<p>The synthesis of SiC micro- and nanofibers by chemical vapor deposition (CVD) from methyltrichlorosilane CH₃SiCl₃ on highly porous nickel foam substrates (matrices) was examined. The synthesis was conducted over the temperature range 1000–1200°C for 10 to 60 min. The dependence of nickel foam pore filling on synthesis temperature and time was established. The time dependence of the substrate weight gain resulting from the deposition of SiC nanofibers at constant temperature was linear. The weight gain increased exponentially with temperature at fixed holding time. The effective activation energy of the process was estimated at E_a = 107 kcal/mol (447 kJ/mol). This corresponds to the case when the decomposition of methyltrichlorosilane and the nucleation and growth of the SiC crystalline phase as nanofibers are the limiting stages in the process. According to X-ray diffraction, the fibers have a cubic β-SiC structure with lattice parameter a = = 0.4349 nm. This is also confirmed by selected-area electron diffraction patterns for nanofiber clusters taken using transmission electron microscopy. Silicon carbide nanofibers with diameters ranging from 40 to 200 nm (depending on synthesis temperature) have smooth surfaces. Among the predominant cylindrical fibers, fibers with a triangular cross-section are also observed. The two types of SiC nanofibers differ by the presence of twins in the first case and polytypes and stacking faults in the second, which is confirmed by the characteristic striped contrast in electron microphotographs and by the regular shift of reflections and streaking in electron diffraction patterns. Recommendations are formulated for the use of these composite nanostructures, namely SiC nanofibers spatially distributed in the pores of nickel foam, as catalyst carriers, fine filters for liquids and gases, and matrices for polymer-based nanofiber-reinforced composites.</p>