Advanced structural ceramic materials applications

Both gas turbine and process heat versions of the HTGR are based on the demonstrated high-temperature capability of the fuel and core structure. However, some development in the metallic components, such as the turbine, hot duels and intermediate heat exchanger is necessary, Present commercial alloys would have limited lifetime under service conditions at 1650°F (899°C) and above. However, currently envisioned advancements in ceramics and carbon-carbon composites indicate that high-temperature nonmctallic substitutes for metallic alloys will soon be available. These materials advances are the key to making future application of the IITGR a reality. 

Si3N4 ceramics cover only 1% of the total market of advanced ceramic materials, i.e., electronic and structural applications, but about 5% of the structural ceramics. They have the highest growth rates among structural ceramics [636-638]. 

Mandler WF (2001) Commercial Applications for Advanced Ceramics in Diesel Engines. In Singh M, Jessen T (eds) 25th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures A (Ceram Eng Sci Proc 22). Am Ceram Soc, Westerville, OH, p 3... 

Zirconia ceramics represent a fairly new class of advanced structural materials (see Zirconium and zirconium compounds). Their potential use in structural applications was first realized in the mid-1970s. Since then numerous publications have appeared devoted entirely to these materials ( 76—81). 

Clays will continue to be an important industrial mineral for the foreseeable future. Clays continue to be used widely as raw materials for refractories and other traditional ceramics because of their availability, low cost, and ease of processing. However, a majority of applications for clay minerals lie outside the field of ceramics, as summarized in Tables 10 and 11 and described in detail in several of the references [8,14,21 ]. Because of this breadth of applications and continued availability of easily-mined, high-quality clay deposits, the current level of production and utilization of clay minerals should continue [8], Production is currently stabilized around 40 million metric tons per year with an average price of approximately 30 per ton [8], More importantly for the modem materials community, understanding the processing and characterization of traditional ceramics can provide significant insight into the structure of the materials curriculum and the methods used to process and characterize advanced ceramic materials. 

The bulk of chemical vapor deposition, in terms of dollars of ultimate market, is directed to electronic applications. Although low cost added, high volume, applications may be found in structural ceramics, the high value added, multi-use environment of electronic materials has driven much of the search for advances in chemical vapor deposition. 

The past two decades have brought advances in many sectors and led to a much larger number of ceramic products as well as completely new applications, particularly in the technical field. On an initiative within the German Ceramic Society (DKG), professors and other experts reviewed the classification of ceramic materials at the end of 2004. They decided that the structure had been too detailed in some cases whereas it would be sensible make additions in other fields. This applies particularly to electrical ceramics, where the differences between products with active and passive functions are now so great that these are now divided into two main groups. 

Despite the development of advanced ceramic materials possessing enhanced properties, the widespread use of these materials for structural applications has been limited mainly because of the high cost of machining by grinding. In the manufacture of ceramic components, grinding can comprise up to 80% of the total cost [1]. Efficient grinding requires selecting... 

Visualization of Domain Structures by CL Spectroscopy. In addition to the capability to rapidly screen and evaluate residual stress characteristics in advanced ceramic materials and structures, exploration of new applications for the CL technique has been concurrently carried out. On the basis of the lattice dependence of CL spectra, we extensively applied CL microscopy to ferroelastic ceramics in order to obtain a widened body of structural information in a conventional scanning electron microscope, thus proposing this technique as more advantageous in terms of both spatial resolution and scanning flexibility above other spectroscopic methods. 

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