**2.3 Microstructural characterization**

This section focuses on all characterization techniques of ECAPed magnesium alloys including all forms of microscopy and analysis especially microanalysis and surface analytical techniques. The methodology of microstructure analysis and phase identification are also discussed.

*Effect of ECAE Die Angle on Microstructure Mechanical Properties and Corrosion Behavior… DOI: http://dx.doi.org/10.5772/intechopen.94150*

## *2.3.1 Optical microscope*

Specimens for microstructure inspection were prepared by mechanical polishing with silicon carbide abrasive papers (grades of 400, 800, 1000, 1200, 1500, 2000) followed by cloth polishing using diamond paste and kerosene for obtaining mirror finish surface and finally cleaned with acetone. Further, Etching was carried on the polished surface for approximately 3 to 5 s, in a solution of 4.2 g picric acid, 10 ml acetic acid, 10 ml distilled water and 70 ml ethanol for 3–5 s [8–12]. So that sample turns light brown and washed with running distilled water and dried. Microstructures and elements distributions were observed and analyzed using optical microscopy by image analyzer facilitated BIOVIS material plus software, and average grain sizes were measured by linear intercepts method according to ASTM E-112. Same samples were observed under a scanning electron microscope.
