Plasma sprayed carbon nanotube and graphene nanoplatelets reinforced alumina hybrid composite coating with outstanding toughness

Role of the Hybrid Addition of Carbon Nanotubes and Graphene Nanoplatelets on the Corrosion Behavior of Plasma‐Sprayed Aluminum Oxide Nanocomposite Coating

“…The reasons mainly attributed for the increased mechanical properties are better dispersion of CNTs in Al 2 O 3 matrix and distinct toughening mechanisms like CNT bridging, crack deflection, and wetting of CNTs by Al 2 O 3 . Apart from CNTs, similar results were obtained in various researches based on the reinforcement of GNPs which is basically explained by a good interfacial bonding between GNPs and the parent matrix, crack bridging, as well as GNP pullout. However, the major drawback incurred during the incorporation of carbon nanofillers is related to their dispersion in the base matrix.…”

“…This did not only ensure the better dispersion of these carbon nanofillers in Al 2 O 3 by reducing the restacking and agglomeration of GNPs and CNTs, respectively, but also provided the benefits of 2D with 1D reinforcement which led to a further improvement in the desired properties. Mukherjee et al obtained an outstanding 200% enhancement in the relative fracture toughness in the CNT‐ and GNP‐reinforced Al 2 O 3 coating with respect to the base Al 2 O 3 coating which was assigned to the concurrent effect of increased densification with superior interface between the matrix and reinforcements and various toughening mechanisms provided by CNTs and GNPs . Apart from the plasma‐spraying technique, similar results were obtained for the Al 2 O 3 pellet reinforced with the same amount of reinforcement fabricated by hot pressing.…”

“…A brief information about the plasma‐sprayed coating deposited on the aluminum substrate, its cross‐sectional images, phase occurrence, and retention of carbon nanofillers have been included for the sake of completeness. In our earlier work, coating was deposited on stainless steel and the details of these coatings can be found in previous studies . Figure a shows the cross‐sectional images of the coatings.…”

“…Four different powder compositions, A‐, AC‐, AG‐, and ACG‐, were prepared via spray drying. Details of the powder treatment steps have been discussed in previous studies . Spray drying not only assisted in the homogenous dispersion of carbon nanofillers into the alumina matrix but also resulted in the formation of micrometer‐sized spherical agglomerates of 40–60 μm in diameter.…”

“…In the recent past, investigations have also been made on the effect of synergistic addition of both CNTs and GNPs in the Al 2 O 3 matrix . This did not only ensure the better dispersion of these carbon nanofillers in Al 2 O 3 by reducing the restacking and agglomeration of GNPs and CNTs, respectively, but also provided the benefits of 2D with 1D reinforcement which led to a further improvement in the desired properties.…”