Ion exchangeable glass, glass ceramics and methods for making the same
Glass-ceramics and precursor glasses that are crystallizable to glass-ceramics are disclosed. The glass-ceramics of one or more embodiments include rutile, anatase, armalcolite or a combination thereof as the predominant crystalline phase. Such glasses and glass-ceramics may include compositions of, in mole %: SiO 2 in the range from about 45 to about 75; Al 2 O 3 in the range from about 4 to about 25; P 2 O 5 in the range from about 0 to about 10; MgO in the range from about 0 to about 8; R 2 O in the range from about 0 to about 33; ZnO in the range from about 0 to about 8; ZrO 2 in the range from about 0 to about 4; B 2 O 3 in the range from about 0 to about 12, and one or more nucleating agents in the range from about 0.5 to about 12. In some glass-ceramic articles, the total crystalline phase includes up to 20% by weight of the glass-ceramic article.
1. A glass-ceramic article comprising:
a predominant crystalline phase comprising anatase, rutile, or a combination thereof; and a composition, in mol %, comprising:
SiO 2 in the range from about 45 to about 75;
Al 2 O 3 in the range from about 4 to about 25;
P 2 O 5 in the range from about 0.1 to about 10;
MgO in the range from about 0 to about 4;
R 2 O in the range from about 0 to about 33;
ZnO in the range from about 0 to about 5;
ZrO 2 in the range from about 0 to about 4;
TiO 2 in the range from about 0.5 to about 10; and
B 2 O 3 in the range from about 0 to 4.44,
wherein R 2 O comprises one or more of Na 2 O, Li 2 O and K 2 O.
2. The glass-ceramic article of claim 1 , wherein (R 2 O—Al 2 O 3 ) is in the range from about −4 to about 4.
3. The glass-ceramic article of claim 1 , wherein the composition comprises, in mol %,
Li 2 O in the range from about 0 to about 12;
Na 2 O in the range from about 4 to about 20; and
K 2 O in the range from about 0 to about 2.
4. The glass-ceramic article of claim 1 , wherein the composition comprises, in mol %, B 2 O 3 in the range from about 2 to 4.41.
5. The glass-ceramic article of claim 1 further comprising a total crystalline phase of up to 20% by weight.
6. The glass-ceramic article of claim 1 , further comprising a compressive stress layer extending from a surface of the glass-ceramic article to a depth of the compressive stress layer, the compressive stress layer comprising a compressive stress of about 200 MPa or greater and the depth of compressive stress layer of about 15 μm or greater.
7. The glass-ceramic article of claim 6 , further exhibiting a Vickers indentation crack initiation load of about 10 kgf or greater.
8. A glass-ceramic article comprising:
a predominant crystalline phase comprising anatase, rutile, or a combination thereof,
wherein the glass-ceramic article is formed from a precursor glass having a liquidus viscosity of about 20 kP or greater.
9. The glass-ceramic article of claim 8 , wherein the predominant crystalline phase comprises crystals having a length of about 1 μm or less and a width of about 50 nm or less.
10. The glass-ceramic article of claim 8 , wherein the combined amount of anatase and rutile is less than about 12 wt. %, of the glass-ceramic article.
11. The glass-ceramic article of claim 8 , further comprising
a color presented in CIELAB color space coordinates determined from specular reflectance measurements selected from any one of:
CIE a* in the range from about −2 to about 8, CIE b* in the range from about −7 to about 30, and CIE L* in the range from about 85 to about 100; and
CIE a* in the range from about −1 to about 0, CIE b* in the range from about −7 to about −3, and CIE L* in the range from about 85 to about 100.
12. The glass-ceramic article of claim 8 , further exhibiting a Vickers indentation crack initiation load of about 10 kgf or greater.
13. An electronic or portable computing device comprising the glass-ceramic article of claim 1 .
14. An electronic or portable computing device comprising the glass-ceramic article of claim 8 .