The thermomechanical properties of thermal barrier coatings (TBCs) such as elastic modulus, thermal conductivity, and coefficient of thermal expansions are determined by pores, cracks, and splat boundaries, which affect the thermoelastic properties of thermally grown oxide (TGO) layer and the fracture behavior in TBCs. The thermoelastic characteristics thus have been investigated through mathem...

To understand the oxidation behaviors of NiCrAlY bond coats in thermal barrier coatings (TBCs) under external loads, uniaxial tensile and compressive experiments TBCs air at 900 °C for 100 h were investigated. Then, experimental results explained by first-principles simulation. The showed that rate coat was accelerated stresses. A 0.9 μm thickness, a thermally grown oxide (TGO) layer found with...

A thermal barrier system with plasma-sprayed thermal barrier coating (TBC) has been analyzed subject to thermal cycling. The thermally grown oxide (TGO) is allowed to grow at the peak temperature in the cycle, with both thickening and lateral components of the growth strain. The stresses in the TGO are also allowed to relax at high temperature when they attain a critical level. The bond coat is...

An air plasma spray process has been used to apply a model tri-layer Yb2SiO5/Al6Si2O13/Si environmental barrier coating system on SiC test coupons. Significant differences in the thermal expansion of the component layers resulted in periodically spaced mud cracks in the Yb2SiO5 and Al6Si2O13 layers. Upon thermal cycling between 1316°C and 110°C in a 90% H2O/10% O2 environment flowing at 4.4 cm/...

A new multi-layered thermal barrier coating system (TBCs) containing gadolinium zirconate (GZ, Gd2Zr2O7) and yttria-stabilized zirconia (YSZ) was developed using suspension plasma spray (SPS) to improve the overall cycling performance. This study focuses on cracking behavior of GZ/YSZ TBC after exposure find out key factors that limit its lifetime. Different behaviors were detected depending tr...

Thermal barrier coating systems are used on top of highly stressed components in gas turbines to protect the nickel-based substrates. A well-established thermal barrier coating system consist of the bond-coat (BC) and the thermal barrier coating (TBC). A third layer is grown during service: the thermally grown oxide (TGO) between the BC and the TBC. The coatings fail in service because of diffe...

Considering the influence of non-equibiaxial stress state and initial residual strain on compressive buckling ceramic layer, a quantitative characterization method damage generated at interface between top coat bond in thermal barrier coating based uniaxial compression was developed. It verified by axial tests single crystal specimens with EB-PVD after undergoing various isothermal oxidation ti...

The performance of an SOFC stack is related to the evolution over time materials during operation. Metallic interconnects (MICs) are exposed high temperature (ca. 850 °C) and dual atmosphere (fuel air streams), hence react form oxide scale on top. This paper focuses fuel side MIC investigates nature oxides formed in stacks field operated by SUNFIRE GmbH Company for up 20,000 h frame EU-H2020 AD...

Coatings subject to residual compression eventually fail by buckle-driven delamination. The phenomenon is most vivid in thermal barrier coatings (TBCs) used in gas turbines. The failure evolution commences with the formation of a large number of small cracks at geometric imperfections near the interface. These cracks spread upon thermal exposure, particularly upon thermal cycling, because of th...

Article history: Received 18 March 2016 Revised 16 July 2016 Accepted in revised form 28 July 2016 Available online xxxx Photoluminescence piezospectroscopy (PLPS) was used as a non-destructive technique for the measurement of residual stresses within the thermally grown oxide (TGO) layer beneath plasma-spray thermal barrier coatings (TBC). The technique has proved to be very effective for such...