Does anyone knows what is the minimum thickness of metallic coating to avoid supstrata signal in XRD or EDS measurements.. For example, MoFe alloy on Fe supstrate.
For EDS the information depth depends mainly on the energy of the primary electron beam and can be calculated using the Kanaya-Okayama formula (or other established formulae): several 100 nm to micrometers.
For XRD the information depth depends - besides the energy of the X-rays - on the geometry. It can be reduced using glancing incidence.
The minimum thickness of a metallic coating that can be used to avoid substrate signal interference in X-ray diffraction (XRD) or energy dispersive spectroscopy (EDS) measurements depends on the material being coated and the instrument being used for the analysis. In general, the minimum coating thickness required for XRD analysis is around 10 nanometers, while for EDS, the minimum coating thickness can be as low as 1 nanometer. For a Fe substrate, a MoFe alloy coating of at least 10 nanometers is recommended to avoid substrate signal interference. It is also important to consider the grain size of the coating and the surface
sorry, but to my opinion, all the units 'nanometer', which you mentioned above should be replaced by micrometer...
We and you refer to the minimum coating thickness in order to reduce or even avoid signals from the substrate, unless you operate in grazing incidence in the angular region of x-ray total reflection below and close to the critical angle...