Shu Xingsheng

Surface Modification of Nanometre Silicon Carbide Powder with Polystyrene by Inductively Coupled Plasma

An investigation was made into polystyrene (PS) grafted onto nanometre silicon carbide (SiC) particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency (RF) inductively coupled plasma (ICP) treatment of the nanometre powder. FTIR (Fourier transform infrared spectrum) and XPS (X-ray photoelectron spectroscopy) results reveal that PS is grafted onto the surface of silicon carbide powder. An analysis is presented on the effectiveness of this approach as a function of plasma operating variables including the plasma treating power, treating time, and grafting reaction temperature and time.

Microstructure, Hardness and Corrosion Resistance of ZrN Films Prepared by Inductively Coupled Plasma Enhanced RF Magnetron Sputtering

ZrN films were deposited on Si(111) and M2 steel by inductively coupled plasma (ICP)-enhanced RF magnetron sputtering. The effect of ICP power on the microstructure, mechanical properties and corrosion resistance of ZrN films was investigated. When the ICP power is below 300 W, the ZrN films show a columnar structure. With the increase of ICP power, the texture coefficient (Tc) of the (111) plane, the nanohardness and elastic modulus of the films increase and reach the maximum at a power of 300 W. As the ICP Power exceeds 300 W, the films exhibit a ZrN and ZrNx mixed crystal structure without columnar grain while the nanohardness and elastic modulus of the films decrease. All the ZrN coated samples show a higher corrosion resistance than that of the bare M2 steel substrate in 3.5% NaCl electrolyte. The nanohardness and elastic modulus mostly depend on the crystalline structure and Tc of ZrN(111).

Effect of Frequency on Emission of XeI* Excimer in a Pulsed Dielectric Barrier Discharge

Emission spectra of XeI* excimers and ultraviolet intensity at 253 nm from a dielectric barrier discharge (DBD) lamp excited by a pulsed voltage were measured as functions of pressure, electrical power, and frequency. In the DBD lamp driven by a higher frequency voltage, a more intense emission of XeI* excimers with high efficiency at 253 nm was found. A diffuse discharge mode was observed at high xenon pressure (>1 atm) with an excessive iodine concentration in the DBD driven by a high frequency (60 kHz) voltage.

Characteristics of Low Power CH4/Air Atmospheric Pressure Plasma Jet

A low power atmospheric pressure plasma jet driven by a 24 kHz AC power source and operated with a CH4/air gas mixture has been investigated by optical emission spectrometer. The plasma parameters including the electron excitation temperature, vibrational temperature and rotational temperature of the plasma jet at different discharge powers are diagnosed based on the assumption that the kinetic energy of the species obeys the Boltzmann distribution. The electron density at different power is also investigated by Hβ Stark broadening. The results show that the plasma source works under non-equilibrium conditions. It is also found that the vibrational temperature and rotational temperature increase with discharge power, whereas the electron excitation temperature seems to have a downward trend. The electron density increases from 0.8 × 1021 m−3 to 1.1 × 1021 m−3 when the discharge power increases from 53 W to 94 W.

Electrical Characteristics of Pseudoglow Discharges in Helium under Atmospheric Pressure

A pseudoglow discharge behaviour is achieved at a 2.0-mm dielectric-dielectric electrode gap in pure helium under atmospheric pressure. An experimental study of the pseudoglow discharges is presented. The electrical characteristics and the discharge photos of the pseudoglow discharges are analyzed and discussed. The current-voltage parameters of the pseudoglow discharges are considered in regard to the influence on their behaviour.

Deposition of Diamond Films on Copper Substrate

The direct deposition of diamond films on copper substrate has been suffered from adhesion problems due to the mismatch of the thermal expansion coefficients of diamond and copper. In this paper, nuclei with valuable density were directly introduced through a submicron diamond powder layer. The diamond grits partially were buried in the copper substrate leading to better adhesion. Another method with nickel intermediate layer for enhancing the adhesion was studied here in detail. It was suggested that Cu-Ni eutectic between the copper substrate and Ni interlayer might contribute to the adhesion improvement. The quality of the diamond films deposited with nickel interlayer was investigated by scanning electron microscopy and Raman spectroscopy.

Characterization of Carbon Deposits Formed During Plasma Pyrolysis of Xinjiang Candle Coal

Carbon deposits were formed on the reactor wall during plasma pyrolysis of the Xinjiang candle coal in our V-style plasma pyrolysis pilot-plant. The carbon deposits were studied using a scanning electronic microscope (SEM) and the X-ray diffraction (XRD) method. It was found that carbon deposits located at different parts in the reactor exhibited different microscopic patterns. The formation mechanism of the carbon deposits was deduced. The downward increase in the graphitization degree of the carbon deposits was found and interpreted.

Surface Modification of SiC Nanoparticles with PMMA by Low Temperature Plasma

An investigation into Poly (methyl methacrylate) (PMMA) grafted onto nano-SiC particles is reported in this study. In our experiment, the grafting polymerization reaction is induced by radio frequency (RF) discharge of N2 plasma treatment of the nanosized powder. FTIR (Fourier transform infrared spectrum), XPS(X-ray photoelectron spectroscopy) and TGA (Thermogravimetric analysis) results reveal that PMMA is grafted onto the surface of silicon carbide powder, and the crystal structure of the silicon carbide powder observed with XRD (X-ray diffraction) spectra is unchanged before and after the plasma graft polymerization.

Plasma Induced Grafting of PSt onto Titanium Dioxide Powder

An investigation of grafting of polymer of styrene (PSt) onto titanium dioxide powder is reported in this paper. The graft polymerization reaction was induced by N2 plasma treatment on the surface of titanium dioxide. Infrared (IR) spectra and X-ray photospectrum (XPS) results showed that PSt was grafted onto the titanium dioxide powder. An observation by X-ray diffraction (XRD) spectra indicated that the crystal structure of the titanium dioxide powder was unchanged after the plasma treatment.

Characteristics of RF Cold Plasma at Atmospheric Pressure

The characteristics of a stable discharge at atmospheric pressure is investigated. The plasma source consisted of two closely spaced parallel-plated perforated electrodes, driven by a radio frequency power to generate a uniform cold plasma in Helium at atmospheric pressure. Both alpha and gamma modes were clearly observed. The hollow cathode effects were found in the discharge. The influence of the dielectric barrier on the discharge was also investigated by utilizing a surface-anodized aluminium electrode as the anode.