An application of different types of chemical vapor deposition (CVD) reactors is reviewed for the coating of fine particles used for the production of functional materials. A new process of coating of fine particles in the form of agglomerates was developed in a moving-bed CVD reactor and discussed in some details. Then, the effect of the process conditions and the agglomerate structural parameters are examined by using a comprehensive mathematical model with the aim of maximizing the uniformity of coating deposits in the radial direction of the agglomerate at a desired quantity of deposit.  Finally, the mechanical and thermal properties of silicon nitride fine particles coated with aluminum nitride obtained by hot-press sintering are experimentally measured and compared with those of silicon nitride itself.