Recently, application of ceramic coatings to space vehicles to generate thermal barriers upon re-entry is being considered as a challenge for research. Conventionally, thermal barrier coatings (TBC) are utilized to increase the gas turbine engine components' thermal and oxidation resistance values in order to get higher power and efficiency values. In this study, various superalloys and stainless steels were thermal barrier coated using the atmospheric plasma spraying method. One goal is to determine the effect of the substrate on the performance of the coating. Coating morphology was determined using microscopy analysis. Various heat exposure procedures were applied to the specimens and the changes in the mechanical properties of the top coat were analyzed using indentation techniques. Durability of the coatings after various periods at 1100 degrees C was examined. Microstructures, coatings and reaction products were characterized by optical microscopy and image analysis. Effects of TBC thickness variations were also analyzed in order to achieve a model for determining the optimum coating thickness.