Comparison of Silicon Nitride Nanofibers Synthesized Using Silica Nanopowders and Silica Gel

Abstract

Nanofibers of alpha silicon nitride were grown by a vapor-solid mechanism at 1450˚C, through the carbothermal reduction process. Two different precursor silica sources were used: silica nanopowders and silica gel. The effect of processing geometry, particularly the stacking orientations of the graphite substrates, silica pellets, and crucibles, on the density of nanofiber growth was also explored. The silicon nitride nanofibers appear with a predominantly rectangular cross section from silica nanopowder precursors and with a circular cross section for silica gel precursors. Silica gel precursors produce nanofiber products that are smaller in cross section but greater in length than the products from silica nanopowder precursors. The processing geometry must be suitably designed such that the vapor-solid mechanism that is responsible for the formation of the nanofibers is not disrupted.

Processing and Characterization of Silicon Nitride Nanofiber Paper

“…Arik [9] and Wu et al [10] too have used this method. In another recent effort, Deshmukh et al [20] fabricated silicon nitride nanofibers using carbothermal reduction with silica gel and silica nanopowders as precursors.…”

Recycling of waste flat glass in the fabrication of Si3N4 powder by the carbo‐thermal reduction and nitridation

“…Application of high-energy milling, synthesizing precursors (eg, solution combustion) and direct supply of the nano size SiO 2 are examples of the studies using a specific SiO 2 source. 8,24,26,29,30 Waste glass eliminated the necessity of these types of SiO 2 source and offered a cost-effective starting material for the production of value-added ceramic powder.…”

“…8,24,26,29,30 Waste glass eliminated the necessity of these types of SiO 2 source and offered a cost-effective starting material for the production of value-added ceramic powder. One critical property was the size of SiO 2 , as it is reduced from micron to nano scale, the yield of Si 3 N 4 increases, reaction temperature lowers and morphology of Si 3 N 4 can be tailored.…”

Fabrication and Characterization of Short Silicon Nitride Fibers from Direct Nitridation of Ferrosilicon in N2 Atmosphere

“…Silicon nitride fibers were synthesized from the PCS by pyrolysis in ammonia gas atmosphere as early as in 1980s [ 7 , 8 ]. Si 3 N 4 fibers, nanowires and nanobelts can also be synthesized via carbothermal reduction and nitridation of diatomaceous earth [ 9 ] or rice husk ash [ 10 ] or silica nanopowders and silica gel [ 11 ], laser assisted chemical vapor deposition (LCVD) process [ 12 ], Ni-catalyzed chemical vapor deposition (CVD) process [ 13 ], directly reaction between silicon and ammonia [ 14 ] or with catalyst assist [ 15 ].…”