Process for the deposition of precious metals on glass and on vitrified ceramics, and products obtained by this process

Claim 1

A PROCESS FOR THE METALLIZATION OF A GLASS OF VITRIFIED CERAMIC OBJECT COMPRISING FIXING ON SAID OBJECTS AN INTERMEDIATE COLLOIDAL HYDRATE OF A METAL OTHER THAN AN ALKALINE EARTH METAL AND A COLLOIDAL DISPERSION OF A NOBLE METAL TO FORM AN INTERMEDIATE FILM ON SAID OBJECT, AND EXPOSING SAID FILMED OBJECT TO A FINAL METALLIZING BATH INCLUDING LESS THAN ABOUT 0.1% BY WEIGHT OF A SALT OF A PRECIOUS METAL SELECTED FROM THE GROUP CONSISTING OF GOLD, PLATINUM, RHODIUM, IRIDIUM, OSMIUM, PALLADIUM, RUTHENIUM AND MIXTURES THEREOF AND A REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF PEROXIDES AND HYDRAZONIUM DERIVATIVES, SAID AGENT CAPABLE OF REDUCING SAID SALT TO SAID PRECIOUS METAL ONLY ON CONTACT WITH SAID FILM WHEREBY SAID OBJECT IS METALLIZED WITH SAID PRECIOUS METAL WITHOUT FORMATION OF REDUCED PRECIOUS METAL OTHER THAN ON THE SURFACE OF SAID OBJECT.