Rigid ceramic seals

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... 

The various options for sealing and joining the ceramic and metal components in pSOFCs can be broadly classified into one of three categories rigid bonded seals, compressive seals, and bonded compliant seals. As outiined in Table 11.2, rigid... 

The matching of expansion behavior is of the utmost importance to manufacturers of, for example, multi-layer capacitors, porcelain enameled cast iron sinks, fiber reinforced composites, light bulbs, etc. In all cases, various materials in rigid contact must have their expansion characteristics carefully matched. Inattention to this runs the risk of cracking and shattering of a light bulb at its seal to aluminum, delamination of metallic conductive leads from the ceramic substrate in a hybrid circuit, etc. By changing the composition of a constituent material, its... 

The test was run for a total of 100 hours. The preconverter was cycled back to room temperature and inspected at 5-hr intervals 19 times, with no failure detected in the mounting system. The ceramic substrate maintained its original position, the seals rigidized and remained attached to the mat, and the mat was not eroded. Given the low GTE of EX-22 substrate and the low temperature gradients in the close-coupled location, thermal durability did not pose a problem. 

The glass transition temperature lies considerably above the temperature of use with rigid foams and considerably below the temperature of use with flexible foams. The cellular structure may be open, closed, or mixed. All cells are open to each other with open cellular structures. In contrast, each cell is sealed off or encapsulated from the other cells by a plastic wall in closed-cell structures. Structural foams are foams with a dense outer skin and an interior of lower density they are also called integral foams or self-skinning foams. In contrast to normal foams syntactic foams do not directly enclose the gas but contain small hollow bodies of glass, ceramics, or plastics which are under vacuum or are filled with a gas. 

The satisfactory sealing of Na/S cells is another difficult technical problem It is necessary to provide three separate seals - to seal both the sodium and the sulphur electrodes from the atmosphere and also from each other In addition to being leak-tight, these seals must be chemically and electrochemically compatible with the reactants they contain (sodium and S/Na S, respectively) at temperatures up to 400 C and for periods of several years Ideally, the seals will have some flexibility to compensate for the rigidity and brittle nature of the ceramic tube ... 

In recent years, therefore, development of rigid and elastic sealants on the basis of metals and ceramics was initiated. By using multiphase materials, one can adjust the elastic properties and wetting of surfaces in contact. More details concerning the various sealing materials under study today may be found in a review by Fergus (2005). 

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