Q:
What are the advantages and disadvantages
of Chemical Analysis?





A:
  • Gross Chemistry:
    Easiest, fastest approach is the EDAX capability, usually
    purchased with SEM. Also available are visible light
    microscopes with simultaneous FTIR analysis.

    Advantages of Both Systems

  • Fast, can do it while looking at the morphology
    of the sample and possible phases present.
  • Relate composition to location and phases in the
    sample without polishing, e.g., Fracture Surface Analysis


    Disadvantages

  • Must be considered semi-quantitative.

  • Lowest element detected is usually sodium
    but not oxygen.

  • Light element attachments get down to boron.

  • Precision drops with atomic weight. Lowest
    elements are qualitative - in the +/- 10 to 20%
    range, depending on matrix.

  • Detection limits rise as atomic weight decreases.

  • Comparison with standards helps increase the
    precision but requires more time.

  • Can then go to expensive surface science labs to
    do wave length dispersion analysis, SIMS, ESCA, AES, etc.
    Sample preparation and turn around time can be problems.

  • The FTIR attachment available on some of the optical
    microscopes is also a possibility.