General method for highly controlled preparation of ceramic hollow spheres from core‐shell structures

Abstract

The spouted bed chemical vapor deposition (CVD) technique have been successfully applied to prepare hollow spheres from core‐shell structures. The prepared SiC hollow spheres (SiC‐HS) showed the desired characteristic, such as pure phase (β‐SiC), uniform and concentrated distribution of diameter and sphericity. The flexibility of this method allows for independent control of the diameter, shell thickness and microstructures of the SiC hollow spheres. In particular, it is demonstrated that the precursor of SiC was carried by different carrier gas (hydrogen or argon), SiC‐HS with porous or dense shells can be obtained. The porous SiC‐HS have high density of stacking faults, which indicates that it can be used as photocatalytic materials. The dense SiC‐HS with high density (99%TD) exhibits excellent mechanical properties (average Young's modulus of 410 GPa and hardness of 42 GPa), and it can be used as fusion ignition target and encapsulation vessels as well. Through using different precursor, the spouted bed CVD technique used here could be generally adopted to synthesize other types (eg other carbides or complex oxides) of hollow spheres.