Study the Effect of Chromium Doping Concentration on the Shape and Particle Size of Malayaite Red Nanopigments

In this research chromium doped malayaite (CaSn(1-x)CrxSiO5) was synthesized as a ceramic red pigment by ceramic method at 1250˚C. Four samples of malayaite were synthesized having 0.005, 0.0075, 0.01 and 0.02 molar ratio of chromium and were dispersed in 2-ethyl hexyl stearate by a satellite milling system. The dispersed pigments were printed on the ceramic by silk screen printing method in the industrial situation. The samples were analyzed by XRD, SEM, DRS (Diffuse Reflectance Spectroscopy) and CIE L*a*b* colorimetric system. It was found that change of the amount of chromium concentration from 0.005 to 0.02 in the structure, changes not only the color of the pigment, but also the average particle size and the shape of particles. The shape of the particles changed to rod like particles and the mean diameter of rods was reduced from 500 nm to 150 nm after increasing the concentration of chromium dopant. The printed ceramic were analyzed by SEM and CIE L*a*b* colorimetric system. The mean particle size of the pigments on the printed ceramic was measured less than 100nm.