Graphene Coating
Deposition of graphene as a coating material over large-scale areas is an intense topic of research because of complexities involved in the existing deposition techniques. Higher defects and compromised properties restricted in realizing the full potential of graphene coating. This work aims to deposit graphene coatings by adopting a traditional technique, that is, plasma spraying, which has inherent merits of extremely high cooling rate (∼106 K/s) and low plasma exposure time (∼0.1–10 μs). Graphene nanoplatelets (GNPs) were spray-dried into spherical agglomerates (∼60 μm dia.) and coatings were deposited over a wide range of surfaces.
Tailoring Wettability
In this study a simple, direct, one-step, scalable technique for instant tuning of all the different states of wetting characteristics using atmospheric plasma spray (APS) technique was used. We observed that, just by changing the process parameters in the APS technique, the wetting characteristics of an intrinsically hydrophilic aluminum metallic surface can be tuned to superhydrophilic (contact angle (CA: 0°), hydrophilic (CA: 19.6°), hydrophobic (CA: 97.6°), and superhydrophobic (CA: 156.5°) surfaces. Also, tuned superhydrophobic surface showed an excellent self-cleaning property. Further, we demonstrated that these surfaces retain their superhydrophobic nature
Thermal Barrier Coatings
Lanthanum zirconate (La2Zr2O7), an emerging candidate for TBC system, faces stringent concern owing to poor fracture toughness. We report an exceptionally high fracture toughness(5.3 ± 0.4 MPa m0.5) value for a La2Zr2O7 coating prepared by atmospheric plasma spray technique reinforced by carbon nanotubes (2 wt %); the enhancement in fracture toughness was noted to be more than 300% compared to all previous works. Several factors, viz. increased density, uniform distribution of CNTs in La2Zr2O7 matrix, stabilization of pyrochlore La2Zr2O7 phase and various associated toughening mechanism offered by CNTs.
Nitride Coatings
In this study in-situ fabrication of oxide-free titanium nitride (TiN) coating by conventional plasma spraying technique. Complete oxide free TiN coating without using low pressure or vacuum environment was achieved by using the N2 shroud with plasma spraying. X-Ray diffraction and Transmission electron microscope confirmed the absence of any traces of oxide in the coating. Coating showed exceptionally higher mechanical properties (H: ∼18 GPa; E: ∼317 GPa). Outstanding reduction of ∼15 times in wear rate and ∼4 times in corrosion rate was observed compared to bare substrate (i.e. Ti-6Al-4V).
Corrosion Resistant Coatings
In this study, article communicates the successful fabrication of plasma sprayed graphene nanoplatelets (GNPs) reinforced ceria (CeO2) composite coating. Later, various characterizations confirm the presence of survived GNPs into CeO2 matrix and its transformation to few layered graphene during plasma spraying. The reinforcement of GNPs led a significant enhancement in corrosion resistance and mechanical performance. Addition of 5 wt% GNPs in CeO2 displayed an exceptional reduction in corrosion rate about ∼15 times in 3.5 wt% NaCl solution, while superior improvement of 50% in hardness,.....
Wear Resistant Coatings
In this study, graphene nanoplatelets (GNPs: 1–2 wt. %) reinforced TiN coating were successfully fabricated over titanium alloy using a reactive shroud plasma spraying technique. All coatings were completely oxide free, while the addition of GNPs suppressed the non-stoichiometric TiN0.3 phase. Improvement of 19%, 18% and 300% in hardness, elastic modulus and fracture toughness was achieved by mere addition of 2 wt. % GNP. The addition of GNP in TiN also reduced the wear volume loss and the wear rate of the coatings for the entire range of temperature (293–873 K).
Ceramic Coating for Superior Water Treatment
This study addresses the critical issue of water scarcity by introducing a novel ceramic membrane fabricated through atmospheric plasma spraying (APS). These membranes exhibit impressive properties, including high water flux, excellent contamination rejection rates, low fouling, and mechanical robustness. The membranes are composed of YSZ and boast a unique structure with controlled porosity (30%) and small pore size (0.3–1.2 µm).
Composite Coating for Supercapacitor Applications
This study presents a synergistic electrode material by combining multi-walled carbon nanotubes (MWCNTs) with graphite nanoplatelets (GNPs) through a simple spray drying process. The resulting composite demonstrates enhanced electrochemical performance for supercapacitors. The uniform dispersion of CNTs prevents GNPs restacking, leading to increased surface area, porosity, and conductivity.
