WO2017157157A1 - 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷 - Google Patents

一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷 Download PDF

Info

Publication number
WO2017157157A1
WO2017157157A1 PCT/CN2017/074957 CN2017074957W WO2017157157A1 WO 2017157157 A1 WO2017157157 A1 WO 2017157157A1 CN 2017074957 W CN2017074957 W CN 2017074957W WO 2017157157 A1 WO2017157157 A1 WO 2017157157A1
Authority
WO
WIPO (PCT)
Prior art keywords
phosphor
aluminum nitride
powder
sintering
raw material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2017/074957
Other languages
English (en)
French (fr)
Inventor
李乾
许颜正
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Appotronics Corp Ltd
Original Assignee
Appotronics Corp Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CN201610160983.4A external-priority patent/CN107200589B/zh
Priority claimed from CN201610156064.XA external-priority patent/CN107200587B/zh
Priority claimed from CN201610156483.3A external-priority patent/CN107200588B/zh
Application filed by Appotronics Corp Ltd filed Critical Appotronics Corp Ltd
Publication of WO2017157157A1 publication Critical patent/WO2017157157A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
    • C04B35/581—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on aluminium nitride

Definitions

  • the invention relates to the field of fluorescent ceramics, in particular to a method for preparing a fluorescent ceramic of an aluminum nitride matrix and a related fluorescent ceramic.
  • 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.
  • a common YAG fluorescent ceramic is mainly calcined by raw material powders Al 2 O 3 , Y 2 O 3 , and CeO 2 , pressed into a sheet by a press, and then sintered to obtain a fluorescent ceramic. Since the fluorescent ceramic generally covers the surface of the LED, it is required to pursue a certain light transmittance. Therefore, the YAG fluorescent ceramic is more biased toward the transmittance, and the degree of grain growth is lower, resulting in a lower luminance of the light.
  • the thermal conductivity of conventional YAG ceramics is relatively low, generally 10 ⁇ 14W/(m ⁇ K).
  • the power of the light source is getting larger and larger, and the light conversion material is required to have higher
  • the thermal conductivity can quickly transfer a large amount of heat generated during the light conversion process.
  • the prepared fluorescent ceramic has low thermal conductivity and low luminous efficiency.
  • the invention provides a method for preparing an aluminum nitride matrix fluorescent ceramic, which comprises the following steps:
  • the slurry is dried, and then calcined in an aerobic atmosphere to remove water and organic matter therein to obtain a heat-treated raw material powder containing aluminum nitride and a phosphor;
  • Heat treatment heat-treating the heat-treated raw material powder to obtain a fluorescent ceramic, wherein the heat-treated raw material powder is subjected to high pressure treatment of 5 MPa or more before heat treatment and/or heat treatment, so that the heat-treated raw material powder is kept dense, and the heat treatment temperature is 1500 to 1850 ° C.
  • the heat treatment is carried out under an oxygen-free atmosphere.
  • the phosphor comprises YAG:Ce3+ or LuAG:Ce3+.
  • the phosphor accounts for 15 to 90% by mass of the heat-treated raw material powder.
  • the raw material further includes a sintering aid, and the sintering aid has a particle diameter of 0.05 to 1 ⁇ m.
  • the sintering aid comprises Y 2 O 3 , CaO, CaC 2 , La 2 O 3 or Dy 2 O 3 .
  • the phosphor accounts for 30-80% by mass of the total amount of the aluminum nitride powder, the sintering aid and the phosphor
  • the aluminum nitride accounts for the aluminum nitride powder, the sintering aid and the fluorescent material.
  • the mass percentage of the total amount of the powder is 17 to 69.5%
  • the sintering aid accounts for 0.5 to 3% by mass of the total amount of the aluminum nitride powder, the sintering aid, and the phosphor.
  • the first phosphor has a particle diameter of 15 to 30 ⁇ m, and the phosphor further includes a second phosphor having a particle diameter of 2 to 5 ⁇ m, the first phosphor and the second phosphor. It is a phosphor of the same material, and the first phosphor is more than the second phosphor.
  • the first phosphor accounts for 45-67% by mass of the total amount of the aluminum nitride powder and the phosphor
  • the second phosphor accounts for the mass of the total amount of the aluminum nitride powder and the phosphor.
  • the percentage is 5 to 10%
  • the aluminum nitride accounts for 28 to 45% by mass of the total amount of the aluminum nitride powder and the phosphor.
  • the raw material further comprises a thickener and a ceramic dispersing agent
  • the mixing step comprises first mixing the raw materials other than the phosphor with the grinding volume into the ball mill tank for the first ball milling. And then adding the second phosphor to the ball mill tank for a second ball milling; adding the first phosphor to the ball mill tank for a third ball milling; wherein, the first time The ball milling time is greater than the second ball milling time than the third ball milling time.
  • the raw material further comprises a thickener and a ceramic dispersing agent
  • the mixing step further comprises ball milling after mixing the raw material with a solvent.
  • the mixing step comprises first mixing a raw material other than the phosphor with the solvent into a ball mill tank, performing a first ball milling, and then adding the phosphor to a ball mill tank to perform the first A secondary ball mill in which the first ball milling time is greater than the second ball milling time.
  • the step of granulating the powder is carried out to obtain a powder having a particle size of 50 to 200 ⁇ m.
  • the heat treatment step comprises: forming the heat-treated raw material powder in a mold at a high pressure of 5 to 40 MPa, and then forming a high pressure molding at 150 to 300 MPa by cold isostatic pressing, removing the mold, and then conforming the high pressure molding.
  • the powder was placed in a microwave sintering furnace and heat-treated at 1600 to 1850 °C.
  • the heat treatment step comprises pre-forming the conforming powder in a mold at a high pressure of 5 to 40 MPa, and then placing the matching powder together with the mold in a hot press sintering furnace or a discharge plasma sintering furnace at 1500 to 1750.
  • the heat treatment is performed at °C.
  • a reduction treatment step of the fluorescent ceramic is further included, the reduction treatment step is performed under a reducing atmosphere, and the temperature environment of the reduction treatment step is 1200 to 1650 °C.
  • the present invention also provides a fluorescent ceramic prepared by the preparation method according to any one of the above.
  • the present invention includes the following beneficial effects:
  • the present invention is obtained by mixing aluminum nitride having a particle diameter of 0.1 to 1 ⁇ m with a phosphor having a particle diameter of 10 to 30 ⁇ m, and obtaining a high-purity heat-treated raw material powder containing aluminum nitride and a phosphor through a depurping process. Then, the heat-treated raw material powder is heat-treated at 1,500 to 1,850 ° C to obtain a fluorescent ceramic.
  • the selection of the aluminum nitride particle size and the high-pressure treatment process enable the aluminum nitride to enter the liquid phase at a lower temperature, and at this temperature, the selection of the phosphor particle size enables the surface morphology to be maintained.
  • the heat-treated raw material powder can maintain a dense, low porosity before and after sintering. Rate The state greatly improves the thermal conductivity of the fluorescent ceramics, thereby preparing a fluorescent ceramic having high thermal conductivity and high luminous efficiency.
  • the sintering aid and the aluminum nitride enter the liquid phase successively during the heat treatment, and the temperature of entering the liquid phase is lower, thereby avoiding The crystal morphology of the phosphor powder of the particle size of the invention is affected, so that the sintered fluorescent ceramic can ensure good luminous efficiency; at the same time, under the synergistic action of the particle size selection, high pressure treatment and heat treatment conditions of the aluminum nitride, nitrogen Aluminium-sintering aid-phosphor can maintain a dense, low porosity state before and after sintering, greatly improving the thermal conductivity of fluorescent ceramics, thereby preparing fluorescent ceramics with high thermal conductivity and high luminous efficiency.
  • the sintering aid can reduce the sintering temperature of the aluminum nitride powder, and the aluminum nitride powder can be more easily entered into the liquid phase sintering, which is beneficial to increase the density of the luminescent ceramic.
  • 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 present invention is obtained by mixing aluminum nitride having a particle diameter of 0.1 to 1 ⁇ m, a first phosphor having a particle diameter of 15 to 30 ⁇ m, and a second phosphor having a particle diameter of 2 to 5 ⁇ m, and purifying through a impurity removing process.
  • the powder is then subjected to heat treatment at 1,500 to 1,850 ° C to obtain a fluorescent ceramic.
  • aluminum nitride of a suitable particle size aluminum nitride enters the liquid phase successively during the heat treatment, and the temperature of entering the liquid phase is lower, avoiding the first step of the large particle size of the present invention.
  • the crystal morphology of the phosphor is affected, so that the sintered fluorescent ceramic can ensure good luminous efficiency; at the same time, under the synergistic action of the particle size selection, high pressure treatment and heat treatment conditions of aluminum nitride, the aluminum nitride-phosphor is Before and after sintering, it can maintain a dense, low porosity state, greatly improving the thermal conductivity of the fluorescent ceramics, thereby preparing fluorescent ceramics with high thermal conductivity and high luminous efficiency.
  • the first phosphor having a large particle diameter is more than the second phosphor having a small particle diameter, and the first phosphor has a high luminous efficiency, and the stability is better than that of the second phosphor during the heat treatment and sintering.
  • the high luminous efficiency of ceramics provides the basis.
  • the second phosphor has a small particle size, and when the aluminum nitride enters the liquid phase, the second phosphor partially or completely enters the liquid phase, and the portion enters the liquid.
  • the second phosphor of the phase has better bonding with the first phosphor than the aluminum nitride, so that the prepared fluorescent ceramic can have better bending strength; and the second fluorescent light without adding a small particle diameter
  • sintering heat treatment is required at a higher temperature, which may cause the surface structure of the first phosphor of large particle size to be damaged, resulting in a decrease in luminous efficiency.
  • FIG. 1 is a flow chart showing a method of preparing a fluorescent ceramic according to an embodiment of the present invention
  • FIG. 2 is a schematic structural view of a fluorescent ceramic according to an embodiment of the present invention.
  • FIG. 3 is a flow chart showing a method of preparing a fluorescent ceramic according to another embodiment of the present invention.
  • FIG. 4 is a flow chart showing a method of preparing a fluorescent ceramic according to another embodiment of the present invention.
  • the preparation of the fluorescent ceramics in the prior art is obtained by sintering the phosphor raw materials (ie, various types of oxides), and the fluorescent ceramics thus obtained have a luminous efficiency significantly lower than that of the phosphor powder obtained by the same raw materials.
  • the thermal conductivity of YAG ceramics is low, which is very disadvantageous for heat dissipation during use.
  • the fluorescent ceramic prepared by the aluminum nitride substrate of the invention directly adopts the existing commercial phosphor powder as a raw material, does not undergo the step of preparing the phosphor powder in the preparation process, and avoids each of the phosphor powder grain growth processes in the preparation of the fluorescent ceramics.
  • the problem is that the high thermal conductivity of aluminum nitride is used as the matrix, so that the obtained fluorescent ceramic finished product has good heat dissipation performance.
  • the melting point of the phosphor and the aluminum nitride are close to each other, even if the melting point of the phosphor is lower than the melting point of the aluminum nitride, in the preparation process, when the aluminum nitride enters the liquid phase, the original structure of the phosphor is easily destroyed, so that The obtained aluminum nitride-fluorescent fluorescent ceramic has low luminous efficiency.
  • the particle diameter of the aluminum nitride powder is much smaller than that of the phosphor, on the one hand, the temperature required for the aluminum nitride to enter the liquid phase is lowered, and on the other hand, it is ensured.
  • the phosphor can maintain a stable physical structure at this temperature, and at the same time, the phosphor has a high luminous efficiency of a large-sized phosphor.
  • the aluminum nitride has a small particle size, so that the high-pressure treatment in the preparation process can sufficiently fill the pores in the fluorescent ceramic, thereby increasing the density of the produced fluorescent ceramic.
  • Particle size selection, high pressure treatment process and heat treatment conditions of aluminum nitride and phosphor It is essential for the production of fluorescent ceramics with high thermal conductivity and high luminous efficiency. These conditions are influential and synergistic, and are indispensable.
  • the particle size referred to in the present invention means a median diameter D50.
  • FIG. 1 is a flow chart of a method for preparing a fluorescent ceramic according to an embodiment of the present invention. As shown, the preparation method sequentially includes the following steps:
  • the aluminum nitride-phosphor slurry is dried, and then calcined in an aerobic atmosphere to remove water and organic matter thereof to obtain a heat-treated raw material powder containing aluminum nitride and phosphor, which is aluminum nitride- Phosphor powder
  • heat treatment heat treatment of aluminum nitride-phosphor powder to obtain a fluorescent ceramic, wherein the aluminum nitride-phosphor powder is subjected to high pressure treatment before heat treatment and/or heat treatment, the heat treatment temperature is 1500 to 1850 ° C, and the heat treatment is not It is carried out under an oxygen atmosphere.
  • the first choice is the raw material.
  • the ultrafine aluminum nitride powder with a small particle size is selected, the particle size is 0.1 to 1 ⁇ m, and the particle size of the phosphor is much larger than that of aluminum nitride, which is 10 to 30 ⁇ m. .
  • the melting point of the phosphor YAG:Ce3+ is about 1970 ° C, and the melting point of aluminum nitride is 2200 ° C.
  • the physical structure of the phosphor has been destroyed, and even such a phosphor Forming, its luminous efficiency will also be significantly reduced.
  • the micro-nano-grade aluminum nitride powder can greatly reduce the temperature of entering the liquid phase, so that the aluminum nitride can enter the liquid phase before the phosphor, thereby avoiding the destruction of the physical structure of the phosphor.
  • the phosphor is YAG:Ce3+, and LuAG:Ce3+ or YAG/LuAG may be selected to be doped with other lanthanide phosphors.
  • the phosphor accounts for 15 to 90% by mass of the phosphor powder and the aluminum nitride total powder.
  • the phosphor must have a sufficient amount to ensure the luminous intensity of the fluorescent ceramic, and the higher the specific gravity of the phosphor, the more favorable the maximum luminescence intensity of the fluorescent ceramic; however, the aluminum nitride as the substrate must be sufficient. The amount can be guaranteed to be continuous, so the phosphor should not be too much.
  • it is mixed by ball milling.
  • grinding solvent such as ethanol
  • a phosphor was added to continue the ball milling to finally obtain an aluminum nitride-phosphor slurry.
  • a two-step ball milling method is adopted, so that the aluminum nitride 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. The process damages the phosphor.
  • the purpose of this step is to remove impurities such as a grinding solvent, a thickener, a dispersing agent, and the like in the aluminum nitride-phosphor slurry obtained in the mixing step, thereby obtaining high aluminum nitride and phosphor. Purity mixed powder.
  • the aluminum nitride-phosphor slurry is first 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 aluminum nitride and phosphor have high melting point and good thermal stability, the temperature at which organic matter is removed (generally below 1000 ° C) does not affect the structure of aluminum nitride and phosphor; at this temperature, aluminum nitride and The phosphor is also not oxidized, so it can be calcined under an aerobic atmosphere such as air.
  • the aluminum nitride-phosphor powder is granulated prior to the heat treatment step, and converted into an aluminum nitride-phosphor powder having a particle size of 50 to 200 ⁇ m.
  • the granulation result can increase the fluidity of the powder during the heat treatment, is favorable for high-pressure molding before and after the heat treatment, and promotes the prepared fluorescent ceramic to be dense and uniform.
  • the obtained high-purity aluminum nitride-phosphor powder is weighed into an appropriate amount, placed in a graphite mold, pre-formed at 5 to 40 MPa, and then placed together with the aluminum nitride-phosphor powder together with the mold.
  • high pressure sintering is carried out under a nitrogen atmosphere, and the sintering temperature is 1500 to 1750 °C.
  • the sintering temperature is 1500 to 1750 °C.
  • aluminum nitride enters the liquid phase, causing phase migration; while the phosphor does not enter or enter the liquid phase in a small amount, only a very small amount of phase migration occurs, so that the phosphor can maintain the original crystal shape. Appearance, its luminous intensity is not easily affected.
  • a nitrogen atmosphere is used to protect the aluminum nitride, and aluminum nitride is prevented from combining with oxygen in the phosphor to form aluminum oxide, thereby improving the purity of the finally obtained fluorescent ceramic aluminum nitride and ensuring high thermal conductivity.
  • the heat treatment sintering is performed under a vacuum atmosphere, which is more advantageous for gas exclusion inside the raw material, reducing the number of closed-cell pores and open pores, and is advantageous for obtaining high-density sintering.
  • the light transmission performance of the sintered body is also improved due to a large reduction in the refractive and scattering effects of the micropores.
  • the heat treatment sintering process can also be carried out in a nitrogen-hydrogen mixed gas or an inert gas such as argon to prevent the aluminum nitride or the phosphor from reacting with the heat treatment atmosphere.
  • the obtained high-purity aluminum nitride-phosphor powder is weighed into an appropriate amount, placed in a graphite mold, pre-formed at 5 to 40 MPa, and then nitrided.
  • the aluminum-phosphor powder was placed in a discharge plasma sintering furnace together with a mold, and sintered under high pressure in a nitrogen atmosphere at a sintering temperature of 1,500 to 1,750 °C.
  • a sintering temperature 1,500 to 1,750 °C.
  • the obtained high-purity aluminum nitride-phosphor powder is weighed in an appropriate amount, placed in a metal mold, pre-formed at 5 to 40 MPa, and then passed through High-pressure (150-300 MPa) cold isostatic pressing, the high-pressure molded aluminum nitride-phosphor powder is placed in a microwave sintering furnace, and sintered under a nitrogen atmosphere at a sintering temperature of 1600 to 1850 °C.
  • the preferred temperature increase rate of the heat treatment sintering process is 30 to 200 ° C / min (according to the heating capacity of each sintering equipment), and the aluminum nitride-phosphor powder is heated due to the impurity removing step and high pressure treatment before sintering.
  • the interior is kept dense and non-porous, and the product is not expanded due to the rapid heating rate, so that the product fluorescent ceramic is cracked.
  • the rapid heating rate allows the aluminum nitride-phosphor to avoid side reactions caused by prolonged heating (for example, reaction with the surrounding environment and reaction inside the phosphor), ensuring good transparency of the fluorescent ceramic. Thermal conductivity and luminescence properties.
  • the rapid temperature rise rate is less affected by the reaction of other chemicals.
  • the fluorescent ceramic obtained after the heat treatment further comprises a reduction treatment step of the fluorescent ceramic, the step being carried out under a reducing atmosphere (such as a nitrogen/hydrogen mixed gas), the reduction treatment being slightly lower than
  • the heat treatment sintering temperature is carried out at a reduction temperature of 1200 to 1650 °C.
  • the reduction process can remove the impurities adhering to the fluorescent ceramics in the heat treatment step, and prevent the impurities from becoming the heat generating center of the fluorescent ceramic in the working environment and affecting the use of the fluorescent ceramics.
  • the mass ratio of aluminum nitride to phosphor is the same for each example, and other conditions such as impurity removal and granulation are also the same.
  • the aluminum nitride having a particle diameter of 0.5 to 1 ⁇ m is weighed, placed in a ball mill jar, and an appropriate amount of a grinding solvent, a thickener, and a ceramic dispersant are added, and then the abrasive body is added to perform ball milling.
  • a grinding solvent e.g., a grinding solvent, a thickener, and a ceramic dispersant
  • the abrasive body is added to perform ball milling.
  • YAG:Ce3+ phosphor particles having a particle diameter of 15 to 25 ⁇ m are added, and ball milling is continued until the phosphor powder is evenly distributed, and the ball milling is finished.
  • 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 heat-treated raw material powder.
  • the aluminum nitride having a particle diameter of 0.1 to 0.5 ⁇ m is weighed and placed in a ball mill jar, and an appropriate amount of a grinding solvent, a thickener, and a ceramic dispersant are added, and then the abrasive body is added to perform ball milling.
  • a grinding solvent a thickener
  • a ceramic dispersant a grinding solvent, a thickener, and a ceramic dispersant
  • the abrasive body is added to perform ball milling.
  • LuAG:Ce3+ phosphor particles having a particle diameter of 12 to 15 ⁇ m are added, and ball milling is continued until the phosphor powder is evenly distributed, and the ball milling is finished.
  • 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 heat-treated raw material powder.
  • the sintering temperature is 1750 ⁇ 1850 ° C.
  • the sample obtained by sintering was subjected to a reduction treatment under a nitrogen/hydrogen mixed gas at a reduction temperature of 1,650 ° C to finally obtain a fluorescent ceramic.
  • the aluminum nitride having a particle diameter of 5 to 10 ⁇ m is weighed and placed in a ball mill jar, and an appropriate amount of a grinding solvent, a thickener, and a ceramic dispersant are added, and then a grinding body is added to perform ball milling. Pulp in the ball mill When the material is in a viscous suspension, YAG:Ce3+ phosphor particles having a particle size of 8 to 10 ⁇ m are added, and ball milling is continued until the phosphor distribution is uniform, and the ball milling is finished.
  • 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 heat-treated raw material powder.
  • the aluminum nitride-phosphor powder is directly sintered without high pressure treatment, and it is found that it is difficult to be sintered at 1750 ° C, and the temperature is raised to 2000 to 2100 ° C to obtain a fluorescent ceramic.
  • the porosity is high and can be microscopically Obviously see the stomata.
  • the aluminum nitride having a particle diameter of 1 to 5 ⁇ m is weighed and placed in a ball mill jar, and an appropriate amount of a grinding solvent, a thickener, and a ceramic dispersant are added, and then the grinding body is added to perform ball milling.
  • a grinding solvent e.g., a grinding solvent, a thickener, and a ceramic dispersant
  • the grinding body is added to perform ball milling.
  • LuAG:Ce3+ phosphor particles having a particle diameter of 8 to 15 ⁇ m are added, and ball milling is continued until the phosphor powder is evenly distributed, and the ball milling is finished.
  • 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 heat-treated raw material powder.
  • the aluminum nitride-phosphor powder was directly sintered without high-pressure treatment, and it was found to be difficult to be sintered at 1750 ° C. When the sintering temperature was raised to 1950 to 2050 ° C, the fluorescent ceramics could be sintered.
  • the fluorescent ceramics obtained in each of the examples and the comparative examples were tested to obtain thermal conductivity data and luminous efficiency data of the fluorescent ceramics.
  • the luminous efficiency of the fluorescent ceramic is irradiated with blue light of the same power and wavelength, and collected by an integrating sphere, and the ratio of the fluorescence emitted by the fluorescent ceramic to the blue light for irradiation per unit time is calculated.
  • the present invention uses a small particle size aluminum nitride as the fluorescent ceramic substrate.
  • the raw material and the high-pressure treatment of the aluminum nitride-phosphor powder in the heat treatment step can greatly reduce the heat treatment temperature, and obtain a fluorescent ceramic having a high density and a small change in the crystal morphology of the phosphor, and the thermal conductivity of the fluorescent ceramic. High, high luminous efficiency, suitable for high power laser illumination applications.
  • the fluorescent ceramic 100 includes a matrix aluminum nitride 110 and a phosphor 120 wrapped by a matrix 110, wherein the matrix aluminum nitride 110 is continuously distributed, and is dense.
  • the pores and the thermal conductivity are high, so that the heat generated by the phosphor 120 can be quickly derived.
  • the aluminum nitride 110 has high transparency and does not block the light emitted from the phosphor 120.
  • the temperature at which the aluminum nitride enters the liquid phase can be lowered to some extent.
  • the particle size of the phosphor itself may not be completely uniform, there is always a phosphor with a small partial particle size, which may damage the surface morphology and luminescence properties of the phosphor while the aluminum nitride enters the liquid phase, and reduce the fluorescent ceramic. Luminous efficiency.
  • the preparation method increases the sintering aid in addition to the aluminum nitride and the phosphor, and the sintering aid first enters the liquid phase during the heat treatment, and promotes the aluminum nitride in the It enters the liquid phase at a low temperature and acts to promote sintering, which not only improves the heat conduction 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 heat treatment, and are maintained.
  • the physical structure and surface morphology are stable, so that 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.
  • FIG. 3 is a flow chart of a method for preparing a fluorescent ceramic of the present embodiment. As shown, the preparation method sequentially includes the following steps:
  • the aluminum nitride-sintering aid-phosphor slurry is dried, and then calcined in an aerobic atmosphere to obtain a heat-treated raw material powder, which is an aluminum nitride-sintering aid-phosphor powder;
  • heat treatment heat treatment of aluminum nitride-sintering aid-phosphor powder to obtain a fluorescent ceramic, wherein the aluminum nitride-sintering aid-phosphor powder is subjected to high pressure treatment of 5 MPa or more before heat treatment and/or heat treatment, heat treatment
  • the temperature is 1500 to 1850 ° C, and the heat treatment is carried out under an oxygen-free atmosphere.
  • the first choice is the raw material.
  • the ultrafine aluminum nitride powder with a small particle size is selected, the particle size is 0.1 to 1 ⁇ m, and the sintering aid having a small particle size is selected, and the particle diameter is 0.05 to 1 ⁇ m.
  • the particle size of the phosphor is much larger than that of aluminum nitride and sintering aid, and is 10 to 30 ⁇ m.
  • the micro-nano-grade aluminum nitride powder and the sintering aid can further reduce the temperature of the liquid phase into the liquid phase, so that the aluminum nitride can enter the liquid phase before the phosphor, thereby avoiding the destruction of the physical structure of the phosphor.
  • the sintering aid is Y 2 O 3
  • other rare earth compounds or alkaline earth compounds such as CaO, CaC 2 , La 2 O 3 or Dy 2 O 3 may be selected.
  • the phosphor is YAG:Ce 3+
  • LuAG:Ce 3+ or YAG/LuAG may be selected to be doped with other lanthanide phosphors.
  • the phosphor accounts for 30 to 80% by mass of the total amount of the aluminum nitride, the sintering aid, and the phosphor powder.
  • the phosphor must have a sufficient amount to ensure the luminous intensity of the fluorescent ceramic, and the higher the specific gravity of the phosphor, the more favorable the maximum luminescence intensity of the fluorescent ceramic; however, the aluminum nitride as the substrate must be sufficient. The amount can be guaranteed to be continuous, so the phosphor should not be too much.
  • the sintering aid accounts for 0.5-3% by mass of the total amount of aluminum nitride, sintering aid and phosphor powder, and the effect is not obvious when the amount of sintering aid is too small; however, when the amount of sintering aid is too large, more than 3 wt% When it is, the growth of aluminum nitride is restricted, and the heterophase of alumina and aluminosilicate is produced, and the thermal conductivity and light transmittance of the fluorescent ceramic are lowered.
  • the mass percentage of aluminum nitride to the total amount of aluminum nitride, sintering aid and phosphor powder is 17 to 69.5%.
  • it is mixed by ball milling.
  • the slurry is further added with a phosphor, and a second ball milling is performed to finally obtain an aluminum nitride-sintering aid-phosphor slurry.
  • a two-step ball milling method is adopted, so that the aluminum nitride and the sintering aid powder having a small particle size and being difficult to disperse uniformly can be sufficiently dispersed first, and then the phosphor ball milling is added, and the time of the first ball milling is greater than the second time.
  • the time of ball milling avoids the ball milling of the phosphor for a long time and reduces the ball milling process. Damage to the phosphor.
  • the purpose of this step is to remove impurities such as a grinding solvent, a thickener, a dispersing agent, and the like in the aluminum nitride-sintering aid-phosphor slurry obtained in the mixing step to obtain a pure mixed powder. .
  • the aluminum nitride-sintering aid-phosphor slurry is first 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 aluminum nitride, sintering aids and phosphors have a high melting point and good thermal stability, the temperature at which organic matter is removed (generally below 1000 ° C) does not affect its structure; at this temperature, aluminum nitride, sintering The auxiliaries and phosphors are also not oxidized, so they can be calcined in an aerobic atmosphere such as air.
  • the powder before the heat treatment step, the powder is first granulated and converted into a powder having a particle size of 50 to 200 ⁇ m.
  • the granulation result can increase the fluidity of the powder during the heat treatment, is favorable for high-pressure molding before and after the heat treatment, and promotes the prepared fluorescent ceramic to be dense and uniform.
  • the obtained high-purity aluminum nitride-sintering aid-phosphor powder is weighed into an appropriate amount, placed in a graphite mold, pre-formed at 5 to 40 MPa, and then aluminum nitride-sintering aid -
  • the phosphor powder is placed in a hot press sintering furnace together with a mold, and sintered under high pressure in a nitrogen atmosphere at a sintering temperature of 1500 to 1750 °C.
  • the sintering aid At the sintering temperature, the sintering aid first enters the liquid phase, and promotes the entry of aluminum nitride into the liquid phase, resulting in phase migration; while the phosphor does not enter or enter the liquid phase in a small amount, only a very small amount of phase migration occurs.
  • the phosphor can maintain the original crystal morphology, and its luminous intensity is not easily affected.
  • a nitrogen atmosphere is used to protect the aluminum nitride, and aluminum nitride is prevented from combining with oxygen in the phosphor to form aluminum oxide, thereby improving the purity of the finally obtained fluorescent ceramic aluminum nitride and ensuring high thermal conductivity.
  • the heat treatment sintering is performed under a vacuum atmosphere, which is more advantageous for gas exclusion inside the raw material, reducing the number of closed-cell pores and open pores, and is advantageous for obtaining high-density sintering.
  • the light transmission performance of the sintered body is also improved due to a large reduction in the refractive and scattering effects of the micropores.
  • the heat treatment sintering process can also be carried out in a nitrogen-hydrogen mixed gas or an inert gas such as argon to prevent the aluminum nitride or the phosphor from reacting with the heat treatment atmosphere.
  • the high purity nitrogen obtained will be obtained during the heat treatment step.
  • Aluminium-sintering aid-phosphor powder is weighed in an appropriate amount, placed in a graphite mold, pre-compressed at 5 to 40 MPa, and then placed into aluminum nitride-sintering aid-phosphor powder together with a mold.
  • high pressure sintering is carried out under a nitrogen atmosphere, and the sintering temperature is 1500 to 1750 °C.
  • the sintering temperature is 1500 to 1750 °C.
  • localized high temperature is generated by discharge and ionization between grains, causing evaporation and melting on the surface of the powder particles, which promotes the densification process of the fluorescent ceramics and effectively reduces the sintering temperature.
  • the obtained high-purity aluminum nitride-sintering auxiliary-phosphor powder is weighed in an appropriate amount, placed in a metal mold, and pre-formed at 5 to 40 MPa. Then, after a higher pressure (150-300 MPa) cold isostatic pressing, the high-pressure formed aluminum nitride-sintering aid-phosphor powder is placed in a microwave sintering furnace and sintered under a nitrogen atmosphere at a sintering temperature of 1600. ⁇ 1850 ° C.
  • the fluorescent ceramic obtained after the heat treatment further includes a reduction treatment step of the fluorescent ceramic, which is carried out under a reducing atmosphere (for example, a nitrogen/hydrogen mixed gas), and the reduction treatment is performed at a temperature slightly lower than the heat treatment sintering temperature.
  • the reduction temperature is 1200 to 1650 °C.
  • the reduction process can remove the impurities adhering to the fluorescent ceramics in the heat treatment step, and prevent the impurities from becoming the heat generating center of the fluorescent ceramic in the working environment and affecting the use of the fluorescent ceramics.
  • 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, and then the powder is sieved and granulated to obtain a heat-treated raw material powder.
  • 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, and then the powder is sieved and granulated to obtain a heat-treated raw material powder.
  • the aluminum nitride having a particle diameter of 0.5 to 1 ⁇ m is weighed, added to a ball mill tank without adding a sintering aid, and an appropriate amount of a grinding solvent, a thickener and a ceramic dispersant are added, and then the grinding body is added to perform ball milling.
  • a grinding solvent e.g., a grinding solvent, a thickener and a ceramic dispersant
  • the grinding body is added to perform ball milling.
  • YAG:Ce 3+ phosphor particles having a particle diameter of 15 to 25 ⁇ m are added, and ball milling is continued until the phosphor powder is evenly distributed, and the ball milling is finished.
  • 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, and then the powder is sieved and granulated to obtain a heat-treated raw material powder.
  • the fluorescent ceramics obtained in each of the examples and the comparative examples were tested to obtain light transmittance, thermal conductivity data, and luminous efficiency data of the fluorescent ceramics.
  • the luminous efficiency of the fluorescent ceramics is passed Fluorescent ceramics were irradiated with blue light of the same power and wavelength, and integrated spheres were collected to calculate the ratio of the fluorescence emitted by the fluorescent ceramics per unit time to the blue light used for illumination.
  • the difference between the first embodiment and the first comparative example is that the particle diameter of the aluminum nitride participating in the sintering is different,
  • the aluminum nitride of the first embodiment is aluminum nitride having a small particle diameter
  • the aluminum nitride of the first comparative example is aluminum nitride having a large particle diameter. It can be seen from the tabular data and the experimental process that the use of small-diameter aluminum nitride as the raw material of the fluorescent ceramic matrix and the high-pressure treatment of the aluminum nitride-phosphor powder in the heat treatment step can greatly reduce the heat treatment temperature and obtain Fluorescent ceramic with high density and small change in crystal morphology of the phosphor.
  • the fluorescent ceramic has high light transmittance (avoiding light absorption and heat generation), high thermal conductivity (rapid heat dissipation), high luminous efficiency, and is suitable for high-power laser irradiation. Application environment.
  • the difference between the first embodiment and the second comparative example is that the first embodiment adds the sintering aid Y 2 O 3 , while the second embodiment does not add the sintering aid. It can be seen from the experimental process and the tabular data that the sintering temperature of the heat treatment process of the first embodiment is reduced to some extent by adding the sintering aid, and the light transmittance of the obtained fluorescent ceramic is also better. It can be inferred that the sintering aid enhances the fluidity of the powder during the sintering process, helps to purify grain boundary impurities, and improves the light transmission performance of the ceramic, thereby reducing the heat loss caused by light absorption.
  • the present invention also performs comparative tests on other sintering aids such as CaO, CaC 2 , La 2 O 3 or Dy 2 O 3 , etc., and the heat treatment temperature is lowered to some extent with respect to the technical solution without adding a sintering aid.
  • sintering aids such as CaO, CaC 2 , La 2 O 3 or Dy 2 O 3 , etc.
  • the invention also relates to an aluminum nitride matrix fluorescent ceramic prepared by the above preparation method, the fluorescent ceramic comprising a matrix aluminum nitride and a matrix-encapsulated phosphor, and a trace amount of a sintering aid, wherein the matrix aluminum nitride is continuously distributed. It is dense and has no pores and high thermal conductivity, so that the heat generated by the phosphor can be quickly exported. Moreover, aluminum nitride has high transparency and does not block the light emitted by the phosphor.
  • a single particle size phosphor can be replaced by a combination of a large particle size phosphor and a small particle size phosphor, so that during the sintering heat treatment, the small particle size phosphor enters the liquid phase, replacing the part.
  • Aluminum nitride is combined with a large particle size phosphor. Due to the same material, the combination of the small particle size phosphor and the large particle size phosphor is superior to the combination of the aluminum nitride and the large particle size phosphor, thereby promoting the overall preparation of the obtained fluorescent ceramic without increasing the sintering temperature.
  • the mechanical properties (bending resistance) are improved, making the fluorescent ceramics have better processability.
  • replacing part of the aluminum nitride with a small-sized phosphor also increases the luminous density of the fluorescent ceramic.
  • FIG. 4 is a flow chart of a method for preparing a fluorescent ceramic according to an embodiment of the present invention. As shown, the preparation method sequentially includes the following steps:
  • heat treatment heat treatment of aluminum nitride-phosphor powder to obtain a fluorescent ceramic, wherein the aluminum nitride-phosphor powder is subjected to high pressure treatment of 5 MPa or more before heat treatment and/or heat treatment, and the heat treatment temperature is 1500 to 1850 ° C, heat treatment It is carried out under an oxygen-free atmosphere.
  • the first choice is the raw material.
  • the ultrafine aluminum nitride powder with a small particle size is selected, the particle size is 0.1 to 1 ⁇ m, and the particle size of the first phosphor is much larger than that of aluminum nitride. ⁇ 30 ⁇ m, the particle size of the second phosphor is smaller than the particle diameter of the first phosphor, and is 2 to 5 ⁇ m, and the first phosphor and the second phosphor are the same phosphor.
  • the melting point of the phosphor YAG:Ce 3+ is about 1970 ° C
  • the melting point of aluminum nitride is 2200 ° C.
  • the micro-nano-grade aluminum nitride powder can greatly reduce the temperature of entering the liquid phase, so that the aluminum nitride can enter the liquid phase before the phosphor, thereby avoiding the destruction of the physical structure of the fluorescent powder.
  • the phosphor is YAG:Ce 3+
  • LuAG:Ce 3+ or YAG/LuAG may be selected to be doped with other lanthanide phosphors.
  • the first phosphor accounts for 45 to 67% by mass of the total amount of the aluminum nitride and the phosphor powder.
  • the first phosphor must have a sufficient amount to ensure the luminous intensity of the fluorescent ceramic, and the higher the specific gravity of the first phosphor, the more favorable the maximum luminescence intensity of the fluorescent ceramic; however, aluminum nitride as a matrix A sufficient amount is required to ensure continuous distribution, so the phosphor should not be excessive.
  • the aluminum nitride accounts for 28 to 45% by mass of the total amount of the aluminum nitride and the phosphor powder.
  • the second phosphor accounts for 5-10% by mass of the total amount of the aluminum nitride and the phosphor powder, and the second phosphor has a main function of filling the void around the first phosphor and combining with the first phosphor, and simultaneously bears A small part of the luminescence, the amount of the first phosphor is large, so it is necessary to have enough second phosphor to bind with it; however, since the second phosphor of small particle size has low luminous efficiency, it is not suitable for the specific gravity .
  • the material is mixed by ball milling.
  • First weigh a certain amount of aluminum nitride, put it into a ball mill jar, add an appropriate amount of grinding solvent (such as ethanol), thickener and dispersant, and then carry out the first ball milling to obtain a viscous suspended slurry, and then add
  • the second phosphor is subjected to a second ball milling, and the first phosphor is added to the ball mill tank for a third ball milling to finally obtain an aluminum nitride-phosphor slurry.
  • a three-step ball milling method is adopted, so that the aluminum nitride powder having a small particle size and being difficult to be uniformly dispersed can be sufficiently dispersed first, and then a small particle size second phosphor powder ball mill is added, and then a large particle size first is added.
  • Phosphor ball milling mainly considers that the smaller the particle size, the longer the particles are dispersed uniformly.
  • the time of the first ball milling is greater than the time of the second ball milling is greater than the time of the third ball milling, avoiding the ball milling of the phosphor for a long time, and reducing the damage of the phosphor during the ball milling process.
  • the purpose of this step is to remove impurities such as a grinding solvent, a thickener, a dispersing agent, and the like in the aluminum nitride-phosphor slurry obtained in the mixing step to obtain a pure mixed powder.
  • the aluminum nitride-phosphor slurry is first 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 aluminum nitride and phosphor have high melting point and good thermal stability, the temperature at which organic matter is removed (generally below 1000 °C) does not affect its structure; at this temperature, aluminum nitride and phosphors do not Oxidation, so calcination can be carried out under an aerobic atmosphere such as air.
  • the powder before the heat treatment step, the powder is first granulated and converted into a powder having a particle size of 50 to 200 ⁇ m.
  • the granulation result can increase the fluidity of the powder during the heat treatment, is favorable for high-pressure molding before and after the heat treatment, and promotes the prepared fluorescent ceramic to be dense and uniform.
  • the obtained high-purity aluminum nitride-phosphor powder is weighed into an appropriate amount, placed in a graphite mold, pre-formed at 5 to 40 MPa, and then placed together with the aluminum nitride-phosphor powder together with the mold.
  • high pressure sintering is carried out under a nitrogen atmosphere, and the sintering temperature is 1500 to 1750 °C.
  • the aluminum nitride first enters the liquid phase to cause phase migration, and then the second phosphor at least partially enters the liquid phase, and the first phosphor maintains the original crystal morphology, and the luminescence intensity is not easily affected.
  • a nitrogen atmosphere is used to protect the aluminum nitride, and aluminum nitride is prevented from combining with oxygen in the phosphor to form aluminum oxide, thereby improving the purity of the finally obtained fluorescent ceramic aluminum nitride and ensuring high thermal conductivity.
  • the heat treatment sintering is performed under a vacuum atmosphere, which is more advantageous for gas exclusion inside the raw material, reducing the number of closed-cell pores and open pores, and is advantageous for obtaining high-density sintering.
  • the light transmission performance of the sintered body is also improved due to a large reduction in the refractive and scattering effects of the micropores.
  • the heat treatment sintering process can also be carried out in a nitrogen-hydrogen mixed gas or an inert gas such as argon to prevent the aluminum nitride or the phosphor from reacting with the heat treatment atmosphere.
  • the obtained high-purity aluminum nitride-phosphor powder is weighed into an appropriate amount, placed in a graphite mold, pre-formed at 5 to 40 MPa, and then nitrided.
  • the aluminum-phosphor powder was placed in a spark plasma sintering furnace together with a mold, and sintered under high pressure in a nitrogen atmosphere at a sintering temperature of 1500 to 1750 °C.
  • a spark plasma sintering furnace together with a mold, and sintered under high pressure in a nitrogen atmosphere at a sintering temperature of 1500 to 1750 °C.
  • the obtained high-purity aluminum nitride-phosphor powder is weighed in an appropriate amount, placed in a metal mold, pre-formed at 5 to 40 MPa, and then passed through High-pressure (150-300 MPa) cold isostatic pressing, the high-pressure molded aluminum nitride-phosphor powder is placed in a microwave sintering furnace, and sintered under a nitrogen atmosphere at a sintering temperature of 1600 to 1850 °C. At the sintering temperature, aluminum nitride enters the liquid phase to cause phase migration; then the second phosphor partially enters the liquid phase, and the first phosphor maintains the original crystal morphology.
  • the fluorescent ceramic obtained after the heat treatment further comprises a reduction treatment step of the fluorescent ceramic, the step being carried out under a reducing atmosphere (such as a nitrogen/hydrogen mixed gas), the reduction treatment being slightly lower than
  • the heat treatment sintering temperature is carried out at a reduction temperature of 1200 to 1650 °C.
  • the reduction process can remove the impurities adhering to the fluorescent ceramics in the heat treatment step, and prevent the impurities from becoming the heat generating center of the fluorescent ceramic in the working environment and affecting the use of the fluorescent ceramics.
  • the step of uniformly adding the sintering aid to the solvent is further included, wherein the sintering aid accounts for 0.5 to 3 by mass of the total mass of the phosphor and the aluminum nitride. %, the sintering aid includes at least one of Y 2 O 3 , CaO, CaC 2 , La 2 O 3 or Dy 2 O 3 .
  • the amount of sintering aid is too small, the effect is not obvious; however, when the amount of sintering aid is too large, the growth of aluminum nitride is limited, and the heterophase of alumina and aluminosilicate is produced, and the thermal conductivity of the fluorescent ceramic is lowered. Light transmission.
  • the sintering aid can reduce the sintering temperature of the aluminum nitride powder, and the aluminum nitride powder can be more easily entered into the liquid phase sintering, which is beneficial to increase the density of the luminescent ceramic.
  • 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.
  • Aluminum nitride having a particle diameter of 0.5 to 1 ⁇ m was weighed into a ball mill jar, and an appropriate amount of a grinding solvent (ethanol), a thickener, and a ceramic dispersant were added, and then the grinding body was added thereto, followed by ball milling for 2 hours.
  • a grinding solvent ethanol
  • a thickener e.g., a ceramic dispersant
  • a ceramic dispersant e.g., aluminum nitride having a particle diameter of 0.5 to 1 ⁇ m
  • 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, and then the powder is sieved and granulated to obtain a heat-treated raw material powder.
  • the fluorescent ceramic was tested and found to have a light transmittance of 35%, a thermal conductivity of 60 W/(m ⁇ K), and a luminous efficiency of 62%. Among them, by using blue light to illuminate the fluorescent ceramic, and collecting the excited fluorescence by using an integrating sphere, the ratio of the fluorescence emitted by the fluorescent ceramic to the blue light for irradiation per unit time is calculated, and the luminous efficiency of the fluorescent ceramic is obtained.
  • the small particle size YAG:Ce 3+ phosphor particles in the first embodiment were replaced with the same size large-size YAG:Ce 3+ phosphor particles, and the fluorescent ceramics were prepared according to the same experimental conditions, and the fluorescent ceramics were found to be resistant to bending. The strength is lower than that of the fluorescent ceramic prepared in the first embodiment.
  • the invention also relates to an aluminum nitride matrix fluorescent ceramic prepared by the above preparation method, the fluorescent ceramic comprising a matrix aluminum nitride and a matrix-encapsulated phosphor, wherein the matrix aluminum nitride is continuously distributed, dense and non-porous, thermally conductive
  • the high rate allows the heat from the phosphor to be quickly exported.
  • aluminum nitride has high transparency and does not block the light emitted by the phosphor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Luminescent Compositions (AREA)

Abstract

一种氮化铝基质的荧光陶瓷的制备方法，依序包括以下步骤：混料：将原料与溶剂均匀混合得到浆料，原料至少包括氮化铝粉末和荧光粉，其中氮化铝粉末的粒径为0.1~1μm，荧光粉至少包括粒径为10~30μm的第一荧光粉；除杂：将浆料干燥，然后在有氧气氛下煅烧，除去其中的水和有机物，获得含有氮化铝和荧光粉的热处理原料粉末；热处理：热处理原料粉末在热处理前和/或热处理中经过5MPa以上高压处理，热处理在温度为1500~1850℃的无氧气氛下进行，即得到荧光陶瓷。

Description

一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷 技术领域
本发明涉及荧光陶瓷领域，特别是涉及一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷。
背景技术
蓝色激光激发荧光材料获得可见光的技术，随着激光显示技术的发展不断获得重视，当前的研究大方向主要是针对激光激发荧光粉的特性来开发新型的荧光材料(波长转换材料)，主要的要求是发光亮度高、能够承受大功率激光照射、光学转换效率高、导热性能高等特点。
传统的荧光陶瓷主要针对LED的发光特性开发，由于LED芯片的功率较小，发出的蓝光功率密度较低，因此针对LED开发的发光陶瓷的发光效率并没有得到足够的重视。比如常见的YAG荧光陶瓷主要由原料粉末Al2O3、Y2O3、CeO2煅烧后，压力机下压制成片，然后烧结得到荧光陶瓷。由于荧光陶瓷一般覆盖LED表面，需追求一定的透光性能，因此YAG荧光陶瓷比较偏向透光度性能，其中的晶粒成长程度较低，导致其发光亮度偏低。此外，传统的YAG陶瓷的热导率也相对较低，一般为10～14W/(m·K)，随着激光光源技术的发展，光源功率越来越大，要求光转换材料具有更高的热导性能，能够将光转化过程中产生的大量热量迅速的传递出去。
因此，一种获得高热导率、高发光效率的荧光陶瓷的制备方法亟待开发。
发明内容
针对上述现有技术中，制备得到的荧光陶瓷热导率低、发光效率低的缺陷，本发明提供一种氮化铝基质的荧光陶瓷的制备方法，依序包括以下步骤：
混料：将原料与溶剂均匀混合，所述原料至少包括氮化铝粉末和荧光粉，得到浆料，所述氮化铝粉末的粒径为0.1～1μm，所述荧光粉至少包括粒径为10～30μm的第一荧光粉；
除杂：将所述浆料干燥，然后将其在有氧气氛下煅烧，除去其中的水和有机物，获得含有氮化铝和荧光粉的热处理原料粉末；
热处理：将所述热处理原料粉末热处理，得到荧光陶瓷，其中，该热处理原料粉末在热处理前和/或热处理中经过5MPa以上高压处理，使所述热处理原料粉末保持致密，热处理温度为1500～1850℃，热处理在无氧气氛下进行。
优选地，所述荧光粉包括YAG：Ce3+或LuAG：Ce3+。
优选地，所述荧光粉占所述热处理原料粉末的质量百分比为15～90％。
优选地，所述混料步骤中，所述原料还包括烧结助剂，所述烧结助剂的粒径为0.05～1μm。
优选地，所述烧结助剂包括Y2O3、CaO、CaC2、La2O3或Dy2O3。
优选地，所述荧光粉占所述氮化铝粉末、烧结助剂和荧光粉总量的质量百分比为30～80％，所述氮化铝占所述氮化铝粉末、烧结助剂和荧光粉总量的质量百分比为17～69.5％，所述烧结助剂占所述氮化铝粉末、烧结助剂和荧光粉总量的质量百分比为0.5～3％。
优选地，所述混料步骤中，所述第一荧光粉粒径为15～30μm，所述荧光粉还包括第二荧光粉，粒径为2～5μm，第一荧光粉与第二荧光粉为材料相同的荧光粉，且第一荧光粉多于第二荧光粉。
优选地，所述第一荧光粉占所述氮化铝粉末和荧光粉总量的质量百分比为45～67％，所述第二荧光粉占所述氮化铝粉末和荧光粉总量的质量百分比为5～10％，所述氮化铝占所述氮化铝粉末和荧光粉总量的质量百分比为28～45％。
优选地，所述原料还包括增稠剂和陶瓷分散剂，所述混料步骤包括，首先将除所述荧光粉以外的其他原料与所述研磨容积装入球磨罐混合后进行第一次球磨；然后将所述第二荧光粉加入球磨罐，进行第二次球磨；再将所述第一荧光粉加入球磨罐，进行第三次球磨；其中，第一次 球磨时间大于第二次球磨时间大于第三次球磨时间。
优选地，所述混料步骤中，所述原料还包括增稠剂和陶瓷分散剂，所述混料步骤还包括将所述原料与溶剂混合后球磨。
优选地，所述混料步骤包括，首先将除所述荧光粉以外的其他原料与所述溶剂装入球磨罐混合后进行第一次球磨，然后再将所述荧光粉加入球磨罐，进行第二次球磨，其中，第一次球磨时间大于第二次球磨时间。
优选地，在所述热处理步骤前，包括将所述粉末造粒的步骤，得到颗粒大小为50～200μm的粉末。
优选地，所述热处理步骤包括，将所述热处理原料粉末在模具中5～40MPa一次高压成型，然后在150～300MPa冷等静压二次高压成型，取下模具，再将高压成型后的符合粉末放入微波烧结炉，在1600～1850℃进行热处理烧结。
优选地，所述热处理步骤包括，将所述符合粉末在模具中5～40MPa高压预成型，然后将所述符合粉末连同模具一同放入热压烧结炉或放电等离子烧结炉中，在1500～1750℃进行热处理烧结。
优选地，在烧结步骤后，还包括对荧光陶瓷的还原处理步骤，该还原处理步骤在还原气氛下进行，且还原处理步骤的温度环境为1200～1650℃。
本发明还提供了一种荧光陶瓷，该荧光陶瓷上述任一项所述的制备方法制备。
与现有技术相比，本发明包括如下有益效果：
(1)本发明通过将粒径为0.1～1μm的氮化铝与粒径为10～30μm的荧光粉混合，并经过除杂过程得到高纯度的含氮化铝和荧光粉的热处理原料粉末，然后将该热处理原料粉末在1500～1850℃下进行热处理，从而得到荧光陶瓷。本发明技术方案中，氮化铝粒径的选择及高压处理过程使得氮化铝得以在较低温度下进入液相，而且该温度下，荧光粉粒径的选择能够使其保持表面形貌基本不变，使得成型后的荧光陶瓷能够保留原荧光粉的发光性能；同时，在氮化铝的粒径选择和高压处理的协同作用下，热处理原料粉末在烧结前后能够保持一种致密、低孔隙率的 状态，极大的提高了荧光陶瓷的导热性能，从而制备出高热导率、高发光效率的荧光陶瓷。
(2)进一步地，本发明的原料中通过将粒径为0.1～1μm的氮化铝、粒径为0.05～1μm的烧结助剂与粒径为10～30μm的荧光粉混合，并经过除杂过程得到高纯度粉末，然后将粉末在1500～1850℃下进行热处理，从而得到荧光陶瓷。本发明技术方案中，通过选择合适粒径的氮化铝和烧结助剂，使得在热处理过程中，烧结助剂和氮化铝先后进入液相，而且其进入液相的温度较低，避免了对本发明粒径下的荧光粉的晶体形貌造成影响，使得烧结出的荧光陶瓷能够保证良好的发光效率；同时，在氮化铝的粒径选择、高压处理和热处理条件的协同作用下，氮化铝-烧结助剂-荧光粉在烧结前后能够保持一种致密、低孔隙率的状态，极大的提高了荧光陶瓷的导热性能，从而制备出高热导率、高发光效率的荧光陶瓷。烧结助剂能够降低氮化铝粉末的烧结温度，使氮化铝粉末更容易进入液相烧结，有利于提高发光陶瓷的致密度。烧结助剂在高温下的高流动性还有助于净化晶界杂质，减少光在经过晶界时发生的散射，有助于提高陶瓷的透光性能。
(3)本发明通过将粒径为0.1～1μm的氮化铝、粒径为15～30μm的第一荧光粉与粒径为2～5μm的第二荧光粉混合，并经过除杂过程得到纯净粉末，然后将粉末在1500～1850℃下进行热处理，从而得到荧光陶瓷。本发明技术方案中，通过选择合适粒径的氮化铝，使得在热处理过程中，氮化铝先后进入液相，而且其进入液相的温度较低，避免了对本发明大粒径的第一荧光粉的晶体形貌造成影响，使得烧结出的荧光陶瓷能够保证良好的发光效率；同时，在氮化铝的粒径选择、高压处理和热处理条件的协同作用下，氮化铝-荧光粉在烧结前后能够保持一种致密、低孔隙率的状态，极大的提高了荧光陶瓷的导热性能，从而制备出高热导率、高发光效率的荧光陶瓷。
本发明中，大粒径的第一荧光粉多于小粒径的第二荧光粉，第一荧光粉的发光效率较高，在热处理烧结过程中稳定性相对于第二荧光粉好，为荧光陶瓷的高发光效率提供了基础。而第二荧光粉粒径较小，在氮化铝进入液相时，第二荧光粉也部分或全部进入液相，该部分进入液 相的第二荧光粉相较于氮化铝具有与第一荧光粉更好的结合性，使得制备出的荧光陶瓷能够具有更好的抗弯强度；而在不添加小粒径的第二荧光粉的情况下，若要达到同等的抗弯强度，需要在更高的温度下进行烧结热处理，这将导致大粒径的第一荧光粉的表面结构可能受到破坏，导致发光效率的降低。
附图说明
图1为本发明一个实施例的荧光陶瓷的制备方法的流程图；
图2为本发明一个实施例的荧光陶瓷的结构示意图；
图3为本发明另一实施例的荧光陶瓷的制备方法的流程图；
图4为本发明另一实施例的荧光陶瓷的制备方法的流程图。
具体实施方式
正如背景技术所述，现有技术中的荧光陶瓷的制备通过将荧光粉原料(即各类氧化物)烧结制得，这样得到的荧光陶瓷，发光效率明显低于同样原料制备得到的荧光粉粉末，而且YAG陶瓷的热导率低，对于使用过程中的散热非常不利。本发明制备氮化铝基质的荧光陶瓷，直接采用已有的商用荧光粉作为原料，在制备过程中不经历荧光粉制备的步骤，避免了荧光陶瓷制备中荧光粉晶粒生长过程带来的各种问题，同时以高热导率的氮化铝作为基质，使得制得的荧光陶瓷成品具有良好的散热性能。
由于荧光粉和氮化铝的熔点接近，甚至荧光粉的熔点低于氮化铝的熔点，在制备过程中，当氮化铝进入液相时，荧光粉的原有结构容易遭到破坏，这样得到的氮化铝-荧光粉荧光陶瓷发光效率低。本发明中，通过选择合适粒径的氮化铝粉末和荧光粉，使得氮化铝粉末的粒径远小于荧光粉，一方面降低了氮化铝进入液相所需的温度，另一方面确保了荧光粉在该温度下能够保持物理结构稳定，同时使荧光粉具备大粒径荧光粉的高发光效率。此外，氮化铝粒径小，使得制备过程中的高压处理能够充分填充荧光陶瓷内的孔隙，提高了制得的荧光陶瓷的致密度。
氮化铝和荧光粉的粒径选择、高压处理过程、热处理条件共同构成 了制得热导率高、发光效率高的荧光陶瓷的必备条件，这些条件彼此相互影响、协同作用，不可或缺。
下面结合附图和实施方式对本发明实施例进行详细说明。
本发明所述的粒径，指中位粒径D50。
如图1为本发明实施例的荧光陶瓷的制备方法的流程图。如图所示，该制备方法依序包括以下步骤：
①混料：将原料包括氮化铝与荧光粉液相混合，得到氮化铝-荧光粉浆料，氮化铝的粒径为0.1～1μm，荧光粉的粒径为10～30μm；
②除杂：将氮化铝-荧光粉浆料干燥，然后将其在有氧气氛下煅烧，除去其中的水和有机物，获得含氮化铝和荧光粉的热处理原料粉末，为氮化铝-荧光粉粉末；
③热处理：将氮化铝-荧光粉粉末热处理，得到荧光陶瓷，其中，该氮化铝-荧光粉粉末在热处理前和/或热处理中经过高压处理，热处理温度为1500～1850℃，热处理在无氧气氛下进行。
在混料步骤中，首先是原料的选择，本实施例选用小粒径的超细氮化铝粉，粒径为0.1～1μm，荧光粉的粒径则远大于氮化铝，为10～30μm。一般而言，荧光粉YAG：Ce3+的熔点为1970℃左右，而氮化铝的熔点为2200℃，在氮化铝进入液相之前，荧光粉的物理结构已经被破坏，这样的荧光粉即使再成型，其发光效率也将明显下降。本实施例采用微纳米级的氮化铝粉，可以大幅降低其进入液相的温度，使得氮化铝能够先于荧光粉进入液相，避免了荧光粉物理结构的破坏。本实施例中，荧光粉为YAG：Ce3+，也可以选择LuAG：Ce3+或YAG/LuAG掺杂其他镧系元素的荧光粉。
本实施例中，荧光粉占荧光粉与氮化铝总粉料的质量百分比为15～90％。荧光粉作为发光中心，必须要有足够的量，才能保证荧光陶瓷发光强度，而且荧光粉的比重越高，越有利于荧光陶瓷最大发光强度的提高；但是，氮化铝作为基质，须达到足够的量才能保证连续分布，因此荧光粉不能过多。
本实施例中，采用球磨的方式混合。首先称取一定量的氮化铝粉末，装入球磨罐，添加适量的研磨溶剂(如乙醇)、增稠剂和分散剂，然后 进行球磨，得到粘稠悬浮状的浆料，再加入荧光粉，继续球磨，最终得到氮化铝-荧光粉浆料。本实施例采用二步球磨的方法，使得粒径较小、不易分散均匀的氮化铝粉能够先充分分散，然后再加入荧光粉球磨，避免了荧光粉过长时间的球磨，减少了该球磨过程对荧光粉的损害。
在除杂步骤中，该步骤的目的为将混料步骤中得到的氮化铝-荧光粉浆料中的研磨溶剂、增稠剂、分散剂等杂质除去，得到氮化铝和荧光粉的高纯度混合粉末。
本实施例中，首先对氮化铝-荧光粉浆料进行干燥，得到干粉，然后将干粉进行煅烧，使干粉中的有机成分分解、挥发。由于氮化铝和荧光粉的熔点高、热稳定性好，除去有机物的温度(一般在1000℃以下)不会对氮化铝和荧光粉的结构造成影响；在该温度下，氮化铝和荧光粉也不会氧化，因此可以在有氧气氛(如空气)下进行煅烧。
本实施例中，在热处理步骤之前，先对氮化铝-荧光粉粉末进行造粒，将其转为颗粒大小为50～200μm的氮化铝-荧光粉粉末。该造粒结果可以增加热处理过程中粉末的流动性，有利于热处理前后的高压成型，促使制备得到的荧光陶瓷致密而均匀。
在热处理步骤中，将得到的高纯度氮化铝-荧光粉粉末称取适量，装入石墨模具中，在5～40MPa下预压成型，然后将氮化铝-荧光粉粉末连同模具一同放入热压烧结炉中，在氮气气氛下高压烧结，烧结温度为1500～1750℃。该烧结温度下，氮化铝进入液相，产生物相迁移；而荧光粉不进入或很少量进入液相，只产生极小量的物相迁移，使得荧光粉能够保持原有的晶体形貌，其发光强度不易受到影响。本实施例采用氮气气氛，对氮化铝产生保护作用，避免氮化铝与荧光粉中的氧结合生成氧化铝，提高了最终得到的荧光陶瓷的氮化铝纯度，保证了高热导率。
在本发明的另一个实施例中，热处理烧结在真空气氛下进行，该气氛下，更有利于原料内部的气体排除，减少闭孔气孔和开孔气孔的数量，有利于获得高致密度的烧结体，由于大量减少的了微型气孔的折射与散射效应，烧结体的透光性能也获得提高。
此外，热处理烧结过程也可以在氮气氢气混合气或者惰性气体(如氩气)中进行，避免氮化铝或荧光粉与热处理气氛反应。
在本发明的另一个实施例中，在热处理步骤中，将得到的高纯度氮化铝-荧光粉粉末称取适量，装入石墨模具中，在5～40MPa下预压成型，然后将氮化铝-荧光粉粉末连同模具一同放入放电等离子烧结炉中，在氮气气氛下高压烧结，烧结温度为1500～1750℃。该烧结过程中，晶粒间的放电及电离化产生局部高温，在粉末颗粒表面引起蒸发和融化，促进了荧光陶瓷致密化的过程，有效的降低了烧结温度。
在本发明的另一个实施例中，在热处理步骤中，将得到的高纯度氮化铝-荧光粉粉末称取适量，装入金属模具中，在5～40MPa下预压成型，然后再经过更高压强(150～300MPa)的冷等静压成型，将高压成型后的氮化铝-荧光粉粉末放入微波烧结炉，在氮气气氛下烧结，烧结温度为1600～1850℃。该烧结温度下，氮化铝进入液相，产生物相迁移；而荧光粉不进入或很少量进入液相，只产生极小量的物相迁移，使得荧光粉能够保持原有的晶体形貌，其发光强度不易受到影响。本实施例的冷等静压成型后微波烧结的方式，相较于热压烧结和放电等离子烧结，需要更高的温度，这是由于本方案在烧结过程中没有保持对氮化铝-荧光粉的持续加压，同等温度下反应剧烈程度相对较低。
在本发明中，热处理烧结过程的优选升温速率为30～200℃/min(根据各烧结设备的升温能力)，由于烧结之前的除杂步骤及高压处理，使得氮化铝-荧光粉粉末在升温过程中保持内部致密无孔隙，不会因为升温速率快而体积明显膨胀以致产物荧光陶瓷开裂。同时，快速的升温速率使得氮化铝-荧光粉避免了长时间升温带来的副反应(例如与周围环境的反应、及荧光粉内部的反应)，确保了荧光陶瓷具有良好的透光性、导热性和发光性能。本发明中，由于热处理过程主要涉及物理变化，快速的升温速率对其的影响不如其他化学物反应中的大。
在本发明的实施例中，经过热处理后得到的荧光陶瓷，还进一步包括对荧光陶瓷的还原处理步骤，该步骤在还原气氛下进行(如氮气/氢气混合气体)，该还原处理在略低于热处理烧结温度下进行，还原温度为1200～1650℃。该还原处理过程可以将热处理步骤中附着在荧光陶瓷上的杂质去除，避免杂质成为荧光陶瓷在工作环境下的产热中心而影响荧光陶瓷的使用。
以下为不同条件下制备荧光陶瓷的各实施例对比，各例子的氮化铝与荧光粉的质量比相同，除杂、造粒等其他的条件也相同。
实施例一
称取粒径为0.5～1μm的氮化铝，装入球磨罐中，添加适量的研磨溶剂、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨。待球磨罐内的浆料成粘稠悬浮状时，加入粒径为15～25μm的YAG：Ce3+荧光粉颗粒，继续球磨至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，得到高纯度的氮化铝-荧光粉粉末。然后将该粉末过筛造粒，得到热处理原料粉末。
称取适量的原料粉末装入石墨模具，在5MPa压强下进行压制成型，将氮化铝-荧光粉粉末连同石墨模具放入热压烧结炉内，在氮气气氛下烧结，烧结温度为1650～1750℃。将烧结得到的样品，在氮气/氢气混合气体下高温脱碳还原处理，还原温度为1200℃，最终得到荧光陶瓷。
实施例二
称取粒径为0.1～0.5μm的氮化铝，装入球磨罐中，添加适量的研磨溶剂、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨。待球磨罐内的浆料成粘稠悬浮状时，加入粒径为12～15μm的LuAG：Ce3+荧光粉颗粒，继续球磨至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，得到高纯度的氮化铝-荧光粉粉末。然后将该粉末过筛造粒，得到热处理原料粉末。
称取适量的原料粉末装入金属模具，在40MPa压强下进行压制成型，然后再经过200MPa压强的冷等静压成型，将高压成型后的氮化铝-荧光粉放入微波烧结炉，在氮气气氛下烧结，烧结温度为1750～1850℃。将烧结得到的样品，在氮气/氢气混合气体下还原处理，还原温度为1650℃，最终得到荧光陶瓷。
对比例一
称取粒径为5～10μm的氮化铝，装入球磨罐中，添加适量的研磨溶剂、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨。待球磨罐内的浆 料成粘稠悬浮状时，加入粒径为8～10μm的YAG：Ce3+荧光粉颗粒，继续球磨至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，得到高纯度的氮化铝-荧光粉粉末。然后将该粉末过筛造粒，得到热处理原料粉末。
不经过高压处理，直接对氮化铝-荧光粉粉末进行烧结，发现在1750℃下难以烧结成型，将温度提高到2000～2100℃，烧结得到荧光陶瓷，然而其气孔率高，在显微镜下能明显看到气孔。
对比例二
称取粒径为1～5μm的氮化铝，装入球磨罐中，添加适量的研磨溶剂、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨。待球磨罐内的浆料成粘稠悬浮状时，加入粒径为8～15μm的LuAG：Ce3+荧光粉颗粒，继续球磨至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，得到高纯度的氮化铝-荧光粉粉末。然后将该粉末过筛造粒，得到热处理原料粉末。
不经过高压处理，直接对氮化铝-荧光粉粉末进行烧结，发现在1750℃下难以烧结成型，当烧结温度提高到1950～2050℃时，能够烧结得到荧光陶瓷。
将各个实施例、对比例得到的荧光陶瓷进行测试，获得荧光陶瓷的热导率数据及发光效率数据。其中，荧光陶瓷的发光效率通过采用相同功率和波长的蓝光照射荧光陶瓷，并采用积分球收集，计算单位时间内荧光陶瓷发出的荧光与用于照射的蓝光的比值。
各实施例、对比例的数据对比见下表：
  荧光陶瓷热导率/W/(m·K) 荧光陶瓷发光效率
实施例一 85 76％
实施例二 63 68％
对比例一 20 43％
对比例二 35 54％
由表格数据可以看出，本发明采用小粒径氮化铝作为荧光陶瓷基质 的原料，并在热处理步骤中对氮化铝-荧光粉粉末进行高压处理，可以大大降低热处理温度，并获得致密度高、荧光粉晶体形貌变化小的荧光陶瓷，该荧光陶瓷的热导率高、发光效率高，适用于大功率激光照射发光的应用环境。
如图2所示，为本发明实施例的荧光陶瓷的结构示意图，荧光陶瓷100包括基质氮化铝110和被基质110包裹的荧光粉120，其中基质氮化铝110呈连续分布状态，致密无气孔、热导率高，使得荧光粉120发出的热量能够被迅速导出。而且氮化铝110透明度高，不会对荧光粉120发出的光形成阻挡。
在上述发明实施例中，通过选择小粒径的氮化铝粉末，可以在一定程度上降低氮化铝进入液相的温度。但是，由于荧光粉本身粒径不可能完全均一，总有部分粒径偏小的荧光粉，在氮化铝进入液相的同时，可能损伤该部分荧光粉的表面形态和发光性能，降低荧光陶瓷的发光效率。
因此，在本发明的另一实施例中，制备方法在氮化铝和荧光粉之外，增加了烧结助剂，该烧结助剂在热处理过程中率先进入液相，并促使氮化铝在更低温度下进入液相，起到了促进烧结的作用，不但提高了烧结体的导热和透光性能，同时还确保了尽可能多的荧光粉在热处理过程中没有受到过高温度的影响，得以保持物理结构、表面形貌稳定，从而使得制得的荧光陶瓷具备良好的发光效率。烧结助剂在高温下的高流动性还有助于净化晶界杂质，减少光在经过晶界时发生的散射，有助于提高陶瓷的透光性能。
下面结合附图和实施方式对本实施例进行详细说明。
如图3为本实施例的荧光陶瓷的制备方法的流程图。如图所示，该制备方法依序包括以下步骤：
①混料：将含有氮化铝粉末、烧结助剂、荧光粉的原料与溶剂混合，得到氮化铝-烧结助剂-荧光粉浆料，氮化铝的粒径为0.1～1μm，荧光粉的粒径为10～30μm，烧结助剂的粒径为0.05～1μm；
②除杂：将氮化铝-烧结助剂-荧光粉浆料干燥，然后将其在有氧气氛下煅烧，获得热处理原料粉末，为氮化铝-烧结助剂-荧光粉粉末；
③热处理：将氮化铝-烧结助剂-荧光粉粉末热处理，得到荧光陶瓷，其中，该氮化铝-烧结助剂-荧光粉粉末在热处理前和/或热处理中经过5MPa以上高压处理，热处理温度为1500～1850℃，热处理在无氧气氛下进行。
在混料步骤中，首先是原料的选择，本实施例选用小粒径的超细氮化铝粉，粒径为0.1～1μm，并选用小粒径的烧结助剂，粒径为0.05～1μm，荧光粉的粒径则远大于氮化铝和烧结助剂，为10～30μm。本实施例采用微纳米级的氮化铝粉和烧结助剂，可以进一步大幅降低其进入液相的温度，使得氮化铝能够先于荧光粉进入液相，避免了荧光粉物理结构的破坏。
本实施例中，烧结助剂为Y2O3，也可以选择CaO、CaC2、La2O3或Dy2O3等其他稀土化合物或碱土化合物。
本实施例中，荧光粉为YAG：Ce3+，也可以选择LuAG：Ce3+或YAG/LuAG掺杂其他镧系元素的荧光粉。
本实施例中，荧光粉占氮化铝、烧结助剂和荧光粉粉末总量的质量百分比为30～80％。荧光粉作为发光中心，必须要有足够的量，才能保证荧光陶瓷发光强度，而且荧光粉的比重越高，越有利于荧光陶瓷最大发光强度的提高；但是，氮化铝作为基质，须达到足够的量才能保证连续分布，因此荧光粉不能过多。烧结助剂占氮化铝、烧结助剂和荧光粉粉末总量的质量百分比为0.5～3％，烧结助剂的量太少时作用不明显；但当烧结助剂的量过多，超过3wt％时，会限制氮化铝的生长，并产生氧化铝、铝钇酸盐的杂相，降低荧光陶瓷的热导率和透光性。氮化铝占氮化铝、烧结助剂和荧光粉粉末总量的质量百分比为17～69.5％。
本实施例中，采用球磨的方式混合。首先称取一定量的氮化铝和烧结助剂粉末，装入球磨罐，添加适量的研磨溶剂(如乙醇)、增稠剂和分散剂，然后进行第一次球磨，得到粘稠悬浮状的浆料，再加入荧光粉，进行第二次球磨，最终得到氮化铝-烧结助剂-荧光粉浆料。本实施例采用二步球磨的方法，使得粒径较小、不易分散均匀的氮化铝和烧结助剂粉末能够先充分分散，然后再加入荧光粉球磨，第一次球磨的时间大于第二次球磨的时间，避免了荧光粉过长时间的球磨，减少了该球磨过程 对荧光粉的损害。
在除杂步骤中，该步骤的目的为将混料步骤中得到的氮化铝-烧结助剂-荧光粉浆料中的研磨溶剂、增稠剂、分散剂等杂质除去，得到纯净的混合粉末。
本实施例中，首先对氮化铝-烧结助剂-荧光粉浆料进行干燥，得到干粉，然后将干粉进行煅烧，使干粉中的有机成分分解、挥发。由于氮化铝、烧结助剂和荧光粉的熔点高、热稳定性好，除去有机物的温度(一般在1000℃以下)不会对其的结构造成影响；在该温度下，氮化铝、烧结助剂和荧光粉也不会氧化，因此可以在有氧气氛(如空气)下进行煅烧。
本实施例中，在热处理步骤之前，先对粉末进行造粒，将其转为颗粒大小为50～200μm的粉末。该造粒结果可以增加热处理过程中粉末的流动性，有利于热处理前后的高压成型，促使制备得到的荧光陶瓷致密而均匀。
在热处理步骤中，将得到的高纯度氮化铝-烧结助剂--荧光粉粉末称取适量，装入石墨模具中，在5～40MPa下预压成型，然后将氮化铝-烧结助剂-荧光粉粉末连同模具一同放入热压烧结炉中，在氮气气氛下高压烧结，烧结温度为1500～1750℃。该烧结温度下，烧结助剂率先进入液相，并促使氮化铝进入液相，产生物相迁移；而荧光粉不进入或很少量进入液相，只产生极小量的物相迁移，使得荧光粉能够保持原有的晶体形貌，其发光强度不易受到影响。本实施例采用氮气气氛，对氮化铝产生保护作用，避免氮化铝与荧光粉中的氧结合生成氧化铝，提高了最终得到的荧光陶瓷的氮化铝纯度，保证了高热导率。
在本发明的另一个实施例中，热处理烧结在真空气氛下进行，该气氛下，更有利于原料内部的气体排除，减少闭孔气孔和开孔气孔的数量，有利于获得高致密度的烧结体，由于大量减少的了微型气孔的折射与散射效应，烧结体的透光性能也获得提高。
此外，热处理烧结过程也可以在氮气氢气混合气或者惰性气体(如氩气)中进行，避免氮化铝或荧光粉与热处理气氛反应。
在本发明的另一个实施例中，在热处理步骤中，将得到的高纯度氮 化铝-烧结助剂-荧光粉粉末称取适量，装入石墨模具中，在5～40MPa下预压成型，然后将氮化铝-烧结助剂-荧光粉粉末连同模具一同放入放电等离子烧结炉中，在氮气气氛下高压烧结，烧结温度为1500～1750℃。该烧结过程中，晶粒间的放电及电离化产生局部高温，在粉末颗粒表面引起蒸发和融化，促进了荧光陶瓷致密化的过程，有效的降低了烧结温度。
在本发明的另一个实施例中，在热处理步骤中，将得到的高纯度氮化铝-烧结助剂-荧光粉粉末称取适量，装入金属模具中，在5～40MPa下预压成型，然后再经过更高压强(150～300MPa)的冷等静压成型，将高压成型后的氮化铝-烧结助剂-荧光粉粉末放入微波烧结炉，在氮气气氛下烧结，烧结温度为1600～1850℃。该烧结温度下，氮化铝进入液相，产生物相迁移；而荧光粉不进入或很少量进入液相，只产生极小量的物相迁移，使得荧光粉能够保持原有的晶体形貌，其发光强度不易受到影响。本实施例的冷等静压成型后微波烧结的方式，相较于热压烧结和放电等离子烧结，需要更高的温度，这是由于本方案在烧结过程中没有保持对氮化铝-烧结助剂-荧光粉的持续加压，同等温度下反应剧烈程度相对较低。
同样地，经过热处理后得到的荧光陶瓷，还进一步包括对荧光陶瓷的还原处理步骤，该步骤在还原气氛下进行(如氮气/氢气混合气体)，该还原处理在略低于热处理烧结温度下进行，还原温度为1200～1650℃。该还原处理过程可以将热处理步骤中附着在荧光陶瓷上的杂质去除，避免杂质成为荧光陶瓷在工作环境下的产热中心而影响荧光陶瓷的使用。
以下为不同条件下制备荧光陶瓷的各实施例对比，除杂、造粒等其他的条件相同。
实施例一
称取粒径为0.5～1μm的氮化铝和0.05～0.1μm的Y2O3烧结助剂装入球磨罐中，添加适量的研磨溶剂(乙醇)、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨。待球磨罐内的浆料成粘稠悬浮状时，加入粒径为15～25μm的YAG：Ce3+荧光粉颗粒，继续球磨至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，然后将该粉末过筛造粒，得到热处理原料粉末。
称取适量的原料粉末装入石墨模具，在5MPa压强下进行压制成型，将氮化铝-荧光粉粉末连同石墨模具放入热压烧结炉内，在氮气气氛下烧结，烧结温度为1600℃，得到荧光陶瓷。
对比例一
称取粒径为5～10μm的氮化铝和0.05～0.1μm的Y2O3烧结助剂装入球磨罐中，添加适量的研磨溶剂(乙醇)、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨。待球磨罐内的浆料成粘稠悬浮状时，加入粒径为15～25μm的YAG：Ce3+荧光粉颗粒，继续球磨至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，然后将该粉末过筛造粒，得到热处理原料粉末。
称取适量的原料粉末装入石墨模具，在5MPa压强下进行压制成型，将氮化铝-荧光粉粉末连同石墨模具放入热压烧结炉内，在氮气气氛下烧结，发现在1600℃下难以烧结成型，将温度提高到1900℃，烧结得到荧光陶瓷，然而其气孔率高，在显微镜下能明显看到气孔。
对比例二
称取粒径为0.5～1μm的氮化铝，不加烧结助剂，装入球磨罐中，添加适量的研磨溶剂、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨。待球磨罐内的浆料成粘稠悬浮状时，加入粒径为15～25μm的YAG：Ce3+荧光粉颗粒，继续球磨至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，然后将该粉末过筛造粒，得到热处理原料粉末。
称取适量的原料粉末装入石墨模具，在5MPa压强下进行压制成型，将氮化铝-荧光粉粉末连同石墨模具放入热压烧结炉内，在氮气气氛下烧结，发现在1600℃下难以烧结成型，将温度提高到1750℃，得到荧光陶瓷。
将各个实施例、对比例得到的荧光陶瓷进行测试，获得荧光陶瓷的透光率、热导率数据及发光效率数据。其中，荧光陶瓷的发光效率通过 采用相同功率和波长的蓝光照射荧光陶瓷，并采用积分球收集，计算单位时间内荧光陶瓷发出的荧光与用于照射的蓝光的比值。
各实施例、对比例的数据对比见下表：
Figure PCTCN2017074957-appb-000001
实施例一与对比例一的区别在于，参与烧结的氮化铝的粒径不同，
实施例一的氮化铝为小粒径氮化铝，而对比例一的氮化铝为大粒径氮化铝。从表格数据及实验过程可以看出，采用小粒径氮化铝作为荧光陶瓷基质的原料，并在热处理步骤中对氮化铝-荧光粉粉末进行高压处理，可以大大降低热处理温度，并获得致密度高、荧光粉晶体形貌变化小的荧光陶瓷，该荧光陶瓷的透光率高(避免光吸收产热)、热导率高(快速散热)、发光效率高，适用于大功率激光照射发光的应用环境。
实施例一与对比例二的区别在于，实施例一添加了烧结助剂Y2O3，而对比例二没有添加烧结助剂。从实验过程及表格数据可以看出，通过添加烧结助剂，实施例一的热处理过程烧结温度在一定程度上得到降低，得到的荧光陶瓷的透光率也更好。可以推断，烧结助剂增强了粉料在烧结过程中的流动性，有助于净化晶界杂质，提高陶瓷的透光性能，从而减少光线吸收带来的热损耗。
本发明同样对其他烧结助剂如CaO、CaC2、La2O3或Dy2O3等进行对比测试，相对于不添加烧结助剂的技术方案，热处理温度都有不同程度的降低。
本发明还涉及用上述制备方法制备的氮化铝基质的荧光陶瓷，该荧光陶瓷包括基质氮化铝和被基质包裹的荧光粉，以及微量的烧结助剂，其中基质氮化铝呈连续分布状态，致密无气孔、热导率高，使得荧光粉发出的热量能够被迅速导出。而且氮化铝透明度高，不会对荧光粉发出的光形成阻挡。
虽然通过选择小粒径的氮化铝粉末，可以在一定程度上降低氮化铝 进入液相的温度。但是发明人在制备荧光陶瓷的过程中发现，虽然能够在不破坏荧光粉的情况下得到氮化铝基质的荧光陶瓷，然而若要使该荧光陶瓷具有良好的抗弯强度，仍需要尽量提高烧结热处理温度。因此，在荧光陶瓷的机械性能和发光性能之间，如何取舍成为难题。
发明人经过实验努力，发现可以将单一粒径的荧光粉替换成大粒径荧光粉与小粒径荧光粉组合的方式，使得在烧结热处理过程中，小粒径荧光粉进入液相，替代部分氮化铝与大粒径荧光粉结合。由于材料相同，小粒径荧光粉与大粒径荧光粉的结合力优于氮化铝与大粒径荧光粉的结合，从而在不提高烧结温度的情况下，促使制备得到的荧光陶瓷整体的机械性能(抗弯能力)提高，使得荧光陶瓷具有更好的可加工性。此外，将部分氮化铝替换为小粒径荧光粉，还增加了荧光陶瓷的发光密度。
为此，下面结合附图和实施方式对该实施例进行详细说明。
如图4为本发明实施例的荧光陶瓷的制备方法的流程图。如图所示，该制备方法依序包括以下步骤：
①混料：将氮化铝粉末、第一荧光粉、第二荧光粉与溶剂混合，得到氮化铝-荧光粉浆料，氮化铝的粒径为0.1～1μm，第一荧光粉的粒径为15～30μm，第二荧光粉的粒径为2～5μm；
②除杂：将氮化铝-荧光粉浆料干燥，然后将其在有氧气氛下煅烧，获得热处理原料粉末，即氮化铝-荧光粉粉末；
③热处理：将氮化铝-荧光粉粉末热处理，得到荧光陶瓷，其中，该氮化铝-荧光粉粉末在热处理前和/或热处理中经过5MPa以上高压处理，热处理温度为1500～1850℃，热处理在无氧气氛下进行。
在混料步骤中，首先是原料的选择，本实施例选用小粒径的超细氮化铝粉，粒径为0.1～1μm，第一荧光粉的粒径则远大于氮化铝，为15～30μm，第二荧光粉的粒径小于第一荧光粉的粒径，为2～5μm，第一荧光粉与第二荧光粉为材料相同的荧光粉。一般而言，荧光粉YAG：Ce3+的熔点为1970℃左右，而氮化铝的熔点为2200℃，在氮化铝进入液相之前，荧光粉的物理结构已经被破坏，这样的荧光粉即使再成型，其发光效率也将明显下降。本实施例采用微纳米级的氮化铝粉，可以大幅降低其进入液相的温度，使得氮化铝能够先于荧光粉进入液相，避免了荧 光粉物理结构的破坏。
本实施例中，荧光粉为YAG：Ce3+，也可以选择LuAG：Ce3+或YAG/LuAG掺杂其他镧系元素的荧光粉。
本实施例中，第一荧光粉占氮化铝和荧光粉粉末总量的质量百分比为45～67％。第一荧光粉作为发光中心，必须要有足够的量，才能保证荧光陶瓷发光强度，而且第一荧光粉的比重越高，越有利于荧光陶瓷最大发光强度的提高；但是，氮化铝作为基质，须达到足够的量才能保证连续分布，因此荧光粉不能过多。氮化铝占氮化铝和荧光粉粉末总量的质量百分比为28～45％。第二荧光粉占氮化铝和荧光粉粉末总量的质量百分比为5～10％，第二荧光粉的主要作用是填充第一荧光粉周围的空隙，并与第一荧光粉结合，同时承担小部分的发光作用，第一荧光粉的量较多，因此必要有足够的第二荧光粉与之结合；但是，由于小粒径的第二荧光粉的发光效率不高，因此不宜比重太大。
本实施例中，采用球磨的方式混料。首先称取一定量的氮化铝，装入球磨罐，添加适量的研磨溶剂(如乙醇)、增稠剂和分散剂，然后进行第一次球磨，得到粘稠悬浮状的浆料，再加入第二荧光粉，进行第二次球磨，再将第一荧光粉加入球磨罐，进行第三次球磨，最终得到氮化铝-荧光粉浆料。本实施例采用三步球磨的方法，使得粒径较小、不易分散均匀的氮化铝粉末能够先充分分散，然后再加入小粒径的第二荧光粉球磨，再加入大粒径的第一荧光粉球磨，主要考虑到越小的粒径的颗粒分散均匀的时间越长。第一次球磨的时间大于第二次球磨的时间大于第三次球磨的时间，避免了荧光粉过长时间的球磨，减少了该球磨过程对荧光粉的损害。
在除杂步骤中，该步骤的目的为将混料步骤中得到的氮化铝-荧光粉浆料中的研磨溶剂、增稠剂、分散剂等杂质除去，得到纯净的混合粉末。
本实施例中，首先对氮化铝-荧光粉浆料进行干燥，得到干粉，然后将干粉进行煅烧，使干粉中的有机成分分解、挥发。由于氮化铝和荧光粉的熔点高、热稳定性好，除去有机物的温度(一般在1000℃以下)不会对其的结构造成影响；在该温度下，氮化铝和荧光粉也不会氧化，因此可以在有氧气氛(如空气)下进行煅烧。
本实施例中，在热处理步骤之前，先对粉末进行造粒，将其转为颗粒大小为50～200μm的粉末。该造粒结果可以增加热处理过程中粉末的流动性，有利于热处理前后的高压成型，促使制备得到的荧光陶瓷致密而均匀。
在热处理步骤中，将得到的高纯度氮化铝-荧光粉粉末称取适量，装入石墨模具中，在5～40MPa下预压成型，然后将氮化铝-荧光粉粉末连同模具一同放入热压烧结炉中，在氮气气氛下高压烧结，烧结温度为1500～1750℃。该烧结温度下，氮化铝先进入液相，产生物相迁移，而后第二荧光粉至少部分进入液相，而第一荧光粉能够保持原有的晶体形貌，其发光强度不易受到影响。本实施例采用氮气气氛，对氮化铝产生保护作用，避免氮化铝与荧光粉中的氧结合生成氧化铝，提高了最终得到的荧光陶瓷的氮化铝纯度，保证了高热导率。
在本发明的另一个实施例中，热处理烧结在真空气氛下进行，该气氛下，更有利于原料内部的气体排除，减少闭孔气孔和开孔气孔的数量，有利于获得高致密度的烧结体，由于大量减少的了微型气孔的折射与散射效应，烧结体的透光性能也获得提高。
此外，热处理烧结过程也可以在氮气氢气混合气或者惰性气体(如氩气)中进行，避免氮化铝或荧光粉与热处理气氛反应。
在本发明的另一个实施例中，在热处理步骤中，将得到的高纯度氮化铝-荧光粉粉末称取适量，装入石墨模具中，在5～40MPa下预压成型，然后将氮化铝--荧光粉粉末连同模具一同放入放电等离子烧结炉中，在氮气气氛下高压烧结，烧结温度为1500～1750℃。该烧结过程中，晶粒间的放电及电离化产生局部高温，在粉末颗粒表面引起蒸发和融化，促进了荧光陶瓷致密化的过程，有效的降低了烧结温度。
在本发明的另一个实施例中，在热处理步骤中，将得到的高纯度氮化铝-荧光粉粉末称取适量，装入金属模具中，在5～40MPa下预压成型，然后再经过更高压强(150～300MPa)的冷等静压成型，将高压成型后的氮化铝-荧光粉粉末放入微波烧结炉，在氮气气氛下烧结，烧结温度为1600～1850℃。该烧结温度下，氮化铝进入液相，产生物相迁移；而后第二荧光粉部分进入液相，第一荧光粉能够保持原有的晶体形貌。本实 施例的冷等静压成型后微波烧结的方式，相较于热压烧结和放电等离子烧结，需要更高的温度，这是由于本方案在烧结过程中没有保持对氮化铝-荧光粉的持续加压，同等温度下反应剧烈程度相对较低。
在本发明的实施例中，经过热处理后得到的荧光陶瓷，还进一步包括对荧光陶瓷的还原处理步骤，该步骤在还原气氛下进行(如氮气/氢气混合气体)，该还原处理在略低于热处理烧结温度下进行，还原温度为1200～1650℃。该还原处理过程可以将热处理步骤中附着在荧光陶瓷上的杂质去除，避免杂质成为荧光陶瓷在工作环境下的产热中心而影响荧光陶瓷的使用。
在本发明的另一实施例中，在混料步骤中，还包括将烧结助剂加入溶剂均匀混合的步骤，其中，烧结助剂占荧光粉和氮化铝总质量的质量百分比为0.5～3％，烧结助剂包括Y2O3、CaO、CaC2、La2O3或Dy2O3中的至少一种。烧结助剂的量太少时作用不明显；但当烧结助剂的量过多，会限制氮化铝的生长，并产生氧化铝、铝钇酸盐的杂相，降低荧光陶瓷的热导率和透光性。烧结助剂能够降低氮化铝粉末的烧结温度，使氮化铝粉末更容易进入液相烧结，有利于提高发光陶瓷的致密度。烧结助剂在高温下的高流动性还有助于净化晶界杂质，减少光在经过晶界时发生的散射，有助于提高陶瓷的透光性能。
以下为不同条件下制备荧光陶瓷的各实施例对比，除杂、造粒等其他的条件相同。
实施例一
称取粒径为0.5～1μm的氮化铝装入球磨罐中，添加适量的研磨溶剂(乙醇)、增稠剂和陶瓷分散剂，再加入研磨体，进行球磨2h。待球磨罐内的浆料成粘稠悬浮状时，加入粒径为2-5μm的YAG：Ce3+荧光粉颗粒，继续球磨1h；然后加入粒径为15-20μm的YAG：Ce3+荧光粉颗粒，继续球磨0.5h至荧光粉分布均匀，结束球磨。
然后将浆料取出，真空恒温干燥得到干粉，将干粉在马弗炉中煅烧，除去干粉中的有机成分，然后将该粉末过筛造粒，得到热处理原料粉末。
称取适量的原料粉末装入石墨模具，在5MPa压强下进行压制成型，将氮化铝-荧光粉粉末连同石墨模具放入热压烧结炉内，在氮气气氛下烧 结，烧结温度为1600℃，得到荧光陶瓷。
对荧光陶瓷进行测试，测得荧光陶瓷的透光率为35％，热导率为60W/(m·K)，发光效率为62％。其中，通过采用蓝光照射荧光陶瓷，并采用积分球收集受激发荧光，计算单位时间内荧光陶瓷发出的荧光与用于照射的蓝光的比值，获得荧光陶瓷的发光效率。
将实施例一中的小粒径YAG：Ce3+荧光粉颗粒替换为同等质量的大粒径YAG：Ce3+荧光粉颗粒，依照同样实验条件制得荧光陶瓷，发现该荧光陶瓷的抗弯强度低于实施例一制得的荧光陶瓷。
本发明还涉及用上述制备方法制备的氮化铝基质的荧光陶瓷，该荧光陶瓷包括基质氮化铝和被基质包裹的荧光粉，其中基质氮化铝呈连续分布状态，致密无气孔、热导率高，使得荧光粉发出的热量能够被迅速导出。而且氮化铝透明度高，不会对荧光粉发出的光形成阻挡。
本说明书中各个实施例之间相同相似部分互相参见即可。
以上所述仅为本发明的实施方式，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本发明的专利保护范围内。

Claims (16)

  1. 一种氮化铝基质的荧光陶瓷的制备方法，其特征在于，依序包括以下步骤：
    混料：将原料与溶剂均匀混合，所述原料至少包括氮化铝粉末和荧光粉，得到浆料，所述氮化铝粉末的粒径为0.1～1μm，所述荧光粉至少包括粒径为10～30μm的第一荧光粉；
    除杂：将所述浆料干燥，然后将其在有氧气氛下煅烧，除去其中的水和有机物，获得含有氮化铝和荧光粉的热处理原料粉末；
    热处理：将所述热处理原料粉末热处理，得到荧光陶瓷，其中，该热处理原料粉末在热处理前和/或热处理中经过5MPa以上高压处理，使所述热处理原料粉末保持致密，热处理温度为1500～1850℃，热处理在无氧气氛下进行。
  2. 根据权利要求1所述的制备方法，其特征在于，所述荧光粉包括YAG：Ce3+或LuAG：Ce3+。
  3. 根据权利要求1所述的制备方法，其特征在于，所述荧光粉占所述热处理原料粉末的质量百分比为15～90％。
  4. 根据权利要求1所述的制备方法，其特征在于，所述混料步骤中，所述原料还包括烧结助剂，所述烧结助剂的粒径为0.05～1μm。
  5. 根据权利要求4所述的制备方法，其特征在于，所述烧结助剂包括Y2O3、CaO、CaC2、La2O3或Dy2O3。
  6. 根据权利要求4所述的制备方法，其特征在于，所述荧光粉占所述氮化铝粉末、烧结助剂和荧光粉总量的质量百分比为30～80％，所述氮化铝占所述氮化铝粉末、烧结助剂和荧光粉总量的质量百分比为17～69.5％，所述烧结助剂占所述氮化铝粉末、烧结助剂和荧光粉总量的质量百分比为0.5～3％。
  7. 根据权利要求1所述的制备方法，其特征在于，所述混料步骤中，所述第一荧光粉粒径为15～30μm，所述荧光粉还包括第二荧光粉，粒径为2～5μm，第一荧光粉与第二荧光粉为材料相同的荧光粉，且第一荧光粉多于第二荧光粉。
  8. 根据权利要求7所述的制备方法，其特征在于，所述第一荧光粉占所述氮化铝粉末和荧光粉总量的质量百分比为45～67％，所述第二荧光粉占所述氮化铝粉末和荧光粉总量的质量百分比为5～10％，所述氮化铝占所述氮化铝粉末和荧光粉总量的质量百分比为28～45％。
  9. 根据权利要求7所述的制备方法，其特征在于，所述原料还包括增稠剂和陶瓷分散剂，所述混料步骤包括，首先将除所述荧光粉以外的其他原料与所述研磨容积装入球磨罐混合后进行第一次球磨；然后将所述第二荧光粉加入球磨罐，进行第二次球磨；再将所述第一荧光粉加入球磨罐，进行第三次球磨；其中，第一次球磨时间大于第二次球磨时间大于第三次球磨时间。
  10. 根据权利要求1至8任一项所述的制备方法，其特征在于，所述混料步骤中，所述原料还包括增稠剂和陶瓷分散剂，所述混料步骤还包括将所述原料与溶剂混合后球磨。
  11. 根据权利要求10所述的制备方法，其特征在于，所述混料步骤包括，首先将除所述荧光粉以外的其他原料与所述溶剂装入球磨罐混合后进行第一次球磨，然后再将所述荧光粉加入球磨罐，进行第二次球磨，其中，第一次球磨时间大于第二次球磨时间。
  12. 根据权利要求1所述的制备方法，其特征在于，在所述热处理步骤前，包括将所述粉末造粒的步骤，得到颗粒大小为50～200μm的粉末。
  13. 根据权利要求1所述的制备方法，其特征在于，所述热处理步骤包括，将所述热处理原料粉末在模具中5～40MPa一次高压成型，然后在150～300MPa冷等静压二次高压成型，取下模具，再将高压成型后的符合粉末放入微波烧结炉，在1600～1850℃进行热处理烧结。
  14. 根据权利要求1所述的制备方法，其特征在于，所述热处理步骤包括，将所述符合粉末在模具中5～40MPa高压预成型，然后将所述符合粉末连同模具一同放入热压烧结炉或放电等离子烧结炉中，在1500～1750℃进行热处理烧结。
  15. 根据权利要求13或14任一项所述的制备方法，其特征在于，在烧结步骤后，还包括对荧光陶瓷的还原处理步骤，该还原处理步骤在 还原气氛下进行，且还原处理步骤的温度环境为1200～1650℃。
  16. 一种荧光陶瓷，其特征在于，该荧光陶瓷由权利要求1～15中任一项所述的制备方法制备。
PCT/CN2017/074957 2016-03-18 2017-02-27 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷 Ceased WO2017157157A1 (zh)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
CN201610160983.4 2016-03-18
CN201610156483.3 2016-03-18
CN201610156064.X 2016-03-18
CN201610160983.4A CN107200589B (zh) 2016-03-18 2016-03-18 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
CN201610156064.XA CN107200587B (zh) 2016-03-18 2016-03-18 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
CN201610156483.3A CN107200588B (zh) 2016-03-18 2016-03-18 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷

Publications (1)

Publication Number Publication Date
WO2017157157A1 true WO2017157157A1 (zh) 2017-09-21

Family

ID=59851917

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2017/074957 Ceased WO2017157157A1 (zh) 2016-03-18 2017-02-27 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷

Country Status (1)

Country Link
WO (1) WO2017157157A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112321155A (zh) * 2020-11-06 2021-02-05 焦作市吉成磁电有限公司 激光照明组件及其制造方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102173774A (zh) * 2011-01-28 2011-09-07 中国科学院上海光学精密机械研究所 掺铈铽钇石榴石透明陶瓷荧光材料及其制备方法
CN102249660A (zh) * 2011-04-22 2011-11-23 中国科学院上海光学精密机械研究所 GaInN白光LED用复合结构荧光陶瓷及其制备方法
CN102352245A (zh) * 2011-09-06 2012-02-15 西安交通大学 一种Eu掺杂氮化铝基荧光粉的制备方法
CN102517017A (zh) * 2011-12-09 2012-06-27 苏州晶能科技有限公司 荧光粉及其制备方法和含该荧光粉的白光led平面光源
US20140054500A1 (en) * 2010-08-31 2014-02-27 Kabushiki Kaisha Toshiba Process for production of fluorescent substance
CN104291796A (zh) * 2014-09-23 2015-01-21 上海三思电子工程有限公司 一种led用透明荧光陶瓷的制备方法
CN104844217A (zh) * 2015-04-01 2015-08-19 苏州工业园区晶冠瓷材料科技有限公司 一种用于暖色温白光LED封装光源的AlON透明陶瓷荧光体的制备方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140054500A1 (en) * 2010-08-31 2014-02-27 Kabushiki Kaisha Toshiba Process for production of fluorescent substance
CN102173774A (zh) * 2011-01-28 2011-09-07 中国科学院上海光学精密机械研究所 掺铈铽钇石榴石透明陶瓷荧光材料及其制备方法
CN102249660A (zh) * 2011-04-22 2011-11-23 中国科学院上海光学精密机械研究所 GaInN白光LED用复合结构荧光陶瓷及其制备方法
CN102352245A (zh) * 2011-09-06 2012-02-15 西安交通大学 一种Eu掺杂氮化铝基荧光粉的制备方法
CN102517017A (zh) * 2011-12-09 2012-06-27 苏州晶能科技有限公司 荧光粉及其制备方法和含该荧光粉的白光led平面光源
CN104291796A (zh) * 2014-09-23 2015-01-21 上海三思电子工程有限公司 一种led用透明荧光陶瓷的制备方法
CN104844217A (zh) * 2015-04-01 2015-08-19 苏州工业园区晶冠瓷材料科技有限公司 一种用于暖色温白光LED封装光源的AlON透明陶瓷荧光体的制备方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112321155A (zh) * 2020-11-06 2021-02-05 焦作市吉成磁电有限公司 激光照明组件及其制造方法

Similar Documents

Publication Publication Date Title
CN107285745B (zh) 一种氧化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
CN107200588B (zh) 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
CN107285746B (zh) 一种氧化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
JP6834491B2 (ja) 焼結蛍光体、発光装置、照明装置、車両前照灯、及び焼結蛍光体の製造方法
CN109896852B (zh) 用于蓝光激发的白光照明的复相荧光陶瓷、制备方法及光源装置
CN112441817B (zh) 荧光陶瓷及其制备方法、光源装置
Zhu et al. Additive-free Y2O3: Eu3+ red-emitting transparent ceramic with superior thermal conductivity for high-power UV LEDs and UV LDs
CN107200589B (zh) 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
CN109467453A (zh) 一种具有特征微观结构的荧光陶瓷及其制备方法和应用
CN108530071A (zh) 一种yag荧光陶瓷及其制备方法和应用
CN106653652A (zh) 半导体制造装置用部件、其制法以及附带有轴的加热器
WO2018205710A1 (zh) 一种荧光复合陶瓷及其制备方法和应用
CN112174646A (zh) 一种激光照明用高导热荧光陶瓷及其制备方法
CN110240468A (zh) 荧光陶瓷及其制备方法
US7081425B2 (en) Aluminum nitride sintered body
CN111196730B (zh) 一种高热导率氮化硅陶瓷材料及其制备方法
CN111995398A (zh) 一种用于高显指激光照明的荧光陶瓷及其制备方法
CN111517804A (zh) 一种氮化物红色复相荧光陶瓷及其制备方法
CN107200587B (zh) 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
CN1076012C (zh) 透明氮化铝陶瓷的制备方法
JP4783560B2 (ja) 窒化アルミニウム焼結体及びその製造方法
JP5144095B2 (ja) 窒化アルミニウム焼結体およびその製造方法
WO2017157157A1 (zh) 一种氮化铝基质的荧光陶瓷的制备方法及相关荧光陶瓷
US12146085B2 (en) Multiphase fluorescent ceramic and preparation method thereof
CN119191873A (zh) 一种荧光陶瓷及其制备方法、波长转换装置和发光装置

Legal Events

Date Code Title Description
NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17765699

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17765699

Country of ref document: EP

Kind code of ref document: A1