A review of surface topographical modification strategies of 3Y-TZP: Effect in the physicochemical properties,microstructure, mechanical reliability,and biological response

The development of zirconia dental implants has become increasingly popular over the last years due to the outstanding mechanical properties, superior aesthetic appearance and high biocompatibility of this material. However, premature implant failure as a result of an incomplete osseointegration still represents a major concern. In this sense, surface modifications have been applied to dental zirconia to improve the biological interactions of the implant with the surrounding tissue. Nevertheless, surface modification of zirconia is challenging due to the formation of a monoclinic phase associated with ageing and loss of mechanical integrity. This review focuses on the most common surface topographical modification strategies currently applied to zirconia, namely grinding, sandblasting, chemical etching and laser treatment. A comprehensive and comparative analysis has been performed to assess the effects of these techniques on the physicochemical properties, mechanical performance, hydrothermal degradation behavior and biological response of the modified surfaces.     

A novel method to prepare self‐lubricity of Si3N4/Ag composite: Microstructure,mechanical and tribological properties

Si₃N₄/Ag composites were firstly prepared through SPS technology, using Si₃N₄ and AgNO₃ as raw materials. Utilizing the coordination bonding of Ag⁺ ions with nitrogen atoms of Si₃N₄, in situ generated Ag particles about 1 μm were tightly anchored on Si₃N₄ surface, thereby preventing the outflow of silver during sintering process. Meanwhile, smaller silver particles about 20 nm were located at the grain boundaries of Si₃N₄, which effectively improved the mechanical and tribological properties of Si₃N₄‐based composites. Finally, the Si₃N₄/Ag composites reinforced by Ag particles showed a friction coefficient of 0.48 ± 0.01, wear rate of 1.79 × 10^?6 mm³ N^?1 m^?1 and fracture toughness of 7.05 ± 0.2 MPa m^1/2, respectively.