As a reliable additive manufacturing technology,the stereolithography(SLA)ceramic core necessitates a tailored sintering process to achieve optimal performance.This study explored the effects of final sintering temper...As a reliable additive manufacturing technology,the stereolithography(SLA)ceramic core necessitates a tailored sintering process to achieve optimal performance.This study explored the effects of final sintering temperatures(specifically 1,150,1,250,and 1,300°C)on the properties of SLA-fabricated SiO_(2)-based ceramic cores reinforced with nano-ZrO_(2)(at concentrations of 1.0wt.%,1.5wt.%,and 2.0wt.%).The results demonstrate that increasing the final sintering temperature and the incorporation of nano-ZrO_(2)enhance the viscous fiow of quartz glass,resulting in a higher sintering degree.As the final sintering temperature rises,the ceramic samples exhibit increased shrinkage rate,decreased apparent porosity,and increased bulk density.Higher final sintering temperatures also promote greater cristobalite precipitation,promoting an increase in the amount and precipitation rate of quartz during investment casting.The formation of a cristobalite and ZrSiO_4 network at elevated temperatures effectively inhibits the viscous flow of quartz glass,thereby significantly improving high-temperature flexural strength and creep resistance of ceramic cores.When the content of nano-ZrO_(2)is between 1.5wt.%and 2.0wt.%,the final sintering temperature of 1,250°C is the best choice.Under these conditions,the shrinkage rate along the Z direction ranges from 3.35%to 3.68%,the porosity lies between 25.57%and 26.03%,the bulk density varies from 1.612 to 1.645 g·cm^(-3),the room temperature fiexural strength is between 26.79 and 27.85 MPa,and the fiexural strength at high temperatures is within the range of 30.77 to 33.02 MPa.The defiection at high-temperatures is 3.37-5.31 mm,while the surface roughness of the upper surface is 3.26-4.79μm,and the surface roughness of the side surface is 4.97-5.79μm.These findings provide valuable guidance for optimizing the sintering processes of SLA ceramic cores,offering potential for industrial applications.展开更多
In this work,aluminum oxide(Al2O3) ceramic samples were fabricated by 3D stereolithography printing.Printing process was followed by debinding and sintering.In addition,the effect of sintering temperature on micro str...In this work,aluminum oxide(Al2O3) ceramic samples were fabricated by 3D stereolithography printing.Printing process was followed by debinding and sintering.In addition,the effect of sintering temperature on micro structure and properties was investigated.Flexure strength was observed to increase with increasing sintering temperature due to fewer pores,fewer defects and stronger grain boundary bonding of samples at higher sintering temperatures.Maximum flexure strength of 138.5 MPa was obtained when sintering temperature was 150℃.Furthermore,the shrinkage along length direction decreased with the decreasing sintering temperature until reaching minimum value of 1.02% after sintering at 1200℃.After sintering at 1280℃,flexure strength was 24.0 MPa and the shrinkage along length direction was 2.1%,which meets demands of ceramic core.展开更多
Ceramic cores with complex structures and optimized properties are critical for hollow turbine blades applied in aeroengines.Compared to traditional methods,additive manufacturing(AM)presents great advantages in formi...Ceramic cores with complex structures and optimized properties are critical for hollow turbine blades applied in aeroengines.Compared to traditional methods,additive manufacturing(AM)presents great advantages in forming complex ceramic cores,but how to balance the porosity and strength is an enormous challenge.In this work,alumina ceramic cores with high porosity,moderate strength,and low high-temperature deflection were prepared using stereolithography(SLA)3D printing by a novel powder gradation design strategy.The contradiction between porosity and flexural strength is well adjusted when the mass ratio of the coarse,medium,and fine particles is 2:1:1 and the sintering temperature is 1600℃.The fracture mode of coarse particles in sintered SLA 3D printing ceramic transforms from intergranular fracture to transgranular fracture with the increase of sintering temperature and the proportion of fine powders in powder system.The sintered porosity has a greater influence on the high-temperature deflection of SLA 3D printed ceramic cores than grain size.On this basis,a"non-skeleton"microstructure model of SLA 3D printed alumina ceramic cores is created to explain the relationship between the sintering process and properties.As a result,high porosity(36.4%),appropriate strength(50.1 MPa),and low high-temperature deflection(2.27 mm)were achieved by optimizing particle size gradation and sintering process,which provides an insight into the important enhancement of the comprehensive properties of SLA 3D printed ceramic cores.展开更多
Silica-based ceramic cores have been widely used to fabricate aero-engine hollow blades due to their moderate high temperature mechanical properties and excellent leachability.In this study,silica-based ceramics with ...Silica-based ceramic cores have been widely used to fabricate aero-engine hollow blades due to their moderate high temperature mechanical properties and excellent leachability.In this study,silica-based ceramics with SiC fiber addition were prepared via stereolithography,and the influence of SiC fiber content on mechanical properties of the obtained silica-based ceramics was investigated.With the increase of SiC fiber content,linear shrinkage gradually decreased,while room temperature flexural strength and high temperature flexural strength first increased and then decreased.As SiC fiber content increased to 4.0 wt%,linear shrinkage was reduced to 0.62%resulting from the oxidation of SiC.Furthermore,room temperature flexural strength was improved from 11.79 MPa to 23.83 MPa and high temperature flexural strength was enhanced from 15.64 MPa to 34.62 MPa with 4.0 wt%SiC fiber addition due to the reinforcement of fibers and the enhancedβ-cristobalite content,which meets the need of ceramic cores.Therefore,it demonstrates the capability of fabricating high-performance and high-precision silica-based ceramic cores reinforced by SiC fibers via stereolithography for rapid manufacturing of hollow blades.展开更多
As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle siz...As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle size and distribution,particle morphology on the rheological behavior of zirconia resin-based suspensions were investigated intensively.Results show that the specific surface area of the powder is the most important factor affecting slurry viscosity.Choosing low specific surface area and quasi-spherical shaped powder is more likely to obtain low viscosity slurries.In addition,the influence of solid loading on the flow behavior were also studied using Krieger-Dougherty model.Zirconia samples with the relative density of(97.83±0.33)%were obtained after sintering at 1550℃.No obvious abnormal grain growth in the microstructure of the sintered body is observed.Results indicate that after the optimization of the processing parameters with the help of rheology characterization,complex-shaped high-quality zirconia parts can be obtained using the stereolithography technique.展开更多
A novel cationic photosensitive resin(3 DSLR-01) for stereolithography 3 D printing was prepared with 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexane carboxylate(2021 P),1,4-cyclohexanedimethanol glycidyl ether(JX-...A novel cationic photosensitive resin(3 DSLR-01) for stereolithography 3 D printing was prepared with 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexane carboxylate(2021 P),1,4-cyclohexanedimethanol glycidyl ether(JX-026), diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate(S-186), polycaprolactone polyol(Polyol-0305), novolac epoxy resin(F-51), bis(3-ethyl-3-oxetanylmethyl) ether(S-221) and a mixture of triarylsulfonium hexafluoroantimonate salts solution(UVI-6976). The properties of the photosensitive resin and its UV-cured films were investigated by some instruments and equipment.The experimental results show that the critical exposure(Ec) of the photosensitive resin is 16.3 mJ/cm^2, the penetration depth(Dp) is 0.14 mm, and the optical property of the photosensitive resin is excellent. Rectangle plates were printed by using a stereolithography apparatus(HRPL-150 A) with the photosensitive resin as the manufacturing material, and the shrinkage rates of the plates were less than 0.60%, which showed that the accuracy of the manufactured plates was very high.展开更多
Bis[2-(3,4-epoxycyclohexyl)ethyl]octamethyltetrasiloxane is also called diepoxycyclohexylethyl octamethyltetrasiloxane. In the present paper, diepoxycyclohexylethyl octamethyltetrasiloxane was synthesized, and the syn...Bis[2-(3,4-epoxycyclohexyl)ethyl]octamethyltetrasiloxane is also called diepoxycyclohexylethyl octamethyltetrasiloxane. In the present paper, diepoxycyclohexylethyl octamethyltetrasiloxane was synthesized, and the synthesized product was characterized by FTIR and 1 HMR. The synthesized product was compounded with some acrylates and an expoxide as well as photoinitiators to obtain a 3D printing stereolithography resin(3DSLR111). The properties of 3DSLR111 and its UV-cured samples were investigated by some instruments and equipments. The experimental results show that the critical exposure(Ec) of 3DSLR111 is 10.1 mJ/cm^2, its penetration depth(Dp) is 0.15 mm, and its viscosity at 30 ℃ is 319 mPa·s. Some samples were printed with 3DSLR111, and their linear shrinkage and warping factor were evaluated. The linear shrinkage and the curl distortion factor are less than 0.80% and 7.30%, respectively, which indicates that the sample printed with 3DSLR111 has high accuracy, and that the synthesized diepoxycyclohexylethyl octamethyltetrasiloxane can be well applied to the preparation of the photosensitive resin for stereolithography 3D printing.展开更多
Calcium phosphate(CaP)has been widely used for bone defect repair due to good biocompatibility and osteoconductivity.Additive manufacture of calcium phosphate bioceramics with tailored architectures and improved mecha...Calcium phosphate(CaP)has been widely used for bone defect repair due to good biocompatibility and osteoconductivity.Additive manufacture of calcium phosphate bioceramics with tailored architectures and improved mechanical properties has recently attracted great attention.Herein,calcium phosphate nanoparticles with the size of~89-164 nm were synthesized by the hydrothermal treatment of amorphous calcium phosphate(ACP)precursors at 180°C for 24 h.Biofunctional elements including Mg,Sr and Zn have been doped into these calcium phosphate nanoparticles.Our results revealed that Mg^(2+)ions played critical roles in formation of whitlockite-type calcium phosphate(not hydroxyapatite)from ACP precursors.Moreover,gyroid scaffolds with bionic triply periodic minimal surface structures were fabricated using stereolithography printing of these calcium phosphate nanoparticles,which are likely used as biofunctional scaffolds for bone repair.展开更多
Ceramic cores are widely used in investment casting,and ideal properties of cores are essential for high-quality castings.Under the circumstances requiring thick cores,solid cores are likely to encounter deformation a...Ceramic cores are widely used in investment casting,and ideal properties of cores are essential for high-quality castings.Under the circumstances requiring thick cores,solid cores are likely to encounter deformation and cracking defects due to the accumulation of shrinkage.Therefore,with the superiority of ceramic stereolithography in producing complex ceramic parts,hollow cores with lattice structures were designed and fabricated.The dimensional accuracy and properties of the green and sintered bodies were evaluated.Results show the dimensional accuracy of sintered cores is controlled within±0.25 mm benefited from the precise green bodies.The mechanical properties are not obviously deteriorated.The bending strength reaches 11.94 MPa at room temperature and 12.87 MPa at 1,500℃ with a creep deformation of 0.345 mm.Furthermore,casting verifications prove that the hollow cores meet the requirements of investment casting.Smooth casting surfaces are obtained,at the same time,the core-removal efficiency is improved by over 3 times.展开更多
The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show tha...The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show that the particle size of Si_(3)N_(4) powder has a signif icant influence on the rheological properties and stability of the slurry.When m_(D50=1.3μm):m_(D50=2.3μm)=3:7,the slurry viscosity is low and the sedimentation is slow.The most important thing is that with the increase of the solid loading of the slurry,the viscosity of the slurry increases,the stability becomes higher,and the curing thickness decreases.The curing thickness of Si_(3)N_(4) ceramic slurry with solid loading of 50 vol% can reach nearly 50μm.The above results finally show that the process optimizes the formulation of the slurry in rheological and curing properties.展开更多
A novel hybrid type photosensitive resin for stereolithography in 3D printing was prepared with bisphenol A type epoxy diacrylate （EA-612）, tripropylene glycol diacrylate （TPGDA）,ethoxylated trimethyolpropane tria...A novel hybrid type photosensitive resin for stereolithography in 3D printing was prepared with bisphenol A type epoxy diacrylate （EA-612）, tripropylene glycol diacrylate （TPGDA）,ethoxylated trimethyolpropane triacrylate（EO3TMPTA）, cycloaliphatic diepoxide（ERL-4221）,polycaprolactonepolyol（Polyol-0301）,1-hydroxy-cyclohphenyl ketone（Irgacure184）, and a mixture of triarylsulfonium hexafluoroantimonate salts （Ar3SSbF6）. The novel hybrid type photosensitive resin was the photosensitive resin of an epoxy-acrylate hybrid system, which proceeded free radical polymerization and cationic polymerization in ultraviolet （UV） laser. Cuboid parts and double-cantilever parts were fabricated by using a stereolithography apparatus with the novel hybrid type photosensitive resin as the processing material,and the dimension shrinkage factor and the curl factor were tested. The shrinkage factor was less than 2.00%,and the curl factor was less than 8.00%, which showed that the accuracy of the fabricated parts was high with the photosensitive resin for stereolithography in 3D printing.展开更多
Aiming at the part quality and building time problems in stereolithography （SL） caused by unreasonable building orientation, a part building orientation decision method in SL rapid prototyping （RP） is carried out....Aiming at the part quality and building time problems in stereolithography （SL） caused by unreasonable building orientation, a part building orientation decision method in SL rapid prototyping （RP） is carried out. Bringing into full consideration of the deformation, stair-stepping effect, overcure effect and building time related to the part fabrication orientation, and using evaluation function method, a multi-objective optimization model for the building orientation is defined. According to the difference in the angles between normal vectors of triangular facets in standard triangulation language （STL） model and z axis, the expressions of deformation area, stair-stepping area, overcure area are established. According to the characteristics in SL process, part building time is divided into four sections, that is, hatching scanning time, outline scanning time, support building time and layer waiting time. Expressions of each building time section are given. Considering the features of this optimization model, genetic algorithm （GA） is used to derive the optimization objective, related software is developed and optimization results are tested through experiments. Application shows that this method can effectively solve the quality and efficiency troubles caused by unreasonable part building orientation, an automatic orientation-determining program is developed and verified through test.展开更多
Bone defect repair remains a troubling problem in clinical orthopedics,which involves complex biological processes.Calcium phosphates(CaPs)have been widely used owing to their advantage of biocompatibility.However,sin...Bone defect repair remains a troubling problem in clinical orthopedics,which involves complex biological processes.Calcium phosphates(CaPs)have been widely used owing to their advantage of biocompatibility.However,single component and traditional fabrication methods cannot meet the requirements of bioadaptability during the tissue repair process.In this work,0%,5%,15%,25%wt%of BG-TCP(bioactive glass-β-tricalcium phosphate)bioresorbable scaffolds with triply-periodic minimal surfaces(TPMS)-gyroid structure were prepared by the stereolithography(SLA)technology.TPMS-gyroid structure provided an accurate mimicry of natural bone tissue,and the incorporation of BG improved the compressive strength ofβ-TCP matrix,matched with the defective bone(2–12 MPa).Rapid but tunable degradation kinetics(compared with pure TCP)of BG enabled the BG-TCP system to sh8ow adaptable biodegradability to new bone generation.In vitro studies have shown that composite scaffolds have better mechanical properties(7.82 MPa),and can released appropriate contents of calcium,phosphorous,and magnesium ions,which promoted the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)and angiogenic ability of endothelial progenitor cells(EPCs).Moreover,the in vivo assessment of rat femoral defect revealed that TPMS-structure-based TCP scaffolds accelerated bone ingrowth to the pores.Moreover,BG-TCP scaffolds,especially 15BG-TCP group,exhibited superior bone regeneration capacity at both 4 and 8 weeks,which achieved an optimal match between the rate of material degradation and tissue regeneration.In summary,this study provides insight into influences of bioactive components(BG)and bionic structures(TPMS)on the physical-chemical properties of materials,cell behavior and tissue regeneration,which offers a promising strategy to design bioadaptive ceramic scaffolds in the clinical treatment of bone defects.展开更多
New liquid free radical-cationic hybrid photopolymer, consisting of acrylate-based photocurable resin and epoxy-based photosensitive resin for stereolithography by UV laser was developed. The experiment results indica...New liquid free radical-cationic hybrid photopolymer, consisting of acrylate-based photocurable resin and epoxy-based photosensitive resin for stereolithography by UV laser was developed. The experiment results indicated that the hybrid photopolymer exhibits advantages of both the acrylate-based photosensitive resin and the epoxy-based photosensitive polymer contained in the hybrid system with relatively high photospeed and low linear shrinkage. Stereolithography parts without obvious distortion were built on the stereolithography apparatus HRPLA- I from this hybrid resin successfully and efficiently.展开更多
Surface hardness value is a commonly used indicator for describing the mechanical property of stere- olithography parts. In order to investigate colorants how to influence the surface hardness of colorful resin compon...Surface hardness value is a commonly used indicator for describing the mechanical property of stere- olithography parts. In order to investigate colorants how to influence the surface hardness of colorful resin component, a procedure is proposed to fabricate testing specimens based on color stereolithography technology in this study. Liquid photosensitive resin LPR2001 is mixed with two colorants(phthalocyanine blue and eosin powder) respectively before curing. The phthalocyanine blue powder is insoluble and only dispersive in the solid- liquid mixture which results in deposits. Therefore, surface modification is conducted to the phthalocyanine blue powder for improving wettability. By contrast, the eosin powder is dissoluble and does not cause any deposits in the liquid resin. Specimens are produced by laser curing colored resin and tested by MTSRNano Indenter XP system. The change of hardness values is illustrated at certain mass percentages of colorant. Comparisons and discussions are carried out to explain the colorants' efect. It is concluded that incorporating colorant to liquid resin results in decreasing the surface hardness of components. But sensibilization efect of the colorants also influences the curing process. Surface modification to the phthalocyanine blue powder is a feasible method to increase the hardness value of color stereolithography components. Dissolvable eosin has an approximate linear efect on surface hardness.展开更多
In recent years, Vantico A &T US Incorporation has developed a type of the hightest accuracy photosensitive resin: SL5510 stereolithography material(briefly named SL5510) to use in the stereolithography apparatus(...In recent years, Vantico A &T US Incorporation has developed a type of the hightest accuracy photosensitive resin: SL5510 stereolithography material(briefly named SL5510) to use in the stereolithography apparatus(SLA). In this paper, the thermal and mechanical properties were investigated for the fabricated specimens of SL5510 in the different UV post-cure time. This may instruct us to employ better the fabricated parts of SL5510.展开更多
Multi-material additive manufacturing(MMAM)takes full advantage of the ability to arbitrarily place materials of addi-tive manufacturing technology,enabling immense design free-dom and functional print capabilities.Am...Multi-material additive manufacturing(MMAM)takes full advantage of the ability to arbitrarily place materials of addi-tive manufacturing technology,enabling immense design free-dom and functional print capabilities.Among MMAM technologies,projection stereolithography(PSL)exhibits a great balance of high resolution and fast printing speed.However,fabrication accuracy of multi-material PSL is hin-dered by large overcure used to strengthen interfacial bond-ing weakened by chemical affinity and material-exchange process.We present a novel multi-step exposure method for multi-material PSL process to overcome this shortcoming.Firstly,the whole layer is moderately exposed producing over-cure of single-material PSL level to generate geometries.Then weakened interfaces are strengthened individually with addi-tional steps of exposure.The multi-step exposure is integrated into the already efficient materials printing order of multi-material PSL process.Curing depth and overcure of photocur-able resins are modeled and characterized.Exposure required to achieve sufficient interfacial bonding of single-material interfaces built through material-exchange process and multi-material interfaces with altering materials printing order is determined with tensile tests.Microfluidic channels are used to compare fabrication accuracy of traditional single-step exposure and our multi-step exposure method.This method can be widely applied in multi-material PSL to improve fabri-cation accuracy in a variety of applications including micro-fluidic devices.展开更多
Ceramic materials with intricate structures can be efficiently fabricated using stereolithography(SLA)based 3D printing technology,offering advantages over traditional methods.Sintering temperature has primary effect ...Ceramic materials with intricate structures can be efficiently fabricated using stereolithography(SLA)based 3D printing technology,offering advantages over traditional methods.Sintering temperature has primary effect on properties of ceramics.This study investigated the crucial sintering temperature for 3D printed ceramics to ensure the desired properties.The results indicate that all samples exhibit a consistent layered structure across the experimental sintering temperatures.When the sintering temperature is increased from 1,250℃ to 1,350℃,the grain's morphology changes from spherical to plate-like.Surface morphology analysis reveals a decrease in surface roughness at sintering temperatures above 1,350℃.Mechanical tests show improved flexural strength and stiffness as the sintering temperature rises.Friction and wear experiments demonstrate that as the sintering temperature increases from 1,450℃ to 1,550℃,the wear pattern on ceramic surfaces transitions from deep pits to shallow grooves.The increase in sintering temperature effectively enhances the wear resistance of 3D printed alumina ceramics.This improvement plays a significant role in expanding the application field of these ceramics,prolonging the lifespan of parts,reducing production costs,enhancing performance,and promoting environmental protection.In this study,ceramics achieve the highest strength and best wear resistance when sintered at 1,600℃,resulting in the best overall performance.展开更多
Silica ceramic cores have played an important part in the manufacture of hollow blades due to their excellent chemical stability and moderate high-temperature mechanical properties.In this study,silica-based ceramics ...Silica ceramic cores have played an important part in the manufacture of hollow blades due to their excellent chemical stability and moderate high-temperature mechanical properties.In this study,silica-based ceramics were prepared with Al_(2)0_(3) addition by stereolithography,and the influence of Al_(2)0_(3) content on mechanical properties of the silica-based ceramics was investigated.The Al_(2)0_(3) in silica-based ceramics can improve the mechanical properties by playing a role as a seed for the crystallization of fused silica into cristobalite.As a result,with the increase of Al_(2)0_(3) content,the linear shrinkage of the silica-based ceramics first decreased and then increased,while the room-temperature flexural strength and the high-temperature flexural strength first increased and then decreased.As the Al_(2)0_(3) content increased to 1.0 vol%,the linear shrinkage was reduced to 1.64%because of the blocked viscous flow caused by Al_(2)0_(3).Meanwhile,the room-temperature flexural strength and the high-temperature flexural strength were improved to 20.38 and 21.43 MPa with 1.0 vol%Al_(2)0_(3),respectively,due to the increased a-cristobalite and P-cristobalite content.Therefore,using the optimal content of Al_(2)0_(3) in silica-based ceramics can provide excellent mechanical properties,which are suitable for the application of ceramic cores in the manufacturing of hollow blades.展开更多
In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Bas...In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Based on this novel approach,Al_(2)O_(3)powder was coated with a homogeneous layer of amorphous Y2O3,with the coated AI2O3 powder found to make the microstructure of 3D printed Al_(2)O_(3) ceramic more uniform and refined,as compared with the conventional mechanical mixing(MM)of Al_(2)O_(3) and Y_(2)O_(3) powders.The grain size of Al_(2)O_(3) in Sample CP is 64.44%and 51.43%lower than those in the monolithic Al_(2)O_(3) ceramic and Sample MM,respectively.Sample CP has the highest flexural strength of 455.37±32.17 MPa,which is 14.85%and 25.45%higher than those of Samples MM and AL,respectively;also Sample CP has the highest Weibull modulus of 16.88 among the three kinds of samples.Moreover,the fine grained Sample CP has a close thermal conductivity to the coarse grained Sample MM because of the changes in morphology of Y_(3)Al_(5)O_(12) phase from semi-connected(Sample MM)to isolated(Sample CP).Finally,specially designed fin-type Al_(2)O_(3) ceramic heat sinks were successfully fabricated via the novel integrated process,which has been proven to be an effective method for fabricating complex-shaped Al_(2)O_(3) ceramic components with enhanced flexural strength and reliability.展开更多
基金supported by the Natural Science Foundation of Shanghai(No.23ZR1421500)the National Natural Science Foundation of China(Nos.52474412,52127807,52271035)+3 种基金the Shanghai Municipal Commission of Economy and Informatization(No.GYOJ2022-2-02)the United Innovation Program of Shanghai Commercial Aircraft Engine(No.AR966)the SPMI Project from Shanghai Academy of Spaceflight Technology(No.SPMI2022-06)the Ningbo International Science and Technology Cooperation Program(No.2023H004)。
文摘As a reliable additive manufacturing technology,the stereolithography(SLA)ceramic core necessitates a tailored sintering process to achieve optimal performance.This study explored the effects of final sintering temperatures(specifically 1,150,1,250,and 1,300°C)on the properties of SLA-fabricated SiO_(2)-based ceramic cores reinforced with nano-ZrO_(2)(at concentrations of 1.0wt.%,1.5wt.%,and 2.0wt.%).The results demonstrate that increasing the final sintering temperature and the incorporation of nano-ZrO_(2)enhance the viscous fiow of quartz glass,resulting in a higher sintering degree.As the final sintering temperature rises,the ceramic samples exhibit increased shrinkage rate,decreased apparent porosity,and increased bulk density.Higher final sintering temperatures also promote greater cristobalite precipitation,promoting an increase in the amount and precipitation rate of quartz during investment casting.The formation of a cristobalite and ZrSiO_4 network at elevated temperatures effectively inhibits the viscous flow of quartz glass,thereby significantly improving high-temperature flexural strength and creep resistance of ceramic cores.When the content of nano-ZrO_(2)is between 1.5wt.%and 2.0wt.%,the final sintering temperature of 1,250°C is the best choice.Under these conditions,the shrinkage rate along the Z direction ranges from 3.35%to 3.68%,the porosity lies between 25.57%and 26.03%,the bulk density varies from 1.612 to 1.645 g·cm^(-3),the room temperature fiexural strength is between 26.79 and 27.85 MPa,and the fiexural strength at high temperatures is within the range of 30.77 to 33.02 MPa.The defiection at high-temperatures is 3.37-5.31 mm,while the surface roughness of the upper surface is 3.26-4.79μm,and the surface roughness of the side surface is 4.97-5.79μm.These findings provide valuable guidance for optimizing the sintering processes of SLA ceramic cores,offering potential for industrial applications.
基金financially supported by the National Key Research and Development Program of China (No. 2018YFB1106600)the Chinese National Foundation for Natural Sciences under Contracts (No. 51672217)the Research Fund of the State Key Laboratory of Solidifi cation Processing (Grant No. 120-TZ-2015).
文摘In this work,aluminum oxide(Al2O3) ceramic samples were fabricated by 3D stereolithography printing.Printing process was followed by debinding and sintering.In addition,the effect of sintering temperature on micro structure and properties was investigated.Flexure strength was observed to increase with increasing sintering temperature due to fewer pores,fewer defects and stronger grain boundary bonding of samples at higher sintering temperatures.Maximum flexure strength of 138.5 MPa was obtained when sintering temperature was 150℃.Furthermore,the shrinkage along length direction decreased with the decreasing sintering temperature until reaching minimum value of 1.02% after sintering at 1200℃.After sintering at 1280℃,flexure strength was 24.0 MPa and the shrinkage along length direction was 2.1%,which meets demands of ceramic core.
基金financially supported by the National Natural Science Foundation of China(Nos.52130204,52174376,51822405)Guangdong Basic and Applied Basic Research Foundation(No.21201910250000848)+5 种基金Science and Technology Innovation Team Plan of Shaan Xi Province(No.2021TD-17)The Youth Innovation Team of Shaanxi UniversitiesJoint Research Funds of the Department of Science&Technology of Shaanxi Province and NPU(2020GXLH-Z-024)Key R&D Program of Shaan Xi Province(No.2019ZDLGY 04-04)Fundamental Research Funds for the Central Universities(No.D5000210902)Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(Nos.CX2021056 and CX2021066),China。
文摘Ceramic cores with complex structures and optimized properties are critical for hollow turbine blades applied in aeroengines.Compared to traditional methods,additive manufacturing(AM)presents great advantages in forming complex ceramic cores,but how to balance the porosity and strength is an enormous challenge.In this work,alumina ceramic cores with high porosity,moderate strength,and low high-temperature deflection were prepared using stereolithography(SLA)3D printing by a novel powder gradation design strategy.The contradiction between porosity and flexural strength is well adjusted when the mass ratio of the coarse,medium,and fine particles is 2:1:1 and the sintering temperature is 1600℃.The fracture mode of coarse particles in sintered SLA 3D printing ceramic transforms from intergranular fracture to transgranular fracture with the increase of sintering temperature and the proportion of fine powders in powder system.The sintered porosity has a greater influence on the high-temperature deflection of SLA 3D printed ceramic cores than grain size.On this basis,a"non-skeleton"microstructure model of SLA 3D printed alumina ceramic cores is created to explain the relationship between the sintering process and properties.As a result,high porosity(36.4%),appropriate strength(50.1 MPa),and low high-temperature deflection(2.27 mm)were achieved by optimizing particle size gradation and sintering process,which provides an insight into the important enhancement of the comprehensive properties of SLA 3D printed ceramic cores.
基金supported by National Science and Technology Major Project(no.2017-Ⅶ-0008-0102)National Natural Science Foundation of China(no.51975230)Fundamental Research Funds for the Central Universities(nos.2019kfy XMPY020,2020kfy FPZX003,2018KFYYXJJ030,2019kfy XKJC011)。
文摘Silica-based ceramic cores have been widely used to fabricate aero-engine hollow blades due to their moderate high temperature mechanical properties and excellent leachability.In this study,silica-based ceramics with SiC fiber addition were prepared via stereolithography,and the influence of SiC fiber content on mechanical properties of the obtained silica-based ceramics was investigated.With the increase of SiC fiber content,linear shrinkage gradually decreased,while room temperature flexural strength and high temperature flexural strength first increased and then decreased.As SiC fiber content increased to 4.0 wt%,linear shrinkage was reduced to 0.62%resulting from the oxidation of SiC.Furthermore,room temperature flexural strength was improved from 11.79 MPa to 23.83 MPa and high temperature flexural strength was enhanced from 15.64 MPa to 34.62 MPa with 4.0 wt%SiC fiber addition due to the reinforcement of fibers and the enhancedβ-cristobalite content,which meets the need of ceramic cores.Therefore,it demonstrates the capability of fabricating high-performance and high-precision silica-based ceramic cores reinforced by SiC fibers via stereolithography for rapid manufacturing of hollow blades.
基金National Key Research and Development Program of China(2017YFB0310400)National Natural Science Foundation of China(51572277,51702340)+1 种基金Shanghai Sailing Program(17YF1428800)Natural Science Foundation of Shanghai(17ZR1434800)。
文摘As for ceramic stereolithography technique,the preparation of suitable resin-based ceramic slurry is of primary importance.In this study,the effects of powder characteristics such as specific surface area,particle size and distribution,particle morphology on the rheological behavior of zirconia resin-based suspensions were investigated intensively.Results show that the specific surface area of the powder is the most important factor affecting slurry viscosity.Choosing low specific surface area and quasi-spherical shaped powder is more likely to obtain low viscosity slurries.In addition,the influence of solid loading on the flow behavior were also studied using Krieger-Dougherty model.Zirconia samples with the relative density of(97.83±0.33)%were obtained after sintering at 1550℃.No obvious abnormal grain growth in the microstructure of the sintered body is observed.Results indicate that after the optimization of the processing parameters with the help of rheology characterization,complex-shaped high-quality zirconia parts can be obtained using the stereolithography technique.
基金Funded by the National Natural Science Foundation of China(No.51563017)
文摘A novel cationic photosensitive resin(3 DSLR-01) for stereolithography 3 D printing was prepared with 3,4-epoxycyclohexylmethyl-3’,4’-epoxycyclohexane carboxylate(2021 P),1,4-cyclohexanedimethanol glycidyl ether(JX-026), diglycidyl 4,5-epoxycyclohexane-1,2-dicarboxylate(S-186), polycaprolactone polyol(Polyol-0305), novolac epoxy resin(F-51), bis(3-ethyl-3-oxetanylmethyl) ether(S-221) and a mixture of triarylsulfonium hexafluoroantimonate salts solution(UVI-6976). The properties of the photosensitive resin and its UV-cured films were investigated by some instruments and equipment.The experimental results show that the critical exposure(Ec) of the photosensitive resin is 16.3 mJ/cm^2, the penetration depth(Dp) is 0.14 mm, and the optical property of the photosensitive resin is excellent. Rectangle plates were printed by using a stereolithography apparatus(HRPL-150 A) with the photosensitive resin as the manufacturing material, and the shrinkage rates of the plates were less than 0.60%, which showed that the accuracy of the manufactured plates was very high.
基金Funded by the National Natural Science Foundation of China(No.51563017)
文摘Bis[2-(3,4-epoxycyclohexyl)ethyl]octamethyltetrasiloxane is also called diepoxycyclohexylethyl octamethyltetrasiloxane. In the present paper, diepoxycyclohexylethyl octamethyltetrasiloxane was synthesized, and the synthesized product was characterized by FTIR and 1 HMR. The synthesized product was compounded with some acrylates and an expoxide as well as photoinitiators to obtain a 3D printing stereolithography resin(3DSLR111). The properties of 3DSLR111 and its UV-cured samples were investigated by some instruments and equipments. The experimental results show that the critical exposure(Ec) of 3DSLR111 is 10.1 mJ/cm^2, its penetration depth(Dp) is 0.15 mm, and its viscosity at 30 ℃ is 319 mPa·s. Some samples were printed with 3DSLR111, and their linear shrinkage and warping factor were evaluated. The linear shrinkage and the curl distortion factor are less than 0.80% and 7.30%, respectively, which indicates that the sample printed with 3DSLR111 has high accuracy, and that the synthesized diepoxycyclohexylethyl octamethyltetrasiloxane can be well applied to the preparation of the photosensitive resin for stereolithography 3D printing.
基金financially supported by the National Key Research and Development Program of China from Ministry of Science and Technology(No.2016YFC1100502)the Doctoral Research Foundation Program of Liaoning Province(No.2019-BS-256)+2 种基金the Key Research Program of Frontier Sciences(No.QYZDY-SSWJSC031)from Chinese Academy of Sciences(CAS)Key Research and Development Program of Liaoning Province(No.201703031)Shenyang Key R&D and Technology Transfer Program(No.Z17-7023)。
文摘Calcium phosphate(CaP)has been widely used for bone defect repair due to good biocompatibility and osteoconductivity.Additive manufacture of calcium phosphate bioceramics with tailored architectures and improved mechanical properties has recently attracted great attention.Herein,calcium phosphate nanoparticles with the size of~89-164 nm were synthesized by the hydrothermal treatment of amorphous calcium phosphate(ACP)precursors at 180°C for 24 h.Biofunctional elements including Mg,Sr and Zn have been doped into these calcium phosphate nanoparticles.Our results revealed that Mg^(2+)ions played critical roles in formation of whitlockite-type calcium phosphate(not hydroxyapatite)from ACP precursors.Moreover,gyroid scaffolds with bionic triply periodic minimal surface structures were fabricated using stereolithography printing of these calcium phosphate nanoparticles,which are likely used as biofunctional scaffolds for bone repair.
基金supported by the National Natural Science Foundation of China (Grant No. 52175333)Tribology Science Fund of the State Key Laboratory of Tribology,Tsinghua University (Grant No. SKLT2021B05)+1 种基金Foshan Science and Technology Innovation Team Project (Grant No. 2018IT100142)National Science and Technology Major Project of China (Grant No. J2019-VII-0002-0142)
文摘Ceramic cores are widely used in investment casting,and ideal properties of cores are essential for high-quality castings.Under the circumstances requiring thick cores,solid cores are likely to encounter deformation and cracking defects due to the accumulation of shrinkage.Therefore,with the superiority of ceramic stereolithography in producing complex ceramic parts,hollow cores with lattice structures were designed and fabricated.The dimensional accuracy and properties of the green and sintered bodies were evaluated.Results show the dimensional accuracy of sintered cores is controlled within±0.25 mm benefited from the precise green bodies.The mechanical properties are not obviously deteriorated.The bending strength reaches 11.94 MPa at room temperature and 12.87 MPa at 1,500℃ with a creep deformation of 0.345 mm.Furthermore,casting verifications prove that the hollow cores meet the requirements of investment casting.Smooth casting surfaces are obtained,at the same time,the core-removal efficiency is improved by over 3 times.
基金Funded by National Natural Science Foundation of China (No.43200021)。
文摘The effects of particle size,gradation and solid loading of silicon nitride (Si_(3)N_(4)) on the rheological behavior and curing properties of ceramic slurry are studied by stereolithography (SLA).The results show that the particle size of Si_(3)N_(4) powder has a signif icant influence on the rheological properties and stability of the slurry.When m_(D50=1.3μm):m_(D50=2.3μm)=3:7,the slurry viscosity is low and the sedimentation is slow.The most important thing is that with the increase of the solid loading of the slurry,the viscosity of the slurry increases,the stability becomes higher,and the curing thickness decreases.The curing thickness of Si_(3)N_(4) ceramic slurry with solid loading of 50 vol% can reach nearly 50μm.The above results finally show that the process optimizes the formulation of the slurry in rheological and curing properties.
基金Funded by the National Natural Science Foundation of China(No.51563017)the Natural Science Foundation of Jiangxi Province(No.20142BAB206029)
文摘A novel hybrid type photosensitive resin for stereolithography in 3D printing was prepared with bisphenol A type epoxy diacrylate （EA-612）, tripropylene glycol diacrylate （TPGDA）,ethoxylated trimethyolpropane triacrylate（EO3TMPTA）, cycloaliphatic diepoxide（ERL-4221）,polycaprolactonepolyol（Polyol-0301）,1-hydroxy-cyclohphenyl ketone（Irgacure184）, and a mixture of triarylsulfonium hexafluoroantimonate salts （Ar3SSbF6）. The novel hybrid type photosensitive resin was the photosensitive resin of an epoxy-acrylate hybrid system, which proceeded free radical polymerization and cationic polymerization in ultraviolet （UV） laser. Cuboid parts and double-cantilever parts were fabricated by using a stereolithography apparatus with the novel hybrid type photosensitive resin as the processing material,and the dimension shrinkage factor and the curl factor were tested. The shrinkage factor was less than 2.00%,and the curl factor was less than 8.00%, which showed that the accuracy of the fabricated parts was high with the photosensitive resin for stereolithography in 3D printing.
基金This project is supported by National Hi-tech Research and Development Program of China(863 Program, No.2005AA414020).
文摘Aiming at the part quality and building time problems in stereolithography （SL） caused by unreasonable building orientation, a part building orientation decision method in SL rapid prototyping （RP） is carried out. Bringing into full consideration of the deformation, stair-stepping effect, overcure effect and building time related to the part fabrication orientation, and using evaluation function method, a multi-objective optimization model for the building orientation is defined. According to the difference in the angles between normal vectors of triangular facets in standard triangulation language （STL） model and z axis, the expressions of deformation area, stair-stepping area, overcure area are established. According to the characteristics in SL process, part building time is divided into four sections, that is, hatching scanning time, outline scanning time, support building time and layer waiting time. Expressions of each building time section are given. Considering the features of this optimization model, genetic algorithm （GA） is used to derive the optimization objective, related software is developed and optimization results are tested through experiments. Application shows that this method can effectively solve the quality and efficiency troubles caused by unreasonable part building orientation, an automatic orientation-determining program is developed and verified through test.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFB4601402)the National Natural Science Foundation of China(Nos.32201109,51772233)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Nos.2022B1515120052,2021A1515110557)the Key Basic Research Program of Shenzhen(No.JCYJ20200109150218836)the Chaozhou Branch of Chemistry and Chemical Engineering Guangdong Laboratory(No.HJL202202A002)。
文摘Bone defect repair remains a troubling problem in clinical orthopedics,which involves complex biological processes.Calcium phosphates(CaPs)have been widely used owing to their advantage of biocompatibility.However,single component and traditional fabrication methods cannot meet the requirements of bioadaptability during the tissue repair process.In this work,0%,5%,15%,25%wt%of BG-TCP(bioactive glass-β-tricalcium phosphate)bioresorbable scaffolds with triply-periodic minimal surfaces(TPMS)-gyroid structure were prepared by the stereolithography(SLA)technology.TPMS-gyroid structure provided an accurate mimicry of natural bone tissue,and the incorporation of BG improved the compressive strength ofβ-TCP matrix,matched with the defective bone(2–12 MPa).Rapid but tunable degradation kinetics(compared with pure TCP)of BG enabled the BG-TCP system to sh8ow adaptable biodegradability to new bone generation.In vitro studies have shown that composite scaffolds have better mechanical properties(7.82 MPa),and can released appropriate contents of calcium,phosphorous,and magnesium ions,which promoted the osteogenic differentiation of bone marrow mesenchymal stem cells(BMSCs)and angiogenic ability of endothelial progenitor cells(EPCs).Moreover,the in vivo assessment of rat femoral defect revealed that TPMS-structure-based TCP scaffolds accelerated bone ingrowth to the pores.Moreover,BG-TCP scaffolds,especially 15BG-TCP group,exhibited superior bone regeneration capacity at both 4 and 8 weeks,which achieved an optimal match between the rate of material degradation and tissue regeneration.In summary,this study provides insight into influences of bioactive components(BG)and bionic structures(TPMS)on the physical-chemical properties of materials,cell behavior and tissue regeneration,which offers a promising strategy to design bioadaptive ceramic scaffolds in the clinical treatment of bone defects.
文摘New liquid free radical-cationic hybrid photopolymer, consisting of acrylate-based photocurable resin and epoxy-based photosensitive resin for stereolithography by UV laser was developed. The experiment results indicated that the hybrid photopolymer exhibits advantages of both the acrylate-based photosensitive resin and the epoxy-based photosensitive polymer contained in the hybrid system with relatively high photospeed and low linear shrinkage. Stereolithography parts without obvious distortion were built on the stereolithography apparatus HRPLA- I from this hybrid resin successfully and efficiently.
基金the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20112302120054)the Fundamental Research Funds for Central Universities(No.HIT.NSRIF.201169)
文摘Surface hardness value is a commonly used indicator for describing the mechanical property of stere- olithography parts. In order to investigate colorants how to influence the surface hardness of colorful resin component, a procedure is proposed to fabricate testing specimens based on color stereolithography technology in this study. Liquid photosensitive resin LPR2001 is mixed with two colorants(phthalocyanine blue and eosin powder) respectively before curing. The phthalocyanine blue powder is insoluble and only dispersive in the solid- liquid mixture which results in deposits. Therefore, surface modification is conducted to the phthalocyanine blue powder for improving wettability. By contrast, the eosin powder is dissoluble and does not cause any deposits in the liquid resin. Specimens are produced by laser curing colored resin and tested by MTSRNano Indenter XP system. The change of hardness values is illustrated at certain mass percentages of colorant. Comparisons and discussions are carried out to explain the colorants' efect. It is concluded that incorporating colorant to liquid resin results in decreasing the surface hardness of components. But sensibilization efect of the colorants also influences the curing process. Surface modification to the phthalocyanine blue powder is a feasible method to increase the hardness value of color stereolithography components. Dissolvable eosin has an approximate linear efect on surface hardness.
基金This research was supported by the Key Science and Technology Foundation of Hubei Province Scientific Committee (2001P0205) and theNational"863"H-Tech Foundation (2002AA6Z3083)
文摘In recent years, Vantico A &T US Incorporation has developed a type of the hightest accuracy photosensitive resin: SL5510 stereolithography material(briefly named SL5510) to use in the stereolithography apparatus(SLA). In this paper, the thermal and mechanical properties were investigated for the fabricated specimens of SL5510 in the different UV post-cure time. This may instruct us to employ better the fabricated parts of SL5510.
基金supported by the National Key Research and Development Program of China [2022YFB4600102]National Natural Science Foundation of China [52125505,U20A20297,52275561,U23A20637].
文摘Multi-material additive manufacturing(MMAM)takes full advantage of the ability to arbitrarily place materials of addi-tive manufacturing technology,enabling immense design free-dom and functional print capabilities.Among MMAM technologies,projection stereolithography(PSL)exhibits a great balance of high resolution and fast printing speed.However,fabrication accuracy of multi-material PSL is hin-dered by large overcure used to strengthen interfacial bond-ing weakened by chemical affinity and material-exchange process.We present a novel multi-step exposure method for multi-material PSL process to overcome this shortcoming.Firstly,the whole layer is moderately exposed producing over-cure of single-material PSL level to generate geometries.Then weakened interfaces are strengthened individually with addi-tional steps of exposure.The multi-step exposure is integrated into the already efficient materials printing order of multi-material PSL process.Curing depth and overcure of photocur-able resins are modeled and characterized.Exposure required to achieve sufficient interfacial bonding of single-material interfaces built through material-exchange process and multi-material interfaces with altering materials printing order is determined with tensile tests.Microfluidic channels are used to compare fabrication accuracy of traditional single-step exposure and our multi-step exposure method.This method can be widely applied in multi-material PSL to improve fabri-cation accuracy in a variety of applications including micro-fluidic devices.
基金supported by the Xinjiang Tianchi Talent Introduction Plan (51052300585)the Fundamental Research Funds for Autonomous Region Universities (XJEDU2022P002)+1 种基金the Natural science foundation project of Xinjiang Uygur Autonomous Region (2023D01C192,2023D01C33)the Tianshan Innovation Team Program of Xinjiang Uygur Autonomous Region (2023D14001)。
文摘Ceramic materials with intricate structures can be efficiently fabricated using stereolithography(SLA)based 3D printing technology,offering advantages over traditional methods.Sintering temperature has primary effect on properties of ceramics.This study investigated the crucial sintering temperature for 3D printed ceramics to ensure the desired properties.The results indicate that all samples exhibit a consistent layered structure across the experimental sintering temperatures.When the sintering temperature is increased from 1,250℃ to 1,350℃,the grain's morphology changes from spherical to plate-like.Surface morphology analysis reveals a decrease in surface roughness at sintering temperatures above 1,350℃.Mechanical tests show improved flexural strength and stiffness as the sintering temperature rises.Friction and wear experiments demonstrate that as the sintering temperature increases from 1,450℃ to 1,550℃,the wear pattern on ceramic surfaces transitions from deep pits to shallow grooves.The increase in sintering temperature effectively enhances the wear resistance of 3D printed alumina ceramics.This improvement plays a significant role in expanding the application field of these ceramics,prolonging the lifespan of parts,reducing production costs,enhancing performance,and promoting environmental protection.In this study,ceramics achieve the highest strength and best wear resistance when sintered at 1,600℃,resulting in the best overall performance.
基金supported by the National Science and Technology Major Project(2017-VII-0008-0102)the National Natural Science Foundation of China(51975230)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure(SKL201903SIC).
文摘Silica ceramic cores have played an important part in the manufacture of hollow blades due to their excellent chemical stability and moderate high-temperature mechanical properties.In this study,silica-based ceramics were prepared with Al_(2)0_(3) addition by stereolithography,and the influence of Al_(2)0_(3) content on mechanical properties of the silica-based ceramics was investigated.The Al_(2)0_(3) in silica-based ceramics can improve the mechanical properties by playing a role as a seed for the crystallization of fused silica into cristobalite.As a result,with the increase of Al_(2)0_(3) content,the linear shrinkage of the silica-based ceramics first decreased and then increased,while the room-temperature flexural strength and the high-temperature flexural strength first increased and then decreased.As the Al_(2)0_(3) content increased to 1.0 vol%,the linear shrinkage was reduced to 1.64%because of the blocked viscous flow caused by Al_(2)0_(3).Meanwhile,the room-temperature flexural strength and the high-temperature flexural strength were improved to 20.38 and 21.43 MPa with 1.0 vol%Al_(2)0_(3),respectively,due to the increased a-cristobalite and P-cristobalite content.Therefore,using the optimal content of Al_(2)0_(3) in silica-based ceramics can provide excellent mechanical properties,which are suitable for the application of ceramic cores in the manufacturing of hollow blades.
基金supported by the Local Innovative and Research Team Project of Guangdong Province(Grant No.2017BT01C169)the Opening Project of State Key Laboratory of Green Building Materials(Grant No.2019GBM03)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2020A1515010004)the Natural Science Foundation of Guangdong Province(Grant No.2018A030313353)the Science and Technology Program of Guangzhou(Grant No.201904010357).
文摘In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Based on this novel approach,Al_(2)O_(3)powder was coated with a homogeneous layer of amorphous Y2O3,with the coated AI2O3 powder found to make the microstructure of 3D printed Al_(2)O_(3) ceramic more uniform and refined,as compared with the conventional mechanical mixing(MM)of Al_(2)O_(3) and Y_(2)O_(3) powders.The grain size of Al_(2)O_(3) in Sample CP is 64.44%and 51.43%lower than those in the monolithic Al_(2)O_(3) ceramic and Sample MM,respectively.Sample CP has the highest flexural strength of 455.37±32.17 MPa,which is 14.85%and 25.45%higher than those of Samples MM and AL,respectively;also Sample CP has the highest Weibull modulus of 16.88 among the three kinds of samples.Moreover,the fine grained Sample CP has a close thermal conductivity to the coarse grained Sample MM because of the changes in morphology of Y_(3)Al_(5)O_(12) phase from semi-connected(Sample MM)to isolated(Sample CP).Finally,specially designed fin-type Al_(2)O_(3) ceramic heat sinks were successfully fabricated via the novel integrated process,which has been proven to be an effective method for fabricating complex-shaped Al_(2)O_(3) ceramic components with enhanced flexural strength and reliability.
