WO2018045782A1

WO2018045782A1 - Preparation method for ceramic composite material, ceramic composite material, and light source apparatus

Info

Publication number: WO2018045782A1
Application number: PCT/CN2017/086863
Authority: WO
Inventors: 李乾; 陈雨叁; 许颜正
Original assignee: 深圳市绎立锐光科技开发有限公司
Priority date: 2016-09-09
Filing date: 2017-06-01
Publication date: 2018-03-15
Also published as: CN107805056A

Abstract

A preparation method for a ceramic composite material, comprising the following steps: material mixing: mixing a ceramic raw material with a fluorescent powder and prepressing at a preset pressure to produce a ceramic composite material green body, the ceramic raw material comprising either aluminum oxide or aluminum nitride, and the fluorescent powder being a garnet-structured fluorescent powder doped with a rare earth element; green body soaking: soaking the ceramic composite material green body in a soluble salt solution of a second sintering additive for 10-120 min, then drying the soaked ceramic composite material green body, and sintering at a temperature over the decomposition temperature of the soluble salt of the second sintering additive, thus allowing the second sintering additive to attach onto the interior of the ceramic composite material green body; and sintering: sintering in a protective atmosphere or vacuum the ceramic composite material green body having undergone the green body soaking step, thus producing the ceramic composite material.

Description

Method for preparing ceramic composite material, ceramic composite material and light source device

Technical field

The invention relates to the field of fluorescent ceramics, in particular to a method for preparing a ceramic composite material and a related ceramic composite material and a light source device.

Background technique

The technology of blue laser excitation of fluorescent materials to obtain visible light has been paid more and more attention with the development of laser display technology. The current research direction is mainly to develop new fluorescent materials (wavelength conversion materials) for the characteristics of laser-excited phosphors. The requirements are high luminous brightness, high-power laser irradiation, high optical conversion efficiency, and high thermal conductivity.

With the increasing demand for technology, the traditional silicone package phosphor technology and glass package phosphor technology can not meet the needs of high-end products. The temperature of silicone rubber can't exceed 200-250 °C. It is easy to age under long-term work in high temperature environment, and its life is not long. Moreover, the thermal conductivity of silica gel package and glass package is low, and it can't withstand high power or even super high power laser. Irradiation.

Due to its excellent thermal conductivity and high temperature resistance, ceramics have become the focus of next-generation laser-excited luminescent materials. In general, the formation conditions of ceramics are harsh, and hot pressing sintering or other high-pressure sintering methods are required to obtain ceramics of high performance parameters, but these methods have low production efficiency, high cost, and are difficult to mass-produce.

Summary of the invention

In view of the defects in the prior art that the fluorescent ceramics have low production efficiency and high production cost, the present invention provides a low-cost, high-efficiency method for preparing a fluorescent ceramic, comprising the following steps:

Mixing: mixing the ceramic raw material with the phosphor and pre-pressing at a preset pressure to obtain a ceramic composite green body, the ceramic raw material including one of alumina or aluminum nitride, and the phosphor is a rare earth doped pomegranate Phosphor of stone structure;

Green body impregnation: the ceramic composite green body is in the soluble salt solution of the second sintering aid Impregnating, then drying the impregnated ceramic composite green body, and calcining above the decomposition temperature of the soluble salt of the second sintering aid, so that the second sintering aid is adhered to the ceramic composite green body;

Sintering: The ceramic composite green body after the green body impregnation step is sintered under a protective atmosphere or under vacuum to obtain a ceramic composite material.

Preferably, the ceramic raw material has an average particle diameter of 0.05 to 1 μm, and the phosphor has an average particle diameter of 10 to 30 μm.

Preferably, the preset pressure is 5 to 200 MPa, and the concentration of the soluble salt solution of the second sintering aid is 1 to 5 mol/L.

Preferably, the second sintering aid is magnesium oxide, the soluble salt solution of the second sintering aid is a magnesium nitrate solution; or the second sintering aid is cerium oxide, and the soluble salt solution of the second sintering aid is a cerium nitrate solution; Or the second sintering aid is a mixing aid of magnesium oxide and cerium oxide, and the soluble salt solution of the second sintering aid is a mixed solution of magnesium nitrate and cerium nitrate.

Preferably, a plurality of blank impregnation steps are performed prior to the sintering step.

Preferably, the first green body impregnation and the second green body impregnation are included; the first green body impregnation comprises impregnating the ceramic composite green body in a soluble salt solution of the second sintering aid, and then impregnating the ceramic The composite green body is dried and calcined above the decomposition temperature of the soluble salt of the second sintering aid, so that the second sintering aid adheres to the ceramic composite green body; the second green body impregnation includes the ceramic composite material The green body is immersed in the soluble salt solution of the third sintering aid, and then the impregnated ceramic composite green body is dried and calcined above the decomposition temperature of the soluble salt of the third sintering aid, so that the third sintering aid The agent is attached to the ceramic composite green body; the order of the first green body immersion and the second green body immersion may be interchanged; the second sintering aid and the third sintering aid are different sintering auxiliaries.

Preferably, the second sintering aid is magnesium oxide, the third sintering aid is cerium oxide; or the second sintering aid is cerium oxide, the third sintering aid is magnesium oxide; or the second sintering aid is magnesium oxide and The cerium oxide mixing aid, the third sintering aid is cerium oxide or magnesium oxide; or the second sintering aid and the third sintering aid are mixing aids of magnesium oxide and cerium oxide in different proportions of components.

Preferably, in the mixing step, the step of mixing the ceramic raw material with the phosphor comprises mixing the ceramic raw material, the phosphor and the grinding solvent by ball milling.

Preferably, in the mixing step, the step of mixing the ceramic raw material with the phosphor comprises: mixing the ceramic raw material, the first sintering aid, and the phosphor.

Preferably, the first sintering aid comprises at least one of magnesium oxide, aluminum oxide, cerium oxide, calcium fluoride, and magnesium fluoride.

Preferably, the step of mixing the ceramic raw material, the first sintering aid and the phosphor comprises: mixing the ceramic raw material, the first sintering aid and the grinding solvent, then drying and calcining to obtain a mixed powder, and then mixing the mixed powder with The phosphor is mixed; or the step of mixing the ceramic raw material, the first sintering aid and the phosphor comprises: dispersing the ceramic raw material in the non-ionic surfactant aqueous solution, and disposing the soluble salt solution of the first sintering aid, The two solutions are mixed, and a precipitant aqueous solution is further added to obtain a suspension. The suspension is solid-liquid separated, and the solid component therein is calcined at a temperature higher than the decomposition temperature of the soluble salt of the first sintering aid to obtain a mixed powder, and then The mixed powder is mixed with the phosphor.

Preferably, the precipitating agent is soluble ammonium bicarbonate, hydrogen peroxide or an aqueous ammonia solution.

Preferably, the phosphor is an antimony doped yttrium aluminum garnet phosphor.

The invention also provides a ceramic composite material prepared by the above preparation method, the ceramic composite material comprises a ceramic body as a matrix and a phosphor as a luminescent center, the luminescent center is encapsulated in the matrix, and the ceramic body is an alumina ceramic Or aluminum nitride ceramics.

The invention also provides a light source device comprising an excitation light source and the above ceramic composite material, the ceramic composite material being located on the outgoing light path of the excitation light source.

Compared with the prior art, the present invention includes the following beneficial effects: the ceramic composite green body obtained after the mixing is immersed in the soluble salt solution of the sintering aid, so that the soluble salt of the sintering aid remains in the ceramic composite The internal voids of the green body of the material are calcined to increase the content of the sintering aid in the void, which promotes the liquid phase near the void during the sintering process, and can promote the particles around the void without hot pressing sintering. The transfer is beneficial to eliminate the pores and increase the relative density of the green body after sintering. The method of the present invention can be carried out in a general sintering furnace with respect to the method of hot press sintering, which greatly reduces the production cost.

DRAWINGS

Figure 1 is a schematic view showing the structure of an ideal ceramic composite green body;

2 is a schematic structural view of an actual ceramic composite green body;

3 is a schematic structural view of a ceramic composite green body after being impregnated with a blank;

Figure 4 is a flow chart of the preparation method of the present invention.

detailed description

The sintering densification process of ceramics is mainly promoted by the formation of a liquid phase inside the ceramic body during the sintering process. In the preparation of the luminescent ceramic, a liquid phase is formed in the hot press sintering mainly by adding a sintering aid, which lowers the sintering temperature and increases the density of the material. However, hot press sintering requires a special sintering furnace, which is costly and is not conducive to mass production.

In normal pressure or vacuum sintering, the raw material powder is pre-mixed, and then pre-pressed into a green body using a mold, and then placed in a furnace for sintering. The usual method is to mix the ceramic powder and the sintering aid as uniformly as possible, and then fill it into a mold for pre-pressing. However, due to the problem of powder fluidity and filling, the powder is piled up in the process of filling the mold and being pressed into the mold. The ideal green body should have a relative shape. Uniform, as shown in Figure 1, is a schematic diagram of the ideal ceramic composite green body. The ceramic raw material Al ₂ O ₃ particles are distributed around the phosphor particles, and the sintering aid MgO is evenly distributed between them. However, in the actual green body, the internal structure will have more structure as shown in Fig. 2, and Fig. 2 is a schematic structural view of the actual ceramic composite green body, which is caused when the powder is moved under pressure in the mold. The voids in Fig. 2 are formed between the particles due to inconsistent pressure, uneven friction between particles, and inconsistent particle flow. Due to the presence of these voids, the green body cannot fill the voids by sufficient mass transfer during normal pressure or vacuum sintering, and the voids eventually become closed pores or connected pores, affecting the properties of the material.

The preparation method provided by the invention comprises: immersing the pre-compressed ceramic composite green body in a soluble salt solution of the sintering aid, so that the large void inside the green body is filled with the soluble salt solution of the sintering aid, and then the green body is taken out Drying increases the amount of sintering aid around the void. After the impregnation-baking-calcination-precipitation sintering process, the internal structure of the green body is changed from the structure of Fig. 2 to the structure of Fig. 3, and Fig. 3 is the structure of the green composite body after the impregnation of the green body. The schematic diagram increases the amount of sintering aid in the void. During the sintering process, the liquid phase near the void is more pronounced, which can promote the material transfer around the void, which is beneficial to eliminate the pores and improve the relative density of the sintered ceramic composite.

The ceramic composite material of the present invention is a composite material having a light-emitting function, comprising a ceramic body as a matrix and a phosphor as a light-emitting center, wherein the light-emitting center is encapsulated in the matrix. The phosphor is a lanthanum aluminum garnet phosphor doped with rare earth elements, including various phosphors sold on the market; and the ceramic matrix is prepared from a ceramic raw material including one of alumina or aluminum nitride. It is characterized by low refractive index, good thermal conductivity and good light transmission.

In the preparation method of the present invention, the phosphor is first mixed into the ceramic raw material by mixing, and then the ceramic raw material is sintered to form a continuous ceramic, and the phosphor is encapsulated in the ceramic. During the preparation process, the phosphor does not participate in the reaction change, thereby maintaining the original luminescence properties. Since the melting point of the phosphor and the ceramic raw material are close, in the preparation process, when the ceramic raw material enters the liquid phase, the original structure of the phosphor is easily destroyed, and the obtained ceramic composite material has low luminous efficiency. By selecting a combination of a ceramic powder of a smaller particle size and a phosphor of a large particle size, the temperature at which the ceramic raw material enters the liquid phase can be lowered to some extent, and the stability of the phosphor during the preparation process is ensured. In order to further reduce the temperature at which the ceramic raw material powder enters the liquid phase, the preparation method of the present invention additionally adds a sintering aid which first enters the liquid phase during the heat treatment and causes the ceramic raw material to enter the liquid phase at a lower temperature. It promotes the sintering effect, not only improves the thermal conductivity and light transmission performance of the sintered body, but also ensures that as many phosphors as possible are not affected by excessive temperature during the heat treatment, and the physical structure and surface morphology are maintained. Therefore, the obtained fluorescent ceramic has good luminous efficiency. The high fluidity of the sintering aid at high temperatures also helps to purify grain boundary impurities, reduce the scattering of light as it passes through the grain boundaries, and contribute to the improvement of the light transmission properties of the ceramic.

The concept of the present invention is based on the problem of how to incorporate a sintering aid into a ceramic composite green body in which a ceramic raw material and a phosphor are mixed, and proposes a method step of the green body impregnation.

As shown in the flow chart of the preparation method of the present invention in FIG. 4, in the present invention, the method for preparing the ceramic composite material comprises the following steps:

Mixing: mixing the ceramic raw material with the phosphor and pre-pressing at a preset pressure to obtain a ceramic composite green body, the ceramic raw material comprising one of alumina or aluminum nitride, the phosphor being a rare earth element a doped garnet-structured phosphor;

Green body impregnation: immersing the ceramic composite green body in a soluble salt solution of the second sintering aid for 10 to 120 minutes, then drying the impregnated ceramic composite green body, and in the second sintering aid Calcining above the decomposition temperature of the soluble salt, so that the second burning a bonding aid is attached to the ceramic composite green body;

The rare earth element-doped garnet-structured phosphor is a phosphor obtained by a rare earth element-substituted garnet structure crystal (A ₃ B ₂ (XO ₄ ) ₃ , wherein A, B, and X refer to a cation). For example, Ce:Y ₃ Al ₅ O ₁₂ , Ce:Lu ₃ Al ₅ O ₁₂ , Ce:Gd ₃ Al ₅ O ₁₂ , Ce:Tb ₃ Al ₅ O ₁₂ , Ce:Y ₃ Ga ₅ O ₁₂ ,Ce:Lu ₃ Ga ₅ O ₁₂ , Ce: Gd ₃ Ga ₅ O ₁₂ , Ce: Tb ₃ Ga ₅ O ₁₂ or Eu: Y ₃ Al ₅ O ₁₂ or the like. Preferably, the phosphor is an antimony doped yttrium aluminum garnet phosphor.

Wherein, the ceramic material has an average particle diameter of 0.05 to 1 μm, and the phosphor has an average particle diameter of 10 to 30 μm. The particle size is set such that during the sintering process, the ceramic raw material enters the liquid phase and is sintered to obtain a ceramic, and the phosphor does not participate in the reaction. , to maintain the original shape and luminous performance.

The preset pressure is 5 to 200 MPa, and the pre-compression can make the powder into a sheet-like ceramic composite green body, which is not easily broken in the subsequent steps. The concentration of the soluble salt solution of the second sintering aid is 1 to 5 mol/L. At the high concentration, the soluble salt of the second sintering aid impregnated into the green body of the ceramic composite material can be as much as possible, and the greening impregnation step is reduced. The number of times.

The preparation method of the ceramic composite material of the present invention will be described in detail below.

In the embodiment of the present invention, the mixing step can be roughly divided into two schemes, one is to mix only the ceramic raw material with the phosphor, and the other is to mix the ceramic raw material, the phosphor and the first sintering aid. .

In the first technical solution, the step of mixing the ceramic raw material with the phosphor comprises mixing the ceramic raw material, the phosphor and the grinding solvent into a ball mill.

First, weigh a certain amount of ceramic raw material powder, put it into a ball mill tank, add an appropriate amount of grinding solvent (such as ethanol), thickener and dispersant, and then perform ball milling to obtain a viscous suspended slurry, and then add phosphor. The ball milling is continued to finally obtain a ceramic raw material-phosphor slurry. In this embodiment, a two-step ball milling method is adopted, so that the ceramic raw material powder having a small particle size and being difficult to be uniformly dispersed can be sufficiently dispersed first, and then the phosphor ball milling is added, thereby avoiding the ball milling of the phosphor for a long time and reducing the ball milling process. Damage to the phosphor. Of course, it is also possible to directly mix the two balls to reduce the number of processes.

Next, the obtained ceramic raw material-phosphor slurry is dried to obtain a dry powder, and then the dry powder is calcined to decompose and volatilize the organic components in the dry powder. Since the ceramic material and the phosphor have a high melting point and good thermal stability, the temperature at which the organic matter is removed does not affect the structure; at this temperature, the ceramic raw material and the phosphor are not oxidized, and thus can be in an aerobic atmosphere (e.g., Calcination is carried out under air). After calcination, a high-purity ceramic raw material-phosphor powder is obtained, which is granulated to increase the fluidity of the powder during the heat treatment, is favorable for press forming before heat treatment, and promotes the prepared fluorescent ceramic to be dense and uniform.

Then, the ceramic raw material-phosphor powder is weighed into an appropriate amount, and placed in a mold (such as a graphite mold or a steel mold), and pre-compressed at 5 to 200 MPa to obtain a ceramic composite green body.

In the mixing step of the second technical solution, the step of mixing the ceramic raw material with the phosphor comprises mixing the ceramic raw material with the first sintering aid to obtain a mixed powder, and then mixing the mixed powder with the phosphor, that is, the ceramic The raw material, the first sintering aid and the phosphor are mixed.

As outlined above for the impregnation of the green body, the purpose of the green body impregnation is to fill the voids of the ceramic composite green body obtained after pressing with a sintering aid to promote the transfer of particles around the void during the sintering process, and to eliminate pores. The effect of increasing the relative density of the sintered ceramic composite. However, for the compacted portion of the green body, the sintering aid at the void position has a limited effect.

Therefore, in the second embodiment of the compounding, the first sintering aid is incorporated into the ceramic composite in the mixing step before the impregnation of the green body, compared to the addition of the sintering only in the blank impregnation step. The auxiliary agent can not only disperse the first sintering aid in the ceramic composite raw material in advance, but also reduce the number of subsequent blank impregnation.

In the second technical solution of the mixing, the step of mixing the ceramic raw material with the first sintering aid to obtain the mixed powder comprises: mixing the ceramic raw material, the first sintering aid and the grinding solvent, then drying and calcining to obtain a mixture. powder. Specifically, firstly, a certain amount of ceramic raw materials and a first sintering aid are weighed into a ball mill tank, and a grinding solvent (such as ethanol), a thickener and a dispersing agent are added, and the first ball milling is performed to obtain a viscous suspension slurry. Then, the calcination is dried, and the grinding solvent, the thickener and the dispersing agent are removed to obtain a pure ceramic raw material-first sintering aid mixed powder. Of course, the mixing method is not limited to ball milling. The first sintering aid optionally includes at least one of magnesium oxide, aluminum oxide, cerium oxide, calcium fluoride, and magnesium fluoride.

For the second technical solution of the compounding, there are other embodiments, such as dispersing the ceramic raw material in the non-ionic surfactant aqueous solution, and dissolving the soluble salt of the first sintering aid. The liquid is mixed with the two solutions, and then a precipitant aqueous solution is added to obtain a suspension. The suspension is solid-liquid separated, and the solid component therein is calcined at a temperature higher than the decomposition temperature of the soluble salt of the first sintering aid to obtain a mixture. powder.

Specifically, first, a PEG (polyethylene glycol) aqueous solution having a mass fraction of 1 to 3% is disposed, and the ceramic raw material powder is mixed with the PEG aqueous solution, and ultrasonicated for 1 to 3 hours to disperse the powder in the solution. Then, a soluble salt solution (such as a magnesium nitrate solution) of the first sintering aid (such as MgO) is disposed at a concentration of 0.01 to 1 mol/L, and the PEG aqueous solution of the ceramic raw material powder is mixed with the soluble salt solution of the first sintering aid and placed Stirring was continued on the magnetic stirrer to obtain a mixed solution. An aqueous solution of 0.01 to 0.1 mol/L is prepared by using ammonium hydrogencarbonate as a precipitating agent, and the continuously stirred mixture is slowly dropped until the pH of the mixture is controlled to about 8 to 10, preferably 9 to 9.5. After maintaining the pH, stirring is continued for 1-5 h, preferably 2-3 h, to obtain a coprecipitated composite powder suspension. The suspension is centrifuged and solid-liquid separated, and the obtained solid component is washed with water several times and dried, and the obtained powder is calcined at a temperature higher than the decomposition temperature of the soluble salt of the first sintering aid (ie, magnesium nitrate) to obtain a ceramic raw material- A mixed powder of a sintering aid.

The first sintering aid may be magnesium oxide, cerium oxide or aluminum oxide. The soluble salt corresponding to magnesium oxide includes any soluble salt which can be decomposed at a high temperature to obtain magnesium oxide, such as magnesium nitrate, magnesium sulfate or magnesium sulfite. Soluble salts include cerium nitrate, barium sulfate, barium sulfite and the like which can be decomposed at high temperature to obtain cerium oxide. The soluble salts of alumina include aluminum nitrate, aluminum sulfate and the like which can be decomposed at high temperature to obtain solubility of alumina. salt.

In addition to ammonium bicarbonate, the precipitating agent may be other reagents for adjusting the pH such as hydrogencarbonate, hydrogen peroxide or ammonia.

In the second technical solution of the mixture, after the mixed powder of the ceramic raw material-first sintering aid is obtained, it is mixed with the phosphor in a ball mill tank, and an appropriate amount of ethanol is added as a grinding solvent, and the ultra-low wear rate is used. The zirconia balls were ball milled and the ball milling time was 1-120 min. After the completion of the ball milling, impurities such as a polishing solvent are removed, and granulated by sieving to obtain a mixed powder of a ceramic raw material-first sintering aid-phosphor, which is pre-compressed at 5 to 200 MPa to obtain a ceramic composite green body.

The blank impregnation step comprises first disposing a soluble salt solution of a second sintering aid (such as magnesium oxide) (such as a magnesium nitrate solution), and then immersing the ceramic composite green body in the solution so that the solution level does not pass over the top of the green body. , immersed in the solution for 10 to 120 minutes, so that the solution can be charged Divided into the internal void of the green body. Then, the impregnated ceramic composite green body is taken out, dried, and calcined at a temperature above the decomposition temperature of the soluble salt (magnesium nitrate) of the second sintering aid (200-500 ° C), so that the second void in the inner cavity of the green body The soluble salt (magnesium nitrate) of the sintering aid is converted into an insoluble second sintering aid (magnesium oxide) and adheres to the ceramic composite green body.

The soluble salt solution of the second sintering aid preferably has a concentration of 1 to 5 mol/L. At the high concentration, the soluble salt of the second sintering aid impregnated into the green body of the ceramic composite material can be as much as possible, and the green body is improved. The efficiency of impregnation.

The second sintering aid may be a single sintering aid of magnesium oxide or cerium oxide, or may be a mixing aid of magnesium oxide and cerium oxide, and the corresponding nitrate, sulfate, and sulfite are soluble salts used for impregnation. The second sintering aid may be the same as or different from the first sintering aid in the mixing step.

In the present invention, the effect of filling the voids with the second sintering aid can be achieved by one-time impregnation of the blank, but in practice, the sintering aid cannot be completely enriched in the voids, so multiple blanks are required. The impregnation step is to achieve the desired effect. Multiple blank impregnations can be carried out either in a soluble salt solution of the same sintering aid or in a soluble salt solution of different types of sintering aids.

In certain embodiments of the invention, a first green body impregnation and a second green body impregnation are included. The first blank impregnation comprises immersing the ceramic composite green body in a soluble salt solution of the second sintering aid, and then drying the impregnated ceramic composite green body, and the soluble salt of the second sintering aid Calcination is carried out above the decomposition temperature, so that the second sintering aid is adhered to the ceramic composite green body; the second green body impregnation comprises immersing the ceramic composite green body in the soluble salt solution of the third sintering aid, and then impregnating The subsequent ceramic composite green body is dried and calcined above the decomposition temperature of the soluble salt of the third sintering aid, so that the third sintering aid adheres to the ceramic composite green body. The first blank impregnation and the second blank impregnation here are only differentiated by using two different sintering aids, a second sintering aid and a third sintering aid, so that the first in-situ impregnation The order of the second blank impregnation can be interchanged arbitrarily.

In an embodiment of the present invention, preferably, the second sintering aid is cerium oxide, and the third sintering aid is magnesium oxide; in a more complicated solution, the second auxiliary agent may be a mixture of cerium oxide and magnesium oxide. The auxiliary agent, the third sintering aid is one of cerium oxide or magnesium oxide; The auxiliaries are cerium oxide or magnesium oxide, the third sintering aid is a mixing aid of magnesium oxide and cerium oxide, and the second sintering aid and the third sintering aid are respectively different proportions of magnesium oxide and cerium oxide. Mixing aids.

In the sintering step, the ceramic composite green body after the impregnation of the green body is placed in a sintering furnace, and sintered under a vacuum or a protective atmosphere (such as nitrogen, nitrogen-hydrogen mixed gas), and the sintering temperature is 1450 to 1700 ° C, and the temperature is kept. The time is 1 to 10 h, and after cooling is completed, the ceramic composite material is obtained. In the present invention, since the voids in the green body are filled with the sintering aid by the method of impregnation of the green body, the sintering aid first enters the liquid phase during the sintering process, and causes the ceramic raw material to enter the liquid phase at a lower temperature. It promotes the sintering, not only improves the thermal conductivity and light transmission properties of the sintered body, but also ensures that as many phosphors as possible are not affected by excessive temperature during the sintering process, and the physical structure and surface morphology are maintained. Therefore, the obtained ceramic composite material has good luminous efficiency.

The embodiments of the present invention are described in detail below with reference to the accompanying drawings and embodiments.

Embodiment 1

Mixing:

The raw material is selected from high-purity ultrafine alumina nano powder, the powder particle size is 0.05-1 μm, preferably 0.06-0.2 μm, and the PEG (polyethylene glycol) aqueous solution with a mass fraction of 1 to 3% is disposed, and the appropriate amount of alumina nanometer is prepared. The powder was mixed with an aqueous solution of PEG, and the aqueous PEG solution of alumina was sonicated for 1 to 3 hours and then used.

According to the ratio of magnesium oxide to alumina (0.01~2):100, weigh a certain amount of Mg(NO ₃ ) ₂ ·6H ₂ O, and divide these Mg(NO ₃ ) ₂ ·6H ₂ O into three Two parts are respectively arranged as a nitrate solution having different concentrations of a and b, wherein the concentration of a solution is 0.01 to 1 mol/L, and the solution of b is 1 to 5 mol/L.

The aqueous PEG aqueous solution is mixed with the a solution to obtain a mixed solution, which is placed on a magnetic stirrer and continuously stirred. The temperature is set to 20-80 ° C, preferably 40-60 ° C, and the rotational speed is 100-300 r/min.

Ammonium bicarbonate is used as a precipitant to prepare an aqueous solution of about 0.01 to 0.1 mol/L, and the mixed suspension which is continuously stirred is slowly dropped until the pH of the mixed suspension is controlled to about 8-10, preferably 9- 9.5. Suitable pH value for dispersion and deflocment of alumina ultrafine powder particles Condensation is very important. After maintaining a suitable pH value, stirring is continued for 1-5 h, preferably 2-3 h, to obtain a coprecipitated composite powder suspension.

The suspension was centrifuged, and the obtained powder was washed with water 2-8 times, and then vacuum dried at 50-150 ° C for 1-10 hours.

The obtained dry powder was calcined at 200-500 ° C to remove impurities, kept for 1-5 h, and then air-cooled with the furnace to obtain an alumina-magnesia mixed powder.

Weigh a certain amount of alumina-magnesia mixed powder, a certain amount of phosphor Ce:YAG, put two powders into the PTFE ball mill jar, add appropriate amount of ethanol as grinding solvent, and use ultra-low wear rate The zirconia balls are subjected to ball milling, and the ball milling time is from 1 to 120 min, preferably from 30 to 50 min. The ball milling time is shorter because the YAG phosphor powder has larger particles and is easier to disperse. If the ball milling time is too long, the grain surface morphology of the YAG phosphor powder is easily damaged and the luminescence property is affected.

After the ball mill is finished, the dry powder is obtained by vacuum constant temperature drying, and then granulated by a mesh of 80 mesh, 150 mesh, and 200 mesh to obtain a raw material powder having high fluidity. An appropriate amount of raw material powder is weighed into a steel mold, pre-compressed under a pressure of 5 to 200 MPa, and a green body is obtained after demolding.

Blank body impregnation:

The green body is infiltrated into the b solution, and the liquid level of the solution is not passed over the top of the green sample. The soaking time is from 10 min to 120 min, and then the green body after soaking is taken out, and after drying at 80 ° C, calcination is carried out at 200-500 ° C to convert the soluble magnesium nitrate mainly attached to the inner void of the green body into water-insoluble. Magnesium oxide. The infiltration process is repeated multiple times, but each time must be calcined to convert the magnesium nitrate.

sintering:

The green sample subjected to the infiltration process is placed in a sintering furnace and sintered under a vacuum or a nitrogen/nitrogen hydrogen atmosphere at a sintering temperature of 1450 to 1700 ° C and a holding time of 1-10 h. After the sintering is completed, a luminescent ceramic composite material is obtained. YAG-Al ₂ O ₃ -MgO.

Embodiment 2

Mixing:

The raw material is high-purity ultrafine alumina nano powder, the powder particle size is 0.06-0.2μm, the PEG aqueous solution with the mass fraction of 1-3% is arranged, the appropriate amount of alumina nano powder is mixed with the PEG aqueous solution, and the solution is ultrasonicated for 1~3h. After the backup.

According to the ratio of MgO to Al ₂ O ₃ (0.01～2):100, a certain amount of Mg(NO ₃ ) ₂ ·6H ₂ O is weighed and configured as a magnesium nitrate salt with a concentration of 0.01-1 mol/L. Solution, labeled as a solution.

The Al ₂ O ₃ solution was mixed with the a solution to obtain a mixed suspension, which was placed on a magnetic stirrer and continuously stirred, and the temperature was set to 40-60 ° C, and the rotation speed was 170-250 r/min.

Ammonium bicarbonate is used as a precipitant to prepare an aqueous solution of about 0.01 to 0.1 mol/L, and the mixed suspension which is continuously stirred is slowly dropped until the pH of the mixed suspension is controlled to about 9 to 9.5, and the pH is maintained. Stirring was continued for 2 to 3 hours to obtain a coprecipitated composite powder suspension.

The suspension was centrifuged, and the obtained solid was washed with water for 2 to 8 times, and then vacuum-dried at 50 to 150 ° C for 1 to 10 hours to obtain a dry powder.

The obtained dry powder is calcined at 200 to 500 ° C to remove impurities, and kept for 1 to 5 hours, and then air-cooled to obtain an Al ₂ O ₃ -MgO mixed powder.

Weigh a certain amount of Al ₂ O ₃ -MgO mixed powder and a certain amount of phosphor, put the two powders into a Teflon ball mill jar, add an appropriate amount of ethanol as a grinding solvent, and oxidize with ultra-low wear rate. The zirconium balls were ball milled and the ball milling time was 30-50 min.

Blank body impregnation:

A certain amount of Y(NO ₃ ) ₃ ·6H ₂ O was weighed and placed in a cerium nitrate salt solution having a concentration of 1 to 5 mol/L, which was designated as a b solution.

The green body is infiltrated into the b solution, that is, the cerium nitrate salt solution, and the liquid level of the solution is not passed over the top of the green sample. The soaking time is 60min-90min, then the green body after soaking is taken out, and after drying at 80 °C, calcination is carried out at 200-500 ° C, so that the soluble cerium nitrate mainly attached to the inner void of the green body is converted into water-insoluble. Yttrium oxide. The wetting process can be repeated as many times as needed, but each time must be calcined to convert the magnesium nitrate.

sintering:

The green sample subjected to the impregnation process is placed in a sintering furnace and sintered in a vacuum or a nitrogen-hydrogen mixed gas atmosphere at a sintering temperature of 1450 to 1700 ° C for a holding time of 1 to 10 h. After the sintering is completed, a luminescent ceramic composite material is obtained. .

Embodiment 3

Mixing:

Aluminum nitride having a particle diameter of 0.5 to 1 μm was weighed, placed in a ball mill jar, and an appropriate amount of an ethanol grinding solvent was added thereto, followed by addition of a grinding body to carry out ball milling. When the slurry in the ball mill tank is in a viscous suspension state, Ce:YAG phosphor particles having a particle diameter of 15 to 25 μm are added, and ball milling is continued until the phosphor powder is evenly distributed, and the ball milling is finished.

Then, the slurry is taken out, dried under vacuum to obtain a dry powder, and the dry powder is calcined in a muffle furnace to remove the organic component in the dry powder to obtain a high-purity aluminum nitride-phosphor powder. The powder was then sieved and granulated to obtain a high fluidity aluminum nitride-phosphor powder. An appropriate amount of aluminum nitride-phosphor powder was weighed into a mold, and press-molded at a pressure of 50 MPa to obtain a ceramic composite green body.

Blank body impregnation:

Weigh a certain amount of Mg(NO ₃ ) ₂ ·6H ₂ O and Y(NO ₃ ) ₃ ·6H ₂ O, respectively, to a concentration of 1 to 5 mol / L of magnesium nitrate solution - a solution and concentration of 1 ~5mol/L cerium nitrate solution - b solution.

The green body is immersed in the solution a, the immersion time is 60 min to 90 min, and then the green body after the immersion is taken out, and after drying at 80 ° C, the calcination is carried out at 200 to 500 ° C to make the soluble magnesium nitrate mainly adhered to the inner void of the green body. Change to water-insoluble magnesium oxide.

Then, the green body is immersed in the b solution, the immersion time is 60 min to 90 min, and then the green body after the immersion is taken out, and after drying at 80 ° C, the calcination is carried out at 200 to 500 ° C to make the soluble nitric acid mainly attached to the inner void of the green body. The hydrazine is converted into a water-insoluble cerium oxide.

sintering:

The green sample subjected to the impregnation process is placed in a sintering furnace and sintered in a vacuum atmosphere at a sintering temperature of 1450 to 1700 ° C and a holding time of 1 to 10 h. After the sintering is completed, a luminescent ceramic composite material is obtained.

Embodiment 4

Mixing:

The raw material is high-purity ultrafine alumina nano powder, the particle size of the powder is 0.08-0.2μm, and the high-purity ultra-fine nano-cerium oxide powder is selected, the particle size is 0.05-0.1μm, and the high-purity ultrafine nanometer magnesium oxide powder is selected. For 0.05-0.1 μm, choose Ce:YAG phosphor powder, the particle size is 15-20 μm.

A certain amount of alumina powder (30 wt%), cerium oxide powder (0.5 wt%), magnesium oxide powder (0.5 wt%), and Ce:YAG phosphor powder (69 wt%) were weighed. Alumina powder, cerium oxide powder and magnesium oxide powder are charged into a polytetrafluoroethylene ball mill tank, an appropriate amount of ethanol is added as a grinding solvent, and an appropriate amount of ceramic dispersant is added as a dispersing agent, and an ultra-low wear rate zirconia ball is used. The first ball milling was carried out and the ball milling time was 24 h.

After the first ball milling, a Ce:YAG phosphor was added to the ball mill jar for a second ball milling with a ball milling time of 40 min.

After the end of the two ball millings, drying was carried out by vacuum constant temperature to obtain a dry powder.

The dry powder was calcined at 600 ° C in a muffle furnace to remove organic components in the powder for 2 hours. The calcined powder is sieved and granulated to obtain a highly fluid fluorescent ceramic precursor powder. An appropriate amount of the fluorescent ceramic precursor powder was weighed into a mold, and pre-compressed under a pressure of 15 MPa to obtain a ceramic composite green body.

Blank body impregnation:

A certain amount of Mg(NO ₃ ) ₂ ·6H ₂ O and Y(NO ₃ ) ₃ ·6H ₂ O was weighed and placed in a mixed solution of magnesium nitrate lanthanum nitrate having a nitrate concentration of 1 to 5 mol/L.

The green body is immersed in the mixed solution for 60 minutes to 90 minutes, and then the green body after the immersion is taken out, dried at 80 ° C, and then calcined at 200 to 500 ° C to mainly adhere to the internal voids of the green body, magnesium nitrate and nitric acid. The hydrazine is converted into water-insoluble magnesium oxide and cerium oxide.

The blank impregnation step was repeated three times.

sintering:

The green sample subjected to the impregnation process is placed in a sintering furnace and sintered in a nitrogen-hydrogen mixed gas atmosphere at a sintering temperature of 1450 to 1700 ° C for a holding time of 1 to 10 h. After the sintering is completed, a luminescent ceramic composite material is obtained.

The invention also claims a ceramic composite material prepared by the above preparation method, the ceramic composite material comprising a ceramic body as a matrix and a phosphor as a luminescent center, the luminescent center being encapsulated in the matrix, the ceramic body being Alumina ceramic or aluminum nitride ceramic. Further, the phosphor is an antimony-doped yttrium aluminum garnet phosphor.

The invention further relates to a light-emitting device that is a wavelength-converting color wheel, the ceramic composite being disposed on a wavelength-converting color wheel.

The invention further relates to a light source device comprising an excitation source and a ceramic composite as described above, wherein the ceramic composite is disposed on the exiting light path of the excitation source for absorbing the excitation light and emitting the received laser light. The light source device can be applied to an illumination source such as a car headlight or a stage light, or can be used as a light source of the projector for image display.

The various embodiments in the present specification are described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same similar parts between the various embodiments may be referred to each other.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the invention and the drawings are directly or indirectly applied to other related technologies. The fields are all included in the scope of patent protection of the present invention.

Claims

A method for preparing a ceramic composite material, comprising the steps of:

Mixing: mixing the ceramic raw material with the phosphor and pre-pressing at a preset pressure to obtain a ceramic composite green body, the ceramic raw material comprising one of alumina or aluminum nitride, the phosphor being a rare earth element a doped garnet-structured phosphor;

Green body impregnation: immersing the ceramic composite green body in a soluble salt solution of the second sintering aid for 10 to 120 minutes, then drying the impregnated ceramic composite green body, and in the second sintering aid Calcining above the decomposition temperature of the soluble salt, so that the second sintering aid is adhered to the ceramic composite green body;

Sintering: The ceramic composite green body after the green body impregnation step is sintered under a protective atmosphere or under vacuum.
The production method according to claim 1, wherein the ceramic raw material has an average particle diameter of 0.05 to 1 μm, and the phosphor has an average particle diameter of 10 to 30 μm.
The preparation method according to claim 1, wherein the predetermined pressure is 5 to 200 MPa, and the concentration of the soluble salt solution of the second sintering aid is 1 to 5 mol/L.
The preparation method according to claim 1, wherein the second sintering aid is magnesium oxide, and the soluble salt solution of the second sintering aid is a magnesium nitrate solution; or

The second sintering aid is cerium oxide, and the soluble salt solution of the second sintering aid is a cerium nitrate solution; or

The second sintering aid is a magnesium oxide and cerium oxide mixing aid, and the soluble salt solution of the second sintering aid is a mixed solution of magnesium nitrate and cerium nitrate.
The production method according to claim 1, wherein the green body impregnation step is performed a plurality of times before the sintering step.
The preparation method according to claim 5, comprising a first green body impregnation and a second green body impregnation;

The first green body impregnation comprises immersing the ceramic composite green body in a soluble salt solution of a second sintering aid, and then drying the impregnated ceramic composite green body, and in the second sintering Calcining the decomposition temperature of the soluble salt of the auxiliary agent to make the second sintering aid adhere to the ceramic composite green body;

The second green body impregnation comprises immersing the ceramic composite green body in a soluble salt solution of a third sintering aid, and then drying the impregnated ceramic composite green body, and in the third sintering Calcining the decomposition temperature of the soluble salt of the auxiliary agent to make the third sintering aid adhere to the ceramic composite green body;

The second sintering aid and the third sintering aid are different sintering aids.
The preparation method according to claim 6, wherein the second sintering aid is magnesium oxide, and the third sintering aid is cerium oxide; or

The second sintering aid is cerium oxide, and the third sintering aid is magnesium oxide; or

The second sintering aid is a magnesium oxide and cerium oxide mixing aid, and the third sintering aid is cerium oxide or magnesium oxide; or

The second sintering aid and the third sintering aid are respectively a mixing aid of magnesium oxide and cerium oxide in different composition ratios.
The preparation method according to any one of claims 1 to 7, wherein in the mixing step, the step of mixing the ceramic raw material with the phosphor comprises: the ceramic raw material, the phosphor Mix the ball mill with the grinding solvent.
The preparation method according to any one of claims 1 to 7, wherein in the mixing step, the step of mixing the ceramic raw material with the phosphor comprises: the ceramic raw material, the first sintering aid The agent is mixed with the phosphor.
The production method according to claim 9, wherein the first sintering aid comprises at least one of magnesium oxide, aluminum oxide, cerium oxide, calcium fluoride, and magnesium fluoride.
The preparation method according to claim 9, wherein the step of mixing the ceramic raw material, the first sintering aid and the phosphor comprises: the ceramic raw material, the first sintering aid Mixing the ball mill with the grinding solvent, then drying and calcining to obtain a mixed powder, and then mixing the mixed powder with the phosphor; or

The step of mixing the ceramic raw material, the first sintering aid and the phosphor comprises: dispersing the ceramic raw material in a non-ionic surfactant aqueous solution, and disposing the soluble salt solution of the first sintering aid The two solutions are mixed, and then a precipitant aqueous solution is added to obtain a suspension. The suspension is solid-liquid separated, and the solid component therein is calcined at a temperature higher than a decomposition temperature of the soluble salt of the first sintering aid to obtain a suspension. The powder is mixed, and then the mixed powder is mixed with the phosphor.
The preparation method according to claim 11, wherein the precipitating agent is soluble ammonium hydrogencarbonate, hydrogen peroxide or an aqueous ammonia solution.
The preparation method according to claim 1, wherein the phosphor is an antimony-doped yttrium aluminum garnet phosphor.
A ceramic composite material obtained by the production method according to any one of claims 1 to 13, wherein the ceramic composite material comprises a ceramic body as a matrix and a phosphor as a luminescent center, the luminescent center being encapsulated in In the matrix, the ceramic body is an alumina ceramic or an aluminum nitride ceramic.
A light source device comprising an excitation light source and the ceramic composite material according to claim 14, the ceramic composite material being located on an exiting light path of the excitation light source.