Crystallized glass ceramic composite

LTCC Glass/Ceramic composite Crystallized glass Crystallized glass/Ceramic composite Liquid-phase sintered ceramics 900 to 1,000 Cu 1,083... 

FIuorosihca.tes, Compared to the simple sUicates, these crystals have more complex chain and sheet stmctures. Examples from nature iaclude hydrous micas and amphiboles, including hornblende and nephrite jade. In glass-ceramics, fluorine replaces the hydroxyl ion fluorine is much easier to iacorporate ia glass and also makes the crystals more refractory. Eour commercial fluorosUicate glass-ceramic compositions and thek properties are Usted ia Table 2. 

Rouxel, T., Verdier, P. (1996), SiC particle reinforced oxynitride glass and glass-ceramic composites crystallization and viscoplastic forming ranges , Acta Mater., 44, 2217-25. 

Although modulus of rupture is a useful comparative measure if surface conditions are specified, fracture toughness is a more useful property, especially for the development of glass ceramic compositions and crystallization heat treatments. 

The most important glass-ceramic compositions are probably based on lithium silicates. The phase diagram of the Li20-Si02 system is shown in Fig. 9.16. The commercial compositions usually contain more than about 30 percent lithia which upon crystallization yields Li2Si205 as the major phase with some Si02 and Li2Si03. 

The potential range of glass ceramic compositions is fairly broad because the method depends only on the ability to form a glass and to control its crystallization. However, almost all glass ceramics developed so far are based on silicate glass compositions. They include... 

For investigations on surface crystallization a glass ceramics composition close to the composition of Schott glass ceramics 8562 was chosen. Volume... 

As we explained in Chapter 1, the main types of LTCC dielectric ceramics are glass/ceramic composites and crystallized glass. The characteristics required of the raw materials differ for each type. 

In crystallized glass type LTCCs, since one kind of ceramic powder is used, it is not necessary to consider its charging characteristics. However, in order to achieve a homogenous structure, it is desirable to have a sharp distribution of particle size, and it is necessary to decide the powder particle size and specific surface area taking into account formability and sinterability in the same way as with glass/ceramic composites. 

Metastable synthetic (or modified) simulated body fluids (SBFs), with an inorganic salt composition similar to that of human blood plasma, incubate and faciUtate the spontaneous nucleation and growth of nanosized, carbonated and bone-like apatite at physiological pH and temperature. SBFs were first used by Kokubo andTakadama (52) in biomimetic synthesis to prove the similarity between the in vitro and in vivo behaviors of certain glass-ceramic compositions. Some typical SBF compositions are listed in Table 12.1. In these studies, the glass-ceramic samples were soaked in SBF solutions and their surfaces coated with a poorly crystallized calcium-deficient and carbonatebone apatite. A metastable SBF has been proven to incubate and facilitate the... 

Glass-Ceramics Based on Silicate Crystals. The principal commercial glass-ceramics fall into this category. These can be grouped by composition, simple siUcates, fluorosiUcates, and aluminosihcates, and by the crystal stmctures of these phases. 

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