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X-Ray Powder Diffraction (XRD)

X-ray diffraction (XRD) is a powerful nondestructive technique for characterizing crystalline materials. It provides information on crystal structure, phase, preferred crystal orientation (texture), and other structural parameters, such as average grain size, crystallinity, strain, and crystal defects. X-ray diffraction peaks are produced by constructive interference of a monochromatic beam of X-rays diffracted at specific angles from each set of lattice planes in a sample. The peak intensities are determined by the distribution of atoms within the lattice. Consequently, the X-ray diffraction pattern is the fingerprint of the periodic atomic arrangements in a given material. A search of the ICDD (International Centre for Diffraction Data) database of X-ray diffraction patterns enables the phase identification of a large variety of crystalline samples.

EAG’s multiple X-ray diffraction systems are equipped with optical modules that can be exchanged, depending on the analysis requirement, without affecting the accuracy of positioning. It is simple to change between line and point focus of the X-ray source, enabling simple switching from a regular XRD configuration to a high-resolution XRD configuration as needed. Different combinations of optical modules enable the analysis of powders, coatings, thin films, slurries, fabricated parts, or epitaxial films.  EAG also has microdiffractometers with 2D area detectors for small spot (<50µm) XRD, providing good signal-to-noise even with small X-ray beam sizes.

Main Applications of XRD Analysis

  • Identification/quantification of crystalline phase
  • Measurement of average crystallite size, strain, or micro-strain effects in bulk materials and thin-film
  • Quantification of preferred orientation (texture) in thin films, multi-layer stacks, and manufactured parts
  • Determination of the ratio of crystalline to amorphous material in bulk materials and thin-films
Ideal Uses
  • Phase identification for a large variety of bulk and thin-film samples
  • Detecting minor crystalline phases (at concentrations greater than ~1%)
  • Determining crystallite size for polycrystalline films and materials
  • Determining percentage of material in crystalline form versus amorphous
  • Measuring sub-milligram loose powder or dried solution samples for phase identification
  • Analyzing films as thin as 50Å for texture and phase behaviors
  • Determining strain and composition in epitaxial thin films
  • Determining surface offcut in single crystal materials
  • Measuring residual stress in bulk metals and ceramics
Technical Specifications

Signal Detected: Diffracted X-rays
Elements Detected: All elements, assuming they are present in a crystalline matrix
Detection Limits: Quantitative multiphase analysis: ~1%
External standard quantitative analysis: ~0.1%
Special quantitative analysis (quartz, polymorphs): ~0.02%
Minimum film thickness for phase identification: ~20Å
Depth Resolution: Sampling depth between ~20Å to ~30µm, depending on material properties and X-ray incidence angle
Imaging/Mapping: None
Lateral Resolution/Probe Size: Point focus: 0.1mm to 0.5mm; Line focus 2mm to 12 mm; Microdiffraction to ~20µm

  • Nondestructive
  • Quantitative measurement of phase and texture orientation
  • Minimal or no sample preparation requirements
  • Ambient conditions for all analysis
  • Cannot identify amorphous materials
  • No depth profile information
  • Minimum spot size of ~20µm