Mechanical Properties of Machinable Zirconia Dental Composites

摘要

Ca_3(PO_4)_2/ZrO_2 dental composite ceramics using for CAD/CAM system were prepared and the effects of weak phases on microstructures and mechanical properties were studied. The results showed that intergranular spreads happened with the increasing Ca_3(PO_4)_2 contents due to the discontinuity of weak interfaces between Zirconia and Calcium phosphate in matrix. So the flexural strength and hardness of the Ca_3(PO_4)_2/ZrO_2 composite ceramics were decreased effectively, which improved the machinability of the composites. On the other hand, strong interfaces between Zirconias increased the integrality of the ceramic structures. ZrO_2 composite Ceramics with 15 percent Ca_3(PO_4)_2 were sintered at 1350 deg C. The flexural strength is 300.44MPa, fracture toughness is 4.36 MPam~(1/2), and hardness is 6.69 GPa. The cutting exponent of the Ca_3(PO_4)_2/ZrO_2 composite ceramics is obviously lower than that of the common commercial Vita Mark II and Dicor MGC ceramics, which shows good mechanical properties and machinability.