portable coating thickness measurement

[Arturas]

Hello,
I am interested in portable coating thickness measurement instrument for thermal spray coating: all type cermet coatings WC/Co, CrC/NiCr; ceramic coatings Al2O3, Al2O3/TiO2; carbon steel; stainless steel, Mo ; self fluxing NiCrBSi coating and ?. on carbon steel, stainless steel and cast iron substrates. Can anyone to help?
Thanks

[Gordon]

Hi Aturas

There are many portable electronic thickness measuring devices out there. Ideally, the ones using both magnetic and eddycurrent methods would best suit your needs. Select the models that cover your particular thickness measuring range. These devices are good for:

• non-magnetic coatings on ferromagnetic substrates like aluminium on steel
  
• non-electrical conductive coatings on conductive substrates like ceramic on austenitic (non-magnetic) stainless steel
  

You will find that these instruments will not work with every coating/substrate combination though. Always calibrate and test on specific coating/substrate materials before relying on their readings.

The measurement of metals on non-ferrous metal substrates is not easily achieved using eddy-current method unless there is a 3:1 ratio in the conductivity between substrate and coating. The calibration of instruments must be carried out using samples of the materials with known thickness. Such instruments do not use the normal calibration characteristics and would have to be specially made for the specific coating and substrate.