Thermal barrier coatings (TBCs) can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat. However, the continuous pursuit of a higher operating temperature leads to degradation, delamination, and premature failure of the top coat. Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems. In this paper, the latest progress of some new ceramic materials is first reviewed. Then, a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth, ceramic sintering, erosion, and calcium-magnesium-aluminium-silicate (CMAS) molten salt corrosion. Finally, new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar, columnar, and nanostructure inclusions. The latest developments of ceramic top coat will be presented in terms of material selection, structural design, and failure mechanism, and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance, better thermal insulation, and longer lifetime.

Thermal transport properties of solid solution ${\left({\mathrm{La}}_x{\mathrm{Gd}}_{1-x}\right)}_2{\mathrm{Zr}}_2{\mathrm{O}}_7$ have been investigated for thermal barrier coatings (TBCs) application. The introduction of point defects was intended to provide extra phonon scattering, and much lower thermal conductivity for the solid solution has been obtained compared with ${\mathrm{La}}_2{\mathrm{Zr}}_2{\mathrm{O}}_7$ and ${\mathrm{Gd}}_2{\mathrm{Zr}}_2{\mathrm{O}}_7$. The phonon mean free paths of the solid solution were estimated and discussed with respect to the point defect scattering effect. Young’s modulus and heat capacity of the solid solution, which determine the mean velocity and the carried energy of the phonons, respectively, were measured and both showed suppression compared with the end materials, possibly due to the lattice relaxation aroused by point defects. A theoretical model, which contains no adjustable parameters, was present to accurately describe the thermal conductivities of the solid solution by taking account of the mass and strain field fluctuations induced by the point defects.

This paper provides a brief review of current research activities that focus on the synthesis and controlled assembly of inorganic nanofibers by electrospinning, their electrical, optical and magnetic properties, as well as their applications in various areas including sensors, catalysts, batteries, filters and separators. We begin with a brief introduction to electrospinning technology and a brief method to produce ceramic nanofibers from electrospinning. We then discuss approaches to the controlled assembly and patterning of electrospun ceramic nanofibers. We continue with a highlight of some recent applications enabled by electrospun ceramic nanofibers, with a focus on the physical properties of functional ceramic nanofibers as well as their applications in energy and environmental technologies. In the end, we conclude this review with some perspectives on the future directions and implications for this new class of functional nanomaterials. It is expected that this review paper can help the readers quickly become acquainted with the basic principles and particularly the experimental procedure for preparing and assembly of 1D ceramic nanofiber and its arrays.

Dislocations are commonly present and important in metals but their effects have not been fully recognized in oxide ceramics. The large strain energy raised by the rigid ionic/covalent bonding in oxide ceramics leads to dislocations with low density (∼10⁶ mm⁻²), thermodynamic instability and spatial inhomogeneity. In this paper, we report ultrahigh density (∼10⁹ mm⁻²) of edge dislocations that are uniformly distributed in oxide ceramics with large compositional complexity. We demonstrate the dislocations are progressively and thermodynamically stabilized with increasing complexity of the composition, in which the entropy gain can compensate the strain energy of dislocations. We also find cracks are deflected and bridged with ∼70% enhancement of fracture toughness in the pyrochlore ceramics with multiple valence cations, due to the interaction with enlarged strain field around the immobile dislocations. This research provides a controllable approach to establish ultra-dense dislocations in oxide ceramics, which may open up another dimension to tune their properties.