X-ray powder diffraction quantitative analysis performedin situat high temperature: application to the determination of NiO in ceramic pigments

Abstract

Although nickel(II) oxide (NiO) is a potential carcinogenic agent, it is still used in the synthesis of ceramic pigments because during their preparation at high temperature, NiO is thought to combine with other compounds, crystallizing as new phases with spinel-like structures. Unfortunately, there are no widely accepted methods for the determination offreeNiO in ceramics, the main reason being experimental difficulties. In fact, quantitative phase analysis (QPA) by X-ray powder diffraction (XRPD) may fail because diffraction peaks of NiO with space groupFm3¯manda≃ 4.18 Å overlap with those of the spinel with space groupFd3¯manda≃ 8.4 Å. To overcome this problem, in this work QPA has been performedin situat high temperature to resolve the peak overlap of NiO and spinel by taking advantage of the different thermal expansion of each phase. It is believed that this is the first report of the application of this technique.