Response of plasma sprayed alumina-titania ceramic composite to high frequency impact loading

The life of mechanical components used for tribological and other applications, where surfaces are exposed to different types of loading, can be significantly enhanced through deposition of ceramic/ceramic composite on the surfaces. Among various spray deposition techniques, plasma spraying is most widely used. However, coatings developed through this technique need to be evaluated for performances under different conditions. The main aim of the present investigation is to study the response of the plasma-sprayed alumina-titania (AT-13) ceramic composites subjected to high frequency impact loading, in both as-sprayed and microwave-treated (post-processed) conditions in terms of indentation scar dimension and acoustic emission (AE) signals emitted by the impulsed material. The significance of AE monitoring for evaluation of critical load and duration for the onset of cracking of spray deposits is illustrated. Results show critical load and duration for the onset of cracking as 10 N and 3 min, respectively, in both cases. Results are discussed with illustrations. © 2002 Elsevier Science B.V. All rights reserved.