Barrier layer to SiOC alkali metals
The invention relates to a glazing comprising a transparent glass substrate containing ions of at least one alkali metal and a transparent layer made of silicon oxycarbide (SiO x C y ) having a total thickness E with (a) a carbon-rich deep zone, extending from a depth P 3 to a depth P 4 , where the C/Si atomic ratio is greater than or equal to 0.5, and (b) a carbon-poor surface zone, extending from a depth P 1 to a depth P 2 , where the C/Si atomic ratio is less than or equal to 0.4, with P 1 <P 2 <P 3 <P 4 and (P 2 −P 1 )+(P 4 −P 3 )<E the distance between P 1 and P 2 representing from 10% to 70% of the total thickness E of the silicon oxycarbide layer and the distance between P 3 and P 4 representing from 10% to 70% of the total thickness E of the silicon oxycarbide layer.
1. A glazing, comprising:
a transparent glass substrate comprising ions of an alkali metal, and
a transparent silicon oxycarbide layer (SiO x C y ), having a total thickness E, comprising a carbon-rich deep zone, extending from a depth P 3 to a depth P 4 , with a C/Si atomic ratio of greater than or equal to 0.5, and a carbon-poor surface zone, extending from a depth P 1 to a depth P 2 , with a C/Si atomic ratio of less than or equal to 0.4,
wherein
P 1 <P 2 <P 3 <P 4 ,
( P 2 −P 1 )+( P 4 −P 3 )< E,
a distance between P 1 and P 2 is from 10% to 70% of the total thickness E of the silicon oxycarbide layer, and
a distance between P 3 and P 4 is from 10% to 70% of the total thickness E of the silicon oxycarbide layer.
2. The glazing of claim 1 , wherein the total thickness E of the silicon oxycarbide layer is between 10 and 200 nm.
3. The glazing of claim 1 , wherein the transparent silicon oxycarbide layer is a non-porous layer having a refractive index between 1.45 and 1.9.
4. The glazing of claim 1 , having a b* (CIELab) value between −2 and +3.
5. The glazing of claim 1 , wherein the total thickness E of the silicon oxycarbide layer is between 20 and 100 nm.
6. The glazing of claim 1 , having a b* (CIELab) value between −1.5 and +2.0.
7. A process for manufacturing the glazing of claim 1 , the process comprising:
first depositing, by chemical vapor deposition (CVD), a carbon-rich silicon oxycarbide layer onto at least one part of a surface of a mineral glass substrate, by contacting the surface with a gas flow comprising ethylene (C 2 H 4 ), silane (SiH 4 ), carbon dioxide (CO 2 ), and nitrogen (N 2 ) with an ethylene/silane (C 2 H 4 /SiH 4 ) volume ratio of less than or equal to 3.3, at a temperature between 600° C. and 680° C.,
second, either
depositing, by CVD, a carbon-poor silicon oxycarbide layer onto the carbon-rich silicon oxycarbide layer with a gas flow comprising ethylene (C 2 H 4 ), silane (SiH 4 ), carbon dioxide (CO 2 ), and nitrogen (N 2 ) with an ethylene/silane (C 2 H 4 /SiH 4 ) volume ratio of less than or equal to 3.4, at a temperature between 600° C. and 680° C., or
depositing a layer of silica (SiO 2 ) by CVD, plasma-enhanced CVD (PECVD), or magnetron sputtering onto the carbon-rich silicon oxycarbide layer.
8. The process of claim 7 , further comprising annealing and/or forming at a temperature between 580° C. and 700° C.
9. The process of claim 7 , further comprising annealing and/or forming at a temperature between 600° C. and 680° C.