Nanostructured Pure and Doped Zirconia: Synthesis and Sintering for SOFC and Optical Applications

Zirconia is a multifunctional material with potential applications in wide domains. Rare-earth doped zirconia and stabilized zirconia yield interesting properties based on the phase transitions induced by the sintering conditions. Zirconia nanopowders were prepared by hydrothermal technique. Synthesis methods of zirconia with various rare earths are discussed here. An overview of the sintering of zirconia-based ceramics is presented in particular for SOFC and sensors and optical applications

The methodologies and strategies for the development of novel material systems and coatings for applications in extreme environments - a critical review

The aim of this paper is to present a critical analysis of existing methodologies, approaches and strategies used to develop materials systems and coatings for uses in extreme environments. The extreme or harsh conditions encompass a large variety of in-service forms such as: extreme temperatures, abrasion, corrosion, impact and radiation that can exist in various applications such as those associated with aerospace and aeronautical engineering, land and marine transport, manufacturing machinery, and even microelectronics products. This article describes how working environment and required service performance of a particular part or structure could affect the choice of materials and surfaces to which it is composed. In addition, the paper explains the relevance that abusive working environments have for industry, especially relating to their costs, being followed by an overview of surface deposition approaches that are currently popularly used to improve performance of mechanical devices that need to combat adverse conditions. Finally, a material system and three kinds of protective coatings that could be used in applications in extreme conditions are described. The critical review is an outcome of the strategic review from the EU H2020 SUPERMAT project which deals with materials and manufacture for the products/structural parts used in extreme conditions

Elaboration, caracterisation et modelisation de ceramiques magnetodielectriques a couches d'arret

INIST T 73686 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

High pressure synthesis in materials science

High pressure (HP) is an integral part of various domains of science. The combination of temperature with pressure results in applications in several already existing fields, such as steam sterilization by autoclave in medicine, single crystal of a-quartz SiO2 by hydrothermal crystal growth in inorganic chemistry, polymerization by reactor in organic chemistry, Pascalization of biologic materials by high hydrostatic vessel in organic chemistry or pharmacy. In inorganic materials chemistry, pressure allows, in addition to temperature, to sinter/consolidate/densify for obtaining solid material in the form generally as ceramic (sintering phenomena) or as monoliths (consolidation phenomena) with dense (by densification) or porous (by interparticle bridging) form. Innovative HP processes were designed for the high pressure syntheses related to: high pressure structural phase (e.g., diamonds instead of graphite) or low temperature structural phase (e.g., for SiO2: quartz instead of the other polymorphs, or amorphous instead of crystallized), consolidation of porous or dense biocomposites, sintering at temperature higher than their thermal decomposition, preservation of hydrates from the raw precursor, initiating a new finer microstructure, higher densification, improvement or driving the chemical reaction, assembling of materials with different thermal stability (e.g., multimaterials). Recently, innovative high pressure processes have emerged by the combination of different technologies opening new possibility for obtaining these advanced functional inorganic materials such as: high pressure & spark plasma sintering, cold isostatic pressure & minus temperature, hydrothermal synthesis & sintering.Michał Bembenek andAndrzej Uhryński, Analysis of the Temperature Distribution on the Surface of Saddle-Shaped Briquettes Consolidated in the Roller Press, Materials 2021, 14(7), 1770; https://doi.org/10.3390/ma14071770 - 03 Apr 2021érémy Guignard,Mythili Prakasam and Alain Largeteau, A Review of Binderless Polycrystalline Diamonds: Focus on the High-Pressure–High-Temperature Sintering Process, Materials 2022, 15(6), 2198; https://doi.org/10.3390/ma15062198 - 16 Mar 2022Yann Le Godec andAlexandre Courac, In Situ High-Pressure Synthesis of New Outstanding Light-Element Materials under Industrial P-T Range, Materials 2021, 14(15), 4245; https://doi.org/10.3390/ma14154245 - 29 Jul 2021Javier Gainza,Federico Serrano-Sánchez,João Elias F. S. Rodrigues,Norbert Marcel Nemes,José Luis Martínez and José Antonio Alonso, Metastable Materials Accessed under Moderate Pressure Conditions (P ≤ 3.5 GPa) in a Piston-Cylinder Press, Materials 2021, 14(8), 1946; https://doi.org/10.3390/ma14081946 - 13 Apr 202

Elaboration, caractérisation et modélisation de céramiques magnetodiélectriques à couches d'arrêt

Des céramiques ferrites à couches d'ârret de type spinelle et hautement densifiées ont été élaborées. Si les propriétés diélectriques varient fortement selon les conditions d' élaboration, les propriétés magnétiques sont au contraire peu altérées. Des relaxations diélectrique et d'impedance ont été mises en évidence, elles ont été modélisées; leurs caractéristiques ont été déterminées en fonction de la composition des grains et des paramètres de préparation des échantillons.non disponibl

Modern preservation tools through packaging for high hydrostatic pressure processing

High hydrostatic pressure (HHP) processing is a well-known method for processing by nonthermal means for various applications in food, pharmaceutical, and biological industries. The products are enveloped in a packaging material before subjecting to HHP. Extensive research has proved that HHP has no negative impact created when subjecting the food material to high pressure. Physical and chemical compatibility of the packaging material is mandatory to retain hermetical properties. Any negative influence of HHP on packaging material could cause adverse effects on the shelf life, quality, and safety of the food product. Essential properties of the packaging materials such as barrier and mechanical properties have to be investigated before usage. Influence on the packaging material by high pressure is vital for study of sterilization effect. Multilayers in the packaging material could lead to adhesion and a loss of structural integrity. In this chapter, various characteristics of the packaging materials required for HHP and their application in various domains utilizing packaging materials for HHP of biomaterials and their influence will be discussed in this chapter alongside the new developments in this domain

Terbium based crystals and transparent ceramics phosphors- fabrication and applications

The recent upsurge of investigations on luminescent properties of inorganic phosphors is due to the applications in flat panel displays and various other luminescent devices..

Thermoelectric and magneto-optic semiconductor single crystals and ceramics

Semiconductor materials have applications in vast fields and are the basis for modern electronics. Semiconductors materials have electrical conductivity intermediate between that of metal and insulators. In this chapter we will discuss about the applications of semiconductors in thermoelectric devices and magneto-optics..

Chimie solvothermale

Les réactions solvothermales peuvent être définies comme des réactions où des transformations de précurseurs se déroulent dans un système clos ou en flux continu, en présence d'un solvant au-delà de sa propre température d'ébullition (domaine (3) de la figure 1). Il en découle que selon la valeur de ce paramètre le solvant peut être soit à l'état subcritique, soit à l'état supercritique. La pression résultante peut être autogène, ou obtenue par compression à froid du solvant. Dans le domaine subcritique, la pression joue un rôle essentiel, la solubilité des réactifs pouvant être ajustée par modification de ce paramètre. Dans le cas de l'état supercritique, ce sont les propriétés physico-chimiques spécifiques du solvant qui jouent en permettant des mécanismes réactionnels particuliers..

Discussion on polycrystals over single crystals for optical devices

Conventional transparent materials have a strong absorption in the infrared region making them unsuitable in the spectral range. Crystal growth processes are usually very time‐consuming and needs sophisticated/expensive machines. Polycrystalline nature of the ceramics is prone to diffusing light, which primarily arises from residual pores, grain boundaries, secondary phases and birefringency (anisotropic materials). Rapid sintering techniques such as Spark Plasma Sintering (SPS) helps in obtaining maximum densification in short duration of time at comparatively lesser sintering temperatures in comparison to other classical sintering. With the recent technological advances in sintering technology and nanopowders fabrication, it is possible to obtain a dense ceramic that is transparent. Transparent ceramics processing with nanosized ceramic powders and advanced densification technology provides an alternative approach to overcome the disadvantages/limits of conventional single‐crystal growth process. Most of the current transparent ceramics are limited only to cubic materials, currently extended to non‐cubic materials as well though in early stages. Conventionally, either Hot‐Isostatic Pressing (HIP), or Hot Pressing (HP) or vacuum sintering at very high temperatures using ultrapure ultrafine powders often fabricates optically transparent ceramics. This paper demonstrates the fabrication of transparent ceramics of both cubic and non‐cubic crystal structured materials by Spark Plasma Sintering (SPS) for materials without any additives/sintering aids