Sintering Y-TZP ceramic produced from plasmochemical powders

摘要

Results from studies of the microstructure, phase composition, and mechanical properties of Y-TZP-based ceramic fabricated by means of vacuum sintering of a powder having the composition ZrO_2 + 3 mol- percent Y_2O_3 obtained by decomposition of an aqueous solution of Zr and Y nitrates in a high-frequency discharge plasma are presented. Vacuum sintering is performed in a broad range of temperatures and broad range of holding times. Previously established data are compared with the properties of ceramic sintered in open air. It is determined that vacuum sintering produces denser and stronger ceramics, moreover, at a sintering temperature of 1750 deg C the resulting ceramic has a density close to the theoretical. The structure of the ceramic then lacks traces of spontaneous transformation from tetragonal phase into monoclinic phase upon cooling from the sintering temperature, despite the fact that its mean grain size reaches 4.6 mu m. The material thus produced possesses high strength (up to 1000 MPa) and high fracture toughness (up to 15 MPa centre dot m~(1/2)),