The Technology of TBC Deposition by EB-PVD Method

Abstract

The role of thermal barrier coatings is to ensure heat resistance of elements in the hot section of turbofan aircraft engines in high temperatures. Stages of the production process are made up of preparing the base material, forming the aluminide interlayer by chemical vapour deposition method and depositing of the ceramic coating. The paper presents results of tests into microstructure of ZrO2 and Y2O3 ceramic coatings formed by EB-PVD method. The microstructure was assessed in several spots of the turbine blade of a high pressure turbofan engine by means of determining the coating thickness as well as height and width of ceramic columns, depending on the forming conditions.

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

“…The main achievement that we presented in this paper was the synthesis of pyrochlores using the newly developed reactive PS-PVD process, using only a mixture of ZrO2 and Gd2O3 powders, as well as the production of layers with a columnar structure similar to those produced in the EB-PVD process [35]. The layer made of gadolinium zirconate (GZO) in the 1800, 2000, and 2200 A processes had similar values of thermal diffusivity and thermal conductivity in the temperature range 700-1200 °C, and had thermal diffusivity and thermal conductivity values about 40% lower than those of YSZ [38,39].…”

“…The ceramic layers had thicknesses of, respectively, 118 +/− 27 µm (GZO-1800A), 125 +/− 7 µm (GZO-2000A) and 127 +/− 5 µm (GZO-2200A). The columns grew perpendicularly to the surface of the substrate, like the ceramic strips made by the gadolinium zirconate coating achieved in the conventional PS-PVD process by Li et al [28], and were very similar in shape to the columns obtained in the EB-PVD process [35]. The columns in the deposited ceramic layer were characterized by the presence of additional branches and a large number of open and closed pores between the growing columns and the branches [36].…”

The Microstructure of Hafnium Modified Aluminide Coatings Deposited by CVD Method

“…The behavior of the surface layer under corrosive gas, and mainly adhesion of the oxide layer formed during oxidation determines acceptable service life of the blades operating under gas corrosion conditions. The Thermal Barrier Coatings and aluminide coatings were developed for oxidation and corrosion protection of turbine blades as well [2][3][4][5][6][7][8]. In order to improve properties of the aluminide coatings in resistance to gas corrosion of industrially produced protective coatings on the blades of the turbojet engine there are used aluminide coatings modified with Pt, Hf, Y and Zr [9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”