Abstract
The main purposes of applying the coatings on the surface of different components include the improvement of their functional and decorative properties. The functional properties of coating are strongly dependent on its microstructure. The main goal of the paper is to show the differences of two microstructures that can be obtained using suspension plasma spraying technology: (i) columnar one; and, (ii) lamellar, two-zone microstructure. Initially, the optimization of spray parameters was made and then the microstructural studies were performed. The work was focused on zirconia stabilized by yttria (YSZ) and both by yttria and ceria (YCSZ) which are most frequently used as thermal barrier coatings (TBC). Moreover, two types of microstructure were achieved using two different plasma torches, namely SG-100 of Praxair and Triplex of Sulzer Metco. After optimizing the spray parameters the microstructure of prepared coatings was analyzed using electron microscopy (SEM). The conventional SEM microscopy with secondary electrons detector (SE) and back scattered electrons one (BSE) were used. The energy dispersive spectroscopy (EDS) was performed to analyze the chemical composition. Finally, by electron backscatter diffraction (EBSD) grain shape, size and texture were determined for discussion of the coatings growth mechanism.
