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 -

IMG ULTRASUONI SRL
Ultrasonic transducers for industrial applications (NDT) and medical (Doppler effect). Probes, Ultrasonic instruments, Special systems for NDT.

394 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

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.
>

Robotic laser shearography enables 100% inspection of complex, flight-critical composite structures

An article in “Composites World Magazine” showcases Non Destructive Testing of aero-structures
...
with Laser Shearography. Over the years Dantec Dynamics has supplied many solutions for the aerospace industry. Referring to specific customer projects several of these cases are examined to outline the advantages of using Laser Shearography for automated defect detection.
>

FAAST-PA! OEM Patented phased Array for high speed UT inspection

Multiangle, Multifocus, Multifrequency, Multibeam. Instead of stacking UT electronics and having m
...
any PA probes, FAAST-PA is able to transmit all delay laws within ONE single shot in Real time.
>

NDT Master Lecturer

In the program both university professors and practitioners will give lectures, which guarantees the
...
oretical depth and practical inside. Academic Director: Prof. Dr. Christian Boller
The following lecturers are not complete: Prof. Tadeusz Stepinski, Prof. Wieslaw Staszewski, Prof. Frank Walther, Prof. Giovanni Bruno, Prof. Gerd Dobmann, Prof. Philippe Guy
>

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