Skip to Main content Skip to Navigation
Theses

Microdécharges dans l'heptane liquide : caractérisation et applications au traitement local des matériaux et à la synthèse de nanomatéraux

Abstract : In this document, we report our work on discharges in heptane. One of the specific conditions selected is the choice of a micrometric gap distance. Typically, gaps were between 10 and 150 µm, corresponding to breakdown voltages between 1 and 15 kV. From breakdown up to 1 µs, the plasma discharge was characterized by shadowgraphy and optical emission spectroscopy (OES). Shadowgraphy results showed that the velocities of shock wave and bubble interface are about 1200 m s-1 and 100 m s-1, respectively. Beyond 1 µs, experimental and theoretical studies of the oscillatory dynamics of the bubble are made. Then, we proposed a new method to estimate the pressure at discharge breakdown. The technique is based on the response of a 'test bubble' present in the acoustic field of a new discharge whose pressure is to be known. It is estimated to be about 80 bar. OES, between 300 and 800 nm, showed a dominance of continuous radiations during the first 200 ns which were attributed to electron-ion recombination processes. Beyond 200 nm, continuous radiations collapse and then, the emission lines dominate the spectrum. The study of the H? line broadening showed that the electron density can reach 1019 cm-3. Regarding the interaction of the discharge with the electrode surfaces, we demonstrated that the diameter of the impact is governed by the quantity of charges deposited by the discharge. However, the impact morphology is determined by a balance between the force exerted by the plasma pressure and the Marangoni's force. Finally, we studied the possibility to synthesize platinum nanoparticles (5 nm in diameter) embedded in a matrix of hydrogenated carbon exhibiting a short range order
Complete list of metadata

Cited literature [41 references]  Display  Hide  Download

https://hal.univ-lorraine.fr/tel-01750216
Contributor : Thèses Ul Connect in order to contact the contributor
Submitted on : Thursday, March 29, 2018 - 12:40:44 PM
Last modification on : Saturday, October 16, 2021 - 11:20:09 AM

File

DDOC_T_2013_0119_HAMDAN.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01750216, version 1

Citation

Ahmad Hamdan. Microdécharges dans l'heptane liquide : caractérisation et applications au traitement local des matériaux et à la synthèse de nanomatéraux. Autre [cond-mat.other]. Université de Lorraine, 2013. Français. ⟨NNT : 2013LORR0119⟩. ⟨tel-01750216⟩

Share

Metrics

Record views

124

Files downloads

493