Sublimate residue of ammonium chloride (9 wt%) mixed with pyrrhotite sub-micrometer sized grains at 173 K inside the sample holder (48 mm in diameter and 5 mm deep) in the CARBONIR simulation chamber.

Zoom on a fragment of the sublimate residue of ammonium chloride (9 wt%) mixed with pyrrhotite grains measured by Scanning Electron Microscopy outside the simulation chamber on 05/10/2018. The sub-micrometric to micrometric pyrrhotite grains are arranged in a porous structure as a result of the freezing and sublimation processes. The ammonium salt is possibly the causing the veil-like structures seen on this image between the pyrrhotite grains.