β-Si(3)N(4) Microcrystals Prepared by Carbothermal Reduction-Nitridation of Quartz

Single phase β-Si(3)N(4) with microcrystals was synthesized via carbothermal reduction-nitridation (CRN) of quartz and carbon coke powder as starting materials. The effects of reaction parameters, i.e., heating temperature, holding time, C/SiO(2) ratio, Fe(2)O(3) additive and β-Si(3)N(4) seeds on the phase transformation and morphology of products were investigated and discussed. Rather than receiving a mixture of both α- and β- phases of Si(3)N(4) in the products, we synthesized powders of β-Si(3)N(4) single polymorph in this work. The mechanism for the CRN synthesis of β-Si(3)N(4) from quartz and the formation mechanism of Fe(3)Si droplets were discussed. We also firstly reported the formation of Fe(3)Si Archimedean solids from a CRN process where Fe(2)O(3) was introduced as additive. Comparing to the gear-like short columnar morphology observed in samples without β-Si(3)N(4) seeding, the addition of β-Si(3)N(4) seeds led to an elongated morphology of final products and much finer widths. In addition, the β-Si(3)N(4) microcrystals exhibited a violet‒blue spectral emission range, which could be highly valuable for their future potential optoelectronic applications.