CN110668827A - A method for 3D printing textured self-lubricating ceramic materials - Google Patents

Abstract

The invention relates to a method for 3D printing textured self-lubricating ceramic materials. Drawing software is used to draw three-dimensional model diagrams of different surface textures, and then 3D printing technology is used to print a ceramic precursor with surface textures. The characteristics of the material: After high-temperature sintering, a lubricant is mounted on the surface to achieve a synergistic effect of structure and lubrication. The geometric parameters such as the topography of the surface texture are precisely controlled by 3D printing technology, which facilitates the realization of the synergistic effect of the structure and the lubricant. The invention has flexible structure design, can be formed at one time for surface structure and material preparation, simple process operation, high repeatability, short time consumption and low cost, and is suitable for printing of ceramic materials such as Al ₂ O ₃ , ZrO ₂ and SiO ₂ . 3D printing textured self-lubricating ceramic materials for aerospace high temperature sliding sealing systems.

Description

A method for 3D printing textured self-lubricating ceramic materials

technical field

The invention belongs to self-lubricating ceramic material printing, and relates to a method for 3D printing textured self-lubricating ceramic materials.

Background technique

As a promising class of self-lubricating materials, ceramic materials have high strength, high hardness, low density, and excellent wear resistance, corrosion resistance and high temperature resistance. They are suitable for ultra-high temperature sliding seals in the aerospace field. Best candidate material. However, the most prominent problem of ceramic materials is that the friction coefficient and wear rate are very high at high temperature, so it is necessary to take effective anti-friction and anti-wear methods to improve their high-temperature tribological properties. At present, the theoretical research and engineering practice of many scholars have shown that the friction surface is not as smooth as possible, the surface is too smooth to effectively carry lubricant, and the quality of the lubricating film formed between the two surfaces is poor, which is not conducive to lubrication; The surface of the friction pair with surface roughness and micro-geometry can not only store the lubricant well, but also reduce the contact area between the friction pairs, so as to achieve the purpose of lubrication.

Surface texture technology is to process the surface micro-shapes with certain shape, size and arrangement on the surface of the friction pair, which has become an effective means to improve the lubrication performance. The main processing methods are laser surface texturing (LST), surface laser shot peening (LPT), photolithography (LIGA), reactive ion etching (RIE), embossing technology, electrical discharge machining, electrical machining, etc. Laser surface texturing is widely used for its relatively high precision, versatility, flexibility and pollution-free advantages, but there is a high-energy laser beam irradiating the surface of the material to melt and vaporize it instantly, resulting in a heat-affected zone on the surface of the workpiece. The problem of changes in microstructure and mechanical properties, bulges and burrs are prone to appear near the texture, which requires "secondary processing", which consumes a lot of energy and reduces the preparation efficiency, and can only process simple geometric patterns. It is difficult to process and control the bionic pattern; the surface laser shot peening has great environmental pollution, difficult control and low precision; the processing cost of lithography technology is high; reactive ion etching technology needs to use auxiliary devices or special environments; embossing The technical process is complex and the cost is high; the EDM technology consumes a lot and the cost is high. For example, Chinese patent CN 201711395150.7 discloses a preparation method of a laser micro-textured surface vacuum plasma self-lubricating coating. The method is to use laser scanning to process a circular pit micro-texture on the metal surface, and then spray a NiAlMo bonding layer on the surface to Reduce the friction coefficient and wear amount of the metal surface; Chinese patent CN 201710091779.6 discloses a preparation method of a micro-textured self-lubricating ceramic guide rail, using femtosecond laser processing technology to process micro-holes on the ceramic surface, and then filling with solid lubricant. As far as the existing surface texture processing technology is concerned, there are single surface textures that can be designed and processed, limited to simple geometric patterns, low processing accuracy, prone to bulges and burrs, high energy consumption, high cost, and low processing efficiency. and other shortcomings.

As a kind of additive manufacturing, 3D printing technology uses points, lines or surfaces as basic units for layer-by-layer manufacturing, which can realize rapid prototyping of complex structures that cannot or are difficult to achieve by traditional methods, with easy operation and low production costs. , short cycle, flexible structure design and other advantages. Therefore, 3D printing microtexture technology is combined with ceramic materials to realize the integration of material preparation and texture, so as to achieve the purpose of ultra-high temperature lubrication. Chinese patent CN201710927442.4 discloses a 3D printing manufacturing method for the surface microtexture of friction pair, but this method is to import the designed three-dimensional model into the robot hand control device, and perform laser sintering treatment on the surface of the friction pair. Selective laser sintering technology.

SUMMARY OF THE INVENTION

technical problem to be solved

In order to avoid the deficiencies of the prior art and in view of the technical defects of the prior art, the present invention proposes a method for 3D printing textured self-lubricating ceramic materials. Lubricate ceramic materials. The purpose is to precisely control the geometric parameters such as the topography of the surface texture through 3D printing technology, so as to facilitate the realization of the synergistic effect of the structure and the lubricant. The idea of the present invention is to use drawing software to draw three-dimensional model diagrams of different surface textures, and then use 3D printing technology to print out ceramic precursors with surface textures. synergy.

Technical solutions

One step 1. Design and draw surface texture: design surface textures with different geometric parameters, use SolidWorks drawing software to draw a three-dimensional model, and save it as an STL format file;

Step 2. Computer slicing processing: Open the STL format file formed in step 1 in the slicing software, adjust the position and zoom size of the 3D model on the platform, set the layer thickness of the printing material to 55 μm, and the number of layers of the base plate to 5 layers to obtain The sliced file;

Step 3. 3D printing: Copy the sliced file to a 3D printer, and use ceramic slurry to print ceramic preforms with different surface textures;

Step 4. High temperature sintering: the obtained ceramic preform is placed in a box furnace for sintering, and the temperature is raised to 300°C, 600°C, and 900°C for 2 hours each, and the temperature is raised to 1500°C for 3 hours, and then cooled to room temperature. until;

Step 5. Loading the lubricant: the ceramic preforms with different surface textures sintered at high temperature are loaded with the solid lubricant WS ₂ by hydrothermal, the hydrothermal reaction is raised from room temperature to 200°C, the heating rate is 3°C/min, and then the temperature is maintained. 24 hours.

beneficial effect

A method for 3D printing textured self-lubricating ceramic materials proposed by the present invention uses drawing software to draw three-dimensional model diagrams of different surface textures, and then uses 3D printing technology to print out ceramic precursors with surface textures. The characteristics of ceramic materials are that after high-temperature sintering, a lubricant is mounted on the surface to achieve a synergistic effect of structure and lubrication. The geometric parameters such as the topography of the surface texture are precisely controlled by 3D printing technology, which facilitates the realization of the synergistic effect of the structure and the lubricant. The invention has flexible structure design, can be formed at one time for surface structure and material preparation, simple process operation, high repeatability, short time consumption and low cost, and is suitable for printing of ceramic materials such as Al ₂ O ₃ , ZrO ₂ and SiO ₂ . 3D printing textured self-lubricating ceramic materials for aerospace high temperature sliding sealing systems.

The beneficial effects of the present invention are as follows:

1. The surface texture can be flexibly designed, and the geometric parameters such as the shape, texture size, area density and depth-diameter ratio of the surface texture can be precisely controlled, so as to select the texture with the best lubricating effect.

2. The use of 3D printing technology can realize the integration and rapid prototyping of ceramic materials and textures. The process is simple in operation, high in repeatability, short in time, and low in cost, which can improve preparation efficiency.

3. The method is suitable for printing ceramic materials such as Al ₂ O ₃ , ZrO ₂ , SiO ₂ and the like, and has a wide range of applications. The friction and wear properties of the prepared 3D printing textured self-lubricating ceramic materials were tested. The results showed that the friction coefficient of the Al ₂ O ₃ ceramic material without 3D printing surface texture was 1.006, and the Al ₂ O ₃ ceramic material with surface texture was 1.006. The minimum friction coefficient of ceramic materials can be reduced to 0.441, a decrease of 56.16%.

Description of drawings

Figure 1: 3D printing texture design diagram of the present invention

(a) Circular petal-like densely arranged surface texture with a hemisphere diameter of 2.5 mm; (b) circular petal-like hexagonally arranged surface texture with a hemispherical diameter of 2.5 mm; (c) circular petal-shaped hexagonal arrangement with a hemispherical diameter of 5 mm The surface texture of petal-like dense arrangement; (d) the surface texture of circular petal-like hexagonal arrangement with a hemisphere diameter of 5 mm;

Figure 2: 3D printing of Al ₂ O ₃ ceramic materials with different surface textures in Example 1, Example 2, Example 3 and Example 4 of the present invention.

Figure 3: SEM image of WS ₂ with solid lubricant.

Detailed ways

The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

Example 1.

As shown in Figure 2(a), the 3D printing circular petal-like densely arranged surface textured Al ₂ O ₃ ceramic material of the present invention is shown. The friction coefficient of this material is 0.650, which is 35.39% lower than that of the material without surface texture.

Step 1: Design and draw circular petal-like densely arranged surface texture, and save it as an STL file. The size of the sample is φ24mm×6mm, the diameter of the hemisphere in the surface texture is 2.5mm, the diameter of the pit in the middle of the hemisphere is 1.25mm, and the depth is 0.6mm, which are densely arranged and distributed.

Step 2: Open the file in the slicing software, adjust the sample position to the middle of the printing platform, set the layer thickness of the printing material to 55 μm, the number of layers of the bottom plate to 5 layers, and the material selection to be Al ₂ O ₃ . After the slicing is completed, save it in U disk.

Step 3: Copy the files in the U disk to a 3D printer to print a prefab with surface texture.

Step 4: The ceramic preform is placed in a box furnace for sintering, and kept at 300°C, 600°C and 900°C for 2 hours each, at 1500°C for 3 hours, and then cooled to room temperature.

Step 5: The solid lubricant WS ₂ is mounted in a hydrothermal manner, the hydrothermal reaction is raised from room temperature to 200° C., the heating rate is 3° C./min, and then the temperature is maintained for 24 hours.

Example 2.

As shown in Fig. 2(b), the 3D printing circular petal-like densely arranged surface textured Al ₂ O ₃ ceramic material of the present invention is shown. The friction coefficient of this material is 0.411, which is 59.15% lower than that of the material without surface texture.

Step 1: Design and draw the surface texture of the circular petal-shaped hexagonal arrangement, and save it as an STL format file. The size of the sample is φ24mm×6mm, the diameter of the hemisphere in the surface texture is 2.5mm, the diameter of the pit in the middle of the hemisphere is 1.25mm, the depth is 0.6mm, and it is distributed in a hexagonal arrangement.

Step 2: Open the file in the slicing software, adjust the sample position to the middle of the printing platform, set the layer thickness of the printing material to 55 μm, the number of layers of the bottom plate to 5 layers, and the material selection to be Al ₂ O ₃ . After the slicing is completed, save it in U disk.

Step 3: Copy the files in the U disk to a 3D printer to print a prefab with surface texture.

Step 4: The ceramic preform is placed in a box furnace for sintering, and kept at 300°C, 600°C and 900°C for 2 hours each, at 1500°C for 3 hours, and then cooled to room temperature.

Step 5: The solid lubricant WS ₂ is mounted in a hydrothermal manner, the hydrothermal reaction is raised from room temperature to 200° C., the heating rate is 3° C./min, and then the temperature is maintained for 24 hours.

Example 3.

As shown in Figure 2(c), the 3D printing circular petal-like densely arranged surface textured Al ₂ O ₃ ceramic material of the present invention is shown. The friction coefficient of this material is 0.651, which is 35.29% lower than that of the material without surface texture.

Step 1: Design and draw circular petal-like densely arranged surface texture, and save it as an STL file. The size of the sample is φ24mm×6mm, the diameter of the hemisphere in the surface texture is 5mm, the diameter of the pit in the middle of the hemisphere is 2.5mm, and the depth is 0.6mm, which are densely arranged and distributed.

Step 2: Open the file in the slicing software, adjust the sample position to the middle of the printing platform, set the layer thickness of the printing material to 55 μm, the number of layers of the bottom plate to 5 layers, and the material selection to be Al ₂ O ₃ . After the slicing is completed, save it in U disk.

Step 3: Copy the files in the U disk to a 3D printer to print a prefab with surface texture.

Step 4: The ceramic preform is placed in a box furnace for sintering, and kept at 300°C, 600°C and 900°C for 2 hours each, at 1500°C for 3 hours, and then cooled to room temperature.

Step 5: The solid lubricant WS ₂ is mounted in a hydrothermal manner, the hydrothermal reaction is raised from room temperature to 200° C., the heating rate is 3° C./min, and then the temperature is maintained for 24 hours.

Example 4.

As shown in Figure 2(c), the 3D printing circular petal-like densely arranged surface textured Al ₂ O ₃ ceramic material of the present invention is shown. The friction coefficient of this material is 0.472, which is 53.08% lower than that of the material without surface texture.

Step 1: Design and draw the surface texture of the circular petal-shaped hexagonal arrangement, and save it as an STL format file. The size of the sample is φ24mm×6mm, the diameter of the hemisphere in the surface texture is 5mm, the diameter of the pit in the middle of the hemisphere is 2.5mm, and the depth is 0.6mm, which are distributed in a hexagonal arrangement.

Step 2: Open the file in the slicing software, adjust the sample position to the middle of the printing platform, set the layer thickness of the printing material to 55 μm, the number of layers of the bottom plate to 5 layers, and the material selection to be Al ₂ O ₃ . After the slicing is completed, save it in U disk.

Step 3: Copy the files in the U disk to a 3D printer to print a prefab with surface texture.

Step 4: The ceramic preform is placed in a box furnace for sintering, and kept at 300°C, 600°C and 900°C for 2 hours each, at 1500°C for 3 hours, and then cooled to room temperature.

Step 5: The solid lubricant WS ₂ is mounted in a hydrothermal manner, the hydrothermal reaction is raised from room temperature to 200° C., the heating rate is 3° C./min, and then the temperature is maintained for 24 hours.

Claims (1)

1. A method for 3D printing of a textured self-lubricating ceramic material is characterized by comprising the following steps:

step 1, designing and drawing a surface texture: designing surface textures with different geometric parameters, drawing a three-dimensional model by adopting SolidWorks drawing software, and storing the three-dimensional model as an STL format file;

step 2, computer slicing treatment: opening the STL format file formed in the step 1 in slicing software, adjusting the position and the scaling size of the three-dimensional model on a platform, setting the layer thickness of a printing material to be 55 microns and the layer number of a bottom plate to be 5 layers, and obtaining a sliced file;

step 3, 3D printing: copying the cut file to a 3D printer, and printing ceramic preforms with different surface textures by using ceramic slurry;

and 4, high-temperature sintering: sintering the obtained ceramic preform in a box furnace, keeping the temperature for 2 hours when the temperature is raised to 300 ℃, 600 ℃ and 900 ℃, keeping the temperature for 3 hours when the temperature is raised to 1500 ℃, and then cooling to room temperature;

and step 5, carrying a lubricant: carrying a solid lubricant WS on a high-temperature sintered ceramic preform with different surface textures by hydrothermal treatment₂The hydrothermal reaction is heated from room temperature to 200 ℃ at a heating rate of 3 ℃/min and then is kept for 24 hours.

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