New glass-based coatings coloured with red pigments for Foamglas® panels

This work describes the design and development of new coloured glass-based coatings for Foamglas® substrates. Four kinds of pigments were added in different proportions (1 and 5 wt% respectively) to a borate glassy matrix (labelled as G7) by two different mixing techniques; the chosen pigments were goethite (α-FeOOH), acicular hematite (Fe2O3) spherical hematite and TiO2 coated hematite. No interaction occurred between the selected pigments and the G7 matrix and consequently no new phases were formed in the reported experimental conditions. Coatings on the Foamglas® substrates were sintered at 560 °C for 1 h and showed different porosity, pigment dispersion in the matrix and colour development, depending on the mixing technique.The porosity was exploited to add TiO2 coated hematite into the coating, for photo-catalytic purposes. Each coating was deposited without affecting the Foamglas® substrate porous structure.