Patent ID: 7527868

Claim:
A transparent glass substrate ( 1 , 1 ′, 1 ″) coated with one or more thin layers ( 6 , 16 , 28 ) wherein the thin layer most distant from the glass substrate is a composition comprising silicon nitride, carbonitride, oxynitride or oxycarbonitride, said thin layer most distant from the glass substrate being covered by a second layer ( 7 , 17 ) which protects against high-temperature corrosion, wherein the second layer comprises one of the following: (a) a mixture of Ti and at least one metal other than Ti whose oxide is capable of blocking or absorbing corrosive species comprising Na 2 O at high temperature; and (b) a metal or metal oxide which is substoichiometric in terms of oxygen, wherein the second layer comprising (a), if present, has a thickness of 2-20 nm and the second layer comprising (b), if present, has a thickness of 1-10 nm.