Qualitative Compound Analysis
General XRD - Qualitative Compound Analysis
AMIA Laboratories specializes in X-ray analysis to qualitatively determine which compound(s) are present in a sample. Many times this is coupled with x-ray fluorescence(XRF) in order to determine both the elements present and the compounds formed from these elements. Qualitative XRD can help identify 50 micron surface impuraties to phases in cement. In adition AMIA Labs offers XRD mapping in order to probe the spacial distribution of crystallographic phases from a unique feature.
General XRD: Qualitative Analysis
General x-ray diffraction phase (compound) identification will report the major, minor, and trace materials present in a sample. The data usually includes the mineral (common) name of the substance, type of phase, chemical formula, crystalline system, and reference pattern number from the ICDD database. Micro-XRD can be done on very small samples, such as hairs or fibers for forensics, or small areas of larger samples, such as deposits on pipes. Not all compounds are the ICDD data base so comparisions between one sample and a reference may be necessary( e.g. hairs, fibers, and alloys).
Qualitative Analysis (phase/composition)
X-ray diffraction for phase (compound) identification will report the major, minor, and trace materials present in a sample. The pattern measured is compared to know patterns from the International center for diffraction data (ICDD) in order to determine if a compound is present. The data obtained from a matched pattern usually includes the mineral name of the substance( if appropriate), chemical formula, crystalline system, and reference pattern number. Micro-XRD can be done on very small samples, 50 microns or small areas of larger samples, such as deposits on pipes.
Qualitative Analysis : Comparative Analysis
Many XRD patterns are not in the ICDD database so they cannot be identified unless a know reference sample is used. This qualitative work involes 2 data collections; (1) the refernce sample is collected and catalogued; and (2) the unknown is collected. The pattern can then be put intoa company specific data base for future reference in order that in can be compared to any company specific sample in the future. Usually the comparision is between standard 1D diffraction patterns but 2D diffraction patterns can also be compared. This is usually performed to compare oriented materials such as fibers and films. Recently nanotubes have been compared using oriented patterns.
Related XRF Services
XRF is a complement to XRD in that it provides a list of elemts present in a sample. In addition, if a quantitative XRF analysis is performed, it can be used in detmining if one compound or an isostructural one is the proper crystallographic phase. A sample can have amorphous materials that do not show up as unique diffraction patterns. XRF analysis can identify the elements present in this amorphous material. The lists below will help
X-ray diffraction (XRD) analysis can provide:
- Compound composition
- Texture, crystal orientation
- Residual stress, strain
- Percent crystallinity
- Grain (crystallite) size
- Film thickness, density
- Crystal structure
X-ray fluorescence (XRF) can provide support for XRD analysis:
- Qualitative or Quantitative elemental analysis of solids
Sample types include:
- Thin films, coatings
- Polymer sheets, fibers
- Metals, ceramics, composites
- Ribbons, wires, tapes
- Single-crystal, polycrystalline, amorphous materials
- Powders, bulk solids
- Fabricated parts
Application Notes are available on the following General topics:
- Application Note C02: Crystallite Size and Microstrain Analysis of Pyrolic Carbon or Graphite Structures
- Application Note G01: General XRD Phase/Composition Identification
- Application Note G02: Texture/Orientation Distribution Function (ODF) of Rolled Aluminum
- Application Note G03: Semi-Quantitative Analysis - using the RIR method
- Application Note M01: Microdiffraction
- Application Note M02: X-ray Microdiffraction for Residual Stress Determination
- Application Note Q04: Forensic Analysis by X-ray Diffraction
- Application Note R01: Rietveld Analysis using RIQAS
- Application Note T04: Texture or Crystallite Orientation
