CN104140259A

CN104140259A - Method for quickly manufacturing Li2TiO3 tritium breeding small balls

Info

Publication number: CN104140259A
Application number: CN201410369142.5A
Authority: CN
Inventors: 严有为; 薛丽红; 李和平; 周启来
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2014-07-30
Filing date: 2014-07-30
Publication date: 2014-11-12
Anticipated expiration: 2034-07-30
Also published as: CN104140259B

Abstract

The invention provides a method for quickly manufacturing Li2TiO3 tritium breeding small balls. The method comprises the following steps that (1) Li2TiO3 powder and binder powder are mixed to form mixed powder; (2) a small ball three-dimensional model is established in a computer and is stored in the format of STL; (3) the mixed powder obtained in the step (1) is transferred into 3D printing equipment, the small ball three-dimensional model in the format of STL is introduced into a system of the 3D printing equipment; (4) technological parameters are set and the 3D printing equipment is started to obtain small ball entities; (5) the small ball entities are placed into a cold isostatic press to be compacted; (6) binder removal processing is conducted on the small ball entities; (7) the small ball entities are sintered in a sintering furnace. The Li2TiO3 small balls manufactured through the method are high in degree of sphericity, compactness and crushing strength, and large-scale and mechanical production of the Li2TiO3 tritium breeding small balls can be realized.

Description

A kind of quick preparation Li 2tiO 3the method of tritium propagation bead

Technical field

The present invention relates to 3D and print field, particularly a kind of 3D of utilization printing technique is prepared Li fast ₂tiO ₃the method of tritium propagation bead.

Background technology

Along with society and economic development, the demand of the energy is increased day by day.For the final energy problem that solves, people have turned to nucleosynthesis by sight.Fusion reaction is compared with fission reaction, and the radiation causing in reaction process is less, compares with sun power with wind energy, and its energy density is larger.Therefore, nucleosynthesis is undoubtedly optimal green high-efficient production capacity mode.Comprise in the world that seven countries of China and unit have jointly signed ITER and be designed for research and realize nucleosynthesis generating in November, 2006.The starting material of fusion reaction are two kinds of isotropic substance deuteriums and the tritiums of hydrogen, and deuterium can extract from seawater, and resource is compared with horn of plenty.Tritium be the high-energy neutron that produces by nucleosynthesis after suitable slowing down, bombardment tritium multiplication agent ( ⁶li, ⁷li) constantly produce tritium gas, to realize controlling oneself of tritium.

Be rich in ⁶the lithium-based ceramic Li of Li ₂tiO ₃, there is higher lithium atom density, low reactivity, excellent chemical stability and good tritium release performance, be considered to one of solid tritium multiplication agent of tool future, receive domestic and international investigator's concern.Due to microspheroidal tritium multiplication agent, there is the features such as convenient filling, easy recovery, and there is larger specific surface area, good permeability, be conducive to diffusion and the release of tritium, therefore, prepare the emphasis that the uniform tritium propagation of high sphericity, high-compactness, size distribution bead becomes research.

Li ₂tiO ₃the preparation method of bead has multiple, is conventionally divided into mechanical process and wet method, and at present, studying more is wet processing.The primary process of wet method is by Li ₂tiO ₃powder and binding agent are mixed into ceramic size, then splash in solidifying agent by needle tubing, utilize the surface tension of drop to form bead, then obtain ceramic bead after binder removal sintering.Through continuous research with improve, adopt that wet method can obtain that footpath is little, any surface finish, bead that sphericity is higher.

But wet method is to operator and the requirement of needle tubing bore is high, bead balling ratio is not high, experimental repeatability is poor, bead size distribution is wide, is difficult to realize automatization, the production in enormous quantities of bead.Therefore, seek a kind of stable high Li that changes fast and automatically ₂tiO ₃ceramic bead preparation method has important scientific meaning and practical value.

Summary of the invention

The object of the present invention is to provide quick preparation Li ₂tiO ₃the method of tritium propagation bead, the Li of preparation ₂tiO ₃bead has high sphericity, high-compactness and high crushing strength, can realize Li ₂tiO ₃extensive, the mechanization production of tritium propagation bead.

A kind of quick preparation Li ₂tiO ₃the method of tritium propagation bead, comprises the following steps:

(1) by Li ₂tiO ₃powder and adhesive powder mixed preparing mixed powder, in mixed powder, the weight percentage of each composition is respectively: Li ₂tiO ₃powder 70～90wt%, adhesive powder 10～30wt%;

(2) in computer, set up bead three-dimensional model, the diameter of single bead three-dimensional model is 1～10mm, and the number of bead three-dimensional model is set as 1～1000, and saves as STL form;

(3) mixed powder in step (1) is transferred in 3D printing device, and the bead three-dimensional model of STL form is imported in the system of 3D printing device;

(4) set processing parameter and open 3D printing device, the processing parameter of 3D printing device is as follows: laser power 10～50W, and lasing beam diameter 100～300 μ m, sweep span 100～300 μ m, scanning speed 1000～3000mm/s, obtains bead entity;

(5) the bead entity of step (4) gained is put into cold isostatic press densification, the pressure applying to bead entity is 100～600MPa, and the dwell time is 20～60min;

(6) the bead entity of processing through step (5) is moved in resistance furnace and carries out binder removal processing, at 250～700 ℃ of temperature, be incubated 1～2h;

(7) the bead entity of processing through step (6) is carried out to sintering in sintering oven, sintering temperature is 600～1000 ℃, and soaking time is 1.5～3h.

As preferably, the material that described adhesive powder is selected is epoxy resin, stearic acid or nylon.

Technique effect of the present invention is embodied in:

The present invention is applied to Li by 3D printing technique ₂tiO ₃the preparation of bead.According to set up different models in computer, can one time to produce tens to thousands of beads, realized Li ₂tiO ₃efficient, controlled preparation.Whole preparation process is completed by 3D printing device, is conducive to Li ₂tiO ₃stable and the mass production of bead.The Li preparing by this method ₂tiO ₃the density of bead is higher, and size distribution is even, and crystal grain is tiny, and crystal grain and intergranule exist a fixed gap, be conducive to tritium gas by bead internal divergence to surface.

Accompanying drawing explanation

Fig. 1 is process flow diagram of the present invention;

Fig. 2 is 3D print procedure schematic diagram of the present invention;

Fig. 3 (a), (b) are respectively three-dimensional model diagram and the laser sintered procedure chart of embodiment 1;

Fig. 4 is the SEM figure of the sample of embodiment 1 preparation;

Fig. 5 is that the sample density of embodiment 2 preparations is with the Changing Pattern figure of sintering temperature;

Fig. 6 is the SEM figure of the sample of embodiment 2 preparations;

Fig. 7 is the SEM figure of the sample of embodiment 3 preparations.

Embodiment

Embodiment 1:

By the Li of 25g ₂tiO ₃the adhesive powder of powder and 2.78g evenly mixes (adhesive powder select material be epoxy resin, stearic acid or nylon), be laid on 3D printing device worktable, then by bead three-dimensional model (diameter 4mm, STL form) import in the system of 3D printing device, set equipment parameters (laser power: 20W, lasing beam diameter: 200 μ m, sweep span: 200 μ m, scanning speed: 2000mm/s), start successively scanning.The bead entity obtaining is transferred in cold isostatic press, and applying pressure is 300MPa, and pressurize 30min obtains comparatively fine and close bead entity.Then bead entity is moved in resistance furnace and carries out binder removal processing, after cooling, sintering in High Temperature Furnaces Heating Apparatus, sintering temperature is 850 ℃, soaking time is 2h, obtains Li ₂tiO ₃bead entity.

Fig. 2 is the process schematic diagram that 3D of the present invention prints bead entity, and 3D prints bead entity and completed by computer controlled automatic.

Fig. 3 (a), (b) are respectively three-dimensional model diagram and the laser sintered procedure chart of embodiment 1.As can be seen from Figure 3 the method for, printing by 3D can realize Li easily and fast ₂tiO ₃the preparation of bead.

The density of measuring bead entity prepared by this embodiment through Archimedes's drainage is 90%; The crushing strength of testing bead entity prepared by this example by universal testing machine is 36N.

Fig. 4 is the SEM photo of the bead entity prepared in embodiment.Therefrom can find out Li ₂tiO ₃bead size of microcrystal is little, be about 1 μ m, and hole is less, comparatively fine and close.

Embodiment 2:

By the Li of 25g ₂tiO ₃the adhesive powder of powder and 6.25g evenly mixes (adhesive powder select material be epoxy resin, stearic acid or nylon), be laid on 3D printing device worktable, then by bead three-dimensional model (diameter 4mm, STL form) import in system, set equipment parameters (laser power: 20W, lasing beam diameter: 200 μ m, sweep span: 200 μ m, scanning speed: 2000mm/s), start successively scanning.The bead entity obtaining is transferred in cold isostatic press, and applying pressure is 300MPa, and pressurize 30min obtains comparatively fine and close bead entity.Then bead entity is moved in resistance furnace and carries out binder removal processing, after cooling, sintering in High Temperature Furnaces Heating Apparatus, sintering temperature is 650～950 ℃, soaking time is 2h, obtains Li ₂tiO ₃bead entity.

Through Archimedes's drainage, measure in this embodiment, when sintering temperature is 850 ℃, the density of the bead entity of preparation is 83.3%; The crushing strength of testing bead entity prepared by this example by universal testing machine is 28N.

Fig. 5 prepares the density of bead entity with the Changing Pattern of sintering temperature in example, can find out, when sintering temperature is increased to 850 ℃ by 650 ℃, density obviously improves; Continue after rising sintering temperature to 950 ℃, the density of bead entity changes not obvious.So in this embodiment, the optimal sintering temperature of bead entity is 850 ℃.

Fig. 6 prepares the SEM photo of bead entity in this example, as can be seen from the figure, and Li ₂tiO ₃crystal grain is tiny evenly, and size of microcrystal is about 1 μ m left and right, and crystal grain and intergranule exist a fixed gap.

Embodiment 3:

By the Li of 25g ₂tiO ₃the epoxy powder of powder and 10.7g evenly mixes, be laid on 3D printing device worktable, then by bead three-dimensional model (diameter 4mm, STL form) import in system, set equipment parameters (laser power: 20W, lasing beam diameter: 200 μ m, sweep span: 200 μ m, scanning speed: 2000mm/s), start successively scanning.The bead entity obtaining is transferred in cold isostatic press, and applying pressure is 300MPa, and pressurize 30min obtains comparatively fine and close bead entity.Then bead entity is moved in resistance furnace and carries out binder removal processing, after cooling, sintering in High Temperature Furnaces Heating Apparatus, sintering temperature is 850 ℃, soaking time is 2h, obtains Li ₂tiO ₃bead entity.

The density of measuring bead entity prepared by this embodiment through Archimedes's drainage is 78.1%; The crushing strength of testing bead entity prepared by this example by universal testing machine is 17N.

Fig. 7 is the SEM photo of preparing bead entity in example, as can be seen from the figure, and the Li preparing under this embodiment ₂tiO ₃the space of bead entity is more, Li ₂tiO ₃crystal grain is tiny, and particle diameter is about 500nm, is a kind of typical porous nanocrystalline pottery.

Those skilled in the art will readily understand; the foregoing is only preferred embodiment of the present invention; not in order to limit the present invention, all any modifications of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims

1. prepare fast Li for one kind ₂tiO ₃the method of tritium propagation bead, is characterized in that: comprise the following steps:

2. a kind of quick preparation Li according to claim 1 ₂tiO ₃the method of tritium propagation bead, is characterized in that: the material that described adhesive powder is selected is epoxy resin, stearic acid or nylon.