1. Introduction 2. The physical metallurgy of nickel and its alloys 3. Single crystal superalloys for blade applications 4. Superalloys for turbine disc applications 5. Environmental degradation: the role of coatings 6. Summary and future trends.

The Superalloys: Fundamentals and Applications

TiO 2 photocatalysis is widely used in a variety of applications and products in the environmental and energy fields, including self-cleaning surfaces, air and water purification systems, sterilization, hydrogen evolution, and photoelectrochemical conversion. The development of new materials, however, is strongly required to provide enhanced performances with respect to the photocatalytic properties and to find new uses for TiO 2 photocatalysis. In this review, recent developments in the area of TiO 2 photocatalysis research, in terms of new materials from a structural design perspective, have been summarized. The dimensionality associated with the structure of a TiO 2 material can affect its properties and functions, including its photocatalytic performance, and also more specifically its surface area, adsorption, reflectance, adhesion, and carrier transportation properties. We provide a brief introduction to the current situation in TiO 2 photocatalysis, and describe structurally controlled TiO 2 photocatalysts which can be classified into zero-, one-, two-, and three-dimensional structures. Furthermore, novel applications of TiO 2 surfaces for the fabrication of wettability patterns and for printing are discussed.

TiO2 photocatalysis: Design and applications

About Supramolecular Assemblies of π-Conjugated Systems

Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Interpretation of europium(III) spectra

This paper summarizes the basic properties of ceramic materials for thermal barrier coatings. Ceramics, in contrast to metals, are often more resistant to oxidation, corrosion and wear, as well as being better thermal insulators. Except yttria stabilized zirconia, other materials such as lanthanum zirconate and rare earth oxides are also promising materials for thermal barrier coatings.

Ceramic materials for thermal barrier coatings

Zirconates with high melting points were investigated for
application as materials for thermal barrier coatings at operating temperatures >1300°C. SrZrO3, BaZrO3, and La2Zr2O7
powders were synthesized and sintered to compacts with
various levels of porosity. The sintering results indicated a promising low-sintering activity of the investigated materials. Thermal properties of these dense materials were determined. Thermal expansion coefficients were slightly lower than those of Y2O3-stabilized ZrO2 (YSZ); thermal conductivities of SrZrO3 and BaZrO3 were comparable or slightly higher than those of YSZ. La2Zr2O7 had a lower thermal conductivity. SrZrO3 was not suitable for application as a thermal barrier coating because of a phase transition at temperatures between 700° and 800°C. Mechanical properties (hardness, fracture toughness, and Young’s modulus) of dense BaZrO3 and La2Zr2O7 samples were determined by indentation techniques and showed lower hardness and Young’s modulus compared to YSZ. BaZrO3 and La2Zr2O7 powders were optimized for application as powders for plasma spraying. Plasma-sprayed coatings were produced and characterized. Thermal cycling with a gas burner at 1200°C showed a massive attack of the BaZrO3 coating, with loss of BaO. On the other hand, the La2Zr2O7 coating showed excellent thermal stability and thermalshock behavior.

Zirconates as New Materials for Thermal Barrier Coatings

Lanthanum–Cerium Oxide as a Thermal Barrier‐Coating Material for High‐Temperature Applications

A series of La 2 O 3 –ZrO 2 –CeO 2 composite oxides were synthesized by solid-state reaction The final product keeps fluorite structure when the molar ratio Ce/Zr ≥ 07/03, and below this ratio only mixtures of La 2 Zr 2 O 7 (pyrochlore) and La 2 O 3 –CeO 2 (fluorite) exist Averagely speaking, the increase of CeO 2 content gives rise to the increase of thermal expansion coefficient and the reduction of thermal conductivity, but La 2 (Zr 07 Ce 03 ) 2 O 7 has the lowest sintering ability and the lowest thermal conductivity which could be explained by the theory of phonon scattering Based on the large thermal expansion coefficient of La 2 Ce 325 O 95 , the low thermal conductivities and low sintering abilities of La 2 Zr 2 O 7 and La 2 (Zr 07 Ce 03 ) 2 O 7 , double-ceramic-layer thermal barrier coatings were prepared The thermal cycling tests indicate that such a design can largely improve the thermal cycling lives of the coatings Since no single material that has been studied so far satisfies all the requirements for high temperature thermal barrier coatings, double-ceramic-layer coating may be an important development direction of thermal barrier coatings

New double-ceramic-layer thermal barrier coatings based on zirconia–rare earth composite oxides

Molybdenum trioxide nanobelts and prism-like particles with good crystallinity and high surface areas have been prepared by a facile hydrothermal method, and the morphology could be controlled by using different inorganic salts, such as KNO3, Ca(NO3)2, La(NO3)3, etc The possible growth mechanism of molybdenum trioxide prism-like particles is discussed on the basis of the presence of H+ and the modification of metal cations The as-prepared nanomaterials are characterized by means of powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and ultraviolet and visible spectroscopy (UV−vis) TEM and HRTEM micrographs show that the molybdenum trioxide nanobelts and prism-like particles have a relatively high degree of crystallinity and uniformity BET specific surface areas of the as-prepared molybdenum trioxide nanocr

Xueqiang Cao

Papers

Ceramic materials for thermal barrier coatings

Zirconates as New Materials for Thermal Barrier Coatings

Lanthanum–Cerium Oxide as a Thermal Barrier‐Coating Material for High‐Temperature Applications

New double-ceramic-layer thermal barrier coatings based on zirconia–rare earth composite oxides

Morphology-controllable synthesis and characterization of single-crystal molybdenum trioxide.