Layered lithium disilicate glass-ceramic and preparation method thereof

文档序号：1931655 发布日期：2021-12-07 浏览：11次中文

阅读说明：本技术 一种层状二硅酸锂微晶玻璃及其制备方法 (Layered lithium disilicate glass-ceramic and preparation method thereof ) 是由张佩王贻然王可心王甜张效华施佩张彪张翠萍于 2021-10-11 设计创作，主要内容包括：本发明公开一种层状二硅酸锂微晶玻璃及其制备方法,将具有粗化二硅酸锂晶体的玻璃基体埋入与Li～(+)有反应活性的无机粉末中,进行高温处理得到层状二硅酸锂微晶玻璃,所述无机物粉末包括主料和辅料。本发明通过对二硅酸锂晶体形态和外观的有效控制,利用层状的二硅酸锂晶体对微晶玻璃实现同质增韧,进一步提高了材料的断裂韧性,且不影响最终制得的二硅酸锂微晶玻璃的透明度和外观。(The invention discloses a layered lithium disilicate glass-ceramic and a preparation method thereof, wherein a glass matrix with coarsened lithium disilicate crystals is embedded into the glass matrix and Li is added into the glass matrix + And (3) performing high-temperature treatment on the inorganic powder with reaction activity to obtain the layered lithium disilicate glass ceramics, wherein the inorganic powder comprises a main material and an auxiliary material. According to the invention, through effective control of the form and appearance of the lithium disilicate crystal, the layered lithium disilicate crystal is utilized to realize homogeneous toughening on the microcrystalline glass, so that the fracture toughness of the material is further improved, and the transparency and the appearance of the finally prepared lithium disilicate microcrystalline glass are not influenced.)

1. A method for preparing a layered lithium disilicate glass-ceramic is characterized in that a glass matrix with coarsened lithium disilicate crystals is embedded into Li⁺And (3) performing high-temperature treatment on the inorganic powder with reaction activity to obtain the layered lithium disilicate glass ceramics, wherein the inorganic powder comprises a main material and an auxiliary material.

2. The method for preparing a layered lithium disilicate glass-ceramic according to claim 1, wherein the main material comprises BN, AlN and SiO₂At least one of them.

3. The method for preparing a lithium disilicate glass-ceramic according to claim 2,

when BN, AlN and SiO₂When one of the inorganic powder is the main material, the proportion of the main material in the inorganic powder is 50-85 wt%;

when BN, AlN and SiO₂When any two of the inorganic powders are used as main materials, the proportion of the main materials in the inorganic powder is 40 wt% -90 wt%, the proportion of BN in the main materials is 55 wt% -70 wt%, and the proportion of AlN in the main materials is 45 wt% -75 wt%;

when BN, AlN and SiO₂When the inorganic powder is the main material, the proportion of the main material in the inorganic powder is 50 wt% -90 wt%, the proportion of BN in the main material is 35 wt% -55 wt%, and the proportion of AlN in the main material is 35 wt% -55 wt%.

4. The method for preparing a lithium disilicate glass-ceramic according to claim 1, characterized in thatThe auxiliary materials comprise MgO, CaO, ZnO and Al₂O₃At least one of them.

5. The method of claim 1, wherein the inorganic powder has a particle size of less than 400 mesh.

6. The method for preparing the lithium disilicate glass-ceramic according to claim 1, wherein the high temperature treatment is carried out by keeping the temperature at 895-925 ℃ for 6-48 h.

7. The method for preparing a layered lithium disilicate glass-ceramic according to claim 1, wherein after the glass matrix having coarsened lithium disilicate crystals is embedded in the inorganic powder, pressure is applied to the surface of the inorganic powder.

8. The method for preparing a lithium disilicate glass-ceramic according to claim 7, wherein the method for applying pressure is to place a smooth corundum plate on the inorganic powder.

9. The method for preparing a layered lithium disilicate glass-ceramic according to claim 1, wherein the glass substrate having coarsened lithium disilicate crystals is obtained by subjecting a transparent hard glass containing a lithium disilicate component to a two-step heat treatment.

10. The lithium layered disilicate glass-ceramic obtained by the production method according to any one of claims 1 to 9, characterized in that the lithium layered disilicate glass-ceramic has a fracture toughness of (4.12 ± 0.23) MPa-m^1/2～(4.67±0.16)MPa·m^1/2。

Technical Field

The invention belongs to the technical field of microcrystalline glass preparation processes, and particularly belongs to layered lithium disilicate microcrystalline glass and a preparation method thereof.

Background

The lithium disilicate glass ceramics is a novel inorganic non-metallic material, and the main application field is to manufacture denture restorations and carry out dental restoration at present. The artificial tooth prosthesis has the characteristics of safety, no toxicity, high mechanical property, stable physical and chemical properties and the like, and has semitransparent appearance, so that the prepared artificial tooth prosthesis has more vivid appearance, and is more attractive and elegant compared with the existing porcelain, all-porcelain, resin prosthesis and the like, and is more and more popular in the dental prosthesis market.

The lithium disilicate glass ceramics are mainly suitable for the currently developed chair-side CAD/CAM rapid processing and repairing system, have good processability and can be processed in net size, the bending strength of a finished product after subsequent heat treatment is more than 360MPa and higher than the strength standard (245MPa) of natural teeth, the requirement of ISO 6872 on the strength of dental glass ceramics is met, and the repaired teeth can bear the functional application of chewing, biting and the like. The mechanical property is closer to that of natural teeth, and the secondary damage to the natural teeth is small, so that the inorganic dental restoration material is expected to replace the existing zirconium oxide, garnet and other inorganic dental restoration materials. However, due to the inherent brittleness of the glass material, the prosthesis prepared from the material has a probability of edge breakage, crack damage and the like to a certain extent after being used for 4-8 years, and the use safety of a patient is seriously affected. Therefore, further improving the fracture toughness of lithium disilicate is a key objective of the current material research.

Addition of reinforcing phases to the glass is a common method of toughening glass, such as the addition of ZrO₂The particles can improve the toughness of the lithium disilicate glass ceramics. However, the addition of the reinforcing phase also forms a heterogeneous interface, which causes additional scattering of light, resulting in a significant decrease in transparency of the material, a whitish and deep color of the material, an unsightly appearance, a lack of vividness, and a great difference from natural teeth. Although the introduction of heterogeneous reinforcing phase improves the fracture toughness of the material, the introduction of heterogeneous reinforcing phase inevitably has negative influence on the optical performance, so that the material no longer has the functions of simulating and simulating natural teeth, deviates from the clinical use requirement of dental aesthetic restoration,cannot meet the basic requirements of patients on beauty, naturalness and simulation of the restoration body, and destroys the main performance advantages of the lithium disilicate glass ceramics.

In order to solve the contradiction between the toughening of the material and the transparency of the material, the self-toughening by using the lithium disilicate crystal is a good proposal, in the patent with the application number of 202010898794.3, the lithium disilicate glass ceramics with multi-scale crystal grains coexisting are prepared by repeated heat treatment, and the toughness is taken to reach (3.88 +/-0.11) - (4.24 +/-0.21) MPa.m^1/2Compared with the existing material, the improvement is about 25% -30%; however, the higher the toughness of the lithium disilicate glass ceramics, the longer the life, and the better the safety, and in order to further improve the toughness of the lithium disilicate glass ceramics, the improvement of the existing preparation method is needed.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides the layered lithium disilicate glass-ceramic and the preparation method thereof, by effectively controlling the form and the appearance of the lithium disilicate crystal, the layered lithium disilicate crystal is utilized to realize homogeneous toughening on the glass-ceramic, the fracture toughness of the material is further improved, and the transparency and the appearance of the finally prepared lithium disilicate glass-ceramic are not influenced.

In order to achieve the purpose, the invention provides the following technical scheme: a process for preparing the laminated microcrystal glass of lithium disilicate features that the glass substrate with coarsened crystal of lithium disilicate is embedded in Li⁺And (3) performing high-temperature treatment on the inorganic powder with reaction activity to obtain the layered lithium disilicate glass ceramics, wherein the inorganic powder comprises a main material and an auxiliary material.

Further, the main material comprises BN, AlN and SiO₂At least one of them.

Further, when BN, AlN and SiO₂When one of the inorganic powder is the main material, the proportion of the main material in the inorganic powder is 50-85 wt%;

when BN, AlN and SiO₂When any two of the above materials are main materials, the ratio of the main materials in the inorganic powder is 40 wt% -90 wt%, the ratio of BN in the main materials is 55 wt% -70 wt%, and the ratio of AlN in the main materials is 45 wt% >, up to e75wt％；

When BN, AlN and SiO₂When the inorganic powder is the main material, the proportion of the main material in the inorganic powder is 50 wt% -90 wt%, the proportion of BN in the main material is 35 wt% -55 wt%, and the proportion of AlN in the main material is 35 wt% -55 wt%.

Furthermore, the auxiliary materials comprise MgO, CaO, ZnO and Al₂O₃At least one of them.

Further, the particle size of the inorganic powder is less than 400 meshes.

Further, the high-temperature treatment is heat preservation for 6 to 48 hours at the temperature of between 895 and 925 ℃.

Furthermore, after the glass matrix with the coarsened lithium disilicate crystals is embedded into the inorganic powder, pressure is applied to the surface of the inorganic powder.

Further, the method for applying the pressure is to place a smooth corundum plate on the inorganic powder.

Further, the glass substrate having coarsened lithium disilicate crystals is obtained by subjecting a transparent hard glass containing a lithium disilicate component to a two-step heat treatment.

The invention also provides the layered lithium disilicate glass ceramics, and the fracture toughness performance of the layered lithium disilicate glass ceramics reaches (4.12 +/-0.23) MPa.m^1/2～(4.67±0.16)MPa·m^1/2。

Compared with the prior art, the invention has at least the following beneficial effects:

the invention discloses a method for preparing layered lithium disilicate glass ceramics, which is characterized in that the layered lithium disilicate glass ceramics are put into inorganic substance powder for heat treatment on the basis of the lithium disilicate glass ceramics, and Li in lithium disilicate crystals is adjusted⁺Thereby changing the morphology of the lithium disilicate crystals, increasing their size, and roughening their surface with distinct layer characteristics. The strength and toughness of the lithium disilicate glass ceramics are further improved through the consumption effects of the lamellar crystal grains on crack propagation, deflection, bridging and microcracks, the stability and reliability of the material use are ensured, heterogeneous phases are not introduced, the transparency and the appearance of the material are not influenced, and the material has the effects of simulating and simulating natureThe function of the teeth.

The lithium disilicate glass ceramics prepared by the invention can realize toughening completely by adjusting the shape of the lithium disilicate crystal, and no other reinforcing phase is introduced into the raw materials, so that no additional scattering impurity phase is caused to light, and the transparency and the appearance of the lithium disilicate glass ceramics can be ensured. Relevant experiments prove that the fracture toughness performance of the layered lithium disilicate glass ceramics disclosed by the invention reaches (4.12 +/-0.23) - (4.67 +/-0.16) MPa.m^1/2。

Drawings

FIG. 1 is a diffraction pattern of XRD crystal phase of lithium disilicate microcrystalline glass obtained in example 1 of the present invention after grain layering heat treatment;

FIG. 2 is an SEM image of the microstructure of the lithium disilicate glass ceramics obtained in example 1 of the present invention after being subjected to a grain-layering heat treatment, wherein (a) is an overall view and (b) is a partial enlarged view of (a);

FIG. 3 is a microstructure of crack propagation path of lithium disilicate glass ceramics in example 1 of the present invention. The deflection of the cracks and the breaking and extraction of the grains can be seen in the figures.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention provides a preparation method of lithium disilicate glass ceramics, which comprises the following steps:

1. the transparent hard glass containing lithium disilicate is used as glass base body, and is undergone the conventional heat treatment process to make the fine lithium disilicate crystal grow and precipitate in the glass base body.

2. And (3) preserving the temperature of the microcrystalline glass containing the refined lithium disilicate crystal at 955-1045 ℃ for 15-150 min, and heating to a temperature higher than the softening point temperature of the lithium disilicate crystal to partially re-melt and re-crystallize the lithium disilicate crystal, so as to obtain the glass substrate with the coarsened lithium disilicate crystal.

3. Embedding the glass matrix with coarsened lithium disilicate crystals into a square sagger filled with inorganic powder, wherein the powder needs to cover the glass matrix completely, and a corundum plate is used for covering the powder, and the powder is compacted by force, so that the lithium disilicate glass matrix can be fully attached and contacted with the powder. And (3) putting the sagger into a muffle furnace, and preserving heat for 6-48 hours at the temperature of 895-925 ℃. At this time, due to Li in the glass ceramics⁺High concentration, small volume, high activity, partial diffusion to embedded inorganic powder, SiO₂It remains in place because it is the basic structural constituent unit of the glass and crystal, thereby changing the chemical composition of the lithium disilicate crystal, and Li⁺The content of (A) is slightly reduced, so that the appearance of the crystal is obviously changed, and the crystal has an obvious layered structure. The fracture toughness performance of the lithium disilicate glass ceramics containing the lamellar crystals reaches (4.12 +/-0.23) - (4.67 +/-0.16) MPa.m^1/2。

Preferably, the inorganic powder for embedding in the step (3) is mixed with Li⁺Inorganic powder with certain reactivity;

preferably, the first and second liquid crystal materials are,the inorganic powder comprises main materials and auxiliary materials, the mass ratio sum of the main materials and the auxiliary materials in the inorganic powder is 100%, and the main materials comprise BN, AlN and SiO₂At least one of, the inorganic powder must be a main material; the auxiliary materials comprise MgO, CaO, ZnO and Al₂O₃Is at least one.

Preferably BN, AlN or SiO₂When one of the inorganic powder is used as a main material, the content of the main material in the inorganic powder is 50-85 wt%;

preferably, BN + AlN or BN + SiO₂、AlN+SiO₂When one of the compositions is the main material, the proportion of the main material in the inorganic powder is 40-90 wt%, the proportion of BN in the main material is 55-70 wt%, and the proportion of AlN in the main material is 45-75 wt%;

preferably, BN + AlN + SiO₂When the composition is the main material, the proportion of the main material in the inorganic powder is 50-90 wt%, the proportion of BN in the main material is 35-55 wt%, and the proportion of AlN in the main material is 35-55 wt%

Preferably, the inorganic embedding powder described in step (3) should have fine particles with a particle size of < 400 mesh in order to ensure sufficient contact between the powder and the glass.

Example 1

The invention prepares layered lithium disilicate glass ceramics, which comprises the steps of melting transparent hard glass containing lithium disilicate and heat treatment crystallization of the transparent hard glass containing lithium disilicate to obtain the lithium disilicate glass ceramics, and the method comprises the following steps:

(1) the transparent hard glass containing lithium disilicate is used as glass base body, and is undergone the conventional heat treatment process to make the fine lithium disilicate crystal grow and precipitate in the glass base body.

(2) The microcrystalline glass containing the refined lithium disilicate crystal is rapidly heated to 1010 ℃, the heating rate is 90 ℃/min, and then the temperature is kept for 65min, so that fine crystal grains are remelted and recrystallized, and the glass matrix of the coarsened lithium disilicate crystal is obtained.

(3) Heat treatment for layering lithium disilicate glass ceramics: embedding the obtained glass matrix of the coarsened lithium disilicate crystal into a square sagger filled with inorganic substance powder, wherein the powder needs to cover the glass matrix completely, and a corundum plate is used for covering the powder, and the powder is compacted by force, so that the lithium disilicate glass matrix can be fully attached and contacted with the powder.

The powder components and proportions are 50 wt% BN +30 wt% MgO +20 wt% CaO, all powder particle sizes are < 400 mesh. The sagger was placed in a muffle furnace and heated to 895 ℃ at 80 ℃/min and then held for 24 h.

At this stage, due to Li in the lithium disilicate glass ceramics₂High content of O, low viscosity at 895 deg.C, and Li⁺High ion concentration, small volume, high activity and strong diffusion capacity. By means of inorganic powders in contact with the glass-ceramics, part of Li⁺The ions can diffuse out into the powder, while the lithium disilicate crystal phase is due to Li⁺The reduction of ions causes morphological changes, forming distinct lamellar features. Meanwhile, due to long-time heat preservation, the lithium disilicate crystal also grows to a certain extent, and the overall size reaches 15-20 mu m. The surface of the layered lithium disilicate crystal is coarsened, the specific surface area is increased, the contact area with a glass substrate is increased, and the bonding strength is improved, so that better toughening effects such as obstruction, deflection, bridging, pulling-out and crack propagation energy consumption are formed on the crack propagation in the microcrystalline glass, and the fracture toughness of the microcrystalline glass is greatly improved.

The fracture toughness performance of the lamellar lithium disilicate glass ceramics prepared by three-step heat treatment reaches 4.19 +/-0.34 MPa.m^1/2。

Referring to FIG. 1, it can be seen from FIG. 1 that lithium metasilicate (Li) is precipitated from the lithium disilicate glass-ceramics after heat treatment at 650 ℃ and 830 ℃, respectively₂SiO₃) With lithium disilicate (Li)₂Si₂O₅) And (4) crystals.

Referring to FIG. 2, it can be seen from FIG. 2 that Li is contained in the lithium layered disilicate glass ceramics obtained in example 1₂Si₂O₅The crystal is changed into a crystal with the length of about 20 mu m and obvious lamellar characteristics, and has the effects of strengthening and toughening.

Referring to fig. 3, it can be seen from fig. 3 that when a crack propagates in the lithium layered disilicate glass ceramics prepared in example 1, the phenomena of deflection, interruption and transgranular fracture occur obviously, and the complication of the crack propagation path consumes more propagation energy, thus preventing the crack from further propagating, and improving the fracture toughness of the material. The lithium disilicate crystal grains with the layered characteristics have good reinforcing and toughening effects, and the strength and the toughness of the microcrystalline glass are greatly improved.

The fracture toughness of the method for preparing the layered lithium disilicate glass ceramics can reach 4.19 +/-0.34 MPa.m^1/2。

Example 2