In this work, both the transducer and the sample under test are immersed in liquid in order to facilitate the transmission of the ultrasonic waves travelling through them.
The block diagram is also depicted in Fig. 1 (dashed line). For convenience and affordability, water was used as liquid during the tests. However, to avoid corrosion problems a corrosion inhibitor solution should be used instead of. In addition, ferrous P/M parts were used in the experiments although the ultrasonic inspection system is valid to inspect any P/M part type