Methods of making colored glass by surface modification

1. A method of making colored glass in a float glass process, comprising the steps of:

melting glass batch materials in a furnace to form a glass melt;

transporting the glass melt into a float glass chamber having a flame spray device, the glass melt forming a float glass ribbon;

supplying coating materials to the flame spray device to form a spray containing coating particles; and

directing the spray onto the float glass ribbon to diffuse the coating particles into the surface of the float glass ribbon to form a resultant glass sheet of a desired color,

wherein said coating particles comprise metal oxide nanoparticles comprising iron and at least one of cobalt and manganese, and wherein the desired color is neutral gray.

2. The method of claim 1 , including varying the coating materials to vary the color of the resultant glass sheet.

3. The method of claim 1 , wherein the glass melt has a green hue.

4. The method of claim 1 , wherein the glass melt is essentially colorless or clear.

5. The method of claim 1 , wherein the glass batch materials include iron and the glass batch materials are essentially free of selenium.

6. The method of claim 1 , including directing the spray onto the float glass at a location in the float chamber where the glass ribbon has a temperature in the range of 600° C. to 800° C.

7. The method of claim 6 , wherein the desired color is created by mixing colorants of oxide nanoparticles.