Which material is more likely used as a mounting material for a probe coil?

Fiberglass is often used as a mounting material for probe coils in Eddy Current Testing due to its favorable properties. It provides excellent insulation, which is important when working with electromagnetic fields and electrical components. Fiberglass has a low thermal conductivity, meaning it doesn't easily allow heat to dissipate, which helps protect sensitive components of the probe and maintain their performance during testing. Additionally, fiberglass is lightweight and resistant to corrosion, making it a practical choice for various testing environments.

Other materials like aluminum and copper, while having their own benefits in electrical conductivity, may not serve well as mounting materials due to their conductive nature, which could interfere with the operation of the probe coil. Steel, on the other hand, is typically too heavy and can also affect the magnetic fields necessary for Eddy Current Testing, making it less suitable for this application.