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A modified sol–gel method is proposed for the preparation of silicon carbide ultrafine powders. In this method, tetraethoxysilane (TEOS) and saccharose are used for preparing a binary carbonaceous silicon xerogel, and ferric nitrate is employed in the sol–gel process as a catalyst. The influence of processing parameters such as temperature of reaction and mass ratio of C to Si (C/Si =0.5, 0.7, 1) on the synthesis of SiC particles were studied. After purification, the SiC sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectrum, Fourier transform infrared spectroscopy, differential thermal analysis (DTA) and thermo- gravimetric analysis (TGA). The results show that the SiC ultrafine particles were fully formed at reaction temperature of 1450 °C by employing the mass ratio of C/Si =1. This is confirmed by the obtained pattern from XRD and the Si–C absorption bands of SiC in the FTIR.

Crystalline silicon nitride (Si 3 N 4 ) wires have been synthesized by means of ball milling and nitridation route. The influence of temperature of reaction and starting condition of the powder (milled or unmilled) on the synthesis of Si 3 N 4 wires were studied. The reduced size of silicon particle during the milling process led to an increased degree of nitridation. Silicon powders with higher surface energy can react incessantly with nitrogen to form silicon nitride wires. The results show that the Si 3 N 4 was fully formed with two kinds morphologies including globular and wire with a width of 100–300 nm and a length of several microns at temperature of 1300 °C for 1 h by employing the milled silicon powder. The infrared adsorption of wires exhibit absorption bands related to the absorption peaks of Si–N band of Si 3 N 4 .

Silicon nitride (Si3N4) wires have been prepared by means of carbothermal reduction followed by the nitridation (CTRN) of silica gel containing ultrafine decomposed saccharose. The influence of temperature of reaction and mass ratio of carbon to silicon $$ \left( \frac{C}{Si} \right) $$ on the synthesis of Si3N4 wires were studied. The presence of nitrogen gas in the pores of gel at high temperature starts the CTRN reaction leading to the formation of Si3N4 wires. The results show that the Si3N4 was fully formed with two kinds of morphologies including globular and wire with a width of 100–500 nm and length of several microns at sintering temperature of 1,400 °C by employing the mass ratio of $$ \frac{C}{Si} \; = \;0.5 $$ . The infrared adsorption of the wires exhibits absorption bands related to the absorption peaks of Si–N bond of Si3N4. The thermal analysis results reveal that carbothermal nitridation reaction was completed at temperature of 1,400 °C.

In this paper, uniform argon glow discharge at atmospheric pressure in a diffuse mode driven by a 300-W radio-frequency (13.56 MHz) power supply based on dielectric barrier discharge was investigated. In this work, the effect of the parasitic capacitor on the electrical characteristics of the capacitively coupled atmospheric pressure plasma was investigated. It was revealed that more than half of the RF current is parasitic in our system as a characteristic of the capacitively coupled plasma. It was also proved that the discharge resistance and sheath capacitance increase at higher input powers while the impedance decreases. In order to recognize plasma, optical emission spectroscopy apparatus was used. Argon, oxygen, copper, and nitrogen spectrum lines were diagnosed. The plasma gas temperature and electronic excitation temperature were investigated showing a non-equilibrium discharge.