Process for coating a substrate with titanium dioxide

Abstract

A process for coating a substrate surface with titanium dioxide, which process comprises the D.C. plasma sputtering and/or mid-frequency sputtering from a sputtering target which comprises sub-stoichiometric titanium dioxide, TiO x , where x is below 2.

1 . A process for coating a substrate surface with titanium dioxide, which process comprises the D.C. plasma sputtering and/or mid-frequency sputtering from a sputtering target which comprises sub-stoichiometric titanium dioxide, TiO x , where x is below 2 and which has a resistivity of below 1 ohm.cm.  
     
     
         2 . A process as claimed in  claim 1  wherein the sputtering from the target is carried out using as the plasma gas argon, or a mixture or argon and nitrogen, whereby the coating formed on the substrate surface comprises sub-stoichiometric titanium dioxide, TiO x , where x is below 2.  
     
     
         3 . A process as claimed in  claim 1  wherein the sputtering for the target is carried out using as the plasma gas a mixture of argon and oxygen, or a mixture of nitrogen and oxygen, whereby the coating formed on the substrate surface comprises stoichiometric or substantially stoichiometric titanium dioxide.  
     
     
         4 . A process as claimed in  claim 3  wherein the plasma gas comprises 70 to 90% by volume argon and 30 to 10% by volume oxygen.  
     
     
         5 . A process as claimed in any one of  claims 1  to  4  wherein the substrate which is coated is optical glass, the screen of a cathode ray tube, a cold mirror, a low emissivity glass, an architectural glass, an anti-reflective panel glass, the screen of a cathode ray tube, a flexible film or a water vapour and oxygen barrier film.  
     
     
         6 . A process as claimed in any one of the preceding claims wherein the sub-stoichiometric titanium dioxide has a resistivity of less than 0.1 ohm.cm.  
     
     
         7 . A substrate which has been coated by a process as claimed in any one of  claims 1  to  6 .  
     
     
         8 . A substrate as claimed in  claim 7  which is a flexible film coated with sub-stoichiometric titanium dioxide, TiO x , which has anti-static properties.  
     
     
         9 . A substrate as claimed in  claim 7  wherein the coating is sub-stoichiometric titanium dioxide, TiO x , which has a rutile crystalline structure.