Investigating red ceramic pigments: Tailoring clay‐iron oxide composites and analyzing the physical characteristics

Abstract This study presents a method for synthesizing red ceramic pigments using nano clay and iron chloride through coprecipitation followed by calcination. Optimal pigment formation was achieved at 1000°C with 4 g of clay, resulting in vivid red pigments with high thermal stability. Characterization techniques—including x‐ray diffraction (XRD), Rietveld refinement, scanning electron microscopy, thermal analysis (thermogravimetric analysis, differential scanning calorimetry), diffuse reflectance spectroscopy, and colorimetric analysis—were employed to identify the factors influencing color intensity. XRD confirmed hematite as the primary chromophore phase, whereas silicon dioxide was found to enhance luminosity. Thermal analysis indicated stability above 860°C with minimal weight loss, demonstrating pigment resilience. Phase transformations at 1000°C produced well‐dispersed hematite nanoparticles within the clay matrix, further intensifying the red color. Colorimetric analysis revealed that increased clay content amplified red color intensity via enhanced light scattering. Calcination at higher temperatures preserved pigment stability, although minor color shifts occurred due to the formation of SiO 2 ‐cristobalite and Al 2 SiO 2 phases. This study provides a practical method for producing stable, tunable red ceramic pigments, suitable for applications in ceramics, paints, and coatings.