Influence of embedded MoSi2 particles on the high temperature thermal conductivity of SPS produced yttria-stabilised zirconia model thermal barrier coatings

Abstract

Influence of embedded MoSi 2 particles on the high temperature thermal conductivity of SPS produced yttria-stabilised zirconia model thermal barrier coatings, Surface & Coatings Technology (2016), doi:10.1016/j.surfcoat.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D Abstract:To prolong the lifetime of thermal barrier coatings (TBCs) recently a new method of microcrack healing has been developed, which relies on damage initiated thermal decomposition of embedded molybdenum disilicide (MoSi 2 ) particles within the TBC matrix.While these MoSi 2 particles have a beneficial effect on the structural stability of the TBC, the high thermal conductivity of MoSi 2 may have an unfavourable but as yet unquantified impact on the thermal conductivity of the TBCs.In this work the thermal conductivity of spark plasma sintering (SPS) produced yttria-

Modelling the fracture behaviour of thermal barrier coatings containing healing particles

“…In [22], crack propagation studies were conducted in an idealised healing capsule(s)-matrix system and the effects of geometric and material parameters were analysed using cohesive and extended finite element method (XFEM). Within the context of self-healing TBC systems, few modelling studies have addressed the effect of the healing particles on the TBC properties and the thermomechanical response [29,30]. The effect of the healing particles on the fracture mechanisms and the mechanical properties of a particulate composite representing a self-healing TBC microstructure were studied using cohesive element-based finite element analysis in [31][32][33].…”

Damage evolution in a self‐healing air plasma sprayed thermal barrier coating containing self‐shielding MoSi2 particles

“…Rather than manufacture a topcoat with MoSi 2 particles distributed homogenously throughout the entire coating, the MoSi 2 particles were deposited exclusively in the regions close to the interface where cracking and delamination predominately occur. This design not only maximised the probability for the particles to intersect with the propagating cracks and involve in subsequent crack healing, but also minimised the effect of healing particles on the overall properties (eg coefficient of thermal expansion (CTE), thermal conductivity and stiffness) of the topcoat . The volume fraction of the MoSi 2 particles embedded in the YSZ topcoat near the interface is about 10 vol.%.…”

A micromechanical fracture analysis to investigate the effect of healing particles on the overall mechanical response of a self‐healing particulate composite

“…Additional information of the composite material such as manufacturing process and details of the material constituents of the composite can be found elsewhere. 34 The geometry of the microstructure shown in Figure 1 was generated through postprocessing of an SEM image of the composite cross-section, which is then translated into a finite element mesh; see right side of Figure 1 showing a part of the mesh. A small initial precrack of length equal to 0.025 mm was included on the left side of the composite specimen.…”

“…Correspondingly, the objective of the present research is to study the crack propagation in a real microstructure of a self‐healing particulate composite, followed by the quantification of the effect of the healing particles and their properties on the composite mechanical behaviour. This is achieved through numerical analysis using a finite element model generated directly from an actual microstructure of the MoSi 2 ‐YSZ composite . The motivation is to reveal the roles of these parameters to experimental researchers, which could be helpful in the design and development of self‐healing systems with least compromised mechanical property values of the original intact base material.…”

“…This is achieved through numerical analysis using a finite element model generated directly from an actual microstructure of the MoSi 2 -YSZ composite. 34 The motivation is to reveal the roles of these parameters to experimental researchers, which could be helpful in the design and development of self-healing systems with least compromised mechanical property values of the original intact base material.…”