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Topic Review
CAD/CAM Ceramics
CAD/CAM ceramics present a promising alternative to metal-ceramic fixed dental prostheses.
  • 936
  • 23 Jun 2021
Topic Review
LaGaO3-Based Solid Oxide Fuel Cell Electrolytes
Solid oxide fuel cells (SOFCs) are efficient electrochemical devices that allow for the direct conversion of fuels (their chemical energy) into electricity. Although conventional SOFCs based on YSZ electrolytes are widely used from laboratory to commercial scales, the development of alternative ion-conducting electrolytes is of great importance for improving SOFC performance at reduced operation temperatures. The basic information has been studied on representative family of oxygen-conducting electrolytes, such as doped lanthanum gallates (LaGaO3). Complex oxides based on LaGaO3 offer a convenient basis for the design of oxygen-conducting electrolytes that can be employed in intermediate-temperature solid oxide fuel cells. A rational combination of appropriate dopants incorporated at various sublattices of LaGaO3 allows superior transport properties to be achieved for co-doped derivatives (La1−xSrxGa1−yMgyO3−δ, LSGM).
  • 929
  • 20 Jun 2022
Topic Review
Application of Geopolymers in Adsorption
Geopolymer is a porous inorganic material with a three-dimensional mesh structure, good mechanical properties, a simple preparation process (no sintering) and a low economic cost, and it is environmentally friendly. Geopolymer concrete has been widely used in the construction field, and many other studies have revealed that geopolymer will become one of the most promising inorganic materials with unique structure and properties. Geopolymer has a three-dimensional mesh structure that provides the geopolymer with high porosity and a significant number of mesopores that enhance the adsorption capacity by providing more exposed binding sites on the surface. The high mesoporous structure, high porosity, and three-dimensional mesh structure give geopolymers a larger specific surface area, which increases the contact sites with pollutants and impurities. 
  • 926
  • 14 Sep 2022
Topic Review
Approaches to Preceramic Polymer Fiber Fabrication
The demand for lightweight, high-modulus, and temperature-resistant materials for aerospace and other high-temperature applications has contributed to the development of ceramic fibers that exhibit most of the favorable properties of monolithic ceramics. The preceramic polymer requirements for a fiber concoction include: (1) appropriate rheology for non-Newtonian flows of materials and appropriate viscosity during rotation; (2) reactivity to fuse the fibers for subsequent pyrolysis; (3) controlled degradation during pyrolysis to prevent disorders of the structure, such as scattered material, and to produce high-density fibers with high ceramic performance; (4) controlled formation of nano- or microstructures.
  • 919
  • 15 Jul 2022
Topic Review
Hybrid Graphene/Fiber Reinforced Cementitious Composites
Graphene with fascinating properties has been deemed as an excellent reinforcement for cementitious composites, enabling construction materials to be smarter, stronger, and more durable. However, some challenges such as dispersion issues and high costs, hinder the direct incorporation of graphene-based reinforcement fillers into cementitious composites for industrial production. The combination of graphene with conventional fibers to reinforce cement hence appears as a more promising pathway especially towards the commercialization of graphene for cementitious materials.  This entry introduces the preparation and the enhancement of hybrid graphene-fiber reinforced cementitious composites.
  • 890
  • 09 Oct 2021
Topic Review
Thin-Film Fabrication for Low-Temperature Solid Oxide Fuel Cells
Solid oxide fuel cells (SOFCs) are amongst the most widely used renewable alternative energy systems with near-zero carbon emission, high efficiency, and environment-friendly features. However, the high operating temperature of SOFCs is still considered a major challenge due to several issues regarding the materials’ corrosion, unwanted reactions between layers, etc. Thus, low-temperature SOFCs (LT-SOFCs) have gained significant interest during the past decades. Despite the numerous advantages of LT-SOFCs, material selection for each layer is of great importance as the common materials have not shown a desirable performance so far. In addition to the selection of the materials, fabrication techniques have a great influence on the properties of the SOFCs. As SOFCs with thinner layers showed lower polarisation resistance, especially in the electrolyte layer, different thin-film fabrication methods have been employed, and their effect on the overall performance of SOFCs has been evaluated.
  • 858
  • 23 Aug 2023
Topic Review
Oxidation Protection of High-Temperature Oxidation-Resistant Coatings
Molybdenum and its alloys, with high melting points, excellent corrosion resistance and high temperature creep resistance, are a vital high-temperature structural material. However, the poor oxidation resistance at high temperatures is a major barrier to their application. 
  • 843
  • 28 Feb 2022
Topic Review
Critical Minerals
Critical minerals are paramount to the successful deployment of low-carbon technologies in future transportation, defense, agriculture, healthcare, and infrastructure. They have a significant economic importance and their insecure supplies may hinder the development and industrial application of new technologies. An implementation of large quantities of minerals, in particular metals, into the clean energy transition will create new economic opportunities but also bring new challenges to energy security that could lead to unexpected dependencies on raw materials.
  • 839
  • 30 Aug 2022
Topic Review
Geopolymers vs. Cement Matrix Materials
Geopolymers are spreading more and more in the cementitious materials field, exhibiting technological properties that are highly competitive to conventional Portland concrete mixes.
  • 816
  • 24 Aug 2021
Topic Review
Deposition Parameters on the Microstructure of Multilayer Films
Multilayer films with high-density layer interfaces have been studied widely because of the unique mechanical and functional properties. Magnetron sputtering is widely chosen to fabricate multilayer films because of the convenience in controlling the microstructure. 
  • 787
  • 28 Dec 2021
Topic Review
Ceramic Nanostructured Coatings
Ceramic nanocoatings are widely used in many applications such as engine valves, boiler parts, automotive body parts, orthopaedic implants, etc., due to their excellent resistance to corrosion, oxidation and wear, as compared to metals, especially in high-temperature applications. They also have excellent thermal and electrical insulation properties.
  • 787
  • 29 Apr 2022
Topic Review
Research Progress on Preparation Methods of Skutterudites
Thermoelectric material is a new energy material that can realize direct conversion of thermal energy and electric energy. It has important and wide applications in the fields of the recycling of industrial waste heat and automobile exhaust, efficient refrigeration of the next generation of integrated circuits and full spectrum solar power generation. Skutterudites thermoelectric material has attracted much attention because of their excellent electrical transport performance in the medium temperature region. In order to obtain skutterudites thermoelectric materials with excellent properties, it is indispensable to choose an appropriate preparation method.
  • 741
  • 28 Sep 2022
Topic Review
Polymer-Derived Ceramics Technology
Ceramics have become indispensable materials for a wide range of industrial applications due to their excellent properties.
  • 704
  • 01 Dec 2022
Topic Review
Effect of Grain Size on B4C and β-SiC
Nanocrystalline materials are categorized as having average grain sizes below 100 nm with a larger volume fraction of grain boundaries (GBs), leading to significant changes in their mechanical, physical, and chemical properties. Lightweight polycrystalline ceramics possess promising physical, chemical, and mechanical properties, which can be used in a variety of important structural applications. However, these ceramics with coarse-grained structures are brittle and have low fracture toughness due to their rigid covalent bonding (more often consisting of high-angle grain boundaries) that can cause catastrophic failures. Owing to these failure mechanisms in polycrystalline ceramics, a reduction in grain size to a nano-regime, which is expected to enhance the combination of hardness (or strength), toughness, and ductility, provides a promising nanomechanical research direction compared to counterpart micro-sized polycrystalline ceramics. Apart from the effects of grain size itself, the mechanical properties of B4C and SiC also show high dependency on their properties such as composition variation, anisotropy, density, etc.
  • 701
  • 28 Sep 2022
Topic Review
Biomass Fly Ash-Based Geopolymers
The production of conventional cement involves high energy consumption and the release of substantial amounts of carbon dioxide (CO2), exacerbating climate change. Additionally, the extraction of raw materials, such as limestone and clay, leads to habitat destruction and biodiversity loss. Geopolymer technology offers a promising alternative to conventional cement by utilizing industrial byproducts and significantly reducing carbon emissions.
  • 678
  • 10 Aug 2023
Topic Review
LaAlO3-Based Solid Oxide Fuel Cell Electrolytes
Solid oxide fuel cells (SOFCs) are efficient electrochemical devices that allow for the direct conversion of fuels (their chemical energy) into electricity. Although conventional SOFCs based on yttria-stabilized zirconia (YSZ) electrolytes are widely used from laboratory to commercial scales, the development of alternative ion-conducting electrolytes is of great importance for improving SOFC performance at reduced operation temperatures. The basic information has been researched (synthesis, structure, morphology, functional properties, applications in SOFCs) on representative family of oxygen-conducting electrolytes, such as doped lanthanum aluminates (LaAlO3).
  • 630
  • 16 Jun 2022
Topic Review
Metal Oxide Semiconductor Gas Sensors with Different Morphologies
There is an increasing need for the development of low-cost and highly sensitive gas sensors for environmental, commercial, and industrial applications in various areas, such as hazardous gas monitoring, safety, and emission control in combustion processes. Considering this, resistive-based gas sensors using metal oxide semiconductors (MOSs) have gained special attention owing to their high sensing performance, high stability, and low cost of synthesis and fabrication. The relatively low final costs of these gas sensors allow their commercialization; consequently, they are widely used and available at low prices. Different morphologies of metal oxide gas sensors are discussed.
  • 604
  • 04 May 2023
Topic Review
Sodiophilicity Regulation in Metallic Na Anodes
The Na metal anode is the essential component for room-temperature sodium-metal batteries (SMBs), such as Na-S, Na-Se, and Na-O2. However, the practical application of liquid-electrolyte-based SMBs has been troubled by extensive volume change and mossy/dendritic growth during Na electrodeposition. In this regard, the sodiophilicity (of the solid electrolytes or 2D/3D Na hosts) has been widely deemed vital for achieving stable Na metal anodes in either solid- or liquid-electrolyte-based SMBs, and many strategies have emerged to improve Na wettability and stabilize Na metal anodes for the three types of batteries.
  • 600
  • 11 Jul 2022
Topic Review
Overview of the Development of ZnO-Based Varistors
Voltage surge protection devices (SPDs) or surge arresters rely on metal oxide varistors (MOVs) to safeguard electrical equipment in consumer electronics and industrial electric power systems against the destructive temporary overvoltages (TOVs) resulting from transient switching surges or lightning strikes. The primary function of voltage-sensitive MOVs in SPDs is to prevent the damage caused by high-energy transients by clamping or eliminating them when a surge occurs. These MOVs are mounted in parallel with the components that they are designed to protect.
  • 593
  • 29 May 2023
Topic Review
Gelatin and Bioactive Glass Composites
Nano-/micron-sized bioactive glass (BG) particles are attractive candidates for both soft and hard tissue engineering. They can chemically bond to the host tissues, enhance new tissue formation, activate cell proliferation, stimulate the genetic expression of proteins, and trigger unique anti-bacterial, anti-inflammatory, and anti-cancer functionalities. Composites based on biopolymers and BG particles have been developed with various state-of-the-art techniques for tissue engineering. Gelatin, a semi-synthetic biopolymer, has attracted the attention of researchers because it is derived from the most abundant protein in the body, viz., collagen. It is a polymer that can be dissolved in water and processed to acquire different configurations, such as hydrogels, fibers, films, and scaffolds.
  • 568
  • 28 Jan 2023
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