Si3N4/Si2N2O相界面结合力及结构特征OA

Silicon nitride ceramics exhibit excellent properties and have been widely used in equipment manufacturing and national defense industries.In order to further improve the mechanical properties of silicon nitride,it is necessary to have a better understanding of phase boundary structures and characteristics.This will provide basic knowledge for the R&D of high performance silicon nitride ceramics.Therefore,the Si3N4/Si2N2O phase boundaries in a hot isostatically pressed silicon nitride ceramic ball were observed and characterized using transmission electron microscope,by which the multiple structures of Si3N4/Si2N2O phase boundaries were constructed.The methods of near row matching and planar coincident site density were employed to analyze the structural characteristics of the constructed Si3N4/Si2N2O phase boundaries.The tensile properties of the phase boundaries were studied by molecular dynamic simulations.The results demonstrate that well-developed Si2N2O grains form tightly bonded with Si3N4 grains,exhibiting ordered atomic matching and high planar coincidence site density at the boundary.The orientation relationships are determined to be[0 0 0 1]//[0 0 1]and(1 0 (1) 0)//(0 1 0).Notably,the Si3N4/Si2N2O phase boundary with(1 0 (1) 0)/(0 1 0)matching shows superior performance,demonstrating higher separation work and greater tensile stress resistance compared to other phase boundaries.These findings reveal that the Si3N4/Si2N2O phase boundary with(1 0 (1) 0)/(0 1 0)matching represents a low-energy,stable configuration in silicon nitride ceramics.To increase the population of(1 0 (1) 0)/(0 1 0)phase boundary is good for the improvement of mechanical performance of silicon nitride.