Dispersion of Cerium‐Based Nanoparticles in an Organosilicon Plasma Polymerized Coating: Effect on Corrosion Protection

306

327

Over the last ten years, expansion of atmospheric pressure plasma solutions for surface treatment of materials has been remarkable, however direct plasma technology for thin film deposition needs still great effort. The objective of this paper is to establish the state of the art on scientific and technologic locks, which have to be opened to consider direct atmospheric pressure plasma‐enhanced chemical vapor deposition (AP‐PECVD) a viable option for industrial application. Basic scientific principles to understand and optimize an AP‐PECVD process are summarized. Laboratory reactor configurations are reviewed. Reference points for the design and use of AP‐PECVD reactors according to the desired thin film properties are given. Finally, solutions to avoid powder formation and to increase the thin film growth rate are discussed.

Section: Chemistry and Precursor Depositionmentioning

confidence: 99%

Section: Chemistry and Precursor Depositionmentioning

confidence: 99%

Atmospheric Pressure Low Temperature Direct Plasma Technology: Status and Challenges for Thin Film Deposition

Massines

Sarra-Bournet

Fanelli

et al. 2012

306

327

“…Recently, a growing interest for multifunctional coatings has appeared with the development of nanocomposites thin films that consist of NPs embedded in a matrix. The presence of NPs provides the nanocomposite with extra properties related to their interactions with the matrix . In the literature, two approaches exist for synthesizing nanocomposite thin films using atmospheric pressure DBDs.…”

Section: Introductionmentioning

confidence: 99%

Control of composite thin film made in an Ar/isopropanol/TiO₂ nanoparticles dielectric barrier discharge by the excitation frequency

Brunet

Rincón

Martinez

et al. 2017

The synthesis of composites thin films made by injecting an aerosol suspension of 20 nm‐size TiO2 nanoparticles (NPs) and isopropanol (IPA) in a filamentary argon Dielectric Barrier Discharge (DBD) is studied as a function of the DBD frequency from 1 to 50 kHz. The plasma is modulated to get homogeneous coatings. The deposition rate and morphology of the composite thin films are determined from SEM images of both surface and cross section. Their chemical composition is investigated by XPS, Raman spectroscopy and FTIR measurements. The structural composition of the NPs is examined by XRD. All the deposited composites show the chemical signature of the NPs as well as of the polymer‐like coating resulting from the plasma polymerization of IPA. No mixed phase is observed and the sizes of the NPs as well as of their aggregates are not affected by the plasma. With this method aerosol droplets are evaporated before entering the plasma and the NPs inside a same droplet are aggregated. Results show that the DBD frequency controls the composite composition by independently influencing the NPs transport and the matrix growth rate. At 1 kHz, the coating is essentially made of NPs with a low carbon coating. From 1 to 50 kHz, the Ti/C ratio is divided by two orders of magnitude. As the frequency increases the quantity of NPs decreases and since 10 kHz the matrix thickness increases. The decrease of the NPs is explained by the numerical modeling of the NPs trajectory. It is found that from 10 to 1 kHz, the lower is the frequency, the higher is the transport of the NPs to the surface due to the electrostatic force. On the other hand the matrix growth rate increases from almost zero at 10 kHz up to 19 nm · min−1 at 50 kHz because of the linear increases of the DBD power with the frequency.

“…Introducing directly NPs makes possible to choose their size and shape, which allows a better control of the final nanocomposite properties . The feasibility of this approach at atmospheric pressure was demonstrated by Bardon et al who improved anti‐corrosion properties by incorporating aluminum‐cerium oxide NPs into a polymer matrix. Fanelli et al used ZnO NPs to create superhydrophobic organic‐inorganic nanocomposite thin films.…”

Section: Introductionmentioning

confidence: 99%

“…This system allows the transport of droplets with size <40 µm. On the other hand, an atomizer was used by Bardon et al and Fanelli et al In this work, a combination of a nebulizer and of a spray chamber was employed to select the smallest droplets (∼ 5–10 µm) before entering the plasma…”

Section: Introductionmentioning

confidence: 99%

Deposition of homogeneous carbon‐TiO₂ composites by atmospheric pressure DBD

Brunet

Rincón

Margot

et al. 2016

Atmospheric pressure Dielectric Barrier Discharge (AP‐DBD) was used to deposit homogeneous carbon‐TiO2 composites. Non‐intrusive Laser Light Scattering was employed to study the transport of the nanoparticles across the plasma. The characteristics of the coating were found to depend on the gas flow and on the spray chamber used for introducing the nanoparticles (cyclonic and Scott spray chambers). According to the SEM images, higher gas flows favor the formation of more homogeneous coatings both in terms of thickness and NPs‐aggregates distribution regardless of the spray chamber. The Scott spray chamber was shown to be more efficient for the deposition of uniform coatings even at low gas flows. It also yields the highest Ti concentration that reaches up to 18%. Furthermore, the light scattered by the nanoparticles was shown to be directly related to the coating thickness, hence to the density of nanoparticles in the plasma.