Determination of nickel(II) oxide in ceramic pigments by in situ X-ray diffraction quantitative analysis

Nickel(II) oxide (NiO) still is extensively used as a raw material for the synthesis of traditional ceramic pigments, despite the fact it is potentially carcinogenic. One of the reasons is that, unfortunately, no widely accepted methods exist for its determination in ceramics so far (the main reason being experimental difficulties). Quantitative phase analysis via powder X-ray diffractometry, for example, may fail because of the presence of glass and because NiO diffraction peaks overlap those of spinel in spinel-based pigments. This communication elucidates how to address these experimental difficulties and determine free NiO in the case of black ceramic pigments.