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

Analytical Science Group
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XRay Diffraction
Powder Diffraction
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X-Ray Diffraction
Powder Diffraction
In x-ray diffraction, powder method refers to analysis of specimens consisting of many crystallites. This can either be true powders (e.g. baby powder) or polycrystalline solids.

Technicians process a sample using x-ray powder diffraction method
 
Above: Technicians process a sample using x-ray powder diffraction method.
 

Capabilities
  • Phase Identification - qualitative, semi-quantitative (Relative Intensity Ratio Method) and quantitative (Rietveld method)
  • Lattice parameter measurement
  • Crystal size and microstrain measurement
  • Residual stress
  • Texture analysis (pole figures and orientation distribution function)
  • Please refer to the examples listed on the right of this page

Instrumentation
Bruker D8 Discover with GADDS Area Detector
  • State-of-the-art area detector with real-time display
  • Point focus with microdiffraction capability down to 150 microns
  • Videomicroscope/laser alignment system
  • Centric Eulerian one-quarter cradle, 360 degree phi stage, x-y-z stages, all motorized and computer controlled
  • Reflection or transmission geometry
  • Hot stage for data acquisition in high vacuum, air or argon up to 1100C
  • Sample sizes up to 40mm x 80mm x 80mm (25mm diameter and 3mm thick for hot stage)
  • Automated data acquisition
  • Cu>Mn and Cr x-ray sources

Phillips APD3600 Automatic Powder Diffractometer
  • Focusing geometry (Bragg-Brentano)
  • Sample sizes up to 140mm x 140 mm x 140mm
  • Automated data acquisition
  • Cu x-ray source
Close-up of D8 Discover w/GADDS x-ray Diffractometer
 
Above: Close-up of D8 Discover w/GADDS x-ray Diffractometer.
 

Examples
For further information please contact Rick Rogers
Examples
Phase ID - Example 1
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Phase ID - Example 2
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Texture Example
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Last Updated: May 13, 2008