Transparent alumino-boro-phosphate glass coating on a thermally tempered soda-lime silicate glass substrate

Alumino-boro-phosphate (ABP) glass, which is generally used as a porcelain enamel material on a metal surface, was applied on the surface of thermally strengthened soda-lime silicate (SLS) glass. The ABP glass was coated by screen printing and formed using the conventional thermal tempering process for soda-lime glass. The coefficient of thermal expansion (CTE) of the ABP glass was adjusted by compositional change to minimize thermal shock between the coated layer and the SLS glass substrate. The coated ABP glass layer induced haze and decreased the transmittance of the SLS glass. The haze was reduced by controlling the powder size of the ABP glass. However, a significant enhancement in transmittance was achieved with the addition of ZnO nano-powder, achieving transmittance up to 85%. The origin of the haze and the effect of the nano-powder on transmittance were investigated with XRD and SEM/EDS and discussed.