Synthesis of Gd2Zr2O7 Coatings Using the Novel Reactive PS-PVD Process

Abstract

Ceramic topcoats of thermal barrier coatings (TBCs) make it possible to increase the working temperature of the hot sections of jet engines. Yttria-stabilized zirconia oxide (YSZ) is usually used to protect the turbine blades and vanes against high temperature and oxidation. It is necessary to develop new materials which can operate at higher temperatures in a highly oxidizing gas atmosphere. Re2Zr2O7-type pyrochlores are promising YSZ replacements. Usually, they are produced by mixing pure oxides in the calcination process at higher temperatures. In a recent article, the new concept of pyrochlore synthesis during the deposition process was presented. The new technology, called reactive plasma spray physical vapor deposition (reactive PS-PVD), was developed and a Gd2Zr2O7 (GZO) coating was achieved. The reactive PS-PVD process allowed for the use of a mixture of untreated ZrO2 and Gd2O3 powders as reactants, instead of the commercially available gadolinium zirconate powders used in other types of processes. The results of microstructure observations revealed a columnar microstructure in the produced ceramic layer. The phase composition indicated the presence of gadolinium zirconate. Thermal analysis showed a decrease in the thermal conductivity in the range of 700 to 1200 °C of the produced layers, as compared to the layer made of the currently used conventional YSZ.

The Influence of Reactive PS-PVD Process Parameters on the Microstructure and Thermal Properties of Yb2Zr2O7 Thermal Barrier Coating

“…They formed as a result of secondary crystallization of material observed when longer spray distance of PS-PVD processes was used [39]. The obtained results of microstructure analysis showed that structure of YZO coating are similar to previously synthetized gadolinium zirconate coating [32].…”

“…Both the bond-coat and ceramic topcoat were produced using the LPPS-Hybrid system (Oerlikon-Metco, Switzerland) in the Research and Development Laboratory for Aerospace Materials at Rzeszow University of Technology, Poland. The basic process parameters of the topcoat production were selected based on our previous research [32][33][34][35][36]. The experimental process parameters are presented in Table 1.…”

“…Comparative study of the properties of double-layer TBCs containing gadolinium zirconate and yttriastabilized zirconia (YSZ) with a single-layer Gd 2 Zr 2 O 7 coating was also performed [31]. In our previous research, we proposed a new Reactive PS-PVD method and the formation of well-investigated gadolinium zirconate during reaction of gadolinia and zirconia oxides in a plasma plume [32]. In present article, we synthetized Ytterbia Zirconate using a novel reactive PS-PVD process.…”

Investigation of the Relationship between Degradation of the Coating of Gas Turbine Blades and Its Surface Color

“…It has been found that the maximum content of total sulfur in fuels for turbine Additionally, it has been observed that the coating covering the blade's leading edge consists of two layers: an external layer responsible for thermal resistance having an aluminum content of approximately 29% and a thickness of about 40 µm and an inner layer responsible for transferring strain containing approximately 24% Al and having a thickness of about 50 µm. The increased content of aluminum within the zone that is expected to be exposed to the highest temperatures is supposed to facilitate the formation of protective aluminum or chromium oxide layers that are created during engine operation [41,42]. Al 2 O 3 and Cr 2 O 3 [43] form as a result of oxygen diffusion into the coating as well as the core diffusion of aluminum and chromium.…”

Design of newly developed burner rig operating with hydrogen rich fuel dedicated for materials testing

“…Typically for conventional fuel gas turbines the thermal barrier coatings are used for protection of Nickel-superalloys surface material (Grilli et al, 2021;Suzuki et al, 2022). The outer ceramic layer contains usually yttria stabilized zirconia oxide (YSZ) (Golewski and Sadowski, 2019) or pyrochlores (Pędrak et al, 2021;. The bond coat protects surface against oxidation and hot corrosion and might be formed from MCrAlYtype alloys (Zakeri et al, 2022) or by production of aluminide coatings (Góral et al, 2021;Kopec et al, 2021).…”