where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -
418 views
Technical Discussions
Tomás Gómez-Acebo
Tomás Gómez-Acebo
07:21 Sep-28-1999
Phase shift in measurement of oxide layer thickness

Dear colleages, I have recently joined your discussion forum.
I would appreciate comments or suggestions about this topic.
When measuring with a 25 MHz probe the magnetite layer formed into the tubes of steam boilers (about .2 to 1 mm thick), there is a phase shift between the two echos in the RF signal: the first echo from the steel-oxide interface, and the second from the final oxide interface. How can this be interpreted?
Additionally, is there any way to distinguish between the two sub-layers of the oxide? Both have very similar chemical composition but slightly different porosity and microstructure: the inner (in contact with the steel) is layered, and the outer has columnar magnetite grains.
In the time-domain signal it is impossible to see anything that suggests the interface between the sub-layers, but what about the frequency-domain, or something else?
Best regards
Tomas Gomez-Acebo


 
 Reply 
 
Paul A. Meyer
R & D,
GE Inspection Technologies, USA, Joined Nov 1998, 47

Paul A. Meyer

R & D,
GE Inspection Technologies,
USA,
Joined Nov 1998
47
00:46 Sep-28-1999
Re: Phase shift in measurement of oxide layer thickness
final oxide interface. How can this be interpreted?
: Additionally, is there any way to distinguish between the two sub-layers of the oxide? Both have very similar chemical composition but slightly different porosity and microstructure: the inner (in contact with the steel) is layered, and the outer has columnar magnetite grains.
: In the time-domain signal it is impossible to see anything that suggests the interface between the sub-layers, but what about the frequency-domain, or something else?
: Best regards
: Tomas Gomez-Acebo




 
 Reply 
 

Product Spotlight

Customized Probes and Transducers

With a strong development department and our own piezocomposite production, we accompany you from th
...
e first product idea to serial production. Our scientists are continuously researching new methods in the field of ultrasonic measurement technology. The progress achieved enables us to offer you optimal solutions.
>

NDTkit RT

NDTkit RT, TESTIA's Digital Radiography software The NDTkit product line software for X-ray analysi
...
s. NDTkit RT is a software benefiting from the Ultis kernel which is dedicated to radiographic image analysis. It offers a set of tools and filtering processes to assist RT operators in finding relevant flaws.
>

FMC/TFM

Next generation for Phased Array UT is here now with FMC/TFM! Have higher resolution imaging, impr
...
oved signal to noise ratio, characterize, size and analyze defects better with access to several wave mode views and save raw FMC data for higher quality analysis.  Some of the benefits are:
  • Beautiful Image! Easier to understand what you're looking at
  • Completely focused in entire image or volume
  • Much easier to define setups before inspection
  • Easier to decipher geometry echoes from real defects
  • Oriented defects (e.g. cracks) are imaged better
  • See image from different wave modes from one FMC inspection
  • FMC data can be reprocessed/analyzed without going back to the field
>

Silverwing RMS PA - Phased-array corrosion mapping

Eddyfi Technologies integrated two market leading solutions, Silverwing’s RMS and M2M’s instru
...
ments to provide a high-speed, remote access ultrasonic phased-array inspection system with live total focusing method (TFM).
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window