Physical vapor deposited layers for protection of glass surfaces
A scratch-resistant glass substrate is prepared by forming a hard, scratch-resistant layer over a major surface of the substrate. The layer is formed from an inorganic material such as a metal oxide, metal nitride, metal carbide, or metal boride using, for example, physical vapor deposition such as reactive or non-reactive sputtering at a process temperature of less than 500° C. The inorganic layer is resistant to micro-ductile scratching, which can safeguard the visible appearance of the glass substrate in use. The glass substrate can include chemically-strengthened glass.
1. A scratch-resistant glass article, comprising
a glass substrate having opposing major surfaces; and
an inorganic, optically-transparent layer formed over a majority of a first major surface, wherein the glass substrate comprises chemically-strengthened glass having a compressive stress of about 300 MPa or greater,
wherein the scratch-resistant glass article exhibits a scratch depth reduction, when scratched using a Berkovich indenter and a load of up to about 160 mN, of at least 20%, when compared to a glass substrate without the inorganic, optically-transparent layer provided over a majority of a first major surface.
2. The scratch-resistant glass article of claim 1 , further exhibiting a scratch width reduction, when scratched using a Berkovich indenter and a load of up to about 160 mN, of at least 20%, when compared to a glass substrate without the low-temperature-deposited inorganic, optically-transparent layer provided over a majority of a first major surface.
3. The article according to claim 1 , wherein the inorganic layer comprises a metal oxide, a metal nitride, a metal carbide, a metal boride, or a combination thereof.
4. The article according to claim 3 , wherein the metal is selected from the group consisting of B, Al, Si, Ti, V, Cr, Y, Zr, Nb, Mo, Sn, Hf, Ta and W.
5. The article according to claim 1 , wherein the inorganic layer has a Berkovich indenter hardness of at least 9 GPa.
6. The article according to claim 1 , wherein the inorganic layer has a hardness that is at least 10% greater than a hardness of the glass substrate.
7. The article according to claim 1 , wherein the inorganic layer has a thickness ranging from about 10 nm to 3 microns.
8. The article according to claim 1 , wherein the inorganic layer is a contiguous layer.
9. The article according to claim 1 , wherein the inorganic layer is formed in direct physical contact with the glass substrate.
10. The article according to claim 1 , wherein an anti-reflective layer or a stress-reduction layer is formed between the glass substrate and the inorganic layer.
11. The article according to claim 1 , wherein the glass substrate has a thickness ranging from about 100 microns to 5 mm.
12. The article according to claim 1 , wherein the first major surface is substantially planar.
13. The article according to claim 1 , wherein the inorganic layer is water clear.
14. The article according to claim 1 , wherein the inorganic layer has a refractive index of less than about 3 at visible wavelengths.
15. The article according to claim 1 , wherein the inorganic layer has a refractive index between about 1.4 and 2 at visible wavelengths.
16. The article according to claim 1 , wherein the inorganic layer has a reflectance of less than about 40% at visible wavelengths.
17. The article according to claim 1 , wherein the inorganic layer is under a state of compressive stress.
18. The article according to claim 1 , where the inorganic layer is substantially free of microductile scratches.