Layered Oxide Structures as Interfaces

Segadaes et al. [79] Cooper and Hall [80] and Morgan and Marshall [81] have proposed the use of j3-aluminas, the related magnetoplumbite oxides, micaceous materials, and monazites as interface coatings for ceramic matrix composites. The principle 

Cooper and Hall [80] assessed from thermodynamic and experimental viewpoints the potential for synthetic mica to serve as the interface material in oxide-oxide composites. Natural micas contain water which renders them useless at high temperatures since their structure breaks down in the range 500-800°C. However, in synthetic micas it is possible to replace the OH ion with fluorine, i.e. P. This substitution increases the stability to temperatures exceeding 1200°C at ambient pressure [90, 91]. While this 

More recently, Morgan and Marshall have suggested that compounds having the monazite crystal structure may be useful oxidation interface coatings. Specifically, they recommend the compound LaP04. Their sol-gel experiments with this compound are encouraging. 

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