Research On Preparation Technology Of 3D Printing ZrO₂ Ceramic

Zirconia ceramic material are widely used in chemical and chemical industries,aerospace,energy and biomedical fields,owing to its good chemical stability,high strength,high hardness,and excellent biocompatibility,etc.However,due to its high strength and high brittleness,the traditional molding method has high cost and long cycle time for complex ceramic parts.As one of the 3D printing technologies,stereolithography technology is particularly good at high-precision molding of fine and complex ceramics,overcoming the difficulties in traditional ceramic molding processes.In this paper,three parts of work were carried out for the manufacturing of ZrO₂ ceramics based on the DLP technology:（1）Preparation of ZrO₂ ceramics suspension for stereolithography.Based on the dispersion of ZrO₂ particles in photocurable resin,the effects of powder properties,dispersant,and solid content of slurry on the rheological properties of photocurable suspension were studied.It was found that use the small specific surface area and high sphericity ZrO₂ powder is more conducive to the preparation of high solid content and low viscosity suspension.The optimal additional amount of dispersant X-100 was 4 wt.%,and the dispersion mechanism was analyzed.The solid content experiment of the slurry found that the relationship between the solid content of the suspension and the viscosity satisfies the Krieger–Dougherty model;（2）DLP molding of ceramic slurry.On the basis of analyzing and studying the curing performance of light-curing resin,then according to Beer-Lambert’s law,the curing kinetics of ZrO₂ photocurable slurry was studied.By controlling the exposure intensity to be constant,the change of the cured thickness of the slurry with different exposure time was studied.It was found that the critical energy dose in the depth direction was 131.02 m J/cm²,and the sensitivity in the depth direction was 97.60μm,which provides theoretical guidance for the subsequent printing parameter settings;（3）Research on debinding of ceramic green body.Overcame the problems of 3D printing ceramics that are difficult to debinding and easy to crack.According to the TG-DTG curve,the law of debinding in different stages is summarized,and the whole debinding process is divided into three parts:The initial,mid,and late stages of debinding correspond to the three temperature ranges of 80-200℃,200-400℃,and 400-600℃,respectively.Then debinding experiments were carried out in these three temperature ranges,the causes of defects in the debinding process were analyzed,and the debinding process in these three temperature ranges was optimized.Finally,a complete and defect-free ceramic body is obtained.Ceramic green body exhibits obvious shrinkage before and after sintering,after testing,the average shrinkage rate is 28.17%,and the density measured by the Archimedes method is 6.03 g/cm³,which corresponding relative density is 98.85%,and the average bending strength is 644 MPa,the Vickers hardness can reach 15.19 GPa,the fracture toughness is 9 MPa.m^1/2,and the performance is close to zirconia ceramics prepared by traditional methods.