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- since 1996 -

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Technical Discussions
Sam Moore
Sam Moore
03:19 Nov-14-2002
Ultrasonic Testing Porous Ceramics

I am trying to measure the velocities of ~20% porosity zirconia. I am having no luck, any suggestions.


 
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Tom Nelligan
Engineering,
retired, USA, Joined Nov 1998, 390

Tom Nelligan

Engineering,
retired,
USA,
Joined Nov 1998
390
05:16 Nov-15-2002
Re: Ultrasonic Testing Porous Ceramics
: I am trying to measure the velocities of ~20% porosity zirconia. I am having no luck, any suggestions.
.

Porous ceramics are indeed very hard to penetrate, but if the thickness is less than 150mm or so you can probably get through your material with a low frequency through transmission setup. You'll need a pair of transducers in the 50 KHz to 200 KHz range, along with a high gain pulser/receiver or flaw detector.

--Tom Nelligan


 
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Neil Gibson
Neil Gibson
00:21 Nov-17-2002
Re: Ultrasonic Testing Porous Ceramics
: I am trying to measure the velocities of ~20% porosity zirconia. I am having no luck, any suggestions.
.

We (CNS Farnell) supply a simple unit (known as the PUNDIT) which is widely used for measuring pulse velocities in concrete and ceramics. One of our basic units plus some of our 150kHz transducers should probably do the job. Contact me on +44 20 8238 6900 for more details, or have a look at our website.




 
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Otto Kroggel
Otto Kroggel
08:40 Nov-18-2002
Re: Ultrasonic Testing Porous Ceramics
: I am trying to measure the velocities of ~20% porosity zirconia. I am having no luck, any suggestions.
.
The relative volume of pore does not describe the problem sufficiently.
It would be helpful to know the pore size distribution or at least the medium pore size to give a reliable
advice, based on my experiences with concrete and ceramics.
What is the nature of the surface ?
Are coupling media applicable or will they fill the pores and create erraneous velocity measurements?

Best results in concrete inspection come from transduver arrays using shear waves.

Best regards Otto Kroggel





 
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M. Kim Joihnson
M. Kim Joihnson
08:10 Nov-18-2002
Re: Ultrasonic Testing Porous Ceramics
: : I am trying to measure the velocities of ~20% porosity zirconia. I am having no luck, any suggestions.
: .
: The relative volume of pore does not describe the problem sufficiently.
: It would be helpful to know the pore size distribution or at least the medium pore size to give a reliable
: advice, based on my experiences with concrete and ceramics.
: What is the nature of the surface ?
: Are coupling media applicable or will they fill the pores and create erraneous velocity measurements?
.
: Best results in concrete inspection come from transduver arrays using shear waves.
.
: Best regards Otto Kroggel
.
.If the porosity is evenly distributed and the pore size is very small compared to the sample size, we may be able to make the measurement using Resonant Ultrasound Spectroscopy. Please visit www.quasarintl.com and look under "RU Spec," and contact me if you think appropriate.



 
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