dear all,

i am using ultrasonic microscopy to control the quality of the brazing layer between a coper part and a silver composite.

i controlled on a part without silvercoating and then after with silver coating (5µm) and with the same ultrasonic program (same FSF, same gate etc.) the welding defect on C-scan are more important, brighter with silver coating than without it.

For me it is not logical because a coating means more material that the ultrasonic wave needs to get through in, one more interface that can cause more reflection....

Sor for me the defects should have appeared darker and not brighter?

do you have any explanation?

thank you