What ultrasonic couplant to choose, depending on your needs
Are you looking to buy an industrial ultrasonic couplant but you do not know what type to choose? If you find yourself in this situation, there is no need to worry. You only have to continue reading this article in order to find out what type of couplant to buy, depending on your needs.
- Propylene Glycol
This type of couplant is a common purpose one that is used in temperatures as high as 90° C. Those are mostly used on smooth surfaces for thickness gaging applications. Because this industrial ultrasonic couplant is widely used, it can be easily found at your local chemical supplier.
- Glycerin
Glycerin, as Propylene Glycol is a general purpose couplant, but because it is more viscous and has a higher acoustic impedance, it can also be used on rough surfaces. A great disadvantage of this couplant is that it can be hard to remove from the test surface, and when used with metal, it can promote corrosion. This is why it is usually used to test materials such as plastic, fiberglass, and composites.
- Gel
As a consequence of the fact that gel couplants have a high acoustic impedance, and also because, as Glycerin, these are viscous, they are mostly used for inspecting rough surfaces. Unlike the other two types of couplants presented above, gel can be easily spread on large surfaces, and these also give you the possibility of sliding the transducer across a wide area. These two main advantages make gel the preferred ultrasonic couplant for inspecting welds.
- Ultratherm
This is the type of couplant you should look for if you need testing at high temperatures. This happens because it does not release fumes, burn, or boil off at high temperatures. This semi-solid paste couplant can be used in temperatures as high as 520°C.
