Barium-based glass

In addition to the aforementioned interactions with the surrounding gas environments, metallic interconnects also interact with adjacent components at their interfaces, potentially causing degradation of metallic interconnects and affecting the stability of the interfaces. One typical example is the rigid glass-ceramic seals, in particular those made from barium-calcium-aluminosilicate (BCAS) base glasses [205-209], FSS interconnect candidates have been shown to react extensively with... 

In addition to the blend of monomers, composite resins contain fillers. These are typically finely divided quartz or barium silicate glasses, and their function is to provide strength for the fully formulated composite [2]. These fillers are linked to the polymer phase by coupling agents, which are typically silane-based substances [2]. Composite reins are characterized by the absence of a chemical reaction between the filler and the monomer or polymer phase. Also, they show no inherent adhesion to the tooth but instead they have to be bonded to the tooth with bespoke bonding agents. These are discussed in detail in Chapter 5. 

The development of glass-ceramics with a barium disilicate primary crystal phase was conducted in two diflFerent ways. The first type of glass-ceramic was produced from base glasses with a composition almost corresponding to the stoichiometric composition of barium disilicate. The second type of glass-ceramic with sanbornite crystals was developed from multicomponent glasses using controlled crystallization. 

James (1982) determined the influence of phase separation on the kinetics of nucleation and crystallization in base glasses. He showed that glasses of the stoichiometric composition of barium disilicate (33.3 mol% BaO, 66.7 mol% Si02) demonstrated the highest nucleation rate compared with other... 

Leppavuori et al., Electrical Properties of Thick Film Capacitor Based on Barium Titanate Glass Formulation, Thin Solid Films, vol. 86, pp. 287-295,1981. 

Olin- Winchester Chlorate Base Copper, zinc, potassium chlorate, lead thiocyanate, paper, calcium silicide, barium nitrate, glass powder It is unlikely that the amount of particles that someone would be exposed to from firing would be sufficient to cause any of these effects. ... 

Three new low-sodium, barium, and boron-free silica-based glass-ceramic sealants were developed doped with magnesium (SACNMg), lanthanum-zinc... 

Barium-Magnesium-Strontium-Based Glasses/Electrolyte Interface... 

Radiopaque materials are used to determine the location of aspirated dentures and fragments (205,206). Opacifying additives include barium sulfate, barium fluoride, barium or bismuth glasses, and brominated organic monomers and polymers. The incorporation of these additives into the resin base or tooth can adversely affect physical properties. Radiopaque materials meeting the requirement for ANSI/ADA specifications for denture-base polymer have been described (207). 

Polymerizations. The polymerizations were carried out in an argon atmosphere in capped glass bottles fitted with a neoprene rubber gasket inner liner. In charging the polymerizations, the order of addition of materials was solvent first, then metal alkyls, next the barium salt, and finally the monomer(s). The amount of metal alkyl charged was sufficient to titrate the acidic impurities present in the solvent and polymerization bottle, plus the calculated amount for initiation of polymerizations. The mole ratio of barium to metal alkyl(s) was based on the moles of total alkalinity of barium to the moles of carbon-metal assayed. Unless otherwise stated,... 

Many barium aluminosilicate-based compositions will eventually react with the chromium oxide or aluminum oxide scales on the metal interconnect or metal edge rails to form barium chromate or a celsian phase at the interface [6], This can cause a mechanical weakness that is easily delaminated. Also, compositions that contain boron can react over time with water (steam) to produce B2(OH)2 or B(OH)3 gas. This can decompose the glass and greatly limit the lifetime of the seal. Thus many of the new investigations have emphasized low or no boron glass compositions. 

Z.G. Yang, K.S. Weil, K.D. Meinhardt, J.W. Stevenson, D.M. Paxton, G.-G. Xia, and D.-S. Kim, Chemical compatibility of barium-calcium-aluminosilicate base sealing glasses with heat resistant alloys, in Joining of Advanced and Speciality Materials... 

Z. Yang et al., Chemical Compatibility of Barium-Calcium-Aluminosilicate-Based Sealing Glasses with the Ferritic Stainless Steel Interconnect in SOFCs, Journal of the Electrochemical Society, 150(8), pp. A1095-A1101 (2003). 

---