Experimental evaluation of clad metallic buffer rods for high temperature ultrasonic measurements

The fabrication, evaluation and several applications of metallic buffer rod s consisting of a core and a cladding are presented. The clad rods can have a taper shape and the cladding is fabricated by thermal spray techniques. Clad rods as long as Im have been fabricated. Experimental results show tha t the ultrasonic signals detected at 5 MHz with these buffer rods have very high signal to noise ratio (>35 dB) for both longitudinal and sheer waves in a reflection mode. Applications to the measurement of the thickness of h ot plates and molten metals up to 960 degrees C and to the on-line monitori ng of polymer extrusion are reported. Crown copyright (C) 2000 Published by Elsevier Science Ltd. All rights reserved.