Controlling the number of excited atoms flowing into the reaction chamber using pulse-modulated induction thermal plasmas at atmospheric pressure

Abstract

Abstract.Controlling the number of excited atoms into a reaction chamber was investigated in Ar pulse-modulated induction thermal plasma (PMITP) with molecular gases at atmospheric pressure. Such control is important in promoting the modification of substrate surfaces in thermal plasma processing. The coil current required for sustaining a PMITP was modulated by setting the firing angle of the metal-oxidesemiconductor field-effect transistor (MOSFET) in the inverter power supply used as a high-frequency power source. The radiation intensities of the excited atomic lines were measured using the optical emission spectroscopy (OES) technique to estimate the number of excited atoms flowing into the reaction chamber. In particular, we found an increase in the number of excited Ar and H atoms flowing into the reaction chamber in Ar or Ar-H 2 PMITPs as a result of the pulse modulation of the coil current.

Nanoparticle synthesis using high-powered pulse-modulated induction thermal plasma

“…The amplitude of the coil current sustaining induction thermal plasmas was modulated into a rectangular waveform in this work. The modulated coil current has modulation parameters such as the shimmer current level (SCL), the on-time, and the off-time [23,24]. Figure 2 presents a definition of the modulation parameters.…”

A method for large-scale synthesis of Al-doped TiO2nanopowder using pulse-modulated induction thermal plasmas with time-controlled feedstock feeding

“…The PMITP was developed by our group to control the temperature and chemical activity fields in thermal plasmas using coil-current modulation [23,24]. In addition to this, our group recently developed a method for feedstock powder injection, in which the feedstock powder is supplied intermittently to the thermal plasma periodically, in synchronization with the coil-current modulation of the PMITP.…”

Influence of coil current modulation on TiO2 nanoparticle synthesis using pulse-modulated induction thermal plasmas

“…We have developed some high-power modulated induction thermal plasma systems, known as PMITP and AMITP [12,13]. The pulse-modulated induction thermal plasma (PMITP) system can modulate the coil current sustaining the induction thermal plasma into a rectangular waveform.…”

“…The pulse-modulated induction thermal plasma (PMITP) system can modulate the coil current sustaining the induction thermal plasma into a rectangular waveform. It can change the temperature and radical densities as well as the gas flow field in the thermal plasma in a time domain [12]. Some studies have tried to adopt the PMITP for surface modification of materials using good controllability of the temperature and radical densities [14,15,16] A high-power arbitrary-waveform-modulated induction thermal plasma (AMITP) system has also been developed for additional enhancement of the degrees of freedom in thermal plasma control [13].…”

“…The amplitude of the coil current sustaining induction thermal plasmas was modulated into a rectangular waveform in this work. The modulated coil current has modulation parameters such as the shimmer current level (SCL), the on-time, and the off-time [12]. Fig.…”