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Tungsten Inert Gas Welding
Published in P. Chakravarthy, M. Agilan, N. Neethu, Flux Bounded Tungsten Inert Gas Welding Process, 2019
P. Chakravarthy, M. Agilan, N. Neethu
Since the development of TIG welding, several improvements have been made to the process and its equipment. Certain welding power sources have been developed specifically for this process which includes pulsed DC and variable-polarity AC power source. Water-cooled and gas-cooled torches were also developed. The tungsten electrode is alloyed with small amounts of active elements to improve its emissivity, arc initiation, arc stability and electrode life. Various compositions of shielding gas mixtures were investigated and found to have better performance. Areas such as automatic controls, current pulsing, arc length controls etc. are still being actively studied.
Observation of ring–shaped pulsed DC discharge plasma source using single pole magnet setups for material processing
Published in Radiation Effects and Defects in Solids, 2019
Md. Amzad Hossain, M. A. Majed Patwary, M. M. Rahman Bhuiyan, Yutaro Nakamura, Kosei Sugawara, Yasunori Ohtsu
Pulsed DC discharge plasma is considered as an alternative technique to the RFMS method and supposed to be a simple and cost-effective deposition system that can be used to improve film properties as compared with widely used RFMS method (21–23). In a pulsed DC discharge plasma source, the pulsed DC power supply is a significant component for the reason that it may be possible to change the gas phase chemistry, the energy of the incident ions bombardment on substrate, the electron density, the electron temperature to meet the requirements of highly selective deposition method by changing the pulse duration and frequency (24–26). However, most of the models of commercially available pulsed DC discharge power supplies are expensive and custom-made which led to less flexibility to control pulse conditions. A number of researchers reported the pulsed DC discharge power supplies system mentioning different techniques (27,28). In comparison with RF power supplies, the pulsed DC discharge sources possess a considerably higher efficiency, a lower cost, a considerably simplified tuning and controlling (20,21). However, until now the medium-frequency pulsed discharges are much less studied than radio-frequency or direct current ones that impede essentially the progress in this area (21,28).