Metallograhy
Metallography is the study of the physical structure and components of metals,
typically using microscopy. Ceramic and polymeric materials may also be prepared
using metallographic techniques, hence the terms ceramography, plastography and
collectively materialography.
The mechanical properties of the materials are strongly affected by their microstructures.
Metallography is one of the most used methods in metallurgy in order to characterise
the microstructures of the materials.
This method allows the study and characterisation of metals, ceramics and polymers.
Optical and electronic microscopy are the major techniques used to obtain images
of the characteristic microstructures of the materials.
Optical microstructure analysis is an essential step in determining the cause of
failure due to manufacturing process irregularities. Since metals and most non-metallic
materials contain a specific crystal structure directly connected to or created
by a manufacturing process, optical examination of this crystal structure provides
insight to processing irregularities.
Metallography Method
The process is mainly done according to the following sequences:
Sample cutting, cleaning, mounting, grinding by using SiC papers, polishing by using
diamond paste, alumina paste, magnesium oxide, colloidal silica, acid etching (HNO3,
HCl, HF, etc), acquisition of the microstructure’s image by using optical and/or
electronic microscopy and using image analysing system to quantify different phases
of microstructure.
