Dielectric ceramics

Cera.micA.bla.tors, Several types of subliming or melting ceramic ablators have been used or considered for use in dielectric appHcations particularly with quartz or boron nitride [10043-11 -5] fiber reinforcements to form a nonconductive char. Fused siHca is available in both nonporous (optically transparent) and porous (sHp cast) forms. Ford Aerospace manufactures a 3D siHca-fiber-reinforced composite densified with coUoidal siHca (37). The material, designated AS-3DX, demonstrates improved mechanical toughness compared to monolithic ceramics. Other dielectric ceramic composites have been used with performance improvements over monolithic ceramics (see COMPOSITE MATERIALS, CERAMIC MATRIX). 

Ytterbium oxide is used in cored carbon rods for industrial lighting. The oxide also is used as an additive in special glasses. Other uses are in dielectric ceramics and special alloys. 

Gadolinium Oxide, Gd203, mw 362.52 wh to cream-colored powder, sp gr 7.407 at 15/4°, mp 2330° hygroscopic and absorbing C02 from the air in sol in w sol in acids except HF. Used in nuclear reactor control sods, neutron shields, catalysts, dielectric ceramics, filament coatings, special glasses and as P... 

Fortunately, they are several species of low-loss dielectric ceramics with tailored temperature coefficient of dielectric constant, which can be made lower than 1 ppm/K for a certain temperature window around room temperature. Physically, this can be accomplished either by intrinsic compensation of the temperature dependence of thermal volume expansion V(T) and lattice polarizability a(T) via the Clausius-Mossotti relation ... 

Kanai, H. et al. (1998) Effects of microstructure on insulation resistance degradation of relaxors, in Advances in Dielectric Ceramic Materials, Vol. 88, The Am. Ceram. Soc., 295-9. 

Freer, R. (1993) Microwave dielectric ceramics - an overview. Silicates Industriels 9-10, 191-7. 

Petrovskii, V. Y, Gorvits, E. 1., Borovinskaya, 1. P., and Martinenko, V. M., SHS silicon nitride An attractive powder for dielectric ceramic production. In Problems of Technological Combustion. Chemogoiovka, 5 (1981). 

Therefore the dielectric constant is changed with temperature and the resonant frequency will change with temperature, and the microwave devices cannot respond at a specific frequency if the dielectric materials in microwave frequencies show a large TCK and thermal expansion coefficient a due to the thermal expansion of dielectric materials and the temperature dependence of polarizability. In general, the a of dielectric ceramics, which is well known as the slope of the Cockbain equation, is about 10 ppm/°C. Therefore control of TCP can be achieved by adequate manipulations of TCK. It is an important requirement for practical applications to control the stable TCP, nearly zero, which is available to temperature-stable microwave devices. 

In microwave dielectric ceramics, the extrinsic dielectric loss dominates. However, the intrinsic losses shonld be stndied to control and predict the dielectric properties at microwave freqnencies. 

In addition to the use of heterometal alkoxides, metal alkoxides are often associated with more easily available precursors such as acetates for the SG route to multicomponent oxides. A number of such alkoxide acetate precursors [e.g., MNb2(/i-OAc)2(/i-OR)4(OR)6 (M = Cd or Mg), PbZr3(/t4-0)(/i-0Ac)2(/i-OR)5(OR)5, and Gd2Zr6(/i4-O)2(pi-OAc)6(/t-OR)l0(OR)i0 (with R = i-Pr)] were characterized (564) by X-ray crystallography. Their hydrolytic studies indicate their potential use as precursors for the synthesis of electrooptical materials, for example, Pb(ScNb)03 (PSN), and dielectric ceramics, for example, [PbMg1/3Nb2/303] (PNM). 

Use Neutron shields catalysts dielectric ceramics filament coatings special glasses TV phosphor activator lasers, masers, and telecommunication laboratory reagent. 

Use Special alloys, dielectric ceramics, carbon rods for industrial lighting, catalyst, special glasses. 

EINECS 215-234-0 Ytterbium (III) oxide Ytterbium oxide Ytterbium oxide (Yb203). Used in special alloys, dielectric ceramics, carbon rods for industrial lighting, catalyst, and special glasses. Solid soluble in dilute xids. Atomergic Chemetals Noah Chem. Rhone-Poulenc. 

In addition to dealing with magnetic ceramics, this chapter also deals with dielectric ceramics, such as ferroelectrics, for which the dielectric response is nonlinear. Ferroelectricity was first discovered in 1921 during the investigation of anomalous behavior of Rochelle salt. A second ferroelectric material was not found until 1935. The third major ferroelectric material, BaTi03, was reported in 1944. Ferroelectric ceramics possess... 

Keywords Sintering Microwave dielectric ceramic. Dielectric resonator. 

Effect of Doped Sintering Aids for Nd(Mgo.5Tio.5)03 Microwave Dielectric Ceramics Properties... 

V. M. Ferreira, F. Azough, J. L. Baptista, and R. Freer, Magnesium Titanate Microwave Dielectric Ceramics, Ferroelectrics, 133, 127-32 (1992). 

C. L. Huang and M. H. Weng, Improved High Q Value of MgTi03-CaTi03 Microwave Dielectric Ceramics at Low Sintering Temperature, Mater. Res. Bull., 36, 2741-50 (2001). 

H. Kagata, T. Inoue, J. Kato, I. Kameyama, Low-Fire Bismuth-Based Dielectric Ceramics for Microwave Use, Jpn. J. Appl. Phys., 31, 3152-55 (1992). 

Kassarjian, M. P., Newnham, R. E., and Biggers, J. V., Sequence of reactions during calcining of a lead-iron niobate dielectric ceramic. Am. Ceram. Soc. Bull., 64, 1108 (1985). 

Taking into account its possible appHcations such as gas sensors, dielectric ceramics, and photocatalysts, titanium dioxide (Ti02) has been extensively studied, and it has been shown that titanium oxide as anatase phase can be synthesized at room temperature without use of any previous or further thermal or hydrothermal treatment, performing hydrolysis and polycondensation processes in saturated metal chloride solutions. 

Song, Y Wang, F. Jiang, Z. 2003. Simulation of the influence of space ultraviolet and proton radiation on dielectric properties of BaO-TiOj microwave dielectric ceramics. Guisuanyan Xuebao, 31(1) 36—40. 

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