Preparation method of 3D printing oil-containing ceramic lubricating composite material with porous structure

Abstract

The present application relates to the technical field of self-lubricating ceramics, and particularly relates to a preparation method of 3D printing oil-containing ceramic lubricating composite material with porous structure. The preparation method provided by the present application comprises the following steps: mixing mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator and defoaming agent to obtain 3D printing ceramic slurry of mesoporous silica microspheres; performing light curing 3D printing treatment on the 3D printing ceramic slurry of mesoporous silica microspheres to obtain a ceramic green body; sequentially performing debinding and sintering treatment on the ceramic green body to obtain 3D printing ceramic material with porous structure; and performing vacuum oil immersion treatment on the 3D printing ceramic material with porous structure to obtain the 3D printing oil-containing ceramic lubricating composite material with porous structure. The preparation method realizes fine regulation and control of the internal pore structure of the self-lubricating porous ceramic composite material and improvement of the oil storage capacity, and the method is simple and effective.

Description

Technical Field

[0001] This invention relates to the field of self-lubricating structural ceramics technology, and more particularly to a method for preparing a 3D-printed ceramic lubricating composite material with a porous structure. Background Technology

[0002] With the development of science and technology, for parts operating under extreme conditions such as high speed, ultra-high load, high strength, and high reliability, friction and wear between moving pairs can directly lead to component failure, resulting in uncontrollable consequences. Ceramic lubricating composite materials have advantages such as a wide operating temperature range, low friction and wear, anti-pollution, high load-bearing capacity, and high chemical stability, enabling effective lubrication under special conditions such as ultra-high temperature and strong corrosion. However, due to the inherent structural characteristics of ceramic materials, they possess significant brittleness and low toughness, and exhibit a high coefficient of friction and wear rate under friction without a medium, which limits their engineering applications. Therefore, it is necessary to modify ceramic materials to imbue the sliding surfaces with lubricating properties, thereby preparing ceramic-based self-lubricating composite materials to meet their application requirements in the field of high-temperature self-lubrication. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a 3D-printed ceramic-containing lubricating composite material with a porous structure. The 3D-printed ceramic-containing lubricating composite material with a porous structure prepared by the method can meet the application requirements in the field of high-temperature self-lubrication.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing a 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure, comprising the following steps:

[0006] Mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator and defoamer are mixed to obtain a 3D printing ceramic slurry for mesoporous silica microspheres;

[0007] The 3D printing ceramic slurry of the mesoporous silica microspheres was subjected to photopolymerization 3D printing to obtain a ceramic green body;

[0008] The ceramic blank is sequentially degreased and sintered to obtain a 3D printed ceramic material with a porous structure.

[0009] The porous 3D printed ceramic material is subjected to vacuum oil impregnation to obtain the porous 3D printed oil-impregnated ceramic lubricating composite material.

[0010] Preferably, the mesoporous silica microspheres have a mesopore size of 2–20 nm and a particle size of 30 nm–5 μm.

[0011] The particle size of the inorganic ceramic powder is 50 nm to 100 μm.

[0012] Preferably, the inorganic ceramic powder includes silicon dioxide ceramic powder, aluminum oxide ceramic powder, zirconium dioxide ceramic powder, silicon carbide ceramic powder, silicon nitride ceramic powder, or aluminum nitride ceramic powder.

[0013] Preferably, the photosensitive resin is a free radical type photosensitive resin and / or a cationic type photosensitive resin;

[0014] The raw materials for preparing the photosensitive resin include photosensitive resin monomers or photosensitive resin prepolymers;

[0015] The photoinitiator includes radical photoinitiators and / or cationic photoinitiators.

[0016] Preferably, the photosensitive resin includes one or more of polyurethane acrylate, epoxy acrylate, polyester acrylate, epoxy resin, vinyl ether resin, monofunctional photosensitive resin monomer, difunctional photosensitive resin monomer, and trifunctional or higher photosensitive resin monomer.

[0017] Preferably, the mass ratio of the mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator and defoamer is (1-20):(25-45):(35-74):(0.1-3):(0.1-1).

[0018] Preferably, the mixing includes a homogenization process and a three-roll milling process performed sequentially;

[0019] The mixing process includes: mixing photosensitive resin, photoinitiator and defoamer to obtain 3D printing resin;

[0020] Mesoporous silica microspheres and inorganic ceramic powder were divided into three parts, and then added to the 3D printing resin in sequence for homogenization treatment and three-roll milling treatment.

[0021] The homogenization process is carried out at a rotation speed of 300–1000 r / min for 1–5 min, with a vacuum degree of 0–1.3 kPa.

[0022] The three-roll mill used in the three-roll milling process has a roller speed of 1 to 500 r / min, and the gap between adjacent rollers decreases from 500 μm to the larger value of the particle size of the mesoporous silica and inorganic ceramic powder.

[0023] Preferably, the thickness of the printed layer in the photopolymerization 3D printing process is 10–200 μm, the exposure time is 0.5–30 s, and the required energy density is 2–75 mW / cm³. 2 .

[0024] Preferably, the degreasing and sintering treatment is performed by a stepped heating process;

[0025] The degreasing process is as follows: the temperature is increased from room temperature to 600°C at a heating rate of 0.1 to 2°C / min, and the holding time is 1 hour.

[0026] The sintering process is as follows: the temperature is increased from 600℃ to 1000℃ at a heating rate of 1-10℃ / min and held for 60 min, and finally increased to 1200-1500℃ at a heating rate of 1-10℃ / min and held for 120 min, followed by cooling.

[0027] Preferably, the lubricating oil used in the vacuum impregnation treatment is one or more of hydrocarbon lubricating oil, ester lubricating oil, mineral base oil and polyether.

[0028] This invention provides a method for preparing a 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure, comprising the following steps: mixing mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator, and defoamer to obtain a 3D-printed ceramic slurry of mesoporous silica microspheres; subjecting the 3D-printed ceramic slurry of mesoporous silica microspheres to photocuring 3D printing to obtain a ceramic green body; subjecting the ceramic green body to degreasing and sintering treatments sequentially to obtain a 3D-printed ceramic material with a porous structure; and subjecting the 3D-printed ceramic material with a porous structure to vacuum oil impregnation treatment to obtain the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure. This invention combines mesoporous silica microspheres as a raw material with 3D printing technology to achieve precise control over the microstructure and pore structure of ceramic materials, enabling the preparation of fine ceramic products with complex and diverse shapes. This method is of great significance for the microstructure and functional control of 3D-printed porous ceramics. Furthermore, impregnating porous ceramics with solid lubricants can achieve the purpose of anti-wear and friction reduction, and has broad application prospects in aerospace, microelectronics, nuclear energy and other technical fields. In addition to the inherent advantages of ceramic materials such as high temperature resistance, corrosion resistance and high load-bearing capacity, the 3D printed oil-impregnated ceramic lubricating composite material with porous structure prepared by this invention also has the advantages of light weight and high strength.

[0029] Therefore, compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention combines 3D printing technology with mesoporous silica microspheres and vacuum oil impregnation to prepare 3D-printed self-lubricating ceramic composite materials with porous structures. This achieves precise control over the internal pore structure of the self-lubricating porous ceramic composite material and increases its oil storage capacity. The method is simple and effective. Meanwhile, ceramic materials are hard and brittle, making their molding and processing much more difficult than metals and polymers, especially for ceramic parts with complex shapes or structures, such as those with curved outer surfaces, conformal internal channels, or fine structures like small or deep pores. Traditional molding and processing methods are no longer sufficient. This invention, using photopolymerization 3D printing technology, offers unparalleled advantages for preparing ceramic parts with complex shapes or structures. It is of great significance for the microstructure and functional control of 3D-printed porous ceramics and can effectively expand the application of 3D printing technology in the field of tribology. Attached Figure Description

[0031] Figure 1 This is a TEM image of the mesoporous silica microspheres described in Example 1;

[0032] Figure 2 The image shows a cross-section of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure as described in Example 1.

[0033] Figure 3 This is a SEM image of the cross-section of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure described in Example 3;

[0034] Figure 4 This is an optical image of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure described in Example 3;

[0035] Figure 5 Thermogravimetric curve of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure as described in Example 1;

[0036] Figure 6 The rheological curve of the ceramic slurry described in Example 1;

[0037] Figure 7 These are comparison images of the ceramic slurry described in Example 3 before and after standing for 15 days.

[0038] Figure 8 The friction coefficient curves of the 3D printed oil-impregnated ceramic materials with porous structures described in Comparative Example 1 and Examples 2-3 are obtained from friction tests at room temperature.

[0039] Figure 9 The images shown are metallographic microscope images and high-magnification SEM images of the wear marks on the 3D printed ceramic material with a porous structure described in Example 2 after a friction experiment.

[0040] Figure 10The images shown are physical representations of the 3D-printed oil-impregnated ceramic materials with porous structures described in Examples 2 and 4, where (a) and (b) are from Example 2, and (c) and (d) are from Example 4. Detailed Implementation

[0041] This invention provides a method for preparing a 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure, comprising the following steps:

[0042] Mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator and defoamer are mixed to obtain a 3D printing ceramic slurry for mesoporous silica microspheres;

[0043] The 3D printing ceramic slurry of the mesoporous silica microspheres was subjected to photopolymerization 3D printing to obtain a ceramic green body;

[0044] The ceramic blank is sequentially degreased and sintered to obtain a 3D printed ceramic material with a porous structure.

[0045] The porous 3D printed ceramic material is subjected to vacuum oil impregnation to obtain the porous 3D printed oil-impregnated ceramic lubricating composite material.

[0046] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0047] This invention mixes mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator and defoamer to obtain a 3D printing ceramic slurry for mesoporous silica microspheres.

[0048] In this invention, the mesoporous silica microspheres preferably have a mesopore diameter of 2 to 20 nm and a particle size of 30 nm to 5 μm.

[0049] In this invention, the particle size of the inorganic ceramic powder is preferably 50 nm to 100 μm, more preferably 10 to 100 μm. In this invention, the inorganic ceramic powder includes silicon dioxide ceramic powder, aluminum oxide ceramic powder, zirconium dioxide ceramic powder, silicon carbide ceramic powder, silicon nitride ceramic powder, or aluminum nitride ceramic powder.

[0050] In this invention, the photosensitive resin is preferably a free radical photosensitive resin and / or a cationic photosensitive resin; the raw materials for preparing the photosensitive resin preferably include photosensitive resin monomers or photosensitive resin prepolymers; more preferably, they include one or more of polyurethane acrylates, epoxy acrylates, polyester acrylates, epoxy resins, vinyl ether resins, monofunctional photosensitive resin monomers, bifunctional photosensitive resin monomers, and trifunctional or higher photosensitive resin monomers; the polyurethane acrylate preferably includes Easepi 864, AgiSyn 248, and Easepi U600; the epoxy acrylate preferably includes AgiSyn 9750 and AgiSyn 1030; the polyester acrylate preferably includes AgiSyn 730; the epoxy resin preferably includes Easepi2021P; the vinyl ether resin preferably includes DVE-3; the monofunctional photosensitive resin monomer preferably includes HEMA, ACMO, IBOA, CTFA, PHEA; the bifunctional photosensitive resin monomer preferably includes HDDA, PEG(400)DA, NPG2PODA, DPGDA; the trifunctional or higher photosensitive resin monomer preferably includes TMPTA, TMP3EOTA, PETA, DPHA; when the photosensitive resin is two or more of the above-mentioned specific selections, the present invention does not have any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio.

[0051] In this invention, the photoinitiator preferably includes a radical photoinitiator and / or a cationic photoinitiator; the radical photoinitiator preferably includes Omnirad TPO or Omnirad 819; the cationic photoinitiator preferably includes Easepi 784.

[0052] In this invention, the defoamer preferably includes Deqian 1622 and / or BYK052N. When the defoamer is one of the two specifically selected above, this invention does not impose any special limitation on the ratio of the specific substances, and they can be mixed in any ratio.

[0053] In this invention, the preferred mass ratio of the mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator, and defoamer is (1-20):(25-45):(35-74):(0.1-3):(0.1-1), more preferably (5-20):(30-45):(35-65):(0.2-2):(0.1-0.8), and most preferably (10-20):(30-40):(40-60):(0.3-1):(0.1-0.6).

[0054] In this invention, the mixing preferably includes a homogenization process and a three-roll milling process performed sequentially; the mixing preferably includes: mixing photosensitive resin, photoinitiator and defoamer to obtain 3D printing resin; dividing mesoporous silica microspheres and inorganic ceramic powder into three parts, adding them sequentially to the 3D printing resin for homogenization, and then performing a three-roll milling process.

[0055] In this invention, the rotational speed of the homogenization process is preferably 300–1000 r / min, more preferably 500–800 r / min, and most preferably 600–700 r / min; the time is preferably 1–5 min, more preferably 2–4 min, and most preferably 3 min. The three-roll milling process preferably uses a three-roll mill, and the roller rotational speed of the three-roll mill is preferably 1–500 r / min, more preferably 100–400 r / min, and most preferably 200–300 r / min. The gap between adjacent rollers preferably decreases from 500 μm to the larger of the particle sizes of the mesoporous silica and inorganic ceramic powder. In this invention, the process of passing through the roller mill is preferably such that the slurry obtained after ball milling passes through the gap between adjacent rollers, utilizing the shearing action between the rollers to disperse the agglomerated powder.

[0056] After obtaining the 3D printing ceramic slurry of mesoporous silica microspheres, the present invention performs photopolymerization 3D printing treatment on the 3D printing ceramic slurry of the mesoporous silica microspheres to obtain a ceramic blank.

[0057] Before performing the photopolymerization 3D printing process, the present invention preferably includes defoaming. The present invention does not impose any special limitations on the defoaming process, and any process known to those skilled in the art can be used.

[0058] In this invention, the photopolymerization 3D printing process is preferably performed using digital laser technology (DLP). The thickness of the printed layer is preferably 10–200 μm, more preferably 20–150 μm, and most preferably 30–100 μm; the exposure time is preferably 0.5–30 s, more preferably 1–20 s, and most preferably 3–10 s; the required energy density is preferably 2–75 mW / cm³. 2 More preferably, it is 10–60 mW / cm 2 The optimal value is 20–40 mW / cm². 2 .

[0059] After the photopolymerization 3D printing process is completed, the present invention preferably includes cleaning, and the cleaning agent used is preferably isopropanol or ethanol; the present invention does not have any special limitations on the cleaning process, and any process known to those skilled in the art can be used to ensure that excess resin on the surface can be removed.

[0060] After obtaining the ceramic blank, the present invention performs degreasing and sintering treatments on the ceramic blank in sequence to obtain a 3D printed ceramic material with a porous structure.

[0061] In this invention, the degreasing process is preferably: heating from room temperature to 600°C at a heating rate of 0.1–2°C / min, and holding for 1 hour; the sintering process is preferably: heating from 600°C to 1000°C at a heating rate of 1–10°C / min, holding for 60 minutes, and finally heating to 1200–1500°C at a heating rate of 1–10°C / min, holding for 120 minutes, and then cooling; the cooling is preferably furnace cooling.

[0062] After obtaining a 3D printed ceramic material with a porous structure, the present invention performs a vacuum oil impregnation treatment on the 3D printed ceramic material with a porous structure to obtain the 3D printed oil-impregnated ceramic lubricating composite material with a porous structure.

[0063] In this invention, the lubricating oil used in the vacuum immersion oil treatment is preferably one or more of hydrocarbon lubricating oil, ester lubricating oil, mineral base oil, and polyether; the hydrocarbon lubricating oil preferably includes one or more of polyalphaolefin, polybutene, and alkylbenzene; the ester lubricating oil preferably includes polyol esters and / or diesters; the mineral base oil preferably includes liquid paraffin lubricating oil; the polyether preferably includes one or more of perfluoropolyether and / or PAG polyether; and the perfluoropolyether lubricating oil preferably includes Fomblin-YR1800 lubricating oil. When the lubricating oil is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio.

[0064] In this invention, the vacuum oil impregnation process is preferably carried out by placing the 3D printed ceramic material with a porous structure in a round-bottom flask, performing vacuum treatment for 1 hour, and then injecting lubricating oil into the round-bottom flask through a separating funnel for vacuum oil impregnation treatment, and continuing to maintain the vacuum environment for 4 hours.

[0065] After the vacuum oil impregnation process is completed, the present invention preferably includes wiping and cleaning with petroleum ether to remove excess lubricating oil, followed by drying; the drying temperature is preferably 60°C.

[0066] The following detailed description of the preparation method of the 3D-printed oil-containing ceramic lubricating composite material with a porous structure provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0067] Example 1

[0068] 55g of photosensitive resin (HDDA:PEGDA:EasepiU600 = 15:65:20 (mass ratio)), 0.5g of photoinitiator (Omnirad TPO) and 0.5g of defoamer (BYK052N) were mixed to obtain 3D printing resin.

[0069] 15g of mesoporous silica nanospheres (mesopore size 2.3nm, particle size 50nm) and 30g of inorganic ceramic powder (particle size 10μm, silica ceramic powder) were divided into three portions and added to the 3D printing resin in sequence for homogenization treatment (rotation speed 800r / min, time 5min). Then, three-roll milling treatment was performed (the slurry after ball milling was passed through the gap between adjacent rollers in the three-roll mill, the gap gradually decreased from 500μm to 10μm, and the roller rotation speed was 100r / min) to obtain the 3D printing ceramic slurry of mesoporous silica nanospheres.

[0070] The mesoporous silica microspheres were placed in the ceramic slurry container of a 3D printer, and digital laser printing was performed according to the preset printing parameters. The printed layer thickness was 50 μm, the exposure time was 10 s, and the required energy density was 35 mW / cm³. 2 After printing, excess resin on the surface is removed by acetone cleaning to obtain 3D printing photosensitive resin.

[0071] The 3D printing photosensitive resin was degreased and sintered. The degreasing process involved heating to 600°C at a rate of 1°C / min and holding for 1 hour. The sintering process involved heating from 600°C to 1000°C at a rate of 10°C / min and holding for 60 minutes. Finally, the temperature was increased to 1400°C at a rate of 10°C / min and held for 120 minutes. The resin was then cooled to room temperature in the furnace to obtain a 3D printed ceramic material with a porous structure.

[0072] The porous 3D-printed ceramic material was placed in a round-bottom flask and subjected to vacuum treatment for 1 hour. Then, Fomblin-YR1800 lubricating oil was injected into the flask through a separatory funnel for vacuum oil impregnation treatment. The vacuum environment was maintained for another 4 hours. The ceramic material after vacuum oil impregnation treatment was wiped and cleaned with petroleum ether to remove excess lubricating oil. Then, it was placed in an oven at 60°C to dry, thus obtaining the porous 3D-printed oil-impregnated ceramic lubricating composite material.

[0073] Figure 1 The image shown is a TEM image of the mesoporous silica microspheres. Figure 1 It can be seen that the mesoporous silica has good dispersibility, and the particles exhibit a regular spherical morphology with a particle size of 50 nm and uniform particle size.

[0074] Figure 2 This is a SEM image of the cross-section of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure. Figure 2 It can be seen that the mesoporous silica nanoparticles and ceramic powder are evenly dispersed and aggregated with each other, and no obvious large cracks were observed.

[0075] Example 2

[0076] 65g of photosensitive resin (HDDA:PEGDA:EasepiU600 = 15:65:20 (mass ratio)), 0.5g of photoinitiator (Omnirad TPO) and 0.5g of defoamer (BYK052N) were mixed to obtain 3D printing resin.

[0077] 10g of mesoporous silica nanospheres (mesopore size 2.3nm, particle size 50nm) and 25g of inorganic ceramic powder (particle size 10μm, silica ceramic powder) were divided into three portions and added to the 3D printing resin in sequence for homogenization treatment (rotation speed 800r / min, time 5min). Then, three-roll milling treatment was performed (the slurry after ball milling was passed through the gap between adjacent rollers in the three-roll mill, the gap gradually decreased from 500μm to 10μm, and the roller rotation speed was 100r / min) to obtain the 3D printing ceramic slurry of mesoporous silica nanospheres.

[0078] The mesoporous silica microspheres were placed in the ceramic slurry container of a 3D printer, and digital laser printing was performed according to the preset printing parameters. The printed layer thickness was 40 μm, the exposure time was 15 s, and the required energy density was 45 mW / cm³. 2 After printing, excess resin on the surface is removed by acetone cleaning to obtain 3D printing photosensitive resin.

[0079] The 3D printing photosensitive resin is subjected to debinding and sintering treatment. The debinding and sintering treatment process is as follows: the temperature is increased to 150℃ at a rate of 1℃ / min and held for 30min, then increased to 325℃ at the same rate and held for 60min, then increased to 420℃ at a rate of 0.5℃ / min and held for 60min, then increased to 1000℃ at a rate of 3℃ / min and held for 60min, then increased to 1400℃ at the same rate and held for 120min, and then cooled to room temperature in the furnace to obtain a 3D printed ceramic material with a porous structure.

[0080] The porous 3D-printed ceramic material was placed in a round-bottom flask and subjected to vacuum treatment for 1 hour. Then, Fomblin-YR1800 lubricating oil was injected into the flask through a separatory funnel for vacuum oil impregnation treatment. The vacuum environment was maintained for another 4 hours. The ceramic material after vacuum oil impregnation treatment was wiped and cleaned with petroleum ether to remove excess lubricating oil. Then, it was placed in an oven at 60°C to dry, thus obtaining the porous 3D-printed oil-impregnated ceramic lubricating composite material.

[0081] Figure 9 The images shown are metallographic microscope images and high-magnification SEM images of the wear marks on the porous 3D-printed ceramic material described in Example 2 after a friction experiment. Figure 9 As can be seen, after the friction test, the ceramic surface showed a certain degree of wear, with some shallow pits.

[0082] Example 3

[0083] 65g of photosensitive resin (HDDA:PEGDA:EasepiU600 = 15:65:20 (mass ratio)), 0.5g of photoinitiator (Omnirad TPO) and 0.5g of defoamer (BYK052N) were mixed to obtain 3D printing resin.

[0084] Five g of mesoporous silica nanospheres (mesoporous pore size of 2.3 nm, particle size of 50 nm) and three g of inorganic ceramic powder (particle size of 10 μm, type of silica ceramic powder) were divided into three portions. They were added to the 3D printing resin in sequence for homogenization treatment (rotation speed of 800 r / min, time of 5 min). Then, they were subjected to three-roll milling treatment (the slurry after ball milling was passed through the gap between adjacent rollers in the three-roll mill, the gap gradually decreased from 500 μm to 10 μm, and the roller rotation speed was 100 r / min) to obtain the 3D printing ceramic slurry of mesoporous silica nanospheres.

[0085] The mesoporous silica microspheres were placed in the ceramic slurry container of a 3D printer, and digital laser printing was performed according to the preset printing parameters. The printed layer thickness was 100 μm, the exposure time was 30 s, and the required energy density was 75 mW / cm³. 2 After printing, excess resin on the surface is removed by acetone cleaning to obtain 3D printing photosensitive resin.

[0086] The 3D printing photosensitive resin is subjected to debinding and sintering treatment. The debinding and sintering treatment process is as follows: the temperature is increased to 150℃ at a rate of 1℃ / min and held for 30min, then increased to 325℃ at the same rate and held for 60min, then increased to 420℃ at a rate of 0.5℃ / min and held for 60min, then increased to 1000℃ at a rate of 3℃ / min and held for 60min, then increased to 1400℃ at the same rate and held for 120min, and then cooled to room temperature in the furnace to obtain a 3D printed ceramic material with a porous structure.

[0087] The porous 3D-printed ceramic material was placed in a round-bottom flask and subjected to vacuum treatment for 1 hour. Then, Fomblin-YR1800 lubricating oil (a perfluoropolyether lubricating oil) was injected into the flask through a separatory funnel for vacuum impregnation. The vacuum environment was maintained for another 4 hours. The vacuum-impregnated ceramic material was then wiped clean with petroleum ether to remove excess lubricating oil. Finally, it was placed in an oven at 60°C to dry, thus obtaining the porous 3D-printed oil-impregnated ceramic lubricating composite material.

[0088] Figure 3 This is a SEM image of the cross-section of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure. Figure 3 It can be seen that the mesoporous silica nanoparticles are uniformly dispersed with the ceramic powder, and the particles aggregate with each other. No obvious large cracks were observed. By increasing the amount of mesoporous silica nanoparticles added, the internal pore defects of the porous ceramic are significantly reduced, which is beneficial to the improvement of the mechanical properties of the material.

[0089] Figure 4 The image shown is a metallographic microscope image of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure. Figure 4 It can be seen that the surface of the 3D printed ceramic material with porous structure is smooth and there are no obvious cracks.

[0090] Figure 5 The thermogravimetric curve of the 3D-printed oil-impregnated ceramic lubricating composite material with a porous structure is given by... Figure 5 It can be seen that the mass loss of the sample accounts for about 32.6% of the total mass within the temperature range of 200–700℃. This temperature range corresponds to the thermal decomposition range of lubricating oil, indicating that the prepared porous ceramic absorbs about 32.6% of the lubricating oil after adsorption. By precisely controlling the pore structure of 3D printed porous ceramics, it is possible to achieve high lubricating oil storage capacity of porous ceramics and to design and prepare various fine and complex shapes of porous ceramics.

[0091] Example 4

[0092] 65g of photosensitive resin (ACMO:DPGDA:TMPTA:Easepi U600 = 27:36:27:1 (mass ratio)), 0.5g of photoinitiator (Omnirad TPO) and 0.5g of defoamer (BYK052N) were mixed to obtain 3D printing resin.

[0093] Eight g of mesoporous silica nanospheres (mesoporous pore size of 2.4 nm, particle size of 50 nm) and 22 g of inorganic ceramic powder (particle size of 10 μm, type of silica ceramic powder) were divided into three portions. They were added to the 3D printing resin in sequence for homogenization treatment (rotation speed of 800 r / min, time of 5 min). Then, they were subjected to three-roll milling treatment (the slurry after ball milling was passed through the gap between adjacent rollers in the three-roll mill, the gap gradually decreased from 500 μm to 10 μm, and the roller rotation speed was 100 r / min) to obtain the 3D printing ceramic slurry of mesoporous silica nanospheres.

[0094] The mesoporous silica microspheres were placed in the ceramic slurry container of a 3D printer, and digital laser printing was performed according to the preset printing parameters. The printed layer thickness was 80 μm, the exposure time was 20 s, and the required energy density was 55 mW / cm³. 2 After printing, the excess resin on the surface is removed by cleaning with acetone to obtain 3D printing photosensitive resin.

[0095] The 3D printing photosensitive resin is subjected to debinding and sintering treatment. The debinding and sintering treatment process is as follows: the temperature is increased to 150℃ at a rate of 1℃ / min and held for 30min, then increased to 325℃ at the same rate and held for 60min, then increased to 420℃ at a rate of 0.5℃ / min and held for 60min, then increased to 1000℃ at a rate of 3℃ / min and held for 60min, then increased to 1200℃ at the same rate and held for 120min, and then cooled to room temperature in the furnace to obtain a 3D printed ceramic material with a porous structure.

[0096] The porous 3D-printed ceramic material was placed in a round-bottom flask and subjected to vacuum treatment for 1 hour. Then, liquid paraffin lubricating oil was injected into the flask through a separatory funnel for vacuum oil impregnation treatment. The vacuum environment was maintained for another 4 hours. The ceramic material after vacuum oil impregnation treatment was wiped and cleaned with petroleum ether to remove excess lubricating oil. Then, it was placed in an oven at 60°C to dry, thus obtaining the porous 3D-printed oil-impregnated ceramic lubricating composite material.

[0097] Figure 6 The rheological curve of the ceramic slurry is given by... Figure 6It can be seen that the viscosity of the slurry decreased significantly with the increase of shear stress, indicating that the slurry has good dispersion stability and can be stored for a long time.

[0098] Figure 7 These are comparative images of the ceramic slurry before and after 15 days of standing. Figure 7 It can be seen that after 15 days of standing, the ceramic slurry did not undergo significant sedimentation and remained in a uniformly dispersed state. Through the fine control of the pore structure of 3D printed porous ceramics, the high lubricating oil storage capacity of porous ceramics can be achieved, and the design and preparation of various fine and complex shapes of porous ceramics can be realized.

[0099] Figure 10 These are physical images of the 3D-printed oil-impregnated ceramic materials with porous structures described in Examples 2 and 4, where (a) and (b) are from Example 2, and (c) and (d) are from Example 4; Figure 10 It can be seen that the sample surface is relatively smooth and flat, without obvious cracks and pores, and the overall morphology of the sample is regular. Porous ceramics can be prepared within a wide range of mesoporous silica addition amounts.

[0100] Comparative Example 1

[0101] Inorganic ceramic powder (particle size 10μm, type: silica), photosensitive resin (type: ACMO:DPGDA:TMPTA:Easepi U600 = 27:36:27:1 (mass ratio)), photoinitiator (type: Omnirad TPO) and defoamer (type: BYK052N) were mixed and stirred evenly by rotation. Then, the mixture was subjected to ball milling (speed 300 r / min, time 4 h) and roller press treatment (the ball-milled slurry was passed through the gap between adjacent rollers in a three-roll mill, the gap gradually decreasing from 500 μm to 1 μm, the roller speed 100 r / min) to obtain ceramic slurry.

[0102] The ceramic slurry was placed in the ceramic slurry container of the 3D printer, and digital laser printing was performed according to the preset printing parameters. The printed layer thickness was 50 μm, the exposure time was 10 s, and the required energy density was 25 mW / cm³. 2 After printing, the excess resin on the surface is removed by cleaning with acetone to obtain 3D printing photosensitive resin.

[0103] The 3D printing photosensitive resin is subjected to debinding and sintering treatment. The debinding and sintering treatment process is as follows: the temperature is increased to 150℃ at a rate of 1℃ / min and held for 30min, then increased to 325℃ at the same rate and held for 60min, then increased to 420℃ at a rate of 0.5℃ / min and held for 60min, then increased to 1000℃ at a rate of 3℃ / min and held for 60min, then increased to 1200℃ at the same rate and held for 120min, and then cooled to room temperature in the furnace to obtain a 3D printed ceramic material with a porous structure.

[0104] The porous 3D printed ceramic material was placed in a round-bottom flask and vacuumed for 1 hour. Then, Fomblin-YR1800 lubricating oil was injected into the flask through a separatory funnel for vacuum impregnation. The vacuum environment was maintained for another 4 hours. The vacuum-impregnated ceramic material was then wiped clean with petroleum ether to remove excess lubricating oil. Finally, it was placed in an oven at 60°C to dry, thus obtaining the porous 3D printed oil-containing ceramic lubricating composite material.

[0105] Frictional performance tests were conducted on the porous 3D-printed oil-impregnated ceramic lubricating composite material and the porous 3D-printed oil-impregnated ceramic lubricating composite materials obtained in Examples 2 and 3 (test conditions: applied load of 5N, reciprocating frequency of 2Hz). The test results were as follows: Under the same test conditions, the porous 3D-printed oil-impregnated ceramic lubricating composite material prepared in Comparative Example 1 had a lower oil storage capacity and a friction coefficient as high as 0.75 because it did not contain mesoporous silica nanoparticles. In contrast, the porous 3D-printed oil-impregnated ceramic lubricating composite materials prepared in Examples 2 and 3D-printed oil-impregnated ceramic lubricating composite materials contained oil-impregnated mesoporous silica nanoparticles, resulting in a higher oil storage capacity and corresponding friction coefficients of 0.35 and 0.15, respectively.

[0106] Comparative Example 2

[0107] Mesoporous silica nanoparticles (mesopore size 2.3 nm, particle size 50 nm), photosensitive resin (ACMO:DPGDA:TMPTA:Easepi U600 = 27:36:27:1 (mass ratio)), photoinitiator (Omnirad TPO), and defoamer (BYK052N) were mixed and stirred evenly by rotation. Then, the mixture was subjected to ball milling (300 r / min for 4 h) and roller press treatment (the ball-milled slurry was passed through the gap between adjacent rollers in a three-roll mill, with the gap gradually decreasing from 500 μm to 1 μm, and the roller speed was 100 r / min) to obtain ceramic slurry.

[0108] The ceramic slurry was placed in the ceramic slurry container of the 3D printer, and digital laser printing was performed according to the preset printing parameters. The printed layer thickness was 50 μm, the exposure time was 10 s, and the required energy density was 25 mW / cm³. 2 After printing, excess resin on the surface is removed by acetone cleaning to obtain 3D printing photosensitive resin.

[0109] The 3D printing photosensitive resin is subjected to debinding and sintering treatment. The debinding and sintering treatment process is as follows: the temperature is increased to 150℃ at a rate of 1℃ / min and held for 30min, then increased to 325℃ at the same rate and held for 60min, then increased to 420℃ at a rate of 0.5℃ / min and held for 60min, then increased to 1000℃ at a rate of 3℃ / min and held for 60min, then increased to 1200℃ at the same rate and held for 120min, and then cooled to room temperature in the furnace to obtain a 3D printed ceramic material with a porous structure.

[0110] The porous 3D-printed ceramic material was placed in a round-bottom flask and subjected to vacuum treatment for 1 hour. Then, Fomblin-YR1800 lubricating oil was injected into the flask through a separatory funnel for vacuum oil impregnation treatment. The vacuum environment was maintained for another 4 hours. The ceramic material after vacuum oil impregnation treatment was wiped and cleaned with petroleum ether to remove excess lubricating oil. Then, it was placed in an oven at 60°C to dry, thus obtaining the porous 3D-printed oil-impregnated ceramic lubricating composite material.

[0111] Test case

[0112] Friction test:

[0113] Friction tests were conducted on the porous oil-impregnated ceramic materials prepared in Examples 1-4 and Comparative Examples 1-2. The friction test conditions were: load of 5N, 10N, and 15N; frequency of 2Hz; diameter of the paired steel ball of 6mm; and the friction coefficient was repeated at least three times, with the average value taken. Figure 8 The friction coefficient curves of the 3D-printed oil-impregnated ceramic materials with porous structures described in Comparative Example 1 and Examples 2-3 are shown in Table 1.

[0114] Table 1. Friction test results of 3D-printed ceramic materials with porous structures prepared in Examples 1-4 and Comparative Examples 1-2.

[0115]

[0116]

[0117] As shown in Table 1, the 3D printed oil-impregnated ceramic material with a porous structure prepared by the preparation method of the present invention has good self-lubricating properties.

[0118] Oil content and oil retention rate test:

[0119] The oil content retention of the porous 3D-printed oil-impregnated ceramic materials prepared in Examples 1-4 was tested. The test method was as follows: the mass difference before and after centrifugation was measured using a high-speed centrifuge at a speed of 3000 r / min for 30 min. The sample mass was weighed and the change in oil content was calculated. The oil content of the self-lubricating material can be calculated using Equation 1.

[0120]

[0121] Where, m Oil m is the weight of the lubricating oil. Toll The total mass of the sample;

[0122] The oil retention rate of the sample can be calculated using Equation 2:

[0123]

[0124] Where, m before m is the mass of the sample before centrifugation and oil removal. after The mass of the sample after centrifugation and oil removal;

[0125] The test results are shown in Table 2:

[0126] Table 2. Oil content and oil retention rate of the porous 3D printed oil-impregnated ceramic materials prepared in Examples 1-4

[0127] Oil content (%) Oil retention rate (%) Example 1 18.7 100 Example 2 12.5 100 Example 3 32.6 100 Example 4 27.5 100

[0128] As shown in Table 2, the 3D printed oil-impregnated ceramic material with a porous structure prepared by the preparation method of the present invention has good oil content and oil retention rate.

[0129] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a 3D printed oil-containing ceramic lubricating composite material having a porous structure, characterized by, Consists of the following steps: Mixing mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator and defoaming agent to obtain 3D printing ceramic slurry of mesoporous silica microspheres; the inorganic ceramic powder is silica ceramic powder; the mass ratio of mesoporous silica microspheres, inorganic ceramic powder, photosensitive resin, photoinitiator and defoaming agent is 5:30:65:0.5:0.5; The 3D printing ceramic slurry of mesoporous silica microspheres is subjected to photocuring 3D printing treatment to obtain a ceramic body; The ceramic body is sequentially subjected to debinding and sintering treatment to obtain a 3D printed ceramic material with a porous structure; The 3D printed ceramic material with a porous structure is subjected to vacuum oil immersion treatment to obtain the 3D printed oil-containing ceramic lubricating composite material with a porous structure; The debinding and sintering process is as follows: 1℃ / min to 150℃ for 30min, continue to increase the temperature at the same rate to 325℃ for 60min, then increase the temperature at the rate of 0.5℃ / min to 420℃ for 60min, then increase the temperature at the rate of 3℃ / min to 1000℃ for 60min, then increase the temperature at the same rate to 1400℃ for 120min, and then cool down to room temperature in the furnace.

2. The production method according to claim 1, wherein The mesoporous silica microspheres have a mesoporous pore size of 2-20nm and a particle size of 30nm-5μm; The inorganic ceramic powder has a particle size of 50nm-100μm.

3. The production method according to claim 1, wherein The photosensitive resin is a free radical type photosensitive resin and / or a cationic type photosensitive resin; The raw materials for preparing the photosensitive resin include photosensitive resin monomers or photosensitive resin prepolymers; The photoinitiator includes a free radical type photoinitiator and / or a cationic type photoinitiator.

4. The production method according to claim 3, wherein The photosensitive resin includes one or more of polyurethane acrylate, epoxy acrylate, polyester acrylate, epoxy resin, vinyl ether resin, monofunctional photosensitive resin monomer, difunctional photosensitive resin monomer and trifunctional photosensitive resin monomer.

5. The production method according to claim 1, wherein The mixing includes homogenization treatment and three-roll grinding treatment in sequence; The mixing includes mixing photosensitive resin, photoinitiator and defoaming agent to obtain 3D printing resin; The mesoporous silica microspheres and inorganic ceramic powder are divided into three parts, which are sequentially added to the 3D printing resin for homogenization treatment and then three-roll grinding treatment; The homogenization treatment has a rotation speed of 300-1000r / min, a time of 1-5min and a vacuum degree of 0-1.3kPa; The three-roll grinding treatment uses a three-roll mill with a roller rotation speed of 1-500r / min and a gap between adjacent rollers decreasing from 500μm to the larger value of the particle size of the mesoporous silica and inorganic ceramic powder.

6. The production method according to claim 1, wherein The printing layer thickness of the light-curing 3D printing process is 10-200 μm, the exposure time is 0.5-30 s, and the required energy density is 2-75 mW / cm 2 .

7. The production method according to claim 1, wherein The vacuum oil immersion treatment uses one or more of hydrocarbon lubricating oil, ester lubricating oil, mineral base oil and polyether.

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