Comparative and Efficient Ammonia Gas Sensing Study with Self-assembly-Synthesized Metal Oxide-SiC Fiber-Based Mesoporous SiO Composites.

Self-assembled-assisted ternary nanocomposite InO-SiC, CuO-SiC, and MnO-SiC semiconductors were mixed with SiO to enable gas sensing using cyclic voltammetry. The results of TEM (transm InO-SiC-SiO ion electron microscopy), X-ray diffraction spectroscopy, and Raman spectra analysis affirm the closeness of few layers between SiO and SiC in InO-SiC, MnO-SiC, and CuO-SiC. Among the electrochemical impedance spectra curves of the nanocomposites, none of the samples had a semicircle profile, which indicates the existence of a higher charge-transfer resistivity behavior between the electrolyte and the sample electrode with charge carrier and transport effects, which is related to the well-developed porous structure of synthesized composites.

Novel preparation of functional β-SiC fiber based InO nanocomposite and controlling of influence factors for the chemical gas sensing.

The gas sensing ability of a pure β-SiC fiber is limited due to its low-sensitivity and selectivity with poor recovery time during a gas sensing test. The combination of functional β-SiC fibers with metal-oxide (MO) can lead to excellent electronic conductivity, boosted chemical activity, and high reaction activity with the target gas and β-SiC-InO sensor material. Influence factors such as amounts of MO, current collectors, and gas species (CO, O and without gas) for the gas sensing ability of β-SiC-InO nanocomposite were determined at standard room temperature (25 °C) and high temperature (350 °C) conditions.

Effect of Impurities Control on the Crystallization and Densification of Polymer-Derived SiC Fibers.

The polymer-derived SiC fibers are mainly used as reinforcing materials for ceramic matrix composites (CMCs) because of their excellent mechanical properties at high temperature. However, decomposition reactions such as release of SiO and CO gases and the formation of pores proceed above 1400 °C because of impurities introduced during the curing process. In this study, polycrystalline SiC fibers were fabricated by applying iodine-curing method and using controlled pyrolysis conditions to investigate crystallization and densification behavior.