Methods

X-ray Diffraction (XRD)

A Siemens D5000 Diffractometer with Bragg-Brentano geometry could be employed for XRD at the Technische Universität Wien, Institute of Applied Physics (Prof. Dr. M. Mantler). It was equipped with a θ-θ goniometer (401 mm in diameter), a copper (Cu)-tube with line-focus and a scintillation detector. The diffractograms were measured in an angle of 5° to 80° (2θ) with a measurement time of 10 seconds per step (increment 0.02°); the tube power was 40 kV with 40 mA. For suppressing the Kβ-reflexes a Ni-filter (thickness of 12 μm) was mounted after the collimator. As a result the Kα-lines were reduced too.

The powdered samples were applied on a sample holder made of glass, covering an area of 25x25 mm² with a sample depth of about 1 mm. The evaluation of the diffractograms was done by using the "Evaluation Program EVA" (Bruker AXS GmbH, 1997) and comparing it with the commercial database of the International Centre for Diffraction Data (ICDD, 2002)¹.

Siemens D5000 Diffractometer of Bruker AXS GmbH is shown on the left, and sample holder made of glass, covered with the pigment powder on the right.