配料Z值对常压烧结Sialon结构与性能的影响

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Effect of the value of feeding Z on the construction and properties of pressureless sintered Sialon ceramics

The general stoichiometrical composition of β′-Sialon is Si6-ZAlZOZN8-Z. Z changes from 0 to 4.2. The fabrication of Sialon involves complex physical and chemical reactions, so crystallized full density Sialon matericals can hardly be formated, and the value of Z is difficult to adjust precisely. The value of Z is a fundamental factor which decides the construction and main properties of pressureless sintered Sialon ceramics, such as lattice parameter, density, hardness, toughness, bending strength, et al. A Sialon ceramics with the relative density more than 99% and bending strength up to 612.2 MPa was prepared by pressureless sintering of the powder mixture of Si3N4, Al2O3, AlN and Y2O3. It was discovered that the Sialon prepared by the feeding value of Z=1, 2 had higher densification, and the bending strength increased exponentially with densities increasing. It was also discovered that lattice parameters (a) increased with Z value increasing.