Papers by Keyword: Optical Emission Spectroscopy

Abstract: This study presents a comparative evaluation of two widely used chemical analysis techniques: scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and spectrophotometry. SEM-EDX is renowned for its ability to provide qualitative and quantitative elemental analysis at microscopic levels, making it a powerful tool for material characterization. On the other hand, optical emission spectroscopy, which analyses the light emitted by excited atoms, is highly effective for the rapid and precise quantification of elements in various sample types, especially metals and alloys. The research aims to assess the effectiveness, accuracy, and applicability of these techniques, by analysing identical samples (welding wire) using both SEM-EDX and spectroscopy, this study highlights the strengths and limitations of each method. Key parameters such as sensitivity, detection and data interpretation are compared to provide a comprehensive understanding of their performance in chemical analysis.

Abstract: In the current advancing world, operability and ease in processability of a material define its selection criteria for the intended applications. Hence, the industrial applications requiring high temperature sustenance, strength and corrosion resistance desperately demand the materials which employ simple processing in an economical way. Contemplating last few decades, it has been discovered that industries like petrochemical, power generation, nuclear energy, etc. greatly relied on nickel-based alloys till Fe-Ni-Cr based alloys were not introduced. The usable components are obtained either in cast or wrought form as per requirements. Fully killed alloy, developed under controlled conditions with some precautions during the casting process can lead to sound casting. The current study adopts a novel preliminary approach to control the quality of cast UNS N08120 material and minimize the possibility of defect generation. The possible reasons behind cast defects and how they transform into intrinsic defects have also been discussed. Calcium-based fluxes are introduced to molten metal as a degassing agent for the elimination of lighter impurities and entrapped gases. By the addition of quicklime (CaO) as a flux material during the sand casting process, an attempt has been made to reduce the presence of gases and impurities by more than 80%.

Abstract: The DC glow discharge of nitrogen gas was carried out by 5 kV DC power supply, which was used to bias voltage between two parallel plate electrodes in the cylindrical glass tube chamber. The distance between two parallel plate electrodes was about 37.5 cm. The voltage was applied on these electrodes between 800 V to 1400 V. The nitrogen pressure in the cylindrical glass tube chamber was controlled by rotary pump and vacuum value. Optical Emission Spectroscopy (OES) was used to investigate the local emissivity of nitrogen glow discharge in the range between 200 and 1,100 nm. The spatial distribution of reactive species was measured at different nitrogen pressures from 0.15-1.90 mbar. These measurements were obtained to analyze the electron temperature. The effect of different nitrogen pressures was studied on the electron temperature and the configuration of nitrogen plasma. In the result, it was found that the plasma column increased with increasing the nitrogen pressure. The electron temperature was less than 0.8 eV.

Abstract: Copper oxide is a low cost material, easy process fabrication and sensitivity to ambient conditions. Therefore, it is a suitable p-type semiconductor oxides material to be used as a gas sensing material. In order to raise the sensitivity of the copper oxide gas sensor, study on the correspondence in between the coated thin film with coating parameters is an important part. In current study, optical emission spectroscopy is used to investigate the reactive magnetron sputtering plasma during the deposition of copper oxide thin film. The measurement point was focused at roughly 2cm above the substrate holder. The emission of copper, oxygen and argon in the reactive magnetron sputtering were observed at various plasma conditions. In general, the emission of copper, oxygen and argon increased when the discharge rf power is increased. On the other hand, oxygen line intensity was found to be excess when the oxygen flow rate is above 8sccm. The result suggests the best condition to deposit the copper oxide thin film using solid 3 copper target.

Abstract: Optimal operating parameters for the study of titanium-hydrogen system with the help of glow discharge optical emission spectroscopy have been selected. Hydrogen distribution from the surface to the depth in technically pure titanium alloy after electrochemical hydrogen saturation has been studied.

Abstract: In this study, we conducted experiments to investigate the electrical and optical characteristics of a non-equilibrium Ar-N2 plasma discharge at atmospheric pressure. To obtain the plasma discharge we used our indigenously designed plasma generating device named CAPPLAT (Cold Atmospheric Pressure Plasma Torch) which was manufactured by Cresur Corporation. The plasma discharge obtained with only Ar gas was quite filamentary. So, to achieve a homogeneous discharge N2 gas was admixed. The effects of different volumes of admixed N2 gas were also studied. The optical emission spectroscopy was used to study the active charged species in the plasma discharges. The further increased volume of N2 gas further suppressed the emission intensity of Ar metastables but at the same time the emission intensity of the second positive system of nitrogen molecules (N2(C3Πu) enhanced significantly. It can be concluded that in Ar- plasma discharge, argon metastables are the main energy carriers but when N2 gas is added to the feeding gas (Ar) for plasma generation, the second positive system of nitrogen molecules (N2(C3Πu) become the main energy carriers. On the other hand the addition of the N2 gas doesn’t change the electrical characteristics of plasma discharge significantly. To identify the effectiveness of the CAPPLAT as a tool for sterilization, highly environmental stress resistant bacterial (Bacillus subtilis) endospores were treated for different durations. We could successfully deactivate the population of 1.0X107 to 4.0X107 Bacillus endospores/ml. The details of this experiment are discussed in our next paper.

Abstract: The time-resolved optical emission spectroscopy of Ti-Al alloy plasma produced by the Nd:YAG high-power laser pulses with wavelength of 1064nm was investigated both in air and vacuum conditions. The comparative studies gave detailed insights that the plasmas produced in air were much hotter and denser. The quantitative descriptions indeed suggested that a cascade avalanche process would be happen followed by air plasma firstly, before the laser impacting the target surface. On the other hand, the laser energy may be considerably attenuated via hotter and denser plasma, the amount of laser energy on the target surface remarkably decreased in air condition. In addition, at high-power laser irradiance levels, there was an auto regulatory area near the target surface and the plasma parameters tend to be saturated

Abstract: Elemental identification of material is a prime most important in material science field. Electric discharge is used for material elemental identification with optical emission spectroscopy. During electric discharge machining between two electrodes plasma is generated which emits intense radiation in the UV-Visible region. The generated plasma captured by optical emission spectroscopic technique and elements are identified from recorded spectra by matching with standard NIST database. This method is simple, rapid, and inexpensive compared to all other elemental identification method. The elements of the metal, semiconductors, even insulators can be identified without much difficulty. The elemental identification of material has been investigated in macro and micro level.

Abstract: This work presents an electrical and optical emission diagnostics of radiofrequency (RF) magnetron discharge used for titanium deposition in argon (Ar) and methane (CH4) gas precursor. The plasma was produced in incident power and gas pressure ranges of 20-300W and 15-100mTorr, respectively. We have studied the influence of the system operation parameters (incident power, pressure, proportion of gas precursor) on the self- bias voltage (Vdc) and emission intensity IAr of Ar (750.3nm) line. The results obtained show that the pressure of the optimum operation of the magnetron discharge was around 30 mTorr when the incident power varied from 20 to 300W. The relationship between the intensity of IAr (750.3nm) line and the incident power was established.

Abstract: SiOF like films have been elaborated in microwave excited DECR plasma reactor (Distributed Electron Cyclotron Resonance) from a mixture of oxygen-hexamethyldisiloxane (HMDSO/O2) and CF4. The fluorine contents in the precursor mixture were adjusted by varying the CF4 gas flow ratio in the range of 10% - 70%. Optical emission spectroscopy (OES) and Fourier transform infrared (FTIR) have been used for the plasma diagnostic and the deposited films structure analysis, respectively. Actinometric technique was used to find trends in the concentrations of species present in the plasma. A large number of species have been detected, such as F, Si, O, C and H. Depending on the gas mixture composition, FTIR spectra revealed the presence of several chemical bonds such as Si-F and Si-O.