| 摘要 |
<p>Luminophors based on zinc sulphides or zinc:cadmium sulphides are prevented turning grey by the glass coating. The individual crystals of the fluorescent or phosphorescent luminophore are covered with glass which pref. has compsn. by wt. 90-50% SiO2, with 10-50% of B2O3,MgO,CaO,ZnO,Li2O,Na2O, and/or K2O. The pref. coating process consists of mixing the pigment with a soln. (a) of metal alcoholates in alcohol contg. the above glass and possibly also water. Soln. (a) pref. contains 90-50% SiO2, 10-30% B2O3 and/or Al2O3, 0-20% MgO, CaO and/or ZnO, and 0-20% Li2O, Na2O, and/or K2O. The mixt. is converted to a gel by diffusing moisture into the mixt., and the gel is heated to 100-800 degrees, esp. 200-500 degrees C. Used esp. to mfr. fluorescent- or phosphorescent- lacquers or plastics; or ceramic tiles or objects coated with vitreous enamel. Without using the invention, the luminosphors would turn grey with the passage of time.</p> |
