Composite materials organic-ceramic/glass composites

Ceramic-glass composite materials may be used to economically fabricate very complex multilayer interconnection structures. The materials in powder form are mixed with an organic binder, a plasticizer, and a solvent and formed into a slurry by ball or roll milling. The slurry is forced under a doctor blade and dried to form a thin sheet, referred to as green tape or greensheet. Further processing depends on the type of material. There are three basic classes of materials high temperature cofired ceramic (HTCC), low temperature cofired ceramic (LTCC), and aluminum nitride. 

Recently, interesting composite materials incorporating polymeric materials into the sol-gel glasses have been reported by Wilkes and his co-workers [9]. These materials are named ceramers . The properties of ceramers strongly depend on the reaction conditions, i.e., acidity, water content, reaction temperature, the amount of organic polymer, the molecular weight of polymer, solvent, and so on. 

Molecular hybrids between organic polymers and silica gel are expected to show many possibilities as new composite materials. First, the hybrids may show intermediate properties between plastics and glasses (ceramics). In addition, the composition of the hybrids can be widely varied. In other words, the hybrids can be used to modify the organic polymer materials or to modify the inorganic glassy materials. The hydrophilic modification as described before is a typical example. 

Composites based on glass fibre, known as GRP, have been available for five decades. Estimated consumption in 1990 was very approximately 1,000,000 tonnes each in Western Europe and USA and 450,000 tonnes in Japan. Much less composite material based on organic, carbon and ceramic fibres is used, approximately 12,000 tonnes worldwide in 1990. However, the properties of these fibres are such that composites produced from them, known as advanced composites, are extensively used in aerospace, high performance engineering and sports goods. Consequently, though the volume market may be small, the value of the products is very substantial. 

Organic-ceramic composites may use an epoxy as the matrix and glass or ceramic powder as the filler. A common example is the fiberglass-reinforced epoxy used as a printed circuit laminate. An epoxy substrate filled with alumina and carbon black has also been developed. By weight, the composition is 10.8 percent epoxy resin, 89 percent alumina, and 0.2 percent carbon black. This material has a thermal conductivity of 3.0 to 4.0 W/(m K), compared to both glass-epoxy printed circuit material [0.2 W/(m K)] and glass-alumina low temperature cofired substrates [2.5 W/(m K)]. The TCE (17 ppm/°C) is substantially below that... 

By definition, composite materials are solids resulting from the combination of two or more simple materials that develop a continuous phase (polymer, metal, ceramic, etc.), and a dispersed phase such as glass fibers, carbon particles, silica powder, clay minerals, etc. In addition, they have properties that are essentially different from the components taken separately. Within the large amount of inorganic-organic hybrid materials, nanocomposites are an emerging group that established a vast attention mainly due to their potential in industrial applications [1]. 

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