XRF: Short for X-ray fluorescence. Can analyse any element heavier than carbon. The principle: The sample is irradiated by strong x-ray radiation, typically between one and four kW. The sample absorbs the radiation and transmits its own secondary x-ray radiation which is measured, with different settings for each element. The level of radiation corresponds to the element contained in the sample. The sample surface must be totally flat.
XRD: X-ray diffraction. This is used for analysing crystals and chemical compounds. In combination with XRF this analysis provides complete information about the compounds and elements in the sample.
OES: Optical emission. Can measure all elements pre-defined by detectors available. The principle: We submit a high voltage between the sample and an electrode. A discharge, similar to that at welding, occurs. The light appearing is measured and its intensity corresponds to the element in the sample.
Combustion analyses: ”Leco analyses”. Can measure carbon, sulphur, nitrogen, oxygen and hydrogen. The sample is burnt in high temperature; for carbon and sulphur in an oxygen atmosphere and for nitrogen, oxygen and hydrogen in an inert atmosphere, usually helium, nitrogen or argon. When burning carbon and sulphur carbon dioxide and sulphur dioxide is formed and measured by infra red cells (IR-cells).
Oxygen reacts with the crucible, which is carbon, forming carbon monoxide/carbon dioxide, which is measured. Nitrogen and hydrogen are measured as atoms or formed water (H) by thermo-conductive detector or IR-cells.
Qualitative analyses: Defining all elements heavier than carbon by XRF through scanning and calculating the level of each observed element. Time: appr. 15 minutes per sample.
Sample preparation: If the size of the sample is not adapted to the instruments it is prepared through cutting, re-melting, grinding, milling, splitting etc.
