Advanced Materials: TechConnect Briefs 2015Advanced Materials TechConnect Briefs 2015

Advanced Materials for Engineering Applications Chapter 7

Multi-layer Thermal Barrier Coating of a New Architecture

A.S. Kuzanyan, A.G. Petrosyan, A.A. Kuzanyan, S.I. Petrosyan, V. Stathopoulos
Institute for Physical Research, National Academy of Sciences, Armenia

pp. 460 - 461

Keywords: TBC, bondcoat, topcoat, multi-layer

Thermal barrier coating (TBC) provide a thermal and corrosion insulation layer able to decrease thermal loads on the surface of major operating metallic parts of gas turbines. Advanced thermal barrier coating systems have the following layered structure. The substrate made of refractory alloy is coated with an intermetallic bonding layer, referred as «bondcoat». On top of it a covering layer of refractory ceramic oxide is deposited named «topcoat». The bondcoat is usually made of MCrAlY, while the topcoat is stabilized zirconia. The search for means to increase the operation temperature of turbines (necessary to increase their efficiency) is directed to creation of new materials for TBC, as well as new structures of TBC, e.g., multi-layered TBC systems. The concept of the proposed technology is multi-layer TBC consisting of two-layer bondcoat and overlying topcoat oxide layer with an intermetallic first bonding layer. The second layer of the bonding layer is made of an oxide and has the chemical composition similar to that of the adjacent overlying topcoat oxide layer. The electron beam deposition method is used for the fabrication of oxide layer of bondcoat, while the overlying oxide topcoat layer is obtained by atmosphere plasma spraying method.