Zirconia-toughened glass ceramics

Abstract

ZrO2-toughened glass ceramics having high molar fractions of tetragonal ZrO2 and fracture toughness value of greater than 1.8 MPa·m1/2. The glass ceramic may also include also contain other secondary phases, including lithium silicates, that may be beneficial for toughening or for strengthening through an ion exchange process. Additional second phases may also decrease the coefficient of thermal expansion of the glass ceramic. A method of making such glass ceramics is also provided.

1 . A glass ceramic comprising at least two crystalline phases,
 the first crystalline phase comprising a ZrO 2  phase and   the second crystalline phase comprising a lithium silicate phase,   the glass ceramic further comprising a residual glass phase,   
       wherein the glass ceramic has fracture toughness of from 1.8 to 10 MPa·m 1/2 , the first crystalline phase is a tetragonal ZrO 2  phase, and the second crystalline phase is a lithium disilicate phase. 
     
     
         2 . (canceled) 
     
     
         3 . (canceled) 
     
     
         4 . The glass ceramic of  claim 1 , comprising the composition:
 50-80 mol % SiO 2 ,   18-40 mol % Li 2 O,   1.5-25 mol % ZrO 2 , and   greater than 0-5 mol % P 2 O 5 .   
     
     
         5 . The glass ceramic of  claim 1 , wherein the at least two crystalline phases comprise a weight percent (wt %) of the total glass ceramic, measured as the (((weight of the at least two crystalline phases)/(total weight of the glass ceramic))*100), and wherein the at least two crystalline phases comprise from 60-95 wt % of the total glass ceramic. 
     
     
         6 . (canceled) 
     
     
         7 . The glass ceramic of  claim 1 , wherein the tetragonal ZrO 2  comprises a weight percent (wt %) of the total ZrO 2  in the glass ceramic, measured as the (((weight of the tetragonal ZrO 2 )/(total weight of ZrO 2  in the glass ceramic))*100), and wherein the tetragonal ZrO 2  comprises 5-50 wt % of ZrO 2  in the glass ceramic. 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . The glass ceramic of  claim 1 , wherein the tetragonal ZrO 2  crystals have an average crystal size from 0.1 to 10 μm along their longest dimension. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . The glass ceramic of  claim 1 , wherein the lithium disilicate comprises a weight percent (wt %) of the total glass ceramic, measured as the (((weight of the lithium disilicate)/(total weight the glass ceramic))*100), and wherein the lithium disilicate comprises from 25-60 wt % of the total glass ceramic composition. 
     
     
         14 . (canceled) 
     
     
         15 . The glass ceramic of  claim 1 , wherein the lithium disilicate crystals have an average crystal size from 1 to 20 μm along their longest dimension. 
     
     
         16 . (canceled) 
     
     
         17 . The glass ceramic of  claim 1 , further comprising one or more additional crystalline phases, wherein the one or more additional crystalline phases is selected from the group consisting of lithium aluminosilicate, cristobalite, β-spodumene, lithiophosphate, lithium orthophosphate, β-quartz solid solution, α-quartz, baddeleyite, lithium metasilicate, cristobalite, monoclinic zirconia, cubic zirconia, zekzerite, (Na,Li)ZrSi 6 O 18  and combinations thereof. 
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . The glass ceramic of  claim 17 , wherein the one or more additional crystalline phases is two or more phases selected from the group consisting of a monoclinic ZrO 2  and at least one of lithium aluminosilicate, β-spodumene solid solution, β-quartz solid solution, or α-quartz, wherein the monoclinic ZrO 2  is from >0-5 wt % of the glass ceramic. 
     
     
         21 . The glass ceramic of  claim 1 , further comprising:
 0-5 mol % Al 2 O 3  and   0-5 mol % Na 2 O.   
     
     
         22 . The glass ceramic of  claim 1 , further comprising:
 0-14 mol % R 2 O   0-10 mol % MO   0-5 mol % TMO, and   0-5 mol % REO.   
     
     
         23 . The glass ceramic of  claim 1 , comprising:
 55-70 mol % SiO 2      18-30 mol % Li 2 O   4-20 mol % ZrO 2 , and   0.2-5 mol % P 2 O 5 .   
     
     
         24 . The glass ceramic of  claim 1 , comprising:
 58-69 mol % SiO 2      25-36 mol % Li 2 O   6-15 mol % ZrO 2      >0-5 mol % Al 2 O 3      0-5 mol % Na 2 O   0-5 mol % B 2 O 3      0.2-3 mol % P 2 O 5      0-8 mol % MO   0-5 mol % TMO, and   0-5 mol % REO.   
     
     
         25 . The glass ceramic of  claim 1 , further comprising >0-5 mol % REO. 
     
     
         26 . (canceled) 
     
     
         27 . The glass ceramic of  claim 1 , wherein the glass ceramic is free of Rb 2 O and Cs 2 O. 
     
     
         28 . The glass ceramic of  claim 1 , further comprising >0-5 mol % TiO 2 . 
     
     
         29 . The glass ceramic of  claim 1 , further comprising >0-3 mol % ZnO. 
     
     
         30 . The glass ceramic of  claim 1 , further comprising >0-4 mol % of a color component. 
     
     
         31 . The glass ceramic of  claim 30 , wherein the color component comprises Fe 2 O 3 , V 2 O 5 , Cr 2 O 3 , MnO 2 , NiO, CuO, Co 3 O 4  and combinations thereof. 
     
     
         32 . The glass ceramic of  claim 1 , wherein the glass ceramic exhibits a color presented in CIELAB color space coordinates: a*=from about −1 to about +3; b*=from about −7 to about +3; and L*>85. 
     
     
         33 . (canceled) 
     
     
         34 . The glass ceramic of  claim 1 , wherein the glass ceramic exhibit a color presented in CIELAB color space coordinates: a*=from about −1 to about 1; b*=from about −4 to about 1; and L*<60. 
     
     
         35 . (canceled) 
     
     
         36 . The glass ceramic of  claim 1 , wherein the glass ceramic has a fracture toughness of from 2 to 10 MPa·m 1/2  as measured by Chevron notch short bar methods. 
     
     
         37 - 67 . (canceled)