Metallographic replicas allow on-site (in-situ) and non-destructive surface examination.
This is very useful when you cannot move and destroy the object to be examined, such as a metal bridge, a tank, etc.
Polishing the surface to be examined (such as a weld, a trace of corrosion, etc.) will be accomplished with a portable polishing machine using self-adhesive discs, usually Ø32mm (abrasive papers from P60 to P1200, polishing cloths with diamond pastes 6, 3 and 1µ + polishing lubricant). If necessary, a metallographic etching depending on the nature of the material will be carried out, chemically only with a conventional etching reagent, or using an electrolytic etching with an electrolytic polishing machine.
Thanks to the XREP-type cellulose acetate film marketed by NX-MET, a particularly faithful replica can thus be examined in the laboratory under a metallurgical microscope. NX-MET
offers these films in 35µ (the most common) but also in 125µ and 180µ for more specific applications.
The cellulose acetate film allows surfaces to be replicated with extreme precision on the order of a micron. There are also pastes based on silicone and hardener, but the definition of the reproduction is much less precise.
The implementation of replicas with acetate film is relatively simple :
1: Wet the surface to be checked with XREP liquid
2: Apply the XREP acetate film on the surface
(we will have previously cut the film to the right size)
3: Remove the film after drying for 2-3 minutes
4: Stick the film on a glass slide
There are small portable microscopes but less easy to use than a laboratory microscope. However, a digital camera can be added to them.
For mechanical polishing, NX-MET markets the Electer EVO, to be connected to the mains (230Vmono) and equipped with micromotors allowing very high rotation speeds and easy handling. Also
available is a portable battery-operated polishing machine, which is particularly easy and simple to use.
Metallographic replicas therefore allow the examination of surfaces. There are also dimensional replicas (metrology) using resins or silicone pastes.