Effect of CeO2, Sb2O3 and As2O3 on the color, transparency and hardness of TiO2: nucleated ZnO-Al2O3-SiO2 glass-ceramics.
ACOSTA, María Helena Ramírez; RODRIGUES, Lorena Raphael; SANTOS, Gisele Guimarães dos; SERBENA, Francisco Carlos; SANTANA, Geovana Lira; MASTELARO, Valmor Roberto; NASCIMENTO, Otaciro Rangel; KOIKE, Akio; YOSHIDA, Satoshi; ZANOTTO, Edgar Dutra.
ACOSTA, María Helena Ramírez; RODRIGUES, Lorena Raphael; SANTOS, Gisele Guimarães dos; SERBENA, Francisco Carlos; SANTANA, Geovana Lira; MASTELARO, Valmor Roberto; NASCIMENTO, Otaciro Rangel; KOIKE, Akio; YOSHIDA, Satoshi; ZANOTTO, Edgar Dutra.
Abstract: Hard and transparent glass-ceramics (GCs) from the ZnO-Al2O3-SiO2 (ZAS) system containing TiO2 as a nucleating agent often exhibit a grayish to brownish hue, limiting their use in applications requiring high-transmittance and colorless materials. This coloration arises from charge-transfer mechanisms involving Ti ions. To address this issue, the oxidizing agents CeO2, Sb2O3, and As2O3 were incorporated individually into a TiO2-nucleated ZAS base composition to promote the oxidation of Ti3+ ions to Ti4+ ions, as the latter exhibits minimal coloring effects. The experimental characterization of the glasses and GCs comprised the following steps: Differential Scanning Calorimetry, to study the influence of the optical clarifiers on the thermal behavior and crystallization kinetics; UV-Vis Spectroscopy and CIELAB color analysis to evaluate the effectiveness of the oxidizers in mitigating the color; Electron Paramagnetic Resonance to determine the oxidation states of the coloring ions; Rietveld analyses to assess the impact of microstructural factors on light absorption; and Vickers microhardness to evaluate the effect of the composition and heat treatments on the mechanical performance. The results demonstrate that As2O3 and Sb2O3 are more effective than CeO2 in reducing coloration and enhancing the transmittance in the visible range of the ZAS GCs containing TiO2 without affecting their hardness.
@article={003299926,author = {ACOSTA, María Helena Ramírez; RODRIGUES, Lorena Raphael; SANTOS, Gisele Guimarães dos; SERBENA, Francisco Carlos; SANTANA, Geovana Lira; MASTELARO, Valmor Roberto; NASCIMENTO, Otaciro Rangel; KOIKE, Akio; YOSHIDA, Satoshi; ZANOTTO, Edgar Dutra.},title={Effect of CeO2, Sb2O3 and As2O3 on the color, transparency and hardness of TiO2: nucleated ZnO-Al2O3-SiO2 glass-ceramics},journal={Ceramics International},note={v. 52, n. 12, Part A, p. 18289-18300},year={2026}}