SUBSTRATES THINLY COATED WITH PLATINUM OXIDE, DEVICES FOR OBTAINING THE SO COATED SUBSTRATES AND PRODUCTS OBTAINED FROM SUBSTRATES SO COATED

摘要

To coat a substrate with a thin layer of pure platinum oxide, an insulating and transparent substance, recourse is had to a cylindrical magnetron comprising means for generating an axial magnetic field in an enclosure containing rarefied oxygen, an axial cathode at least coated with platinum and a cylindrical grid forming an anode and coaxially surrounding the cathode so as to reserve an annular zone outside the grid. The substrate is placed in the said zone so that its surface to be coated by the thin layer is shielded from the impact of electrons. This shielding can be obtained by a particular shape given to the bars constituting the grid or by the positioning of obstacles in the said zone. It then suffices to heat the thin layer, whether or not locally, to above 250 DEG C., to convert it into conducting and opaque platinum.