Microstructural Development in Silicon Nitride Ceramics

Microstructure and mechanical properties of silicon nitride ceramics prepared by pressureless sintering with MgO–Al2O3–SiO2 as sintering additive

“…23 Fig. 5 presents the SEM micrographs of fractured surfaces and polished and etched surfaces of Si 3 N 4 ceramics prepared by planetary ball-milling, respectively; while that for general ball-milling Si 3 N 4 were shown in Fig.…”

“…The growth kinetics of ␤-Si 3 N 4 grains in Si 3 N 4 ceramics containing a liquid phase have been studied by many researchers. [23][24][25][26][27][28][29] The ␣-␤ transformation is believed to occur after solution of fine ␣ grains and subsequent reprecipitation as ␤-phase in a liquid phase formed from the sintering additive. Table 1 shows the relative density and mechanical properties of Si 3 N 4 ceramics prepared by planetary high-energy ball-milling and sintered at 1780 • C for various soaking time.…”

Effect of Grain‐Boundary Phase on Dynamic Compression Fatigue in Hot‐Pressed Silicon Nitride

“…It is well established that the elongated ␤-silicon nitride grains are formed during the solution-diffusion-precipitation phase of the sintering process, and their growth is favored when the concentration of ␤ particles in the starting silicon nitride powder is decreased and the amount of sintering aid is increased. 18 The lattice image of CBP silicon nitride (see Fig. 2(a)) does not reveal any amorphous-phase grain-boundary triple points.…”

Variation of sintering parameters at an early stage of densification affecting β-Si3N4-microstructure

“…[23][24][25] Hampshire and Jack 26 investigated the influence of different sintering additives such as Y 2 O 3 and MgO on the development of the Si 3 N 4 microstructure. They reported that densification of Y 2 O 3 -doped Si 3 N 4 was mainly controlled by diffusion, while sintering MgO-doped Si 3 N 4 was predominately affected by the ␣-Si 3 N 4 -glass interface reaction.…”