On the Interaction of a Microwave Excited Oxygen Plasma with a Jet of Precursor Material for Deposition Applications

Abstract

<p>A plasma source based on a microwave discharge at atmospheric pressure is used to produce an oxygen plasma torch. An admixture of liquid precursor material is evaporated and injected into the torch through a nozzle, causing oxidization and deposition of doped silica at a nearby quartz substrate. The temperature generated inside the plasma source and in the plume, in the region of treatment, and at the substrate surface are key parameters, which are needed for process description and optimization of plasma-chemical reactions.</p><p>Optical emission spectroscopy, high-speed imaging, and thermography were applied to observe and to characterize the jet behavior and composition. The experimental results are compared with self-consistent modeling.</p>

The effect of oxygen admixture on the properties of microwave generated plasma in Ar–O2: a modelling study

“…Without this reaction the gas becomes largely overheated even at low oxygen concentration. This contradicts experimental temperature values between 3000 and 4000 K observed outside the discharge tube [11]. Such an effect cannot be obtained in the models [19,20], because they omitted the heat balance of the discharge and use given values of the gas temperature.…”

“…An increase of the gas temperature is expected with the increase of the oxygen admixture. Values between 3000 and 4000 K have been obtained outside the plasma torch in experiments with flow rates between 16 and 18 slm [11] and oxygen concentration up to 75%. Therefore, for the sake of staying at real working conditions, further results are presented for a flow rate of 16 slm.…”

“…The role of the negative ions O − and O − 2 has been studied by modelling and experiments [5][6][7]. Experimental investigations on microwave driven discharges in Ar-O 2 gas mixtures are scarce and available mostly at low pressure [8][9][10][11]. While spatially resolved models with various degree of complexity are available for argon at low and atmospheric pressure (e.g.…”

Plasma‐based VAD process for multiply doped glass powders and high‐performance fiber preforms with outstanding homogeneity

“…A more detailed description of the system and its optimization has been provided recently. [ 25,26 ]…”