WO2019100622A1 - Nano-structure yttrium aluminum garnet based transparent ceramic material, preparation method therefor and uses thereof - Google Patents

Abstract

A nano-structure YAG based transparent ceramic material, a preparation method therefor, and uses thereof. The transparent ceramic is of a nanocomposite structure consisting of YAG and Al2O3; and the grain sizes of both YAG crystalline phase and Al2O3 crystalline phase are less than 100 nm. The YAG based transparent ceramic is prepared by carrying out heat treatment to an amorphous bulk glass precursor; during the heat treatment, a part of aluminum oxide in the bulk glass precursor reacts with yttrium oxide to generate a YAG crystalline phase; and the generated YAG crystalline phase and the remaining aluminum oxide crystalline phase construct a nanocomposite structure. The YAG based transparent ceramic material has a hardness and an elastic modulus comparable even superior to those of a YAG single crystal, is optically transparent within a waveband range from visible light to middle infrared light, and has excellent photoluminescence performance after being doped with luminous active ions.

Description

Nanostructured yttrium aluminum garnet based transparent ceramic material, preparation method and use thereof Technical field

The invention belongs to the technical field of transparent ceramic materials, and relates to a nanostructure yttrium aluminum garnet-based transparent ceramic material, preparation and use thereof.

Background technique

Y ₃ Al ₅ O ₁₂ (YAG) transparent ceramic is an important photoluminescent matrix material with excellent mechanical properties, thermal properties, high temperature stability and optical properties in laser, fluorescence and scintillation. The field has important applications. From the current report, the preparation of YAG transparent ceramics mainly uses powder sintering technology. However, in order to achieve high transparency of YAG ceramics, high purity of raw materials, fine crystal grains and good dispersibility are required, and special sintering means is required to completely eliminate pores in ceramics, thereby achieving full densification of ceramics and extremely thin grain boundaries. Therefore, the YAG transparent ceramics are prepared by the powder sintering method, which has extremely severe requirements on raw materials, equipment, molding and sintering processes, and is difficult to meet the requirements of commercial production. In addition, the long-term sintering process of the powder is accompanied by the growth of YAG crystal grains, so the YAG transparent ceramic prepared by the powder sintering method is often a microcrystalline ceramic, and it is difficult to obtain a nanostructure. According to the Hall-petch formula and the Rayleigh scattering formula, nanostructured ceramic materials tend to achieve better mechanical and optical properties.

Crystallizing the bulk glass material at a suitable temperature to obtain a transparent ceramic (ie, amorphous crystallization method) is a new idea for preparing YAG transparent ceramics, which can effectively avoid the disadvantages of the preparation conditions such as the powder sintering method. . However, there has been no report on the successful preparation of YAG transparent ceramics by amorphous crystallization. The main reason is that if the bulk glass material with YAG component is directly heat treated, YAG grains will grow rapidly during crystallization, accompanied by a large number of pores and microcracks, resulting in complete ceramic material obtained after crystallization. Destruction. Strictly control the crystallization time and crystallization temperature, so that the amorphous YAG phase can only be analyzed, or a large amount of the third component (such as La ₂ O ₃ , SiO _{2 ,} etc.) can be effectively inhibited from crystallization. Excessive growth of YAG grains during the process yields a YAG-based transparent glass ceramic material. However, the obtained transparent glass ceramic material contains a large amount of amorphous phase, and the content of the YAG phase in the whole transparent ceramic is low (generally less than 20% by weight), and the mechanical properties (such as hardness) of the prepared transparent ceramic (glass ceramic) material are obtained. , strength, etc.), thermodynamic properties (such as thermal conductivity, etc.) and optical properties (photoluminescence quantum efficiency, etc.) are much lower than YAG transparent ceramics prepared by powder sintering. Prolong the crystallization time, increase the crystallization temperature or reduce the addition amount of the third component in the glass component to increase the content of YAG phase in the ceramic, but in the crystallization process, as the content of the YAG crystal phase increases, the crystal of YAG The particles are also inevitably grown to sub-micron or even micron scale, and the prepared ceramic material becomes translucent or completely opaque.

Zhou Shengming and other scholars of Shanghai Institute of Optics and Mechanics also reported a YAG-based complex phase in the invention patent "a composite phase transparent ceramic for white LED fluorescence conversion and its preparation method" (Application No.: 2015100678616) and related articles. Transparent ceramic material. However, the transparent ceramic material is produced by a conventional powder sintering method in which YAG and Al ₂ O ₃ grains are inevitably excessively grown during sintering. Therefore, the ceramic material prepared is a micron ceramic, and the light transmittance is also affected, and only translucent can be achieved.

Summary of the invention

In view of the problems of the prior art, an object of the present invention is to provide a novel nanostructured YAG-based transparent ceramic material, a preparation method thereof and use thereof. The YAG-based transparent ceramic material of the present invention is optically transparent in the visible to mid-infrared region, and has a very high transmittance in the visible to infrared range. The theoretical maximum transmittance of the YAG single crystal is 85%, and the YAG-based transparent of the present invention is transparent. The transmittance of ceramic materials is more than 60% of the theoretical maximum transmittance of YAG single crystals, and has important application prospects in the field of optical lenses. The YAG-based transparent ceramic material exhibits high hardness and elastic modulus comparable to or even surpassed the YAG single crystal, and has important application prospects in the field of high-grade jewelry and decorations.

In order to achieve the above object, the present invention adopts the following technical solutions:

In a first aspect, the present invention provides a YAG-based transparent ceramic material comprising a nanocomplex structure composed of a YAG crystal phase and an Al ₂ O ₃ crystal phase, and a YAG crystal phase and Al ₂ O ₃ The crystallite size of the crystal phase is less than 100 nm.

In the YAG-based transparent ceramic material of the present invention, the grain size of the YAG crystal phase is less than 100 nm, for example, 95 nm, 90 nm, 88 nm, 85 nm, 82.5 nm, 80 nm, 77 nm, 75 nm, 72 nm, 70 nm, 65 nm, 62.5 nm, 60 nm, 55 nm, 50 nm, 45 nm, 40 nm, 35 nm, 30 nm, 25 nm, 20 nm or 10 nm, and the like.

In the YAG-based transparent ceramic material of the present invention, the crystal grain size of the Al ₂ O ₃ crystal phase is less than 100 nm, for example, 90 nm, 85 nm, 80 nm, 77 nm, 75 nm, 70 nm, 65 nm, 60 nm, 55 nm, 50 nm, 45 nm, 40 nm, 35 nm. , 30 nm, 25 nm or 20 nm, and the like.

In the YAG-based transparent ceramic of the present invention, the grain size of the YAG crystal phase and the Al ₂ O ₃ crystal phase are all less than 100 nm, which is a necessary feature, and only when the condition is satisfied, the prepared transparent ceramic material can be ensured in the visible light region. through.

The YAG-based transparent ceramic material of the present invention is a fully crystallized ceramic material in which a YAG crystal phase and an Al ₂ O ₃ crystal phase constitute a multiphase nanostructure.

The YAG-based transparent ceramic material of the present invention is a nanostructured YAG-based transparent ceramic material.

The YAG base transparent ceramic of the present invention is optically transparent in the visible to mid-infrared region, and has a transmittance in the visible to infrared range of more than 60% of the theoretical value of the YAG single crystal.

The term "comprising" as used in the present invention means that in addition to the components, it may include other components which impart different characteristics to the YAG-based ceramic material. In addition, the "include" of the present invention may also be replaced by a closed "for" or "consisting of".

In the present invention, yttrium aluminum garnet (Y ₃ Al ₅ O ₁₂ , YAG) is a composite oxide formed by the reaction of Y ₂ O ₃ and Al ₂ O ₃ , which belongs to a cubic crystal system and has a garnet structure. The composition of yttrium aluminum garnet is: Y ₂ O ₃ and Al ₂ O ₃ .

In the nano-complex structure of the present invention, Al ₂ O ₃ has two sources, one is Al ₂ O ₃ in yttrium aluminum garnet, and the other is an independently existing Al ₂ O ₃ crystal phase; the nano-complex structure of the present invention Among them, Y ₂ O ₃ has only one source, namely Y ₂ O ₃ in yttrium aluminum garnet.

Preferably, the molar percentage of the Al ₂ O ₃ , Y ₂ O ₃ and other metal oxides is 70 mol% to 80 mol%, 20 mol% to 30 mol%, respectively, based on 100 mol% of the total molar amount of the nanocomplex structure. And 0-10% mol, the other metals are metals different from Al and Y.

In this preferred embodiment, the molar percentage of Al ₂ O ₃ is from 70 mol% to 80 mol%, for example, 70 mol%, 72 mol%, 75 mol%, 76 mol%, 77 mol%, 78 mol% or 80 mol%, and the like.

In this preferred embodiment, the molar percentage of Y ₂ O ₃ is from 20 mol% to 30 mol%, for example, 20 mol%, 22 mol%, 24 mol%, 25 mol%, 26 mol%, 27 mol%, 29 mol% or 30 mol%, and the like.

In this preferred embodiment, the molar percentage of other metal oxides (the other metals are metals different from Al and Y) is 0-10 mol%, such as 0, 0.5 mol%, 1 mol%, 2 mol%, 3 mol%, 4 mol. %, 5 mol%, 6 mol%, 7 mol%, 8 mol% or 10 mol%, and the like. "The molar percentage of other metal oxides is 0" means that no other metal oxides are present.

Preferably, other metal oxides include cerium oxide (CeO ₂ ), cerium oxide (Dy ₂ O ₃ ), cerium oxide (Er ₂ O ₃ ), cerium oxide (Eu ₂ O ₃ ), cerium oxide (Gd ₂ O ₃ ) , cerium oxide (Ho ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), lanthanum oxide (Lu ₂ O ₃ ), cerium oxide (Nd ₂ O ₃ ), cerium oxide (Pr ₆ O ₁₁ ), cerium oxide (Sm) ₂ O ₃ ), yttrium oxide (Tb ₂ O ₃ ), yttrium oxide (Th ₄ O ₇ ), yttrium oxide (Tm ₂ O ₃ ), yttrium oxide (Yb ₂ O ₃ ), chromium oxide (CrO ₂ ) or silicon oxide Any one or a combination of at least two of (SiO ₂ ), but not limited to the oxides listed above, other oxides commonly used in the art which can achieve the same effect can also be used in the present invention.

As a preferred technical solution of the YAG-based transparent ceramic material of the present invention, the YAG crystal phase accounts for 60% by weight to 86% by weight of the YAG-based transparent ceramic material, for example, 60 wt%, 62 wt%, 65 wt%, and 67.5 wt%. 70 wt%, 72 wt%, 75 wt%, 77 wt%, 78 wt%, 80 wt%, 81 wt%, 83 wt%, 85 wt% or 86 wt%, and the like.

Preferably, the Al ₂ O ₃ crystal phase accounts for 14 wt% to 40 wt% of the YAG-based transparent ceramic material, for example, 14 wt%, 15 wt%, 17 wt%, 18 wt%, 20 wt%, 22.5 wt%, 25 wt%. 26 wt%, 27 wt%, 28.5 wt%, 30 wt%, 32 wt%, 35 wt%, 37 wt% or 40 wt%, and the like.

As a preferred technical solution of the YAG-based transparent ceramic material of the present invention, the YAG-based transparent ceramic material is a doped YAG-based transparent ceramic material.

Preferably, the doping ions in the doped YAG-based transparent ceramic material are Ce ³⁺ , Nd ³⁺ , La ³⁺ , Si ⁴⁺ , Lu ³⁺ , Ga ³⁺ , Eu ³⁺ , Gd ³⁺ Any one or at least two of Ho ³⁺ , Er ³⁺ , Dy ³⁺ , Sm ³⁺ , Tb ³⁺ , Cr ³⁺ , Tm ³⁺ , Th ³⁺ , Pr ³⁺ or Yb ³⁺ Combinations, but not limited to the above-mentioned dopant ions, other activated ions commonly used in the art can also be used in the present invention, and the YAG-based transparent ceramics obtained after doping exhibit excellent photoluminescence properties.

Preferably, the doping ions are doped at the Y ³⁺ position of the YAG crystal phase, and the molar percentage of the doping ions is 100% of the total molar amount of the doping ions and Y ³⁺ That is, the doping concentration) is 0.02 mol% to 10 mol%, for example, 0.02 mol%, 0.1 mol%, 0.5 mol%, 1 mol%, 1.5 mol%, 2 mol%, 3 mol%, 3.5 mol%, 5 mol%, 6 mol% 7 mol%, 7.5 mol%, 8 mol%, 9 mol%, 9.5 mol% or 10 mol%, and the like.

In the present invention, after the YAG-based transparent ceramic material is doped with 0.02 mol% to 10 mol% of Ce ³⁺ , the obtained Ce ³⁺ doped YAG-based transparent ceramic material can emit under the excitation of light of 330-350 nm or 400-500 nm. Yellow-green light with a wavelength of 480-650 nm is emitted. It is indicated that the Ce ³⁺ doped YAG-based transparent ceramic material can be well combined with the blue light emitted by the GaN blue substrate to produce white light, which can be applied to the field of white LED illumination.

In the present invention, the YAG-based transparent ceramic material is doped with 0.02 mol% to 10 mol% of Nd ³⁺ , and the obtained Nd ³⁺ doped YAG-based transparent ceramic material has high transmittance, and the Nd ³⁺ doping is 1 mm thick. The YAG-based transparent ceramic material has a transmittance of more than 80% at a wavelength of 1064 nm, and has an important application prospect in the field of solid-state lasers.

In a second aspect, the present invention provides a method of preparing a YAG-based transparent ceramic material according to the first aspect, the method comprising the steps of:

The bulk glass precursor is heat-treated to obtain a YAG-based transparent ceramic material, and the molar percentage of Al ₂ O ₃ is more than 70 mol% based on 100% of the total molar composition of the raw material composition of the bulk glass precursor.

After a large number of experiments, the YAG-based ceramic material obtained after crystallization can maintain high optical transparency when only Al ₂ O ₃ content in the raw material composition is higher than 70 mol%. When the composition has Al ₂ O ₃ less than 70 mol%, The YAG-based ceramic material obtained after crystallization becomes completely opaque.

In the method of the present invention, the above definition of the molar content of Al ₂ O ₃ is related to the performance of the YAG-based transparent ceramic product, and only when the Al ₂ O ₃ content is higher than 70 mol%, in the YAG-based ceramic material obtained after crystallization. The grain size of the YAG crystal phase and the Al ₂ O ₃ crystal phase can both be less than 100 nm.

In the method of the present invention, the bulk glass precursor includes yttrium oxide (Y ₂ O ₃ ) and aluminum oxide (Al ₂ O ₃ ) and optionally other metal oxides, and a part of the aluminum oxide reacts with cerium oxide during heat treatment. A YAG crystal phase is obtained, and a part of the alumina crystal phase remains, and the obtained YAG crystal phase and the remaining alumina crystal phase constitute a multiphase nanostructure.

The bulk glass precursor of the present invention is a bulk amorphous material.

In the present invention, the "raw material composition of the bulk glass precursor" means a raw material used for preparing a bulk glass precursor.

In the method of the present invention, a bulk glass precursor is prepared by using a raw material having a specific Al ₂ O ₃ content, followed by heat treatment, and amorphous crystallization to obtain a nanostructured YAG-based transparent ceramic material.

The method of the invention solves the problem that the high-quality nano-powder is used as a raw material in the preparation of the YAG transparent ceramic material by the conventional powder sintering method, the preparation condition is harsh, and the nanostructure is difficult to obtain.

In the method of the present invention, the Y ₂ O ₃ raw material, the Al ₂ O ₃ raw material and the optional other metal oxide raw materials used may be analytically pure powder or high-purity powder, and the purity is 95%-100. The powder of % can satisfy the requirements, and the YAG-based transparent ceramic of the present invention is prepared.

As a preferred technical solution of the method of the present invention, the grain size in the bulk glass precursor is on the order of nanometers, preferably less than 100 nm, for example, 95 nm, 90 nm, 80 nm, 75 nm, 70 nm, 60 nm, 55 nm, 50 nm, 40 nm. 35 nm, 25 nm, 20 nm, 15 nm, 10 nm or 5 nm, and the like.

Preferably, the temperature of the heat treatment is from 900 ° C to 1200 ° C, for example, 900 ° C, 950 ° C, 1000 ° C, 1050 ° C, 1100 ° C, 1150 ° C, 1175 ° C or 1200 ° C.

Preferably, the heat treatment time is 5 min-12 h, for example 5 min, 15 min, 20 min, 30 min, 45 min, 1 h, 2 h, 3.5 h, 4 h, 5.5 h, 7 h, 9 h, 10 h, 10.5 h, 11 h or 12 h, etc. .

Preferably, the heat treatment adopts any one of a primary crystallization treatment method or a step crystallization treatment method.

Wherein, the primary crystallization treatment method is: heat treatment at 900 ° C - 1200 ° C for 5 min - 12 h; the step crystallization treatment method is: first heat treatment at 900 ° C - 980 ° C for 5 min - 4 h, and then at 980 ° C - 1200 ° C Heat treatment for 5min-8h.

In the present invention, a method of preparing a glass block precursor includes, but is not limited to, a containerless solidification method, a viscous sintering method of an amorphous powder, a quenching method, a casting method, and the like.

As a preferred technical solution of the method of the present invention, the bulk glass precursor is prepared by a containerless solidification method, and the containerless solidification method comprises the following steps:

(1) mixing Y ₂ O ₃ and Al ₂ O ₃ and optionally other metal oxide powders, and then pressing into a bulk material;

(2) Stabilizing the bulk material in the air and heating the bulk material to complete melting;

(3) cooling and solidifying the sample obtained by melting in a suspended state to obtain a bulk glass precursor;

Wherein the other metals are metals different from Al and Y.

The "powder of Y ₂ O ₃ , Al ₂ O ₃ and optionally other metal oxides" according to the present invention actually comprises two parallel technical solutions, namely, scheme 1: Y ₂ O ₃ , Al ₂ A powder of O ₃ and other metal oxides; Scheme 2: a powder of Y ₂ O ₃ and Al ₂ O ₃ .

Preferably, the other metal oxides in the step (1) include cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, Any one or a combination of at least two of cerium oxide, cerium oxide, cerium oxide, chromium oxide or silicon oxide.

Preferably, the molar percentage of the Y ₂ O ₃ is 20 mol% to 30 mol%, for example, 20 mol%, 21 mol%, 22 mol%, 22.5 mol%, 23.5 mol%, based on 100 mol% of the total molar amount of the oxide powder. 25 mol%, 26 mol%, 27 mol%, 28 mol%, 29 mol% or 30 mol%, and the like.

Preferably, the molar percentage of the Al ₂ O ₃ is from 70 mol% to 80 mol%, for example, 70 mol%, 72 mol%, 73 mol%, 74 mol%, 75 mol%, 76.5, based on 100 mol% of the total molar amount of the oxide powder. Mol%, 77 mol%, 78 mol% or 80 mol%, and the like.

Preferably, the molar percentage of the other metal oxide is 0-mol 10%, for example, 0, 0.05 mol%, 0.1 mol%, 0.2 mol%, 0.5 mol, based on 100 mol% of the total molar amount of the oxide powder. %, 1 mol%, 1.5 mol%, 2 mol%, 2.5 mol%, 3 mol%, 4 mol%, 4.5 mol%, 5 mol%, 6 mol%, 6.5 mol%, 7 mol%, 8 mol%, 8.5 mol%, 9 mol% or 10 mol % and the like, wherein "the molar percentage of other metal oxides is 0" means that other metal oxides are not included in the oxide powder.

Preferably, the manner of stably suspending the bulk material in the air in the step (2) includes any one of a gas suspension, an ultrasonic suspension, an electrostatic suspension or an electromagnetic suspension, or a combination of at least two.

Preferably, when the step (2) uses a gas suspension to stably suspend the bulk material in the air, the gas for stably suspending the bulk material is any one of O ₂ , N ₂ , He, Ar or air. The flow rate of the gas is from 10 ml/min to 5000 ml/min, for example, 10 ml/min, 50 ml/min, 100 ml/min, 150 ml/min, 200 ml/min, 350 ml/min, 500 ml/min, 700 ml/min, 850 ml/min. 1000 ml/min, 1300 ml/min, 1600 ml/min, 2000 ml/min, 2200 ml/min, 2700 ml/min, 3000 ml/min, 3500 ml/min, 4000 ml/min or 5000 ml/min, and the like.

Preferably, the heating in the step (3) is any one of laser heating or induction heating or a combination of at least two.

Preferably, the cooling rate during cooling according to step (3) is 100K/s-300K/s, for example, 100K/s, 125K/s, 150K/s, 170K/s, 200K/s, 220K/s, 230K. /s, 245K/s, 260K/s, 280K/s, 290K/s or 300K/s, etc.

Preferably, the resulting bulk glass precursor has a size of from 0.1 mm to 10 mm.

As a preferred technical solution of the method of the present invention, in the process of preparing the bulk glass precursor by the containerless solidification method, the following step (1) is performed before the step (2) after the step (1): the bulk material is It is sintered at 800 ° C - 1500 ° C in an air or oxygen atmosphere and broken into small pieces. The purpose of the thermal insulation sintering step is to increase the strength of the bulk material, and further breaking into small pieces is advantageous for improving the effect of the subsequent step (2) stable suspension and heating and melting.

In the preferred embodiment, the temperature of the thermal insulation sintering of the step (1)' is 800 ° C - 1500 ° C, for example, 800 ° C, 850 ° C, 900 ° C, 1000 ° C, 1100 ° C, 1150 ° C, 1200 ° C, 1300 ° C, 1350. °C, 1400 ° C or 1500 ° C, etc.

Preferably, in the step (1)', the time of the heat preservation sintering is 2h-15h, for example, 2h, 3.5h, 5h, 8h, 10h, 12h, 13h, 14h or 15h.

Preferably, in the step (1)', the mass of the broken pieces is from 0.1 mg to 1000 mg.

Preferably, the method further comprises performing step (2)' before step (3) after step (2): maintaining the molten state for 10 s to 10 minutes to uniformly mix the components in the melt.

As a preferred technical solution of the method of the present invention, the bulk glass precursor is prepared by a viscous sintering method of an amorphous powder, and the viscous sintering method of the amorphous powder comprises the following steps:

(A) preparing a glass powder from a powder of Y ₂ O ₃ , Al ₂ O ₃ and optionally other metal oxides;

(B) Then hot press sintering was carried out in the glass dynamics window temperature range to obtain a bulk glass precursor.

Preferably, the other metal oxides in the step (A) include cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, Any one or a combination of at least two of cerium oxide, cerium oxide, cerium oxide, chromium oxide or silicon oxide.

Preferably, the molar percentage of the Y ₂ O ₃ is from 20 mol% to 30 mol%, based on 100 mol% of the total molar amount of the oxide powder.

Preferably, the molar percentage of the Al ₂ O ₃ is from 70 mol% to 80 mol%, based on 100 mol% of the total molar amount of the oxide powder.

Preferably, the molar percentage of the other metal oxide is from 0 to 10 mol% based on 100 mol% of the total molar amount of the oxide powder.

Preferably, the glass powder of the step (A) has a particle size of 10 nm to 100 μm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 45 nm, 50 nm, 70 nm, 85 nm, 100 nm, 200 nm, 300 nm, 350 nm, 450 nm, 500 nm, 650 nm. 750 nm, 900 nm, 1 μm, 3 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 90 μm or 100 μm, etc., preferably 30 nm to 50 nm or 20 μm to 50 μm.

Preferably, the method of preparing the glass powder in the step (A) includes, but is not limited to, any one of a sol-gel method, a co-precipitation method, a flame spray method, or a container-free solidification method.

Preferably, the glass dynamics window temperature of step (B) is from 800 ° C to 1100 ° C, for example, 800 ° C, 850 ° C, 900 ° C, 950 ° C, 975 ° C, 1000 ° C, 1050 ° C or 1100 ° C, and the like.

Preferably, in the hot press sintering in the step (B), the pressure is 10 MPa to 5 GPa, for example, 10 MPa, 30 MPa, 50 MPa, 75 MPa, 100 MPa, 150 MPa, 200 MPa, 265 MPa, 300 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 850 MPa, 1 GPa, 1.2 GPa, 1.5 GPa, 2 GPa, 2.3 GPa, 2.5 GPa, 3 GPa, 3.5 GPa, 4 GPa, 4.5 GPa or 5 GPa, and the like.

Preferably, in the hot press sintering in the step (B), the hot press sintering time is 10 min to 12 h, for example, 10 min, 30 min, 45 min, 1 h, 2.5 h, 3 h, 5 h, 6 h, 8 h, 10 h, 11 h or 12 h. Wait.

The bulk glass precursor of the present invention can also be prepared by a conventional smelting method including the following steps: using Y ₂ O ₃ , Al ₂ O ₃ and optionally other metal oxide powders as raw materials. After heating and melting, it is naturally cooled to obtain a bulk glass precursor;

Preferably, the other metal oxides include cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, oxidation. Any one or a combination of at least two of cerium, cerium oxide, chromium oxide or silicon oxide.

Preferably, the molar percentage of the Y ₂ O ₃ is from 20 mol% to 30 mol%, based on 100 mol% of the total molar amount of the oxide powder.

Preferably, the molar percentage of the Al ₂ O ₃ is from 70 mol% to 80 mol%, based on 100 mol% of the total molar amount of the oxide powder.

Preferably, the molar percentage of the other metal oxide is from 0 to 10 mol% based on 100 mol% of the total molar amount of the oxide powder.

In a third aspect, the present invention provides the use of the YAG-based transparent ceramic material according to the first aspect, wherein the YAG-based transparent ceramic of the present invention has high transmittance in the mid-infrared region of visible light, and the theoretical maximum transmission of the YAG single crystal. The rate is 85%, the transmittance of the YAG-based transparent ceramic material of the present invention is 60%-88% of the theoretical maximum transmittance of the YAG single crystal; the nanoindentation hardness is as high as 13GPa-25GPa; and the Young's modulus is 160GPa- 350GPa, which is comparable to or better than the hardness and elastic modulus of YAG single crystal, has a good application prospect in the fields of laser, fluorescence, scintillation, optical lens, crafts (especially high-end crafts) and jewelry.

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

(1) The present invention heat-treats an amorphous bulk glass precursor to cause a part of alumina in the bulk glass precursor to react with yttrium oxide to form a YAG crystal phase, the resulting YAG crystal phase and the remaining alumina crystal phase. Together, they constitute a multiphase nanostructure, thereby obtaining a YAG-based transparent ceramic.

(2) The YAG-based transparent ceramic of the present invention exhibits hardness and elastic modulus comparable to or better than that of the YAG single crystal, and is optically transparent in the visible to mid-infrared ^region , and is doped with light-activated ions such as Ce ³⁺ and Nd ³⁺ . It can then exhibit excellent photoluminescence properties.

(3) The YAG-based transparent ceramic of the invention has broad application prospects in the fields of laser, fluorescence, scintillation, optical lens, high-end crafts and jewelry.

DRAWINGS

1 is a schematic view of a suspension device used for preparing a bulk glass precursor according to Embodiment 1 of the present invention, wherein 1 represents a laser heating system, 2 represents a temperature measurement system, 3 represents a camera system, 4 represents a carrier gas flow system, and 41 represents a nozzle. 42 represents a gas flow conduit, 43 represents a gas flow meter, 5 carrier gases, and 6 represents a sample.

2 is an optical photograph of the nanostructured YAG-based transparent ceramic material of Example 13.

3 is a graph showing the transmittance of the YAG-based transparent ceramic material of Example 13 in the visible to mid-infrared region.

4 is a photograph showing the microstructure of the YAG-based transparent ceramic material of Example 13.

Figure 5 is a photograph of a Ce ³⁺ doped YAG-based transparent ceramic material of Example 21, in which the transparent ceramic material is bright yellow.

6 is an excitation emission line of a Ce ³⁺ doped YAG-based transparent ceramic material of Example 21.

Detailed ways

The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

Example 1-12: Preparation of nanostructured YAG-based transparent ceramic material by aeroelastic suspension-free container solidification-amorphous crystallization method

First, the bulk glass precursor material is prepared by a pneumatic suspension container-free solidification method, and the specific method is as follows:

(1) According to the raw material ratio (molar percentage) of Examples 1 to 12 listed in Table 1, the Y ₂ O ₃ raw material, the Al ₂ O ₃ raw material, and optionally other metal oxide raw materials Re ₂ are respectively weighed. O ₃ (wherein Re ₂ O ₃ is a rare earth oxide, specifically: cerium oxide (CeO ₂ ), cerium oxide (Dy ₂ O ₃ ), cerium oxide (Er ₂ O ₃ ), cerium oxide (Eu ₂ O ₃ ) , yttrium oxide (Gd ₂ O ₃ ), yttrium oxide (Ho ₂ O ₃ ), lanthanum oxide (La ₂ O ₃ ), lanthanum oxide (Lu ₂ O ₃ ), yttrium oxide (Nd ₂ O ₃ ), yttrium oxide (Pr) ₆ O ₁₁ ), strontium oxide (Sm ₂ O ₃ ), strontium oxide (Tb ₂ O ₃ ), strontium oxide (Th ₄ O ₇ ), strontium oxide (Tm ₂ O ₃ ) or yttrium oxide (Yb ₂ O ₃ ) Any one or a combination of at least two), the raw material is a high-purity (99.99%) powder or an analytically pure (98%) powder, and after thorough mixing, the powder is pressed into a cylindrical block by a tableting machine;

(2) The block material is placed in an electric resistance furnace, sintered at 1500 ° C for 2 h, and then the sample is cut into cubes having a mass of 2 mg to 1000 mg by a cutting tool;

(3) placing the cube described in step (2) on the nozzle of the pneumatic suspension device (see FIG. 1 for a schematic view of the device);

(4) Turn on the CO ₂ laser, adjust the laser power to 80W, completely melt the sample, select high purity O ₂ as the carrier gas, open the air flow switch, adjust the gas flow to make the sample stably suspended, and keep the molten state for 30s;

(5) Turn off the laser to rapidly cool and solidify the droplets in a suspended state to obtain a bulk amorphous precursor material. The bulk glass precursor material is a bulk amorphous precursor, and the whole solidification process can pass the temperature measuring system 2 and The camera system 3 observes changes in temperature and morphology of the sample 6 during solidification.

Then, a nanostructured YAG-based transparent ceramic material is prepared by an amorphous crystallization method, and the specific method is as follows:

The bulk amorphous precursor is placed in an electric resistance furnace, and the heat treatment system is: heat treatment at 950 ° C, 960 ° C, 1010 ° C, 1100 ° C, 1150 ° C and 1200 ° C for 2 h, to obtain a nanostructured YAG-based transparent ceramic material. See Table 2 for the composition of the YAG-based transparent ceramic materials of the respective examples.

In the YAG-based transparent ceramic material obtained in Examples 1-12, the grain size of the YAG crystal phase was from 30 nm to 80 nm, and the grain size of the Al ₂ O ₃ crystal phase was from 5 nm to 80 nm.

Example 13

Unless the heat treatment system is heat-treated at 1100 ° C for 2 h during the preparation of the crystallization method, the other preparation methods and conditions are the same as in Example 3, and a nanostructured YAG-based transparent ceramic material is obtained.

Figure 2 is an optical photograph of the YAG-based transparent ceramic material of the present Example 13.

3 is a transmittance curve of the YAG-based transparent ceramic material of the present embodiment 13 in the visible to mid-infrared region. It can be seen from the figure that the sample is highly transparent in the visible to mid-infrared region, and the highest transmittance reaches the YAG single. The theoretical maximum transmittance (85%) of the crystal and the infrared cutoff wavelength of up to 6.5 μm.

4 is a photomicrograph of the microstructure of the nanostructured YAG-based transparent ceramic material of the embodiment 13. As can be seen from the figure, in the YAG-based transparent ceramic material of the present embodiment, the average grain size of the YAG crystal phase is 30 nm. The particle distribution is uniform and the Al ₂ O ₃ grain size is less than 30 nm.

Example 14-20: YAG-based transparent ceramic material prepared by flame spray quenching-viscosity sintering-amorphous crystallization method

First, the micro glass powder is prepared by flame spray quenching method, and the specific method is as follows:

(1) Synthesis of crystalline raw material powder: According to the raw material ratio (molar percentage) of Examples 14-20 listed in Table 3, Y ₂ O ₃ raw material, Al ₂ O ₃ raw material and optional CeO were respectively weighed. ₂ raw materials, raw materials are high purity (99.99%) powder or analytically pure (98%) powder, after thorough mixing, heated to 1500 ° C in air and held for 2 hours, the ball was ball milled to 1 μm - 2 μm;

(2) granulating the powder described in the step (1): preparing PVA, PAA, n-octanol and solid content of 0.5%, 0.5%, 0.5% and 65% granulation slurry, respectively, by spray granulation The slurry is spray granulated, wherein the hot air inlet and the slurry outlet temperature are respectively selected to be 190 ° C and 100 ° C, and the gas flow rate and the slurry flow rate are selected to be 660 L / h and 10 ml / min, respectively;

(3) The pellet obtained after granulation is uniformly supplied from the acetylene flame axially with Ar as a carrier gas, and the flame is directed to cold water, the pellet feeding speed is 10 g/min, and the flow rate of acetylene is 15 L/ respectively. Min and 20L/min.

The micron glass spheres are formed as follows: the pellets are rapidly heated in an acetylene flame to be completely melted and sprayed into cold water to rapidly cool and solidify into a glass powder.

Using this method, a pure phase micro glass sphere having a composition of 1 μm to 100 μm was obtained.

Then, the bulk glass precursor material is prepared by a viscous sintering method, and the specific method is as follows:

(1) The micron-sized glass powder prepared by the above flame spray-quenching method was placed in an ink mill having a diameter of 10 mm.

(2) The graphite mold containing the glass powder was placed in a hot press sintering furnace, and the temperature was raised to 880 ° C at a heating rate of 5 k/min to carry out hot press sintering for 2 hours to obtain a bulk glass precursor material. The pressure was selected to be 50 MPa, and the pressurization was completed 30 minutes before the temperature was raised to 880 °C.

Finally, the nanostructured YAG-based transparent ceramic material is obtained by amorphous crystallization method. The specific method is as follows:

The bulk glass precursor material obtained above was placed in an electric resistance furnace, heated to 960 ° C for 2 h, heated to 1100 ° C for 2 h, and finally cooled with the furnace to finally obtain YAG groups with different Ce ³⁺ doping concentrations. For transparent ceramics, the composition of the YAG-based transparent ceramic materials of the respective examples is shown in Table 4.

In the YAG-based transparent ceramic material obtained in Examples 14-20, the grain size of the YAG crystal phase is from 15 nm to 80 nm, and the grain size of the Al ₂ O ₃ crystal phase is from 10 nm to 50 nm.

Example 21

The preparation method and conditions were the same as in Example 14 except that the molar ratio of Y ₂ O ₃ was 25.98 mol% and the molar percentage of CeO ₂ was 0.02 mol%.

In the YAG-based transparent ceramic material obtained in the present embodiment, the grain size of the YAG crystal phase is 80-100 nm, and the grain size of the crystal phase of Al ₂ O ₃ is 50-100 nm.

Figure 5 is a photograph of the YAG-based transparent ceramic material of Example 21. As can be seen from the figure, the prepared nano-ceramic is highly transparent, and the transparent ceramic material in the picture is bright yellow.

6 is an excitation emission line of a Ce ³⁺ doped YAG-based transparent ceramic material of Example 21. As can be seen from the figure, the prepared transparent ceramic sample has two broad excitation peaks, and the peak center wavelength is 340 nm. And 460nm. The sample can obtain a broad emission peak with a peak wavelength of 528 nm under excitation light of both 340 nm and 460 nm, and the wavelength ranges from 480 nm to 560 nm. The intensity of the emitted light at 340 nm excitation is weak, and the intensity of the emitted light at 460 nm is higher. Since the blue-green light of the band can be well combined with the yellow light emitted by GaN to produce white light, the prepared transparent nano ceramic material has an important application prospect in the field of white LED illumination.

Examples 22-28: Preparation of nanostructured YAG-based transparent ceramic materials by amorphous crystallization.

(1) Synthetic crystalline raw material powder: According to the raw material ratio (molar percentage) of Examples 22-28 listed in Table 5, Y ₂ O ₃ raw material, Al ₂ O ₃ raw material and SiO ₂ raw material were respectively weighed. The starting material was a high purity (99.99%) powder or an analytically pure (98%) powder which was thoroughly mixed in a mortar.

(2) The above mixed raw materials are placed in a platinum crucible, heated in an electric resistance furnace to 1800 ° C for 10 min, then heated to 1850 ° C for 10 min, cooled to 1800 ° C for 30 min, and then naturally cooled to obtain a bulk glass. Precursor material.

(3) The bulk glass precursor material obtained above was heat-treated at 1000 ° C for 3 h, and the glass material was crystallized to obtain a nanostructured YAG-based transparent ceramic material. The composition of the YAG-based transparent ceramic material of each example is shown in Table 6.

In the YAG-based transparent ceramic material obtained in Examples 22-28, the YAG crystal phase has a crystallite size of 5 nm to 30 nm, and the Al ₂ O ₃ crystal phase has a crystal grain size of 5 nm to 30 nm.

Table 1 Raw material ratio (molar percentage) of Examples 1-12

Note: Re ₂ O _{3 in the} table is rare earth oxide, specifically: cerium oxide (CeO ₂ ), cerium oxide (Dy ₂ O ₃ ), cerium oxide (Er ₂ O ₃ ), cerium oxide (Eu ₂ O ₃ ), Antimony oxide (Gd ₂ O ₃ ), antimony oxide (Ho ₂ O ₃ ), antimony oxide (La ₂ O ₃ ), antimony oxide (Lu ₂ O ₃ ), antimony oxide (Nd ₂ O ₃ ), antimony oxide (Pr ₆₎ O ₁₁ ), strontium oxide (Sm ₂ O ₃ ), strontium oxide (Tb ₂ O ₃ ), strontium oxide (Th ₄ O ₇ ), strontium oxide (Tm ₂ O ₃ ) or yttrium oxide (Yb ₂ O ₃ ) Any one or a combination of at least two.

Table 2 Composition of YAG-based transparent ceramics obtained in Examples 1-12 (mass percentage)

Table 3 The raw material ratio (molar percentage) of Examples 14-20

Table 4 Composition of YAG-based transparent ceramics obtained in Examples 14-20 (mass percentage)

Table 5: Raw material ratio (molar percentage) of Examples 22-28

Table 6 Compositions of YAG-based transparent ceramics obtained in Examples 22-28 (mass percentage)

The Applicant declares that the present invention is described by the above-described embodiments, but the present invention is not limited to the above detailed methods, that is, it does not mean that the present invention must be implemented by the above detailed methods. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitution of the various materials of the products of the present invention, addition of auxiliary components, selection of specific means, and the like, are all within the scope of the present invention.

Claims (11)

1. A nanostructured yttrium aluminum garnet YAG-based transparent ceramic material, characterized in that the YAG-based transparent ceramic material has a nanocomplex structure composed of a YAG crystal phase and an Al ₂ O ₃ crystal phase, and a YAG crystal phase and Al The grain size of the ₂ O ₃ crystal phase is less than 100 nm.
2. The YAG-based transparent ceramic material according to claim 1, wherein the Al ₂ O ₃ , Y ₂ O ₃ and other metal oxides account for a total molar amount of the nanocomplex structure of 100 mol%. The percentages are 70 mol% to 80 mol%, 20 mol% to 30 mol%, and 0 to 10 mol%, respectively, and the other metals are metals different from Al and Y.
3. The YAG-based transparent ceramic material according to claim 2, wherein the other metal oxides include cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide. Any one or a combination of at least two of cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, chromium oxide or silicon oxide.
4. The YAG-based transparent ceramic material according to any one of claims 1 to 3, wherein the YAG crystal phase accounts for 60% by weight to 86% by weight of the YAG-based transparent ceramic material;

   Preferably, the Al ₂ O ₃ crystal phase accounts for 14% by weight to 40% by weight of the YAG-based transparent ceramic material.
5. The YAG-based transparent ceramic material according to any one of claims 1 to 4, wherein the YAG-based transparent ceramic material is a doped YAG-based transparent ceramic material;

   Preferably, the doping ions in the doped YAG-based transparent ceramic material are C _e ³⁺ , Nd ³⁺ , La ³⁺ , Si ⁴⁺ , Lu ³⁺ , Ga ³⁺ , Eu ³⁺ , Gd ³ Any one or at least two of ⁺ , Ho ³⁺ , Er ³⁺ , Dy ³⁺ , Sm ³⁺ , Tb ³⁺ , Cr ³⁺ , Tm ³⁺ , Th ³⁺ , Pr ³⁺ or Yb ³⁺ The combination;

   Preferably, the doping ions are doped at the Y ³⁺ position of the YAG crystal phase, and the total molar amount of the doping ions and Y ³⁺ is 100%, and the molar percentage of the doping ions is 0.02 mol% to 10 mol%.
6. A method of producing a YAG-based transparent ceramic material according to any one of claims 1 to 5, wherein the method comprises:

   The bulk glass precursor is heat-treated to obtain a YAG-based transparent ceramic material, and the molar percentage of Al ₂ O ₃ is more than 70 mol% based on 100% of the total molar composition of the raw material composition of the bulk glass precursor.
7. The method according to claim 6, wherein the grain size in the bulk glass precursor is on the order of nanometers, preferably less than 100 nm;

   Preferably, the temperature of the heat treatment is between 900 ° C and 1200 ° C;

   Preferably, the heat treatment time is 5min-12h;

   Preferably, the heat treatment adopts any one of a primary crystallization treatment method or a step crystallization treatment method.

   The primary crystallization treatment method is: heat treatment at 900 ° C - 1200 ° C for 5 min - 12 h;

   The step crystallization treatment method is: first heat treatment at 900 ° C - 980 ° C for 5 min - 4 h, and then heat treatment at 980 ° C - 1200 ° C for 5 min - 8 h.
8. The method according to claim 6 or 7, wherein the bulk glass precursor is prepared by a containerless solidification method, and the containerless solidification method comprises the following steps:

   (1) mixing Y ₂ O ₃ , Al ₂ O ₃ and optionally other metal oxide powders, and then pressing into a bulk material;

   (2) Stabilizing the bulk material in the air and heating the bulk material to complete melting;

   (3) cooling and solidifying the sample obtained by melting in a suspended state to obtain a bulk glass precursor;

   Wherein the other metal is a metal different from Al and Y;

   Preferably, the other metal oxides include cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, oxidation. Any one or a combination of at least two of cerium, cerium oxide, chromium oxide or silicon oxide;

   Preferably, the molar percentage of the Y ₂ O ₃ is 20 mol% to 30 mol%, based on 100 mol% of the total molar amount of the oxide powder;

   Preferably, the molar percentage of the Al ₂ O ₃ is from 70 mol% to 80 mol%, based on 100 mol% of the total molar amount of the oxide powder;

   Preferably, the molar percentage of the other metal oxide is 0-10 mol%, based on 100 mol% of the total molar amount of the oxide powder;

   Preferably, the manner of stably suspending the bulk material in the air in the step (2) includes any one of a gas suspension, an ultrasonic suspension, an electrostatic suspension or an electromagnetic suspension, or a combination of at least two;

   Preferably, when the step (2) uses a gas suspension to stably suspend the bulk material in the air, the gas for stably suspending the bulk material is any one of O ₂ , N ₂ , He, Ar or air. The flow rate of the gas is from 10ml/min to 5000ml/min;

   Preferably, the heating in the step (3) is any one of laser heating or induction heating or a combination of at least two;

   Preferably, the cooling rate at the time of cooling according to step (3) is 100K/s-300K/s;

   Preferably, the obtained bulk glass precursor has a size of 0.1 mm to 10 mm;

   Preferably, the method further comprises the following step (1) before the step (2) after the step (1): the block raw material is sintered at 800 ° C to 1500 ° C in an air or oxygen atmosphere, and is broken into small pieces. Piece;

   Preferably, in step (1)', the time of heat preservation sintering is 2h-15h;

   Preferably, in step (1)', the mass of the broken pieces is from 0.1 mg to 1000 mg;

   Preferably, the method further comprises performing step (2)' prior to step (3) after step (2): maintaining in the molten state for 10 s to 10 min.
9. The method according to claim 8, wherein said bulk glass precursor is prepared by a viscous sintering method of an amorphous powder, and said viscous sintering method of said amorphous powder comprises the steps of:

   (A) preparing a glass powder from a powder of Y ₂ O ₃ , Al ₂ O ₃ and optionally other metal oxides;

   (B) then performing hot press sintering in a glass dynamics window temperature range to obtain a bulk glass precursor;

   Preferably, the other metal oxides in the step (A) include cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, Any one or a combination of at least two of cerium oxide, cerium oxide, cerium oxide, chromium oxide or silicon oxide;

   Preferably, the molar percentage of the Y ₂ O ₃ is 20 mol% to 30 mol%, based on 100 mol% of the total molar amount of the oxide powder;

   Preferably, the molar percentage of the Al ₂ O ₃ is from 70 mol% to 80 mol%, based on 100 mol% of the total molar amount of the oxide powder;

   Preferably, the molar percentage of the other metal oxide is 0-10 mol%, based on 100 mol% of the total molar amount of the oxide powder;

   Preferably, the glass powder of the step (A) has a particle size of 10 nm to 100 μm, preferably 30 nm to 50 nm or 20 μm to 50 μm;

   Preferably, the method for preparing the glass powder in the step (A) is any one of a sol gel method, a coprecipitation method, a flame spray method or a containerless solidification method;

   Preferably, the glass dynamics window temperature of step (B) is from 800 ° C to 1100 ° C;

   Preferably, in the hot press sintering of step (B), the pressure is 10 MPa -5 GPa;

   Preferably, in the hot press sintering in the step (B), the hot press sintering time is from 10 min to 12 h.
10. The method according to claim 8 or 9, wherein the bulk glass precursor is prepared by a melt casting method, the melt casting method comprising the steps of: Y ₂ O ₃ , Al ₂ O ₃ and optionally The powder of other metal oxide is used as a raw material, and is naturally cooled by heating and melting to obtain a bulk glass precursor;

    Preferably, the other metal oxides include cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, cerium oxide, oxidation. Any one or a combination of at least two of cerium, cerium oxide, chromium oxide or silicon oxide;

    Preferably, the molar percentage of the Y ₂ O ₃ is 20 mol% to 30 mol%, based on 100 mol% of the total molar amount of the oxide powder;

    Preferably, the molar percentage of the Al ₂ O ₃ is from 70 mol% to 80 mol%, based on 100 mol% of the total molar amount of the oxide powder;

    Preferably, the molar percentage of the other metal oxide is from 0 to 10 mol% based on 100 mol% of the total molar amount of the oxide powder.
11. Use of the YAG-based transparent ceramic material according to any one of claims 1 to 5, characterized in that the YAG-based transparent ceramic material is used in the fields of laser, fluorescence, scintillation, optical lenses, handicrafts and jewelry.

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