Diffusion barrier coatings with active bonding, designed for gas turbine blades

Cyclic oxidation and diffusion barrier behaviors of oxides dispersed NiCoCrAlY coatings

“…The migration of elements across the interface alters the chemical compositions and microstructures of both the bond coat and the underlying superalloy substrate in the vicinity of the interface [8][9][10]. For instance, inward diffusion of Al and Cr from the bond coat could degrade the oxidation resistance of the coating [11,12].…”

Improvement of oxidation-resistance of NiCrAlY coatings by application of CrN or CrON interlayer

“…However, the adhesive strength of the NiCrAlY/ CrON coating system was still disputed. 6 and 10), not three-layer structure, 25 decreased the probability of interlayer delamination. This can be attributed to the following reasons.…”

“…13,25 However, the preliminary results from the debonding tests and modified four-point bending tests show that the presence of interlayer did not reduce the adhesive strength of NiCrAlY coatings on DSM11 substrate markedly. However, the adhesive strength of the NiCrAlY/ CrON coating system was still disputed.…”

Microstructural characteristics and degradation mechanism of the NiCrAlY/CrN/DSM11 system during thermal exposure at 1100 °C

“…During long-term service at high temperature atmosphere, the protection effect of MCrAlY coatings is impaired by elemental interdiffusion between the coatings and the substrate [4][5][6]. It is described that the interdiffusion accelerates the protective surface scales spalling and makes the continuous scales not regenerated because of the depletion of Cr and Al elements.…”

“…With the introduction of diffusion barrier into the coating/substrate interface, two major questions are raised that whether the interfacial bonding strength of the coating system is markedly weakened and the oxidation-resistance of the coatings can be improved [5,7]. With the aid of tensile adhesion test, it is found that the interfacial adhesion is about 70 MPa in the annealed MCrAlY/CrN/DSM11 system (herein CrN is as a diffusion barrier), better than that with CrON diffusion barriers.…”