Low-maintenance coatings, and methods for producing low-maintenance coatings

1. A substrate having a major surface on which there is a low-maintenance coating, the low-maintenance coating including a functional film comprising both titanium oxide and tungsten oxide, wherein the functional film has a tungsten load characterized by a metal-only weight ratio of between about 0.01 and about 0.34, this ratio being the weight of the tungsten in the film divided by the weight of the titanium in the film, wherein the substrate is glass in an annealed state, and wherein the functional film has a thickness of greater than 40 Å and less than 100 Å and yet the low-maintenance coating has an acetone decomposition rate of greater than 1.4×10 −10 moles/(liter)(second).

2. The substrate of claim 1 wherein the acetone decomposition rate is greater than 1.91×10 −10 moles/(liter)(second).

3. The substrate of claim 1 wherein the low-maintenance coating, if tempered, experiences an increase of its acetone decomposition rate by more than a factor of 1.5 due to the tempering.

4. The substrate of claim 1 wherein the low-maintenance coating, if tempered, experiences an increase of its acetone decomposition rate, the increase resulting in the acetone decomposition rate being greater than 1.8×10 −10 moles/(liter)(second).

5. The substrate of claim 1 wherein the low-maintenance coating, if tempered, experiences an increase of its acetone decomposition rate, the increase resulting in the acetone decomposition rate being greater than 4×10 −10 moles/(liter)(second).

6. The substrate of claim 1 wherein the functional film has a thickness of about 50-80 Å.

7. The substrate of claim 1 wherein the low-maintenance coating has an average surface roughness of between 0.35 nm and 3.0 nm.

8. The substrate of claim 1 wherein the low-maintenance coating includes a base film between the substrate and the functional film, and wherein the base film and the functional film have a combined thickness of less than about 350 Å.

9. The substrate of claim 1 wherein the functional film is a substantially homogenous film defining an exposed, outermost face of the low-maintenance coating.

10. The substrate of claim 1 wherein the substrate is a transparent pane that is part of a multiple-pane insulating glazing unit having a between-pane space, wherein the major surface bearing the low-maintenance coating faces away from the between-pane space of the unit.

11. The substrate of claim 1 wherein the substrate is part of a triple-pane insulating glazing unit.

12. The substrate of claim 1 wherein the substrate is part of a multiple-pane insulating glazing unit having two exterior major surfaces each bearing a low-maintenance coating comprising both titanium oxide and tungsten oxide.

13. A substrate having a major surface on which there is a low-maintenance coating, the low-maintenance coating including a functional film comprising both titanium oxide and tungsten oxide, wherein the functional film has a tungsten load characterized by a metal-only weight ratio of between about 0.01 and about 0.34, this ratio being the weight of the tungsten in the film divided by the weight of the titanium in the film, wherein the substrate is glass in a tempered state, and wherein the functional film has a thickness of greater than 40 Å and less than 100 Å and yet the low-maintenance coating has an acetone decomposition rate of greater than 1.8×10 −10 moles/(liter)(second).

14. The substrate of claim 13 wherein the acetone decomposition rate of the low-maintenance coating is greater than 4.0×10 −10 moles/(liter)(second).

15. The substrate of claim 13 wherein the functional film has a thickness of about 50-80 Å.

16. The substrate of claim 13 wherein the low-maintenance coating includes a base film between the substrate and the functional film, and wherein the base film and the functional film have a combined thickness of less than about 350 Å.

17. A substrate having a major surface on which there is a low-maintenance coating that includes a base film and a functional film, the functional film comprising both titanium oxide and tungsten oxide, wherein the functional film has a tungsten load characterized by a metal-only weight ratio of between about 0.01 and about 0.34, this ratio being the weight of the tungsten in the film divided by the weight of the titanium in the film, wherein the functional film has a thickness of greater than 40 Å and less than 100 Å, the base film being a high-rate sputtered film deposited using at least one target in an atmosphere into which both inert gas and reactive gas are flowed, wherein an inflow rate for the inert gas divided by an inflow rate for the reactive gas is between 0.4 and 9, the functional film being a high-rate sputtered film deposited from at least one target having a sputterable material comprising both titanium oxide and tungsten oxide, wherein the substrate is glass in an annealed state, and wherein the low-maintenance coating has an acetone decomposition rate of greater than 1.4×10 −10 moles/(liter)(second).

18. The substrate of claim 17 wherein an average surface roughness of the low-maintenance coating is between 0.35 nm and 5.0 nm.

19. The substrate of claim 17 wherein the sputterable target material used in depositing the functional film includes: i) tungsten in oxide form, ii) TiO, and iii) TiO 2 .

20. The substrate of claim 17 wherein the acetone decomposition rate is greater than 2.0×10 −10 moles/(liter)(second).

21. A substrate having a major surface on which there is a low-maintenance coating, the low-maintenance coating having only a single photocatalytic layer, the photocatalytic layer comprising both titanium oxide and tungsten oxide throughout an entire thickness of the layer, wherein the photocatalytic layer has a tungsten load characterized by a metal-only weight ratio of between about 0.01 and about 0.34, this ratio being the weight of the tungsten in the layer divided by the weight of the titanium in the layer, wherein the substrate is glass in an annealed state, and wherein the photocatalytic layer has a thickness of greater than 40 Å and less than 100 Å and yet the low-maintenance coating has an acetone decomposition rate of greater than 1.4×10 −10 moles/(liter)(second).

22. The substrate of claim 21 wherein the acetone decomposition rate is greater than 2.1×10 −10 moles/(liter)(second).

23. A substrate having a major surface on which there is a low-maintenance coating, the low-maintenance coating having only a single photocatalytic layer, the photocatalytic layer comprising both titanium oxide and tungsten oxide throughout an entire thickness of the layer, wherein the photocatalytic layer has a tungsten load characterized by a metal-only weight ratio of between about 0.01 and about 0.34, this ratio being the weight of the tungsten in the layer divided by the weight of the titanium in the layer, wherein the substrate is glass in a tempered state, and wherein the photocatalytic layer has a thickness of greater than 40 Å and less than 100 Å and yet the low-maintenance coating has an acetone decomposition rate of greater than 1.8×10 −10 moles/(liter)(second).

24. The substrate of claim 23 wherein the acetone decomposition rate is greater than 6.75×10 −10 moles/(liter)(second).

25. The substrate of claim 13 wherein the substrate has a haze value of less than 0.30.

26. The substrate of claim 17 wherein the low maintenance coating, if tempered, experiences an increase of its acetone decomposition rate by more than a factor of 1.5 due to the tempering.

27. The substrate of claim 17 wherein the low maintenance coating, if tempered, experiences an increase of its acetone decomposition rate, the increase resulting in the acetone decomposition rate being greater than 1.8×10 −10 moles/(liter)(second).

28. The substrate of claim 17 wherein the low maintenance coating, if tempered, experiences an increase of its acetone decomposition rate, the increase resulting in the acetone decomposition rate being greater than 4×10 −10 moles/(liter)(second).

29. The substrate of claim 18 wherein an average surface roughness of the low-maintenance coating is between 0.4 nm and 3.0 nm.

30. The substrate of claim 21 wherein the low maintenance coating, if tempered, experiences an increase of its acetone decomposition rate by more than a factor of 1.5 due to the tempering.

31. The substrate of claim 21 wherein the low maintenance coating, if tempered, experiences an increase of its acetone decomposition rate, the increase resulting in the acetone decomposition rate being greater than 1.8×10 −10 moles/(liter)(second).

32. The substrate of claim 21 wherein the low maintenance coating, if tempered, experiences an increase of its acetone decomposition rate, the increase resulting in the acetone decomposition rate being greater than 4×10 −10 moles/(liter)(second).

33. The substrate of claim 23 wherein the substrate has a haze value of less than 0.30.