Investigation of Electronic Ceramic Fibers for Non-Destructive Evaluation of Advanced Composites.
Abstract : A discussion is presented on the feasibility of developing and using crystal-bearing filaments as sensors in the non-destructive evaluation of fiber-reinforced plastic structural materials. The fibers or filaments contain crystalline oxidic materials commonly referred to as electronic ceramics. Compositions investigated include ferroelectric potassium sodium niobate, lithium niobate, lead germanate, lead germanium silicate, lead zirconate titanate, and a magnetic ferrite. These electronic ceramic compositions were dissolved in compatible molten glass, shaped, annealed, and cooled to room temperature. The test shapes (filaments and disks) were then heat- treated to precipitate (exsolve) the material that had been put in solution. Progress is reported in the preparation and processing of these materials. Devitrified filaments were incorporated into test composites, with an epoxy-novalac matrix, and were subjected to preliminary electrical measurements. The effects of glass content and microstructure on electrical properties are reported. (Author, modified-PL)