In Search of Ultra-Black Ceramic Pigments Using Microwaves: Delafossite Cuprates CuMO2 (M = Mn, Fe, Cr)
Year: 2025
Type: article
Abstract: Cuprate delafossite phases such as CuMnO2 (crednerite) and CuFeO2, as well as iron- and manganese-doped mcconnellite composites, were investigated as candidates for producing intense black ceramic pigments via conventional solid-state synthesis. Both electric kiln and fast dielectric (microwave) firing methods were employed, with mcconnellite (CuCrO2) used as a reference pigment. Microwave firing led to a marked improvement in sample blackness compared to conventional electric firing. Among the delafossite phases, only mcconnellite subjected to microwave-assisted firing (RVis = 1.40%, corresponding to 98.60% visible light absorption) emerges, pending further optimization, as a promising candidate for an ultra-black ceramic pigment (RVis < 1%) under optimized glaze conditions (ZnO-free) and a firing temperature of 1000 °C. Considering the pigments in powder form, microwave-fired crednerite (RVis = 4.85%, 95.15% absorption) and iron- and iron–manganese-doped mcconnellite composites (RVis = 3.27% and 3.23%, respectively) appear as potential candidates for deep-black pigments (RVis < 3%), benefiting from the composite effect between the delafossite phase and the associated chromium spinel. Moreover, microwave-fired crednerite also demonstrates noteworthy potential for deep-black coloration in glazed samples (RVis = 4.27%, 95.73% absorption).
Source: Materials
DOI: 10.3390/ma18214910
Authors: Guillermo Monrós, Vicente Esteve, Carolina Delgado, Guillem Monrós-Andreu, Mario Llusar
Institution: Universitat Jaume I
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W4415647761