X-Ray Diffraction (XRD)
X-ray powder diffraction is a technique that uses an X-ray beam to characterize the crystallographic structure of natural and synthetic materials. When crystalline materials are irradiated, a certain portion of the X-ray beams will be scattered by the material’s crystal structure generating a characteristic pattern (diffractogram), unique to each compound.
The identification procedure is performed by matching the pattern against a database (ICDD), which contains 1 047 661 unique data sets of inorganic and organic substances.
In addition to pure substances, X-ray diffraction can also be used to characterize mixtures and to determine the ratio of crystalline vs non-crystalline materials in a sample.
Analyzes different types of samples and monitoring phase transitions
Our instrument is equipped with a range of different sample holders that allows us to analyze different types of samples: from powders to fragments, films and microsamples.
Standard powder samples can be measured in reflection and transmission modes. Small samples can be measured mounted on a spinning glass capillary, while larger objects can be placed on the adjustable x-y-z stage.
Additionally, a heating chamber, with a temperature range up to 1200⁰ C, and a climate chamber (up to 300⁰ C) allows to monitor phase transitions under varying relative humidity (RH) and temperature conditions.
Uses of the X-ray diffraction technique
The technique has been put to a number of uses in the cultural heritage field such as:
- Analysis of metal corrosion
- Gemstone decoration on jewellery
- Pigments on wall paintings
- Ceramics
- Opacifiers in glass
- Salt growth on objects
- Conservation materials and minerals
In addition to the traditional application to inorganic materials, X-ray diffraction can also be employed to study some organic compounds characterized by partially crystalline structures (e.g. some cellulosic and proteinaceous materials).
