Color stability of blue aluminates obtained from recycling and applied as pigments

Abstract

Aluminates have been used as synthetic inorganic pigments due to their structural stability.

Mixed oxides with corundum-type structure obtained from recycling can seals as paint pigments: color stability

“…It indicates that commercial white paint without added pigments exhibits a more significant color variation (Δ E ) in an acid environment. A work under similar conditions of harsh environments with cobalt and nickel aluminates obtained by the same synthetic route used in this article yielded similar results of color stability [ 14 ], with differences varying between weak and very weak. It is possible that the choice of the synthetic route influences the color stability since formation and stability of the structure affect this parameter.…”

“…In the first step, 50 mL of water was added to 10 wt % (in relation to the total mass of boehmite powder (w/w)) of transition metal chloride (CrCl 3 or FeCl 3 ) powder (5 and 20 wt % amounts were also prepared, see Supporting Information File 1 ). Then, 3 g of boehmite was added and left under constant stirring (600 rpm) for 24 h. Next, this mixture was calcined at 1000 °C, macerated, and stored [ 14 ] ( Figure 9 ). The obtained products were labeled “sample 1” for boehmite with chromium atoms and “sample 2” for boehmite with iron atoms.…”

“…The plaster blocks were placed in the desiccators, which were then sealed. Colorimetric measurements were performed before the test and after 120 and 240 h to determine the colorimetric stability of the aluminates applied as synthetic inorganic pigments [ 14 ].…”

“…Chromium oxide green belongs to the class of inorganic green and blue-green pigments [ 14 ]. It exhibits the corundum structure and a color change with increasing particle size from brighter yellow-green to darker blue-green [ 14 ].…”

“…Chromium oxide green belongs to the class of inorganic green and blue-green pigments [ 14 ]. It exhibits the corundum structure and a color change with increasing particle size from brighter yellow-green to darker blue-green [ 14 ]. Usually, chromium oxide pigments are synthesized starting from dichromats with chromium in the oxidation state +6, which are toxic [ 15 ].…”