This document describes methods for the determination of mineralogical phases often present as additives or reaction products in carbon containing or graphitic refractory products by X-ray Diffraction (XRD) using a Bragg-Brentano diffractometer. It includes details of sample preparation and general principles for qualitative and quantitative analysis of mineralogical phase composition. Quantitative determination of α-Si3N4, β-Si3N4, AlN, aluminium metal, Al4C3, silicon metal, boron carbide and BN are described. The problems encountered with some determinations are highlighted.
Additional reduced species present in some refractories could include Al2O3⋅AlN solid solutions (so called Alons), Si3N4⋅SiO2 solid solutions and Si3N4⋅Al2O3 solid solutions (Sialons). The presence of some of these solid solution components will cause problems with both identification and quantification as they are not well-defined structures.
NOTE For rationalisation of nitrogen containing phases, the total nitrogen content, analysed in accordance with EN 12698-1 is used.