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Ambient Couplant

Silver Bullet Couplants – for inspections that are almost impossible without the right couplant.

Many UT applications require a specialty UT couplant.  For difficult inspections that require high acoustic impedance, shear wave, reduced surface noise, extreme temperature range or extended service life for sensors, we have the right couplant.

High Impedance Couplant: A high impedance couplant typically has an acoustic impedance above 3.5 M Rayls.  Water based couplants typically have acoustic impedances between 1.5 and 1.8 M Rayls depending on the Glycerin content (0% glycerin at 1.5 M Rayls, 12% glycerin at 1.8 M Rayls, 100% glycerin at 2.4 M Rayls). 

The advantage of a high impedance couplant is that more of the acoustic energy is transmitted between the transducer (or delay line) and test object and less is reflected and scattered at the surface of the test object.  This is particularly important when:

  • The test object surface is very rough (porous cast iron, scale, rough grinding).
  • The contact area for the delay line or transducer is small (pencil point probes measuring pit depths).
  • Materials such as concrete which are high impedance, scatter acoustic energy and often have a rough surface.

There are currently two options for water-soluble, high impedance couplants:

  • Z+ MV, a medium viscosity Glycerin based couplant (which has an operating range of 0 to 200°F; however, its viscosity increases quickly with temperature below 45°F.
  • Z+ fluid– does not contain Glycerin and maintains a fluid viscosity down to sub-zero temperatures.

Normal Incidence Shear Wave Couplant:

Not to be confused with angle beam generated shear waves (which rely on refraction of a longitudinal beam), normal incidence shear wave transducers propagate the shear wave with the transducer perpendicular to the test object and do not rely on refraction.  A normal incidence shear wave couplant requires a very high viscosity, high elastic modulus to perform acceptably.  Currently there is one commercially available water-soluble couplant that meets this requirement: Echo Shear Wave Couplant

Flow Meter and Sensor Couplant:

For permanent or long-term use, a flow meter couplant should resist creep, have good resistance to weather and chemicals as well as a broad temperature range.  Water-based couplants are suitable only for short-term flow metering applications. Echo 8 ZH is not water-based and is an excellent couplant for flow metering sensors.

Cryogenic UT Inspection:

CryoSoniX is the only ultrasonic couplant for use in cryogenic applications such as refrigerated ethylene. With an operating range of -200˚ to 60˚F (-129˚ to 16˚C), CryoSoniX enables repeatable and reliable inspections.

Phased Array Wedge Couplant:

Forever Wedge is an ideal couplant for use between phased array or angle beam transducers and the wedge.  Forever Wedge couplant won’t leach out, is impervious to water and couplants and when applied correctly, often lasts the life of the wedge or until it is replaced.  Forever Wedge eliminates phased array element drop out due to wedge couplant failure.

VersaSonic Ultrasonic Couplant

VersaSonic Couplant

You may be aware that VersaSonic® has superior performance from -10 to 750°F, however, did you know:

  • VersaSonic is available in medium viscosity for optimal spread-ability and high viscosity to “stay in place” on a transducer, pipe or overhead surface.
  • VersaSonic is available in open-top 1 and 5-gallon pails (5-gallon dispensing pump included at no charge), 1 gallon and quart cubitainers.
  • VersaSonic is a versatile broad temperature couplant. The world’s largest producer of power generating equipment has standardized on VersaSonic for use at ambient temperatures due to its compatibility with their electronic components.
  • Refineries and heat treatment plants use VersaSonic because its useful service life is up to three times longer than competitive couplants at temperatures above 350°F.

Have a job where you need to spread the couplant in some areas but need it to stay in place in others?  Try our quart dual pack of both viscosities.

Testing above 750°FEchoTherm and EchoTherm Extreme are the only ultrasonic couplants with operating ranges above 850°F.

Check out our complete line of high temperature couplants online



Introducing EchoTrack™ a new high performance, economical ultrasonic couplant,


Echo Ultrasonics® has introduced EchoTrack™ ultrasonic couplant, an economical high performance ambient temperature ultrasonic couplant for flaw inspection and thickness gauging.  EchoTrack is compatible with most materials, has excellent ferrous corrosion inhibition and is formaldehyde and glycol ether free.  

EchoTrack has a broad operating range (18 to 180°F, -8 to 82°C), leaves a low level, easier to remove residue, is slow drying and is available in a medium and high viscosities.

For free samples, complete the sample request form and let us know what couplant you are currently using.