Influence of TiO2 Alloying Percentage on the Morphology of APS-deposited Coatings from Cr2O3 Powders

In this paper we studied how alloying with different percentages of TiO2 influences the microstructure of Cr2O3 base matrix coatings deposited by plasma spray (APS). Thus, five different types of coatings were made, in which the percentage of TiO2 varied as 0%, 10%, 20%, 30% and 40%. The samples were analysed morphologically both on the surface and in cross-section using direct observation and electron microscopy (SEM). It was observed that none of the TiO2-containing coatings is a simple blend of distinct phases, but are coatings with a specific layered lamellar structure, with coarser and smooth areas, depending on the Ti wt.% presence. All the coatings analysed show micro cracks, porosities and inhomogeneous structure, but with a higher density directly proportional to the percentage of TiO2 in the composition of the coated powder.