CN114774706A

CN114774706A - Controlled synthesis process of functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining

Info

Publication number: CN114774706A
Application number: CN202210441010.3A
Authority: CN
Inventors: 楼华山; 纪红伟; 赵冬冬; 陈文勇; 陈冬玲; 李宏军; 王大红; 冯艺; 莫文锋; 吴坤; 陈华; 关来德; 高茂涛; 龚荣; 李海安; 思常红; 李骏鹏; 李杨; 汤耀年; 阙燚彬
Original assignee: Liuzhou Vocational and Technical College
Current assignee: Liuzhou Vocational and Technical College
Priority date: 2022-04-25
Filing date: 2022-04-25
Publication date: 2022-07-22
Anticipated expiration: 2042-04-25
Also published as: CN114774706B

Abstract

The invention provides a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining, which comprises the following steps: providing a pore-forming template, putting the coke powder and the pore-forming template into a mold sheath, and performing isostatic pressing to obtain a rotor blank; putting the rotor blank into a roasting furnace for sintering to convert the rotor blank into a carbonized composite material; placing the carbonized composite material into a graphitization furnace for graphitization sintering, so that the carbonized composite material is converted into a graphite composite material; the graphite composite material is immersed in the corrosive liquid to remove the annular hollow-out body and the branches of the metal material. The graphite composite material with an ordered macroporous (less than or equal to 1mm) structure can be prepared, and on the basis, the functionalized graphite composite material is applied to the development of a graphite rotor with a small nozzle aperture (less than or equal to 1mm), so that the bottleneck of the prior art is broken through, and the quality of an aluminum melt is further improved.

Description

Control synthesis process of functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining

Technical Field

The invention relates to a novel graphite composite material preparation technology, in particular to a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining.

Background

The high-purity compact graphite material has the advantages of excellent high-temperature mechanical property, good thermal shock resistance, corrosion resistance and the like, so that the high-purity compact graphite material is widely applied to the fields of metallurgy and the like. For example, the aluminum processing industry generally selects high-purity compact graphite materials to prepare graphite rotors with regular pore channel structures, and the graphite rotors are used as key components of a dehydrogenation device to purify aluminum melt.

The effect of the graphite rotor for purifying the aluminum melt is mainly determined by the internal pore structure, the pore size and the like of the graphite rotor, because the reasonably distributed pore structure can effectively prevent the graphite rotor nozzle from spraying the gas flux (N) of the aluminum melt₂Etc.) the phenomenon of "bubble coalescence" occurs; the smaller the pore diameter, the more a gas flux (N) is injected into the aluminum melt through a graphite rotor nozzle₂Etc.) the smaller the diameter of the formed bubbles is, the better the dispersion effect of the bubbles is after the bubbles are further broken by the rotating graphite rotor, the more beneficial the hydrogen in the aluminum liquid is to efficiently diffuse into the bubbles and be taken out of the liquid surface along with the upward floating of the bubbles.

Therefore, how to effectively control the pore structure and the pore size and prepare the graphite rotor with the nozzle with smaller pore size has important significance. However, due to the limitations of the existing processing technology, it is very difficult to process a nozzle with a diameter of less than or equal to 1mm on a graphite rotor with a diameter of greater than or equal to 200mm, which results in a large bubble diameter and low dehydrogenation efficiency formed by the conventional graphite rotor nozzle.

Disclosure of Invention

Aiming at the problems in the background art, the invention provides a controlled synthesis process of a functionalized ordered macroporous (less than or equal to 1mm) graphite rotor for aluminum alloy refining, which can prepare the graphite rotor with the ordered macroporous (less than or equal to 1mm) structure.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining comprises the following steps:

providing a pore-forming template: the pore-forming template comprises a trunk, a plurality of groups of branches connected to the periphery of the trunk in a surrounding manner and annular hollow bodies connected to one ends of the plurality of groups of branches opposite to the trunk, wherein the trunk is of a hollow cylinder structure, an organic material is adopted as a material for forming the trunk, the annular hollow bodies are formed by splicing a plurality of connecting rods, and metal is adopted as the material for forming the branches and the annular hollow bodies;

isostatic pressing rotor blank: putting coke powder and the pore-forming template into a mold sheath, and performing isostatic pressing to obtain a rotor blank;

roasting treatment: putting the rotor blank into a roasting furnace for sintering to convert the rotor blank into a carbonized composite material;

graphitizing and sintering treatment: placing the carbonized composite material into a graphitizing furnace for graphitizing sintering so as to convert the carbonized composite material into a graphite composite material;

removing the metal template: and (3) soaking the graphite composite material in corrosive liquid to remove the annular hollow-out body and the branches of the metal material, so as to obtain a macroporous structure of an ordered array in the graphite composite material.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

1. the controlled synthesis process of the functionalized ordered macroporous (less than or equal to 1mm) graphite rotor for aluminum alloy refining utilizes the pore-forming template to play a role of 'pore-forming' in the graphite rotor, the graphite rotor is filled with coke powder and is made into a compact rotor blank by isostatic pressing, the pore-forming template is removed after roasting and graphitization, an ordered macroporous structure can be formed in the graphite composite material, so that the pore-forming function is realized, the pore size of the pore structure formed in the graphite composite material is determined by the size parameter of the pore-forming template, the pore size of the pore structure formed in the graphite composite material can be conveniently adjusted by adjusting the size of the pore-forming template, so that macropores with the pore diameter less than or equal to 1mm are formed in the graphite composite material, and on the basis, the functionalized graphite composite material is applied to the development of the graphite rotor with the pore diameter of a small nozzle (less than or equal to 1mm), thereby breaking through the bottleneck of the prior art level and further improving the quality of the aluminum melt.

Although a porous network structure with a certain pore volume ratio and mechanical properties can be prepared by the traditional template method, the method has the following disadvantages: 1) the traditional template method is difficult to accurately process a network structure with specific pore volume ratio and pore diameter according to the characteristics of the graphite rotor nozzles such as size, distribution position and number; 2) poor rigidity of the whole body, and the like. The pore-forming template adopted by the invention is based on the structural characteristics of the graphite rotor nozzle, the pore-forming template with the shaft tree structure is adopted to fill the interior of a graphite material, when the pore-forming template is removed, the trunk of the pore-forming template forms a main air passage of the graphite rotor, the tree crown part formed by the annular hollow body forms a nozzle of the graphite rotor, and the branches form a ventilation branch which is communicated with the nozzle and the main air passage in the graphite rotor and jointly form a gas passage in the graphite rotor. Through the setting to the size parameter of the trunk, annular fretwork body, the branch of pore-forming template, can reach purposes such as hole interval, aperture size, trompil position of accurate regulation and control graphite rotor nozzle, thereby satisfied the demand of graphite rotor to littleer nozzle aperture, and can conveniently control the pore volume proportion of graphite rotor inside, when lieing in the inside porous structure that forms of graphite rotor, it is great also to ensure the whole rigidity of the graphite material that obtains, in order to satisfy the operation requirement of graphite rotor.

2. The utility model provides a control synthesis technology of above-mentioned aluminum alloy is concise with orderly macropore (≦ 1mm) graphite rotor of functionalization, the trunk of its pore-forming template is through the hollow cylinder of top, N middle hollow cylinder and end hollow cylinder suit constitution in proper order, the octahedron that annular fretwork body constitutes through the connecting rod piles up the concatenation through the mode of three-dimensional array and boolean operation on the space and constitutes, and the trunk, annular fretwork body and branch and trunk plug-in connection, it can conveniently adjust trunk length through changing middle hollow cylinder's quantity, and through piling up direction and quantity to the octahedron that the adjusting connecting rod constitutes, can conveniently adjust the radius and the equidimension such as height of annular fretwork body, and then make the pore-forming template can be applicable to the pore-forming demand of the graphite rotor of different size sizes.

3. According to the controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining, an organic material is used as a material for forming the main body, the main body is of a hollow cylinder structure, and in the roasting and graphitization processes of the graphite material, the thermal stress in the preparation process of the graphite composite material can be eliminated, the graphite composite material is prevented from cracking, and the qualified rate of finished products is improved. The annular hollow body is got rid of the back and forms the nozzle of graphite rotor in graphite combined material, because the aperture of the nozzle of graphite rotor is less (≦ 1mm), leads to constituting the connecting rod diameter of annular hollow body also less, for satisfying the rigidity of "axle tree" structure and getting rid of convenient needs, the connecting rod and the branch that constitute annular hollow body all adopt the powder preparation of metal material.

Drawings

FIG. 1 is a flow chart of a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a graphite rotor to be prepared;

FIG. 3 is a schematic structural view of a rotor blank according to an embodiment of the present invention;

FIG. 4 is a top view structural diagram of a pore-forming template in an embodiment of the present invention;

FIG. 5 is a perspective view of a pore-forming template in an embodiment of the present invention;

FIG. 6 is a perspective view of the stem of the pore-creating template shown in FIG. 5;

FIG. 7 is a perspective view of the central hollow cylinder of the trunk shown in FIG. 5;

FIG. 8 is a perspective view of the central hollow cylinder of FIG. 7 from another perspective;

FIG. 9 is a perspective view of the head hollow cylinder of the stem of FIG. 5 from another perspective;

FIG. 10 is a perspective view of the hollow cylinder of the midsole of FIG. 5;

FIG. 11 is a perspective view of the annular hollow-out body of the pore-creating template shown in FIG. 5;

FIG. 12 is a schematic structural diagram of an octahedron in an annular hollow-out body according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of the annular hollow body at the assembling spherical node according to the embodiment of the present invention;

FIG. 14 is an enlarged view of a part of the structure of the annular hollow body according to the embodiment of the invention;

FIG. 15 is a schematic structural diagram of a stem in the pore-forming template shown in FIG. 5;

fig. 16 is a partial structural object diagram of the annular hollow-out body prepared in embodiment 1 of the present invention;

FIG. 17 is a pictorial view of a branch prepared in example 1 of the present invention;

FIG. 18 is a pictorial representation of a trunk prepared in example 1 of the present invention;

FIG. 19 is a pictorial representation of a pore-forming template that was prepared in accordance with example 1 of the present invention;

FIG. 20 is a pictorial view of a rotor blank obtained by isostatic pressing according to example 1 of the present invention;

FIG. 21 is a drawing of a carbonized composite material obtained by sintering a rotor blank according to example 1 of the present invention;

FIG. 22 is a graph of the morphology of the graphite/Ti-based template interface;

fig. 23 is an X-ray detection image of the internal structure of the graphite composite material prepared in example 1 of the present invention.

Description of the main elements

100. Forming a pore template; 10. a trunk; 11. a head hollow cylinder; 112. a first shaft hole; 114. a first nesting groove; 116. a first mounting groove; 13. a hollow cylinder in the middle; 131. a cylindrical body; 132. inserting the convex column; 133. a second sleeving connection groove; 134. a second shaft hole; 135. a second mounting groove; 15. a bottom hollow cylinder; 151. a cylindrical body; 152. connecting the convex columns; 154. a third shaft hole; 155. a third mounting groove; 16. a hollow cavity; 17. installing a channel; 18. positioning the projection; 19. positioning a groove; 30. branches; 32. a branch rod; 321. a V-shaped rod; 323. a second link; 34. a first link; 50. an annular hollow-out body; 51. a connecting rod; 53. a fan-ring tree crown area; 54. a sector ring lateral branch area; 55. a spherical node; 56. assembling the spherical nodes; 57. an assembly hole; 200. a graphite rotor; 210. a rotor body; 230. an impeller; 250. a nozzle; 300. and (3) a rotor blank.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1 and fig. 4 to 15 together, the present invention provides a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining, comprising the following steps:

step S1, providing a pore-forming template 100: the pore-forming template 100 adopts a shaft tree structure and comprises a main trunk 10, a plurality of groups of branches 30 connected to the periphery of the main trunk 10 in a surrounding manner and an annular hollow body 50 connected to one end of the plurality of groups of branches 30 opposite to the main trunk 10, wherein the main trunk 10 is in a hollow cylindrical structure and adopts an organic material as a material for forming the main trunk 10; the annular hollow-out body 50 is formed by splicing a plurality of connecting rods 51, and metal materials are adopted as the materials of the molded branches 30 and the annular hollow-out body 50.

Specifically, the trunk 10 is formed by sequentially sleeving a top hollow cylinder 11, N middle hollow cylinders 13 and a bottom hollow cylinder 15. The number N of the intermediate hollow cylinders 13 may be set according to the design length of the trunk 10. The head hollow cylinder 11 is internally provided with a first shaft hole 112, a first sleeving groove 114 and a first mounting groove 116 in a penetrating manner, the first shaft hole 112 and the first sleeving groove 114 are coaxially arranged along the axial direction of the head hollow cylinder 11 and are communicated with each other, and the aperture of the first sleeving groove 114 is larger than that of the first shaft hole 112; the first mounting groove 116 is concavely arranged on the bottom surface of the top hollow cylinder 11 facing the middle hollow cylinder 13, extends along the radial direction of the top hollow cylinder 11 and is communicated with the first sleeving connection groove 114. In the present embodiment, the number of the first mounting grooves 116 is plural, and the plural first mounting grooves 116 are provided at intervals around the axial direction of the top hollow cylinder 11.

The middle hollow cylinder 13 comprises a cylinder main body 131 and an inserting convex column 132 convexly arranged on the top surface of the cylinder main body 131, a second sleeving groove 133 is formed in the cylinder main body 131 in a penetrating manner along the axial direction, a second shaft hole 134 is formed in the inserting convex column 132 in a penetrating manner along the axial direction, the second shaft hole 134 and the second sleeving groove 133 are coaxially arranged and are mutually communicated, and the aperture of the second shaft hole 134 is smaller than that of the second sleeving groove 133 so as to form a step hole; second mounting grooves 135 are concavely formed on two opposite end surfaces of the cylindrical main body 131, wherein the second mounting groove 135 closer to the inserting convex column 132 extends along the radial direction of the cylindrical main body 131 and penetrates through the peripheral wall of the inserting convex column 132 to be communicated with the step hole; the second mounting groove 135 located at one side of the cylindrical body 131 opposite to the insertion convex pillar 132 extends along the radial direction of the cylindrical body 131 and is communicated with the second sleeving connection groove 133 of the stepped hole. In this embodiment, a plurality of second mounting grooves 135 are concavely provided on both opposite end surfaces of the cylindrical body 131, and the plurality of second mounting grooves 135 are provided at intervals in the axial direction of the middle hollow cylinder 13.

The bottom hollow cylinder 15 comprises a cylinder body 151 and a connecting convex column 152 convexly arranged on the top surface of the cylinder body 151, the bottom hollow cylinder 15 is provided with a third shaft hole 154 and a third mounting groove 155, and the third shaft hole 154 penetrates through the cylinder body 151 and the connecting convex column 152 along the axial direction of the bottom hollow cylinder 15; the third mounting groove 155 is concavely disposed on an end surface of the cylindrical body 151 close to the insertion boss 132 and extends along a radial direction of the cylindrical body 151 to penetrate the connection boss 152, thereby communicating with the third shaft hole 154. In the present embodiment, the number of the third mounting grooves 155 is plural, and the plural third mounting grooves 155 are provided at intervals around the axial direction of the bottom hollow cylinder 15.

Trunk 10 is through the constitution of top hollow cylinder 11, the hollow cylinder 13 in the middle of N and end hollow cylinder 15 suit in proper order, specifically is: the inserting convex column 132 of the middle hollow cylinder 13 is inserted into the second sleeving groove 133 of the middle hollow cylinder 13 at the upper stage, so that the N middle hollow cylinders 13 are sequentially sleeved together to form a hollow cylinder; the top hollow cylinder 11 and the bottom hollow cylinder 15 are respectively positioned at two opposite ends of the cylinder, the top hollow cylinder 11 is sleeved on the inserting convex column 132 of the middle hollow cylinder 13 positioned at one end of the cylinder through the first sleeving connection groove 114, and the connecting convex column 152 of the bottom hollow cylinder 15 is inserted in the second sleeving connection groove 133 of the middle hollow cylinder 13 positioned at the other end of the cylinder; the first shaft hole 112, the second shaft holes 134 of the N middle hollow cylinders 13, and the third shaft hole 154 are sequentially communicated to form a hollow cavity 16 of the trunk 10; in the present embodiment, the first shaft hole 112, the second shaft hole 134 and the third shaft hole 154 have substantially the same diameter. The two adjacent second mounting grooves 135, the adjacent first mounting groove 116 and second mounting groove 135, and the adjacent third mounting groove 155 and second mounting groove 135 respectively enclose a mounting channel 17 for the branches 30 to be inserted, and the mounting channel 17 is communicated with the hollow cavity 16 of the trunk 10.

In this embodiment, enclose and all still be equipped with location arch 18 on the perisporium of second cover grafting groove 133 and first cover grafting groove 114, all concavely be equipped with constant head tank 19 on the periphery wall of grafting projection 132 and connection projection 152, location arch 18 can be with the cooperation of pegging graft of the constant head tank 19 that corresponds to opposite vertex hollow cylinder 11, middle hollow cylinder 13 and end hollow cylinder 15 location in trunk 10 assembling process, improvement assembly efficiency and precision.

In this embodiment, the annular hollow-out body 50 includes a plurality of sector ring tree crown areas 53 and sector ring side branch areas 54 connected between two adjacent sector ring tree crown areas 53, the radius of the sector ring tree crown areas 53 is greater than that of the sector ring side branch areas 54, the sector ring tree crown areas 53 and the sector ring side branch areas 54 are formed by spatially stacking and splicing octahedrons formed by connecting rods 51 in a three-dimensional array and boolean operation manner, each octahedron is formed by eight connecting rods 51 having an angle α ≧ 40 ° with a horizontal plane, an intersection of the connecting rods 51 is connected by a spherical node 55, wherein the spherical node 55 on the inner annular surface of the annular hollow-out body 50, that is, the spherical node 55 located on the innermost side of the annular hollow-out body 50, forms an assembly spherical node 56, the assembly spherical node 56 has an assembly hole 57, and one end of the branch 30 opposite to the main trunk 10 is inserted into the corresponding assembly hole 57.

In the present embodiment, the pore-forming template 100 is provided with N +1 sets of branches 30 corresponding to the installation channels 17, and the sets of branches 30 are arranged at intervals along the axial direction of the trunk 10; a plurality of branches 30 in each group of branches 30 are uniformly distributed at intervals around the circumference of the trunk 10, each branch 30 comprises a branch rod 32 and a plurality of first connecting rods 34, the plurality of first connecting rods 34 are arranged at equal angular intervals along the circumference of the trunk 10, the branch rod 32 comprises a plurality of V-shaped rods 321 sequentially connected along the circumference of the trunk 10 and a second connecting rod 323 with one end connected with the open end of the V-shaped rod 321, the tip of the V-shaped rod 321 is connected with one end of the first connecting rod 34, and the other end of the second connecting rod 323 is inserted into an assembling hole 57 of the assembling spherical node 56 so as to be connected with the annular hollow body 50 through the assembling hole 57 of the assembling spherical node 56; the other end of the first link 34 is inserted into the corresponding mounting channel 17.

In this embodiment, according to geometric characteristics such as the size, distribution position, number, and internal pore structure of the graphite rotor nozzle, the pore-forming template 100 for internal pore-forming of the graphite material is preferably constructed in an "axial tree" structure, in which: the central ventilation area in the graphite rotor (i.e. the main ventilation channel of the graphite rotor) is regarded as the trunk 10 of the "shaft tree" and is used for bearing the ventilation hinge function; the annular hollow body 50 of the 'axle tree' is regarded as the crown part of the 'axle tree', and the crown part bears the function of a terminal nozzle; the path from the trunk 10 to the crown is regarded as a branch 30 of an axis tree structure, and the branch 30 takes on the function of a ventilation branch. When in use, the gas flux (N)₂Or Ar, etc.) can be led from the main gas channel formed by the trunk 10 of the "tree" to any one of the end nozzles of the graphite rotor via the gas branch formed by the branches 30, forming a gas channel.

In this embodiment, the pore-forming template 100 is formed by using a 3D printing technology, which specifically includes the following steps:

step S11, determining the size parameter of the pore-forming template 100 according to the size parameter of the graphite rotor to be manufactured, specifically, the method includes the following steps:

determining the outline dimension of a graphite rotor blank: referring to fig. 1 and 2, the graphite rotor 200 generally includes a rotor body 210 and a plurality of impellers 230 uniformly spaced around the rotor body 210, so that the outer circumference of the graphite rotor 200 is concave-convex, and a plurality of terminal nozzles 250 are spaced around the outer circumference of the graphite rotor 200.

Let the diameter of the graphite rotor 200 be D₁And the total height of the graphite rotor 200 is H₁When the rotor blank 300 is manufactured, the corresponding machining allowance D 'of 5-10 mm is added on the surface of each outline of the graphite rotor 200, and the height allowance H' of 150-300 mm is reserved by considering the requirement of clamping. On the basis, the external dimension parameter diameter D of the rotor blank 300 is determined according to the expressions (1) and (2) respectively₂And height H₂(FIG. 3):

D₂＝D₁+D’＝D₁+5～10(mm) (1)

H₂＝H₁+H’＝H₁+150～300(mm) (2)

the position of the annular hollow-out body 50 area is determined by the parameters of the graphite rotor to be produced: for example, the outer diameter D1 and (0.6-0.75). D of the graphite rotor 200 may be set₁The size of the graphite rotor is that a circular ring is drawn for the diameter, the outline of the impeller of the graphite rotor 200 is intersected with the two drawn circular rings, and the area enclosed by the outline of the impeller of the graphite rotor 200 and the two circular rings is regarded as the area where the annular hollow-out body 50 is located;

the preferred graphite rotor nozzle aperture, the value range of connecting rod 51 external diameter promptly: the rotor nozzle aperture is an important functional parameter for constructing a pore wall structure in a graphite material, and under the condition that the number of nozzles in unit area is the same, the nozzle aperture is too large, so that the pore wall spacing is too small, the graphite material is loose in structure, and the oxidation resistance and the mechanical strength are poor; the small aperture of the nozzle can cause the difficult formation and poor rigidity of the shaft tree structure, and the graphite rotor is easy to be blocked in the using process, thereby leading to gas flux (N)₂Or Ar, etc.) cannot be efficiently transported. In order to facilitate the formation of the "tree-axis" structure and to fully utilize the performance of the rotor in purifying the aluminum melt, the nozzle aperture d is preferably selected according to the following formula (3)_nozzle：

d_nozzle＝0.2～0.8mm (3)

Determining the size parameter of the crown structure:

in the present embodiment, in order to avoid forming an overhanging structure, an octahedron is used as a basic unit to construct a tree crown structure, and the basic unit is composed of eight connecting rods 51 having an angle α of 40 ° to 55 ° (critical forming angle) with the horizontal plane, so as to avoid the problem that the tree crown structure fails to form a 3D technology due to the presence of the overhanging structure.

Connecting rod 51 diameter d of octahedral unit_cylinThe value range is determined by the formula (4):

d_cylin＝d_nozzle＝0.2～0.8mm (4)

at the junction of the connecting rods 51, a spherical node 55 is created as a secondary distribution hub to ensure the patency of each branch gas path. Diameter d of spherical node 55_sphere2-3 mm (fig. 12). In the area where the crown structure is located, through three dimensionsArray and boolean operations, the mathematical model of the crown structure can be generated by spatially stacking octahedral units (fig. 11).

In order to realize the assembly of the crown and the branches 30, an assembling spherical node 56 is designed at the inner side of the crown, and an assembling hole 57 is arranged at the lateral side of the assembling spherical node 56. Considering that a form and position error is generated when the laterally arranged assembly holes 57 are formed by using the 3D technology, and the form and position error is increased along with the increase of the number of the assembly holes 57, in order to ensure the realization of the function of the assembly holes 57, the aperture D of the assembly holes 57_assemDetermined by equation (5):

d_assem≈3·d_cylin+0.15mm (5)

determination of the size parameters of the branches 30:

in consideration of the gas distribution function of the branches 30 in the whole network system, the pore-forming template 100 includes a plurality of groups of branches 30 arranged at intervals along the axial direction of the trunk 10, and the outer diameters of the V-shaped rod 321 and the second connecting rod 323 are substantially the same, and the outer diameter of the first connecting rod 34 is larger than the outer diameters of the V-shaped rod 321 and the second connecting rod 323. For introducing a gas flux (N)₂Or Ar, etc.) are reasonably distributed from the branches 30 to the tail ends of the tree crowns, and simultaneously, the volume of the branches 30 is reduced to increase the requirement of tissue compactness of the corresponding area of the graphite rotor, and the diameter d of the first connecting rod 34_stemAnd length l_stemIs determined by equations (6) and (7), respectively:

d_stem＝(3.5～4.5)·d_cylin (6)

l_stem＝(0.2～0.3)·D₁ (7)

the assembly of the branch 30 with the crown is completed by inserting the branch rod 32 into the assembly hole 57. Similarly, to satisfy the rational distribution of gas, the V-shaped rod 321 and the second connecting rod 323 in the branch rod 32 have a diameter d_branchDetermined by equation (8):

d_branch＝(2～3)·d_cylin (8)

design of the dimensional parameters of the stem 10: the outer and inner diameters of the stem 10 can be designed as required, which is known in the art and will not be described herein for brevity.

The volume ratio of the pores inside the graphite rotor blank 300 is preferably:

under the condition of the same nozzle aperture, the larger the pore volume of the graphite rotor is, the more the number of the nozzles is, the more bubbles are generated, and the purification effect of the aluminum melt is improved. However, the excessive pore volume ratio causes the loose structure, resulting in the decrease of oxidation resistance and mechanical properties of the graphite rotor made of the graphite material. In order to meet the requirements of the number of nozzles of the graphite rotor, oxidation resistance and mechanical property, the ratio of pore volume is preferably 0.02-0.05.

Verifying the volume ratio of the inner pores of the graphite rotor blank:

the volume V of the rotor blank was calculated from the following equations (9), (10) and (11), respectively₁Volume V of 'axial tree' template_modelAnd the volume ratio phi of the inner pores of the rotor blank, wherein the volumes of the trunk 10, the annular hollow body 50 and the branches 30 are respectively V_trunk、V_hollowAnd V_branchRepresents:

V₁＝π·D₂ ²·H₂/4 (9)

V_model＝(0.75～0.8)·V_trunk+V_hollow+V_branch (10)

Φ＝V_model/V₁ (11)

in the formula, V_trunkIs the trunk volume, V_hollowVolume of annular hollow-out body, V_branchFor limb volume (the pore-forming template 100 of this embodiment is modeled in 3D, so V_trunk、V_hollowAnd V_branchThe values of (d) can be obtained directly in software). If the value of phi is not in the interval of 0.02,0.05]In the specification, the size of the pore-forming template 100 is modified and designed until the value of the pore volume ratio phi is within the interval [0.02,0.05 ]]In (1).

Step S12, determination of the material quality of the pore-forming template 100:

in order to meet the requirements of rigidity of the 'axle tree' structure and convenience in removal (acid etching), the annular hollow-out bodies 50 and the branches 30 are made of metal powder. In the case of a cylindrical graphite material, as the branches 30 converge toward the central region of the trunk 10, the proportion of the metal branches 30 per unit volume increases, which causes a rapid increase in thermal stress between the metal branches 30 and the graphite material body, and further causes cracks in the graphite material, resulting in the graphite material being discarded. In order to eliminate the stress concentration in the central region of the graphite material, photosensitive resin C-UV 9400 is preferred as the material of the molding trunk 10, the principle of which is:

(1) in the roasting process of the graphite material, along with the removal of organic components such as asphalt and the like by dehydration, graphite particles shrink and are tightly attached to the outer walls of the metal annular hollow bodies 50 and the metal branches 30, so that hole walls are formed inside the graphite material. Meanwhile, the material of the photosensitive resin C-UV 9400 is pyrolyzed and carbonized, that is, in the process of heating the trunk 10 made of the photosensitive resin C-UV 9400, the photosensitive resin material is softened, decomposed, dehydrated and volatilized until the carbide remains, and the great mass is lost due to the decomposition, dehydration and volatilization, so that the volume V of the trunk 10_trunkThe temperature is sharply reduced to be below 20-25%, a cavity is formed in the graphite material, and the cavity provides a free extending space for the metal annular hollow-out body 50 and the metal branches 30 which expand when heated, so that most of thermal stress is eliminated, and the integrity of the graphite material after roasting is ensured; in addition, in the baking process, the photosensitive resin C-UV 9400 can be discharged along the pore channels formed by the volatilization of the asphalt, so that the volatilization process of the trunk 10 can be smoothly carried out.

(2) In the high-temperature graphitization (temperature ≧ 3073K), as the temperature rises and exceeds the melting point of the metal, the metal annular hollow-out body 50 and the metal branches 30 are liquefied, and the metal melt flows into the cavity formed by pyrolysis and carbonization of the trunk 10. During the furnace cooling period, the metal annular hollow-out body 50 and the metal branches 30 are solidified along with the temperature reduction. Due to the change of the shapes of the annular hollowed-out bodies 50 and the branches 30, the annular hollowed-out bodies 50 and the branches 30 are separated from contact with the graphite material at the hole walls. In addition, the trunk 10 is a hollow cylinder, and in the high-temperature roasting and graphitization process, the internal stress field of the trunk 10 is uniformly distributed, so that the uncontrollable preparation process caused by overlarge residual stress in the blank is prevented.

Step S13, preparing the annular hollow-out body 50 and the branches 30 by 3D printing, which specifically includes the following steps:

step a, metal powder pretreatment: and (2) loading metal powder with the particle size of 15-53 mu m by using a ceramic utensil, then putting the ceramic utensil into a vacuum oven, heating to 373K, preserving the heat for 2h, taking out the dried metal powder, and screening by using a 200-280-mesh screen for later use.

Step b, preparing metal 3D printing: forming the annular hollowed-out body 50 and the branches 30 by adopting powder bed laser melting (SLM) metal 3D printing equipment, specifically, sand blasting a titanium alloy substrate material, and then installing the titanium alloy substrate material into a forming cylinder; then, the forming cylinder descends one layer thickness (30-60 mu m), and the powder supply cylinder correspondingly ascends one layer thickness; the powder of the powder supply cylinder is scraped into the forming cylinder by a scraper, a layer of metal powder is uniformly laid on the surface of the titanium alloy substrate, and the redundant powder is scraped into a recovery cylinder; and then, preheating the titanium alloy substrate to 330-350K, introducing high-purity Ar gas into the forming chamber, and simultaneously controlling the oxygen content in the forming chamber to be lower than 0.1%.

Step c, determining metal 3D forming parameters of the annular hollow-out body 50 and the branches 30:

and (3) introducing the three-dimensional models of the annular hollow bodies 50 and the branches 30 into special data processing software to perform slicing, path planning and printing parameter processing, and manufacturing a processable data project. For the fine characteristics of the annular hollow-out body 50 and the branches 30, the preferable process parameters are as follows: the laser scanning power is 200-300W; the diameter of the light spot is 80-100 mu m; the scanning speed is 800-1500 mm/s; the scanning distance is 100 μm; the thickness of the layer is 30-60 mu m;

step D, forming the annular hollow-out body 50 and the branches 30 by metal 3D:

and clicking a start button to start printing after the parameters of the 3D printing equipment, such as oxygen content, substrate temperature, inert gas and the like, reach set conditions. Under the control of the scanning galvanometer, the laser beam rapidly scans the metal powder according to the cross-sectional shapes of the current layers of the annular hollow-out body 50 and the branches 30, so that the metal powder is melted → solidified to form a cladding layer. With the scanning of the current layers of the annular hollow-out body 50 and the branches 30 completed, the titanium alloy substrate descends by one layer thickness, and the powder supply cylinder correspondingly ascends by one layer thickness. And (3) paving a layer of metal powder on the substrate again by using a scraper, then scanning the next layer of the annular hollow-out body 50 and the branch 30, and repeating the process until the annular hollow-out body 50 and the branch 30 are formed.

Step e, post-treatment of the annular hollow bodies 50 and the branches 30

And (3) placing the formed annular hollow-out body 50 and the branches 30 into a vacuum furnace, heating to a temperature of 923-1123K, and preserving heat for 2-4 hours to eliminate internal stress. And after furnace air cooling, taking out, and cutting and separating the annular hollow bodies 50 and the branches 30 from the titanium alloy substrate.

Step S13, preparing the trunk 10 by 3D printing, which specifically includes the steps of:

step S131, determining the light curing molding parameters of the trunk 10:

converting a three-dimensional model of the backbone 10 into a file in an STL format for exporting, then adopting specific slicing software to slice the model of the STL file to obtain data of a cross section layer of the backbone 10, then importing the data into an SLA photocuring printer system, designing a scanning path by the system, and accurately controlling the movement tracks of a laser scanner and a lifting platform. For the geometrical characteristics of the stem 10, the preferred process parameters are: the profile scanning speed is 8000 mm/s; the filling scanning speed is 2000 mm/s; the supporting scanning speed is 2000 mm/s; jump across speed 30000 mm/s; the feeding speed of the workbench is 5 mm/s.

Step S132, light-curing the molded trunk 10

Projecting a laser beam into the liquid photosensitive resin according to a designed scanning path through a scanner, and solidifying the resin in a specific area to form a cross-section layer of the trunk 10; subsequently, the lifting platform is lowered by one section layer thickness, the resin is made to flow and cover on the cured layer, and then the next section layer of the trunk 10 is cured by the laser; the above process is repeated until the entities of the backbone 10 are formed by stacking layer upon layer.

Step S14, assembling heterogeneous material coupled 'axle tree' template

The metal branch 30, the metal annular hollow-out body 50 and the photosensitive resin main body 10 are assembled to obtain the heterogeneous material coupled 'tree axis' pore-forming template 100.

Step S2, isostatic pressing a rotor blank: and (3) putting the coke powder and the pore-forming template 100 into a mold sheath, and performing isostatic pressing to obtain a rotor blank.

In step S2, proper design of the mold jacket is a key factor in ensuring that a rotor blank of accurate size and shape is obtained. In the molding process, the mold sheath transmits pressure to the graphite powder filled in the mold sheath, and the volume of the graphite powder shrinks after the graphite powder is pressed. In order to ensure that the size of the rotor blank meets the requirement after isostatic pressing, the inner diameter D of the die sleeve₃And height H₃Are determined by equations (12) and (13), respectively:

D₃＝(1.25～1.5)·D₂ (12)

H₃＝(1.25～1.5)·H₂ (13)

in this embodiment, before the step of isostatic pressing the rotor blank, the method further comprises the step of pretreating the coke powder: crushing and grinding the coke powder by using a Raymond mill to obtain the coke powder with the particle size of 5-12 mu m; selecting asphalt as a bonding agent, mixing the asphalt and coke powder according to a preset ratio, and uniformly mixing the mixed powder. In order to reduce waste products of green bodies, the asphalt and the coke powder are preferably mixed according to the mass ratio of 2: 8-3: 7. In order to reduce the influence of the organic components in the asphalt on the yield of the graphite composite material due to thermal decomposition and volatilization, the kneading machine is adopted to fully and uniformly mix the prepared powder, and the key process parameters such as the temperature, the kneading time and the like in the kneading process are determined. The method comprises the following specific steps: putting the mixed powder of the asphalt and the coke powder into a kneader, heating to the temperature of 433-513K, and mixing for 40-80 min; taking out the mixed materials, rolling the mixed materials into a sheet with the thickness of 1-3 mm by using a roller press, and repeatedly rolling for 2-4 times; and after the thin slices are dried in the air, crushing the thin slices into mixed materials with the particle size of 5-12 microns by using a Raymond mill again for later use.

The method comprises the following steps of (1) putting coke powder and a pore-forming template 100 into a mold sheath, and specifically comprises the following steps: filling a proper amount of mixed materials into a mold sheath according to the spatial position relation between a graphite rotor nozzle and a rotor blank; then, flattening the mixed material through mechanical compaction; then, the pore-forming template 100 is placed in the mold sheath and aligned and centered. Then, the mixed material is filled into the mold sheath, and the pore-forming template 100 is uniformly covered until the mold sheath is filled. Subsequently, the mold capsule is sealed and mechanically tapped again.

The isostatic compaction rotor blank comprises the following steps:

firstly, carrying out vacuum-pumping degassing treatment on a mold sheath filled with coke powder and a pore-forming template 100, wherein the vacuum degree is less than or equal to 0.75MPa, so as to overcome the soft state of the mold sheath after charging;

and secondly, placing the die sheath into a high-pressure cylinder, and in order to take account of smooth escape of gas in the mixed powder and avoid the condition that cracks appear on the surface of the die sheath due to unbalanced stress in the blank forming process, preferably applying isostatic pressure to the die sheath at a rate of 1-3 MPa/s to 150-300 MPa, and maintaining the pressure for 10-30 min to ensure compact tissue of the blank and avoid the phenomena of layering, breaking and the like in the tissue.

And then, in order to further control the blank quality and avoid the blank from cracking and layering caused by elastic recovery of a die sheath, reducing the pressure at the rate of 1-3 MPa/s to reduce the pressure to normal pressure, and then demoulding to obtain the rotor blank.

Step S3, baking: and (3) putting the rotor blank into a roasting furnace for sintering to convert the rotor blank into a carbonized composite material, and discharging organic volatile matters contained in the rotor blank in the sintering and curing process.

In step S3, the rotor blank is placed in a firing furnace for sintering. In order to ensure that the mixed material is fully sintered and cured, a hole wall is formed at an interface part contacted with the metal template, and organic volatile matters in the curing process are fully discharged; meanwhile, the problem that the temperature inside and outside the rotor blank is uneven to cause the blank to have cracks due to the fact that the temperature rising rate is too high is avoided; the preferred sintering process is specifically as follows: firstly, heating to 373-423K from room temperature at a heating rate of 5-15K/min, and keeping the temperature for 0.5-1 h to promote the asphalt to be fully volatilized; then, heating to 573-633K at a heating rate of 5-10K/min, and preserving the heat for 1-1.5 hours to promote the organic components of the asphalt to be fully decomposed; then, heating to 923 to 1023K at the heating rate of 1 to 3K/h, and preserving heat for 2 to 5 h; then, heating to 1123-1278K at the heating rate of 2-5K/h, and preserving heat for 192-240 h to promote full carbonization of the asphalt;

and finally, in order to avoid the cracking of the blank caused by the uneven temperature inside and outside the blank due to the excessively high cooling rate, the blank is cooled at a rate of preferably less than or equal to 50K/h until the temperature is reduced to the room temperature, and the roasting treatment of the blank is considered to be finished. At this point, the rotor blank is converted into a carbonized composite material.

Step S4, graphitizing and sintering: and (3) putting the carbonized composite material into a graphitization furnace for graphitization sintering, so that the carbonized composite material is converted into a graphite composite material. In the sintering process, in order to avoid cracks of the composite material caused by nonuniform internal and external temperatures of the carbonized composite material due to excessively high temperature rise rate, the preferred graphitization sintering process is as follows: heating from room temperature to 1473-1773K at a heating rate of 5-15K/min, and keeping the temperature for 30-60 min. Then, heating to 2473-3073K at the heating rate of 2-5K/min, and preserving heat for 60-120 min; and finally, in order to avoid cracks of the composite material caused by uneven temperature inside and outside the composite material due to excessively high cooling rate, the composite material is cooled at a rate of preferably less than or equal to 50K/h until the temperature is reduced to room temperature, and the graphitization treatment process of the carbonized composite material is considered to be finished. At this time, the carbonized composite material is converted into a graphite composite material.

Step S5, X-ray observation of internal structure of graphite composite material

And (3) carrying out three-dimensional observation on the internal organization of the graphite composite material by adopting an X-ray machine, and accurately marking the position of the metal annular hollow-out body 50 in the graphite composite material.

Step S6, machining the graphite composite material

According to the position mark of the metal annular hollow-out body 50, the graphite composite material taken out from the graphitization furnace is processed by turning and the like until the outer side part of the metal annular hollow-out body 50 is exposed, and the graphite composite material is in the shape of a rotor blank as shown in fig. 3.

Step S7, removing the metal template: the graphite composite material is immersed in the corrosive liquid to remove the annular hollow-out bodies 50 made of the metal material and the branches 30 made of the metal material, so that the ordered array macroporous structure is obtained in the graphite composite material. In step S7, an acidic etchant may be disposed according to the characteristics of the metal material. Then, the graphite composite material is immersed in an acidic corrosive liquid, and the metal annular hollow-out bodies 50 and the metal branches 30 are removed in an acid pickling corrosion mode, so that an ordered array macroporous structure is obtained in the graphite composite material. And after the corrosion is finished, washing the graphite composite material with clear water.

In the production process of the graphite rotor, cracks are easily generated in the material and are scrapped due to the problem of internal stress in the isostatic compaction, roasting and graphitization processes, and the production yield of the graphite rotor is low and the efficiency is low due to the long production period of the graphite rotor, usually 2-3 months. In the embodiment, an organic material is used as a material for forming the trunk, and the trunk is in a hollow cylinder structure, so that in the roasting and graphitizing processes, the thermal stress in the preparation process of the graphite composite material can be eliminated, and the trunk 10 in the hollow cylinder structure provides a moving space for the movement of the branches 30 due to the compression in the isostatic pressing process, so that the graphite composite material can be further prevented from cracking, and the yield of finished products is improved. In addition, the parameters of the roasting, graphitization and isostatic pressing processes are optimized, the problems of cracking and the like of the material in the roasting, graphitization and isostatic pressing processes are further prevented, and the product yield is improved.

The following will further explain the controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining according to the present invention with reference to the specific embodiment.

Example 1

The embodiment 1 of the invention provides a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining, which comprises the following steps:

step S1, providing the pore-forming template 100, where the pore-forming template 100 is formed and manufactured by a 3D printing technique, and the method may specifically include the following steps:

determining the outline dimension of a graphite rotor blank according to the final dimension parameters of the graphite rotor: in particular, according to the graphite rotor diameter D₁And the total height H of the graphite rotor₁And (fig. 2), adding corresponding machining allowance D 'and height allowance H' on each outline surface of the graphite rotor. On the basis, the external dimension parameter diameter D of the rotor blank is determined according to the formulas (1) and (2) respectively₂And height H₂(FIG. 3): in this example, D is taken₂＝D₁+5mm，H₂＝H₁+150mm。

The position of the annular hollow-out body 50 area is determined by the parameters of the graphite rotor to be produced: in this embodiment, the outer diameters D1 and 0.6. D of the graphite rotor to be prepared are used₁The size of the graphite rotor is that a circle is drawn for the diameter, the outline of the impeller of the graphite rotor is intersected with the two drawn circles, and the formed area is regarded as the area where the annular hollow-out body 50 is located;

the preferred graphite rotor nozzle aperture, that is, the value range of the outer diameter of the connecting rod 51: in order to facilitate the formation of the 'axle tree' structure and fully exert the performance of the rotor for purifying the aluminum melt, the aperture d of the nozzle is preferably selected according to the formula (3)_nozzleIn this embodiment, take d_nozzle＝0.2mm。

Determining the size parameter of the crown structure: the tree crown structure is constructed by using an octahedron as a basic unit, the basic unit consists of eight connecting rods 51 forming an angle alpha of 40 degrees (critical forming angle) with the horizontal plane, and the diameter d of each connecting rod 51 of the octahedron unit_cylinThe value range is determined by the formula (4), and d is taken in the embodiment_cylin＝d_nozzle＝0.2mm。

The diameter of the spherical node 55 in this embodiment is taken as d_sphere2 mm. In the sector area where the crown structure is located, octahedral units are spatially stacked in a three-dimensional array and boolean operation manner, so that a crown structure mathematical model can be generated, as shown in fig. 11. Diameter d of the fitting hole 57_assemRepresented by the formula (5) d_assem≈3·d_cylin+0.15 mm.

Determination of the size parameters of the branches 30: in the present embodiment, the diameter d of the first link 34 of the limb 30_stemAnd length l_stemIs determined by the following equations (6) and (7), respectively, and d is taken in this example_stem＝3.5·d_cylin，l_stem＝0.2·D₁. Diameter d of V-shaped rod 231 and second connecting rod 322 in branch rod 32_branchDetermined by equation (8), this example takes d_branch＝2·d_cylin。

Preferably, the pore volume ratio is 0.02-0.05, and verifying the volume ratio of the pores in the graphite rotor blank: calculating the volume V of the graphite rotor blank by the formulas (9), (10) and (11)₁Volume V of 'axial tree' template_modelAnd the volume ratio phi of the inner pores of the rotor blank, if the numerical value of phi is not in the interval of [0.02,0.05 ]]In the above-mentioned method, the size of pore-forming template 100 is modified until the pore volume ratio phi value is in the interval of 0.02,0.05]In (1).

Step S12, determination of the material quality of the pore-forming template 100: in the present embodiment, the annular hollow-out body 50 and the branches 30 are made of TC4, and the photosensitive resin C-UV 9400 is used as the material for forming the trunk 10.

step a, metal powder pretreatment: and (3) loading metal powder with the particle size of 15 microns by using a ceramic vessel, then putting the ceramic vessel into a vacuum oven, heating to 373K, preserving heat for 2 hours, taking out the dried metal powder, and screening by using a 200-mesh screen for later use.

Step b, preparing for metal 3D printing: forming the annular hollowed-out body 50 and the branches 30 by adopting powder bed laser melting (SLM) metal 3D printing equipment, specifically, performing sand blasting treatment on a titanium alloy substrate material, and then installing the titanium alloy substrate material into a forming cylinder; then, the forming cylinder descends one layer thickness (30 mu m), and the powder supply cylinder correspondingly ascends one layer thickness; the powder of the powder supply cylinder is scraped into the forming cylinder by a scraper, a layer of metal powder is uniformly laid on the surface of the substrate, and the redundant powder is scraped into a recovery cylinder; subsequently, the substrate was preheated to 330K, and high purity Ar gas was introduced into the molding chamber while controlling the oxygen content in the molding chamber to be less than 0.1%.

Step c, determining metal 3D forming parameters of the annular hollow-out body 50 and the branches 30: and (3) introducing the three-dimensional models of the annular hollow bodies 50 and the branches 30 into special data processing software to perform slicing, path planning and printing parameter processing, and manufacturing a processable data project. For the fine features of the annular hollow-out body 50 and the branches 30, the preferred process parameters are as follows: laser scanning power is 200W; the diameter of the light spot is 80 μm; the scanning speed is 800 mm/s; the scanning distance is 100 μm; the layer thickness is 30 μm;

step D, forming the annular hollow-out body 50 and the branches 30 by metal 3D: and clicking a start button to start printing after the parameters of the 3D printing equipment, such as oxygen content, substrate temperature, inert gas and the like, reach set conditions. Under the control of the scanning galvanometer, the laser beam rapidly scans TC4 powder according to the current layer cross-sectional shapes of the annular hollow-out body 50 and the branches 30, so that the TC4 powder is melted → solidified to form a cladding layer. Along with the completion of scanning of the current layers of the annular hollow-out body 50 and the branches 30, the titanium alloy substrate descends by one layer thickness, and the powder supply cylinder correspondingly ascends by one layer thickness. And (3) paving a layer of TC4 powder on the titanium alloy substrate again by using a scraper, then scanning the next layer of the annular hollow body 50 and the branch 30, and repeating the process until the annular hollow body 50 and the branch 30 are molded.

Step e, post-processing the annular hollow-out body 50 and the branches 30: and (3) placing the formed annular hollow-out body 50 and the branches 30 into a vacuum furnace, heating to 923K, and preserving heat for 2 hours to eliminate internal stress. After furnace air cooling, the hollow-out body 50 and the branches 30 were taken out and separated from the titanium alloy substrate by cutting, and the obtained sample was as shown in fig. 16 and 17.

step S131, determining the light curing molding parameters of the stem 10: converting a three-dimensional model of the backbone 10 into a file in an STL format for exporting, then adopting specific slicing software to slice the model of the STL file to obtain data of a cross section layer of the backbone 10, then importing the data into an SLA photocuring printer system, designing a scanning path by the system, and accurately controlling the movement tracks of a laser scanner and a lifting platform. For the geometrical characteristics of the stem 10, the preferred process parameters are: the profile scanning speed is 8000 mm/s; the filling scanning speed is 2000 mm/s; the supporting scanning speed is 2000 mm/s; jump across speed 30000 mm/s; the feeding speed of the workbench is 5 mm/s.

Step S132, light-curing the molded stem 10: projecting a laser beam into the liquid photosensitive resin according to a designed scanning path through a scanner, and solidifying the resin in a specific area to form a cross-section layer of the trunk 10; subsequently, the lifting platform is lowered by one section layer thickness, the resin is made to flow and cover on the cured layer, and then the next section layer of the trunk 10 is cured by the laser; the above process is repeated until the entities of the backbone 10 are formed by stacking layer upon layer (fig. 18).

Step S14, assembling the heterogeneous material coupled "axial tree" template: the metal branches 30, the metal annular hollow-out bodies 50, and the photosensitive resin trunk 10 are assembled in sequence to obtain a "tree-axis" pore-forming template 100 (fig. 19).

Step S2, isostatic pressing a rotor blank: and (3) putting the coke powder and the pore-forming template 100 into a mold sheath, and performing isostatic pressing to obtain a rotor blank. Inner diameter D of die sleeve₃And height H₃Are respectively represented by the formula (12) D₃＝(1.25～1.5)·D₂And (13) H₃＝(1.25～1.5)·H₂To determine, this example takes D₃＝1.25·D₂，H₃＝1.25·H₂。

In this embodiment, before the step of isostatic pressing the rotor blank, the method further comprises the step of pretreating the coke powder: crushing and grinding the coke powder by using a Raymond mill to obtain the coke powder with the granularity of 5 mu m; selecting asphalt as a binder, mixing the asphalt and coke powder according to a mass ratio of 2:8, and fully and uniformly mixing the mixed powder by adopting a kneader, wherein the specific ratio is as follows: heating the mixed powder of the asphalt and the coke powder in a kneader to 433K, and mixing for 40 min; taking out the mixed materials, rolling the mixed materials into a sheet with the thickness of 1mm by using a roller press, and repeatedly rolling for 2 times; after the thin slices are dried in the air, the thin slices are crushed and ground into mixed materials with the grain diameter of about 5 microns by a Raymond mill for later use. And putting the coke powder and the pore-forming template 100 into a mold sheath.

The isostatic compaction rotor blank comprises the following steps: firstly, carrying out vacuum-pumping degassing treatment on a mold sheath filled with coke powder and a pore-forming template 100, wherein the vacuum degree is less than or equal to 0.75MPa (0.6 MPa in the embodiment); and secondly, placing the die sheath into a high-pressure cylinder, applying isostatic pressure to the die sheath at a rate of 1MPa/s to 150MPa, and maintaining the pressure for 10min in order to take account of smooth escape of gas in the mixed powder and avoid the condition that cracks appear on the surface due to unbalanced stress in the blank forming process. Then, the pressure was reduced at a rate of 1MPa/s to atmospheric pressure, followed by mold release to obtain a rotor blank (FIG. 20).

Step S3, baking treatment: and (3) putting the rotor blank into a roasting furnace for sintering to convert the rotor blank into a carbonized composite material, and discharging organic volatile matters contained in the rotor blank in the sintering and curing process. The sintering process in this example is specifically as follows: firstly, heating to 373K from room temperature at a heating rate of 5K/min, and keeping the temperature for 0.5h to promote the volatilization of asphalt; then, heating to 573K at the heating rate of 5K/min, and preserving heat for 1h to promote the decomposition of the organic components of the asphalt; then, heating to 923K at the heating rate of 1K/h, and keeping the temperature for 2 h; then, heating to 1123K at the heating rate of 2K/h, and preserving heat for 192h to promote full carbonization of the asphalt; finally, the temperature is preferably reduced at a rate of ≦ 50K/h (40K/h in this example) until the temperature is reduced to room temperature, which is considered to be the end of the calcination treatment of the blank. At this point, the rotor blank is converted into a carbonized composite material (fig. 21).

Step S4, graphitizing and sintering: and (3) putting the carbonized composite material into an Acheson graphitizing furnace for graphitizing and sintering to convert the carbonized composite material into a graphite composite material. The graphitization sintering process comprises the following steps: heating from room temperature to 1473K at the heating rate of 5K/min, and keeping the temperature for 30 min. Then, heating to 2473K at the heating rate of 2K/min, and preserving the heat for 60 min; finally, preferably reducing the temperature at a rate of ≦ 50K/h (40K/h is adopted in the embodiment) until the temperature is reduced to room temperature, and determining that the graphitization treatment process of the carbonized composite material is finished. At the moment, the carbonized composite material is converted into the graphite composite material, as shown in fig. 22, fig. 22 is an interface topography of the graphite/Ti-based pore-forming template, and the interface bonding is good without micro cracks, which indicates that the roasting and graphitizing process parameters are reasonably selected, and lays a foundation for obtaining good graphite composite materials. In addition, the metal template part of the pore-forming template is removed by subsequent acid etching, so that a required macroporous structure can be formed in the graphite.

Step S5, X-ray observation of the internal structure of the graphite composite material: the internal structure of the graphite composite material is observed three-dimensionally by using an X-ray machine, as shown in fig. 23, in the embodiment, the longitudinal section and the trunk cross-sectional position of the rotor blank graphitized by using the X-ray machine and the positions of the pore-forming template branches 30 and the annular hollow bodies 50 are observed by using X-rays, and the result shows that the obtained picture has no color lines, which indicates that the graphitized rotor blank has no micro-cracks inside, and the structure of the pore-forming template 100 can be observed, and the position of the metal annular hollow bodies 50 in the graphite composite material is identified according to the observation result of X-ray observation.

Step S6, machining the graphite composite material: and processing the graphite composite material according to the position mark of the metal annular hollow-out body 50 until the outer side part of the metal annular hollow-out body 50 is exposed.

Step S7, removing the metal template: the graphite composite material is soaked in an acidic corrosive liquid, and the annular hollow-out bodies 50 and the branches 30 of the metal material are removed in an acid pickling corrosion mode, so that an ordered array of macroporous structure is obtained in the graphite composite material. And after the corrosion is finished, washing the graphite composite material with clear water. In the present embodiment, an acidic etching solution in which hydrofluoric acid, nitric acid, and water are mixed is disposed in accordance with the characteristics of the material TC 4. Wherein, the molar ratio of hydrofluoric acid, nitric acid and water in the acidic corrosive liquid is as follows: HF: HNO₃:H₂O＝1:3:7 (14)

Then, the internal structure of the graphite composite material can be observed in a three-dimensional mode by the aid of the X-ray machine again, so that the annular hollow-out body 50 made of the metal material and the branches 30 made of the metal material are completely removed, and the ordered macroporous (less than or equal to 1mm) graphite composite material required by development of a novel graphite rotor is obtained.

Example 2

The embodiment 2 of the invention provides a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining, which comprises the following steps:

step S1, providing a pore-forming template 100: the pore creating template 100 has the same structure as that of embodiment 1, and will not be described herein for brevity. The pore-forming template 100 is formed by a 3D printing technology, and may specifically include the following steps:

determining the outline dimension of a graphite rotor blank according to the final dimension parameters of the graphite rotor: according to the diameter D of the graphite rotor₁And the total height H of the graphite rotor₁And (2) adding a corresponding machining allowance D 'of 8mm and a reserved height allowance H' of 200mm on each contour surface of the graphite rotor, and determining the contour dimension parameter diameter D of the rotor blank according to the formulas (1) and (2) respectively on the basis of the machining allowance D 'of 8mm and the reserved height allowance H' of 200mm₂And height H₂(FIG. 3): that is, in this embodiment, take D₂＝D₁+8mm，H₂＝H₁+200mm。

Determining the position of the annular hollowed-out body 50 area according to the parameters of the graphite rotor to be prepared: the outer diameters D1 and 0.7. D of the graphite rotor₁The size of the graphite rotor is that a circular ring is drawn for the diameter, the outline of the impeller of the graphite rotor is intersected with the two drawn circular rings, and the intersected area is regarded as the area where the annular hollow-out body 50 is located;

preference is given to the nozzle bore diameter d according to formula (3)_nozzleIn this example, take d_nozzle＝0.5mm。

Determining the size parameter of the crown structure: the tree crown structure is constructed by using an octahedron as a basic unit, the basic unit is composed of eight connecting rods 51 with an included angle alpha of 50 degrees (critical forming angle) with the horizontal plane, and the diameter d of the connecting rod 51 of the octahedron unit in the embodiment is the diameter d_cylin0.5 mm; diameter d of the ball node 55_sphere2.5 mm. And (3) piling the octahedral units in space at the area position of the crown structure in a three-dimensional array and Boolean operation mode to generate the crown structure mathematical model. In order to realize the assembly of the crown and the branch 30, a spherical node 56 is designed and assembled on the inner side of the crown. The fitting spherical node 56 is provided with a fitting hole 57 in the lateral direction, and the aperture d of the fitting hole 57_assemRepresented by the formula (5) d_assem≈3·d_cylin+0.15 mm.

Determination of the size parameters of the branches 30: diameter d of first link 34 in limb 30_stemAnd length l_stemIs determined by the following equations (6) and (7), respectively, and d is taken in this example_stem＝4·d_cylin，l_stem＝0.25·D₁. Diameter d of V-shaped rod 231 and second connecting rod 322 in branch rod 32_branchRepresented by the formula (8) d_branch＝(2～3)·d_cylinTo determine, this embodiment takes d_branch＝2.5·d_cylin。

The volume ratio of the internal pores of the graphite rotor blank is preferably as follows: preferably, the ratio of the pore volume is 0.02-0.05.

Verifying the volume ratio of the inner pores of the graphite rotor blank: calculating the volume V of the graphite rotor blank by the formulas (9), (10) and (11)₁Volume V of 'axial tree' template_modelAnd the volume ratio phi of the inner pores of the graphite rotor blank, if the numerical value of phi is not in the interval of 0.02,0.05]In the specification, the size of the pore-forming template 100 is modified and designed until the value of the pore volume ratio phi is within the interval [0.02,0.05 ]]In (1).

in order to meet the requirements of rigidity of the 'arbor tree' structure and convenience in (acid etching) removal, the annular hollow-out body 50 and the branches 30 are both prepared from powder made of 18Ni300 materials. Photosensitive resin C-UV 9400 is preferred as the material of the molded trunk 10.

step a, metal powder pretreatment: loading 18Ni300 powder with the particle size of 35 mu m by using a ceramic ware, then putting the ceramic ware into a vacuum oven, heating to 373K, preserving heat for 2h, taking out the dried 18Ni300 powder, and screening by using a 250-mesh screen for later use.

Step b, preparing metal 3D printing: forming the annular hollowed-out body 50 and the branches 30 by adopting powder bed laser melting (SLM) metal 3D printing equipment, specifically, sand blasting a titanium alloy substrate material, and then installing the titanium alloy substrate material into a forming cylinder; then, the forming cylinder descends one layer thickness (50 μm), and the powder supply cylinder correspondingly ascends one layer thickness; the powder of the powder supply cylinder is scraped into the forming cylinder by a scraper, a layer of 18Ni300 powder is uniformly spread on the surface of the substrate, and the redundant powder is scraped into a recovery cylinder; and then, preheating the titanium alloy substrate to 340K, introducing high-purity Ar gas into the forming chamber, and simultaneously controlling the oxygen content in the forming chamber to be lower than 0.1%.

and (3) importing the three-dimensional models of the annular hollow bodies 50 and the branches 30 into special data processing software to perform slicing, path planning and printing parameter processing, and manufacturing a processable data project. For the fine characteristics of the annular hollow-out body 50 and the branches 30, the preferable process parameters are as follows: laser scanning power 250W; the diameter of the light spot is 90 mu m; the scanning speed is 1000 mm/s; the scanning distance is 100 μm; the layer thickness is 50 μm;

and D, forming the annular hollow-out body 50 and the branches 30 in a metal 3D mode, wherein the steps are the same as those in the embodiment 1, and the details are omitted for the sake of brevity.

Step e, post-processing the annular hollow-out body 50 and the branches 30: and (3) putting the annular hollow-out body 50 and the branches 30 obtained by molding into a vacuum furnace, heating to 1023K, and preserving heat for 3h to eliminate internal stress. And after furnace air cooling, taking out, and cutting and separating the annular hollow bodies 50 and the branches 30 from the titanium alloy substrate.

step S131, determining the light curing molding parameters of the stem 10: converting the three-dimensional model of the backbone 10 into a file in an STL format for export, then adopting specific slicing software to slice the model of the STL file to obtain data of a cross section layer of the backbone 10, then importing the data into an SLA photocuring printer system, designing a scanning path by the system, and accurately controlling the motion tracks of a laser scanner and a lifting platform. For the geometrical characteristics of the stem 10, the preferred process parameters are: the profile scanning speed is 8000 mm/s; the filling scanning speed is 2000 mm/s; the supporting scanning speed is 2000 mm/s; jump speed 30000 mm/s; the feeding speed of the working table is 5 mm/s.

Step S132, light-curing the molded stem 10: projecting laser beams into liquid photosensitive resin according to a designed scanning path through a scanner, and solidifying the resin in a specific area to form a section layer of the trunk 10; subsequently, the lifting platform is lowered by one cross-section layer thickness, the resin is made to flow and cover the solidified layer, and then the next cross-section layer of the trunk 10 is solidified by the laser; the above process is repeated until the entities of the backbone 10 are formed by stacking layer upon layer.

Step S14, assembling the heterogeneous material coupled "axial tree" template: the metal branch 30, the metal annular hollow-out body 50 and the photosensitive resin main body 10 are assembled in sequence, and the heterogeneous material coupled 'tree axis' pore-forming template 100 structure can be obtained.

Step S2, isostatic pressing a rotor blank: and (3) putting the coke powder and the pore-forming template 100 into a mold sheath, and performing isostatic pressing to obtain a rotor blank. In order to ensure that the size of the graphite rotor blank after isostatic pressing meets the requirement, the inner diameter D of the die sleeve₃And height H₃Are determined by equations (12) and (13), respectively: in this example, D is taken₃＝1.35D₂，H₃＝1.35H₂。

In the embodiment, before the step of isostatic pressing the rotor blank, the method further comprises the step of pretreating the coke powder: crushing and grinding the coke powder by a Raymond mill to obtain the coke powder with the particle size of 10 mu m; selecting asphalt as a binder, mixing the asphalt and coke powder according to the mass ratio of 2.5:7.5, and fully and uniformly mixing the mixed powder by adopting a kneader, wherein the specific ratio is as follows: putting the mixed powder of the asphalt and the coke powder into a kneader, heating to 473K, and mixing for 60 min; taking out the mixed materials, rolling the mixed materials into 2mm slices by a roller press, and repeatedly rolling for 3 times; after the thin slices are dried in the air, the thin slices are crushed and ground into 10 mu m mixed material by a Raymond mill for standby; the coke powder and the pore-forming template 100 are loaded into the mold jacket, which is the same as that in the embodiment 1, and will not be described herein for brevity.

The isostatic compaction rotor blank comprises the following steps:

firstly, carrying out vacuum-pumping degassing treatment on a mold sheath containing coke powder and a pore-forming template 100, wherein the vacuum degree is less than or equal to 0.75MPa, and the vacuum degree is 0.7MPa in the embodiment; secondly, placing the die sheath into a high-pressure cylinder, applying isostatic pressure to the die sheath at the speed of 2.5MPa/s to 200MPa, and maintaining the pressure for 20 min; then, the pressure is reduced at the speed of 2MPa/s to reduce the pressure to normal pressure, and then, the rotor blank is obtained after demoulding.

Step S3, baking treatment: and (3) putting the rotor blank into a roasting furnace for sintering to convert the rotor blank into a carbonized composite material, and discharging organic volatile matters contained in the rotor blank in the sintering and curing process. The sintering process of this example is specifically as follows: firstly, heating from room temperature to 393K at a heating rate of 10K/min, and keeping the temperature for 0.8h to promote the volatilization of asphalt; then, heating to 593K at the heating rate of 8K/min, and preserving heat for 1.25h to promote the decomposition of the organic components of the asphalt; then, heating to 973K at the heating rate of 2K/h, and preserving heat for 4 h; then, heating to 1173K at the heating rate of 3K/h, and preserving heat for 200h to promote full carbonization of the asphalt; finally, the temperature is preferably reduced at a rate of less than or equal to 50K/h, in this example, at a rate of 40K/h until the temperature is reduced to room temperature, which is regarded as the end of the calcination treatment of the blank. At this point, the rotor blank is converted into a carbonized composite material.

Step S4, graphitizing and sintering: and (3) putting the carbonized composite material into an Acheson graphitizing furnace for graphitizing and sintering to convert the carbonized composite material into a graphite composite material. The graphitization sintering process comprises the following steps: heating from room temperature to 1573K at a heating rate of 10K/min, and keeping the temperature for 40 min. Then, heating to 2873K at the heating rate of 3K/min, and preserving the heat for 80 min; finally, the temperature is preferably reduced at a rate of ≦ 50K/h, in this embodiment, the temperature is reduced at a rate of 40K/h until the temperature is reduced to the room temperature, which is regarded as that the graphitization treatment process of the carbonized composite material is completed. At this time, the carbonized composite material is converted into a graphite composite material.

Step S5, X-ray observation of the internal structure of the graphite composite material: and (3) carrying out three-dimensional observation on the internal organization of the graphite composite material by adopting an X-ray machine, and accurately marking the position of the annular hollow-out body 50 made of the 18Ni300 material in the graphite composite material. Step S6, machining the graphite composite material: processing the graphite composite material according to the position mark of the annular hollow body 50 made of the metal material until the outer side part of the annular hollow body 50 made of the 18Ni300 material is exposed. Step S7, removing the metal template: an acidic corrosive liquid mixed by nitric acid, hydrochloric acid, acetic acid and water is prepared according to the characteristics of the 18Ni300 material. Wherein, the molar ratio of nitric acid, hydrochloric acid, acetic acid and water in the acidic corrosive liquid is as follows: HNO₃:HCl:CH₃COOH:H₂And (3) soaking the graphite composite material in the acidic corrosive liquid, and removing the annular hollow-out bodies 50 made of the metal and the branches 30 made of the metal in an acid-washing corrosion mode, so that an ordered array macroporous structure is obtained in the graphite composite material. And then, three-dimensionally observing the internal tissue of the graphite composite material by using an X-ray machine again to determine that the 18Ni300 annular hollow body and the 18Ni300 branches are completely removed, and obtaining the ordered macroporous (≦ 1mm) graphite composite material required by developing a novel graphite rotor.

Example 3

The embodiment 3 of the invention provides a controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining, which comprises the following steps:

in step S1, a pore-forming template 100 is provided, and the structure of the pore-forming template 100 is the same as that of embodiment 1, and will not be described herein for brevity. The pore-forming template 100 is formed by a 3D printing technology, and may specifically include the following steps:

determining the outline dimension of a graphite rotor blank according to the final dimension parameters of the graphite rotor: according to the diameter D of the graphite rotor₁And the total height H of the graphite rotor₁And (figure 2), adding corresponding machining allowance of 10mm on each contour surface of the graphite rotor, and reserving a height allowance of 300mm, namely taking D in the embodiment₂＝D₁+10mm，H₂＝H₁+300mm。

Determining the position of the annular hollowed-out body 50 area according to the parameters of the graphite rotor to be prepared: the outer diameters D1 and 0.75. D of the graphite rotor₁The size of the graphite rotor is that a circle is drawn for the diameter, the impeller outline of the graphite rotor is intersected with the two drawn circles, and the formed area is seen from the viewIs the area where the annular hollow-out body 50 is located;

the aperture of the graphite rotor nozzle is optimized according to the formula (3), and the aperture d of the nozzle is taken in the embodiment_nozzle＝0.8mm。

Determining the size parameter of the crown structure: the crown structure is constructed using an octahedron as a basic unit consisting of eight connecting rods 51 making an angle α of 55 ° (critical forming angle) with the horizontal plane. Connecting rod 51 diameter d of octahedral unit_cylinThe value range is represented by the formula (2) d_cylin＝d_nozzleDetermining the thickness of the film as 0.2-0.8 mm: in this example, d is taken_cylin＝0.8mm。

Diameter d of spherical node 55 in this embodiment_sphere3 mm. And (3) piling the octahedral units in space at the area position of the crown structure in a three-dimensional array and Boolean operation mode to generate the crown structure mathematical model. To ensure the function of the mounting hole 57, the diameter d of the mounting hole 57 is set_assemBy the formula (5) d_assem≈3·d_cylin+0.15 mm.

Determination of the size parameters of the branches 30: diameter d of first link 34 in limb 30_stemAnd length l_stemIs determined by equations (6) and (7), respectively: in this example, d is taken_stem＝4.5·d_cylin，l_stem＝0.3·D₁. Diameter d of V-shaped rod 231 and second connecting rod 322 in branch rod 32_branchDetermined by equation (8): this example takes l_stem＝3·d_cylin。

Preferably, the volume ratio of the inner pores of the graphite rotor blank is as follows: in the embodiment, the preferred pore volume ratio is 0.02-0.05, and the volume ratio of the pores in the graphite rotor blank is verified as follows: calculating the volume V of the graphite rotor blank by the formulas (9), (10) and (11)₁Volume V of 'axial tree' template_modelAnd the volume of the inner pores of the graphite rotor blank accounts for phi, if the phi value is not in the interval of 0.02,0.05]In the above step, the size of the pore-forming template 100 is modified and designed until the value of the pore volume ratio Φ is within the interval [0.02,0.05 ]]In (1).

Step S12, determination of the material quality of the pore-forming template 100: the annular hollow-out body 50 and the branches 30 are both prepared from powder made of 17-4 PH materials, and photosensitive resin C-UV 9400 is preferably used as a material for forming the trunk 10.

step a, metal powder pretreatment: and (3) loading 17-4 PH powder with the particle size of 53 microns by using a ceramic vessel, then putting the ceramic vessel into a vacuum oven, heating to 373K, preserving heat for 2 hours, taking out the dried 17-4 PH powder, and screening by using a 280-mesh screen for later use.

Step b, preparing for metal 3D printing: forming the annular hollowed-out body 50 and the branches 30 by adopting powder bed laser melting (SLM) metal 3D printing equipment, specifically, performing sand blasting treatment on a titanium alloy substrate material, and then installing the titanium alloy substrate material into a forming cylinder; then, the forming cylinder descends one layer thickness (60 mu m), and the powder supply cylinder correspondingly ascends one layer thickness; scraping powder in the powder supply cylinder into the forming cylinder by a scraper, uniformly paving a layer of 17-4 PH powder on the surface of the substrate, and scraping redundant powder into a recovery cylinder; subsequently, the substrate is preheated to 350K, high-purity Ar gas is introduced into the forming chamber, and meanwhile, the oxygen content in the forming chamber is controlled to be lower than 0.1 percent.

Step c, determining the metal 3D forming parameters of the annular hollow-out body 50 and the branches 30: and (3) importing the three-dimensional models of the annular hollow bodies 50 and the branches 30 into special data processing software to perform slicing, path planning and printing parameter processing, and manufacturing a processable data project. For the fine features of the annular hollow-out body 50 and the branches 30, the preferred process parameters are as follows: laser scanning power 300W; the diameter of the light spot is 100 mu m; the scanning speed is 1500 mm/s; the scanning pitch is 100 μm; the layer thickness is 60 μm;

step D, forming the annular hollow-out body 50 and the branches 30 by metal 3D: and after the parameters of the 3D printing equipment, such as oxygen content, substrate temperature, inert gas and the like, reach set conditions, clicking a start button to start printing. Under the control of the scanning galvanometer, the laser beam rapidly scans 17-4 PH powder according to the cross-sectional shapes of the current layers of the annular hollow bodies 50 and the branches 30, so that the powder is melted → solidified to form a cladding layer. Along with the scanning of the current layers of the annular hollow-out body 50 and the branches 30, the titanium alloy substrate descends by one layer thickness, and the powder supply cylinder correspondingly ascends by one layer thickness. And (3) paving a layer of 17-4 PH powder on the substrate again by using a scraper, then scanning the next layer of the annular hollow body 50 and the branch 30, and repeating the process until the annular hollow body 50 and the branch 30 are molded.

Step e, post-processing the annular hollow-out body 50 and the branches 30: and (3) placing the formed annular hollow-out body 50 and the branches 30 into a vacuum furnace, heating to 1123K, and preserving heat for 4h to eliminate internal stress. And after furnace air cooling, taking out, and cutting and separating the annular hollow bodies 50 and the branches 30 from the titanium alloy substrate.

Step S13, preparing the backbone 10 by 3D printing, which specifically includes the steps of:

step S131, determining the light curing molding parameters of the stem 10: converting a three-dimensional model of the backbone 10 into a file in an STL format for exporting, then adopting specific slicing software to slice the model of the STL file to obtain data of a cross section layer of the backbone 10, then importing the data into an SLA photocuring printer system, designing a scanning path by the system, and accurately controlling the movement tracks of a laser scanner and a lifting platform. For the geometrical characteristics of the stem 10, the preferred process parameters are: the profile scanning speed is 8000 mm/s; the filling scanning speed is 2000 mm/s; the supporting scanning speed is 2000 mm/s; jump across speed 30000 mm/s; the feeding speed of the working table is 5 mm/s.

Step S132, light-curing the molded stem 10: projecting a laser beam into the liquid photosensitive resin according to a designed scanning path through a scanner, and solidifying the resin in a specific area to form a cross-section layer of the trunk 10; subsequently, the lifting platform is lowered by one section layer thickness, the resin is made to flow and cover on the cured layer, and then the next section layer of the trunk 10 is cured by the laser; the above process is repeated until the entity of the backbone 10 is formed by overlapping layer by layer.

Step S14, assembling the heterogeneous material coupled "axial tree" template: assembling the 17-4 PH branch 30, the 17-4 PH annular hollow body 50 and the photosensitive resin main stem 10 in sequence to obtain the 'arbor' pore-forming template 100 structure.

Step S2, isostatic pressing a rotor blank: and (3) putting the coke powder and the pore-forming template 100 into a mold sheath, and performing isostatic pressing to obtain a rotor blank. Mould bagInner diameter D of the sleeve₃And height H₃Are determined by equations (12) and (13), respectively: in this embodiment, D₃＝1.5·D₂，H₃＝1.5·H₂。

In the embodiment, before the step of isostatic pressing the rotor blank, the method further comprises the step of pretreating the coke powder: crushing and grinding the coke powder by using a Raymond mill to obtain the coke powder with the particle size of 12 mu m; selecting asphalt as a bonding agent, mixing the asphalt and coke powder according to the mass ratio of 3:7, and fully and uniformly mixing the mixed powder by adopting a kneader, wherein the specific ratio is as follows: heating the mixed powder of the asphalt and the coke powder in a kneader to 513K, and mixing for 80 min; taking out the mixed material, rolling the mixed material into a sheet with the thickness of 3mm by using a roller press, and repeatedly rolling for 4 times; after the thin slices are dried in the air, the thin slices are crushed and ground into mixed materials with the grain diameter of 12 mu m by a Raymond mill for later use. The coke powder and the pore-forming template 100 are loaded into the mold jacket, which is the same as the first embodiment, and will not be described herein for brevity.

The isostatic compaction rotor blank comprises the following steps:

firstly, carrying out vacuum-pumping degassing treatment on a mold sheath filled with coke powder and a pore-forming template 100, wherein the vacuum degree is less than or equal to 0.75MPa (0.75 MPa in the embodiment); and secondly, placing the die sleeve into a high-pressure cylinder, applying isostatic pressure to the die sleeve at the speed of 3MPa/s to 300MPa, and maintaining the pressure for 30 min. Then, the pressure is reduced to normal pressure by using the speed of 3MPa/s, and then, the rotor blank is obtained by demoulding.

Step S3, baking treatment: and (3) putting the rotor blank into a roasting furnace for sintering to convert the rotor blank into a carbonized composite material, and discharging organic volatile matters contained in the rotor blank in the sintering and curing process. The sintering process is specifically as follows: firstly, heating from room temperature to 423K at a heating rate of 15K/min, and keeping the temperature for 1 h; then, heating to 633K at the heating rate of 10K/min, and preserving heat for 1.5 h; then, heating to 1023K at the heating rate of 3K/h, and preserving heat for 5 h; then, heating to 1278K at the heating rate of 5K/h, and preserving the heat for 240 h; and finally, cooling at the speed of 50K/h until the temperature is reduced to the room temperature, and determining that the roasting treatment of the blank is finished. At this point, the rotor blank is converted into a carbonized composite material.

Step S4, graphitizing and sintering: the graphitization sintering process comprises the following steps: heating from room temperature to 1773K at a heating rate of 15K/min, and keeping the temperature for 60 min. Then, heating to 3073K at the heating rate of 5K/min, and preserving the heat for 120 min; and finally, cooling at the speed of 50K/h until the temperature is reduced to the room temperature, and at the moment, converting the carbonized composite material into the graphite composite material.

Step S5, X-ray observation of the internal structure of the graphite composite material: and (3) carrying out three-dimensional observation on the internal organization of the graphite composite material by adopting an X-ray machine, and accurately marking the position of the annular hollow body 50 made of the 17-4 PH material in the graphite composite material. Step S6, machining the graphite composite material: and processing the graphite composite material according to the position marks of the annular hollow bodies 50 made of the 17-4 PH materials until the outer side parts of the annular hollow bodies 50 made of the 17-4 PH materials are exposed. Step S7, removing the metal template: preparing an acidic etching solution mixed by hydrofluoric acid, nitric acid and water according to the characteristics of the material with the pH of 17-4. Wherein, the molar ratio of hydrofluoric acid, nitric acid and water in the acidic corrosive liquid is as follows: HF: H₃NO₃:H₂O ═ 1:2: 97; the graphite composite material is soaked in the prepared acidic corrosive liquid, and the annular hollow bodies 50 made of metal materials and the branches 30 made of 17-4 PH materials are removed in an acid pickling corrosion mode, so that the ordered array macroporous structure is obtained in the graphite composite material.

It is understood that, in other embodiments, the steps S5-S6 may be omitted, and at this time, the outer periphery of the rotor blank is directly processed to expose the outer side portion of the annular hollow-out body 50 made of metal material. It can be understood that the controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining further includes a step of performing finish machining on the material from which the metal template is removed to obtain the shape of the graphite rotor as shown in fig. 2, which belongs to the prior art and is not described herein for brevity.

Since the nozzle aperture of the present embodiment is small (less than or equal to 1mm), the diameters of the branches 30 and the connecting rods 51 and the aperture of the mounting channel 17 are also small, so that the present embodiment adopts a 3D printing technology to prepare the pore-forming template 100, which can improve the processing precision of the pore-forming template 100. In order to meet the requirement of the 3D printing device, the material of the main stem 10 of this embodiment is photosensitive resin C-UV 9400, and it can be understood that when the main stem 10 is prepared by other methods, the main stem 10 may also be made of other organic materials.

The above description is intended to describe in detail the preferred embodiments of the present invention, but the embodiments are not intended to limit the scope of the claims of the present invention, and all equivalent changes and modifications made within the technical spirit of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A controlled synthesis process of a functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining is characterized by comprising the following steps:

2. The controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining as claimed in claim 1, wherein before the step of isostatic compaction of the rotor blank, further comprising the step of pre-treating the coke powder: crushing and grinding the coke powder by using a Raymond mill to obtain the coke powder with the particle size of 5-12 mu m; selecting asphalt as a bonding agent, mixing the asphalt and the coke powder according to the mass ratio of 2: 8-3: 7, and uniformly mixing the mixed powder.

3. The controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining of claim 2, wherein the step of mixing the powders uniformly comprises: putting the mixed powder of the asphalt and the coke powder into a kneader, heating to 433-513K, and mixing for 40-80 min; taking out the mixed materials, rolling the mixed materials into a sheet with the thickness of 1-3 mm by using a roller press, and repeatedly rolling for 2-4 times; and after the thin sheet is dried, crushing and grinding the thin sheet into a mixed material with the particle size of 5-12 microns by using a Raymond mill again for later use.

4. The process for controlled synthesis of a functionalized ordered macroporous (≦ 1mm) graphite rotor for refining of aluminum alloy according to claim 1, wherein the isostatic compaction of the rotor blank comprises the steps of:

carrying out vacuum-pumping degassing treatment on a mold sheath filled with coke powder and a pore-forming template, wherein the vacuum degree is less than or equal to 0.75 MPa;

placing the mold sheath into a high-pressure cylinder, applying isostatic pressure to the mold sheath at a rate of 1-3 MPa/s to 150-300 MPa, and maintaining the pressure for 10-30 min;

and (3) reducing the pressure at the speed of 1-3 MPa/s to reduce the pressure to normal pressure, and then demolding to obtain the rotor blank.

5. The controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining according to claim 1, wherein the roasting treatment comprises the following steps:

firstly, heating to 373-423K from room temperature at a heating rate of 5-15K/min, and keeping the temperature for 0.5-1 h to promote the volatilization of asphalt; then, heating to 573-633K at a heating rate of 5-10K/min, and preserving the heat for 1-1.5 hours to promote the decomposition of organic components of the asphalt; then, heating to 923 to 1023K at the heating rate of 1 to 3K/h, and preserving heat for 2 to 5 h; then heating to 1123-1278K at the heating rate of 2-5K/h, and preserving heat for 192-240 h to promote asphalt carbonization; finally, the temperature is reduced at a rate of ≦ 50K/h until the temperature is reduced to room temperature.

6. A process for the controlled synthesis of a functionalized ordered macroporous (≦ 1mm) graphite rotor for the refining of aluminium alloys according to claim 1, wherein the graphitization sintering treatment comprises the steps of:

heating the mixture from room temperature to 1473-1773K at the heating rate of 5-15K/min, and preserving the heat for 30-60 min; then, heating to 2473-3073K at the heating rate of 2-5K/min, and preserving heat for 60-120 min; and finally, cooling at the speed of ≦ 50K/h until the temperature is reduced to the room temperature, and finishing the graphitization treatment process of the carbonized composite material.

7. The controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining according to claim 1, wherein the trunk is formed by sequentially sleeving a top hollow cylinder, N middle hollow cylinders and a bottom hollow cylinder.

8. The controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining as claimed in claim 1, wherein the annular hollow comprises a plurality of sector ring tree crown regions and sector ring side branch regions connected between two adjacent sector ring tree crown regions, the radius of the sector ring tree crown regions is larger than that of the sector ring side branch regions, the sector ring tree crown regions and the sector ring side branch regions are formed by stacking and splicing octahedrons formed by connecting rods on space in a three-dimensional array and Boolean operation mode, each octahedron is formed by eight connecting rods having an included angle α ≧ 40 ° with the horizontal plane, the junctions of the connecting rods are connected by spherical nodes, the spherical node located on the innermost side of the annular hollow forms an assembly spherical node, the assembly spherical node is provided with an assembly hole, and one end of the branch stem opposite to the trunk is inserted into the corresponding assembly hole.

9. The controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining according to claim 1, wherein the pore-forming template has multiple sets of branches, and the multiple sets of branches are arranged at intervals along the axial direction of the trunk; the even interval distribution of circumference that a plurality of branches in each group's branch encircle the trunk, each branch includes branch pole and many first connecting rods, many first connecting rods arrange along the circumference of trunk equal angle interval, the branch pole includes a plurality of V-arrangement poles that connect gradually and the second connecting rod that one end and the open end of V-arrangement pole are connected, the pointed end of V-arrangement pole is connected with the one end of first connecting rod, the other end of second connecting rod is connected with annular fretwork body through the pilot hole of assembling spherical node, the other end of first connecting rod is pegged graft on the trunk.

10. A graphite rotor characterized by being prepared by the controlled synthesis process of the functionalized ordered macroporous (≦ 1mm) graphite rotor for aluminum alloy refining according to any one of claims 1 to 9.