FLUORESCENT GLASS CERAMIC WITH HIGH TRANSPARENCY AND PREPARATION METHOD AND USE THEREOF

Abstract

Provided are a fluorescent glass ceramic with high transparency and a preparation method and use thereof. The fluorescent glass ceramic includes the following raw materials by mass percentage: 63 wt % to 70 wt % of SiO.sub.2, 13 wt % to 16 wt % of Li.sub.2O, 1 wt % to 6 wt % of Al.sub.2O.sub.3, 1 wt % to 10 wt % of K.sub.2O, 2 wt % to 6 wt % of P.sub.2O.sub.5, 0.5 wt % to 3.5 wt % of CeO.sub.2, 0 wt % to 4 wt % of an additive, 1 wt % to 4 wt % of a lanthanide oxide with an atomic number of 59 to 71, and 0 wt % to 8 wt % of a colorant. The fluorescent glass ceramic has a lithium metasilicate crystal as a principal crystalline phase, and the lithium metasilicate crystal has a layered or plate-like structure and a grain size of 0.1 ?m to 1.5 ?m.

Claims

1. A fluorescent glass ceramic with high transparency, comprising the following raw materials by mass percentage: 63 wt % to 70 wt % of SiO.sub.2, 13 wt % to 16 wt % of Li.sub.2O, 1 wt % to 6 wt % of Al.sub.2O.sub.3, 1 wt % to 10 wt % of K.sub.2O, 2 wt % to 6 wt % of P.sub.2O.sub.5, 0.5 wt % to 3.5 wt % of CeO.sub.2, 0 wt % to 4 wt % of an additive, 1 wt % to 4 wt % of a lanthanide oxide with an atomic number of 59 to 71, and 0 wt % to 8 wt % of a colorant, wherein the fluorescent glass ceramic has a lithium metasilicate crystal as a principal crystalline phase; the lithium metasilicate crystal has a layered or plate-like structure; and the lithium metasilicate crystal has a grain size of 0.1 ?m to 1.5 ?m.

2. The fluorescent glass ceramic of claim 1, comprising the following raw materials by mass percentage: 64 wt % to 66 wt % of the SiO.sub.2, 14 wt % to 15 wt % of the Li.sub.2O, 2 wt % to 4 wt % of the Al.sub.2O.sub.3, 2 wt % to 5 wt % of the K.sub.2O, 3 wt % to 4 wt % of the P.sub.2O.sub.5, 1.5 wt % to 3.0 wt % of the CeO.sub.2, 1 wt % to 3 wt % of the additive, 1.5 wt % to 3.0 wt % of the lanthanide oxide with the atomic number of 59 to 71, and 1 wt % to 4 wt % of the colorant.

3. The fluorescent glass ceramic of claim 1, wherein the additive comprises at least one selected from the group consisting of a monovalent metal oxide and a divalent metal oxide.

4. The fluorescent glass ceramic of claim 3, wherein the monovalent metal oxide comprises at least one selected from the group consisting of Na.sub.2O, Rb.sub.2O, and Cs.sub.2O; and the divalent metal oxide comprises at least one selected from the group consisting of MgO, SrO, ZnO, and CaO.

5. The fluorescent glass ceramic of claim 1, wherein the lanthanide oxide with the atomic number of 59 to 71 comprises at least one selected from the group consisting of Nd.sub.2O.sub.3, Tb.sub.2O.sub.3, Pr.sub.6O.sub.11, Eu.sub.2O.sub.3, and Er.sub.2O.sub.3.

6. The fluorescent glass ceramic of claim 1, wherein the colorant comprises at least one selected from the group consisting of TiO.sub.2, CuO, MnO, and SeO.sub.2.

7. The fluorescent glass ceramic of claim 1, wherein a 1-mm-thick sample of the fluorescent glass ceramic has an optical transmittance of 40% to 90% at 550 nm.

8. A method for preparing the fluorescent glass ceramic of claim 1, comprising: (1) mixing the raw materials of the fluorescent glass ceramic according to a proportion to obtain a mixture, and subjecting the mixture to primary melting and water quenching in sequence to obtain a glass slag; (2) subjecting the glass slag obtained in step (1) to secondary melting and a forming annealing treatment in sequence to obtain a first glass matrix; or subjecting the glass slag obtained in step (1) to grinding, dry pressing, and vacuum sintering in sequence to obtain a second glass matrix; and (3) subjecting the first glass matrix or the second glass matrix obtained in step (2) to a first heat treatment and a second heat treatment in sequence to obtain the fluorescent glass ceramic with high transparency.

9. The method of claim 8, wherein in step (1), the primary melting is conducted at a temperature of 1,300? C. to 1,600? C.; and in step (1), the primary melting is conducted for 1 h to 6 h.

10. The method of claim 8, wherein in step (2), the secondary melting is conducted at a temperature of 1,300? C. to 1,600? C.; and in step (2), the secondary melting is conducted for 1 h to 6 h.

11. The method of claim 8, wherein in step (2), the forming annealing treatment comprises: pouring a base glass liquid obtained after the secondary melting into a first mold preheated to a temperature of 200? C. to 500? C. and subjecting the base glass liquid to annealing.

12. The method of claim 8, wherein the forming annealing treatment is conducted for 0.5 h to 24 h; and the method further comprises cooling the first glass matrix to ambient temperature after the forming annealing treatment.

13. The method of claim 8, wherein in step (2), a glass powder with a particle size of 0.2 ?m to 50 ?m is obtained after the grinding.

14. The method of claim 8, wherein in step (2), the dry pressing comprises: subjecting the glass powder obtained after the grinding to dry pressing at a pressure of 5 MPa to 50 MPa in a second mold to obtain the biscuit.

15. The method of claim 8, wherein in step (2), the vacuum sintering is conducted at a vacuum degree of 100 Pa to 3,000 Pa; in step (2), the vacuum sintering is conducted at a temperature of 900? C. to 1,200? C.; and in step (2), the vacuum sintering is conducted for 100 min to 240 min.

16. The method of claim 8, wherein in step (3), the first heat treatment is conducted at a temperature of 450? C. to 580? C.; and in step (3), the first heat treatment is conducted for 1 h to 48 h.

17. The method of claim 8, wherein in step (3), the second heat treatment is conducted at a temperature of 600? C. to 700? C.; and in step (3), the second heat treatment is conducted for 10 min to 240 min.

18. Use of the fluorescent glass ceramic with high transparency of claim 1 in a chair-side restoration system.

19. The fluorescent glass ceramic of claim 2, wherein the additive comprises at least one selected from the group consisting of a monovalent metal oxide and a divalent metal oxide.

20. The fluorescent glass ceramic of claim 2, wherein the lanthanide oxide with the atomic number of 59 to 71 comprises at least one selected from the group consisting of Nd.sub.2O.sub.3, Tb.sub.2O.sub.3, Pr.sub.6O.sub.11, Eu.sub.2O.sub.3, and Er.sub.2O.sub.3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG. 1 is a diagram showing fluorescence spectrum of the fluorescent glass ceramic obtained in Example 1 of the present disclosure;

[0055] FIG. 2 shows the microscopic topography (by scanning electron microscope, SEM) of the fluorescent glass ceramic obtained in Example 1 of the present disclosure;

[0056] FIG. 3 shows an X-ray diffraction (XRD) pattern of the fluorescent glass ceramic obtain in Example 1 of the present disclosure; and

[0057] FIG. 4 shows a transmittance curve of the fluorescent glass ceramic obtained in Example 1 of the present disclosure at a visible light ranging from 370 nm to 900 nm.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] In order to better illustrate the present disclosure and facilitate understanding of the technical solutions of the present disclosure, the present disclosure will be further described in detail below. However, the following examples are only simple examples of the present disclosure, and do not represent or limit the protection scope of the present disclosure. The protection scope of the present disclosure is subject to the claims.

[0059] The raw materials of the fluorescent glass ceramics prepared in the following examples are shown in Table 1, where the content of each component is in mass percentage.

TABLE-US-00001 TABLE 1 Raw material formulations of Examples 1 to 4 Examples No. Example 1 Example 2 Example 3 Example 4 SiO.sub.2 65 66 64 65 Li.sub.2O 14.6 15.6 14.4 15.5 K.sub.2O 3.6 3.8 4.2 4.7 Al.sub.2O.sub.3 3.8 3.6 3.8 3.0 P.sub.2O.sub.5 3.5 3.8 3.8 3.4 CeO.sub.2 2.8 3.2 2.8 2.8 SrO 1.6 1.8 2.0 1.0 MgO 1.4 1.0 1.6 1.5 TiO.sub.2 2.05 1.2 1.8 1.8 MnO 1.65 1.6 1.3

[0060] The following are typical but non-limiting examples of the present disclosure:

Example 1

[0061] In this example, a method for preparing a fluorescent glass ceramic with high transparency was provided, where raw materials of the fluorescent glass ceramic were shown in Table 1.

[0062] The method for preparing the fluorescent glass ceramic was conducted as follows: [0063] (1) Raw materials of the fluorescent glass ceramic were mixed evenly according to the proportion, and a resulting mixed material was placed in a crucible and then subjected to primary melting at 1,450? C. for 6 h, such that the raw materials were evenly distributed and the bubbles were escaped completely. The resulting melted material was subjected to water quenching to obtain a glass slag. [0064] (2) The glass slag obtained in step (1) was placed in the crucible and then subjected to secondary melting at 1,450? C. for 6 h to obtain a glass liquid.

[0065] The glass liquid was poured into a first mold at 350? C. for molding, annealed for 1.5 h, and then naturally cooled to ambient temperature to obtain a first glass matrix. [0066] (3) The first glass matrix obtained in step (2) was heated at 500? C. for 90 min, and then at 660? C. for 120 min to obtain the fluorescent glass ceramic with high transparency.

[0067] The fluorescent glass ceramic obtained in this example was characterized. The ceramic has a fluorescence spectrum shown in FIG. 1, a microscopic topography shown in FIG. 2, an XRD pattern shown in FIG. 3, and a transmittance curve at visible light ranging from 370 nm to 900 nm shown in FIG. 4.

[0068] It can be seen from FIG. 1 that under an excitation wavelength of 366 nm, an emission spectrum shows a maximum width value at 430 nm. It is mainly attributed to the fact that Ce.sup.3+ ions are prone to the interaction of 4f to 5d electric dipoles, and the fluorescence displayed could be perceived as a blue-white fluorescence as a whole by human eyes.

[0069] It can be seen from FIG. 2 that the sample has a plate-like microscopic morphology.

[0070] It can be seen from FIG. 3 that the product has lithium metasilicate (Li.sub.2SiO.sub.3) as a principal crystalline phase.

[0071] It can be seen from FIG. 4 that a 1-mm-thick sample of the lithium metasilicate-based glass ceramic has an optical transmittance of 74.43% at 550 nm.

Example 2

[0072] In this example, a method for preparing a fluorescent glass ceramic with high transparency was provided, where raw materials of the fluorescent glass ceramic were shown in Table 1.

[0073] The method for preparing the fluorescent glass ceramic was conducted as follows: [0074] (1) Raw materials of the fluorescent glass ceramic were mixed evenly according to the proportion, and a resulting mixed material was placed in a crucible and then subjected to primary melting at 1,550? C. for 3 h, such that the raw materials were evenly distributed and the bubbles were escaped completely. The resulting melted material was subjected to water quenching to obtain a glass slag. [0075] (2) The glass slag obtained in step (1) was ground into a glass powder with a particle size of 20 ?m, placed in a second mold and subjected to dry pressing at 10 MPa to obtain a biscuit. The biscuit was further placed in a vacuum sintering furnace and then subjected to sintering at a vacuum degree of 2,000 Pa and 1,100? C. for 120 min to obtain a second glass matrix. [0076] (3) The second glass matrix obtained in step (2) was heated at 530? C. for 100 min, and then at 640? C. for 140 min to obtain the fluorescent glass ceramic with high transparency.

Example 3

[0077] In this example, a method for preparing a fluorescent glass ceramic with high transparency was provided, where raw materials of the fluorescent glass ceramic were shown in Table 1.

[0078] The method for preparing the fluorescent glass ceramic was conducted as follows: [0079] (1) Raw materials of the fluorescent glass ceramic were mixed evenly according to the proportion, and a resulting mixed material was placed in a crucible and then subjected to primary melting at 1,550? C. for 4 h, such that the raw materials were evenly distributed and the bubbles were escaped completely. The resulting melted material was subjected to water quenching to obtain a glass slag. [0080] (2) The glass slag obtained in step (1) was placed in the crucible and then subjected to secondary melting at 1,550? C. for 4 h to obtain a glass liquid.

[0081] The glass liquid was poured into a first mold at 350? C. for molding, annealed for 2 h, and then naturally cooled to ambient temperature to obtain a first glass matrix. [0082] (3) The first glass matrix obtained in step (2) was heated at 570? C. for 150 min, and then at 650? C. for 120 min to obtain the fluorescent glass ceramic with high transparency.

Example 4

[0083] In this example, a method for preparing a fluorescent glass ceramic with high transparency was provided, where raw materials of the fluorescent glass ceramic were shown in Table 1.

[0084] The method for preparing the fluorescent glass ceramic was conducted as follows: [0085] (1) Raw materials of the fluorescent glass ceramic were mixed evenly according to the proportion, and a resulting mixed material was placed in a crucible and then subjected to primary melting at 1,550? C. for 5 h, such that the raw materials were evenly distributed and the bubbles were escaped completely. The resulting melted material was subjected to water quenching to obtain a glass slag. [0086] (2) The glass slag obtained in step (1) was ground into a glass powder with a particle size of 40 ?m, placed in a second mold and subjected to dry pressing at 25 MPa to obtain a biscuit. The biscuit was further placed in a vacuum sintering furnace and then subjected to sintering at a vacuum degree of 2,400 Pa and 1,150? C. for 160 min to obtain a second glass matrix. [0087] (3) The second glass matrix obtained in step (2) was heated at 560? C. for 160 min, and then at 630? C. for 150 min to obtain the fluorescent glass ceramic with high transparency.

Example 5

[0088] In this example, a method for preparing a glass ceramic was provided, where raw materials of the glass ceramic are the same as those of the fluorescent glass ceramic in Example 1.

[0089] The method was conducted as described in Example 1, except that: in step (3), only a first heat treatment was conducted without a second heat treatment.

Example 6

[0090] In this example, a method for preparing a glass ceramic was provided, where raw materials of the glass ceramic are the same as those of the fluorescent glass ceramic in Example 1.

[0091] The method was conducted as described in Example 1, except that: in step (3), the second heat treatment was conducted at 750? C.

[0092] Phase analysis was conducted on the glass ceramics obtained in Examples 1 to 6 and processing properties thereof were tested. The results are shown in Table 2.

TABLE-US-00002 Table 2 Processability data of the glass ceramics prepared in Examples 1 to 6 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 T.sub.1 (? C.) 500 530 570 560 500 500 t.sub.1 (min) 90 100 150 160 90 90 T.sub.2 (? C.) 660 640 650 630 750 t.sub.2 (min) 120 140 120 150 120 Crystal phase 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 after A small crystallization amount of Li.sub.2Si.sub.2O.sub.5 Crystal form Plate-like Plate-like Layered Layered Layered Bar-shaped Processibility No Minor No No Chipping Severe chipping chipping chipping chipping chipping

[0093] T.sub.1 and t.sub.1 are the temperature and time of the first heat treatment, respectively; and T.sub.2 and t.sub.2 are the temperature and time of the second heat treatment, respectively.

[0094] Three-point bending strength, hardness, grain size after crystallization, transmittance at 550 nm, and fluorescence properties of the glass ceramics obtained in Examples 1 to 6 were each determined according to the following methods. The results are shown in Table 3. [0095] (1) Three-point bending strength: according to international standard ISO6872:2008, 15 samples were tested, and an average value of obtained three-point bending strength values was calculated. [0096] (2) Vickers hardness: according to international standard ISO14705:2008, 15 sets of data were tested using a Vickers hardness tester to apply a load of 1 kilogram force (1 kgf), and then calculated to obtain an average value of the Vickers hardness of the samples. [0097] (3) Transmittance: a test sample was tested at a wavelength of 370 nm to 900 nm using a spectrophotometer, where the test sample had a thickness of 1 mm. [0098] (4) Fluorescence properties: the glass ceramics each were cut into a size of 13 mm?15 mm?2 mm, and then tested at an excitation wavelength of 366 nm, and a scanning range of 375 nm to 700 nm.

TABLE-US-00003 TABLE 3 Performance data of the glass ceramics prepared in Examples 1 to 6 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Three-point bending 127 115 130 126 95 200 strength (MPa) Hardness (GPa) 5.70 5.90 5.50 5.40 5.40 5.50 Grain size after 0.6 0.8 1.0 0.5 0.4 1.2 crystallization (?m) Transmittance (%, at 74.43 70.12 64.65 84.23 86.43 38 550 nm) Fluorescent glass Blue-white Blue Strong Blue-white Weak Weak ceramic blue-white blue-white blue-white

[0099] As can be seen from Example 1 in Tables 2 and 3, since a large number of plate-like lithium metasilicate crystals are distributed in the glass matrix, the prepared glass ceramic is extremely easy to process and has no chipping. The high glass phase content and the similar refractive index also enable the prepared glass ceramic with a transmittance of up to 74.43% at the wavelength of 550 nm. In addition, the ceramic exhibits a three-point bending strength of 127 MPa and a hardness of 5.70 GPa, providing a guarantee for subsequent processing and grinding. Moreover, the glass ceramic could display a blue-white fluorescence effect under ultraviolet light, showing excellent aesthetic properties.

[0100] As can be seen from Example 2 in Tables 2 and 3, since a large number of plate-like lithium metasilicate crystals are distributed in the glass matrix, the prepared glass ceramic is extremely easy to process and has only minor chipping. The prepared glass ceramic has a transmittance of up to 70.12% at the wavelength of 550 nm. In addition, the ceramic exhibits a three-point bending strength of 115 MPa and a hardness of 5.90 GPa. Moreover, the glass ceramic could display a blue fluorescence effect under ultraviolet light, showing excellent aesthetic properties.

[0101] As can be seen from Example 3 in Tables 2 and 3, since a large number of layered lithium metasilicate crystals are distributed in the glass matrix, the prepared glass ceramic is extremely easy to process and has no chipping. The high glass phase content and the similar refractive index also enable the prepared glass ceramic with a transmittance of up to 64.65% at the wavelength of 550 nm. In addition, the ceramic exhibits a three-point bending strength of 130 MPa and a hardness of 5.50 GPa, providing a guarantee for subsequent processing and grinding. Moreover, the glass ceramic could display a strong blue-white fluorescence effect under ultraviolet light, showing excellent aesthetic properties.

[0102] As can be seen from Example 4 in Tables 2 and 3, since a large number of layered lithium metasilicate crystals are distributed in the glass matrix, the prepared glass ceramic is extremely easy to process and has only minor chipping. The prepared glass ceramic has a transmittance of up to 84.23% at the wavelength of 550 nm. In addition, the ceramic exhibits a three-point bending strength of 126 MPa and a hardness of 5.40 GPa. Moreover, the glass ceramic could display a blue-white fluorescence effect under ultraviolet light, showing excellent aesthetic properties.

[0103] As can be seen from Example 5 in Table 2 and Table 3, since only the first heat treatment is conducted without the second heat treatment, the three-point bending strength is 95 MPa, the grain size after crystallization is 0.4 ?m, and the transmittance is as high as 86.43%. Moreover, the glass ceramic could display a weak blue-white fluorescence effect under ultraviolet light, which is difficult to show excellent aesthetic properties.

[0104] As can be seen from Example 6 in Table 2 and Table 3, due to an increased temperature of the second heat treatment, the three-point bending strength is 200 MPa, the grain size after crystallization is 1.2 ?m, and the transmittance is reduced to 38%. In addition, the higher second heat treatment temperature also tends to allow the Li.sub.2SiO.sub.3 crystal to continue growing to form a bar-shaped Li.sub.2Si.sub.2O.sub.5 crystal, resulting in serious chipping and reduced transmittance during processing, which affects the aesthetic properties.

[0105] Combining the above examples, it can be seen that the fluorescent glass ceramic of the present disclosure does not include pentavalent/hexavalent metal oxides; by optimizing a composition ratio and optimizing a heat treatment process during the preparation process, the processability, high transparency, and fluorescence properties of the lithium metasilicate-based glass ceramic are greatly improved; and the ceramic has a transmittance of not less than 64.65% at a wavelength of 550 nm.

[0106] The present disclosure describes detailed products and methods through the above examples, but is not limited to the above detailed products and methods; that is, the above description does not mean that the present disclosure must rely on the above detailed products and methods to be implemented. Those skilled in the art should understand that any improvement and equivalent replacement to the present disclosure, addition of auxiliary ingredients, selection of specific ways and the like all fall within the scope of protection and disclosure of the present disclosure.