Determination of Nickel(II) Oxide in Ceramic Pigments by In Situ X‐ray Diffraction Quantitative Analysis

Abstract

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.

Thermal Behavior of the Raw Materials Forming Porcelain Stoneware Mixtures by Combined Optical andIn SituX‐Ray Dilatometry

“…The peak is hidden at room temperature by the major 200 peak of zircon and becomes evident with increasing temperature, due to the different thermal expansion of the two phases along different crystallographic directions. In situ QPA, using peaks revealed as a consequence of different thermal expansions of two phases, has already been reported in the literature 49 . Hence, the positive variation in the range 550°–600°C is attributed to the α‐ to β‐quartz phase transition.…”

Preparation, Chromatic Properties Analysis and Proportioning Optimization of Co-Cr-Fe-Based Black Pigment

“…The typical commercial black pigments used in the ceramic industry consist of two basic spinels: iron-cobalt-chromite (Fe,Co)(Fe,Cr) 2 O 4 (DCMA 13-40-9) and chrome-iron-nickel (Ni,Fe)(Fe,Cr) 2 O 4 (DCMA 13-50-9) black spinels [9,10]. Due to environmental friendliness and health regulations, Ni is required to be removed from the recipes [11]. Mestre and co-workers [12] reported the synthesis and characterization of the Cr 2 O 3 -CoO-FeO black pigment, which was synthesized using the solution combustion method.…”

Ni-free, black ceramic pigments based on Co—Cr—Fe—Mn spinels: A reappraisal of crystal structure, colour and technological behaviour

“…In order to fulfil the new requirements, important changes have been brought to particle size distribution, by moving towards submicrometric size [41,42], and composition of pigments, e.g. removing Ni from recipes [42,43]. Thus colorant manufacturers have been forced to a big effort to reformulate black pigments by a trialand-error procedure that has turned evident the need of a better understanding of the role of spinel crystal chemistry and the effect of phenomena occurring during firing.…”