Lithium silicate glass ceramic and glass with rubidium oxide content

Abstract

The invention relates to the use of lithium silicate glass ceramics and glasses with rubidium oxide content for coating an oxide ceramic, a metal or an alloy.

Claims

1. Composite material which comprises a lithium silicate glass ceramic or a lithium silicate glass, which comprise the following components TABLE-US-00006 Component wt.-% SiO.sub.2 56.0 to 73.0 Li.sub.2O 13.0 to 19.0 Rb.sub.2O 3.0 to 9.0 A1.sub.2O.sub.3 2.0 to 5.0 P.sub.2O.sub.5 2.0 to 6.0 ZrO.sub.2 0 to 4.5 on a substrate selected from oxide ceramics, metals and alloys.

2. Composite material according to claim 1, wherein the substrate is a dental restoration.

3. Process for coating a substrate selected from oxide ceramics, metals and alloys, in which a lithium silicate glass ceramic or a lithium silicate glass which comprise the following components TABLE-US-00007 Component wt.-% SiO.sub.2 56.0 to 73.0 Li.sub.2O 13.0 to 19.0 Rb.sub.2O 3.0 to 9.0 A1.sub.2O.sub.3 2.0 to 5.0 P.sub.2O.sub.5 2.0 to 6.0 ZrO.sub.2 0 to 4.5 is applied to the substrate.

4. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise at least one of the following components in the given amounts TABLE-US-00008 Component wt.-% SiO.sub.2 56.9 to 72.0 Li.sub.2O 14.2 to 18.0 Rb.sub.2O 3.7 to 7.7 Al.sub.2O.sub.3 2.5 to 4.5 P.sub.2O.sub.5 3.1 to 5.0 ZrO.sub.2 0 to 4.0 Transition 0 to 7.5, metal oxide wherein the transition metal oxide is selected from the group consisting of oxides of yttrium, oxides of transition metals with an atomic number from 41 to 79 and mixtures of these oxides.

5. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise 58.0 to 72.0 wt.-% SiO.sub.2.

6. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise 3.7 to 7.7 wt.-% Rb.sub.2O.

7. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise 2.5 to 4.0 wt.-% Al.sub.2O.sub.3.

8. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise less than 2.5 wt.-% Cs.sub.2O.

9. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise less than 4.0 wt.-% Na.sub.2O and/or K.sub.2O.

10. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise less than 3.8 wt.-% BaO.

11. Process according to claim 3, in which a lithium silicate glass ceramic is used which comprises lithium metasilicate as main crystal phase and has a bending strength in the range of about 180 to 300 MPa and/or a fracture toughness, measured as K.sub.IC value, of at least about 2.0 MPa.Math.m.sup.0.5.

12. Process according to claim 11, wherein the fracture toughness, measured as K.sub.IC value, is at least about 2.3 MPa.Math.m.sup.0.5.

13. Process according to claim 3, in which a lithium silicate glass ceramic is used which comprises lithium disilicate as main crystal phase and has a bending strength in the range of about 400 to 700 MPa and/or a fracture toughness, measured as K.sub.IC value, of at least about 2.0 MPa.Math.m.sup.0.5.

14. Process according to claim 13, wherein the fracture toughness, measured as K.sub.IC value, is at least about 2.3 MPa.Math.m.sup.0.5.

15. Process according to claim 3, in which a lithium silicate glass is used.

16. Process according to claim 15, wherein the lithium silicate glass comprises nuclei which are suitable for forming lithium metasilicate and/or lithium disilicate crystals.

17. Process according to claim 3, in which the substrate is an oxide ceramic.

18. Process according to claim 17, in which the substrate comprises a zirconium oxide ceramic.

19. Process according to claim 3, in which the substrate is a metal or an alloy.

20. Process according to claim 19, wherein the alloy comprises a non-precious metal alloy.

21. Process according to claim 3, in which the substrate is a dental restoration.

22. Process according to claim 21, wherein the dental restoration comprises a bridge, an inlay, an onlay, a veneer, an abutment, a partial crown, a crown or a facet.

23. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass is applied to the substrate by sintering.

24. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass is applied to the substrate by joining.

25. Process according to claim 24, in which the lithium silicate glass ceramic or the lithium silicate glass is shaped to a desired geometry by machining or by hot pressing before joining.

26. Process according to claim 3, in which a coating is obtained which comprises a lithium silicate glass ceramic that comprises lithium disilicate as main crystal phase, and which has a bending strength in the range of about 400 to 700 MPa and/or a fracture toughness, measured as K.sub.IC value, of at least about 2.0 MPa.Math.m.sup.0.5.

27. Process according to claim 26, wherein the fracture toughness, measured as K.sub.IC value, is at least about 2.3 MPa.Math.m.sup.0.5.

28. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise at least one of the following components in the given amounts TABLE-US-00009 Component wt.-% SiO.sub.2 56.9 to 72.0 Li.sub.2O 14.2 to 18.0 Rb.sub.2O 3.7 to 7.7 Al.sub.2O.sub.3 2.5 to 4.5 P.sub.2O.sub.5 3.1 to 5.0 ZrO.sub.2 0 to 4.0 Transition 0 to 7.0. metal oxide

29. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise 60.0 to 71.0 wt.-% SiO.sub.2.

30. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise 3.0 to 3.5 wt.-% Al.sub.2O.sub.3.

31. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise less than 1.5 wt.-% Cs.sub.2O.

32. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass is substantially free of Cs.sub.2O.

33. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise less than 3.5 wt.-% Na.sub.2O and/or K.sub.2O.

34. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise less than 2.0 wt.-% Na.sub.2O and/or K.sub.2O.

35. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass comprise less than 2.5 wt.-% BaO.

36. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass is substantially free of BaO.

37. Process according to claim 3, in which the lithium silicate glass ceramic or the lithium silicate glass is applied to the substrate by pressing-on.

38. Process according to claim 3, in which a lithium silicate glass ceramic is used which comprises lithium metasilicate as main crystal phase.

39. Process according to claim 3, in which a lithium silicate glass ceramic is used which comprises lithium disilicate as main crystal phase.

40. Process according to claim 3, in which a coating is obtained which comprises a lithium silicate glass ceramic that comprises lithium metasilicate as main crystal phase.

41. Process according to claim 3, in which a coating is obtained which comprises a lithium silicate glass ceramic that comprises lithium disilicate as main crystal phase.

42. Process for coating a substrate selected from oxide ceramics, metals and alloys, in which a lithium silicate glass ceramic or a lithium silicate glass which comprise the following components TABLE-US-00010 Component wt.-% SiO.sub.2 56.0 to 73.0 Li.sub.2O 13.0 to 19.0 Rb.sub.2O 3.0 to 9.0 Al.sub.2O.sub.3 2.0 to 5.0 P.sub.2O.sub.5 2.0 to 6.0 is applied to the substrate and in which a coating is obtained which comprises a lithium silicate glass ceramic that comprises lithium metasilicate as main crystal phase, and which has a bending strength in the range of about 180 to 300 MPa and/or a fracture toughness, measured as K.sub.IC value, of at least about 2.0 MPa.Math.m.sup.0.5.

43. Process according to claim 42, wherein the fracture toughness, measured as K.sub.IC value, is at least about 2.3 MPa.Math.m.sup.0.5.

44. Lithium silicate glass ceramic, which comprises the following components in the given amounts TABLE-US-00011 Component wt.-% SiO.sub.2 56.0 to 72.5 Li.sub.2O 13.0 to 19.0 Rb.sub.2O 3.0 to 9.0 Al.sub.2O.sub.3 2.0 to 5.0 P.sub.2O.sub.5 2.0 to 6.0 ZrO.sub.2 0 to 4.5 Transition 0 to 7.5, metal oxide wherein the transition metal oxide is selected from the group consisting of oxides of yttrium, oxides of transition metals with an atomic number from 41 to 79 and mixtures of these oxides.

45. Lithium silicate glass, which comprises the components of the glass ceramic according to claim 44.

46. Lithium silicate glass ceramic, which comprises the following components in the given amounts TABLE-US-00012 Component wt.-% SiO.sub.2 56.9 to 72.0 Li.sub.2O 14.2 to 18.0 Rb.sub.2O 3.7 to 7.7 Al.sub.2O.sub.3 2.5 to 4.5 P.sub.2O.sub.5 3.1 to 5.0 ZrO.sub.2 0 to 4.0 Transition 0 to 7.0, metal oxide wherein the transition metal oxide is selected from the group consisting of oxides of yttrium, oxides of transition metals with an atomic number from 41 to 79 and mixtures of these oxides.

Description

EXAMPLES

(1) A total of 15 glasses and glass ceramics according to the invention with the compositions given in Table I were produced by melting corresponding starting glasses followed by heat treatment for controlled nucleation and crystallization.

(2) For this, the starting glasses in an amount of 100 to 200 g were first melted from customary raw materials at 1450 to 1550 C., wherein the melting was very easily possible without formation of bubbles or streaks. By pouring the starting glasses into water, glass frits were produced which were then melted a second time at 1450 to 1550 C. for 1 to 3 h for homogenization. The obtained glass melts were then poured into pre-heated moulds to produce glass monoliths. All glass monoliths proved transparent.

(3) The glass monoliths were then converted to glasses and glass ceramics according to the invention by thermal treatment. The thermal treatments used for controlled nucleation and controlled crystallization are also given in Table I. The following meanings apply

(4) TABLE-US-00004 T.sub.N and t.sub.N Temperature and time used for nucleation T.sub.C and t.sub.C Temperature and time used for first crystallization T.sub.FC and t.sub.FC Temperature and time used for final crystallization T.sub.press and t.sub.press Temperature and time used for hot pressing

(5) It can be seen that a first heat treatment in the range of from 470 to 500 C. resulted in the formation of lithium silicate glasses with nuclei and these glasses crystallized as a result of further heat treatment at 600 to 710 C. (Examples 1-6, 8-9 and 13) to form glass ceramics with lithium metasilicate as main crystal phase or as a result of heat treatment at 880 C. (Examples 7 and 14) directly to form glass ceramics with lithium disilicate as main crystal phase, as was established by X-ray diffraction tests. A final heat treatment at a temperature of from 860 to 950 C. (Examples 1, 3-4, 6-8, 10-12 and 14) finally resulted in the formation of glass ceramics with lithium disilicate as main crystal phase. By contrast, a final heat treatment at a temperature of only 820 to 840 C. (Examples 2, 5, 9 and 13) resulted in the formation of glass ceramics with lithium metasilicate as main crystal phase.

(6) The produced lithium disilicate glass ceramics had high fracture toughness values, measured as critical stress intensity factor K.sub.IC according to the SEVNB method, of more than 2 MPa.Math.m.sup.0.5 and in particular even at least 2.3 MPa.Math.m.sup.0.5.

(7) The biaxial strength GB was also high, at more than 400 MPa and up to more than 600 MPa. It was determined according to dental standard ISO 6872 (2008) on test pieces that were produced by machining of the respective lithium disilicate glass ceramic. A CEREC-InLab machine (Sirona, Bensheim) was used for the processing.

(8) They were also able to be applied by hot pressing as coatings in particular onto oxide ceramic restorations or metal restorations, e.g. in order to veneer them as desired.

(9) TABLE-US-00005 TABLE I Example 1 2 3 4 5 6 7 8 9 10 Composition wt.-% wt.-% wt.-% wt.-% wt.-% wt.-% wt.-% wt.-% wt.-% wt.-% SiO.sub.2 70.9 59.9 72.0 70.0 56.9 69.1 68.9 69.4 57.1 70.0 Li.sub.2O 14.8 18.0 15.0 14.5 15.5 14.4 14.9 14.5 16.0 14.5 Rb.sub.2O 7.7 7.7 6.3 6.1 7.7 6.0 3.7 6.1 7.7 6.1 Al.sub.2O.sub.3 3.4 3.5 3.4 3.2 3.4 3.3 3.0 3.2 3.5 3.2 P.sub.2O.sub.5 3.2 3.4 3.3 3.3 3.3 3.1 4.0 3.3 5.0 3.3 Na.sub.2O K.sub.2O 1.4 Cs.sub.2O MgO 0.3 0.3 CaO 3.0 Y.sub.2O.sub.3 La.sub.2O.sub.3 1.5 GeO.sub.2 8.0 0.8 ZrO.sub.2 5.0 0.4 2.0 0.9 1.4 0.8 2.0 0.4 CeO.sub.2 2.0 1.8 2.0 2.0 1.8 1.9 2.0 1.8 V.sub.2O.sub.5 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Tb.sub.4O.sub.7 0.3 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Er.sub.2O.sub.3 0.1 0.1 0.3 0.3 0.3 0.2 0.3 0.1 F 0.5 T.sub.g/ C. 471 476 468 468 465 471 467 477 447 468 T.sub.N/ C. 490 500 490 490 480 490 500 500 470 490 t.sub.N/min 10 30 10 10 10 10 10 10 10 10 T.sub.C/ C. 700 700 700 700 620 710 880 700 660 t.sub.C/min 20 20 20 20 40 20 30 20 30 Main Li.sub.2SiO.sub.3 Li.sub.2SiO.sub.3 Li.sub.2SiO.sub.3 Li.sub.2SiO.sub.3 Li.sub.2SiO.sub.3 Li.sub.2SiO.sub.3 Li.sub.2Si.sub.2O.sub.5 Li.sub.2SiO.sub.3 Li.sub.2SiO.sub.3 crystal phase Other Li.sub.2Si.sub.2O.sub.5 Li.sub.2Si.sub.2O.sub.5 Li.sub.2Si.sub.2O.sub.5 Li.sub.3PO.sub.4 Li.sub.2Si.sub.2O.sub.5 crystal phases T.sub.FC/ C. 880 820 880 870 830 860 870 820 t.sub.FC/min 7 20 7 7 7 7 7 10 T.sub.press/ C. 950 930 t.sub.Press/min 25 25 Main Li.sub.2Si.sub.2O.sub.5 Li.sub.2SiO.sub.3 Li.sub.2Si.sub.2O.sub.5 Li.sub.2Si.sub.2O.sub.5 Li.sub.2SiO.sub.3 Li.sub.2Si.sub.2O.sub.5 Li.sub.2Si.sub.2O.sub.5 Li.sub.2Si.sub.2O.sub.5 Li.sub.2SiO.sub.3 Li.sub.2Si.sub.2O.sub.5 crystal phase Other Li.sub.2SiO.sub.3 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Li.sub.2Si.sub.2O.sub.5 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 crystal Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Ca.sub.5(PO.sub.4).sub.3F phases L* 76.50 71.90 79.11 73.26 a* 3.37 9.34 6.32 8.40 b* 20.96 25.32 31.80 26.42 CR 89.85 84.79 68.55 84.29 CTE.sub.100-400 C./ 12.8 9.70 11.7 9.70 12.0 10.sup.6 .Math. K.sup.1 K.sub.IC/ MPa m.sup.0.5 .sub.B/MPa 687 576 Example 11 12 13 14 15 Composition wt.-% wt.-% wt.-% wt.-% wt.-% SiO.sub.2 69.1 69.4 63.3 68.6 69.5 Li.sub.2O 14.4 14.5 18.0 14.2 14.4 Rb.sub.2O 6.0 6.1 7.7 7.4 5.4 Al.sub.2O.sub.3 3.3 3.2 3.5 2.5 4.5 P.sub.2O.sub.5 3.1 3.3 3.4 3.4 3.4 Na.sub.2O K.sub.2O Cs.sub.2O 1.0 MgO 0.3 CaO Y.sub.2O.sub.3 3.0 La.sub.2O.sub.3 GeO.sub.2 ZrO.sub.2 0.9 0.8 1.5 1.8 CeO.sub.2 2.0 1.9 1.0 1.7 V.sub.2O.sub.5 0.1 0.1 0.1 0.1 Tb.sub.4O.sub.7 0.5 0.5 0.5 Er.sub.2O.sub.3 0.3 0.2 0.1 F T.sub.g/ C. 471 477 460 480 T.sub.N/ C. 490 500 480 500 t.sub.N/min 10 10 10 10 T.sub.C/ C. 600 880 t.sub.C/min 60 30 Main Li.sub.2SiO.sub.3 Li.sub.2Si.sub.2O.sub.5 crystal phase Other Li.sub.3PO.sub.4 crystal phases T.sub.FC/ C. 840 t.sub.FC/min 10 T.sub.press/ C. 940 930 950 t.sub.Press/min 25 25 25 Main Li.sub.2Si.sub.2O.sub.5 Li.sub.2Si.sub.2O.sub.5 Li.sub.2SiO.sub.3 Li.sub.2Si.sub.2O.sub.5 crystal phase Other Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 Li.sub.3PO.sub.4 crystal phases L* 71.18 81.27 a* 10.29 2.93 b* 32.91 24.26 CR 75.60 69.77 CTE.sub.100-400 C./ 12.4 9.6 10.sup.6 .Math. K.sup.1 K.sub.IC/ 2.30 MPa m.sup.0.5 .sub.B/MPa 411 L*, a*, b*: colour coordinates of the samples, determined according to DIN 5033 and DIN 6174 CR: contrast value as a measure of the translucence, determined according to BS 5612