CN117066509A - Preparation method of metal/ceramic microsphere composite neutron absorption material - Google Patents

Preparation method of metal/ceramic microsphere composite neutron absorption material Download PDF

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CN117066509A
CN117066509A CN202211524206.5A CN202211524206A CN117066509A CN 117066509 A CN117066509 A CN 117066509A CN 202211524206 A CN202211524206 A CN 202211524206A CN 117066509 A CN117066509 A CN 117066509A
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metal
ceramic
sintering
ceramic microspheres
microspheres
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范武刚
张兆泉
王晓姣
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Shanghai Institute of Ceramics of CAS
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Shanghai Institute of Ceramics of CAS
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Abstract

The invention relates to a preparation method of a metal/ceramic microsphere composite neutron absorption material, which comprises the following steps: the metal/ceramic microsphere composite neutron absorbing material is prepared by taking metal powder and ceramic microspheres as raw materials, uniformly mixing, and then carrying out hot-pressing sintering; the temperature of the hot-press sintering is below the melting point of the metal, and the pressure of the hot-press sintering is 10-30 MPa; the preparation method of the metal/ceramic microsphere composite neutron absorbing material is characterized in that the metal/ceramic microsphere composite neutron absorbing material comprises a continuous phase formed by a metal matrix and ceramic microspheres which are dispersed in the metal matrix and serve as a disperse phase; the ceramic microsphere mainly comprises rare earth oxide.

Description

Preparation method of metal/ceramic microsphere composite neutron absorption material
Technical Field
The invention relates to a preparation method of a metal/ceramic microsphere composite neutron absorption material (comprising a structure and a composition), which can be applied to manufacturing a nuclear reactor control rod and a neutron shielding material, and belongs to the field of materials.
Background
Neutron absorbing materials loaded in the control rod bundle cladding of a nuclear reactor are largely divided into two types, metal and ceramic (powder). Metals such as hafnium (Hf), tungsten (W), silver indium cadmium (Ag-In-Cd, AIC) and stainless steel rods. The control of reactor power is realized by utilizing different neutron absorption sections of Hf, cd, W and Fe elements. Although AIC has better absorption effect on neutrons in a wider energy range, and is simpler and more convenient to process as metal, the low melting point can cause the risks of fusion and failure under accident conditions such as cold loss. Meanwhile, the safety margin is insufficient for a high-power pressurized water reactor. The high density of metal Hf can burden the operation of the control rod driving mechanism and is costly, and is currently used in many small stacks. One of the advantages of metallic neutron absorbing materials is high thermal conductivity, low internal temperature of the core block under high temperature irradiation, but high chemical activity,High temperature creep, etc. The neutron absorbing material of ceramics comprises natural and B10 enriched boron carbide (B 4 C) Boric acid, dysprosium titanate (Dy) 2 TiO 5 ) Rare earth hafnates (Re) 2 HfO 5 ) Zirconium boride (ZrB) 2 ) Gadolinium oxide (Gd) 2 O 3 ) And the like. Ceramic-based neutron absorbing materials, particularly oxide ceramics, have relatively low thermal conductivities, typically below 5W/m-K. This can lead to problems with excessive temperature in the center of the pellet and severe swelling. While boron-containing ceramic neutron absorbing materials can produce helium (He) release with the risk of elevated pressure leakage within the cladding. The most widely used boron carbide ceramic absorber materials also present a risk of oxidative combustion.
The neutron absorbing material composed of the metal matrix composite material can exert the advantages of the metal matrix. The most widely used is aluminum-based boron carbide composite materials, which are used for spent fuel shelves, transport containers, shielding materials and the like. Boron carbide powder and the like can be prepared into a plate or the like by a method such as melt casting (chinese patent application No. 200380102059.1), hot rolling (chinese patent application No. 201410189827.1), hot isostatic pressing (chinese patent application No. 201610820526.3) and the like. The use of increasing the loading of boron carbide in metallic aluminum or aluminum alloys in these processes is one direction (chinese application No. 201410189827.1). The metal institute of Chinese science and engineering physical institute of China and the like. Generally, the design structure of the neutron absorbing material by compounding metal and dense ceramic microspheres and the invention patent of the corresponding application mode are rarely reported at present, and the advantages of the ceramic technology in the aspect of neutron absorbing material manufacturing are not fully exerted.
Disclosure of Invention
To this end, the present inventors have proposed a method for preparing a metal/ceramic microsphere composite neutron absorbing material comprising a continuous phase formed of a metal matrix and ceramic microspheres dispersed in the metal matrix as a dispersed phase, according to the metal characteristics and the need of ceramic as a neutron absorber; the main component of the ceramic microsphere is rare earth oxide;
the preparation method of the metal/ceramic microsphere composite neutron absorption material comprises the following steps: the metal/ceramic microsphere composite neutron absorbing material is prepared by taking metal powder and ceramic microspheres as raw materials, uniformly mixing, and then carrying out hot-pressing sintering; the temperature of the hot press sintering is below the melting point of the metal, and the pressure of the hot press sintering is 10-30 MPa.
The invention provides a hot-pressing sintering process, which can realize tight package and encapsulation of the ceramic microspheres by metal below the melting point.
Preferably, the hot press sintering temperature is 200-300 ℃ lower than the melting point of the metal.
Preferably, the composition of the metal powder is Cu, ti, zr, fe or at least one of the alloy thereof; the particle size of the metal powder is nano-scale, preferably 50-800 nm.
Preferably, the ceramic microspheres comprise a component selected from rare earth aluminate-based ceramics and/or rare earth titanate-based ceramics, preferably selected from the group consisting of ReAlO 3 、Re 3 AlO 12 、Re 4 Al 2 O 9 、Re 2 TiO 5 Wherein the rare earth element Re is at least one of Tm, tb, dy and Gd; the ceramic microspheres account for 2 to 30 percent of the total mass of the metal powder and the ceramic microspheres.
Preferably, the granularity of the ceramic microspheres is 20-120 meshes, preferably 40-100 meshes; the relative density of the ceramic microsphere is 90% -100%.
Preferably, the preparation method of the ceramic microsphere comprises the following steps: weighing Re according to the stoichiometric ratio of ceramic microspheres 2 O 3 、Al 2 O 3 、TiO 2 Mixing, dry-pressing to form, presintering, crushing, ball milling to obtain balls, densification sintering and sieving (not shown in figure 1) to obtain the ceramic microspheres;
alternatively, re is weighed according to the stoichiometric ratio of the ceramic microspheres 2 O 3 、Al 2 O 3 、TiO 2 And mixing, and then carrying out dry press molding, presintering, crushing, densification sintering, ball milling, ball manufacturing and sieving (not shown in fig. 1) to obtain the ceramic microspheres. The invention provides a method for preparing ceramic microspheres by two-step sintering, and then hot-pressingA method for preparing metal/ceramic microsphere base material by sintering. The ceramic microsphere is pre-sintered at a relatively low temperature, so that the problems of high ceramic strength and difficult crushing after direct densification sintering can be avoided.
Preferably, the presintering temperature is 1000-1400 ℃ and the presintering time is 1-4 hours.
Preferably, the densification sintering temperature is 300-500 ℃ higher than the presintering temperature, and the time is 1-6 hours.
Preferably, the ceramic microspheres are dispersed in a dense metal matrix to form a metal-coated ceramic microsphere structure.
The beneficial effects are that:
(1) The method can prepare the metal matrix continuous phase by twice normal pressure sintering and once vacuum hot pressing sintering, and the ceramic microsphere is a metal/ceramic microsphere composite neutron absorbing material of a disperse phase. The manufacturing process has lower cost, and is more applicable to brittle ceramic particles compared with methods such as hot rolling, melting and the like;
(2) The block with certain strength is prepared by adopting a presintering method, and then crushing and ball making treatment are carried out, so that the problem that the ceramic after direct sintering is too high in mechanical strength and difficult to crush and refine can be avoided;
(3) The invention adopts a hot pressing process, and the ceramic can be packaged and wrapped in vacuum for seven minutes under the melting point. And the ceramic microspheres have higher density, and oxide ceramic particles have higher chemical stability under accident conditions. The high-fault-tolerance performance of the gas-free reactor can be realized in the pressurized water reactor environment, and compared with boron carbide, the high-fault-tolerance gas-free reactor can not generate gas release;
(3) Compared with powder particles, the aluminate or titanate ceramic microspheres have better fluidity, are easy to uniformly disperse in a metal matrix, and reduce the linear density deviation of neutron absorbing materials;
(4) Compared with pure ceramics, the metal/ceramic microsphere composite neutron absorption material takes metal as a matrix, so that the processing problems caused by brittleness and microscopic defects of the ceramic material can be avoided, and the manufacturing cost is obviously reduced;
(5) The ceramic microsphere provided by the invention is used as a neutron absorber, the components and the content of the ceramic microsphere can be flexibly designed according to the burnup curve and the life cycle of a control rod, and the fixed burnup curve caused by single ceramic composition is avoided.
Drawings
FIG. 1 is a schematic process flow diagram of the method;
FIG. 2 is a schematic illustration of the arrangement of a metal/ceramic composite neutron absorbing material in a control rod cladding
FIG. 3 is a diagram of DyAlO after pre-sintering of example 1 3 Is a ceramic block of (a);
FIG. 4 example 1 sintered compact DyAlO 3 Ceramic microspheres
FIG. 5 is a photograph of a Cu-based ceramic microsphere composite neutron absorbing material in example 1;
FIG. 6 is a photograph of Zr-based ceramic microspheres composite neutron absorbing material of example 2;
FIG. 7 is a photograph of Zr-based ceramic microspheres composite neutron absorbing material particles in example 2;
FIG. 8 is a Ti-based (Tb, dy) AlO 3 Photographs of ceramic microspheres of composite structure;
FIG. 9 is a diagram showing Tm after burn-in 2 TiO 5 Block samples were taken.
Detailed Description
The invention is further illustrated by the following embodiments, which are to be understood as merely illustrative of the invention and not limiting thereof.
In the present disclosure, rare earth aluminate and rare earth titanate ceramic microspheres are encapsulated in a metal matrix, while utilizing the advantages of high thermal conductivity and easy processing of the metal, and utilizing rare earth elements contained in the dense and better-fluidity ceramic microspheres as neutron absorbers. The components and content of the ceramic microspheres can be designed according to the burn-up of the absorber.
The metal matrix is selected from Cu, ti, zr, fe and one of alloys of the metals. The metals or the corresponding alloys have high heat conductivity coefficient, good processability, and small thermal neutron absorption cross section response (Cu: 3.78barn, ti:6.1barn, zr:0.18 barn, fe:2.56 barn) without introducing the materialsAnd the material design is facilitated due to the large negative reactivity. The ceramic microspheres are 20-120 mesh ceramic fine particles, preferably 40-100 mesh particles, and the density is more than 90%. Ceramic microspheres made from rare earth aluminate-based and titanate-based ceramics including ReAlO 3 (perovskite phase), re 3 Al 5 O 12 (garnet phase), re 4 Al 2 O 9 (monoclinic phase), re 2 TiO 5 The rare earth element Re (fluorite type) may be one or a combination of Tm, tb, dy, gd.
The ceramic microspheres are not simple mixtures of oxide powders, but ceramic microspheres (shapes) with better flowability after sintering densification. The ceramic microspheres form a disperse phase in metal and are wrapped by a metal matrix, so that the ceramic microspheres have the characteristics of high heat conduction, corrosion resistance and the like of metal materials, and the problems of brittleness, poor heat conduction, difficult processing and the like of single ceramic materials in application are avoided.
The invention provides a preparation method of a metal/ceramic microsphere composite neutron absorbing material, which takes a continuous phase of metal as a matrix and compact ceramic microsphere particles as a disperse phase. The ceramic microsphere has rare earth oxide as main component and neutron absorption function. The material can comprehensively utilize the respective advantages of metal and ceramic, and has good fault tolerance performance.
Fig. 1 is a process flow diagram of the method. Referring to fig. 1, a method for preparing the metal/ceramic microsphere composite neutron absorbing material is described in detail.
The metal/ceramic microsphere composite neutron absorbing material is prepared by adopting metal powder and sintered rare earth oxide ceramic microspheres as raw materials, uniformly mixing the two raw materials, and then carrying out a hot-pressing sintering process.
In an alternative embodiment, the metal powder particle size is nano-sized, preferably 50-800 nm. The composition of the metal powder is Cu, ti, zr, fe and one of the alloys of the metals. These metals or corresponding alloys have a high thermal conductivity and good processability.
In an alternative embodiment, the rare earth oxide ceramic microspheres are aluminates or titanates,preferred composition is ReAlO 3 、Re 3 AlO 12 、Re 4 Al 2 O 9 、Re 2 TiO 5 The rare earth element Re may be one or a combination of Tm, tb, dy, gd. The content of aluminate or titanate ceramics in the metal matrix may vary depending on the absorption value. The ceramic microspheres may be present in an amount of 2 to 30wt%. For example, reAlO 3 The content of (C) is preferably 10 to 20wt%. For example Re 3 AlO 12 The content of (C) is preferably 8 to 15wt%. For example Re 4 Al 2 O 9 The content of (C) is preferably 6 to 12% by weight. For example Re 2 TiO 5 The content of (C) is preferably 10 to 15wt%.
And obtaining compact ceramic microspheres by adopting a twice sintering mode. Specifically, the ceramic microspheres are prepared by the steps of: presintering, pelletizing, densification sintering and sieving. Firstly by mixing the raw materials (Re 2 O 3 Powder, tiO 2 Powder, al 2 O 3 Powder) is subjected to ball milling or mechanical stirring and mixing. And drying the mixed and refined powder, and performing dry pressing forming and presintering. The presintering can be carried out in a muffle furnace, and the temperature is 300-500 ℃ lower than the densification sintering temperature. As an example, the temperature is 1000-1400℃and the time is 1-4 hours. The pre-sintered blocks form a stable phase and have a certain strength, and then the pre-sintered blocks are mechanically crushed. The refining and mixing can be carried out by adopting a ball milling or mechanical stirring method, and preferably adopts a ball milling and mixing method. Wherein, the order of densification sintering and ball milling can be changed. The invention provides a method for preparing ceramic microspheres by adopting two-step sintering and preparing metal/ceramic microsphere base materials by hot-pressing sintering. The ceramic microsphere is pre-sintered at a relatively low temperature, so that the problems of high ceramic strength and difficult crushing after direct densification sintering can be avoided. Wherein, the temperature selection of presintering needs to be optimized according to a specific material system, the presintering aims at synthesizing, avoiding the excessive shrinkage ratio and the excessive strength caused by one-step sintering, and breaking difficulty,thereby affecting the preparation of the microspheres. Presintering will typically be 300-500 ℃ lower than densification sintering temperature. If the pre-sintering temperature is too low, the synthesis cannot be achieved. Such as: re (Re) 2 O 3 And Al 2 O 3 If the reaction temperature is too low, the pre-sintering is not performed.
Sintering the mechanically crushed particles at a densification sintering temperature, ball milling the sintered particles again for 1-3 hours (preferably 1-2 hours) to form ceramic microspheres, and screening ceramic microsphere particles with proper granularity. Of course, the ball making and screening may also be performed after the burn-in step. As one example, mechanically broken particles are ball milled for 1-3 hours with alumina or zirconia balls to form ceramic microspheres with smooth corners.
In an alternative embodiment, the ceramic microspheres are screened by adopting a nylon net or a metal net with corresponding mesh numbers. The granularity of the ceramic microspheres is 20-120 meshes, preferably 40-100 meshes. The ceramic microspheres have a relative density of 90 to 100%, preferably greater than 95%.
In an alternative embodiment, the hot press sintering temperature is below the melting point of the metal (preferably, the hot press sintering temperature is 200-300 ℃ below the melting point of the metal or alloy), and the hot press pressure may be 10-30 MPa. If the hot press sintering temperature continues to decrease, the metal material cannot be fully densified, a dense structure cannot be formed and a large number of holes are contained; adverse consequences: firstly, the thermal conductivity is reduced, secondly, the strength is reduced, and thirdly, the corrosion of the materials by the mediums such as the moderator, the coolant and the like under the accident condition can be greatly accelerated.
The invention provides a metal/ceramic microsphere composite neutron absorption material, wherein the composition and proportion of ceramic microspheres can be adjusted according to the requirement of neutron absorption value and can be loaded in a nuclear reactor control rod bundle. FIG. 2 is a schematic illustration of the arrangement of a metal/ceramic composite neutron absorbing material in a control rod cladding. In the invention, the laser pulse method is adopted to test that the thermal conductivity of the composite neutron absorbing material of the ceramic microsphere is 10-220W/m.K from room temperature to 1273K.
The present invention will be further illustrated by the following examples. It is also to be understood that the following examples are given solely for the purpose of illustration and are not to be construed as limitations upon the scope of the invention, since numerous insubstantial modifications and variations will now occur to those skilled in the art in light of the foregoing disclosure. The specific process parameters and the like described below are also merely examples of suitable ranges, i.e., one skilled in the art can make a suitable selection from the description herein and are not intended to be limited to the specific values described below.
Example 1: cu-based DyAlO 3 Ceramic microsphere neutron absorbing material
According to the mole ratio of 1:1 weighing Dy 2 O 3 And alumina powder, adding water or ethanol, ball milling for 4-20 hr, and obtaining alumina balls with purity greater than 99%. The powder after ball milling is dried at 80 ℃, then is dried and pressed by a steel die, and the block after dry pressing is subjected to cold isostatic pressing treatment and then presintered for 2 hours at 1300 ℃. Fig. 3 is a photograph of a sample of the ceramic block after burn-in. The burned blocks are crushed into particles through mechanical beating, the particles are densely sintered for 2 to 10 hours at 1600 ℃ after being collected, the sintered powder is ball-milled for about 1 hour by adopting an alumina grinding ball, and then the nylon screen is used for screening out microspheres with the granularity of 40 to 100 meshes. FIG. 4 is a photograph of the screened 40-60 mesh ceramic microspheres. The microspheres are added into copper powder with the size of 200nm, ball milling and mixing are carried out for 10-20 minutes, then drying and dry pressing are carried out for forming, and then hot pressing sintering is carried out for 2 hours in vacuum atmosphere at the temperature of 600 ℃ and the pressure of 20MPa, thus obtaining the metal/ceramic composite neutron absorbing material. FIG. 5 is a Cu/DyAlO 3 Round rods of ceramic microsphere neutron absorbing material having a thermal conductivity in the range of from room temperature to 1273K of more than 200W/mK, which is more than one order of magnitude higher than that of pure aluminate ceramics (e.g. GdAlO 3 The thermal conductivity of the ceramic is only 3.5W/mK at 500 ℃, dyAlO 3 Lower).
Example 2: zr-based (Tb, dy) AlO 3 Ceramic microsphere neutron absorbing material
Adopting Zr-4 alloy as a matrix and perovskite phase (Tb, dy) AlO 3 Ceramic microspheresThe zirconium-based ceramic microsphere composite neutron absorbing material with the ceramic mass content of 10% is prepared as the neutron absorbing material. Tb of 2 O 3 And Dy 2 O 3 Powder according to 1:1, carrying out mixed ball milling, then carrying out dry pressing, carrying out cold isostatic pressing treatment on the blocks after the dry pressing, carrying out presintering treatment at 1200 ℃, and obtaining the particles by adopting a mechanical crushing method. After the particles are collected, densification sintering is carried out for 2-10 hours at 1590 ℃, the sintered powder is ball-milled for about 2 hours by adopting alumina grinding balls, and then the nylon screen is used for screening out microspheres with 20-120 meshes. The microspheres and Zr-4 powder are mixed and sintered for 1 hour under vacuum hot pressing at 1000 ℃ and 20MPa, and a sample of the composite material is obtained as shown in figure 6. The metal color of the zirconium alloy is seen, and ceramic microspheres are distributed on the surface at intervals. The thermal conductivity of the material exceeds 7W/m.K from room temperature to 1273K. Fig. 7 shows a scanning electron micrograph of the microstructure of the composite material, in which the microspheres are encapsulated in a Zr metal matrix to form a dispersed phase.
Example 3: ti-based (Tb, dy) AlO 3 Ceramic microsphere neutron absorbing material
Ti alloy is used as a matrix, and Tb, dy AlO of perovskite phase is adopted 3 The ceramic microspheres are neutron absorber materials, and the zirconium-based ceramic microsphere composite neutron absorber material with the ceramic mass content of 12% is prepared. Tb of 2 O 3 And Dy 2 O 3 Powder according to 1:1, carrying out mixed ball milling, then carrying out dry pressing, carrying out cold isostatic pressing treatment on the blocks after the dry pressing, carrying out presintering treatment at 1200 ℃, and obtaining the particles by adopting a mechanical crushing method. After the particles are collected, densification sintering is carried out for 2-10 hours at 1620 ℃, the sintered powder is ball-milled for about 2 hours by adopting an alumina grinding ball, and then the nylon screen is used for screening out microspheres with 20-120 meshes. The microspheres and Zr-4 powder are mixed and sintered for 1.5 hours under vacuum hot pressing at 1200 ℃ and 20MPa, so as to obtain a sample of the composite material. FIG. 8 shows the morphology of ceramic microspheres added to a matrix, with dimensions of about 200 microns, and relatively uniform. The thermal conductivity of the material is more than 10W/mK from room temperature to 1273K and is also higher than that of pure aluminate ceramics (2-5W/mK).
Example 4: fe-based Tm 2 TiO 5 Ceramic microsphere neutron absorbing material
Adopts stainless steel as a matrix, tm 2 TiO 5 The ceramic microspheres are neutron absorber materials, and the stainless steel-based ceramic microsphere composite neutron absorber material with the ceramic mass content of 8% is prepared. Tm is to 2 O 3 And TiO 2 Powder is prepared according to the molar ratio of 1:1, mixing and ball milling, then dry pressing, and carrying out cold isostatic pressing treatment on the block body after the dry pressing, and presintering treatment at 1100 ℃. FIG. 9 is a diagram showing Tm after burn-in 2 TiO 5 Photographs of the ceramic samples. And mechanically crushing the presintered body to obtain particles. After the particles are collected, densification sintering is carried out for 2-10 hours at 1480 ℃, the sintered powder is ball-milled for about 2 hours by adopting zirconia grinding balls, and then the nylon screen is used for screening out microspheres with the granularity of 40-100 meshes. The microspheres and stainless steel powder are mixed and sintered for 2 hours under vacuum hot pressing at 1000 ℃ and 30MPa, so that a sample of the composite material is obtained. The thermal conductivity of the given material is more than 10W/m.K from room temperature to 1273K and is also higher than that of pure titanate ceramics.
Example 5
A metal/ceramic microsphere composite neutron absorbing material was prepared with reference to example 1, except that: respectively set DyAlO 3 The content of the ceramic microspheres is 5wt%, 10wt%, 15wt% and 25wt%.

Claims (8)

1. The preparation method of the metal/ceramic microsphere composite neutron absorbing material is characterized in that the metal/ceramic microsphere composite neutron absorbing material comprises a continuous phase formed by a metal matrix and ceramic microspheres which are dispersed in the metal matrix and serve as a disperse phase; the main component of the ceramic microsphere is rare earth oxide;
the preparation method of the metal/ceramic microsphere composite neutron absorption material comprises the following steps: the metal/ceramic microsphere composite neutron absorbing material is prepared by taking metal powder and ceramic microspheres as raw materials, uniformly mixing, and then carrying out hot-pressing sintering; the temperature of the hot press sintering is below the melting point of the metal, and the pressure of the hot press sintering is 10-30 MPa.
2. The method according to claim 1, wherein the hot press sintering temperature is 200 to 300 ℃ lower than the melting point of the metal.
3. The method of claim 1, wherein the metal powder has a composition of at least one of Cu, ti, zr, fe and an alloy thereof; the particle size of the metal powder is nano-scale, preferably 50-800 nm.
4. A method according to any of claims 1-3, characterized in that the components of the ceramic microspheres are selected from rare earth aluminate-based ceramics or/and rare earth titanate-based ceramics, preferably from ReAlO 3 、Re 3 AlO 12 、Re 4 Al 2 O 9 、Re 2 TiO 5 Wherein the rare earth element Re is at least one of Tm, tb, dy and Gd; the ceramic microspheres account for 2 to 30 percent of the total mass of the metal powder and the ceramic microspheres.
5. The method according to claim 4, wherein the ceramic microspheres have a particle size of 20 to 120 mesh, preferably 40 to 100 mesh; the relative density of the ceramic microsphere is 90% -100%.
6. The method of claim 4, wherein the method of preparing ceramic microspheres comprises: weighing Re according to the stoichiometric ratio of ceramic microspheres 2 O 3 、Al 2 O 3 、TiO 2 Mixing, dry-pressing to form, presintering, crushing, ball milling to form balls, densification sintering and sieving to obtain the ceramic microspheres;
alternatively, re is weighed according to the stoichiometric ratio of the ceramic microspheres 2 O 3 、Al 2 O 3 、TiO 2 And mixing, dry-pressing, pre-sintering, crushing, densification sintering, ball milling, ball making and sieving to obtain the ceramic microspheres.
7. The method according to claim 6, wherein the pre-firing temperature is 1000 to 1400 ℃ for 1 to 4 hours.
8. The method according to claim 7, wherein the densification sintering is performed at a temperature 300 to 500 ℃ higher than the pre-sintering temperature for 1 to 6 hours.
CN202211524206.5A 2022-11-30 2022-11-30 Preparation method of metal/ceramic microsphere composite neutron absorption material Pending CN117066509A (en)

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