Study On Properties And Preparation Of The ZrO₂/Al₂O₃ Composite Powder For Dental Applition

ZrO₂/Al₂O₃ composite porcelain has excellent biocompatibility and mechanical properties.It is a proper dental prosthetic materials.This study prepared an excellent ZrO₂/Al₂O₃ composite precursor powder by sol method.The crystal transfomation at different hot treatment temperature and different component ratio was examined.Also the mechanical properties of porcelain prepared by sol method and mechanical mixing method was studied.The reaction mechanism between zirconia and alumina was discussed.The ZrO₂/Al₂O₃ composite podwer was prepared by sol method.The effect of the concentration of inorganic precursors,dispersing agent,drying method and pH value on sol solution were studied.The proper conditions was confirmed.The dispersion of precursor composite powder was better at pH=9.0,1wt%PEG800+PEG2000,the inorganic precursors's concentration of 0.3mol/L,n-butanol azeotropic distillation,ammonia inverse titration method.The particles was spherical and the average particle size was 30nm.The effect of pH value,calcined temperature and ratio of ZrO₂/Al₂O₃ on the crystal was studied.The result showed:the t-ZrO₂ intensities increaseed with the pH values of sol solution and calcined temperature.Proper alumina can inhibit the growth of zirconia grain.With the relative content of alumina increased,the crystallization temperature of zirconia improved.The mechanical properties of porcelain prepared by sol method was better than that prepared by mechanical mixing method.The Sere and EDS analysis also indicates that the composition which prepareed by sol method distribution was more homogeneous.The composite porcelain of different ratio of ZrO₂/Al₂O₃ were prepared by composite powder from sol method.The composite porcelain with 50at%zirconia content has the best mechanical properties as calcined at 1450℃,the flexural strength, fracture toughness and hardness were 786MPa,8.3MPa·m^1/2 and 14.2GPa.It can satisfy the clinical treatment request.The surface morphology and fracture characteristics were examined by SEM and XRD.The results showed that the grains of zirconia and alumina were small and combined tightly.Zirconia stress-induced phase transformation toughening effect plays an important role in improving the composite material fracture toughness.The fracture mode of the composites was mainly intracrystalline fracture.In the research,the composites of ZrO₂/Al₂O₃ ceramic have fine physical,chemical properties and aesthetics effect.The bulk density is close to that of natural dental,and the strength and rigidity are higher than it.It can satisfy the mechanical property request and special application environment.