Procédé de dépôt couplant un réacteur-injecteur et un plasma basse pression : vers le dépôt de couches minces multifonctionnelles pour l'aéronautique

In the aeronautic industry, icing appears over the airplane's surfaces at ground or in flight is a major problematic. One solution could be a passive solution by the use of antiicing coatings. One material wich could allow these properties and be sustainable for aeronautics is the nanocomposite. Nanocomposite (NC), i.e. coatings with nanoparticles (NP) embedded in a matrix develop multi-functional properties. This thesis develops and studies a novel, flexible and secure approach for the formation of nanocomposite coatings. Indeed, this process combines a reactor-injector and a plasma process. The reactor-injector is a liquid/gaz injection device in which is form small ZnO NP (Ø : < 10 nm) from the hydrolysis of an organometallic precursor. Hence, the control of the chemical reagents and the injection's parameters allows to form non-aggregates NP with small quantity of stabilizing agent. This technology called "reactor-injector" has been patented. For the formation of the nanocomposite coatings, the reactor-injector is combined with a low pressure plasma process. The plasma process will interact with the matrix precursor injected to form an embedment coating for the nanoparticles. The impact of the pulsed pressure injection over the low pressure plasma has been studied to understand the mechanics of the NP transport during the process. Thus, this process permits to limit the interaction between the user and the nanoparticles from their synthesis to their embedment. The characterisation of these coatings shows well dispersed and small ZnO nanoparticles with the combination of hydrophobicity and abrasion-resistant properties. Finally, this process is flexible and depending on the precursors allows the formation of differents NP (CuOx, WOx...) or matrix (a-CH,SiOx).Dans l'industrie aéronautique, la glace se formant sur la surface des avions au sol ou en vol est un problème majeur. Afin de résoudre ce problème, une solution passive pourrait être employé par un revêtement antigivre durable. Un matériau permettant d'obtenir ses propriétés tout en étant durable sur des avions est le nanocomposite. Le nanocomposite est un revêtement dans lequel des nanoparticules sont intégrées dans une matrice et permet de coupler les propriétés pour être multifonctionnel. Cette thèse développe et étudie un nouveau, sécurisé et flexible procédé pour la formation de revêtement nanocomposite. En effet, ce procédé combine un réacteur-injecteur et un procédé plasma. Le réacteur-injecteur est un injecteur de gaz/liquide dans lequel se forme des petites nanoparticules de ZnO (Ø : < 10 nm) par l'hydrolyse d'un précurseur organométallique. Dans cette thèse, nous montrons que le contrôle des réactifs chimiques et des paramètres d'injection permet la formation de nanoparticules non-agrégée avec une faible quantité d'agent stabilisant. Pour la formation de revêtement nanocomposite, le réacteur-injecteur est couplé avec un procédé plasma basse-pression. Ce procédé plasma interagit avec le précurseur de matrice injecté pour former la matrice recouvrant les nanoparticules. L'effet de l'injection pulsée sur le plasma basse pression a été étudié pour comprendre les mécaniques de transport des nanoparticules au cours du procédé. De plus, ce procédé permet de limiter les interactions entre l'utilisateur et les nanoparticules de leur synthèse à leur incorporation dans le revêtement. La caractérisation de ces revêtements montre de petites nanoparticules dispersées de façon homogène avec la combinaison de propriétés hydrophobes et de résistance à l'abrasion. Au final, ce procédé est montré comme flexible car en fonction des précurseurs utilisés, il est possible de former différents types de nanoparticules (CuOx, WOx...) ou de matrice (a-CH, SiOx)

Deposition method combining a reactor-injector and a low pressure plasma process : towards polyvalent thin films for aeronautic

Dans l'industrie aéronautique, la glace se formant sur la surface des avions au sol ou en vol est un problème majeur. Afin de résoudre ce problème, une solution passive pourrait être employé par un revêtement antigivre durable. Un matériau permettant d'obtenir ses propriétés tout en étant durable sur des avions est le nanocomposite. Le nanocomposite est un revêtement dans lequel des nanoparticules sont intégrées dans une matrice et permet de coupler les propriétés pour être multifonctionnel. Cette thèse développe et étudie un nouveau, sécurisé et flexible procédé pour la formation de revêtement nanocomposite. En effet, ce procédé combine un réacteur-injecteur et un procédé plasma. Le réacteur-injecteur est un injecteur de gaz/liquide dans lequel se forme des petites nanoparticules de ZnO (Ø : < 10 nm) par l'hydrolyse d'un précurseur organométallique. Dans cette thèse, nous montrons que le contrôle des réactifs chimiques et des paramètres d'injection permet la formation de nanoparticules non-agrégée avec une faible quantité d'agent stabilisant. Pour la formation de revêtement nanocomposite, le réacteur-injecteur est couplé avec un procédé plasma basse-pression. Ce procédé plasma interagit avec le précurseur de matrice injecté pour former la matrice recouvrant les nanoparticules. L'effet de l'injection pulsée sur le plasma basse pression a été étudié pour comprendre les mécaniques de transport des nanoparticules au cours du procédé. De plus, ce procédé permet de limiter les interactions entre l'utilisateur et les nanoparticules de leur synthèse à leur incorporation dans le revêtement. La caractérisation de ces revêtements montre de petites nanoparticules dispersées de façon homogène avec la combinaison de propriétés hydrophobes et de résistance à l'abrasion. Au final, ce procédé est montré comme flexible car en fonction des précurseurs utilisés, il est possible de former différents types de nanoparticules (CuOx, WOx...) ou de matrice (a-CH, SiOx).In the aeronautic industry, icing appears over the airplane's surfaces at ground or in flight is a major problematic. One solution could be a passive solution by the use of antiicing coatings. One material wich could allow these properties and be sustainable for aeronautics is the nanocomposite. Nanocomposite (NC), i.e. coatings with nanoparticles (NP) embedded in a matrix develop multi-functional properties. This thesis develops and studies a novel, flexible and secure approach for the formation of nanocomposite coatings. Indeed, this process combines a reactor-injector and a plasma process. The reactor-injector is a liquid/gaz injection device in which is form small ZnO NP (Ø : < 10 nm) from the hydrolysis of an organometallic precursor. Hence, the control of the chemical reagents and the injection's parameters allows to form non-aggregates NP with small quantity of stabilizing agent. This technology called "reactor-injector" has been patented. For the formation of the nanocomposite coatings, the reactor-injector is combined with a low pressure plasma process. The plasma process will interact with the matrix precursor injected to form an embedment coating for the nanoparticles. The impact of the pulsed pressure injection over the low pressure plasma has been studied to understand the mechanics of the NP transport during the process. Thus, this process permits to limit the interaction between the user and the nanoparticles from their synthesis to their embedment. The characterisation of these coatings shows well dispersed and small ZnO nanoparticles with the combination of hydrophobicity and abrasion-resistant properties. Finally, this process is flexible and depending on the precursors allows the formation of differents NP (CuOx, WOx...) or matrix (a-CH,SiOx)

Electrical and optical characterization of a capacitively-coupled RF plasma with a pulsed argon gas injection

International audienceNanocomposite thin film deposition using a reactor-injector of nanoparticles implies a pulsed gas injection. In a plasma, this can affect the behavior of the downstream process. Here, the case of an asymmetric low-pressure RF plasma with a pulsed argon gas injection is analyzed by electrical and optical emission spectroscopy measurements. It is found that this injection mode can highly affect the plasma stability: both the electron temperature and density are modified during the rise and the decrease of the gas pressure. A new injection mode combining continuous and pulsed injections is proposed to obtain more stable conditions

Soft polymerization of hexamethyldisiloxane by coupling pulsed direct‐liquid injections with dielectric barrier discharge

International audienceThis work examines the combination of pulsed direct-liquid injections with dielectric barrier discharge at atmospheric pressure for the deposition of organosilicon coatings using hexamethyldisiloxane (HMDSO) as the precursor and nitrogen as the carrier gas. In such conditions, deposition relies on the charging of micrometer droplets and their transport toward the substrate by the Coulomb force. The thin-film morphology and extent of precursor fragmentation are strongly linked to the amount of energy provided by the filamentary discharge to HMDSO droplets. While cross-linked and smooth coatings were achieved at low energies as in standard gas phase plasma polymers, viscous and droplet-like structured thin films were deposited at higher energies. The latter material is attributed to the soft polymerization of HMDSO droplets related to plasma–droplet interactions

PE-CVD with organometallic precursors: contribution of aerosol assisted processes

International audiencePE-CVD is widely used to deposit inorganic thin films. For example, a lot of different precursors (TEOS, HMDSO, HMDS, TMS, etc.) has been used for organosilicon or silica-like coatings. In contrast, only few studies are using organometallic precursors. Indeed, such molecules are generally unstable, pyrophoric and highly reactive with air and/or oxygen. Aerosol-assisted processes are able to avoid these problems. Indeed, diluted in organic solvents, it enables to inject droplets of organometallic precursor charged liquids. This contribution aims to report first results obtained with nickel-or zinc-based organometallic precursors. Using a pulsed injection of the liquid solution, it enables to deposit DLC matrices doped with Ni or Zn. Depending on the aerosol composition, the plasma behaviours as well as the film structures and properties will be discussed

Pulsed aerosol assisted plasma deposition: influence of the injection parameters on ZnO/DLC nanocomposite thin films

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Secured Nanosynthesis–Deposition Aerosol Process for Composite Thin Films Incorporating Highly Dispersed Nanoparticles

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Aerosol assisted atmospheric pressure plasma jet for a high deposition rate of silica-like thin films

International audienceThis paper investigated thin films deposition processes of silica-like based on the injection of liquid droplets in Atmospheric Pressure Plasma Jet–APPJ operated in open air. An aerosol of hexamethyldisilane is produced by a syringe-pump and injected in a nitrogen post-discharge for different liquid precursor and carrier gas flow rates. For high carrier gas flow, this process enables to form silica-like without addition of oxygen in the plasma phase. Furthermore, this process offers a thin film dynamic deposition rate from 500 to 1400 nm.m.min −1 depending on the carrier gas flow and the film structure departs from silica-like to organosilicon layers for the lowest flow rates. These evolutions are attributed to plasma–droplets interactions related to the transport of droplets, the evaporation of liquid and plasma polymerization

Time-Resolved Analysis of the Electron Temperature in RF Magnetron Discharges with a Pulsed Gas Injection

International audiencePulsed gas injection in a plasma can affect many fundamentals, including electron heating and losses. The case of an asymmetric RF magnetron plasma with a pulsed argon injection is analyzed by optical emission spectroscopy of argon 2p-to-1s transitions coupled with collisional-radiative modeling. For a fully detailed population model of argon 2p levels accounting for direct and stepwise electron-impact excitation in optically thick conditions, a rapid decrease in the electron temperature, Te, is observed during each gas injection with the sudden pressure rise. The opposite trend, with unrealistic Te values before and after each pulse, is observed for analysis based on simple corona models, thus emphasizing the importance of stepwise excitation processes and radiation trapping. Time-resolved electron temperature variations are directly linked to the operating parameters of the pulsed gas injection, in particular the injection frequency. Based on the complete set of data, it is shown that the instantaneous electron temperature monotonously decreases with increasing pressure, with values consistent with those expected for plasmas in which charged species are produced by electron-impact ionization of ground state argon atoms and lost by diffusion and recombination on plasma reactor walls

Secured Nanosynthesis–Deposition Aerosol Process for Composite Thin Films Incorporating Highly Dispersed Nanoparticles

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