Ceramics in General

Japan is the United States chief competitor in ceramics. There is a widespread but false perception that Japan leads the United States in ceramics in general. Nevertheless, it is clear that the Japanese effort in ceramics is comprehensive and long term and that several Japanese companies lead their U S. industrial counterparts in specific technologies. There is tremendous enthusiasm in Japan for the potential of ceramics, and a recent report of a U S. visiting team to Japan reached the following conclusions ... 

The simplest way to determine the grain size distribution is with the help of the sieve tower. This method is decribed in the chapter Ceramic in general / mass preparation . 

See the chapters Colloid chemistry and Ceramics in general / shaping . 

Plastic clay is used in, for example, the manufacture of bricks and roof tiles. Each product requires a specific clay with a specific plasticity. In the chapter on clay and in the section on moulding (chapter 9, Ceramic in General) the subject was already discussed. 

Nuclear magnetic resonance (NMR) is used for a variety of purposes in this area, most of which parallel those used to characterize small-molecule systems.17,24 In addition to II and 13C NMR, 29Si NMR is very frequently employed. These methods are used to characterize chemical composition, structural features, and conformational preferences. They are also used to characterize hybrid inorganic composites, and silica-type ceramics, in general. 

Ceramics in general have lower a values than metals. 

Why consider dislocations in ceramics Conventional wisdom says that dislocations are not nearly as important in the mechanical deformation of ceramics as they are for metals. The reason is that dislocations in ceramics do not move as easily as those in metals and they are usually not as numerous. So we should be asking why the last sentence is true. Dislocations in ceramics are extremely important because of what they do not do they do not glide easily. Si devices would not work for long and ceramics, in general, would not be brittle if dislocations could glide easily. Understanding dislocations also helps us understand other more complex defects, how they interact with point defects, and how they can cause planar defects. Dislocations become very important when we use thin crystalline ceramic films, particularly when grown on crystalline substrates. 

There is the problem of specimen preparation for analysis of interfaces in ceramics. In general, we cannot prepare a sample without altering the GB in some way. 

The fabrication of refractory carbides and nitrides (and ceramics in general) entails two major steps (a) pressing the powder to the required shape and (b) sintering (or firing) it at high temperature. 

With relatively transparent ceramics, in general k 4n and Eq. (12) becomes... 

A great many parameters affect the degradation behavior of hydroxyapatite and ceramics in general, including composition (Ca/P ratio), purity, morphology and site of deposition in the body [341]. The degradation into calcium and phosphate ions is mainly a solution-driven process that depends on the surrounding environment and cell mediators [342]. 

Two important groups of ceramics have silicon nitride SijN as the main component Both are characterized by better toughness than ceramics in general. The first product is pressure-sintered silicon nitride SijN (Figure 44.4). 

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