Solution precursor plasma spraying (SPPS) was used to deposit barium magnesium tantalate thermal barrier coatings on titanium alloy substrates. The suspension was axially fed into an inductively-coupled RF plasma torch with a 25-mm converging nozzle. By selecting an atomization probe with a bimodal distribution of droplet size and adjusting the precursor feed rate and spraying distance, it was possible to tune the coating microstructure from dense splat-like layers to columns with intracolumnar porosity of 4.3% and intercolumnar porosity of 10%. The deposition rate achieved is suitable for commercial use.

This study assesses the microstructure and properties of SiC-based coatings deposited using liquid and gas-fueled HVOF spraying techniques and a recently developed SiC-YAG ceramic powder. The coatings are shown to be superior to plasma and high-frequency pulse deposition sprayed SiC in terms of density and microstructure and comparable in terms of adhesion values. SEM and EDX analysis of the coatings shows that hard SiC particles are retained in a YAG binder, forming a composite that exhibits good sliding wear and erosion behaviors. Due to its low density (< 4 g/cm 3 ), the SiC composite may be an alternative to coating materials such as WC-CoCr and Cr 3 C 2 -NiCr in weight-sensitive applications.

In this work, binder-free Co 3 O 4 films with in-situ oxygen vacancies are deposited in a one-step process by solution precursor plasma spraying (SPPS). It is believed to the first time Co 3 O 4 layers composed of hexagonal flakes were synthesized through the SPPS route. Specific capacitances up to 1700 F/g were obtained at a scan rate of 5 mV/sec, almost 97% of which was retained after 13,000 cycles at 20 mV/sec. This supercapacitor-like performance is attributed to the synergistic effects of a binder-free composition with in-situ oxygen vacancies and porous nanostructures.

In this work, suspension high-velocity oxyfuel spraying (SHVOF) with radial injection is shown to be a suitable technique for depositing graphene nanoplatelet layers on stainless steel substrates. The effect of feedstock injection parameters such as flowrate, injection angle, and position are investigated at different flame powers by means of high-speed imaging. In dry sliding wear tests, graphene layers on stainless steel exhibited a friction coefficient of around 0.1 after 1000 cycles and less than 0.3 after 2000 cycles. Compared to uncoated stainless steel, this is an order of magnitude improvement.

This paper describes the development of two iron-based alloys tailored for hardfacing applications typically fulfilled by Ni-WC overlay welding or laser cladding. The approach makes use of thermodynamic calculations and experimental testing to predict microstructure evolution during processing for different alloy compositions and how it is likely to influence final properties, specifically hardness and wear resistance.

This study assesses the durability of superhydrophobic surfaces that possess a scalable architecture similar in morphology to branching or corymbose coral. In the experiments, electrolytic copper powders with a coral-like morphology are cold sprayed onto metal, ceramic, and glass substrates, forming a textured copper layer with a structural hierarchy based on the morphology of the powder. After cold spraying, a flame treatment is applied, creating a porous layer of Cu 2 O over the pliable Cu surface, which further increases roughness. As a final step, a fluoroalkyl silane spray is applied to reduce surface energy. It is shown that the fluorinated surface retains its excellent water repellency after cyclic bending and folding, sand-grit erosion, knife-scratching, and even heavy loading with simulated acid rain. It also retains its adhesion to glass (17 MPa), ceramic (12 MPa), and metal (34 MPa) substrates.

This study assesses the influence of atmospheric plasma spraying parameters on splat stacking and porosity formation in bioglass coatings prepared from commercial powders. Coating samples were deposited on stainless steel substrates using spraying parameters established through numerical simulations. Different Ar-H 2 mixtures were used as the forming gas, and plasma current and spraying distance were varied. Coating microstructure and phase composition were determined by SEM and XRD analysis. Although numerical simulations for each parameter set predicted a suitable Sommerfeld number for proper splat stacking, Na 2 O and P 2 O 5 volatilization occurred during spraying, promoting the formation of porosity in the coatings. Denser coatings were obtained, however, by adjusting the gas mixture ratio, plasma current, and spraying distance such that enthalpy of the plasma jet is sufficient to overcome the glass transition temperature of the powder and at the same time avoid the evaporation of volatile oxides.