Ceramic Metastable Powder through Plasma Spraying

Recent research in the field of nanostructured ceramic materials has underscored the importance of using feedstock powders with metastable phases. During material consolidation the metastable structure evolves into a dual structure where the grain growth stops when the crystallites reach their respective equilibrium grain size. The mutual suppression of the grain growth is a direct consequence of the immiscibility of the two phases in the solid state. Due to their small grain size and uniform structure, the nanocomposites exhibiting very interesting properties, are formed. Metastable structures can be produced using atmospheric plasma spray (APS) technique. The main target of this work has been the synthesis of Al₂O₃-TiO₂ metastable powder through atmospheric plasma spraying (APS) and quenching route. The metastable phases have been produced from micron-sized feedstock powders and the effect of different raw powders have also been evaluated. The metastable phases have been characterised by XRD, SEM and FESEM analysis. The availability of producing nanostructured materials through these metastable phases have been studied. The phase and morphology evolution from this metastable phases to nanostructures has been observed.