Coated substrate

1. A coated substrate comprising:

a substrate,

a first coating comprising one or more layers deposited by physical vapor deposition provided on at least a part of at least one face of the substrate, wherein the first coating is a solar control or insulating low E coating, and

a sol-gel coating provided on at least a part of said face above the first coating,

wherein the sol-gel coating comprises a mixture of titanium oxide, zirconium oxide, silicon oxide and optionally bismuth oxide and/or cerium oxide in theoretical weight ratios of:

titanium oxide TiO 2 /silicon oxide SiO 2 ranging from 0.10 to 3,

zirconium oxide ZrO 2 /silicon oxide SiO 2 ranging from 0.10 to 3,

bismuth oxide Bi 2 O 3 /silicon oxide SiO 2 ranging from 0 to 0.03, and

cerium oxide CeO 2 /silicon oxide SiO 2 ranging from 0 to 0.03.

2. The coated substrate according to claim 1 , wherein the sol-gel coating is provided on at least a part of the face of the substrate provided with the first coating and in direct contact with the first coating.

3. The coated substrate according to claim 1 , wherein the sol-gel coating is provided at least substantially on the entire first coating and in direct contact with the first coating.

4. The coated substrate according to claim 1 , wherein the sol-gel coating comprises a mixture of titanium oxide, zirconium oxide, silicon oxide, and bismuth oxide in theoretical weight ratios of:

titanium oxide TiO 2 /silicon oxide SiO 2 ranging from 0.10 to 3,

zirconium oxide ZrO 2 /silicon oxide SiO 2 ranging from 0.10 to 3, and

bismuth oxide Bi 2 O 3 /silicon oxide SiO 2 ranging from 0 to 0.03.

5. The coated substrate according to claim 1 , wherein the sol-gel coating comprises a mixture of titanium oxide, zirconium oxide, silicon oxide, and cerium oxide in theoretical weight ratios of:

titanium oxide TiO 2 /silicon oxide SiO 2 ranging from 0.10 to 3,

zirconium oxide ZrO 2 /silicon oxide SiO 2 ranging from 0.10 to 3, and

cerium oxide CeO 2 /silicon oxide SiO 2 ranging from 0 to 0.03.

6. The coated substrate according to claim 1 , wherein the sol-gel coating comprises a mixture of titanium oxide, zirconium oxide, silicon oxide, and optionally bismuth oxide and/or cerium oxide in theoretical weight ratios of:

titanium oxide TiO 2 /silicon oxide SiO 2 ranging from 0.25 to 2.5,

zirconium oxide ZrO 2 /silicon oxide SiO 2 ranging from 0.25 to 2.5,

bismuth oxide Bi 2 O 3 /silicon oxide SiO 2 ranging from 0 to 0.02, and

cerium oxide CeO 2 /silicon oxide SiO 2 ranging from 0 to 0.02.

7. The coated substrate according to claim 1 , wherein the sol-gel coating comprises a mixture of titanium oxide, zirconium oxide, silicon oxide, and optionally bismuth oxide and/or cerium oxide in theoretical weight ratios of:

titanium oxide TiO 2 /silicon oxide SiO 2 ranging from 0.5 to 2,

zirconium oxide ZrO 2 /silicon oxide SiO 2 ranging from 0.5 to 2,

bismuth oxide Bi 2 O 3 /silicon oxide SiO 2 ranging from 0 to 0.01, and

cerium oxide CeO 2 /silicon oxide SiO 2 ranging from 0 to 0.01.

8. The coated substrate according to claim 1 , wherein the sol-gel coating comprises a mixture of titanium oxide, zirconium oxide, silicon oxide, and optionally bismuth oxide and/or cerium oxide in theoretical weight ratios of:

titanium oxide TiO 2 /silicon oxide SiO 2 ranging from 1 to 1.5,

zirconium oxide ZrO 2 /silicon oxide SiO 2 ranging from 1 to 1.5,

bismuth oxide Bi 2 O 3 /silicon oxide SiO 2 ranging from 0 to 0.03, and

cerium oxide CeO 2 /silicon oxide SiO 2 ranging from 0 to 0.03.

9. The coated substrate according to claim 1 , wherein a thickness of the sol-gel coating is from 50 to 500 nm.

10. The coated substrate according to claim 1 , wherein the sol gel coating is formed by applying a sol gel solution on at least one face of the substrate.

11. The coated substrate according to claim 1 , wherein the substrate is a glass substrate.

12. The coated substrate according to claim 11 , wherein the glass substrate is heat treated.

13. The coated substrate according to claim 12 , wherein the glass substrate is tempered.

14. A glazing unit comprising at least one coated substrate according to claim 11 , wherein a face of the coated substrate provided with the first coating and the sol-gel coating is facing an outside of the unit.

15. The glazing unit according to claim 14 , wherein the glazing unit is a single glazing unit comprising one glass panel.

16. The glazing unit according to claim 14 , wherein the glazing unit is a multiple glazing unit comprising at least two glass panels separated by an interspace.

17. A process for making the coated substrate according to claim 1 , comprising:

a) forming the first coating on at least a part of at least one face of the substrate,

b) applying the first sol-gel solution on at least a part of said face above the first coating, and

c) curing the sol-gel solution to obtain a sol-gel coating comprising a mixture of titanium oxide, zirconium oxide, silicon oxide and optionally bismuth oxide and/or cerium oxide in theoretical weight ratios of:

titanium oxide TiO 2 /silicon oxide SiO 2 ranging from 0.10 to 3,

zirconium oxide ZrO 2 /silicon oxide SiO 2 ranging from 0.10 to 3,

bismuth oxide Bi 2 O 3 /silicon oxide SiO 2 ranging from 0 to 0.03, and

cerium oxide CeO 2 /silicon oxide SiO 2 ranging from 0 to 0.03.

18. The process according to claim 17 , wherein the substrate is a glass substrate.

19. The process according to claim 18 , further comprising, after the curing, d) heating the glass substrate.

20. The process according to claim 19 , wherein the heating of the glass substrate is a tempering step.