Q:
Why is understanding sample preparation
important . . . do I have to have a met lab . . . Where
can I find color etching metallography examples?





A:
  • It is important to understand metallographic sample
    preparation in order to preserve important features
    and not destroy/alter any that may be needed later.

  • Large suppliers, and many smaller niche suppliers,
    of met lab equipment and materials will provide training
    and advice on sample preparation, including:
    - Buehler, Lake Bluff, IL
    - Leco, St. Joseph, MI
    - Struers, Westlake, OH

  • If an inhouse "met lab" is unavailable, many labs can
    do this. If a lab is used, it is very important to describe
    specifically what you want from the specimen.

  • Mount, polish, etch procedures can get very specific,
    depending on specimen material -- metal (hard/soft),
    ceramic composite -- and information desired.

  • Etching reveals features by improving contrast, showing
    different height differences, and sometimes staining and/or
    coloring different phases.

  • "Relief polishing" using 0.1 micron alumina or
    diamond can eliminate need for etching.

  • Sample preparation procedures must be considered along
    with viewing procedures - AFM, SEM, visible light, etc.
    Excellent references are available, including:

    - "The Metalog Guide," L. Bjerregaard, et al,
    pub. by Struers, 1992,revised 1996, ISBN 87-982864-2-0.

    - "Metallographic Etching," G. Petzow,
    pub. American Society for Metals, 1978, ISBN 0-87170-002-6.

    - "Metallographic Polishing by Mechanical Methods, 3rd Ed."
    L. E. Samuels, American Society for Metals,ISBN 0-87170-135-9.

Illustrated examples of Polish/Etch and copper color metallography
of importance are available in our Technical Photo Gallery.