Nucleation and Growth of Si₂N₂O in Si₃N₄-Materials Employing Different Sintering Additives

Nucleation and Growth of Silicon Oxynitride Grains in a Fine‐Grained Silicon Nitride Matrix

“…This is consistent with the observation that ␣-Si 3 N 4 particles trapped in Si 2 N 2 O also serve as nucleation sites for Si 2 N 2 O. 15 The nucleation rate, or the probability that an embryo will attain a size which is bigger than a critical dimension for growth, depends on the degree of supersaturation of the liquid with (Si,O,N), in terms of n v in A and the viscosity locally surrounding that embryo, as seen from Eq. (2).…”

“…Si 2 N 2 O heterogeneously nucleates on ␤-Si 3 N 4 surfaces; thus it may be generally expected that there exists an epitaxial or a specific orientation relationship between ␤-Si 3 N 4 and Si 2 N 2 O. Based on morphological observations, Huang et al 18 15 also claim that trapping of ␣-Si 3 N 4 in Si 2 N 2 O is associated with heterogeneous nucleation of Si 2 N 2 O from the surface of ␣-Si 3 N 4 , and they have deduced a possible topotactical orientation relationship between ␣-Si 3 N 4 and Si 2 N 2 O. However, detailed examination of the crystal structural features of both ␣and ␤-Si 3 N 4 and Si 2 N 2 O indicates that, in excess of the dimensions of several Si-N rings, epitaxial bonding of Si 2 N 2 O on either ␣or ␤-Si 3 N 4 is impossible, because the bond angle will not match for long ranges.…”

“…38 larly trapped in Si 2 N 2 O grains possess a specific crystallographic orientation relationship with Si 2 N 2 O. 15,18 It can be further inferred that even if there is a partial ordering of liquid near the Si 3 N 4 -liquid interface in the form of Si 2 N 2 O, it may appear as small islands with the dimensions of several Si-N rings in Si 3 N 4 .…”

“…[8][9][10][11][12][13][14] In addition, OЈ-sialon phase also shows certain typical growth features such as development of elongated grains. [15][16][17] Thus, a material of fine-grained ␤-Si 3 N 4 dispersed with elongated Si 2 N 2 O grains may be obtained, such that it is microscopically analogous to the reinforcing of silicon nitride by elongated ␤-Si 3 N 4 grains, and functionally compatible with both thermal and mechanical properties. Contrary to extensive investigations and optimization of properties of composite systems based on ␣and ␤sialon, and the efforts of sintering bulk OЈ-sialons, [18][19][20] systematic investigation of composite systems based on ␤and OЈ-sialon phases has not yet been carried out.…”

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

“…Heterogeneous nucleation was described in the literature both for ␣ -SiAlON on ␣-Si 3 N 4 29 and ␤ -SiAlON on ␤-Si 3 N 4 . 30 Braue et al 31 reported on the heterogeneous epitaxy of silicon oxinitride, Si 2 N 2 O, on ␣-Si 3 N 4 .…”