Research On Mechanical Properties Of ZrO₂ Ceramics Based On 3D Printing

With the progress of science and technology and social development,people is showing more and more high requirement in dental restoration.Zirconia all-ceramic restorations are widely used in the field of dental restoration due to their natural color,good mechanical properties and so on.The application of ceramic materials in dental restorations is limited because of the traditional manufacturing process need long production cycle,complicated process and high cost.The microfluidic extrusion of 3D printing technology can custom miniature ceramic components with complex shapes in personally by a selective slurry extrusion system.In this paper,the zirconia ceramic slurry is the molding object,and through adding the tourmaline into zirconia ceramic slurry to improve the physical and chemical properties.The zirconia all-ceramic crown is quickly fabricated through the micro-extrusion extrusion 3D printing technology.The influence of this process on zirconia mechanical properties is tested and analysised.Firstly,the influence of pH value,amount of dispersant and tourmaline content on the stability of zirconia ceramic slurry was studied.When the pH is 9,the content of dispersant is 2%,tourmaline content of 1.5%,the stability of the slurry is best;the results show that the forming effect of the selective slurry extrusion system is better when the milling time is 20h and the solid content is in the range of 45%-48%.Secondly,through the mathematical description of the extrusion process and a large number of experiments to find out the best shape process parameters of zirconia ceramic slurry by the selective slurry extrusion system.When the extrusion head extrusion diameter is 0.44mm,cylinder diameter is 13mm,layer thickness is 0.35mm,extrusion speed is0.5mm/s,the molding is the best.Finally,the zirconia ceramics were sintered by pressureless sintering in different group.The effects of different solid contents,different tourmaline contents and different sintering temperatures on the mechanical properties of the specimens were studied and analyzed.When the solid content is 48%,the content of tourmaline is 1.5%and the sintering temperature is 1480℃,the flexural strength reaches 854 MPa and the fracture toughness reaches 9.62 MPa/m^1/2.