Electric and Electronic Ceramics

Advanced ceramics form the second largest sector of the industry. More than half of this sector is electrical and electronic ceramics and ceramic packages ... 

Engineering structural ceramics (32%) Electrical and electronic ceramics (21%) Capacitors, substrates, and packages (20%) Electrical porcelain (5%)... 

Electrical and Electronic Applications. Silver neodecanoate [62804-19-7] has been used in the preparation of a capacitor-end termination composition (110), lead and stannous neodecanoate have been used in circuit-board fabrication (111), and stannous neodecanoate has been used to form patterned semiconductive tin oxide films (112). The silver salt has also been used in the preparation of ceramic superconductors (113). Neodecanoate salts of barium, copper, yttrium, and europium have been used to prepare superconducting films and patterned thin-fHm superconductors. To prepare these materials, the metal salts are deposited on a substrate, then decomposed by heat to give the thin film (114—116) or by a focused beam (electron, ion, or laser) to give the patterned thin film (117,118). The resulting films exhibit superconductivity above Hquid nitrogen temperatures. 

In the broad range of ceramic materials that are used for electrical and electronic apphcations, each category of material exhibits unique property characteristics which directiy reflect composition, processing, and microstmcture. Detailed treatment is given primarily to those property characteristics relating to insulation behavior and electrical conduction processes. Further details concerning the more specialized electrical behavior in ceramic materials, eg, polarization, dielectric, ferroelectric, piezoelectric, electrooptic, and magnetic phenomena, are covered in References 1—9. 

Figure 23. Multichip package for a supercomputer. Top, unpopulated substrate with TFML copper-polyimide interconnections on a 100 by 100 mm multilayer ceramic substrate bottom, cross section of interconnection structure and flip-TAB carrier. (Reproduced with permission from reference 81. Copyright 1985 Institute of Electrical and Electronics Engineers.)...

Over the past 60 years ceramic magnets have become firmly established as electrical and electronic engineering materials most contain iron as a major constituent and are known collectively as ferrites . 

One fateful day in 1980, as the people down at the Institute of Electrical and Electronic Engineers like to tell the story, Rustum Roy, a physical chemist at Penn State, became disenchanted with his experiments in superconductivity, which is the ability of some substances, when cooled to very low temperatures, to conduct electricity without resistance and without loss. He had been experimenting for five years with ceramics—notably with a barium-lead-bismuth oxide mixture—but despite the long hours and the hard work, he could not get his concoction to superconduct at temperatures any higher than a few degrees above what one might encounter in outer space. 

The main representatives of this group are steatite, cordierite and forsterite ceramics. The prevailing crystalline phases in these materials are the minerals enstatite, cordierite and forsterite, which are also responsible for the main properties. All the materials find use in electrical and electronic applications where their insulating ability, as well as further specific properties are exploited. These are ... 

Of the 700 000 tons SiC produced per year, about 33% is used in metallurgy as a deoxidizing plus alloying agent, and about 50% in the abrasive industry [257]. The remainder is used in the refractory and structural ceramics industries and to a small extent also in electric and electronic industries as heating elements, thermistors, varistors, light-emitting diodes, and attenuator material for microwave devices. 

In comparison to conventional reactor systems, microreactors are easier to scale up by numbering-up (external or internal numbering). Most microreactors are made from silicon wafer or Si bulk using traditional semiconductor microfabrication methods, whilst other materials such as ceramic, glass and stainless steel have also been used in their design. The design of microreactors made from these materials is based on the application type, thermal conductivity, mechanical, electrical and electronic properties of each material. 

Electroceramics. A general term for ceramics specially formulated for electrical and electronic applications. 

Ferroelectric and piezoelectric ceramics, in particular, play an ever-increasing role as materials for electrical and electronic applications that include multilayer capacitors (MLCs), bypass capacitors, dielectric resonators for frequency stabilization of microwave circuits, low-noise oscillators and low-insertion loss bandpass filters for microwave communication components, dielectric waveguide resonators, piezoelectric transducers and sensors, piezomechanical actuators and motors,... 

The history of ceramics is as old as civilization, and our use of ceramics is a measure of the technological progress of a civilization. Ceramics have important effects on human history and human civilization. Earlier transitional ceramics, several thousand years ago, were made by clay minerals such as kaolinite. Modem ceramics are classified as advanced and fine ceramics. Both include three distinct material categories oxides such as alumina and zirconia, nonoxides such as carbide, boride, nitride, and silicide, as well as composite materials such as particulate reinforced and fiber reinforced combinations of oxides and nonoxides. These advanced ceramics, made by modem chemical compounds, can be used in the fields of mechanics, metallurgy, chemistry, medicine, optical, thermal, magnetic, electrical and electronics industries, because of the suitable chemical and physical properties. In particular, photoelectron and microelectronics devices, which are the basis of the modern information era, are fabricated by diferent kinds of optical and electronic ceramics. In other words, optical and electronic ceramics are the base materials of the modern information era. 

Ceramic materials offer mechanical and electrical properties that make them especially suitable for the electrical and electronics industries. The hulk of electrical ceramics are used either as insulators or as dielectrics. Electrical grade ceramics have more exacting property requirements than the ceramics used for refractory or structural purposes. Properties such as dielectric strength, dielectric constant, dissipation factor, and thermal and electric conductivity are closely related to microstructure as well as to composition and processing. 

Ceramics are subject to failure by thermal shock due to the disruptive stresses that result from the differential dilation between the surface and core of a body. With the relatively slow cooling rates usually encountered in most electrical and electronic applications and with the exception of materials with very low thermal expansion coefficients, the thermal conductivity usually determines the resistance of a ceramic to failure by thermal shock. Listed in Table 2.2 are the thermal stresses or shock resistances of several ceramics as derived from the relation R" = C oIccE, where C is the thermal conductivity, o is the tensile strength, a is the coefficient of thermal expansion, and E is Young s modulus. 

Vistal Registered trademark. Nominally 99.9% AI2O3. A translucent, high-purity alumina ceramic for highly critical electrical and electronic applications strong, excellent resistance... 

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