Synthesis and Characterization of Orange Pigments from Rare Earth Metal Ions

Abstract

New inorganic pigments were synthesized through calcination route with advantages such as the ability to prepare homogeneous oxides of lower size, which could provide for higher surface coverage. The synthesized inorganic pigments were characterized by various techniques like infrared, UV-visible spectroscopy and diffuse reflectance spectroscopy (DRS) using CIE -L*a*b* parameters method for colour measurements. The above characterized inorganic pigments were used for the study of the pigments of associated ions. Solid state reactions of these metal ions with transition metal ions like chromium, molybdenum, manganese and iron were carried out individually. A replacement for cadmium, cobalt, lead and mercury based pigments has been sought through the use of rare earth metal ions -cerium and lanthanum. It was found that cerium offered better scope for doping than lanthanum as it produced better shades. Multiple doping plays a vital role in increasing the mass tone and tint strength.

Novel Orange Color Pigments Based on La3LiMnO7

“…Although the bayferrox orange pigment is environmentally friendly, the vividness of this pigment is not sufficient. Therefore, development of environmentally friendly inorganic orange pigments is required, and several studies have been reported [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. Some compounds, such as La 2 Ce 2− x W 0.5 x Fe 0.5 x O 7+ δ [ 14 ], Sr 4 Mn 2 Cu 0.5 Zn 0.5 O 9 [ 15 ], and SrBaCe 0.6 Tb 0.4 O 4 [ 3 ], for example, have been proposed and exhibit an orange color.…”

Synthesis and Color Evaluation of Ta5+-Doped Bi2O3

“…However, application of these orange pigments containing toxic elements, such as Cd, Pb, Cr, has been forbidden or restricted, because they have harmful effects on the human body and the environment. Therefore, development of inorganic orange pigments without toxic elements is required and several studies have been reported. − …”