title: Effect of La2O3 addition on interface chemistry between 4YSZ top layer and Ni based alloy bond coat in thermal barrier coating by EB PVD.
abstract: The effect of a 5 mol% La2O3 addition on the forming behavior and compositional variation at interface between a 4 mol% Yttria (Y2O3) stabilized ZrO2 (4YSZ) top coat and bond coat (NiCrAlY) as a thermal barrier coating (TBC) has been investigated. Top coats were deposited by electron beam physical vapor deposition (EB PVD) onto a super alloy (Ni-Cr-Co-Al) substrate without pre-oxidation of the bond coat. Top coats are found to consist of dense columnar grains with a thin interdiffusion layer between metallic bond coats. In the as-received 4YSZ coating, a thin interdiffusion zone at the interface between the top and bond coats was found to consist of a Ni-Zr intermetallic compound with a reduced quantity of Y, Al or O elements. On the other hand, in the case of an interdiffusion area of 5 mol% La2O3-added 4YSZ coating, it was found that the complicated composition and structure with La-added YSZ and Ni-Al rich compounds separately. The thermal conductivity of 5 mol% La2O3-added 4YSZ coating (- 1.6 W/m x k at 1100 degrees C) was lower than a 4YSZ coating (- 3.2 W/m x k at 1100 degrees C) alone.
authors.forename: Chan-Young
authors.initials: CY
authors.lastname: Park
authors.forename: Young-Hwan
authors.initials: YH
authors.lastname: Yang
authors.forename: Seong-Won
authors.initials: SW
authors.lastname: Kim
authors.forename: Sung-Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Hyung-Tae
authors.initials: HT
authors.lastname: Kim
authors.forename: Byung-Koog
authors.initials: BK
authors.lastname: Jang
authors.forename: Dae-Soon
authors.initials: DS
authors.lastname: Lim
authors.forename: Yoon-Suk
authors.initials: YS
authors.lastname: Oh