“…Further, various crystals of α‐Si 3 N 4 , β‐Si 3 N 4 , SiC, δ‐Ni 2 Si, Si 2 N 2 O, and graphitic carbons were formed when being annealed at 1300°C for 2 h. The crystals were identified as α‐Si 3 N 4 (hexagonal, PDF‐83‐0700), β‐Si 3 N 4 (hexagonal, PDF‐83‐0701), Si 2 N 2 O (orthorhombic, PDF‐83‐2148), δ‐Ni 2 Si (orthorhombic, PDF‐73‐2092), SiC (hexagonal, PDF‐89‐2216), and graphitic carbon (hexagonal, PDF‐75‐1621). Similar to the study reported previously, the transition metals such as nickel, iron, and cobalt could promote the formation of crystals of α‐Si 3 N 4 , SiC, and graphitic carbons for the PDC microspheres at an annealing temperature lower that of pure ternary Si–C–N system.…”