Fig. 4

SEM images of (a) Si/Sr = 1, (b) Si/Sr = 1.1, (c) Si/Sr = 1.3 and (d) Si/Sr = 1.4 samples sintered at 1350 °C, and diagrammatic sketch of sintering process (e–h).

SEM images of (a) Si/Sr = 1, (b) Si/Sr = 1.1, (c) Si/Sr = 1.3 and (d) Si/Sr = 1.4 samples sintered at 1350 °C, and diagrammatic sketch of sintering process (e–h).