BACKGROUND OF THE INVENTION

This invention relates in general to a chemical vapor deposition (CVD) process for depositing a coating. The invention also relates to the coating formed according to the CVD process.

Forming glass articles by depositing coatings on a glass substrate is known. Also, it is known to utilize a color suppression interlayer on a glass substrate to reflect and refract light to interfere with the observance of iridescence. In certain instances, the color suppression interlayer is formed by depositing two coating layers. However, depositing a color suppression interlayer that requires two coating layers adds cost and complexity to forming the glass article. Furthermore, the coating materials known to be utilized in the first coating of a two-layer color suppression interlayer fail to block sodium diffusion from the glass substrate.

Thus, it would be desirable to provide a single layer color suppression interlayer. It would also be desirable if said single layer color suppression interlayer could block sodium diffusion from the glass substrate.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a chemical vapor deposition process for depositing a coating, comprising:

providing a glass substrate;

forming a gaseous mixture comprising a silicon-containing compound, an oxygen-containing compound, a radical scavenger, and a titanium-containing compound; and

directing the gaseous mixture toward and along the glass substrate, and reacting the mixture over the glass substrate to form the coating thereover, the coating having a refractive index of 1.48 or more.

Preferably the coating comprises silicon oxide and titanium oxide, with a ratio of titanium to silicon of less than 1.

Preferably the gaseous mixture comprises 0.1 to 5% of the titanium-containing compound by volume. More preferably the gaseous mixture comprises 0.1 to 2% of the titanium-containing compound by volume. Even more preferably the gaseous mixture comprises 0.1 to 1% of the titanium-containing compound by volume.

Preferably the coating is formed directly on the glass substrate.

Preferably the coating is deposited over the glass substrate at essentially atmospheric pressure.

Preferably the silicon oxide is silicon dioxide.

Preferably the titanium oxide is titanium dioxide.

Preferably the coating has a refractive index of 1.50 to 1.85. More preferably the coating has a refractive index of 1.65 to 1.85.

Preferably the glass substrate is moving at the time of forming the coating.

Preferably the glass substrate is a float glass ribbon.

Preferably the coating is formed at a dynamic deposition rate of 280 nm×m/min or more.

Preferably the gaseous mixture is formed prior to being fed through a coating apparatus or within the coating apparatus, the gaseous mixture exiting the coating apparatus and being directed toward and along the glass substrate to form the mixed metal oxide coating.

Preferably the silicon-containing compound is a silane compound. Preferably the silane compound is monosilane or disilane.

Preferably the oxygen-containing compound is molecular oxygen. In the context of the present invention the term “compound” may include compounds and molecules, such as molecular oxygen.

In an alternative embodiment the oxygen-containing compound may be an inorganic oxygen-containing compound. Preferably the inorganic oxygen-containing compound is selected from the group consisting of water, carbon dioxide, nitric oxide, nitrogen dioxide, and nitrous oxide.

Preferably the radical scavenger comprises a hydrocarbon gas. Preferably the hydrocarbon gas is ethylene or propylene. More preferably the hydrocarbon gas is ethylene.

Preferably the titanium-containing compound is an inorganic titanium-containing compound. More preferably the titanium-containing compound is an inorganic, halogenated titanium-containing compound. Most preferably the titanium-containing compound is titanium tetrachloride.

In an alternative embodiment the titanium-containing compound may be an organic titanium-containing compound. In said alternative embodiment the titanium-containing compound is preferably a titanium alkoxide compound. More preferably the titanium-containing compound is titanium isopropoxide or titanium ethoxide.

According to a second aspect of the present invention there is provided a coated glass article comprising a glass substrate and a coating formed over the glass substrate, the coating comprising silicon oxide and titanium oxide, wherein the silicon oxide comprises more than 50 mol % of the coating and the coating has a refractive index of 1.48 or more.

Preferably the coating is formed directly on the glass substrate.

Preferably the coating has a ratio of titanium to silicon of less than one, more preferably less than 0.95, even more preferably less than 0.90. Preferably the coating has a ratio of titanium to silicon of at least 0.01, more preferably at least 0.05, even more preferably at least 0.10.

Preferably the coating has a refractive index of 1.50 or more. More preferably the coating has a refractive index of 1.50 to 1.85. Even more preferably the coating has a refractive index of 1.53 to 1.85. Even more preferably the coating has a refractive index of 1.65 to 1.85.

Preferably the silicon oxide comprises more than 55 mol % of the coating, more preferably more than 60 mol % of the coating.

