couplant

plural couplants

1. a material that facilitates the transmission of ultrasonic energy from the transducer into the test specimen.

   The primary design challenge using fluid couplants is providing proper sealing so that the fluid does not leak out over time. One approach is to pot the lenses into their cells.

   1996, Sandra M. Faber, The design and assembly of camera lens cells for fluid couplants using elastomeric lens mounts

   1 more example

   There are many suitable substances that can be used as couplants, the main criteria being the best possible match and no adverse chemical reaction between the couplant and the metal.

   2001, Chuck Hellier, Handbook of Nondestructive Evaluation, pages 7–13