## 3 Results and Discussion
### Ostwald Ripening Effect and Fluorine Activation Traction Mechanism  
The Ostwald ripening effect is a classic mechanism of crystal nucleation and growth, distinct from dissolution recrystallization. The process involves large-particle crystals with lower surface energy continuously merging with smaller-particle crystals. These smaller crystals via for growth and are subsequently fused by larger particles, resulting in the formation of larger crystals. The final crystal size increases through fusion and absorption, varying with the external energy supply. In the system, small ions and electrons continuously transfer from smaller nanocrystals to larger grains, ultimately forming stable crystals with specific morphologies and structures. The growth of large-sized flaky alumina crystal nuclei has been observed to confirm this mechanism. As the temperature increased, small beohmite crystal nuclei continuously fused into the flaky alumina precursor and eventually transformed into complete \(\alpha\)-phase alumina. Figure 6b illustrates that the larger flaky alumina crystals developed and fused with smaller ones on the (0001) crystal plane, enhancing the crystal thickness. Consequently, to achieve flaky alumina with a high diameter-to-thickness ratio, it is essential to suppress the surface activity of the (0001) crystal plane, inhibit fusion along the Z-axis, and promote rapid fusion and growth along the X- and Y-axes. \begin{table}
\begin{tabular}{c c c c c} \hline
**Item Category** & **Scheme 1** & **Scheme 2** & **Scheme 3** & **Scheme 4** \\ \hline B2 (g) & 17 & - & 25.5 & - \\ \hline B3 (g) & 25.5 & 25.5 & - & - \\ \hline P3 (g) & - & 17 & - & 25.5 \\ \hline N1 (g) & - & - & 17 & 17 \\ \hline Methyl Silicone Oil (g) & 7.5 & 7.5 & 7.5 & 7.5 \\ \hline
1/s Viscosity (104 mPa\(\cdot\)S) & 1.77 & 10.86 & 8.35 & 200.84 \\ \hline
10/s Viscosity (104 mPa\(\cdot\)S) & 1.30 & 7.83 & 2.86 & 145.23 \\ \hline Thermal conductivity (W/m\(\cdot\)K) & 1.6 & 2.0 & 1.4 & 1.9 \\ \hline \end{tabular}
\end{table} 
Table 2: Parameter test of flake alumina replacing spherical aluminum of the same size in the composite filler system. Figure 6: SEM images of the development of flaky alumina under the influence of fluoride ions. (**a**) and (**b**), respectively denote the fusion growth directions of distinct plate-like alumina crystal planes. The activation traction mechanism of fluoride ions was mentioned in many papers as playing an important role in the solid-state synthesis of alumina with special morphologies [21,22]. There were various theories regarding the mechanism of fluoride ions in the preparation of \(\alpha\)-Al\({}_{2}\)O\({}_{3}\) with unique morphologies. Our observations tended to support the activity theory of the intermediate gas compound AlOF proposed by [PERSON] [14] and the theory proposed by [PERSON] [10]. The isomorphism of AlF\({}_{3}\) and \(\alpha\)-Al\({}_{2}\)O\({}_{3}\) can reduce the nucleation barrier. Figure 6a confirms these statements, showing that several flaky alumina crystals fused and spliced on the (1010) plane to form larger crystals. The reason for this is the introduction of fluoride ions, which, on the one hand, generate the intermediate compound Al-O-F (as shown in the reaction formulas below), a stable gaseous substance that plays a crucial role in the homogeneous transformation of materials. On the other hand, the free sites in the lattice structure of the intermediate-phase alumina are occupied by Al-F-Al fluorine bridges formed between the two types of Al\({}^{3+}\) ions, derived from AlF\({}_{3}\) and transitional alumina lattices, respectively. Due to the presence of Al-F-Al bridged bonds, chemical bonds are weakened, reducing the nucleation energy of \(\alpha\)-Al\({}_{2}\)O\({}_{3}\) and thus lowering the temperature required for the transition from \(\gamma\)-Al\({}_{2}\)O\({}_{3}\) to \(\alpha\)-Al\({}_{2}\)O\({}_{3}\).