Influence of Transferred Arc Plasma Melting Time on the Formation of Phase and Microstructure of Mullite-Zirconia Composite

Transferred arc plasma is an effective and simple technique to synthesis a high temperature reaction ceramic composite material. In this paper, 20 kW transferred arc plasma torch was used to synthesis mullite-zirconia composites through the solid-state reaction of 3:2 mole ratio of ball milled alumina and zircon powders.  Dissociation of zircon in a thermal plasma arc is utilized as to prepare mullite-zirconia composites. The ball milled samples are melted for 3, 6, 9 and 12 minutes in transferred arc plasma torch at 20 kW power level with 10 lpm of argon flow rate and cooled by air. The phase and microstructure of melted samples were determined from X-ray diffraction (XRD) and SEM images. The obtained results shows that the processing time significantly influence on the formation of phase and microstructure of the mullite- zirconia composite

Cold Atmospheric Pressure Argon Plasma Jet Assisted Degradation of Malachite Green (MG) Aqueous Solution

The oxidative degradation of cold atmospheric pressure plasma assisted degradation of malachite Green (MG) was investigated in this study. Cold atmospheric pressure plasma assisted MG degradation process was carried out as a function various plasma treatment time (05, 10, and 15 mins). The % of degradation and presence carbon content in the plasma treated MG was examined by UV-Visible spectroscopy (UV-Vis) and total organic carbon (TOC) analyzer. Optical emission spectrometer was used to identify formation of various reactive species during in situ plasma treatment. The higher degradation percentage of 90% was obtained after plasma treatment time of 15 min and value of TOC also found to decreased significantly with increasing plasma treatment time.  Toxicity of the plasma-treated MG aqueous solution samples was also examined by Staphylococcus aureus (S.aureus) bacteria

Studies on Modification of Surface Properties in Polycarbonate (PC) Film Induced by DC Glow Discharge Plasma

The polycarbonate film (PC) surface was treated using glow discharge low-pressure air plasma. The modified surface was characterized by contact angle, FTIR, XRD, AFM, and XPS analysis. The surface-modified samples were further investigated using T-peel test for technical applications. The surface energy of the sample was estimated by measuring contact angle. The results show that, after plasma treatment, the root mean square (RMS) roughness of PC film was gradually increased with exposure time. Plasma treatment modified the chemical composition of the polymer surface and it made the surface to be highly hydrophilic. It was found that the air plasma treatment increases the polar component of PC film

Influence of operating parameters on surface properties of RF glow discharge oxygen plasma treated TiO2/PET film for biomedical application

In this paper, a thin transparent titania (TiO2) film was coated on the surface of flexible poly(ethylene terephthalate) (PET) film using the sol–gel method. The surface properties of the obtained TiO2/PET film were further improved by RF glow discharge oxygen plasma as a function of exposure time and discharge power. The changes in hydrophilicity of TiO2/PET films were analyzed by contact angle measurements and surface energy. The influence of plasma on the surface of the TiO2/PET films was analyzed by atomic force microscopy (AFM) as well as the change in chemical state and composition that were investigated by X-ray photo electron spectroscopy (XPS). The cytotoxicity of the TiO2/PET films was analyzed using human osteoblast cells and the bacterial eradication behaviors of TiO2/PET films were also evaluated against Staphylococcus bacteria. It was found that the surface roughness and incorporation of oxygen containing polar functional groups of the plasma treated TiO2/PET films increased substantially as compared to the untreated one. Moreover the increased concentration of Ti3 + on the surface of plasma treated TiO2/PET films was due to the transformation of chemical states (Ti4 + → Ti3 +). These morphological and chemical changes are responsible for enhanced hydrophilicity of the TiO2/PET films. Furthermore, the plasma treated TiO2/PET film exhibited no citotoxicity against osteoblast cells and antibacterial activity against Staphylococcus bacteria which can find application in manufacturing of biomedical devices

Development of phosphor containing functional coatings via cold atmospheric pressure plasma jet - Study of various operating parameters

In this study, we deposited phosphorous containing functional coatings on the surface of polypropylene (PP) substrate by cold atmospheric plasma assisted polymerization using low temperature plasma jet. Triisopropyl phosphate (TIP) was used as precursor while the coating process was carried out as a function of deposition potential and monomer flow rate. The influence of various plasma polymerization operating parameters on the surface properties of functional coatings are examined by means of atomic force microscopy (AFM), Scanning electron microscopy (SEM) and X-ray photo electron spectroscopy (XPS). The reactive species involved during the in-situ polymerization were studied by optical emission spectroscopy (OES). The variation in hydrophilic properties of the surface coated film was investigated by measuring contact angle. Furthermore, the stability of post-plasma polymerized films was evaluated by measuring contact angle values 15 days after storing in various ambient conditions (air and distilled water). The characterization results clearly exhibited that phosphorus containing functional films could be successfully deposited on the surface of PP films and the retention of the functional groups could be tuned within the framework of the operating parameters

Dye wastewater degradation by the synergetic effect of an atmospheric pressure plasma treatment and the photocatalytic activity of plasma-functionalized Cu-TiO2 nanoparticles

In this paper, the photocatalytic activity of plasma-functionalized Cu-doped TiO2 nanoparticles (NPs) and the oxidization process of atmospheric pressure plasma jet were combined for the degradation of reactive red-198 (RR-198) in aqueous solution. The first part of the study was thus devoted to subject Cu-TiO2 NPs synthetized by the sol-gel method to various plasma treatments operating in air, argon, oxygen and nitrogen to improve their degradation efficiency. The physicochemical properties of the NPs were then assessed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) measurements. XRD results indicated the predominant presence of the anatase phase which is the most photoactive form of TiO2. The XPS analysis revealed that the different plasma treatments triggered the formation of oxygen vacancies, Ti3+ oxidation state and Cu2+ oxidation state on the surface of Cu-TiO2 NPs. These changes, known to prevent the recombination of electron-hole pair, have led to a reduction in the bandgap that was more pronounced for the N-2 plasma-treated NPs. The second part of the paper explored the actual degradation of RR-198 in aqueous solution by an Ar plasma treatment alone or combined with the plasma pre-treated Cu-TiO2 NPs. Optical emission spectroscopy (OES) and spectrophotometric analyses showed that the synergetic effect of Ar plasma and N-2 plasma-treated NPs produced the highest concentration of OH center dot radicals and H2O2 species which led to the highest RR-198 degradation efficiency. This was further confirmed by pH, electrical conductivity and total organic carbon (TOC) removal measurements. The degradation of RR-198 was determined using UV-Vis spectroscopy and high-performance liquid chromatography (HPLC). Overall, it can be concluded that plasma-assisted processes illustrated by a combination of a direct plasma treatment with plasma-functionalized Cu-TiO2 NPs can be used in various textile and pharmaceutical industries as a highly effective treatment of their effluents before discharging