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 -

819 views
Technical Discussions
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1252

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1252
02:35 Sep-06-1996
Pulser de-polarization

Lately PC style Pulser-receivers have provided a
selection of pulse shaping features such as positive,
negative or bipolar (as well as energy level, duration,
etc). Traditionaly a negative spike or squarewave
pulse has been used on transducers. Is it possible
to deteriorate polarization of poled piezoceramics
using positive squarewave pulsing?





    
 
 
Bill Grandia
Bill Grandia
02:24 Sep-07-1996
Re: Pulser de-polarization
: Lately PC style Pulser-receivers have provided a
: selection of pulse shaping features such as positive,
: negative or bipolar (as well as energy level, duration,
: etc). Traditionaly a negative spike or squarewave
: pulse has been used on transducers. Is it possible
: to deteriorate polarization of poled piezoceramics
: using positive squarewave pulsing?

It is known that a piezo-electric element always ages with time, especially in the first few weeks after manufacturing, even without operating the element.
When operating the element with a driver voltage opposed to the polarization direction, the deterioration speed in enhanced. For this reason, it is expected that the positive portion of the bipolar square wave driver acts destructively. From experience, driving a PZT5A element with a toneburst (400 kHz, 16 cycles at 500 Hz PRF) over a period of several years, no noticeable deterioration has been noticed.





    
 
 
Gerhard Splitt
R & D, -
Private, Germany, Joined Nov 1998, 38

Gerhard Splitt

R & D, -
Private,
Germany,
Joined Nov 1998
38
03:22 Sep-08-1996
Re: Pulser de-polarization
: : Lately PC style Pulser-receivers have provided a
: : selection of pulse shaping features such as positive,
: : negative or bipolar (as well as energy level, duration,
: : etc). Traditionaly a negative spike or squarewave
: : pulse has been used on transducers. Is it possible
: : to deteriorate polarization of poled piezoceramics
: : using positive squarewave pulsing?

: It is known that a piezo-electric element always ages with time, especially in the first few weeks after manufacturing, even without operating the element.
: When operating the element with a driver voltage opposed to the polarization direction, the deterioration speed in enhanced. For this reason, it is expected that the positive portion of the bipolar square wave driver acts destructively. From experience, driving a PZT5A element with a toneburst (400 kHz, 16 cycles at 500 Hz PRF) over a period of several years, no noticeable deterioration has been noticed.

The depolarization with a "wrong" pulser polarization only occurs at high values of the electric field strength which then will act as a depolarization field
This is true only for high frequncy piezoceramic (above 10 MHz) and for high pulser voltages (over 500 Volts).
Therefore it is clear that at 400 kHz with a tonburst pulser no deterioration effect was observed.
Of course, at elevated temperatures the depolarization will occur at lower critical values.

Gerhard Splitt



    
 
 

Product Spotlight

Immersion systems

ScanMaster ultrasonic immersion systems are designed for high throughput, multi shift operation in a
...
n industrial or lab environment. These fully integrated systems provide various scanning configurations and incorporate conventional and phased arrays technologies to support diverse applications, such as inspection of disks, bars, shafts, billets and plates. All of ScanMaster immersion systems are built from high accuracy scanning frames allowing for scanning of complex parts and include a multi-channel ultrasonic instrument with exceptional performance. The systems are approved by all major manufacturers for C-scan inspection of jet engine forged discs. Together with a comprehensive set of software modules these flexible series of systems provide the customer with the best price performance solutions.
>

I&T Nardoni

NDT, RESEARCH AND DEVELOPMENT OF NEW METHODOLOGY, TRAINING CENTER I&T NARDON INSTITUTE was idiated
...
in 1988 by Giuseppe Nardoni, now president and owner of the company, based on his multi-annual and international experience in the field of NDT.
>

AIS229 - Multipurpose Real Time System

Latest standard & automatic real time system developed by Balteau. The AIS229 has been designed to
...
do series inspection in a wide variety of industry. Composed of a shielded cabinet, 5 axis manipulator, x-ray generator and tubehead from 160kV to 225kV, a fl at panel & much more, the AIS229 is most certainly one of the most multipurpose RTR system available on the market.
>

Panther

M2M PANTHER is a phased-array equipment designed for both desktop and industrial applications, offer
...
ing unparalleled performance in a compact unit. It combines the speed required for industrial integrated Phased-Array Ultrasound (PAUT) solutions, with the most complete set of total focusing method (TFM) imaging techniques, making it the ultimate tool for R&D and procedure qualification.
>

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