Title: NDE IN CERAMIC PROCESSING

Abstract:
The role of nondestructive examination (NDE), in a processing methodology that was developed to produce high reliability silicon nitride heat engine components is discussed. NDE techniques were utilized for In-process control of unit operations, as well as for assuring the quality of product during processing. The process employed a colloidal-consolidation strategy with "closedloop" aqueous powder comminution, slurry concentration and pressure casting. Microfocus radiography (MFX), ultrasonics (UT), computed tomography (CT), fluorescent liquid dye penetrant (LDP) and nuclear magnetic resonance (NMR) were some of the NDE techniques adapted to specific unit operations of the process. During the process development stage the NDE techniques were customized for use as characterization tools for establishing control variable-performance parameter relationships for various unit operations. Thereafter, they were used to monitor and control the unit operations. One example to be discussed involves control of the casting operation by monitoring the attenuation of a UT signal which is transmitted through the developing ceramic cake.
(Ref. SXVIII-004-97)

Source: NDE of Ceramics '97 May 4-7, Symposium on Nondestructive Evaluation of Ceramics at the American Ceramic Society 99th Annual Meeting, Cincinnati, Ohio.
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