Preparation Of High Performance Cordierite Photosensitive Resin Ceramic Slurries And Research On Its Photo Curing Characteristics

Cordierite ceramics have the advantages of low thermal expansion coefficient,good thermal shock resistance,stable chemical properties,small thermal conductivity,and low dielectric constant.They are widely used in the fields of automotive,electronics,metallurgy,chemical industry and environmental protection.However,the traditional ceramic modeling technology is difficult to manufacture complex ceramic structures which limits the application of cordierite ceramics.DLP 3D printing technology provides a new concept for the preparation of complex cordierite ceramic structures.The preparation of cordierite photosensitive resin ceramic slurry and the DLP printing and post-treatment process provide greater freedom for the design and application of cordierite ceramic materials and structures.The preparation of high solid loading and low viscosity cordierite photosensitive resin ceramic slurry was studied in this paper.The rheological properties and photo-curing properties of the slurry were studied.The relationships between the cordierite powder average particle size,solid loading and dispersant content and the viscosity and precipitation ratio of the slurry were established.The rule that the exposure time,solid loading and photoinitiator concentration affected the solidification thickness was investigated.In addition,the transmission depth DP and critical exposure intensity EC of the slurry were tested.The main conclusions are: the smaller the average particle diameter of the cordierite powder,the greater the viscosity of the slurry;as the solid loading increases,the viscosity of the slurry exhibits an exponential increase;the viscosity of the slurry decreases first and then increase with the increase of the dispersant content.The viscosity of the slurry is the smallest when the dispersant content is 5wt%;the biggest solid loading of the slurry can be prepared by cordierite powders with an average particle size of 7.41μm,3.00μm,0.35μm is about 65vol%,60vol%,and 50vol%,respectively.After optimization analysis,the powder particle size,solid loading,and dispersant content were 0.35μm,40vol%,and 5wt%,respectively.This slurry has the best performance.The slurry has a low viscosity and could be stored for a long time without sedimentation.The solidified thickness of the slurry increases first and then decreases with the increase of the photoinitiator concentration.A good effect can be obtained with a photoinitiator concentration of 2wt%;the transmission depth DP and the critical exposure intensity EC of the slurry as a whole decrease with increasing solid loading.This paper studies the DLP printing process and post-processing process,and optimizes printing parameters such as exposure time and optical power density.The effects of slurry solid loading,average particle size,and sintering temperature on the shrinkage rate of debinding and sintering were studied.The open porosity,relative theoretical density and bending strength of sintered samples of cordierite ceramics were measured.The surface and internal morphology of the sintered samples were observed using a scanning electron microscope.The main conclusions are: DLP printer have an optical power density of 12.74 m W/cm2 and an exposure time of 3s are the best printing parameters.Its cured thickness enables continuous bonding between layers,with high printing accuracy.The shrinkage rate in the Z-axis direction of the print slice layering direction is greater than the shrinkage rate in the X,Y direction on the print plane.The shrinkage of the sample is mainly concentrated in the sintering stage,and the shrinkage rate in the sintering stage is much larger than that in the debinding stage.When the sintering temperature is 1350 ℃,the relative theoretical density and bending strength of cordierite ceramics are the highest.With the increase of solid loading,the shrinkage rate in all directions and the open porosity of cordierite ceramics decreased,and the relative theoretical density and bending strength increased.As the particle size of the powder increases,the shrinkage rate of the sample gradually decreases in all directions.The sample with a particle size of 3.00μm has the smallest open porosity,has the highest relative density,and the larger bending strength,which is the optimal average particle size of the powder in this study.