Metallography
Metallography is the study of the physical structure and components of metals, typically using microscopy and other analytical techniques. Ceramics and polymeric materials may also be prepared using metallographic techniques, hence the terms ceramography, plastography and collectively, materialography.
We have in house capability and expertise of sectioning, mounting and polishing of a variety of samples and material types. This technique is routinely used to analyse materials for the Aerospace industry, electronics industry, petrochem and marine industry among others.
A large number of material properties can be revealed through mounting and polishing. With careful sectioning, phenomenon below the surface become obvious, and an understanding of the material’s micro and macrostructure can be quickly gained:
- Phases can be identified.
- Crystal size can be measured, and from that an estimation can be made as to the level of heat treatment the material has received.
- Voids and particulate inclusions can be observed.
- Macro cracks can be measured and the depth recorded. Micro cracking along the surface or within the structure can be used to infer levels of stress experienced by the sample.
- Paint thicknesses can also be measured by this technique and then subject to further analysis for compositional information.
- Hot and Cold Mounting
- In house sectioning & polishing
- Progressive analysis of features and faults
- Digital images of all sections
- Measurement of features and faults
Methodology
The process involves a number of steps. Initially, samples must be of an appropriate size before they can be mounted. This generally involves careful consideration, ensuring that the features of interest will be observable and not destroyed by the polishing process. The samples are then arranged and either hot or cold mounted. Hot mounting involves a clear resin under heat and pressure. For materials which are thermally sensitive, a cold curing mounting resin can be used.
Once mounted, the features of interest must be exposed and polished. Excess material is ground away, and then successively finer grades of glass paper are used to polish the metal surface. A final polish using a colloidal silica suspension or diamond suspension provides an almost mirror like finish. On this page you will find a few examples of features highlighted using these metallographic techniques.
Subsequent to the polishing processes it is possible to apply a range of etching techniques using proprietary formulations to develop surface features and morphology.
Once samples have been prepared to this level additional analysis can be performed using techniques like SEM. However, many materials have a limited shelf life in this state and hence analysis must be conducted quickly in order to obtain the relevant data.
We offer:
Our techniques can be used on most metals, plastics, rubbers, glasses and ceramics.