Scanning Acoustic Microscopy (SAM)
Scanning acoustic microscopy (SAM), utilizes an ultrasonic wave to evaluate the quality of bonding between two materials. The bonded parts, such as a brazed joint, are placed in a water bath, and the ultrasonic probe is able to scan a wide area of the joint below using the water of the bath as a couplant.
A common use for SAM is to evaluate a brazed joint within a copper cooling plate containing channels for coolants such as water. The full surface of the cooling plate can be traversed and the scanned image will show any weaknesses in the braze that would allow leakage between neighboring channels.
In the same way, brazed joints between 6061 T6 aluminum plates that contain the cooling channels of an electrostatic chuck base plate can be evaluated.