阅读说明：本技术 一种空心管微点阵结构陶瓷材料的制备方法 (Preparation method of hollow tube micro-lattice structure ceramic material ) 是由 张斗 赵连仲 王小峰 熊慧文 于 2020-06-16 设计创作，主要内容包括：本发明提供了一种空心管微点阵结构陶瓷材料的制备方法,包括如下步骤：将熔融态的改性陶瓷先驱体通过直写成形装置,于保护气氛下打印获得三维点阵结构的粗坯,然后将三维点阵结构的粗坯在交联气氛下进行不完全交联反应,获得不完全交联的坯体,去除坯体中未交联的部分,获得空心管微点阵先驱体支架,再进行热解即得空心管微点阵结构陶瓷材料。本发明借助增材制造技术结合后续热处理得到结构独特的陶瓷材料,克服了以往空心管微点阵材料造价高昂、工艺复杂的弊端,实现了管壁厚度在1～100μm之间的调控。保证材料在具有低密度的同时,保持了陶瓷高强度、高硬度,优异的化学稳定性与热稳定性,同时获得了结构多样,形状复杂的陶瓷样件。(The invention provides a preparation method of a hollow tube micro-lattice structure ceramic material, which comprises the following steps: printing the molten modified ceramic precursor in a protective atmosphere through a direct writing forming device to obtain a rough blank of a three-dimensional lattice structure, then carrying out incomplete crosslinking reaction on the rough blank of the three-dimensional lattice structure in a crosslinking atmosphere to obtain an incompletely crosslinked blank, removing the part which is not crosslinked in the blank to obtain a hollow tube micro-lattice structure precursor support, and then carrying out pyrolysis to obtain the hollow tube micro-lattice structure ceramic material. The ceramic material with a unique structure is obtained by combining an additive manufacturing technology with subsequent heat treatment, the defects of high manufacturing cost and complex process of the traditional hollow tube microarray material are overcome, and the regulation and control of the thickness of the tube wall between 1 and 100 mu m are realized. The ceramic sample piece with various structures and complex shapes is obtained while the high strength, high hardness, excellent chemical stability and excellent thermal stability of the ceramic are maintained while the low density of the material is ensured.)

1. A preparation method of a hollow tube micro-lattice structure ceramic material is characterized by comprising the following steps: the method comprises the following steps:

printing the molten modified ceramic precursor in a protective atmosphere through a direct writing forming device to obtain a rough blank of a three-dimensional lattice structure, then carrying out incomplete crosslinking reaction on the rough blank of the three-dimensional lattice structure in a crosslinking atmosphere to obtain an incompletely crosslinked blank, removing the part which is not crosslinked in the blank to obtain a hollow tube micro-lattice structure precursor support, and then carrying out pyrolysis to obtain the hollow tube micro-lattice structure ceramic material.

2. The method for preparing the ceramic material with the hollow tube microarray structure according to claim 1, wherein the method comprises the following steps:

the molten state modified ceramic precursor is a substance obtained by modifying the ceramic precursor by a modifier, the obtained modified ceramic precursor powder is heated to 250-300 ℃ to obtain molten state, the ceramic precursor is polycarbosilane, and the modifier is at least one selected from polypropylene, hyperbranched liquid polycarbosilane, liquid polyvinyl silane and polydimethylsiloxane.

3. The method for preparing a hollow tube microarray structure ceramic material according to claim 1 or 2, wherein:

the molten state modified ceramic precursor is used for 10s^-1The viscosity under the shearing rate is 100 Pa.s-1000 Pa.s, and the molecular weight of the polycarbosilane is 1000-2000 g/mol.

4. The method for preparing the ceramic material with the hollow tube microarray structure according to claim 2, wherein the method comprises the following steps:

the specific process of modifying the ceramic precursor by the modifier comprises the following steps: adding polycarbosilane and a modifier into an organic solvent, reacting for 4-8 h at 100-140 ℃ to obtain a mixed solution, drying the mixed solution, grinding and sieving, and taking undersize products to obtain the polycarbosilane modified organic silicon material.

5. The method for preparing the ceramic material with the hollow tube microarray structure according to claim 4, wherein the method comprises the following steps:

the addition amount of the modifier is 1-5 wt% of the mass of the ceramic precursor;

the organic solvent is at least one of xylene, tetrahydrofuran and toluene;

the drying temperature is 100-140 ℃, the drying time is 12-24 hours, and the drying pressure is less than or equal to-0.1 MPa;

the mesh number of the screen used for sieving is 100 meshes.

6. The method for preparing the ceramic material with the hollow tube microarray structure according to claim 1, wherein the method comprises the following steps:

the crosslinking atmosphere is selected from one of air, ozone, chlorine, cyclohexene, n-heptene and octyne;

the temperature of the incomplete crosslinking reaction is 180-220 ℃, and the time of the incomplete crosslinking reaction is 1-23 h.

7. The method for preparing the ceramic material with the hollow tube microarray structure according to the claim or the claim, which is characterized in that:

and (3) placing the incompletely crosslinked blank body in an organic solvent for soaking for 12-24 hours, and removing the uncrosslinked part in the blank body, wherein the organic solvent is one selected from xylene, tetrahydrofuran and toluene.

8. The method for preparing the ceramic material with the hollow tube microarray structure according to claim 1, wherein the method comprises the following steps:

the pyrolysis procedure is that the temperature is raised to 1000-1200 ℃ at the speed of 5-10 ℃/min, and the temperature is kept for 1-2 h.

9. The method for preparing the ceramic material with the hollow tube microarray structure according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:

step one

Adding polycarbosilane and a modifier into an organic solvent, reacting for 4-8 hours at 100-140 ℃ under stirring to obtain a mixed solution, keeping the temperature of the mixed solution at 100-140 ℃ under the pressure of less than or equal to-0.1 MPa for 12-24 hours to obtain a block, grinding, and sieving with a 100-mesh sieve to obtain undersize products to obtain modified ceramic precursor powder.

Step two

Placing the modified ceramic precursor powder obtained in the step one in a printing needle cylinder, introducing nitrogen into the needle cylinder, heating to 250-300 ℃ at the speed of 5-10 ℃/min, preserving the temperature for 30-60 min, removing bubbles, and obtaining a molten modified ceramic precursor, wherein the molten modified ceramic precursor is heated for 10s^-1The viscosity at a shear rate is 100Pa.s to 1000Pa.s,

simultaneously setting the temperature of a forming platform of the direct-writing forming device to be 150-195 ℃, and printing on the platform through a designed printing program to obtain a rough blank with a three-dimensional lattice structure;

step three

Placing the rough blank with the three-dimensional lattice structure obtained in the second step in a crosslinking atmosphere for carrying out incomplete crosslinking reaction to obtain an incompletely crosslinked blank body, wherein the flow rate of the crosslinking atmosphere is 40-60 ml/min, the crosslinking atmosphere is selected from one of air, ozone, chlorine, cyclohexene, n-heptene and octyne, the temperature of the incomplete crosslinking reaction is 180-250 ℃, and the time of the incomplete crosslinking reaction is 1-23 h;

step four

Cutting the end part of the incompletely crosslinked green body obtained in the step three, placing the incompletely crosslinked green body in an organic solvent for soaking for 12-24 h, removing the part which is not crosslinked in the green body to obtain the hollow tube microarray precursor bracket, wherein the organic solvent is one selected from dimethylbenzene, tetrahydrofuran and methylbenzene,

step five

And (4) heating the hollow tube micro-lattice precursor support obtained in the fourth step to 1000-1200 ℃ at a speed of 5-10 ℃/min under a protective atmosphere, and carrying out heat preservation for 2h for pyrolysis to obtain the hollow tube micro-lattice structure ceramic material.

10. The method for preparing the ceramic material with the hollow tube microarray structure according to claim 9, wherein the method comprises the following steps:

in the second step, the modified ceramic precursor powder is loaded into a needle cylinder and is connected with a needle head, a piston and an air duct, and then the whole body is arranged on a clamp on a Z axis; introducing nitrogen into the needle cylinder, heating to 250-300 ℃ at the speed of 5-10 ℃/min, preserving the temperature for 30-60 min, removing bubbles to obtain a molten modified ceramic precursor, simultaneously setting the temperature of a forming platform of the direct-writing forming device to be 150-195 ℃, then automatically controlling the air pressure of the needle cylinder arranged on a Z axis by a computer by means of the three-dimensional structure pattern required by computer-aided design, so that slurry flows out of a needle nozzle and is deposited on an X-Y axis forming platform moving according to a program, thereby obtaining a first layer structure; thereafter, the Z-axis is moved or rotated precisely upwards to a height determined by the structural solution, and the second layer formation will be carried out on the first layer structure; and then, obtaining a rough blank with a three-dimensional lattice structure in a layer-by-layer superposition mode, wherein the air pressure range is 1-1000 PSI, and the moving speed of the forming platform is 0.1-500 mm/s.

Technical Field

The invention belongs to the technical field of light porous functional materials, and particularly relates to a preparation method of a hollow tube micro-lattice structure ceramic material.

Background

The 3D printing technology is to digitally slice a three-dimensional model into a two-dimensional cross section, and add and manufacture parts in a point-by-point, line-by-surface mode, so that a structure which is difficult to process or cannot be processed by the traditional process can be realized. Among them, the direct writing molding technology was proposed as an inexpensive 3D printing technology by Joseph Cesarano III and the like of Sandia national laboratory in the united states for the first time. The method can achieve large aspect ratios and size control ranges, and can achieve three-dimensional structures with unsupported features. The ink used for printing has high design freedom of the components of the raw materials, and can realize the three-dimensional forming of metal, ceramic and even living cells.

The lattice material is a novel light multifunctional material which is produced along with the development of aviation aerospace beams and the progress of processing technology in recent years. The periodic structural units in the lattice material can realize the special properties of high specific strength and high energy absorptivity while keeping low density and high porosity. The preparation of the ceramic micro-lattice structure usually prepares a skeleton structure by means of a template method, then prepares a ceramic film to cover the template by methods such as film deposition and the like, and finally removes the template to obtain the micro-lattice ceramic material. Such as: bauer J, Hengsbach S, Tesari I, et al, High-string cellular ceramics with 3D microarchitecture [ J ]. Proceedings of the National academy of Sciences,2014,111(7), 2453-2458.Jang D, Meza L R, Greer F, et al, Fabricationand development of this-dimensional porous ceramics [ J ]. Nature, 2013,12(10) 893-898.Meza L R, Das, Greer J R.Strong, lightweight, and dryenvironmental-dimensional ceramics [ J ] 6202, 2014, FIGS.

The preparation of the microarray ceramic material by using the template method usually needs to be combined with a thin film deposition technology, and has complex process route and high cost. Meanwhile, the wall thickness of the hollow tube of the lattice material is limited to a smaller size (less than or equal to 10 μm), and the inner diameter of the hollow tube is limited to the diameter of the corresponding template, which greatly limits the designability of the structure.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a preparation method of a ceramic hollow tube micro-lattice structure. Firstly, preparing a ceramic precursor three-dimensional micro-lattice support by using a direct writing forming technology; then, incomplete cross-linking treatment is carried out on the ceramic precursor bracket, so that the cross-linking of the precursor surface layer is realized, and the thickness of the final ceramic hollow pipe wall can be controlled by controlling the cross-linking time and the cross-linking atmosphere; then, the non-crosslinked part is chemically etched or ablated to obtain a hollow tube micro-lattice precursor bracket, and finally, the hollow tube micro-lattice ceramic material is obtained through high-temperature pyrolysis. The preparation method of the invention has low cost and high structural design.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention relates to a preparation method of a hollow tube micro-lattice structure ceramic material, which comprises the following steps:

printing the molten modified ceramic precursor in a protective atmosphere through a direct writing forming device to obtain a rough blank of a three-dimensional lattice structure, then carrying out incomplete crosslinking reaction on the rough blank of the three-dimensional lattice structure in a crosslinking atmosphere to obtain an incompletely crosslinked blank, removing the part which is not crosslinked in the blank to obtain a hollow tube micro-lattice structure precursor support, and then carrying out pyrolysis to obtain the hollow tube micro-lattice structure ceramic material.

Drawings

FIG. 1 is an optical photograph of the surface and sides of a blank printed in example 1;

FIG. 2 is an electron scanning microscope picture of the three-dimensional SiC hollow tube structure obtained in example 1;

FIG. 3 is a plot of the final wall thickness of the tube obtained for different cross-linking times at 200 ℃ in example 1.

Detailed Description

The invention is further illustrated, but not limited, by the following examples: