Abstract
Details of the microstructure were investigated in Fe5Si3-particles-dispersed Si3N4 ceramics, synthesized by reaction during sintering. The following results were obtained: 1) the size of most part of Fe5Si3 particles was around 2 μm, and those particles had plate-like and roundish form, 2) a linear crack was observed along the boundary between Fe5Si3 particles and matrix. The width of the crack was approximately 10-25 nm, and this value was close to a calculated value considering the difference in thermal expansion coefficient of the two phases, 3) at the boundary of Fe5Si3 particles and matrix, there existed a glassy phase of about 2 nm in width, Si, Al, Y, O elements being detected in this phase, 4) around the Fe5Si3 particles, a Si2N2O phase with irregular shape formed; in this phase ultrafine particles with 50-100 nm were incorporated.
