Effective parameters for synthesis of chromium doped YAlO3 red pigment

Abstract

Purpose – The purpose of this article is to evaluate the role of mineralisers on the formation of perovskite structure, optimise the amounts of chromium content, soaking time and finally the ratio of fuel (citric acid) to oxidiser (metal nitrate) and investigation of the physical properties of resulted pigments. Design/methodology/approach – A red pigment based on perovskite structure (YAl1-yCryO3, y = (0.01-0.1) was synthesised by solution combustion method with various mineralisers, like NaF, MgF2 and Li2CO3. Thermal decomposition of the resulting nitrate-citrate gels and the phase evolution of calcined powders were investigated and the microstructure and colorimetry of the emerging products were characterised. Findings – The most effective mineraliser system for the formation of YAlO3 perovskite was NaF:MgF2:Li2CO3 (3:2:1 by weight). Furthermore, desirable pigments were obtained by firing the samples at 1,400°C for 4 hours. The highest redness parameter (a*) and reflectance value were obtained when y was 0.03 and 0.01, respectively. Increasing the fuel: oxidiser ratio led to an increase in the a* parameter. Use of the optimum prepared red pigment in the low and high firing temperature glazes gave a high chemical and thermal stability. Research limitations/implication – Only citric acid was used as fuel. Other fuels and different ratios of fuel to oxidiser could also be studied. Practical implications – The method developed provided a new approach for preparation to nontoxic, high-temperature, ceramic red pigment compared to the solid-state method. Originality/value – The methods for synthesis of pigment based on perovskite structure with different chromium contents and for evaluation of thermal stability of pigment in glaze were novel.