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Structures and Materials Division Research and Technology Directorate NASA Glenn Research Center

Analytical Science Group
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Analytical Chemistry
Electron Optics
Metallography
Optical Lab
Sample Preparation
XRay Diffraction
Gallery
Metallography Lab
Sample Preparation: Mounting
Mounting is the critical first step in any preparation process. The goal is to retain the true structure of the sample. To obtain this goal a variety of mounting techniques are employed in the MetLab. For example bakelite is typically used for general metallic samples, whereas fragile samples require vacuum infiltration with epoxy before sectioning and polishing..

Variety of prepared samples
 
Above: Bakelite hot press (top right), vacuum infiltration (top left), high-pressure infiltration/cure (bottom left), and sample ready for polishing (bottom right).
 

Vacuum infiltration and high-pressure sample preparation
 
Above: Vacuum infiltration of epoxy by first pulling a vacuum on the sample then introducing the epoxy while the sample is under vacuum (left). After vacuum infiltration sample cups are placed in a pressure chamber and put under 1000 psi pressure for approximately 8 hours until the epoxy is cured (right).
 

Mounting Techniques
Bakelite Resin
  • Used mainly for metallic samples where cracking or coatings are not an issue
  • Mounted at 170 degrees C at 30kN of pressure

Two Part Cold Mount Epoxy

  • Epoxy contains a fluorescent dye providing observation of pre-existing cracks and open porosity
  • Critical samples are vacuum infiltrated and high pressure cured at 1000 psi to remove voids and to fill the smallest cracks

Return to sample preparation page...

Examples
For further information please contact Joy Buehler
Capabilities
Mounted samples in the Met Lab
Cutting
Polishing samples in the Met Lab
Polishing
Plasma etched sample in the Met Lab
Plasma Etching
Ceramic composite after intereference layering
Interference Layering


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Last Updated: May 13, 2008