ChemInform Abstract: Cataphoretic Deposition of Phosphor.
Abstract
Various phosphors including sulfides, silicates, and rare earth metal based materials (emphasis on ZnS:Ag) are deposited from cataphoretic coating baths containing phosphor particles, Mg(NO3)2·6 H2O, La(NO3)3·6 H2O, and glycerol in isopropanol and the deposits are characterized by ESCA, TGA, FTIR, and AAS.
ChemInform Abstract
Various phosphors including sulfides, silicates, and rare earth metal based materials (emphasis on ZnS:Ag) are deposited from cataphoretic coating baths containing phosphor particles, Mg(NO3)2·6 H2O, La(NO3)3·6 H2O, and glycerol in isopropanol and the deposits are characterized by ESCA, TGA, FTIR, and AAS. It is found that Mg2+ and La3+ near the cathode react to form an adhesive hydroxide matrix which binds the phosphor particles to the substrate. The degree of dissociation of Mg(NO3)2·6 H2O and La(NO3)3·6 H2O in iPrOH is only 1% and 0.1%, respectively. Zeta potential measurements show that the ZnS:Ag phosphor is negatively charged in pure iPrOH and that only an extremely small amount of cations is required to charge the particles positively. The zeta potential data are used to determine the electrophoretic velocity and to develop a model for the deposition rate of the phosphor.
