Substrate with photocatalytic coating
The invention concerns a method from cathode spray deposition of a coating with photocatalytic properties comprising titanium oxide at least partly crystallised in anastatic form on a transparent or semi-transparent support substrate, such as glass, vitroceramic, plastic. The substrate is sprayed under a pressure of at least 2 Pa. The invention also concerns the resulting coated substrate, wherein said substrate constitutes the top layer of a series of thin antiglare layers.
1. A process for depositing a coating having photocatalytic properties by sputtering, said coating comprising titanium oxide at least partly crystallized in the anatase form on a transparent or semitransparent carrier substrate of glass, glass-ceramic or plastic, wherein the sputtering is carried out at a deposition pressure P of at least 2 Pa and at ambient temperature, the deposition of the coating being optionally followed by a heat treatment.
2. The process as claimed in claim 1 , wherein the deposition pressure P is from 2.67 to 6.67 Pa.
3. The process as claimed in claim 1 , wherein the process comprises said heat treatment, and wherein the heat treatment is carried out at a temperature of at least 400° C.
4. The process as claimed in claim 1 , wherein the coating has a refractive index greater than 2.
5. The process as claimed in claim 1 , wherein the coating comprises titanium oxide crystallites having a size of less than or equal to 50 nm.
6. The process as claimed in claim 1 , wherein the coating has a RMS roughness of at least 2 nm.
7. The process as claimed in claim 1 , wherein the coating has a geometrical thickness of less than 150 nm.
8. The process as claimed in claim 1 , wherein the sputtering is carried out in a reactive manner from an essentially metallic target, or in a nonreactive manner from a ceramic target.
9. The process as claimed in claim 8 , wherein the target to be sputtered is doped with a metal selected from the group consisting of Nb, Ta, Fe, Bi, Co, Ni, Cu, Ru, Ce, Mo, and Al.
10. The process as claimed in claim 1 , wherein the process is preceded and/or followed by a step of depositing at least one layer by a sputtering technique or by a technique comprising thermal decomposition by pyrolysis or by sol-gel, to increase the roughness of the coating.
11. The process as claimed in claim 10 , wherein the process is preceded by the deposition of at least one layer by pyrolysis or by chemical vapor deposition (CVD), said layer having a RMS roughness of at least 5 nm.