Optical Microscopy of Meteoritic Metal

TECHNIQUES- Etching Sample Selection | Sectioning | Epoxy Mounting | Grinding & Polishing | Etching | Microscopy The metal microstructures can be revealed using Nital (2 volume % HNO3, balance ethanol), the standard etchant for Fe-Ni alloys. Nital preferentially reacts with kamacite (low-Ni) relative to taenite (high Ni), and it also enhances kamacite and taenite grain boudaries. Optimal etching times typically range from 30 to 60 seconds. The etched specimen is washed with ethanol and dried using a hair dryer. It is important to note that Nital will release hydogen gas over time and can become explosive. Therefore, it is recommended that this etchant be prepared and stored in small quantities.