Volume 25, Issue 3 (May 1997)
Material Specifications of Advanced Ceramics and Other Issues in the Use of Property Databases with Corrosion Analysis Models
The growing interest in linking analysis models with distributed materials property databases gives rise to new database design requirements. This paper discusses the conditions encountered in the modeling of the corrosion of a ceramic material as a time-dependent phenomenon. In the corrosion of ceramics, numerous distinct contributing processes occur in different regions of the specimen simultaneously. These different regions usually have different compositions, native microstructures, and environmentally intrusive agents. Both predictive modeling efforts and post-test diagnostic analyses, therefore, require chemical and physical property data that are related to the specific material substructures. There are significant problems in the practice of representing such information in general-purpose materials property databases. The essential issues pertain to the form of the representation, the accessibility of the data, and the uniqueness of the value set. This paper addresses these issues in the context of a multipurpose database into which access is needed by an automated, external, analysis program. The corrosion of silicon carbide is used as a prototypic case in discussing the standards for the database, the expectations of the user, and the implications of the practical design of the property database. It is concluded that the required analysis tools include the model with constraints on the material and the environment, a property database that distinguishes the material's substructure types and locations, a reactions database for all significantly reacting species in the system, and an expert system interface to assess the performance level options available by means of the property data.