Because of the attention to microstructural design and processing control, advanced ceramics often are high value-added products.
- Embryos, Genes and Birth Defects?
- An Afterclap of Fate: Mallory on Everest.
- eBusiness and Workplace Redesign!
- Greek Sculpture: The Late Classical Period and Sculpture in Colonies and Overseas!
- Ultrasound in Emergency Care.
- About the author.
- Advanced ceramics!
Advanced ceramics are referred to in various parts of the world as technical ceramics, high-tech ceramics, and high-performance ceramics. The terms engineering ceramics and fine ceramics are used in the United Kingdom and Japan, respectively. In this article the term advanced ceramics is used in order to distinguish the material from traditional ceramics, a category of industrial ceramics based on raw materials that are fabricated into products with comparatively little alteration from their natural state.
Ceramic Materials Processes, Properties and Applications | Engineering
The manufacture of traditional ceramics is covered in the article traditional ceramics. This article focuses on the types of chemical precursors and processing techniques employed in the manufacture of all advanced ceramic products. Like their traditional counterparts, advanced ceramics are often made by mixing and calcining firing together precursor powders. Unlike traditional ceramics, however, naturally occurring raw materials are seldom employed.
Instead, highly pure synthetic precursors are typically used. In addition, liquid-phase sintering, a method of densifying powders that is common in traditional ceramic processing, is seldom employed. Instead, advanced ceramics are densified by transient-liquid sintering also referred to as reactive-liquid sintering or solid-state sintering described later in this article. The most important factor in these sintering methods is small particle size.
Small particles have a larger ratio of surface area to mass and therefore yield a higher driving force for sintering. Small particle sizes also reduce the distances over which diffusion of material must take place. Ceramists therefore take care to produce active ceramic powders with small grain size, usually in the submicrometre range—i.
- Deadly Relations: Bester Ascendant (Babylon 5)?
- Ceramics - Materials, Joining and Applications - TWI!
- Ceramics Materials: Processes, Properties and Applications;
- Recent Translational Research in HIV AIDS.
- Land Reclamation: Extending the Boundaries : Proceedings of the Seventh International Conference of the International Affiliation of Land Reclamationists, Runcorn, United Kingdom, 13-16 May 2003!
- Im With Stupid (Felton Reinstein Trilogy, Book 3).
- Boundary Value Problems of Mathematical Physics and Related Aspects of Function Theory.
A major issue in the preparation of powdered precursors, especially for electroceramic applications, is chemical homogeneity —that is, the establishment of uniform chemical composition throughout the mixture. Standard solid-state techniques for processing separate precursor powders can approach homogeneity in the final product only after many grinding and firing steps.
A number of chemical approaches therefore have been developed in order to improve mixing, even down to the atomic level.
Often these techniques involve the decomposition of salts—for instance, carbonates, nitrates, and sulfates—into the desired chemical form. Most ceramics, as is explained in the article ceramic composition and properties , are oxides of metallic elements, although many ceramics especially advanced ceramics consist of carbide, nitride, and boride compounds as well.
The various chemical techniques for achieving homogenous, small-grained powders are described in turn below. Often the salt compounds of two desired precursors can be dissolved in aqueous solutions and subsequently precipitated from solution by pH adjustment.
- The Elements of Non-Euclidean Geometry.
- Applications | Cerame-Unie - The European Ceramic Industry Association;
- HCI and User-Experience Design: Fast-Forward to the Past, Present, and Future.
- Shades of Grace.
- Timber Production and Biodiversity Conservation in Tropical Rain Forests.
- Ceramic Materials Processes, Properties and Applications;
This process is referred to as coprecipitation. With care, the resulting powders are intimate and reactive mixtures of the desired salts.
Technical Ceramics from The Ceramic Experts
In freeze-drying, another route to homogenous and reactive precursor powders, a mixture of water-soluble salts usually sulfates is dissolved in water. This book is primarily an introduction to the vast family of ceramic materials. The first part is devoted to the basics of ceramics and processes: raw materials, powders synthesis, shaping and sintering.
The second part focuses on properties and applications, and discusses both structural and functional ceramics, including bioceramics. The fields of abrasion, cutting and tribology illustrate the importance of mechanical properties. As chemistry is an essential discipline for ceramicists, the book shows, in particular, what soft chemistry can contribute as a result of sol-gel methods.
Related Ceramic Materials: Processes, Properties and Applications
Copyright 2019 - All Right Reserved