 |
Comparison of piezoelectric and EMAT technologies for ultrasound generation and reception |
|
|
PIEZO |
EMAT |
|
Surface contamination of the test object |
not permissible |
no effect |
|
Testing of objects moving at high speed |
typically up to 1.5 m/s |
no limitations |
|
Curvature of the test object |
significant effect |
no effect |
|
Low temperature of the object or environment |
not permissible |
no limitations |
|
Hot and very hot objects (up to 1200 °C) |
typically up to 90 °C |
supported |
Note:
1* — the practical limit is 15 m/s under restricted testing conditions and with special measures to stabilise acoustic coupling;
2* — up to 300 °C with special measures to provide acoustic coupling and at reduced throughput; not in widespread use.