The thick coatings obtained from nanostructured powders with fine layered microstructure are usually deposited using Air Plasma Spraying process (APS). In APS, nitrogen or argon gas is used as primarily. Microstructural characteristics of coatings for nanostructure powders are typically affected by the proportion of undissolved or partly melted zone (PM regions) present in coatings microstructure. It is observed that volume portion of partly melted regions is seen to be very much smaller in coatings obtained from nanostructurerd Al2O3-TiO2 powders deposited with nitrogen as compared to argon as the essential plasma gas. Coatings acquired from agglomerated powders of nanostructured alumina-titania shown to qualify superior resistance to wear over coatings by conventional powders. The Bi-modal representation of microstructures in nanostructured coatings with homogeneous dispersion of partially melted areas in fully melted region are considered to be responsible for improved properties of nanostructured coatings. This paper attempts to critically review the recent works done on atmospheric plasma sprayed nanostructured Al2O3-TiO2 coatings deposited by either argon or nitrogen as primary gas © 2019 Elsevier Ltd.