C-scan imaging in molten zinc by focused ultrasonic waves

Ultrasonic images of a small steel object immersed in molten zinc at 600 de grees C are obtained with high spatial resolution using a focused ultrasoni c pulse-echo technique, The focused ultrasonic waves are generated by a sph erical acoustic lens which has been machined at the probing end of a clad b uffer rod. The backscattered echoes from the object surface have a signal-t o-noise ratio of 35 dB at 10 MHz in molten zinc. The ability to provide hig h spatial resolution measurements in molten metal is demonstrated by compar ing the results obtained in molten zinc with those obtained in water. (C) 2 000 Acoustical Society of America. [S0001-4966(00)01102-4].