Investigation of Ceramic-Matrix Nanocomposites via Metal Organic Chemical Vapor Deposition

摘要

The metal-organic chemical vapor deposition (MOCVD) conducted in fluidized bed was employed for the preparation of nano-sized ceramic-matrix composites. The metal-organic source was vaporized and then deposited onto ceramic-matrix powder surface. The composite powders were reduced in a gas mixture of H_2/N_2, and then sintered. In this study, two kinds of composites, Mo_5Si_3/Si_3N_4 and Cr_3C_2/Al_2O_3 were investigated. The XRD, SEM, and TEM were used to characterize the microstructure of samples at different processing stages. The mechanical properties of the composites were studied, too. Preliminary results indicate that the morphology of the initial deposition phase is amorphous with individual or island-like. Results also indicated that the mechanical properties of the sintered composite (only Mo_5Si_3/Si_3N_4 was presented) was improved by the incorporation of nano second phase.