Ceramic-Clad Ceramic System for Ultrasonic Wave Guidance

Ceramic-clad ceramic components were developed to address the need for buffer rods capable of operating under severe conditions. The buffer rods were produced using plasma spraying to build up a 500-nm thick layer of alumina on a solid alumina rod. Both conventional plasma spraying and high power plasma spraying techniques were employed to deposit the alumina coating directly onto a pre-roughened surface. Characterization of the resulting coatings indicated a level of porosity of several percent, substantially higher than that of the dense core. The room temperature wave propagation characteristics exhibited by these clad buffer rods were significantly improved over that of the unclad components.