Abstract: An article is disclosed in one embodiment of the invention as including a silicon-based ceramic substrate and a top coat. A bond coat is provided between the silicon-based ceramic substrate and the top coat. The bond coat is derived from a mixture containing preceramic polymer precursors, such as polycarbosilanes, polycarbosilazanes, or other silicocarbon polymers and pyrolyzed preceramic polymer precursors. A filler material may also be included in the mixture to modify the coefficient of thermal expansion (CTE) of the bond coat to more closely match the CTE of the silicon-based ceramic substrate, top coat, or both.

Abstract: A seal located between ceramic electrolyte or mixed electrolyte cells, and ceramic components of similar or dissimilar compositions, ceramic components and metal components, or any other materials for use in electrochemical gas separation devices, fuel cells and other thermal electrochemical power generation devices, high temperature heat exchangers, thermal management devices or other applications requiring joining or gas-tight bonding where said seal is comprised of materials derived from pyrolysis of silicocarbon polymers and fillers of active and/or passive fillers.