A kind of preparation method and fluorescence associated ceramics of the fluorescence ceramics of alumina host
Technical field
The present invention relates to fluorescence ceramics field, more particularly to a kind of fluorescence ceramics of alumina host
Preparation method and fluorescence associated ceramics.
Background technology
Blue laser excites the technology of fluorescent material acquisition visible ray, with the hair of laser display technology
Exhibition is constantly paid attention to, characteristic of the research general orientation currently primarily directed to LASER Excited Fluorescence powder
To develop new fluorescent material (material for transformation of wave length), main requirement is luminosity height, energy
Enough bear the features such as high power laser illumination, optical conversion efficiencies are high, heat conductivility is high.
Traditional fluorescence ceramics are developed mainly for the LED characteristics of luminescence, due to LED chip
Power is smaller, and the blue power density sent is relatively low, therefore for the LED luminescent ceramics developed
Luminous efficiency does not obtain enough attention.Such as common YAG fluorescence ceramics are main by original
Feed powder end Al2O3、Y2O3、CeO2Tabletted under forcing press after calcining, then sintering is obtained
Fluorescence ceramics.Because fluorescence ceramics typically cover LED surface, certain light transmission need to be pursued,
Therefore YAG fluorescence ceramics compare deviation light transmittance performance, and crystal grain-growth degree therein is relatively low,
Cause its luminosity relatively low.In addition, the thermal conductivity of traditional YAG ceramics is relatively low,
Generally 10~14W/ (mK), with the development of LASER Light Source technology, light source power is increasing,
It is required that light-converting material has higher thermal conductivity, what is produced during can converting light into is a large amount of
Heat is rapidly passed.
Therefore, it is a kind of to obtain high heat conductance, the preparation method of the fluorescence ceramics of high-luminous-efficiency urgently
Exploitation.
The content of the invention
For the above-mentioned fluorescence ceramics thermal conductivity in the prior art, prepared is low, luminous efficiency is low
Defect, the present invention provide it is a kind of acquisition high heat conductance, the preparation of the fluorescence ceramics of high-luminous-efficiency
Method, sequentially comprises the following steps:
Batch mixing:Aluminum oxide, fluorescent material, sintering aid are uniformly mixed with abrasive solvents, obtain glimmering
Light ceramic precursor pulp, the particle diameter of aluminum oxide is 0.05~1 μm, and fluorescent material is YAG doped lanthanums
The fluorescent material or LuAG of series elements adulterate the fluorescent material of lanthanide series, and the particle diameter of fluorescent material is
10~30 μm, sintering aid is magnesia-yittrium oxide mixed sintering auxiliary agent, and the particle diameter of sintering aid is
0.05~0.1 μm;Calcining:Fluorescence ceramics precursor pulp is dried, it is then being had into oxygen atmosphere
Lower calcining, removes water therein and organic matter, obtains fluorescence ceramics precursor powder;Sintering:Will
Fluorescence ceramics precursor powder is sintered, and obtains fluorescence ceramics, and sintering temperature is 1250~1550 DEG C,
Sintering pressure is 30~200MPa, is sintered under oxygen-free atmosphere and carries out, wherein, before the fluorescence ceramics
Drive body powder and pass through more than 5MPa pre-press before sintering, powder is kept fine and close.
Preferably, fluorescent material includes YAG:Ce3+Or LuAG:Ce3+。
Preferably, the mass percent that fluorescent material accounts for fluorescence ceramics precursor powder total amount is
30~80%, the mass percent that sintering aid accounts for fluorescence ceramics precursor powder total amount is
0.01~1%.
Preferably, batch mixing step includes, and aluminum oxide and sintering aid are loaded into ball grinder first, plus
Enter abrasive solvents, thickener and dispersant, carry out first time ball milling;Then fluorescent material is added into ball
Grinding jar, carries out second of ball milling, wherein, first time Ball-milling Time is more than second of Ball-milling Time.
Preferably, in calcining step, calcining heat is 500~650 DEG C.
Preferably, in sintering step, oxygen-free atmosphere be nitrogen, hydrogen, nitrogen hydrogen mixed gas,
Inert gas or vacuum atmosphere.
Preferably, sintering step includes, by fluorescence ceramics precursor powder 5~15MPa in a mold
High pressure is preforming, and fluorescence ceramics precursor powder is together then put into hot-pressed sintering furnace together with mould
In, fluorescence ceramics precursor powder is sintered under 30~200MPa.
Preferably, sintering step includes, by fluorescence ceramics precursor powder 5~15MPa in a mold
High pressure is preforming, and fluorescence ceramics precursor powder is together then put into plasma discharging together with mould
In sintering furnace, fluorescence ceramics precursor powder is sintered under 30~200MPa, be sintered in vacuum gas
Carried out under atmosphere.
Preferably, after a sintering step, should be also in addition to the reduction treatment step of fluorescence ceramics
Former process step is carried out under reducing atmosphere, and the temperature environment of reduction treatment step is
1100~1700 DEG C.
Present invention also offers a kind of fluorescence ceramics, the fluorescence ceramics are by above-mentioned preparation method system
It is standby.
Compared with prior art, the present invention includes following beneficial effect:
The present invention is by by oxygen that magnesia-yittrium oxide mixed sintering auxiliary agent and particle diameter are 0.05~1 μm
Change the fluorescent material or LuAG doped lanthanums of aluminium, particle diameter for 10~30 μm of YAG doping lanthanide series
The fluorescent material mixing of series elements, 30~200MPa high pressure combustions are carried out by powder at 1250~1550 DEG C
Knot, so as to obtain fluorescence ceramics.In technical solution of the present invention, the selection of alumina particle and high pressure
Processing procedure causes aluminum oxide to be able to enter liquid phase at a lower temperature, and magnesia-yittrium oxide mixing is burnt
The presence of knot auxiliary agent causes the temperature that aluminum oxide enters liquid phase further to reduce, and at this temperature,
The sintering aid will not produce destroying infection to the fluorescent material of selected particle diameter, can holding surface
Pattern is basically unchanged so that the fluorescence ceramics after shaping can retain the luminescent properties of former fluorescent material;
Simultaneously as small particle is have selected, and under the synergy of HIGH PRESSURE TREATMENT, fluorescence ceramics forerunner
Body powder can keep the fine and close, state of low porosity afterwards before sintering, greatly improve fluorescence
The heat conductivility of ceramics, so as to prepare high heat conductance, the fluorescence ceramics of high-luminous-efficiency.
Brief description of the drawings
Fig. 1 is the flow chart of the preparation method of the fluorescence ceramics of the embodiment of the present invention;
Embodiment
As described in background, the preparation of fluorescence ceramics of the prior art passes through fluorescent material is former
Expect that (i.e. each type oxide) sintering is made, its translucency there are certain requirements, what is so obtained is glimmering
Light ceramic, luminous efficiency is significantly lower than the phosphor powder that same raw material is prepared, and YAG
The thermal conductivity of ceramics is low, very unfavorable for the radiating during use.The present invention prepares aluminum oxide
The fluorescence ceramics of matrix, directly using existing commercial fluorescent material as raw material, in preparation process
Prepared by fluorescent material the step of is not suffered from, it is to avoid fluorescent material Growing Process of Crystal Particles in prepared by fluorescence ceramics
The various problems brought, while with by selecting the aluminum oxide of small particle and coordinating high pressure-treated
Journey so that the alumina host of obtained fluorescence ceramics is fine and close, high heat conduction, finished product has good
Heat dispersion.
Because the fusing point of fluorescent material and aluminum oxide is approached, and slightly below fusing point (such as YAG of aluminum oxide
Fusing point be 1950 DEG C, the fusing point of aluminum oxide is 2050 DEG C), in preparation process, work as aluminum oxide
During into liquid phase, the original structure of fluorescent material is easily destroyed, the alumina host so obtained
Fluorescence ceramics luminous efficiency it is low.In the present invention, by select appropriate particle size alumina powder and
Fluorescent material so that the particle diameter of alumina powder is much smaller than fluorescent material, reduces aluminum oxide and enters liquid phase
Required temperature, the temperature of liquid phase is entered without reducing fluorescent material, it is ensured that fluorescent material is in sintering temperature
It can keep physical arrangement stable under degree, fluorescent material is possessed the light efficiency occurred frequently of big particle diameter fluorescent material
Rate.In addition, alumina particle is small so that the HIGH PRESSURE TREATMENT in preparation process can be sufficient filling with glimmering
Hole in light ceramic, the consistency for improving obtained fluorescence ceramics (and then improves heat conductivility
And light transmission).Burnt in addition, the present invention introduces magnesia-yittrium oxide mixing in preparation process
Auxiliary agent is tied, the sintering aid takes the lead in entering liquid phase in sintering process, and promotes aluminum oxide lower
At a temperature of enter liquid phase, serve the effect of acceleration of sintering, not only increase sintered body heat conduction and
Light transmission, while also ensuring fluorescent material as much as possible in sintering process not by too high
The influence of temperature, is maintained physical arrangement, surface topography stabilization, so that obtained fluorescence
Ceramics possess good luminous efficiency.The refractive index of magnesia-yittrium oxide mixed sintering auxiliary agent and oxidation
Aluminium is approached, and can reduce light scattering loss of the light in fluorescence ceramics, is favorably improved the saturating of ceramics
Optical property.And the sintering aid will not be damaged to the surface topography of fluorescent material.
The characteristics of present invention is different from the technical scheme for preparing single aluminium oxide ceramics is, sinters
Auxiliary agent, the selection of the particle diameter of each component must account for the influence to fluorescent material, while considering fluorescence
Reaction of the powder to aluminum oxide, sintering aid so that in sintering process, does not influence glimmering as far as possible
In the case of light powder so that aluminum oxide enters liquid phase, the parcel to big particle diameter fluorescent material is formed.
The embodiment of the present invention is described in detail with embodiment below in conjunction with the accompanying drawings.
Particle diameter of the present invention, refers to median D50.
Such as flow charts of the Fig. 1 for the preparation method of the fluorescence ceramics of the embodiment of the present invention.As illustrated,
The preparation method sequentially comprises the following steps:
1. batch mixing:Aluminum oxide, fluorescent material, sintering aid are uniformly mixed with abrasive solvents, obtained
Fluorescence ceramics precursor pulp, sintering aid is magnesia-yittrium oxide mixed sintering auxiliary agent, and sintering is helped
The particle diameter of agent is 0.05~0.1 μm;
2. calcine:Fluorescence ceramics precursor pulp is dried, then calcined it in the case where there is oxygen atmosphere,
Water therein and organic matter are removed, fluorescence ceramics precursor powder is obtained;
3. sinter:Fluorescence ceramics precursor powder is sintered, fluorescence ceramics are obtained, sintering temperature is
1250~1550 DEG C, sintering pressure is 30~200MPa, is sintered under oxygen-free atmosphere and carries out, wherein,
The fluorescence ceramics precursor powder passes through more than 5MPa pre-press before sintering.
It is the selection of raw material first in batch mixing step, the present embodiment selects the ultra-fine oxygen of small particle
Change aluminium powder, particle diameter is 0.05~1 μm, it is furthermore preferred that the alumina powder of 0.06~0.2 μm of selection;
The particle diameter of fluorescent material is then much larger than aluminum oxide, is 10~30 μm.In general, fluorescent material YAG:Ce3+
Fusing point be 1970 DEG C or so, and the fusing point of aluminum oxide be 2050 DEG C, enter liquid phase in aluminum oxide
Before, the physical arrangement of fluorescent material has been destroyed, even if such fluorescent material reshaping, and it is sent out
Light efficiency will be also decreased obviously.The present embodiment uses nano level alumina powder, can be greatly reduced
It enters the temperature of liquid phase so that aluminum oxide can enter liquid phase prior to fluorescent material, it is to avoid fluorescence
The destruction of powder physical arrangement.In the present embodiment, fluorescent material is YAG:Ce3+, can also select
LuAG:Ce3+, YAG doping lanthanide series fluorescent material or LuAG adulterate other lanthanide series
Fluorescent material.Sintering aid selects magnesia-yittrium oxide mixed sintering auxiliary agent, it is demonstrated experimentally that this burn
Knot auxiliary agent is acted to the surface of aluminum oxide, the surface topography without influenceing fluorescent material.
In the present embodiment, the mass percent that fluorescent material accounts for fluorescence ceramics precursor powder total amount is
30~80%.Fluorescent material is used as the centre of luminescence, it is necessary to has enough amounts, just can guarantee that fluorescence ceramics
Luminous intensity, and the proportion of fluorescent material is higher, is more conducive to fluorescence ceramics maximum emission intensity
Improve;But, aluminum oxide must reach that enough amounts just can guarantee that continuously distributed as matrix, because
This fluorescent material can not be excessive.The mass percent that sintering aid accounts for powder total amount is 0.01~1%, is burnt
Effect is not obvious when tying the amount of auxiliary agent very little;But the amount for working as sintering aid is excessive, during more than 1wt%,
The growth of aluminum oxide can be limited, and produces dephasign, the thermal conductivity and translucency of fluorescence ceramics is reduced.
In the present embodiment, mixed by the way of ball milling.A certain amount of alumina powder is weighed first,
Load ball grinder, add appropriate abrasive solvents (such as ethanol), thickener and dispersant, then
First time ball milling is carried out, the slurry of sticky suspension is obtained, fluorescent material is added, carried out second
Ball milling, finally gives fluorescence ceramics precursor pulp.The method that the present embodiment uses two step ball millings,
First time Ball-milling Time is more than second of Ball-milling Time so that particle diameter is smaller, it is finely dispersed to be difficult
Alumina powder can be first fully dispersed, then add fluorescent powder ball-milling, it is to avoid fluorescent material is long
The ball milling of time, reduces infringement of the mechanical milling process to fluorescent material.
In calcining step, the purpose of the step is the grinding in the slurry that will be obtained in batch mixing step
The impurity such as solvent, thickener, dispersant are removed, and obtain high-purity fluorescence ceramics precursor powder.
In the present embodiment, fluorescence ceramics precursor pulp is dried first, dry powder is obtained, so
Dry powder is calcined afterwards, the organic principle in dry powder decomposed, volatilized.Due to aluminum oxide and glimmering
The fusing point of light powder is high, heat endurance is good, removes the temperature of organic matter (typically below 1000 DEG C)
The structure of aluminum oxide and fluorescent material will not be impacted;In the present embodiment, calcining heat is
500~650 DEG C, at such a temperature, aluminum oxide and fluorescent material will not also be aoxidized, therefore can had
Calcined under oxygen atmosphere (such as air).
In the present embodiment, before the sintering step, first fluorescence ceramics precursor powder is granulated,
Switched to the powder that granular size is 50~200 μm.The granulation result can increase sintering process
The mobility of middle powder, is conducive to the high-pressure molding before and after sintering, promotes the fluorescence prepared to make pottery
Porcelain is fine and close and uniform.
In sintering step, obtained high-purity fluorescence ceramics precursor powder is weighed in right amount, dress
Enter in graphite jig, then the pre-molding under 5~15MPa connects fluorescence ceramics precursor powder
Together it is put into mould in hot-pressed sintering furnace, makes fluorescence ceramics precursor powder in 30~200MPa
Lower sintering (mould that is applied through of pressure passes to fluorescence ceramics precursor powder), is sintered in argon
Under gas atmosphere, sintering temperature is 1250~1550 DEG C.Under the sintering temperature, sintering aid rate is advanced
Enter liquid phase, and promote aluminum oxide to enter liquid phase, generation is mutually migrated;And fluorescent material does not enter or very
Enter liquid phase on a small quantity, only produce indivisible thing and mutually migrate so that fluorescent material can keep original
Crystal morphology, its luminous intensity is not easily susceptible to influence.
In another embodiment of the present invention, it is sintered under vacuum atmosphere and carries out, under the atmosphere,
It is more beneficial for the gas inside raw material to exclude, reduces the quantity of closed pore stomata and perforate stomata, favorably
In the sintered body for obtaining high-compactness, because the refraction of the miniature stomata largely reduced is imitated with scattering
Should, the light transmission of sintered body is also improved.
In addition, sintering process can also be in other inert gases or nitrogen, hydrogen, nitrogen and hydrogen mixture
It is middle to carry out, it is to avoid aluminum oxide or fluorescent material react with atmosphere.
In another embodiment of the present invention, in sintering step, by obtained high-purity fluorescence
Ceramic forerunner powder is weighed in right amount, is fitted into graphite jig, the pre-molding under 5~15MPa,
Then powder is together put into discharge plasma sintering stove together with mould, makes fluorescence ceramics presoma
Powder sinters that (mould that is applied through of pressure passes to fluorescence ceramics presoma under 30~200MPa
Powder), sintering is carried out under vacuo, and sintering temperature is 1250~1550 DEG C.In the sintering process,
Intercrystalline electric discharge and ionization produce localized hyperthermia, cause evaporation in powder particle surface and melt
Change, promote the process of fluorescence ceramics densification, effectively reduce sintering temperature.
In the present embodiment, the preferred heating rate of heat treatment sintering process is 30~200 DEG C/min
(according to the heating ability of each agglomerating plant), due to the calcining step and HIGH PRESSURE TREATMENT before sintering,
, will not be because of so that fluorescence ceramics precursor powder keeps interior solid imporosity in temperature-rise period
Heating rate is fast and volume substantially expands so that product fluorescence ceramics ftracture.Meanwhile, quickly heating
Speed causes fluorescence ceramics presoma to avoid the side reaction brought that heats up for a long time (such as with surrounding
Reaction inside the reaction of environment and fluorescent material), it is ensured that fluorescence ceramics have good printing opacity
Property, thermal conductivity and luminescent properties.In the present invention, because sintering process relates generally to physical change,
Influence of the quick heating rate to it is not as big in the reaction of other chemicals.
In an embodiment of the present invention, the fluorescence ceramics obtained after oversintering, are still further comprised
To the reduction treatment step of fluorescence ceramics, the step carry out under reducing atmosphere (such as nitrogen/hydrogen mix
Close gas), the reduction treatment is carried out under slightly below heat treatment sintering temperature, and reduction temperature is
1100~1700 DEG C.The reduction treatment process will can be attached on fluorescence ceramics in sintering step
Impurity is removed, it is to avoid impurity turns into heat production center of the fluorescence ceramics under working environment and influences fluorescence
The use of ceramics.
Contrasted below to prepare each embodiment of fluorescence ceramics under different condition.
Embodiment one
Raw material selects high-purity superfine aluminium oxide nano powder, and powder diameter is 0.08-0.2 μm, choosing
With high-purity superfine nano yttrium oxide powder, particle diameter is 0.05-0.1 μm, is received from high-purity superfine
Rice magnesium oxide powder, particle diameter is 0.05-0.1 μm, from YAG:Ce3+Fluorescent material, particle diameter is
15-20μm。
Weigh a number of alumina powder (39.9wt%), yttrium oxide powder (0.05wt%),
Magnesium oxide powder (0.05wt%) and YAG:Ce3+Phosphor powder (60wt%).By alumina powder
End, yttrium oxide powder and magnesium oxide powder are fitted into polytetrafluoroethylene (PTFE) ball grinder, add appropriate second
Alcohol adds appropriate ceramic dispersants as dispersant, with ultralow mill mistake rate as abrasive solvents
Zirconia ball carries out first time ball milling, and Ball-milling Time is 5h.
After first time ball milling terminates, YAG is added:Ce3+Fluorescent material is carried out second into ball grinder
Ball milling, Ball-milling Time is 20min.
After ball milling terminates twice, dried using vacuum constant temperature and obtain dry powder.
Dry powder carries out 500 DEG C of calcining in Muffle furnace, removes the organic principle in powder, time
For 2 hours.Powder sieving granulation after calcining, obtains the fluorescence ceramics precursor of high fluidity
End.
Weigh appropriate fluorescence ceramics precursor powder to be fitted into graphite jig, enter under 5MPa pressure
Row is pre-stamped, and then graphite jig is put into hot-pressed sintering furnace, sintered under an argon atmosphere, burns
1250 DEG C of junction temperature, is incubated 8h, sintering pressure is 200MPa.After the completion of sintering, removal pressure
And furnace cooling, obtain the fluorescence ceramics composite of alumina host.
Embodiment two
Raw material selects high-purity superfine aluminium oxide nano powder, and powder diameter is 0.08-0.2 μm, choosing
With high-purity superfine nano yttrium oxide powder, particle diameter is 0.05-0.1 μm, is received from high-purity superfine
Rice magnesium oxide powder, particle diameter is 0.05-0.1 μm, from YAG:Ce3+Fluorescent material, particle diameter is
15-20μm。
Weigh a number of alumina powder (30wt%), yttrium oxide powder (0.5wt%), oxygen
Change magnesium dust (0.5wt%) and YAG:Ce3+Phosphor powder (69wt%).By alumina powder,
Yttrium oxide powder and magnesium oxide powder are fitted into polytetrafluoroethylene (PTFE) ball grinder, add appropriate ethanol and make
For abrasive solvents, appropriate ceramic dispersants are added as dispersant, with the oxidation of ultralow mill mistake rate
Zirconium ball carries out first time ball milling, and Ball-milling Time is 24h.
After first time ball milling terminates, YAG is added:Ce3+Fluorescent material is carried out second into ball grinder
Ball milling, Ball-milling Time is 40min.
After ball milling terminates twice, dried using vacuum constant temperature and obtain dry powder.
Dry powder carries out 600 DEG C of calcining in Muffle furnace, removes the organic principle in powder, time
For 2 hours.Powder sieving granulation after calcining, obtains the fluorescence ceramics precursor of high fluidity
End.
Weigh appropriate fluorescence ceramics precursor powder to be fitted into graphite jig, enter under 15MPa pressure
Row is pre-stamped, and then graphite jig is put into discharge plasma sintering stove, sintered under vacuo,
1450 DEG C of sintering temperature, is incubated 2h, sintering pressure is 40MPa.After the completion of sintering, removal pressure
Power and furnace cooling, obtain the fluorescence ceramics composite of alumina host.
Embodiment three
Raw material selects high-purity superfine aluminium oxide nano powder, and powder diameter is 0.08-0.2 μm, choosing
With high-purity superfine nano yttrium oxide powder, particle diameter is 0.05-0.1 μm, is received from high-purity superfine
Rice magnesium oxide powder, particle diameter is 0.05-0.1 μm, from LuAG:Ce3+Fluorescent material, particle diameter is
15-20μm。
Weigh a number of alumina powder (30wt%), yttrium oxide powder (0.5wt%), oxygen
Change magnesium dust (0.5wt%) and YAG:Ce3+Phosphor powder (69wt%).By alumina powder,
Yttrium oxide powder and magnesium oxide powder are fitted into polytetrafluoroethylene (PTFE) ball grinder, add appropriate ethanol and make
For abrasive solvents, appropriate ceramic dispersants are added as dispersant, with the oxidation of ultralow mill mistake rate
Zirconium ball carries out first time ball milling, and Ball-milling Time is 24h.
After first time ball milling terminates, YAG is added:Ce3+Fluorescent material is carried out second into ball grinder
Ball milling, Ball-milling Time is 50min.
After ball milling terminates twice, dried using vacuum constant temperature and obtain dry powder.
Dry powder carries out 650 DEG C of calcining in Muffle furnace, removes the organic principle in powder, time
For 3 hours.Powder sieving granulation after calcining, obtains the fluorescence ceramics precursor of high fluidity
End.
Weigh appropriate fluorescence ceramics precursor powder to be fitted into graphite jig, enter under 10MPa pressure
Row is pre-stamped, and then graphite jig is put into discharge plasma sintering stove, sintered under vacuo,
1450 DEG C of sintering temperature, is incubated 3h, sintering pressure is 50MPa.After the completion of sintering, removal pressure
Power and furnace cooling, obtain the fluorescence ceramics composite of alumina host.
The invention further relates to the fluorescence ceramics of the alumina host prepared with above-mentioned preparation method, this is glimmering
Light ceramic includes matrix alumina and the fluorescent material wrapped up by matrix, and micro sintering aid,
Wherein matrix alumina is in continuously distributed state, and fine and close pore-free, thermal conductivity are high so that fluorescent material
The heat sent can be exported rapidly.And aluminum oxide transparency is high, sintering aid and aluminum oxide
Refractive index approach, the light scattering for aoxidizing aluminium surface is few, the formation resistance of the light that will not be sent to fluorescent material
Gear.
Between the embodiment of each in this specification identical similar portion mutually referring to.
Embodiments of the present invention are the foregoing is only, the patent model of the present invention is not thereby limited
Enclose, the equivalent structure or equivalent process that every utilization description of the invention and accompanying drawing content are made become
Change, or be directly or indirectly used in other related technical fields, be similarly included in the present invention's
In scope of patent protection.