Alumina Fibers applications

The properties of alumina listed in Sects. 4-10 show the unusual performance of pure alumina, leading to the variety of applications given in Table 1. Practical aluminas with impurities and defects have somewhat degraded properties, but often are superior to many other materials, and have a variety of specialized applications such as refractories, electronic components, and catalyst substrates. In [1] there are articles discussing the future of alumina. There will continue to be incremental improvements in processing methods and properties, leading to expansion of present applications. What really new areas of application of alumina are likely These predictions are speculative, but the most promising new applications of alumina will probably be in electronic circuits, optical components, and biomaterials. Alumina fibers for composites and optics are attractive if they can be made pure, defect-free, and cheap. Because of its excellent properties other unsuspected applications of alumina will undoubtedly be developed. 

NANOCRYSTALLINE ALUMINA FIBERS STRUCTURE, PROPERTIES, APPLICATION... 

FIGURE 25.1 Technical application 1. Monazite on alumina fibers as a barrier layer in a ceramic-matrix composite. 

J. Dinwoodie, Saffil alumina fiber, manufacture, properties and application in high temperature furnaces, Canadian Ceramics Quarterly, 23-29, Feb. 1996. 

Thermal Insulation is by far the most Important present application of oxide fibers. Transition alumina fibers, e.g., eta-alumina fibers, are produced at Intermediate firing temperatures and are used as supports for catalysts and Insulation tiles such as those used for the space shuttle orbiter [1-2]. Carbon fiber felts are used as internal thermal insulation for vacuum furnaces at extremely high temperatures. Activated carbon fibers, which are obtained by partial oxidation of selected carbon fibers, have extremely small pores and very high specific surface areas, ranging from 500 to 3000 mVg. They are of great interest in ultrafiltration as membranes for the treatment of used waters and liquids [3-5]. 

All-oxide CMCs based on alumina fibers and matrices are favorable materials for use at high temperature in oxidizing atmospheres. One possibility for CMCs is the application as combustion liner. As a major drawback oxide fibers show the lowest creep resistance of all ceramic fibers due to their predominant ionic bonds. Therefore, the knowledge of the creep behavior becomes important for construction and dimensioning of components undergoing creep deformation over the life time. 

Whiskers are short fibers, usually a single crystal with an aspect ratio of 10/1 or greater. They have high strength but are difficult to process. Their applications so far has been limited SiC whiskers are reported as random reinforcement for ceramics and in alumina cutting tools. CVD is a common production method.O Beside SiC, the following whiskers have recently been produced by CVD ... 

Aluminum oxide (alumina), AI2O3, has lugh technological value. Sol-gel processing of alumina has created novel applications and improved some of its properties. Products such as catalyst earners, abrasives, fibers, films for electronic applications, aerogels, and membranes for molecular filtration have been developed based on sol-gel processing. See also Alumina Adsorption (Process) and Bauxite Aluminum and Aluminum Alloys and Engineered Materials. 

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