Synthesis of β-SiC hollow spheres with tunable shell thickness by in-situ carbothermal reduction

Hollow spherical SiC ceramics exhibit significant potential as multifunctional and structural materials. Herein, the β-SiC hollow spheres were synthesized by in-situ vapor-solid reaction (carbothermal reduction) between mesocarbon microbeads (MCMB) and SiO vapor generated from SiO powders, and subsequent removal of the residual carbon cores by oxidization. The diameter of SiC hollow spheres accurately inherits the size of pristine MCMB, demonstrating a shape memory effect. Meanwhile, the shell thickness of SiC hollow sphere can be autonomously regulated from 0.46 to 3.87 μm by adjusting the siliconization degree (corresponding to the content of SiO). In addition, a variety of characterizations were used to describe the phase and structure of SiC hollow spheres, confirming their high-purity. The SiC hollow spheres also exhibit a high specific surface area of 4.21 m 2 g −1 and good thermal stability. This technique presents a new paradigm in the preparation of hollow spheres.