阅读说明：本技术 一种氮化物红色复相荧光陶瓷及其制备方法 (Nitride red complex-phase fluorescent ceramic and preparation method thereof ) 是由 刘学建 彭星淋 姚秀敏 黄政仁 刘欢 葛盛 于 2020-04-27 设计创作，主要内容包括：本发明涉及一种氮化物红色复相荧光陶瓷及其制备方法,所述氮化物红色复相荧光陶瓷包括：氮化铝基质相,以及分散在氮化铝基质相中的氮化物红色荧光分散相；优选地,所述氮化物红色荧光分散相的含量为20～80wt%；优选地,所述氮化物红色荧光分散相选自CaAlSiN<Sub>3</Sub>:Eu<Sup>2+</Sup>、(Sr,Ca)AlSiN<Sub>3</Sub>:Eu<Sup>2+</Sup>和Sr<Sub>2</Sub>Si<Sub>5</Sub>N<Sub>8</Sub>:Eu<Sup>2+</Sup>中至少一种。(The invention relates to a nitride red complex phase fluorescent ceramic and a preparation method thereof, wherein the nitride red complex phase fluorescent ceramic comprises the following components: an aluminum nitride matrix phase and a nitride red fluorescent dispersed phase dispersed in the aluminum nitride matrix phase; preferably, theThe content of the nitride red fluorescent dispersion phase is 20-80 wt%; preferably, the red fluorescent disperse phase of nitride is selected from CaAlSiN 3 :Eu 2+ 、(Sr,Ca)AlSiN 3 :Eu 2+ And Sr 2 Si 5 N 8 :Eu 2+ At least one of them.)

1. A nitride red complex-phase fluorescent ceramic, which is characterized by comprising: an aluminum nitride matrix phase and a nitride red fluorescent dispersed phase dispersed in the aluminum nitride matrix phase; preferably, the content of the red nitride fluorescent disperse phase is 20-80 wt%; preferably, the red fluorescent disperse phase of nitride is selected from CaAlSiN₃:Eu^{2 +}、(Sr,Ca)AlSiN₃:Eu²⁺And Sr₂Si₅N₈:Eu²⁺At least one of them.

2. The nitride red complex phase fluorescent ceramic according to claim 1, wherein the nitride red complex phase fluorescent ceramic further comprisesContains not more than 5wt% of sintering aid; preferably, the sintering aid is selected from Y₂O₃MgO and CaF₂At least one of (1).

3. The nitride red complex phase fluorescent ceramic according to claim 1 or 2, wherein the thermal conductivity of the nitride red complex phase fluorescent ceramic is 42-232W/m-K.

4. A method for preparing the nitride red complex phase fluorescent ceramic according to any one of claims 1 to 3, comprising:

(1) mixing AlN powder, nitride red fluorescent powder and a sintering aid in a mortar to obtain mixed powder;

(2) pressing and molding the mixed powder to obtain a biscuit;

(3) and (3) sintering the mixed powder obtained in the step (1) or the biscuit obtained in the step (2) to obtain the nitride red complex phase fluorescent ceramic.

5. The preparation method according to claim 4, wherein the particle size of the aluminum nitride powder is in a range of 0.05 to 10 μm; the particle size range of the nitride red fluorescent powder is 5-30 microns; the particle size range of the sintering aid is 0.01-5 microns.

6. The preparation method according to claim 4 or 5, wherein the compression molding is dry compression molding or/and cold isostatic pressing, preferably dry compression molding and then cold isostatic pressing; more preferably, the pressure of the dry pressing is 10-15 MPa, the pressure maintaining time is 0.5-5 minutes, and the pressure of the cold isostatic pressing is 180-200 MPa, and the pressure maintaining time is 1-10 minutes.

7. The preparation method according to any one of claims 4 to 6, wherein the sintering temperature is 1700 to 1900 ℃, and the holding time is 5 minutes to 10 hours; preferably, the atmosphere of the sintering is a vacuum atmosphere or a nitrogen atmosphere.

8. The production method according to any one of claims 4 to 7, wherein when the mixed powder is sintered, the sintering is performed by spark plasma sintering or hot press sintering;

preferably, the pressure of the discharge plasma sintering is 30-80 MPa, the temperature is 1750-1850 ℃, and the time is 5-20 minutes; the pressure of the hot-pressing sintering is 30-80 MPa, the temperature is 1800-1900 ℃, and the time is 4-10 hours.

9. The production method according to any one of claims 4 to 7, wherein the obtained green body is sintered by at least one selected from the group consisting of air pressure sintering, vacuum sintering, atmospheric sintering and hot isostatic sintering;

preferably, the air pressure of the air pressure sintering is 5-10 MPa, the temperature is 1750-1850 ℃, and the time is 4-10 hours;

the temperature of the vacuum sintering is 1800-1900 ℃, and the time is 4-10 hours;

the temperature of the normal pressure sintering is 1800-1900 ℃, and the time is 4-10 hours;

the hot isostatic pressing sintering is carried out under the pressure of 100-200 MPa, at the temperature of 1600-1700 ℃ and for 4-10 hours.

10. The preparation method according to claim 8 or 9, characterized in that after the mixed powder is sintered by spark plasma, the mixed powder is subjected to decarbonization treatment by a gas pressure furnace or/and densification treatment by hot isostatic pressing;

carrying out hot-pressing sintering on the mixed powder, and then carrying out hot isostatic pressing densification treatment;

carrying out hot isostatic pressing densification treatment on the biscuit after air pressure sintering, vacuum sintering or normal pressure sintering;

the system of the decarbonization treatment of the pneumatic furnace comprises the following steps: a nitrogen atmosphere with the pressure of 5-10 MPa, the temperature of 1500-1850 ℃ and the time of 2-10 hours;

the hot isostatic pressing densification treatment system comprises: the atmosphere is nitrogen atmosphere, the pressure is 150-200 MPa, the temperature is 1600-1700 ℃, and the time is 2-10 hours.

Technical Field

The invention relates to a nitride red complex phase fluorescent ceramic material with high thermal conductivity and a preparation method thereof, belonging to the technical field of luminescent materials.

Background

LED lighting has become a new generation of lighting source due to energy conservation, green and environmental protection. However, the efficiency of LED is reduced at high power density, which is not satisfactory, and the laser chip LD provides an effective way to solve the problem. The laser illumination has the advantages of high electro-optic conversion efficiency, high brightness, long irradiation distance, small volume and the like, and is a next generation illumination light source which is accepted to replace an LED at present. The LED lamp is widely applied to many fields such as automobile headlights, laser televisions, outdoor lighting, ocean lighting and the like, and the influence and driving industries of the LED lamp reach trillion-level scale.

As a key material of a laser lighting technology, a fluorescent material mainly functions to convert incident partial laser into light of other colors to realize white light lighting, and the performance of the fluorescent material directly affects technical parameters such as color rendering index and stability of a lighting device. Since the LED is encapsulated with an organic resin having low thermal conductivity, there is a problem of yellowing when used for laser illumination. The fluorescent ceramic as a novel fluorescent material at present has excellent thermal, mechanical and optical properties and has the advantage of easily regulated microstructure, so that the fluorescent ceramic has excellent properties and wide market prospect.

The current research on fluorescent ceramics mainly has the problem of low color rendering index, mainly due to the lack of red component. The nitrogen (oxide) compound has stronger covalent bond property, the electron cloud expansion effect and the crystal field splitting effect are enhanced, the 5d energy level excitation energy is reduced, and the spectrum is red-shifted, so that the red fluorescent material with excellent performance is suitable for being prepared.

Therefore, a problem to be solved is to develop a red fluorescent ceramic with high thermal conductivity to improve the thermal stability and color rendering index of the device, so as to meet the light emission requirement of a high-power blue LD or LED light source.

Chinese patent No. 1 (application No. 201810257997.7) and Chinese patent No. 2 (application No. 201810259190.7) report that a garnet-based red fluorescent ceramic has good transmittance, but the thermal conductivity is very low, and the maximum value is only 9.6W/m.K. Although Chinese patent 3 (application No. 201810352648.3) reports a complex phase fluorescent ceramic using aluminum nitride as a matrix, the fluorescent powder is YAG Ce fluorescent powder or LuAG Ce fluorescent powder, and belongs to yellow or green fluorescent ceramic. At present, the preparation of the red complex phase fluorescent ceramic is not reported or disclosed in relevant documents.

Disclosure of Invention

Therefore, the invention aims to provide a nitride red complex-phase fluorescent ceramic material with ultrahigh thermal conductivity and a preparation method thereof.

In one aspect, the present invention provides a nitride red complex phase fluorescent ceramic, including: an aluminum nitride matrix phase and a nitride red fluorescent dispersed phase dispersed in the aluminum nitride matrix phase; preferably, the content of the nitride red fluorescent disperse phase is 20-80 wt%.

In the present disclosure, the nitride red complex-phase fluorescent ceramic is aluminum nitride as a matrix phase, and the nitride red fluorescent material dispersed in the aluminum nitride matrix phase is used as a fluorescent dispersion phase. Wherein: (1) the thermal conductivity of the aluminum nitride is very high, the theoretical thermal conductivity is as high as 320W/m.K, and is far higher than the thermal conductivity (about 4W/m.K) of the selected nitride red fluorescent disperse phase. Therefore, the nitride red complex phase fluorescent ceramic has excellent fluorescent property and high thermal conductivity. (2) Aluminum nitride is also a wide bandgap semiconductor, which is intrinsically absorbed in the ultraviolet region and does not affect the absorption of visible light by the red phosphor particles of nitride. (3) Chemical reaction does not theoretically occur between AlN and the red fluorescent disperse phase of nitride. (4) AlN may also be sintered into translucent ceramics and may also have some degree of transmittance.

Preferably, the red fluorescent disperse phase of nitride is selected from CaAlSiN₃:Eu²⁺、(Sr,Ca)AlSiN₃:Eu²⁺And Sr₂Si₅N₈:Eu²⁺At least one of them.

Preferably, the nitride red complex-phase fluorescent ceramic also contains no more than 5wt% of sintering aid; preferably, the sintering aid is selected from Y₂O₃MgO and CaF₂At least one of (1).

Preferably, the thermal conductivity of the nitride red complex phase fluorescent ceramic is 42-232W/m.K. To be used as CaAlSiN₃:Eu²⁺The thermal conductivity of the Solel nitride red complex phase fluorescent ceramic is explained in detail. Wherein the theoretical thermal conductivity of the matrix phase AlNAlN is as high as 320W/m.K and is far higher than that of CaAlSiN₃The ceramic (4W/m.K) was calculated by the Maxwell-Gault model as: when the AlN content is 80wt% and the fluorescent powder content is 20 wt%, the thermal conductivity of the obtained complex phase ceramic is as high as 232W/m.K; when the AlN content is 20 wt% and the phosphor content is 80wt%, the thermal conductivity of the obtained complex phase ceramic is still 48W/m.K. In consideration of the influence of sample compactness, the thermal conductivity range of the complex phase fluorescent ceramic is 20-80 wt% based on the content of the nitride red fluorescent disperse phase, and correspondingly changes between 42W/m.K and 232W/m.K, which is far higher than the thermal conductivity (about 20W/m.K) of most of fluorescent ceramics reported at present.

On the other hand, the invention also provides a preparation method of the nitride red complex phase fluorescent ceramic, which comprises the following steps:

(1) mixing AlN powder, nitride red fluorescent powder and a sintering aid in a mortar to obtain mixed powder;

(2) pressing and molding the mixed powder to obtain a biscuit;

(3) and (3) sintering the mixed powder obtained in the step (1) or the biscuit obtained in the step (2) to obtain the nitride red complex phase fluorescent ceramic.

Preferably, the particle size range of the aluminum nitride powder is 0.05-10 microns; the particle size range of the nitride red fluorescent powder is 5-30 microns; the particle size range of the sintering aid is 0.01-5 microns.

Preferably, the compression molding mode is dry compression molding or/and cold isostatic pressing, preferably dry compression molding is performed firstly and then cold isostatic pressing is performed; more preferably, the pressure of the dry pressing is 10-15 MPa, the pressure maintaining time is 0.5-5 minutes, and the pressure of the cold isostatic pressing is 180-200 MPa, and the pressure maintaining time is 1-10 minutes.

Preferably, the sintering temperature is 1700-1900 ℃, and the heat preservation time is 5 minutes-10 hours; preferably, the atmosphere of the sintering is a vacuum atmosphere or a nitrogen atmosphere.

Preferably, when the mixed powder is sintered, the sintering mode is spark plasma sintering or hot-press sintering.

Preferably, the pressure of the spark plasma sintering is 30-80 MPa, the temperature is 1750-1850 ℃, and the time is 5-20 minutes; the pressure of the hot-pressing sintering is 30-80 MPa, the temperature is 1800-1900 ℃, and the time is 4-10 hours.

Preferably, when the obtained green body is sintered, the sintering is performed by at least one selected from the group consisting of air pressure sintering, vacuum sintering, atmospheric sintering, and hot isostatic sintering.

Preferably, the pressure of the air pressure sintering is 5 to 10MPa, the temperature is 1750 to 1850 ℃, and the time is 4 to 10 hours;

the temperature of the vacuum sintering is 1800-1900 ℃, and the time is 4-10 hours;

the temperature of the normal pressure sintering is 1800-1900 ℃, and the time is 4-10 hours;

the hot isostatic pressing sintering is carried out under the pressure of 100-200 MPa, at the temperature of 1600-1700 ℃ and for 4-10 hours.

Preferably, the mixed powder is sintered by spark plasma, and then carbon removal treatment by a gas pressure furnace or/and hot isostatic pressing densification treatment are carried out. Further, preferably, the atmosphere furnace decarbonization treatment system includes: a nitrogen atmosphere with a pressure of 5 to 10MPa, at a temperature of 1500 to 1850 ℃ (e.g., 1600 ℃, 1700 ℃, 1800 ℃ and the like) for 2 to 10 hours; the hot isostatic pressing densification treatment system comprises: the atmosphere is nitrogen atmosphere, the pressure is 150-200 MPa, the temperature is 1600-1700 ℃, and the time is 2-10 hours.

Preferably, hot isostatic pressing densification treatment is performed after hot-pressing sintering is performed on the mixed powder. Preferably, the hot isostatic pressing densification process includes: the atmosphere is nitrogen atmosphere, the pressure is 150-200 MPa, the temperature is 1600-1700 ℃, and the time is 2-10 hours.

Preferably, the biscuit is subjected to air pressure sintering, vacuum sintering or normal pressure sintering, and then hot isostatic pressing densification treatment is carried out. Preferably, the hot isostatic pressing densification process includes: the atmosphere is nitrogen atmosphere, the pressure is 150-200 MPa, the temperature is 1600-1700 ℃, and the time is 2-10 hours.

Has the advantages that:

in the invention, the obtained complex phase fluorescent ceramic is a nitride red fluorescent ceramic with high thermal conductivity, high density and good mechanical strength, and the thermal conductivity is up to 232W/m.K through theoretical calculation and is far higher than that of most fluorescent ceramics on the market (about 20W/m.K);

according to the invention, the prepared nitride red fluorescent ceramic and yellow/green fluorescent ceramic can generate white light, so that the color temperature can be effectively reduced, and the color rendering index can be improved;

in the invention, the prepared nitride red fluorescent ceramic can be excited by a high-power blue LD or a blue LED, so that a high-power high-brightness illumination light source is realized, and the nitride red fluorescent ceramic has good application prospects in the fields of illumination and display.

Drawings

FIG. 1 is an XRD spectrum of the complex phase fluorescent ceramic (phosphor content 20% -50%) prepared in examples 1-4, from which it can be seen that samples with different phosphor contents only contain AlN and CaAlSiN₃Two phases, without other impurity phase, with increasing phosphor contentPlus, CaAlSiN₃The relative peak value of (a) is significantly increased;

FIG. 2 is an SEM image of the complex phase fluorescent ceramic prepared in example 3, wherein the gray large rod-shaped grains are CaAlSiN₃The fluorescent powder particles are prepared by adding sintering aid Y into black small equiaxed crystal grains of AlN crystal grains₂O₃The formed grain boundary phase is shown in the figure, and the fluorescent ceramic is sintered compactly and has no obvious air holes;

FIG. 3 is the excitation emission spectrum of the complex phase fluorescent ceramic prepared in example 4, from which it can be known that the prepared fluorescent ceramic can be excited by 450nm blue light and emits 650nm red light;

FIG. 4 is a thermal stability curve (from room temperature to 200 ℃) of the complex phase fluorescent ceramic prepared in example 3, from which it can be seen that the prepared fluorescent ceramic has better thermal stability, and when the temperature is increased from room temperature to 200 ℃, the luminous intensity is only reduced by 23%;

FIG. 5 is the excitation emission spectrum before and after the decarbonization with the atmospheric pressure furnace of the sample after the spark plasma sintering in example 13, from which it can be seen that the luminescent intensity of the fluorescent ceramic is greatly improved after the decarbonization with the atmospheric pressure furnace, which proves that the removal of carbon as a quenching center is favorable for the improvement of the luminescent property;

FIG. 6 is an optical photograph of the sample after discharge plasma sintering in examples 2 to 4 before and after decarburization in an air pressure furnace, and it is understood from the photograph that the sample before decarburization in the air pressure furnace is stained by carburization and turns black, and the sample after decarburization in the air pressure furnace becomes remarkably light in color (reddish).

Detailed Description

The present invention is further illustrated by the following examples, which are to be understood as merely illustrative and not restrictive.

In the present disclosure, the nitride red complex phase fluorescent ceramic includes: an aluminum nitride matrix phase and a nitride red phosphor dispersed phase. Wherein the component of the nitride red phosphor disperse phase is nitride red phosphor (hereinafter referred to as "phosphor"), preferably CaAlSiN₃:Eu²⁺、(Sr,Ca)AlSiN₃:Eu²⁺And Sr₂Si₅N₈:Eu²⁺And the like. More preferably, CaAlSiN₃:Eu²⁺、(Sr,Ca)AlSiN₃:Eu²⁺And Sr₂Si₅N₈:Eu²⁺Middle Eu²⁺The concentration of (b) can be 1-10 mol% respectively.

In an optional embodiment, the dispersed phase of the nitride red phosphor accounts for 20 to 80wt%, preferably 30 to 60 wt% of the total mass of the nitride red complex-phase fluorescent ceramic. The introduction of the aluminum nitride matrix realizes ultrahigh heat conductivity, and the improvement of the heat conductivity can enhance heat dissipation due to the fact that a large amount of heat can be generated in the use process of high-power solid-state lighting, so that the heat stability of the fluorescent material can be improved, the light-emitting saturation is reduced, and the improvement of the heat conductivity is very important. When the content of the nitride red fluorescent disperse phase is lower than 20 wt%, the obtained complex phase fluorescent ceramic has poor luminous performance due to the low content of the fluorescent powder. When the content of the red fluorescent dispersed phase is less than 20 wt%, the present inventors found that the color of the sample was gray black due to the excess AlN matrix phase to appear the color of AlN itself. When the content of the red phosphor is gradually increased, the sample gradually turns red, and it is generally considered that the more red the sample is, the higher the intensity of the red light emitted under the excitation of the blue light is. However, when the content of the red fluorescent disperse phase of nitride exceeds 80wt%, the obtained complex phase fluorescent ceramic has poor thermal stability due to the reduction of thermal conductivity caused by the low content of aluminum nitride.

The preparation process of the nitride red complex phase fluorescent ceramic is exemplarily described below.

Respectively weighing AlN powder, fluorescent powder and sintering aid with corresponding mass according to mass ratio, respectively adding into a mortar, and uniformly mixing to obtain mixed powder. Wherein, the purity of all the raw materials is not less than 99.5 percent. The mortar may be made of silicon nitride, or other materials such as agate, and the like, which is not limited herein. In addition, the mortar is selected for mixing the raw material substances in order to avoid the damage to the fluorescent powder particles in the ball milling process, because under the impact of the grinding balls, the agglomeration among the fluorescent particles can not be reduced, and a part of the fluorescent particles can be broken, the lost fluorescent particles can influence the luminescence property, and the problem can be avoided by mild manual grinding and mixing. Preferably, the ground mixed powder is sieved by a sieve of 100-200 meshes, so that uniform mixing is further ensured.

And carrying out dry pressing molding or/and cold isostatic pressing molding on the mixed powder to obtain a biscuit. The molding mode is preferably dry pressing and then cold isostatic pressing.

In an alternative embodiment, the mixed powder is directly sintered to prepare the nitride red complex-phase fluorescent ceramic. At the moment, the sintering mode of the mixed powder can comprise spark plasma sintering and hot-pressing sintering, and the ceramic material with higher density can be prepared without press forming. For example, when the spark plasma sintering mode is adopted, the graphite mold is directly mixed and loaded into the graphite mold without pre-forming, a layer of graphite paper is padded on the inner side of the graphite mold to prevent the graphite mold from directly contacting with mixed powder, a layer of carbon felt is wrapped on the outer side of the graphite mold to play a role in heat preservation and heat insulation, the loaded graphite mold is placed into a spark plasma sintering furnace, and finally spark plasma sintering is started.

In an alternative embodiment, the green body is sintered to prepare the nitride red complex phase fluorescent ceramic. In this case, the sintering method of the green compact includes air pressure sintering, vacuum sintering, atmospheric sintering, hot isostatic pressing sintering, and the like, and the present invention is not limited thereto, and one or a combination of a plurality of sintering methods may be selected as necessary.

In the invention, although the sintering modes of the mixed powder and the biscuit are different, the sintering system can be properly adjusted under the conditions that the sintering temperature is 1600-1900 ℃ and the heat preservation time is 5 min-10 h. The sintering atmosphere can be selected from vacuum or N₂An atmosphere. When the pressure sintering is selected, the pressure of the nitrogen can be 5-10 MPa. In addition, the pressure of the sintering modes such as hot-pressing sintering, hot isostatic pressing sintering, spark plasma sintering and the like is flexibly selected according to the sintering mode, and the range can be from no pressure to 200 MPa. For spark plasma sintering, the temperature rise rate is generally between 50 and 100 ℃, and the temperature drop rate can be 50 to 100 ℃/min after sintering. For other sintering modesThe temperature rise rate is generally between 5 and 10 ℃/min, and the temperature drop rate after sintering can be between 5 and 10 ℃/min.

In a further preferred implementation, because a graphite mold, graphite paper, a carbon felt and the like are selected when spark plasma sintering is adopted, the obtained nitride red complex phase fluorescent ceramic has the problem of carburization, and carbon permeated into the ceramic can become a quenching center to further influence the luminescence performance of the ceramic. This is because the presence of carbon affects the energy transfer between the luminescent centers and blackens the sample, reducing transparency. Moreover, since the nitride red complex phase fluorescent ceramic is a nitride system, a common oxidation treatment mode cannot be adopted. Therefore, the invention adopts a mode of air pressure sintering, and N is carried out at high temperature and high pressure₂Under the condition of (3), carbon element is replaced by nitrogen, so that the luminescence property is improved. At the same time, this method can also be used to relieve thermal stresses.

In a further preferred implementation, the compactness of the nitride red complex-phase fluorescent ceramic is generally less than 99% due to the adoption of discharge plasma sintering, air pressure sintering, vacuum sintering, normal pressure sintering, hot pressing sintering and the like. In order to further improve the compactness of the nitride red complex phase fluorescent ceramic, improve the heat conductivity and the transmissivity of the fluorescent ceramic and reduce the scattering of air holes to light, the invention adopts a hot isostatic pressing treatment mode to further promote the densification of the ceramic after the discharge plasma sintering. It should be noted that the composite material sintered by the spark plasma for the mixed powder may be subjected to the atmospheric pressure furnace decarbonization and the hot isostatic pressing densification treatment separately, or may be subjected to the atmospheric pressure furnace decarbonization and then the hot isostatic pressing densification treatment, or may be subjected to the hot isostatic pressing densification and then the atmospheric pressure furnace decarbonization treatment.

And (6) processing. And polishing the sintered nitride red complex-phase fluorescent ceramic by using a surface grinding machine and then carrying out double-sided polishing treatment. The shape and size of the obtained nitride red complex phase fluorescent ceramic are mainly selected according to a sintered mould and actual requirements. The obtained nitride red complex phase fluorescent ceramic is put into a processing chamber and the thickness is distributed between 0.1mm and 2 mm.

And (3) performance testing:

the compactness of the nitride red complex-phase fluorescent ceramic is at least more than 81 percent by adopting an Archimedes drainage method;

testing the quantum efficiency distribution of the nitride red complex phase fluorescent ceramic by using a fluorescence spectrometer, wherein the quantum efficiency distribution is between 30 and 44 percent;

and calculating the thermal conductivity distribution of the nitride red complex-phase fluorescent ceramic to be 42-232W/m.K by adopting a Maxwell-Gantt model.

Compared with the fluorescent ceramics reported at present, the nitride red complex phase fluorescent ceramics has the advantages that the thermal conductivity is greatly improved, the excellent thermal stability is obtained, the defects of the red fluorescent ceramics on the market are overcome, and the color rendering index can be improved by packaging the red fluorescent ceramics prepared by the method and the existing yellow fluorescent ceramics together. Moreover, the obtained nitride red complex-phase fluorescent ceramic can be used for high-power solid-state illumination, such as high-power blue LD or blue LED, and the stability and the color rendering index of illumination and display devices are improved.

The present invention will be described in detail by way of examples. It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art may be made in light of the above teachings. The specific process parameters and the like of the following examples are also only one example of suitable ranges, i.e., those skilled in the art can select the appropriate ranges through the description herein, and are not limited to the specific values exemplified below. In the following examples and comparative examples, the particle size of the red nitride phosphor was 5 to 30 μm, and the particle size of the aluminum nitride powder was 0.05 to 10 μm, unless otherwise specified.