备方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及核辐射屏蔽材料领域，具体涉及一种Fe基球形屏蔽合金粉末及其制备方法。
背景技术
核能是一种结构稳定、密度能量高的清洁型能源，是人类能源供给的有益补充。在核能源系统中，反应堆是核心部分。核反应堆中，核裂变(或聚变)会产生各种辐射射线，如不同能级的中子、γ射线、二次γ射线及其它带电粒子和高能射线，这些射线能够直接伤害人体，也可通过污染空气、土壌、水源及食物等，间接对人体造成损害。一定剂量的射线进入人体后，对人体的组织产生电离作用，致使细胞变形、组织损伤，引起人体器官功能紊乱、新陈代谢障碍等疾病。同时还会使结构材料及机器设备发热、活化，降低其寿命。因此，必须对核反应堆产生的辐射进行有效屏蔽。
目前的核反应堆中的大型屏蔽结构件难以一体化成型，广泛采用的焊接加工手段，不可避免的会产生大量的异形区域，成为辐射屏蔽的薄弱区，对人员和设备安全均构成威胁。目前，主要采用流动性好、球形度高、综合屏蔽性能优异的粉末对异构区域进行致密填充，弥补主体屏蔽性能的不足，完善屏蔽体的屏蔽性能。除此之外，一些大型Fe基屏蔽体材料在使用过程中，会出现局部磨损或腐蚀，造成屏蔽体屏蔽性能的下降，故也需具有优异屏蔽性能的Fe基合金粉末对屏蔽体的缺陷进行填充和修补，从而大幅降低屏蔽系统的维护和修理成本。
目前，在上述领域中应用最为广泛的是气雾化方法制备的含硼不锈钢粉末，其具有球形度高，流动性好，热中子屏蔽性能好以及耐腐蚀等优点。但其也存在一些不足：在含硼不锈钢粉末中，Fe、Ni、Cr等元素的相对原子质量较小，对γ射线的屏蔽效果有限。同时，B元素在基体晶界上存在偏析，合金元素的微观均匀性有待优化。富含W、B元素的Fe基屏蔽合金作为一类新型核辐射屏蔽用材料，其中W、B元素以稳定的三元硼化物FeWB相的形式存在。材料中的B元素具有高的热中子吸收截面，能有效屏蔽热中子，而W元素属于重元素，能有效屏蔽γ射线。目前，现有技术制备的Fe-W-B合金粉末，一定程度上避免了元素的偏析，有利于合金粉末综合屏蔽性能的提高。但该粉末在球形度(仅有82.7％)、流动性(19.14s/50g)以及氧含量(0.7934wt％)方面还需进一步提高。
发明内容
为解决现有技术中存在的问题，本发明提供了一种具有高球形度、高流动性及优异综合屏蔽性能的Fe基球形屏蔽合金粉末及其制备方法。本发明提供的Fe基球形屏蔽合金粉末在保证具有优异综合屏蔽性能的前提下，大幅度提高Fe基合金粉末的球形度和流动性，解决了上述背景技术中提到的技术问题。
为实现上述目的，本发明提供如下技术方案：一种Fe基球形屏蔽合金粉末，所述Fe基球形屏蔽合金粉末的组分重量百分含量为：W 13.6～28.9％，B 0.8～1.7％，Cr 0～15.0％，余量为Fe。
优选的，所述Fe基球形屏蔽合金粉末的组分重量百分含量为：W 13.6～18.7％，B 0.8～1.4％，Cr 5～13.0％，余量为Fe。
所述Fe基球形屏蔽合金粉末球形度高，流动性良好，粉末中的第二相弥散均匀，综合屏蔽性能好。
本发明提供了一种Fe基球形屏蔽合金粉末的制备方法，包括以下步骤：在氩气保护条件下，将合金原料经熔炼、雾化后得到雾化合金粉末，再对雾化合金粉末进行热处理和球磨分散，得到所述Fe基球形屏蔽合金粉末。
优选的，所述制备方法具体包括以下步骤：
S1、合金熔炼：按成分配比进行配料，先将工业纯铁、铬铁、钨铁原料进行熔炼，得到合金液，再将硼铁加入所述合金液中，进行精炼处理；
S2、雾化制粉：待精炼完成的合金液达到雾化温度后，将其倒入中间包内，调节雾化压力，进行雾化制粉，将冷却后的合金粉末进行收集，得到雾化合金粉末；
S3、热处理：采用真空管式炉对所述雾化合金粉末进行热处理；
S4、球磨分散：采用行星球磨机对热处理后的粉末进行球磨分散。
优选的，所述步骤S1中的熔炼温度为1600～1700℃，精炼处理的时间为1～4min；在所述将硼铁加入合金液的步骤中，所述硼铁中的硼与所述合金液中的钨的原子比为1:1。
优选的，所述步骤S2中的雾化温度为1650～1750℃，雾化介质采用氩气，雾化压力为3.5～5.5MPa；
优选的，所述步骤S3中的热处理的温度为900～1200℃，热处理的时间为0.5～3h。
优选的，所述步骤S3中的热处理的温度为1000～1100℃，热处理的时间为1～2h。
优选的，所述步骤S4中的热处理后粉末的球磨工艺选择规格为
Figure PCTCN2022115085-appb-000001
Figure PCTCN2022115085-appb-000002
无磁不锈钢球，按1:1球料比混合，在氩气气氛保护下进行球磨，球磨转速为50～300r/min，球磨时间为0.5～3h。
本发明的有益效果是：
a.粉末成分优势：通过气雾化法制粉，严格控制雾化炉内的氧分压， 避免W，B元素的氧化，保证了粉末的综合屏蔽性能。Cr元素的添加还可以提高合金粉末的平衡电极电位，有效提高粉末的耐蚀性能，使其可以适用于更多复杂的服役环境。
b.粉末表面形貌优势：由于Cr元素的添加，可降低雾化时金属熔体的熔点、导热系数及比热容等参数，减缓了熔体的凝固速率，延长其凝固时间。因此，合金熔滴可在其完全凝固前充分球化，形成高球形度的金属粉末。通过球磨对热处理过程中粘结的粉末进行分散，所得合金粉末的平均球形度可达87％以上，流动性优于17.0s/50g。
c.粉末微观结构优势：通过雾化和后续热处理，获得了弥散分布的硼化物相。通对Cr元素的调控，可在合金中获得FeWB、(Fe,Cr)WB、(Fe,Cr)W 2B 2这三种不同成分和结构的硼化相及其组合。硼化物相在粉末分布均匀弥散，尺寸可达亚微米甚至纳米尺寸，合金元素可达到高度均匀。因此，本发明提供发的所述Fe基球形屏蔽合金粉末可具备优异的热中子和γ射线综合屏蔽性能。
d.应用优势：本发明的Fe基球形屏蔽合金粉末由于其优异的流动性、球形度和综合屏蔽性能，可应用于核辐射屏蔽异形结构的填充领域和Fe基屏蔽体材料的修补领域。
说明书附图
图1为本发明实施例1制得的Fe基球形屏蔽合金粉末的X射线衍射图；
图2为本发明实施例1制得的Fe基球形屏蔽合金粉末表面形貌图；
图3为本发明实施例1制得的Fe基球形屏蔽合金粉末的截面形貌图；
图4为本发明实施例2制得的Fe基球形屏蔽合金粉末表面形貌图；
图5为本发明实施例2制得的Fe基球形屏蔽合金粉末的截面形貌图；
图6为本发明实施例3制得的Fe基球形屏蔽合金粉末的X射线衍射图；
图7为本发明实施例3制得的Fe基球形屏蔽合金粉末的表面形貌图；
图8为本发明实施例3制得的Fe基球形屏蔽合金粉末的截面形貌图；
图9为本发明实施例4制得的Fe基球形屏蔽合金粉末的X射线衍射图；
图10为本发明实施例4制得的Fe基球形屏蔽合金粉末表面形貌图；
图11为本发明实施例4制得的Fe基球形屏蔽合金粉末的截面形貌图；
图12为本发明实施例6制得的Fe基球形屏蔽合金粉末的X射线衍射图；
图13为本发明实施例6制得的Fe基球形屏蔽合金粉末的表面形貌图；
图14为本发明实施例6制得的Fe基球形屏蔽合金粉末的截面形貌 图；
图15为本发明实施例7制得的Fe基球形屏蔽合金粉末的X射线衍射图；
图16为本发明实施例7制得的Fe基球形屏蔽合金粉末的表面形貌图；
图17为本发明实施例7制得的Fe基球形屏蔽合金粉末的截面形貌图；
图18为本发明对比例1制得的Fe基球形屏蔽合金粉末的表面形貌图。
具体实施方式
请参阅图1-图17，一种具有高球形度、高流动性及优异综合屏蔽性能的新型Fe基球形屏蔽合金粉末，所述Fe基球形屏蔽合金粉末的组分重量百分含量为：W 13.6～28.9％，B 0.8～1.7％，Cr 0～15.0％，余量为Fe。
以重量百分含量计，本发明提供的Fe基合金包括13.6～28.9％的W。本发明在Fe基合金中添加W，并将W的含量控制在上述范围内，有利于获得稳定的硼化物相，并且有效屏蔽γ射线，从而提高合金粉末的屏蔽性能。
以重量百分含量计，本发明提供的Fe基合金包括0.8～1.7％的B。本发明在Fe基合金中添加B，并将B的含量控制在上述范围内，有利于获得稳定的硼化物相，并且有效屏蔽热中子，从而提高合金屏蔽性能。
以重量百分含量计，本发明提供的Fe基合金包括0～15.0％的Cr。本发明在Fe基球形屏蔽合金粉末中添加Cr，并将Cr的含量控制在上述范围内，有利于提高合金粉末的球形度、流动性、微观组织的均匀性和耐蚀性能。
本发明提供的Fe基合金包括余量的Fe。
本发明提供了上述技术方案所述具有高球形度、高流动性及优异综合屏蔽性能的Fe基球形屏蔽合金粉末的制备方法，包括以下步骤：
在氩气保护条件下，将合金原料在雾化设备内进行熔炼与雾化过程，对筛分后的雾化合金粉末进行真空热处理、球磨，得到Fe基合金屏蔽粉末。
在本发明中，所述熔炼温度为1600～1700℃；所述合金的雾化压力为3.5～5.5MPa；所述合金粉末的中热处温度为900～1200℃，热处理时间为0.5～3h。所述球磨转速为50～300r/min，球磨时间为0.5～3h。所述雾化合金粉末的化学成分与上述技术方案所述Fe基球形屏蔽合金粉末的组分组成一致。
在本发明中，当所述合金原料包括W、B、Cr和Fe时，所述Fe基球形屏蔽合金粉末的制备方法包括以下步骤：
(1)按成分配比进行配料，先将工业纯铁、铬铁、钨铁原料进行熔炼， 得到合金液，再将硼铁加入所述合金液中，进行精炼处理；
(2)待精炼完成的合金液达到雾化温度后，将其倒入中间包内，调节雾化压力，进行雾化制粉；将冷却后的雾化合金粉末进行收集，得到雾化合金粉末；
(3)采用真空管式炉对所述雾化合金粉末进行热处理；
(4)采用行星球磨机对热处理后的粉末进行球磨分散。
在本发明中，所述原料如无特别说明，均为市售商品。在本发明的实施例中，所述工业纯铁Fe的纯金属，所述纯金属的纯度以质量百分数计≥99.9％。所述钨铁、硼铁、铬铁为对应W、B、Cr的二元中间合金。所述钨铁二元合金中，以质量百分比计，钨为77.81％，余量为Fe；所述硼铁二元合金中，以质量百分比计，硼为20.05％，余量为Fe。所述铬铁二元合金中，以质量百分比计，铬为59.12％，余量为Fe。
本发明优选将对应Fe、W、Cr的原料在氩气保护下熔炼后，然后再加入对应B的原料进行精炼处理，有利于使含量较少的B能够与其它原料充分混合，同时有利于避免其挥发。
得到合金液后，将合金液和B对应组分的原料混合，所述硼铁中的硼(B)与所述合金液中的钨(W)的原子比为1:1，然后进行精炼处理，精炼时间为1～4min。
在本发明中，待熔体达到1670～1730℃后，将精炼后的合金液倒入中间包，进行雾化制粉，得到雾化合金粉末，所述雾化压力为3.5～5.5MPa。
在本发明中，所述真空热处理温度为900～1200℃，优选为1000～1100℃。
本发明中，所述真空热处理时间为0.5～3h，优选为1～2h。
在本发明中，所述热处理的冷却方式均为随炉冷却。
本发明中球磨转速为50～300r/min，球磨时间为0.5～3h。
在本发明中，所述Fe基球形屏蔽合金粉末由合金原料在氩气保护条件下熔炼，随后经雾化、热处理和球磨分散得到；所述熔炼的温度为1600～1700℃，随后进行氩气气雾化制粉，所得合金粉末微观组织中的析出相呈网状分布。因此，本发明将合粉末升温到900～1200℃时，保温0.5～3h进行热处理，优选为1～2h。通过促进W、B元素的扩散，使本发明提供的Fe基球形屏蔽合金粉末中网状的析出相被破碎成弥撒分布的颗粒状，并最终转化为稳定的硼化物相FeWB、(Fe,Cr)WB及(Fe,Cr)W 2B 2，达到提高粉末微区形貌、元素均匀性和相结构稳定性的目的。最后通过球磨分散处理，使得热处理而发生轻微粘接的粉末再次分散，提高粉末的流动性。
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本发明一部分实施例， 而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
实施例1
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：67.2％Fe，13％Cr，18.7％W，1.1％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1650℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼3min；待合金液温度达到1700℃后，将其倒入中间包内，采用4MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1000℃条件下，保温1h进行热处理。后续，以1:1的球料比，将雾化合金粉末和不锈钢小球放入行星球磨罐中，在球磨转速为200r/min条件下，球磨1h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为75.31μm，流动性达到15.36s/50g，球形度达92.3％，氧含量为0.0375wt％。
图1为本发明实施例1制得的Fe基球形屏蔽合金粉末的X射线衍射图。横坐标2θ为衍射角，即入射X射线与衍射线的夹角，纵坐标为衍射强度(无量纲)，X射线衍射图中，每个物相都有其对应的特征峰，即物相不同会在不同角度出现衍射峰。图2为本发明实施例1制得的Fe基球形屏蔽合金粉末表面形貌图。图3为本发明实施例1制得的Fe基球形屏蔽合金粉末的截面形貌图。图1说明本发明实施例1提供的Fe基球形屏蔽合金粉末的基体为α-(Fe,Cr)，析出相为(Fe,Cr)W 2B 2相。图2说明本发明实施例1提供的Fe基球形屏蔽合金粉末卫星粉较少，球形度较高。图3说明本发明实施例1提供的Fe基球形屏蔽合金粉末中的(Fe,Cr)W 2B 2颗粒相细小且呈弥散分布，微观组织均匀，有利于获得较高的综合屏蔽性能。
实施例2
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：65.2％Fe，15％Cr，18.7％W，1.1％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1680℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼3min；待合金液温度达到1730℃后，将其倒入中间包内，采用4MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1000℃ 条件下，保温1h进行热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为200r/min条件下，球磨1h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为87.37μm，流动性达到15.74s/50g，球形度达91.7％，氧含量为0.0318wt％。
图4为本发明实施例2制得的Fe基球形屏蔽合金粉末表面形貌图。图5为本发明实施例2制得的Fe基球形屏蔽合金粉末的截面形貌图。图4说明本发明实施例2提供的Fe基球形屏蔽合金粉末卫星粉较少，球形度较高。图5说明本发明实施例2提供的Fe基球形屏蔽合金粉末中的(Fe,Cr)W 2B 2颗粒相细小且呈弥散分布，微观组织均匀，有利于获得较高的综合屏蔽性能。
实施例3
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：69.2％Fe，10％Cr，18.7％W，1.1％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1630℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼3min；待合金液温度达到1680℃后，将其倒入中间包内，采用4MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1000℃条件下，保温1h进行热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为200r/min条件下，球磨1h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为84.64μm，流动性达到15.88s/50g，球形度达90.1％，氧含量为0.0472wt％。
图6为本发明实施例3制得的Fe基球形屏蔽合金粉末的X射线衍射图。横坐标2θ为衍射角，即入射X射线与衍射线的夹角，纵坐标为衍射强度(无量纲)，X射线衍射图中，每个物相都有其对应的特征峰，即物相不同会在不同角度出现衍射峰。图7为本发明实施例3制得的Fe基球形屏蔽合金粉末表面形貌图。图8为本发明实施例3制得的Fe基球形屏蔽合金粉末的截面形貌图。图6说明本发明实施例3提供的Fe基球形屏蔽合金粉末的基体为α-(Fe,Cr)，析出相为(Fe,Cr)W 2B 2和(Fe,Cr)WB结构相，二者均为稳定的硼化物相。图7说明本发明实施例3提供的Fe基球形屏蔽合金粉末卫星粉较少，球形度较高。图8说明本发明实施例3提供的 Fe基球形屏蔽合金粉末中硼化物颗粒相细小且呈弥散分布，微观组织均匀，有利于获得较高的综合屏蔽性能。
实施例4
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：72.2％Fe，8％Cr，18.7％W，1.1％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1620℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼2min；待合金液温度达到1670℃后，将其倒入中间包内，采用4MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1000℃条件下，保温1h进行热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为200r/min条件下，球磨0.5h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为87.37μm，流动性达到16.04s/50g，球形度达89.51％，氧含量为0.0518wt％。
图9为本发明实施例4制得的Fe基球形屏蔽合金粉末的X射线衍射图。横坐标2θ为衍射角，即入射X射线与衍射线的夹角，纵坐标为衍射强度(无量纲)，X射线衍射图中，每个物相都有其对应的特征峰，即物相不同会在不同角度出现衍射峰。图10为本发明实施例4制得的Fe基球形屏蔽合金粉末表面形貌图。图11为本发明实施例4制得的Fe基球形屏蔽合金粉末的截面形貌图。图10说明本发明实施例4提供的Fe基球形屏蔽合金粉末的基体为α-(Fe,Cr)，析出相为稳定的三元硼化物相(Fe,Cr)WB。图10说明本发明实施例4提供的Fe基球形屏蔽合金粉末卫星粉较少，球形度较高。图11说明本发明实施例4提供的Fe基球形屏蔽合金粉末中的硼化物颗粒相细小且呈弥散分布，微观组织均匀，有利于获得较高的综合屏蔽性能。
实施例5
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：75.2％Fe，5％Cr，18.7％W，1.1％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1615℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼2min；待合金液温度达到1665℃后，将其倒入中间包内，采用4MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1000℃条件 下，保温1h进行热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为200r/min条件下，球磨1h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为88.62μm，流动性达到16.18s/50g，球形度达89.12％，氧含量为0.0524wt％。
实施例6
一种Fe基球形屏蔽合金粉末：77.2％Fe，3％Cr，18.7％W，1.1％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1610℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼2min；在1660℃下，采用5MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1050℃条件下，保温1h热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为300r/min条件下，球磨3h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为101.36μm，流动性达到16.29s/50g，球形度达88.92％，氧含量为0.0530wt％。
图12为本发明实施例6制得的Fe基球形屏蔽合金粉末的X射线衍射图。横坐标2θ为衍射角，即入射X射线与衍射线的夹角，纵坐标为衍射强度(无量纲)，X射线衍射图中，每个物相都有其对应的特征峰，即物相不同会在不同角度出现衍射峰。图13为本发明实施例6制得的Fe基球形屏蔽合金粉末表面形貌图。图14为本发明实施例6制得的Fe基球形屏蔽合金粉末的截面形貌图。图12说明本发明实施例6提供的Fe基球形屏蔽合金粉末的基体为α-(Fe,Cr)，析出相为稳定的三元硼化物相(Fe,Cr)WB。图13说明本发明实施例6提供的Fe基球形屏蔽合金粉末卫星粉较少，球形度较高。图14说明本发明实施例6提供的Fe基球形屏蔽合金粉末中的硼化物颗粒相细小且呈弥散分布，微观组织均匀，有利于获得较高的综合屏蔽性能。
实施例7
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：80.2％Fe，18.7％W，1.1％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1620℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼3min；待合金液温度达到1670℃后，将其倒入中间包 内，采用4MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1000℃条件下，保温1h进行热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为250r/min条件下，球磨1h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为96.88μm，流动性达到16.48s/50g，球形度达87.17％，氧含量为0.0622wt％。
图15为本发明实施例7制得的Fe基球形屏蔽合金粉末的X射线衍射图。横坐标2θ为衍射角，即入射X射线与衍射线的夹角，纵坐标为衍射强度(无量纲)，X射线衍射图中，每个物相都有其对应的特征峰，即物相不同会在不同角度出现衍射峰。图16为本发明实施例7制得的Fe基球形屏蔽合金粉末表面形貌图。图17为本发明实施例7制得的Fe基球形屏蔽合金粉末的截面形貌图。图15说明本发明实施例7提供的Fe基球形屏蔽合金粉末的基体为α-Fe，析出相为稳定的三元硼化物相FeWB。图16说明本发明实施例7提供的Fe基球形屏蔽合金粉末卫星粉较少，球形度较高。图17说明本发明实施例7提供的Fe基球形屏蔽合金粉末中的硼化物颗粒相细小且呈弥散分布，微观组织均匀，有利于获得较高的综合屏蔽性能。
实施例8
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：72.6％Fe，13％Cr，13.6％W，0.8％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1620℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼2min；待合金液温度达到1670℃后，将其倒入中间包内，采用3.5MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在900℃条件下，保温0.5h进行热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为200r/min条件下，球磨1h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为94.65μm，流动性达到16.27s/50g，球形度达90.35％，氧含量为0.0632wt％。
实施例9
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：61.8％Fe，13％Cr，23.8％W，1.4％B。该合金的制备方法为：将原 料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1675℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼3min；待合金液温度达到1725℃后，将其倒入中间包内，采用5MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1100℃条件下，保温2h进行热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为200r/min条件下，球磨2h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为99.43μm，流动性达到15.94s/50g，球形度达88.56％，氧含量为0.0467wt％。
实施例10
一种高球形度、高流动性及综合屏蔽性能好的Fe基球形屏蔽合金粉末：56.4％Fe，13％Cr，28.9％W，1.7％B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1700℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼4min；在1750℃条件下，采用5.5MPa的氩气雾化压力对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1200℃条件下，保温3h热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为300r/min条件下，球磨3h。最后，取出球磨后的合金粉末，并采用真空封装，得到Fe基球形屏蔽合金粉末。
对Fe基球形屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为103.32μm，流动性达到16.13s/50g，球形度达87.6％，氧含量为0.0539wt％。
对比例1
一种Fe基屏蔽合金粉末：80.2％Fe，18.7％W，1.1B。该合金的制备方法为：将原料工业纯铁、钨铁、铬铁按成分配比加入镁砂坩埚中，硼铁加入二次加料斗中，加料紧实，抽真空至真空度为4Pa，充入氩气至0.1MPa(微正压)，在1700℃条件下熔炼至工业纯铁、钨铁、铬铁完全熔化形成合金液，加入二次加料斗中的硼铁，精炼4min；在1750℃条件下，采用5MPa的水压条件下对合金熔体进行雾化制粉，并对粉末进行收集。随后，将收集得到的粉末采用真空管式炉中在1050℃下，保温1h热处理。后续，以1:1的球料比，将雾化粉末和不锈钢小球放入行星球磨罐中，在球磨转速为300r/min条件下，球磨3h。最后，取出球磨后的合金粉末， 并采用真空封装，得到Fe基屏蔽合金粉末。
对Fe基屏蔽合金粉末的性能进行测试，测试内容为：激光粒度、流动性、球形度、氧含量。测试结果为：合金粉末的D 50为110.53μm，流动性达到19.14s/50g，球形度达78.47％，氧含量为0.7934wt％。
图18为本发明对比例1制得的Fe基合金粉末表面形貌图。图18说明本发明对比例1提供的Fe基合金粉末，粉末总体球形度较低，存在大量的异形粉和卫星粉，故粉末的球形度较低。
通过本发明制得的Fe基球形屏蔽合金粉末具备有以下优势：
a.粉末成分优势：本发明通过气雾化法制粉，严格控制雾化炉内的氧分压，避免W，B元素的氧化，保证了粉末的综合屏蔽性能。Cr元素的添加还可以提高合金粉末的平衡电极电位，有效提高粉末的耐蚀性能，使其可以适用于更多复杂的服役环境。
b.粉末表面形貌优势：由于Cr元素的添加，可降低雾化时金属熔体的熔点、导热系数及比热容等参数，减缓了熔体的凝固速率，延长其凝固时间。因此，合金熔滴可在其完全凝固前充分球化，形成高球形度的金属粉末。本发明通过球磨对热处理过程中粘结的粉末进行分散，所得Fe基球形屏蔽合金粉末的平均球形度为87％以上，流动性优于17.0s/50g。
c.粉末微观结构优势：粉末微观结构优势：本发明通过雾化和后续热处理，获得了弥散分布的硼化物相。通对Cr元素的调控，可在合金中获得FeWB、(Fe,Cr)WB、(Fe,Cr)W 2B 2这三种不同成分和结构的硼化相及其组合。硼化物相在粉末分布均匀弥散，尺寸可达亚微米甚至纳米尺寸，合金元素可达到高度均匀。因此，Fe基球形屏蔽合金粉末可具备优异的热中子和γ射线综合屏蔽性能。
d.应用优势：本发明的Fe基球形屏蔽合金粉末由于其优异的流动性、球形度和综合屏蔽性能，可应用于核辐射屏蔽异形结构的填充领域和Fe基屏蔽体材料的修补领域。
尽管参照前述实施例对本发明进行了详细的说明，对于本领域的技术人员来说，其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换，凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围。

Claims (13)

  1. 一种Fe基球形屏蔽合金粉末，其特征在于，所述Fe基球形屏蔽合金粉末的组分重量百分含量为：W 13.6～28.9％，B 0.8～1.7％，Cr 0～15.0％，余量为Fe。
  2. 根据权利要求1所述的Fe基球形屏蔽合金粉末，其特征在于，所述Fe基球形屏蔽合金粉末的平均球形度为87％以上，流动性优于17.0s/50g；所述Fe基球形屏蔽合金粉末中具有FeWB、(Fe,Cr)WB、(Fe,Cr)W 2B 2三种不同成分和结构的硼化相及其组合。
  3. 根据权利要求1所述的Fe基球形屏蔽合金粉末，其特征在于，所述Fe基球形屏蔽合金粉末的组分重量百分含量为：W 13.6～18.7％，B 0.8～1.4％，Cr 5～13.0％，余量为Fe。
  4. 根据权利要求1～3任一项所述的一种Fe基球形屏蔽合金粉末的制备方法，其特征在于，包括以下步骤：在氩气保护条件下，将合金原料经熔炼、雾化后得到雾化合金粉末，再对所述雾化合金粉末进行热处理和球磨分散，得到所述Fe基球形屏蔽合金粉末。
  5. 根据权利要求4所述的制备方法，其特征在于，当所述合金原料包括W、B、Cr和Fe时，所述制备方法具体步骤为：
    S1、合金熔炼：按成分配比进行配料，先将工业纯铁、铬铁、钨铁原料进行熔炼，得到合金液，再将硼铁加入所述合金液中，进行精炼处理；
    S2、雾化制粉：待精炼完成的合金液达到雾化温度后，将其倒入中间包内，调节雾化压力，进行雾化制粉，将冷却后的合金粉末进行收集，得到雾化合金粉末；
    S3、热处理：采用真空管式炉对所述雾化合金粉末进行热处理；
    S4、球磨分散：采用行星球磨机对热处理后的粉末进行球磨分散，得到所述Fe基球形屏蔽合金粉末。
  6. 根据权利要求5所述的制备方法，其特征在于：步骤S1中的熔炼温度为1600～1700℃，精炼时间为1～4min；在所述将硼铁加入合金液的步骤中，所述硼铁中的硼与所述合金液中的钨的原子比为1:1。
  7. 根据权利要求4或5所述的制备方法，其特征在于：所述雾化的温度为1650～1750℃，雾化介质采用氩气，雾化压力为3.5～5.5MPa。
  8. 根据权利要求4或5所述的制备方法，其特征在于：所述热处理的温度为900～1200℃，热处理时间为0.5～3h。
  9. 根据权利要求8所述的制备方法，其特征在于，所述热处理的温度为1000～1100℃，热处理时间为1～2h。
  10. 根据权利要求5所述的制备方法，其特征在于，步骤S4中的球磨工艺选择规格为
    Figure PCTCN2022115085-appb-100001
    无磁不锈钢球，按1:1球料比混合，在氩气气氛保护下进行球磨，球磨转速为50～300r/min，球磨时间为0.5～3h。
  11. 根据权利要求5所述的制备方法，其特征在于，所述工业纯铁铁的纯度以质量百分数计≥99.9％；所述钨铁二院合金中，以质量百分含量计，钨为77.81％，余量为Fe；所述硼铁二元合金中，以质量百分含量计，硼为20.05％，余量为Fe；所述铬铁二元合金中，以质量百分含量计，铬为59.12％，余量为Fe。
  12. 根据权利要求5所述的制备方法，其特征在于，所述精炼的时间为1～4min。
  13. 根据权利要求5或8所述的制备方法，其特征在于，所述热处理为真空热处理。
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