EP2652079A1 - Composition containing a core-shell aluminate, phosphor obtained from said composition, and preparation methods - Google Patents
Composition containing a core-shell aluminate, phosphor obtained from said composition, and preparation methodsInfo
- Publication number
- EP2652079A1 EP2652079A1 EP11781538.1A EP11781538A EP2652079A1 EP 2652079 A1 EP2652079 A1 EP 2652079A1 EP 11781538 A EP11781538 A EP 11781538A EP 2652079 A1 EP2652079 A1 EP 2652079A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- core
- phosphor
- aluminate
- shell
- composition
- 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.)
- Withdrawn
Links
- 239000000203 mixture Substances 0.000 title claims abstract description 50
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title claims abstract description 26
- 150000004645 aluminates Chemical class 0.000 title claims abstract description 17
- 238000002360 preparation method Methods 0.000 title description 10
- 239000011258 core-shell material Substances 0.000 title description 2
- 229910052771 Terbium Inorganic materials 0.000 claims description 18
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 18
- 239000011707 mineral Substances 0.000 claims description 18
- 229910052684 Cerium Inorganic materials 0.000 claims description 17
- 229910052782 aluminium Inorganic materials 0.000 claims description 16
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 15
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 claims description 14
- 239000011777 magnesium Substances 0.000 claims description 12
- -1 alkaline earth metal aluminates Chemical class 0.000 claims description 11
- 150000001875 compounds Chemical class 0.000 claims description 10
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 9
- 229910052749 magnesium Inorganic materials 0.000 claims description 7
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 3
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 2
- 239000002689 soil Substances 0.000 claims description 2
- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 claims 1
- 238000001354 calcination Methods 0.000 abstract description 15
- 239000002243 precursor Substances 0.000 description 32
- 239000002245 particle Substances 0.000 description 22
- 238000004020 luminiscence type Methods 0.000 description 15
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 13
- 125000001424 substituent group Chemical group 0.000 description 10
- 229910001593 boehmite Inorganic materials 0.000 description 8
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 8
- 239000000725 suspension Substances 0.000 description 8
- 229910052761 rare earth metal Inorganic materials 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 150000002910 rare earth metals Chemical class 0.000 description 6
- 238000011282 treatment Methods 0.000 description 6
- 238000005259 measurement Methods 0.000 description 5
- 229910052693 Europium Inorganic materials 0.000 description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 4
- 229910019142 PO4 Inorganic materials 0.000 description 4
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 235000021317 phosphate Nutrition 0.000 description 4
- 238000004626 scanning electron microscopy Methods 0.000 description 4
- 238000001694 spray drying Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 239000002019 doping agent Substances 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 3
- 229910052746 lanthanum Inorganic materials 0.000 description 3
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 3
- 150000002823 nitrates Chemical class 0.000 description 3
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 3
- 238000005424 photoluminescence Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000005507 spraying Methods 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910052688 Gadolinium Inorganic materials 0.000 description 2
- 229910020068 MgAl Inorganic materials 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000001246 colloidal dispersion Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 2
- 229910001938 gadolinium oxide Inorganic materials 0.000 description 2
- 229940075613 gadolinium oxide Drugs 0.000 description 2
- CMIHHWBVHJVIGI-UHFFFAOYSA-N gadolinium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[Gd+3].[Gd+3] CMIHHWBVHJVIGI-UHFFFAOYSA-N 0.000 description 2
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 2
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 2
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 2
- 229910052706 scandium Inorganic materials 0.000 description 2
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 2
- KLZUFWVZNOTSEM-UHFFFAOYSA-K Aluminum fluoride Inorganic materials F[Al](F)F KLZUFWVZNOTSEM-UHFFFAOYSA-K 0.000 description 1
- 229910015999 BaAl Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910052692 Dysprosium Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910052779 Neodymium Inorganic materials 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- JNDMLEXHDPKVFC-UHFFFAOYSA-N aluminum;oxygen(2-);yttrium(3+) Chemical compound [O-2].[O-2].[O-2].[Al+3].[Y+3] JNDMLEXHDPKVFC-UHFFFAOYSA-N 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 150000001642 boronic acid derivatives Chemical class 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 229910000420 cerium oxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 150000003841 chloride salts Chemical class 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 239000007771 core particle Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 238000001962 electrophoresis Methods 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 238000001033 granulometry Methods 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000002372 labelling Methods 0.000 description 1
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Inorganic materials [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 1
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical class [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000004627 transmission electron microscopy Methods 0.000 description 1
- LSGOVYNHVSXFFJ-UHFFFAOYSA-N vanadate(3-) Chemical class [O-][V]([O-])([O-])=O LSGOVYNHVSXFFJ-UHFFFAOYSA-N 0.000 description 1
- 229910019901 yttrium aluminum garnet Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
- 229910000166 zirconium phosphate Inorganic materials 0.000 description 1
- LEHFSLREWWMLPU-UHFFFAOYSA-B zirconium(4+);tetraphosphate Chemical compound [Zr+4].[Zr+4].[Zr+4].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LEHFSLREWWMLPU-UHFFFAOYSA-B 0.000 description 1
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
- C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
- C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
- C09K11/7774—Aluminates
-
- 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
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/628—Coating the powders or the macroscopic reinforcing agents
- C04B35/62897—Coatings characterised by their thickness
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
- C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/50—Wavelength conversion elements
Definitions
- the present invention relates to a composition based on an aluminate, heart / shell type, a phosphor derived from this composition and processes for their preparation.
- Cerium and terbium aluminates are well known for their luminescence properties. They emit a green light when they are irradiated by certain energetic radiations. Phosphors exploiting this property are commonly used on an industrial scale, for example in tristimulus fluorescent lamps or in plasma systems.
- the object of the invention is to provide phosphors having the properties of phosphors currently known but having a lower cost.
- the invention relates to a composition which is characterized in that it comprises:
- the invention also relates to a phosphor which has a core and a shell as described above and which is obtained from the composition of the invention.
- rare earth we mean for the rest of the description the elements of the group constituted by scandium, yttrium and the elements of the periodic classification of atomic number included between 57 and 71 inclusively.
- calcinations for a given temperature and duration correspond, unless otherwise indicated, to calcinations under air at a temperature level over the time indicated.
- specific surface is meant the specific surface B.E.T. determined by nitrogen adsorption according to ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the journal "The Journal of the American Chemical Society, 60, 309 (1938)".
- compositions comprising an aluminate, also called “compositions” or “precursors”, and phosphors obtained from these precursors.
- the luminophores themselves have sufficient luminescence properties to make them directly usable in the desired applications.
- the precursors have no luminescence properties or possibly luminescence properties generally too weak for use in these same applications.
- compositions comprising an aluminate or precursors
- compositions of the invention comprising an aluminate are characterized by their specific structure of the core / shell type which will be described below.
- the mineral core is based on a material that can be in particular an oxide or a phosphate.
- zirconium oxides mention may in particular be made of zirconium oxides
- Ziirconia zinc, titanium, magnesium, aluminum (alumina) and oxides of one or more rare earths, one of which can possibly play the role of dopant.
- the rare earth oxide gadolinium oxide, yttrium oxide and cerium oxide may be mentioned more particularly.
- Yttrium oxide, gadolinium oxide, zirconia, optionally doped with a rare earth, and alumina may be chosen preferably.
- Alumina may be chosen even more preferably because it has the particular advantage of allowing a calcination at a higher temperature during the passage of the precursor to the phosphor without there being a diffusion of the dopant in the heart. This thus makes it possible to obtain a product whose luminescence properties are optimal because of a better crystallization of the shell, a consequence of the higher calcination temperature.
- orthophosphates of one or more rare earths one of which may optionally act as a dopant, such as lanthanum (LaPO 4 ), lanthanum and cerium ((LaCe) PO 4 ), or yttrium ( YP0 4 ), gadolinium as well as polyphosphates of rare earths or aluminum.
- Alkaline earth phosphates can also be mentioned as
- mineral compounds such as vanadates, in particular rare earth (YVO 4 ), germanates, silicates, in particular zinc or zirconium silicate, tungstates, molybdates, sulphates (BaSO 4) are suitable.
- rare earth aluminates such as yttrium aluminate Y3Al5O12, optionally doped with cerium
- perovskites such as YAIO3 or LaAIO3 these perovskites may be optionally doped with cerium or else alkaline earth metal aluminates, optionally doped with a rare earth other than terbium or europium, such as barium and / or magnesium aluminates, such as MgAl 2 O 4, BaAl 2 O 4, BaMgA 0 Oi 7, or LnMgAI-nO-19, Ln denoting at least one rare earth metal other than terbium or europium.
- Magnesium aluminates may be preferred.
- mixed oxides in particular rare earth oxides, for example mixed oxides of zirconium and cerium, mixed phosphates, in particular rare earths, and phosphovanadates, may be suitable.
- the mineral core is based on is meant a set comprising at least 50%, preferably at least 70%, and more preferably at least 80% or 90% by weight of the material in question.
- the heart can be essentially constituted by said material (namely at a content of at least 95% by weight, for example at least 98%, or even at least 99% by weight) or entirely constituted by this material.
- the core may have a mean diameter of in particular between 1 and 10 ⁇ m, preferably between 2.5 ⁇ m and 7 ⁇ m.
- These diameter values can be determined by scanning electron microscopy (SEM) by random counting of at least 150 particles.
- the dimensions of the core, as well as those of the shell which will be described later, can also be measured in particular in transmission electron microscopy photographs of sections of the compositions / precursors of the invention.
- compositions / precursors of the invention is the shell.
- This shell homogeneously covers the heart to a given thickness which is equal to or greater than 300 nm.
- homogeneous is meant a continuous layer, completely covering the core and whose thickness is preferably never less than the given value of 300 nm. This homogeneity is notably visible on SEM images.
- X-ray diffraction (XRD) measurements also reveal the presence of two distinct compositions between the core and the shell.
- the thickness of the shell may be more particularly at least 500 nm. It may be equal to or less than 2000 nm (2 pm), more particularly between 750 nm and 1500 nm.
- the shell is based on an aluminate of formula (1).
- the aluminate of formula (1) can also, in a known manner, contain additional elements, called "substituents" because these elements are considered to be in partial substitution of elements Ce, Tb, Mg and Al. in particular to modify the luminescence properties of the phosphors derived from the compounds of the invention.
- Ce and / or Tb may be partially substituted by at least one rare earth which may especially be gadolinium, europium or neodymium. lanthanum and dysprosium, these elements can be taken alone or in combination.
- Magnesium may also be partially substituted by at least one element selected from calcium, zinc, manganese or cobalt.
- the aluminum may also be partially substituted by at least one element selected from gallium, scandium, boron, germanium, phosphorus or silicon.
- substitutions make it possible to modify the luminescence properties of the phosphors resulting from the compositions of the invention.
- the amounts of these substituents can vary, in a known manner, in wide ranges, the minimum amount of substituent is that below which the substituent no longer produces effect and it is generally and in a known manner at least a few ppm and it can go up to several percent.
- the amount of magnesium substituent is at most 30%, more particularly at most 20% and even more particularly at most 10%, this amount being expressed as atomic% (atomic ratio substituent / (substituent For aluminum, this quantity, expressed in the same way, is generally not more than 15%, the minimum amount of substituent can be at least 0.1%, for example, for cerium and / or or terbium this quantity, always expressed in the same way, is generally at most 5%.
- cerium, terbium and their relative proportion can vary within very wide limits.
- the minimum content of cerium or terbium is that below which the product would no longer exhibit luminescence property. More particularly, however, and with reference to formula (1) the value of a may be between 0.5 and 0.8 and that of b between 0.2 and 0.5.
- compositions / precursors of the invention consist of particles which have a mean diameter which is preferably between 1.5 ⁇ m and 15 ⁇ m. This diameter may more particularly be between 3 ⁇ m and 10 ⁇ m and even more particularly between 4 ⁇ m and 8 ⁇ m.
- the average diameter referred to is the volume average of the diameters of a particle population.
- the particle size values given here and for the rest of the description are measured by the laser granulometry technique, for example by means of a Malvern laser particle size analyzer, on a sample of particles dispersed in ultrasonic water (130 W) for 1 minute 30 seconds.
- the particles preferably have a low dispersion index, typically at most 0.7, more particularly at most 0.6 and even more particularly at most 0.5.
- D 84 is the particle diameter for which 84% of the particles have a diameter less than D 84 ;
- D-16 is the particle diameter for which 16% of the particles have a diameter less than Di 6 ;
- D 50 is the average diameter of the particles, diameter for which 50% of the particles have a diameter less than D 50 .
- compositions or precursors according to the invention may optionally have luminescence properties at variable wavelengths depending on the composition of the product and after exposure to a given wavelength radius, it is possible and even necessary to further improve these luminescence properties by proceeding with the products to post-treatments, and this in order to obtain a real luminophore directly usable as such in the desired application.
- compositions according to the invention which have not been subjected to heat treatments greater than approximately 950 ° C., since such products generally have luminescence properties which can be judged as not satisfying the minimum brightness criterion of commercial phosphors which can be used directly and as such, without any subsequent transformation.
- compositions which, possibly after having been subjected to appropriate treatments, develop suitable and sufficient glosses for use directly by an applicator, for example in trichromatic lamps, may be qualified as luminophores.
- the description of the phosphors according to the invention will be made below.
- the phosphors of the invention have the same structure as the compositions or precursors described above. They therefore comprise a mineral core, a shell based on the aluminate of formula (1) and having a thickness of at least 300 nm.
- the particles of the phosphors may thus have an average diameter of between 1.5 m and 15 m.
- the process for preparing the compositions / precursors is characterized in that it comprises the following steps:
- a liquid mixture comprising compounds of aluminum and the other elements cerium, terbium and Mg and the mineral core;
- the dried product is calcined at a temperature of between 700 ° C. and 950 ° C.
- this process comprises a first step in which a liquid mixture is formed which is a solution or a suspension or a gel, compounds of aluminum and other elements cerium, terbium and Mg, this mixture comprising in part besides the mineral heart.
- This mixture may also include the substituent elements which have been mentioned above.
- inorganic salts or hydroxides are usually used.
- salts mention may be made of nitrates preferably, in particular for aluminum, europium and magnesium.
- aluminum compound a sol or colloidal dispersion of aluminum.
- colloidal dispersion of aluminum may have particles or colloids whose size is between 1 nm and 300 nm. Aluminum can be present in the soil as boehmite.
- the next step is to dry the previously prepared mixture. This drying is done by atomization.
- Spray drying is understood to mean spray drying of the mixture in a hot atmosphere (spray-drying).
- the atomization can be carried out using any sprayer known per se, for example by a spraying nozzle of the watering apple or other type. It is also possible to use so-called turbine atomizers.
- spraying techniques that may be used in the present process, reference may be made in particular to Handbook of Industrial Drying, Chapter 10 Industrial spray-drying Systems, Arun S ,. Numjumbar 2007.
- the last step of the process consists of calcining the product obtained after drying.
- the calcination is carried out at a temperature of between 700 ° C. and 950 ° C., more particularly between 700 ° C. and 900 ° C.
- Calcination is usually done under air.
- the precursor compound of the invention is obtained at the end of this calcination.
- the luminophores of the invention are obtained by calcination at a temperature of at least 1200 ° C. of the compositions or precursors as described above or of the compositions or precursors obtained by the process which has also been described above. It will be noted that this is a lower temperature than that required for the preparation of a phosphor by firing. This temperature may be more particularly at least 1400 ° C. By this treatment, the compositions or precursors are converted into effective phosphors.
- the precursors themselves may have intrinsic luminescence properties, these properties are generally insufficient for the intended applications and are greatly improved by the calcination treatment.
- the calcination can be carried out under air, under an inert gas but also and preferably under a reducing atmosphere (H 2 , N 2 / H 2 or Ar / H 2 for example) in order to in the latter case, to convert all the species Ce and Tb to their oxidation state (+111).
- a reducing atmosphere H 2 , N 2 / H 2 or Ar / H 2 for example
- the calcination can be carried out in the presence of a flux or fluxing agent of the fluoride type, such as, for example, lithium, aluminum or magnesium fluoride.
- a flux or fluxing agent of the fluoride type such as, for example, lithium, aluminum or magnesium fluoride.
- the particles are advantageously washed, so as to obtain the purest phosphor possible and in a deagglomerated or weakly agglomerated state.
- the aforementioned heat treatments make it possible to obtain luminophores which retain a core / shell structure and a particle size distribution close to those of the precursor particles.
- the heat treatment can be conducted without inducing sensitive phenomena of diffusion of the species Ce and Tb from the outer layer of the phosphor to the core.
- the heat treatment described for the preparation of the precursor and the calcination for the conversion of the precursor into a phosphor it is possible to conduct in a single step the heat treatment described for the preparation of the precursor and the calcination for the conversion of the precursor into a phosphor.
- the phosphor is obtained directly without stopping at the precursor.
- the phosphors of the invention can be used as green lumlinophores and can thus be used in the manufacture of any apparatus incorporating phosphors such as trichromatic lamps, light-emitting diodes and plasma screens.
- UV excitation labeling systems They can also be used in UV excitation labeling systems.
- organic matrices for example, plastic matrices or transparent polymers under UV .
- mineral for example silica
- organo-mineral hybrids for example, silica
- the invention accordingly relates to a device of the trichromatic lamp type, light emitting diode or plasma screen comprising the phosphor of the invention or a device of the same type which is manufactured using the phosphor of the invention.
- the use of this phosphor in the manufacture of the devices described above is done according to well-known techniques, for example by screen printing, by spraying, by electrophoresis, by sedimentation or by soaking (deep coating).
- Alumina of the alpha alumina type, of spherical morphology, D 50 3 ⁇ m (laser particle size), BET surface area ⁇ 1 m 2 / g
- the photoluminescence (PL) efficiency measurements of phosphors are made by integration of the emission spectrum between 450 nm and 700 nm, under excitation at 254 nm, using a Jobin - Yvon spectrophotometer.
- the photoluminescence yield of Example 1 is taken as a reference with a value of 100.
- the transmission electron micrographs are made on a section (microtomy) of the particles, using a SEM microscope.
- the spatial resolution of the apparatus for chemical composition measurements by EDS (energy dispersive spectroscopy) is ⁇ 2 nm.
- the correlation of observed morphologies and measured chemical compositions makes it possible to highlight the core-shell structure and to measure the thickness of the shell on the plates.
- the measurements of chemical composition can also be carried out by EDS on plates made by STEM HAADF.
- the measurement corresponds to an average performed on at least two spectra.
- This example relates to a product according to the prior art of formula (It 0 67Tbo, 33) MgAl 11 0 19.
- boehmite 100 g are mixed with 1 L of water with stirring. The pH of the suspension is then 5. 19.08 g of 5 mol / l HNO 3 are added to bring the pH down to 2, the suspension is allowed to stand overnight and a stable boehmite sol is obtained. 52.3 g and 28.8 g of solutions of nitrates of cerium and terbium and 33.6 g of magnesium nitrate are respectively mixed.
- the resulting mixture is added to the boehmite sol and water is added so that the solids content of the suspension is less than 7%.
- This example relates to a core / shell type product according to the invention and whose core is alumina and whose shell corresponds to the formula (Ce 0 , 67Tbo, 33) MgAI 11 0 19 .
- boehmite 49.4 g are mixed with 0.3L of water with stirring. The pH of the suspension is then 5. 9.3 g of 5 mol / l HNO 3 are added to bring the pH down to 2, the suspension is allowed to stand overnight and a stable boehmite sol is obtained.
- the resulting mixture is added to the boehmite sol. 0.8 l of water and then 4.4 g of alumina are also added as the core, so that the core / shell molar ratio is 40% of the core and 60% of the shell.
- the product obtained is then washed with 300 ml of hot water at 80 ° C. for 3 hours, filtered and dried in an oven.
- the characteristics of the products obtained in the preceding examples are given in the table below.
- R denotes the mass ratio of terbium relative to the phosphor expressed in g of Tb 4 O 7 relative to the mass of the phosphor in kg.
- the precursor and phosphor of Example 2 also show by observation in SEM on a product section a typical morphology heart-shell type.
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Abstract
The composition of the invention includes: an inorganic core and an aluminate shell, said aluminate being of the formula (CeaTbb)Mg1+xAl11+yO19+x+y (1), where a, b, x and y comply with the relations a+b=1-0.2 ≤ x ≤ +0.2 and -0.2 ≤ y ≤ +0.2, wherein the shell uniformly covers the inorganic core over a thickness of no less than 300 nm. The phosphor of the invention is obtained by calcinating the composition of the invention at a temperature of at least 1200°C.
Description
COMPOSITION A BASE D'UN ALUMINATE, DE TYPE COMPOSITION BASED ON ALUMINATE, TYPE
CŒUR/COQUILLE, LUMINOPHORE ISSU DE CETTE COMPOSITION ET HEART / SHELL, LUMINOPHORE FROM THIS COMPOSITION AND
PROCEDES DE PREPARATION METHODS OF PREPARATION
La présente invention concerne une composition à base d'un aluminate, de type cœur/coquille, un luminophore issu de cette composition et leurs procédés de préparation. The present invention relates to a composition based on an aluminate, heart / shell type, a phosphor derived from this composition and processes for their preparation.
Les aluminates à base de cérium et de terbium sont bien connus pour leurs propriétés de luminescence. Ils émettent une lumière verte lorsqu'ils sont irradiés par certains rayonnements énergétiques. Des luminophores exploitant cette propriété sont couramment utilisés à l'échelle industrielle, par exemple dans des lampes fluorescentes trichromatiques ou dans des systèmes plasma. Cerium and terbium aluminates are well known for their luminescence properties. They emit a green light when they are irradiated by certain energetic radiations. Phosphors exploiting this property are commonly used on an industrial scale, for example in tristimulus fluorescent lamps or in plasma systems.
Ces luminophores contiennent des terres rares dont le prix est élevé et qui est aussi soumis à des fluctuations importantes. La réduction du coût de ces luminophores constitue donc un enjeu important. These phosphors contain rare earths that are expensive and also subject to significant fluctuations. Reducing the cost of these luminophores is therefore an important issue.
De plus la rareté de certaines terres rares comme le terbium conduit à chercher à en réduire la quantité dans les luminophores. Moreover the rarity of some rare earths such as terbium leads to seek to reduce the amount in the phosphors.
L'objet de l'invention est de fournir des luminophores présentant les propriétés des luminophores actuellement connus mais ayant un coût plus faible. The object of the invention is to provide phosphors having the properties of phosphors currently known but having a lower cost.
Dans ce but, l'invention concerne une composition qui est caractérisée en ce qu'elle comprend : For this purpose, the invention relates to a composition which is characterized in that it comprises:
- un cœur minéral; - a mineral heart;
- une coquille à base d'un aluminate de formule : a shell based on an aluminate of formula:
(CeaTbb)Mg1 +xAI1 1 +yOi 9+x+y (1 ) (This at Tbb) Mg 1 + xAI 1 1 + yOi 9 + x + y (1)
dans laquelle a, b, x et y vérifient les relations : where a, b, x, and y satisfy the relationships:
a+b=1 a + b = 1
-0,2 < x < +0,2 -0.2 <x <+0.2
-0,2 < y < +0,2 -0.2 <y <+0.2
et recouvrant de façon homogène le cœur minéral sur une épaisseur égale ou supérieure à 300 nm. and homogeneously overlying the mineral core to a thickness equal to or greater than 300 nm.
L'invention concerne aussi un luminophore qui présente un cœur et une coquille comme décrit ci-dessus et qui est obtenu à partir de la composition de l'invention. The invention also relates to a phosphor which has a core and a shell as described above and which is obtained from the composition of the invention.
D'autres caractéristiques, détails et avantages de l'invention apparaîtront encore plus complètement à la lecture de la description qui va suivre, ainsi que des divers exemples concrets mais non limitatifs destinés à l'illustrer.
On précise aussi pour la suite de la description que, sauf indication contraire, dans toutes les gammes ou limites de valeurs qui sont données, les valeurs aux bornes sont incluses, les gammes ou limites de valeurs ainsi définies couvrant donc toute valeur au moins égale et supérieure à la borne inférieure et/ou au plus égale ou inférieure à la borne supérieure. Other features, details and advantages of the invention will appear even more fully on reading the description which follows, as well as various concrete but non-limiting examples intended to illustrate it. It is also specified for the remainder of the description that, unless otherwise indicated, in all ranges or limits of values that are given, the values at the terminals are included, the ranges or limits of values thus defined thus covering any value at least equal to and greater than the lower bound and / or at most equal to or less than the upper bound.
Par terre rare on entend pour la suite de la description les éléments du groupe constitué par le scandium, l'yttrium et les éléments de la classification périodique de numéro atomique compris inclusivement entre 57 et 71 . For rare earth we mean for the rest of the description the elements of the group constituted by scandium, yttrium and the elements of the periodic classification of atomic number included between 57 and 71 inclusively.
En outre, les calcinations pour une température et une durée données correspondent, sauf indication contraire, à des calcinations sous air à un palier de température sur la durée indiquée. In addition, the calcinations for a given temperature and duration correspond, unless otherwise indicated, to calcinations under air at a temperature level over the time indicated.
On entend par surface spécifique, la surface spécifique B.E.T. déterminée par adsorption d'azote conformément à la norme ASTM D 3663-78 établie à partir de la méthode BRUNAUER - EMMETT- TELLER décrite dans le périodique "The Journal of the American Chemical Society, 60, 309 (1938)". By specific surface is meant the specific surface B.E.T. determined by nitrogen adsorption according to ASTM D 3663-78 established from the BRUNAUER-EMMETT-TELLER method described in the journal "The Journal of the American Chemical Society, 60, 309 (1938)".
Comme cela a été vu plus haut, l'invention concerne deux types de produits : des compositions comprenant un aluminate, appelées aussi par la suite « compositions » ou « précurseurs », et des luminophores obtenus à partir de ces précurseurs. Les luminophores ont, eux, des propriétés de luminescence suffisantes pour les rendre directement utilisables dans les applications souhaitées. Les précurseurs n'ont pas de propriétés de luminescence ou éventuellement des propriétés de luminescence généralement trop faibles pour une utilisation dans ces mêmes applications. As has been seen above, the invention relates to two types of products: compositions comprising an aluminate, also called "compositions" or "precursors", and phosphors obtained from these precursors. The luminophores themselves have sufficient luminescence properties to make them directly usable in the desired applications. The precursors have no luminescence properties or possibly luminescence properties generally too weak for use in these same applications.
Ces deux types de produits vont maintenant être décrits plus précisément. These two types of products will now be described more precisely.
Les compositions comprenant un aluminate ou précurseurs Compositions comprising an aluminate or precursors
Les compositions de l'invention comprenant un aluminate se caractérisent par leur structure spécifique de type cœur/coquille qui va être décrite ci-dessous. The compositions of the invention comprising an aluminate are characterized by their specific structure of the core / shell type which will be described below.
Le cœur minéral est à base d'un matériau qui peut être notamment un oxyde ou un phosphate. The mineral core is based on a material that can be in particular an oxide or a phosphate.
Parmi les oxydes, on peut citer en particulier les oxydes de zirconium Among the oxides, mention may in particular be made of zirconium oxides
(zircone), de zinc, de titane, de magnésium, d'aluminium (alumine) et les oxydes d'une ou plusieurs terres rares dont une peut éventuellement jouer le rôle de dopant. Comme oxyde de terre rare on peut mentionner plus particulièrement encore l'oxyde de gadolinium, l'oxyde d'yttrium et l'oxyde de cérium.
L'oxyde d'yttrium, l'oxyde de gadolinium, la zircone, éventuellement dopée par une terre rare, et l'alumine pourront être choisis de préférence. L'alumine peut être choisie encore plus préférentiellement car elle présente notamment l'avantage de permettre une calcination à température plus élevée lors du passage du précurseur au luminophore sans que l'on observe une diffusion du dopant dans le cœur. Ceci permet ainsi d'obtenir un produit dont les propriétés de luminescence sont optimales du fait d'une meilleure cristallisation de la coquille, conséquence de la température plus élevée de calcination. (Zirconia), zinc, titanium, magnesium, aluminum (alumina) and oxides of one or more rare earths, one of which can possibly play the role of dopant. As the rare earth oxide, gadolinium oxide, yttrium oxide and cerium oxide may be mentioned more particularly. Yttrium oxide, gadolinium oxide, zirconia, optionally doped with a rare earth, and alumina may be chosen preferably. Alumina may be chosen even more preferably because it has the particular advantage of allowing a calcination at a higher temperature during the passage of the precursor to the phosphor without there being a diffusion of the dopant in the heart. This thus makes it possible to obtain a product whose luminescence properties are optimal because of a better crystallization of the shell, a consequence of the higher calcination temperature.
Parmi les phosphates, on peut mentionner les orthophosphates d'une ou plusieurs terres rares dont une peut éventuellement jouer le rôle de dopant, telles que le lanthane (LaP04), le lanthane et le cérium ((LaCe)P04), ryttrium (YP04), le gadolinium ainsi que les polyphosphates de terres rares ou d'aluminium. Among the phosphates, mention may be made of orthophosphates of one or more rare earths, one of which may optionally act as a dopant, such as lanthanum (LaPO 4 ), lanthanum and cerium ((LaCe) PO 4 ), or yttrium ( YP0 4 ), gadolinium as well as polyphosphates of rare earths or aluminum.
On peut aussi mentionner les phosphates alcalino-terreux comme Alkaline earth phosphates can also be mentioned as
Ca2P2O7, le phosphate de zirconium ZrP2O7, les hydroxyapatites d'alcalino- terreux. Ca 2 P2O7, zirconium phosphate ZrP 2 O 7 , alkaline earth hydroxyapatites.
Par ailleurs, conviennent d'autres composés minéraux tels que les vanadates, notamment de terre rare, (YVO4), les germanates, les silicates, notamment le silicate de zinc ou de zirconium, les tungstates, les molybdates, les sulfates (BaSO4), les borates (YBO3, GdBOs), les carbonates et les titanates (tel que BaTiOs), les zirconates, les aluminates de terre rare comme l'aluminate d'yttrium Y3AI5O12, éventuellement dopée par du cérium, les pérovskites comme YAIO3 ou LaAIO3, ces pérovskites pouvant être dopées par du cérium éventuellement ou encore les aluminates de métaux alcalino- terreux, éventuellement dopés par une terre rare autre que le terbium ou l'europium, comme les aluminates de baryum et/ou de magnésium, tels que MgAI2O4, BaAI2O4, BaMgA 0Oi7, ou encore LnMgAI-nO-19, Ln désignant au moins une terre rare autre que le terbium ou l'europium. Furthermore, other mineral compounds such as vanadates, in particular rare earth (YVO 4 ), germanates, silicates, in particular zinc or zirconium silicate, tungstates, molybdates, sulphates (BaSO 4) are suitable. ), borates (YBO3, GdBOs), carbonates and titanates (such as BaTiOs), zirconates, rare earth aluminates such as yttrium aluminate Y3Al5O12, optionally doped with cerium, perovskites such as YAIO3 or LaAIO3 these perovskites may be optionally doped with cerium or else alkaline earth metal aluminates, optionally doped with a rare earth other than terbium or europium, such as barium and / or magnesium aluminates, such as MgAl 2 O 4, BaAl 2 O 4, BaMgA 0 Oi 7, or LnMgAI-nO-19, Ln denoting at least one rare earth metal other than terbium or europium.
Les aluminates de magnésium peuvent être préférés. Magnesium aluminates may be preferred.
Enfin, peuvent être appropriés les composés issus des composés précédents tels que les oxydes mixtes, notamment de terres rares, par exemple les oxydes mixtes de zirconium et de cérium, les phosphates mixtes, notamment de terres rares, et les phosphovanadates. Finally, compounds derived from the above compounds, such as mixed oxides, in particular rare earth oxides, for example mixed oxides of zirconium and cerium, mixed phosphates, in particular rare earths, and phosphovanadates, may be suitable.
Par l'expression "le cœur minéral est à base de", on entend désigner un ensemble comprenant au moins 50%, de préférence au moins 70%, et plus préférentiellement au moins 80%, voire 90% en masse du matériau considéré. Selon un mode de réalisation particulier, le cœur peut être essentiellement
constitué par ledit matériau (à savoir en une teneur d'au moins 95% en masse, par exemple au moins 98%, voire au moins 99% en masse) ou encore entièrement constitué par ce matériau. By the expression "the mineral core is based on" is meant a set comprising at least 50%, preferably at least 70%, and more preferably at least 80% or 90% by weight of the material in question. According to a particular embodiment, the heart can be essentially constituted by said material (namely at a content of at least 95% by weight, for example at least 98%, or even at least 99% by weight) or entirely constituted by this material.
Le cœur peut avoir un diamètre moyen compris notamment entre 1 et 10 pm, de préférence compris entre 2,5 pm et 7 pm. The core may have a mean diameter of in particular between 1 and 10 μm, preferably between 2.5 μm and 7 μm.
Ces valeurs de diamètre peuvent être déterminées par microscopie électronique à balayage (MEB) par comptage statistique d'au moins 150 particules. These diameter values can be determined by scanning electron microscopy (SEM) by random counting of at least 150 particles.
Les dimensions du cœur, de même que celles de la coquille qui sera décrite plus loin, peuvent aussi être mesurées notamment sur des photographies de microscopie électronique en transmission de coupes des compositions/précurseurs de l'invention. The dimensions of the core, as well as those of the shell which will be described later, can also be measured in particular in transmission electron microscopy photographs of sections of the compositions / precursors of the invention.
L'autre caractéristique de structure des compositions/précurseurs de l'invention est la coquille. The other structure characteristic of the compositions / precursors of the invention is the shell.
Cette coquille recouvre de façon homogène le cœur sur une épaisseur donnée qui est égale ou supérieure à 300 nm. Par "homogène", on entend une couche continue, recouvrant totalement le cœur et dont l'épaisseur n'est de préférence jamais inférieure à la valeur donnée de 300 nm. Cette homogénéité est notamment visible sur des clichés de MEB. Des mesures de diffraction par des rayons X (DRX) mettent en évidence en outre la présence de deux compositions distinctes entre le cœur et la coquille. This shell homogeneously covers the heart to a given thickness which is equal to or greater than 300 nm. By "homogeneous" is meant a continuous layer, completely covering the core and whose thickness is preferably never less than the given value of 300 nm. This homogeneity is notably visible on SEM images. X-ray diffraction (XRD) measurements also reveal the presence of two distinct compositions between the core and the shell.
L'épaisseur de la coquille peut être plus particulièrement d'au moins 500 nm. Elle peut être égale ou inférieure à 2000 nm (2pm), plus particulièrement comprise entre 750 nm et 1500 nm. The thickness of the shell may be more particularly at least 500 nm. It may be equal to or less than 2000 nm (2 pm), more particularly between 750 nm and 1500 nm.
La coquille est à base d'un aluminate de formule (1 ). The shell is based on an aluminate of formula (1).
L'aluminate de formule (1 ) peut en outre, d'une manière connue, contenir des éléments additionnels, appelés « substituants » car ces éléments sont considérés comme venant en substitution partielle des éléments Ce, Tb, Mg et Al. Ces substitutions permettent notamment de modifier les propriétés de luminescence des luminophores issus des composés de l'invention. The aluminate of formula (1) can also, in a known manner, contain additional elements, called "substituents" because these elements are considered to be in partial substitution of elements Ce, Tb, Mg and Al. in particular to modify the luminescence properties of the phosphors derived from the compounds of the invention.
On va donner ci-dessous des exemples de ces substituant pour chaque élément constitutif sur la base de ce qui est communément admis actuellement dans l'état de la technique. Ceci implique que l'on ne sortirait pas de la présente invention si un substituant décrit pour un élément constitutif donné s'avérait être en fait par la suite en substitution d'un autre élément constitutif que celui présumé dans la présente description. Examples of these substituents for each constituent element will be given below based on what is currently commonly accepted in the state of the art. This implies that it would not depart from the present invention if a substitute described for a given constituent element would in fact be in fact substituted for another constituent element than that presumed in the present description.
Ainsi, Ce et/ou Tb peuvent être partiellement substitués, par au moins une terre rare qui peut être notamment le gadolinium, l'europium, le néodyme,
le lanthane et le dysprosium, ces éléments pouvant être pris seul ou en combinaison. Thus, Ce and / or Tb may be partially substituted by at least one rare earth which may especially be gadolinium, europium or neodymium. lanthanum and dysprosium, these elements can be taken alone or in combination.
Le magnésium peut aussi être partiellement substitué par au moins un élément choisi parmi le calcium, le zinc, le manganèse ou le cobalt. Magnesium may also be partially substituted by at least one element selected from calcium, zinc, manganese or cobalt.
Enfin, l'aluminium peut aussi être partiellement substitué par au moins un élément choisi parmi le gallium, le scandium, le bore, le germanium, le phosphore ou le silicium. Finally, the aluminum may also be partially substituted by at least one element selected from gallium, scandium, boron, germanium, phosphorus or silicon.
Les substitutions permettent de modifier les propriétés de luminescence des luminophores issus des compositions de l'invention. The substitutions make it possible to modify the luminescence properties of the phosphors resulting from the compositions of the invention.
Les quantités de ces substituant peuvent varier, d'une manière connue, dans de larges gammes, la quantité minimale de substituant est celle en deçà de laquelle le substituant ne produit plus d'effet et elle est généralement et de manière connue d'au moins quelques ppm et elle peut aller jusqu'à plusieurs pour-cent. The amounts of these substituents can vary, in a known manner, in wide ranges, the minimum amount of substituent is that below which the substituent no longer produces effect and it is generally and in a known manner at least a few ppm and it can go up to several percent.
Généralement toutefois, la quantité de substituant du magnésium est d'au plus 30%, plus particulièrement d'au plus 20% et encore plus particulièrement d'au plus 10%, cette quantité étant exprimée en % atomique (rapport atomique substituant/(substituant + Mg). Pour l'aluminium, cette quantité, exprimée de la même manière, est généralement d'au plus 15%. La quantité minimale de substituant peut être d'au moins 0, 1 % par exemple. Pour le cérium et/ou le terbium cette quantité, toujours exprimée de la même manière, est généralement d'au plus 5%. Generally, however, the amount of magnesium substituent is at most 30%, more particularly at most 20% and even more particularly at most 10%, this amount being expressed as atomic% (atomic ratio substituent / (substituent For aluminum, this quantity, expressed in the same way, is generally not more than 15%, the minimum amount of substituent can be at least 0.1%, for example, for cerium and / or or terbium this quantity, always expressed in the same way, is generally at most 5%.
Les proportions en cérium, en terbium et leur proportion relative peuvent varier dans de très larges limites. La teneur minimale en cérium ou terbium est celle en deçà de laquelle le produit ne présenterait plus de propriété de luminescence. Plus particulièrement toutefois et en référence à la formule (1 ) la valeur de a peut être comprise entre 0,5 et 0,8 et celle de b entre 0,2 et 0,5. The proportions of cerium, terbium and their relative proportion can vary within very wide limits. The minimum content of cerium or terbium is that below which the product would no longer exhibit luminescence property. More particularly, however, and with reference to formula (1) the value of a may be between 0.5 and 0.8 and that of b between 0.2 and 0.5.
L'invention s'applique particulièrement aux aluminates de formule (1 ) dans laquelle x = y = 0. The invention is particularly applicable to aluminates of formula (1) in which x = y = 0.
Les compositions/précurseurs de l'invention sont constitués de particules qui présentent un diamètre moyen qui est de préférence compris entre 1 ,5 pm et 15 pm. Ce diamètre peut être plus particulièrement compris entre 3 pm et 10 pm et encore plus particulièrement entre 4 m et 8 pm. The compositions / precursors of the invention consist of particles which have a mean diameter which is preferably between 1.5 μm and 15 μm. This diameter may more particularly be between 3 μm and 10 μm and even more particularly between 4 μm and 8 μm.
Le diamètre moyen auquel il est fait référence est la moyenne en volume des diamètres d'une population de particules. The average diameter referred to is the volume average of the diameters of a particle population.
Les valeurs de granulométrie données ici et pour le reste de la description sont mesurées par la technique de granulométrie laser, par exemple au moyen d'un granulométre laser de type Malvern, sur un
échantillon de particules dispersées dans l'eau aux ultrasons (130 W) pendant 1 minute 30 secondes. The particle size values given here and for the rest of the description are measured by the laser granulometry technique, for example by means of a Malvern laser particle size analyzer, on a sample of particles dispersed in ultrasonic water (130 W) for 1 minute 30 seconds.
Par ailleurs, les particules ont de préférence un faible indice de dispersion, typiquement d'au plus 0,7, plus particulièrement d'au plus 0,6 et encore plus particulièrement d'au plus 0,5. Moreover, the particles preferably have a low dispersion index, typically at most 0.7, more particularly at most 0.6 and even more particularly at most 0.5.
Par "indice de dispersion" d'une population de particules, on entend, au sens de la présente description, le rapport I tel que défini dans la formule (2) ci-dessous : By "dispersion index" of a population of particles is meant, in the sense of the present description, the ratio I as defined in formula (2) below:
I=(DB4- D16)/(2X D50) (2), I = (DB4-D 16 ) / (2X D 50 ) (2),
où : D84 est le diamètre des particules pour lequel 84% des particules ont un diamètre inférieur à D84; where: D 84 is the particle diameter for which 84% of the particles have a diameter less than D 84 ;
D-I6 est le diamètre des particules pour lequel 16% des particules ont un diamètre inférieur à Di6; et D-16 is the particle diameter for which 16% of the particles have a diameter less than Di 6 ; and
D50 est le diamètre moyen des particules, diamètre pour lequel 50% des particules ont un diamètre inférieur à D50. D 50 is the average diameter of the particles, diameter for which 50% of the particles have a diameter less than D 50 .
Bien que les compositions ou précurseurs selon l'invention puissent éventuellement présenter des propriétés de luminescence à des longueurs d'onde variables en fonction de la composition du produit et après exposition à un rayon de longueur d'onde donné, il est possible et même nécessaire d'améliorer encore ces propriétés de luminescence en procédant sur les produits à des post-traitements, et ceci afin d'obtenir un véritable luminophore directement utilisable en tant que tel dans l'application souhaitée. Although the compositions or precursors according to the invention may optionally have luminescence properties at variable wavelengths depending on the composition of the product and after exposure to a given wavelength radius, it is possible and even necessary to further improve these luminescence properties by proceeding with the products to post-treatments, and this in order to obtain a real luminophore directly usable as such in the desired application.
On comprend que la frontière entre un simple précurseur et un réel luminophore reste arbitraire, et dépend du seul seuil de luminescence à partir duquel on considère qu'un produit peut être directement mis en œuvre de manière acceptable par un utilisateur. It is understood that the boundary between a simple precursor and a real phosphor remains arbitrary, and depends on the only luminescence threshold from which it is considered that a product can be directly implemented in a manner acceptable to a user.
Dans le cas présent, et de manière assez générale, on peut considérer et identifier comme précurseurs de luminophores des compositions selon l'invention qui n'ont pas été soumises à des traitements thermiques supérieurs à environ 950°C, car de tels produits présentent généralement des propriétés de luminescence que l'on peut juger comme ne satisfaisant pas au critère minimum de brillance des luminophores commerciaux susceptibles d'être utilisés directement et tels quels, sans aucune transformation ultérieure. A l'inverse, on peut qualifier de luminophores, les compositions qui, éventuellement après avoir été soumises à des traitements appropriés, développent des brillances convenables et suffisantes pour être utilisés directement par un applicateur, par exemple dans des lampes trichromatiques.
La description des luminophores selon l'invention va être faite ci- dessous. In the present case, and in a fairly general manner, it is possible to consider and identify as phosphor precursors compositions according to the invention which have not been subjected to heat treatments greater than approximately 950 ° C., since such products generally have luminescence properties which can be judged as not satisfying the minimum brightness criterion of commercial phosphors which can be used directly and as such, without any subsequent transformation. Conversely, compositions which, possibly after having been subjected to appropriate treatments, develop suitable and sufficient glosses for use directly by an applicator, for example in trichromatic lamps, may be qualified as luminophores. The description of the phosphors according to the invention will be made below.
Les luminophores The luminophores
Les luminophores de l'invention présentent la même structure que les compositions ou précurseurs décrits plus haut. Ils comprennent donc un cœur minéral, une coquille à base de l'aluminate de formule (1 ) et d'épaisseur d'au moins 300 nm. The phosphors of the invention have the same structure as the compositions or precursors described above. They therefore comprise a mineral core, a shell based on the aluminate of formula (1) and having a thickness of at least 300 nm.
Ainsi tout ce qui a été décrit précédemment au sujet de ces précurseurs s'applique de même ici pour la description des luminophores selon l'invention, notamment ce qui concerne les caractéristiques sur la structure constituée par le cœur minéral et la coquille homogène, sur la nature du cœur minéral, sur l'épaisseur de la coquille, qui là aussi, peut être égale ou supérieure à 300 nm, ainsi que les caractéristiques de granulométrie, les particules des luminophores pouvant ainsi présenter un diamètre moyen compris entre 1 ,5 m et 15 m. Thus, all that has been previously described with regard to these precursors is likewise applicable here for the description of the phosphors according to the invention, particularly as regards the characteristics on the structure constituted by the mineral core and the homogeneous shell, on the nature of the mineral core, on the thickness of the shell, which again may be equal to or greater than 300 nm, as well as particle size characteristics, the particles of the phosphors may thus have an average diameter of between 1.5 m and 15 m.
Les procédés de préparation des précurseurs et des luminophores de l'invention vont maintenant être décrits. The processes for preparing precursors and phosphors of the invention will now be described.
Le procédé de préparation des compositions ou précurseurs The process for preparing the compositions or precursors
Le procédé de préparation des compositions/précurseurs est caractérisé en ce qu'il comprend les étapes suivantes : The process for preparing the compositions / precursors is characterized in that it comprises the following steps:
- on forme un mélange liquide comprenant des composés de l'aluminium et des autres éléments cérium, terbium et Mg et le cœur minéral; a liquid mixture is formed comprising compounds of aluminum and the other elements cerium, terbium and Mg and the mineral core;
- on sèche par atomisation ledit mélange; said mixture is spray-dried;
- on calcine le produit séché à une température comprise entre 700°C et 950°C. the dried product is calcined at a temperature of between 700 ° C. and 950 ° C.
Comme indiqué plus haut, ce procédé comporte une première étape dans laquelle on forme un mélange liquide qui est une solution ou une suspension ou encore un gel, des composés de l'aluminium et des autres éléments cérium, terbium et Mg, ce mélange comprenant en outre le cœur minéral. Ce mélange peut aussi comprendre les éléments substituants qui ont été mentionnés plus haut. As indicated above, this process comprises a first step in which a liquid mixture is formed which is a solution or a suspension or a gel, compounds of aluminum and other elements cerium, terbium and Mg, this mixture comprising in part besides the mineral heart. This mixture may also include the substituent elements which have been mentioned above.
Comme composés des éléments aluminium, cérium, terbium, Mg et éventuellement substituant, on utilise habituellement des sels inorganiques ou encore les hydroxydes. Comme sels on peut mentionner les nitrates de préférence, notamment pour l'aluminium, l'europium et le magnésium. Les sulfates, notamment pour l'aluminium, les chlorures ou encore les sels organiques, par exemple les acétates, peuvent éventuellement être employés.
On peut utiliser aussi comme composé de l'aluminium un sol ou dispersion colloïdale d'aluminium. Une telle dispersion colloïdale d'aluminium peut présenter des particules ou colloïdes dont la taille est comprise entre 1 nm et 300 nm. L'aluminium peut être présent dans le sol sous forme de boehmite. As compounds of aluminum, cerium, terbium, Mg and optionally substituent elements, inorganic salts or hydroxides are usually used. As salts, mention may be made of nitrates preferably, in particular for aluminum, europium and magnesium. Sulfates, especially for aluminum, chlorides or organic salts, for example acetates, may optionally be employed. It is also possible to use as aluminum compound a sol or colloidal dispersion of aluminum. Such a colloidal dispersion of aluminum may have particles or colloids whose size is between 1 nm and 300 nm. Aluminum can be present in the soil as boehmite.
L'étape suivante consiste à sécher le mélange préalablement préparé. Ce séchage se fait par atomisation. The next step is to dry the previously prepared mixture. This drying is done by atomization.
On entend par séchage par atomisation un séchage par pulvérisation du mélange dans une atmosphère chaude (spray-drying). L'atomisation peut être réalisée au moyen de tout pulvérisateur connu en soi, par exemple par une buse de pulvérisation du type pomme d'arrosoir ou autre. On peut également utiliser des atomiseurs dits à turbine. Sur les diverses techniques de pulvérisation susceptibles d'être mises en œuvre dans le présent procédé, on pourra se référer notamment à l'ouvrage Handbook of Industrial Drying, Chapitre 10 Industrial spray-drying Systems, Arun S,. Numjumbar 2007. Spray drying is understood to mean spray drying of the mixture in a hot atmosphere (spray-drying). The atomization can be carried out using any sprayer known per se, for example by a spraying nozzle of the watering apple or other type. It is also possible to use so-called turbine atomizers. On the various spraying techniques that may be used in the present process, reference may be made in particular to Handbook of Industrial Drying, Chapter 10 Industrial spray-drying Systems, Arun S ,. Numjumbar 2007.
La dernière étape du procédé consiste à calciner le produit obtenu à l'issue du séchage. The last step of the process consists of calcining the product obtained after drying.
La calcination se fait à une température comprise entre 700°C et 950°C, plus particulièrement entre 700°C et 900°C. The calcination is carried out at a temperature of between 700 ° C. and 950 ° C., more particularly between 700 ° C. and 900 ° C.
La calcination se fait généralement sous air. Calcination is usually done under air.
Le composé précurseur de l'invention est obtenu à l'issue de cette calcination. The precursor compound of the invention is obtained at the end of this calcination.
Le procédé de préparation des luminophores The process of preparation of phosphors
Les luminophores de l'invention sont obtenus par calcination à une température d'au moins 1200°C des compositions ou précurseurs tels que décrits plus haut ou des compositions ou précurseurs obtenus par le procédé qui a aussi été décrit précédemment. On notera qu'il s'agit là d'une température plus basse que celle nécessaire pour la préparation d'un luminophore par voie chamottage. Cette température peut être plus particulièrement d'au moins 1400°C. Par ce traitement, les compositions ou précurseurs sont transformés en luminophores efficaces. The luminophores of the invention are obtained by calcination at a temperature of at least 1200 ° C. of the compositions or precursors as described above or of the compositions or precursors obtained by the process which has also been described above. It will be noted that this is a lower temperature than that required for the preparation of a phosphor by firing. This temperature may be more particularly at least 1400 ° C. By this treatment, the compositions or precursors are converted into effective phosphors.
Bien que, comme on l'a indiqué plus haut, les précurseurs puissent eux- mêmes présenter des propriétés intrinsèques de luminescence, ces propriétés sont généralement insuffisantes pour les applications visées et elles sont grandement améliorées par le traitement de calcination. Although, as mentioned above, the precursors themselves may have intrinsic luminescence properties, these properties are generally insufficient for the intended applications and are greatly improved by the calcination treatment.
La calcination peut se faire sous air, sous gaz inerte mais aussi et de préférence sous atmosphère réductrice (H2, N2/H2 ou Ar/H2 par exemple) afin,
dans ce dernier cas, de convertir l'ensemble des espèces Ce et Tb à leur état d'oxydation (+111). The calcination can be carried out under air, under an inert gas but also and preferably under a reducing atmosphere (H 2 , N 2 / H 2 or Ar / H 2 for example) in order to in the latter case, to convert all the species Ce and Tb to their oxidation state (+111).
De manière connue, la calcination peut se faire en présence d'un flux ou agent fondant de type fluorure comme, par exemple, le fluorure de lithium, d'aluminium ou de magnésium. In known manner, the calcination can be carried out in the presence of a flux or fluxing agent of the fluoride type, such as, for example, lithium, aluminum or magnesium fluoride.
Il est aussi possible de conduire la calcination en absence de tout flux donc sans mélange préalable de l'agent fondant avec le précurseur. It is also possible to conduct the calcination in the absence of any flux, thus without prior mixing of the melting agent with the precursor.
Après traitement, les particules sont avantageusement lavées, de manière à obtenir un luminophore le plus pur possible et dans un état désaggloméré ou faiblement aggloméré. Dans ce dernier cas, il est possible de désagglomérer le luminophore en lui faisant subir un traitement de désagglomération dans des conditions douces, du type broyage à billes par exemple. After treatment, the particles are advantageously washed, so as to obtain the purest phosphor possible and in a deagglomerated or weakly agglomerated state. In the latter case, it is possible to deagglomerate the phosphor by subjecting it to deagglomeration treatment under mild conditions, such as ball milling.
Les traitements thermiques précités permettent d'obtenir des luminophores qui conservent une structure cœur/coquille et une distribution granulométrique proches de celles des particules du précurseur. The aforementioned heat treatments make it possible to obtain luminophores which retain a core / shell structure and a particle size distribution close to those of the precursor particles.
En outre, le traitement thermique peut être conduit sans induire des phénomènes sensibles de diffusion des espèces Ce et Tb de la couche externe du luminophore vers le cœur. In addition, the heat treatment can be conducted without inducing sensitive phenomena of diffusion of the species Ce and Tb from the outer layer of the phosphor to the core.
Selon un mode de réalisation spécifique envisageable de l'invention, il est possible de conduire en une seule et même étape le traitement thermique décrit pour la préparation du précurseur et la calcination pour la transformation du précurseur en luminophore. Dans ce cas, on obtient directement le luminophore sans s'arrêter au précurseur. According to a specific embodiment that can be envisaged of the invention, it is possible to conduct in a single step the heat treatment described for the preparation of the precursor and the calcination for the conversion of the precursor into a phosphor. In this case, the phosphor is obtained directly without stopping at the precursor.
Les luminophores de l'invention peuvent être utilisés comme lumlinophores verts et ils peuvent ainsi entrer dans la fabrication de tout appareil incorporant des luminophores comme des lampes trichromatiques, des diodes électroluminescentes et des écrans à plasma. The phosphors of the invention can be used as green lumlinophores and can thus be used in the manufacture of any apparatus incorporating phosphors such as trichromatic lamps, light-emitting diodes and plasma screens.
Ils peuvent être également utilisés dans des systèmes de marquage à excitation UV. They can also be used in UV excitation labeling systems.
Ils peuvent également être dispersés dans des matrices organiques (par exemple, des matrices plastiques ou des polymères transparents sous UV ... ), minérales (par exemple de la silice) ou hybrides organo-minérales. They can also be dispersed in organic matrices (for example, plastic matrices or transparent polymers under UV ...), mineral (for example silica) or organo-mineral hybrids.
L'invention concerne en conséquence un dispositif de type lampe trichromatique, diode électroluminescente ou écran à plasma comprenant le luminophore de l'invention ou un dispositif du même type qui est fabriqué en utilisant le luminophore de l'invention.
La mise en œuvre de ce luminophore dans la fabrication des dispositifs décrits ci-dessus se fait selon des techniques bien connues, par exemple par sérigraphie, par pulvérisation, par électrophorèse, par sédimentation ou par trempage (deep coating). The invention accordingly relates to a device of the trichromatic lamp type, light emitting diode or plasma screen comprising the phosphor of the invention or a device of the same type which is manufactured using the phosphor of the invention. The use of this phosphor in the manufacture of the devices described above is done according to well-known techniques, for example by screen printing, by spraying, by electrophoresis, by sedimentation or by soaking (deep coating).
Des exemples vont maintenant être donnés. Examples will now be given.
Dans ces exemples on utilise les réactifs suivants : In these examples, the following reagents are used:
- boehmite à 73,5% en Al203 - 73.5% boehmite in Al 2 0 3
- solution de Ce(N03)3 à 2,88 M solution of Ce (N0 3 ) 3 at 2.88 M
- solution de Tb(N03)3 à 2,6 Msolution of Tb (N0 3 ) 3 at 2.6 M
- Alumine de type alumine alpha, de morphologie sphérique, D50 = 3 pm (granulométrie laser), surface BET < 1 m2/g Alumina of the alpha alumina type, of spherical morphology, D 50 = 3 μm (laser particle size), BET surface area <1 m 2 / g
Rendement de luminescence Luminescence efficiency
Les mesures du rendement de photoluminescence (PL) des luminophores sont faites par intégration du spectre d'émission entre 450 nm et 700 nm, sous excitation à 254 nm, en utilisant un spectrophotomètre Jobin - Yvon. Le rendement de photoluminescence de l'exemple 1 est pris comme référence avec une valeur de 100. The photoluminescence (PL) efficiency measurements of phosphors are made by integration of the emission spectrum between 450 nm and 700 nm, under excitation at 254 nm, using a Jobin - Yvon spectrophotometer. The photoluminescence yield of Example 1 is taken as a reference with a value of 100.
Microscopie électronique Electron microscopy
Les clichés de microscopie électronique à transmission sont réalisés sur une coupe (microtomie) des particules, en utilisant un microscope MEB. La résolution spatiale de l'appareil pour les mesures de composition chimique par EDS (spectroscopie à dispersion en énergie) est < 2 nm. La corrélation des morphologies observées et des compositions chimiques mesurées permet de mettre en évidence la structure cœur-coquille et de mesurer sur les clichés l'épaisseur de la coquille. The transmission electron micrographs are made on a section (microtomy) of the particles, using a SEM microscope. The spatial resolution of the apparatus for chemical composition measurements by EDS (energy dispersive spectroscopy) is <2 nm. The correlation of observed morphologies and measured chemical compositions makes it possible to highlight the core-shell structure and to measure the thickness of the shell on the plates.
Les mesures de composition chimique peuvent être réalisées aussi par EDS sur des clichés effectués par STEM HAADF. La mesure correspond à une moyenne effectuée sur au moins deux spectres. The measurements of chemical composition can also be carried out by EDS on plates made by STEM HAADF. The measurement corresponds to an average performed on at least two spectra.
EXEMPLE 1 COMPARATIF EXAMPLE 1 COMPARATIVE
Cet exemple concerne un produit selon l'art antérieur de formule (Ce0,67Tbo,33)MgAI11019. This example relates to a product according to the prior art of formula (It 0 67Tbo, 33) MgAl 11 0 19.
a) Préparation du précurseur a) Preparation of the precursor
On mélange 100 g de boehmite avec 1 L d'eau sous agitation. Le pH de la suspension est alors de 5. On ajoute 19,08 g d'HNO3 à 5 mol/L pour descendre à un pH de 2, on laisse reposer la suspension 24 h et on obtient un sol stable de boehmite.
On mélange respectivement 52,3 g et 28,8 g des solutions de nitrates de cérium et de terbium ainsi que 33,6 g de nitrate de magnésium. 100 g of boehmite are mixed with 1 L of water with stirring. The pH of the suspension is then 5. 19.08 g of 5 mol / l HNO 3 are added to bring the pH down to 2, the suspension is allowed to stand overnight and a stable boehmite sol is obtained. 52.3 g and 28.8 g of solutions of nitrates of cerium and terbium and 33.6 g of magnesium nitrate are respectively mixed.
On ajoute le mélange obtenu dans le sol de boehmite et on ajoute de l'eau de manière à ce que l'extrait sec de la suspension soit inférieur à 7%. The resulting mixture is added to the boehmite sol and water is added so that the solids content of the suspension is less than 7%.
La suspension est ensuite atomisée au Buchi (T entrée : 250°C et T sortie : 1 15°C). Le solide est ensuite calciné à 900°C pendant 2 h sous air b) Préparation du luminophore The suspension is then atomized with Buchi (T inlet: 250 ° C and T outlet: 1 15 ° C). The solid is then calcined at 900 ° C. for 2 hours in air. B) Preparation of the phosphor
A 15 g du précurseur synthétisé ci-dessus, on ajoute 0, 1283 g de MgF2 (soit 10% mol/mol) et on mélange pendant 30 minutes. To 15 g of the precursor synthesized above, 0, 1283 g of MgF 2 (ie 10 mol / mol) is added and mixed for 30 minutes.
On transfère ensuite dans un creuset et on calcine sous atmosphère réductrice (Ar/H2 à 5%) à 1470°C pendant 2 heures. It is then transferred to a crucible and calcined under a reducing atmosphere (Ar / H 2 at 5%) at 1470 ° C. for 2 hours.
On lave ensuite le produit obtenu avec 300 ml d'eau chaude à 80°C pendant 3 h, on filtre et on sèche à l'étuve. EXEMPLE 2 The product obtained is then washed with 300 ml of hot water at 80 ° C. for 3 hours, filtered and dried in an oven. EXAMPLE 2
Cet exemple concerne un produit de type cœur/coquille selon l'invention et dont le coeur est en alumine et dont la coquille répond à la formule (Ce0,67Tbo,33)MgAI11019. This example relates to a core / shell type product according to the invention and whose core is alumina and whose shell corresponds to the formula (Ce 0 , 67Tbo, 33) MgAI 11 0 19 .
a) Préparation du précurseur a) Preparation of the precursor
On mélange 49,4 g de boehmite avec 0,3L d'eau sous agitation. Le pH de la suspension est alors de 5. On ajoute 9,3 g d'HNO3 à 5 mol/L pour descendre à un pH de 2, on laisse reposer la suspension 24 h et on obtient un sol stable de boehmite. 49.4 g of boehmite are mixed with 0.3L of water with stirring. The pH of the suspension is then 5. 9.3 g of 5 mol / l HNO 3 are added to bring the pH down to 2, the suspension is allowed to stand overnight and a stable boehmite sol is obtained.
On mélange respectivement 25,8 g et 14,2 g des solutions de nitrates de cérium et de terbium ainsi que 16,6 g de nitrate de magnésium. 25.8 g and 14.2 g of solutions of nitrates of cerium and terbium and 16.6 g of magnesium nitrate are respectively mixed.
On ajoute le mélange obtenu dans le sol de boehmite. On ajoute aussi 0,8 I d'eau puis 4,4 g d'alumine à titre de cœur de telle sorte que le ratio molaire cœur/coquille soit de 40% de cœur et 60% de coquille. The resulting mixture is added to the boehmite sol. 0.8 l of water and then 4.4 g of alumina are also added as the core, so that the core / shell molar ratio is 40% of the core and 60% of the shell.
La suspension est ensuite atomisée au Buchi (T entrée : 250°C et T sortie : 1 15°C). Le solide est ensuite calciné à 900°C pendant 2 h sous air. b) Préparation du luminophore The suspension is then atomized with Buchi (T inlet: 250 ° C and T outlet: 1 15 ° C). The solid is then calcined at 900 ° C. for 2 hours in air. b) Preparation of the phosphor
A 15 g du précurseur synthétisé ci-dessus, on ajoute 0, 1283 g de MgF2 (soit 10% mol/mol ou 0,8% w/w) et on mélange pendant 30 minutes au turbula. To 15 g of the precursor synthesized above, 0, 1283 g of MgF2 (that is to say 10 mol% / mol or 0.8% w / w) are added and the turbula is mixed for 30 minutes.
On transfère ensuite dans un creuset rectangulaire et on calcine sous atmosphère réductrice (Ar/H2 à 5%) à 1470°C pendant 2 heures. It is then transferred to a rectangular crucible and calcined under a reducing atmosphere (Ar / H 2 at 5%) at 1470 ° C. for 2 hours.
On lave ensuite le produit obtenu avec 300 ml d'eau chaude à 80°C pendant 3h, on filtre et on sèche à l'étuve.
On donne dans le tableau ci-dessous les caractéristiques des produits obtenus dans les exemples précédents. The product obtained is then washed with 300 ml of hot water at 80 ° C. for 3 hours, filtered and dried in an oven. The characteristics of the products obtained in the preceding examples are given in the table below.
* R désigne le rapport massique en terbium par rapport au luminophore exprimé en g de Tb4O7 par rapport à la masse du luminophore en kg. * R denotes the mass ratio of terbium relative to the phosphor expressed in g of Tb 4 O 7 relative to the mass of the phosphor in kg.
L'examen par MEB classique sur un nombre représentatif de clichés des précurseur et luminophore de l'exemple 2 ne fait pas apparaître la présence de particules de cœur d'alumine. The conventional SEM examination on a representative number of precursor and phosphor plates of Example 2 does not reveal the presence of alumina core particles.
Les précurseur et luminophore de l'exemple 2 présentent par ailleurs par observation en MEB sur une coupe de produit une morphologie typique de type cœur-coquille. The precursor and phosphor of Example 2 also show by observation in SEM on a product section a typical morphology heart-shell type.
On constate à partir des résultats du tableau que le produit de l'invention bien que présentant un taux en terbium inférieur à celui du produit comparatif offre un rendement de luminescence légèrement supérieur.
It can be seen from the results of the table that the product of the invention, although having a lower terbium content than that of the comparative product, offers a slightly higher luminescence yield.
Claims
REVENDICATIONS
1 - Composition caractérisée en ce qu'elle comprend : 1 - Composition characterized in that it comprises:
- un cœur minéral; - a mineral heart;
- une coquille à base d'un aluminate de formule : a shell based on an aluminate of formula:
(CeaTbb)lvlg1 +xAI11 +yOi9+x+y (1 ) (This at Tbb) lvlg 1 + xAI 11 + yOi9 + x + y (1)
dans laquelle a, b, x et y vérifient les relations : where a, b, x, and y satisfy the relationships:
a+b=1 a + b = 1
-0,2 < x < +0,2 -0.2 <x <+0.2
-0,2 < y < +0,2 -0.2 <y <+0.2
et recouvrant de façon homogène le cœur minéral sur une épaisseur égale ou supérieure à 300 nm. and homogeneously overlying the mineral core to a thickness equal to or greater than 300 nm.
2- Composition selon la revendication 1 , caractérisée en ce que la coquille recouvre le cœur sur une épaisseur égale ou inférieure à 2000 nm, plus particulièrement comprise entre 750 nm et 1500 nm. 3- Composition selon la revendication 1 ou 2, caractérisée en ce que l'aluminate répond à la formule (1 ) dans laquelle x = y = 0. 2- Composition according to claim 1, characterized in that the shell covers the core to a thickness equal to or less than 2000 nm, more particularly between 750 nm and 1500 nm. 3. Composition according to claim 1 or 2, characterized in that the aluminate corresponds to formula (1) in which x = y = 0.
4- Composition selon l'une des revendications précédentes, caractérisée en ce que le cœur minéral est choisi parmi l'alumine, la zircone, éventuellement dopée, les aluminates de métaux alcalino-terreux, notamment les aluminates de magnésium. 4- Composition according to one of the preceding claims, characterized in that the mineral core is selected from alumina, zirconia, optionally doped, alkaline earth metal aluminates, especially magnesium aluminates.
5- Luminophore caractérisé en ce qu'il comprend : 5- phosphor characterized in that it comprises:
- un cœur minéral; - a mineral heart;
- une coquille à base d'un aluminate de formule : a shell based on an aluminate of formula:
(CeaTbb)lvlg1 +xAI11 +yOi9+x+y (1 ) (This at Tbb) lvlg 1 + xAI 11 + yOi9 + x + y (1)
dans laquelle a, b, x et y vérifient les relations : where a, b, x, and y satisfy the relationships:
a+b=1 a + b = 1
-0,2 < x < +0,2 -0.2 <x <+0.2
-0,2 < y < +0,2 -0.2 <y <+0.2
et recouvrant de façon homogène le cœur minéral sur une épaisseur égale ou supérieure à 300 nm.
6- Luminophore selon la revendication 5, caractérisé en ce que la coquille recouvre le cœur sur une épaisseur égale ou inférieure à 2000 nm, plus particulièrement comprise entre 750 nm et 1500 nm. 7- Luminophore selon la revendication 5 ou 6, caractérisé en ce que l'aluminate répond à la formule (1 ) dans laquelle x = y = 0. and homogeneously overlying the mineral core to a thickness equal to or greater than 300 nm. 6. The phosphor according to claim 5, characterized in that the shell covers the core to a thickness equal to or less than 2000 nm, more particularly between 750 nm and 1500 nm. 7- phosphor according to claim 5 or 6, characterized in that the aluminate corresponds to the formula (1) wherein x = y = 0.
8- Procédé de préparation d'une composition selon l'une des revendications 1 à 4, caractérisé en ce qu'il comporte les étapes suivantes : 8- Process for preparing a composition according to one of claims 1 to 4, characterized in that it comprises the following steps:
- on forme un mélange liquide comprenant des composés de l'aluminium et des autres éléments cérium, terbium et Mg et le cœur minéral; a liquid mixture is formed comprising compounds of aluminum and the other elements cerium, terbium and Mg and the mineral core;
- on sèche par atomisation ledit mélange; said mixture is spray-dried;
- on calcine le produit séché à une température comprise entre 700°C et 950°C. the dried product is calcined at a temperature of between 700 ° C. and 950 ° C.
9- Procédé selon la revendication 8, caractérisé en ce qu'on utilise comme composé de l'aluminium un sol de cet élément. 9- Method according to claim 8, characterized in that the compound of aluminum used a soil of this element.
10- Procédé de préparation d'un luminophore selon l'une des revendications 5 à 7, caractérisé en ce qu'on calcine à une température d'au moins 1200°C une composition selon l'une des revendications 1 à 4 ou une composition obtenue par le procédé selon la revendication 8 ou 9. 10- A process for preparing a luminophore according to one of claims 5 to 7, characterized in that calcined at a temperature of at least 1200 ° C a composition according to one of claims 1 to 4 or a composition obtained by the process according to claim 8 or 9.
1 1 - Dispositif du type lampes trichromatique, diode électroluminescente ou écran à plasma caractérisé en ce qu'il comprend, ou en ce qu'il est fabriqué en utilisant, un luminophore selon l'une des revendications 5 à 7 ou un luminophore obtenu par le procédé de la revendication 10.
1 1 - Device of the trichromatic lamp type, light emitting diode or plasma screen characterized in that it comprises, or in that it is manufactured using, a phosphor according to one of claims 5 to 7 or a phosphor obtained by the process of claim 10.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1004859A FR2968649B1 (en) | 2010-12-14 | 2010-12-14 | ALUMINATE COMPOSITION, HEART / SHELL TYPE, LUMINOPHORE THEREOF AND METHODS FOR PREPARING THE SAME |
PCT/EP2011/069851 WO2012079863A1 (en) | 2010-12-14 | 2011-11-10 | Composition containing a core-shell aluminate, phosphor obtained from said composition, and preparation methods |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2652079A1 true EP2652079A1 (en) | 2013-10-23 |
Family
ID=43629277
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP11781538.1A Withdrawn EP2652079A1 (en) | 2010-12-14 | 2011-11-10 | Composition containing a core-shell aluminate, phosphor obtained from said composition, and preparation methods |
Country Status (8)
Country | Link |
---|---|
US (2) | US9290693B2 (en) |
EP (1) | EP2652079A1 (en) |
JP (1) | JP2014506266A (en) |
KR (1) | KR101529405B1 (en) |
CN (1) | CN103261367B (en) |
CA (1) | CA2816385A1 (en) |
FR (1) | FR2968649B1 (en) |
WO (1) | WO2012079863A1 (en) |
Families Citing this family (5)
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FR2968649B1 (en) * | 2010-12-14 | 2015-05-01 | Rhodia Operations | ALUMINATE COMPOSITION, HEART / SHELL TYPE, LUMINOPHORE THEREOF AND METHODS FOR PREPARING THE SAME |
TW201925419A (en) | 2017-09-18 | 2019-07-01 | 德商馬克專利公司 | Multicomponent luminophores as colour converters for solid-state light sources |
US11015032B2 (en) | 2018-03-02 | 2021-05-25 | Seton Hall University | Photoactive polymer coatings |
CN108329907A (en) * | 2018-03-27 | 2018-07-27 | 深圳科尔新材料科技有限公司 | Hard template sol-gal process prepares long-persistence luminous nano material |
CN114921244B (en) * | 2022-05-24 | 2023-07-04 | 营口理工学院 | Spindle rod-shaped MgAl 2 O 4 :Tb 3+ Fluorescent powder and preparation method thereof |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
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US5518808A (en) | 1992-12-18 | 1996-05-21 | E. I. Du Pont De Nemours And Company | Luminescent materials prepared by coating luminescent compositions onto substrate particles |
ES2258527T3 (en) * | 2000-05-05 | 2006-09-01 | Bayer Technology Services Gmbh | NANOPARTICLES IMPURIFIED AS BIOMARKERS. |
JP3695744B2 (en) | 2001-07-11 | 2005-09-14 | 松下電器産業株式会社 | Composite phosphor and fluorescent lamp using the same |
EP1403329A1 (en) * | 2002-09-27 | 2004-03-31 | Fuji Photo Film Co., Ltd. | Method for coating particles |
CN1485397A (en) * | 2002-09-29 | 2004-03-31 | 邱新萍 | Method for manufacturing luminous composition |
EP1473347B1 (en) | 2003-04-30 | 2006-11-29 | Nanosolutions GmbH | Core/shell nanoparticles suitable for (F) RET-assays |
FR2855169B1 (en) * | 2003-05-23 | 2006-06-16 | Rhodia Elect & Catalysis | PRECURSOR COMPOUNDS OF ALKALINO-EARTH OR RARE EARTH ALUMINATES, PROCESS FOR THEIR PREPARATION AND THEIR USE AS A LUMINOPHORE PRECURSOR, IN PARTICULAR |
US20070212541A1 (en) * | 2006-03-07 | 2007-09-13 | Kazuya Tsukada | Core/shell type particle phosphor |
FR2904323B1 (en) * | 2006-07-28 | 2008-10-31 | Rhodia Recherches & Tech | LUMINOPHORES HEART-SHELL. |
FR2943658B1 (en) | 2009-03-24 | 2011-07-22 | Rhodia Operations | COMPOSITION COMPRISING A CERIUM PHOSPHATE AND / OR TERBIUM, HEART / SHELL TYPE, LUMINOPHORE THEREOF AND METHODS FOR PREPARING THE SAME |
DE202009008015U1 (en) | 2009-04-07 | 2010-10-07 | InBio Prof.Jürgen Büddefeld Dr.Peter Klauth Prof.Manfred Rietz GbR (vertretungsberechtigter Gesellschafter: Dr.Peter Klauth, 41189 Mönchengladbach) | Modification of phyllosilicates for luminescence activation |
FR2968649B1 (en) * | 2010-12-14 | 2015-05-01 | Rhodia Operations | ALUMINATE COMPOSITION, HEART / SHELL TYPE, LUMINOPHORE THEREOF AND METHODS FOR PREPARING THE SAME |
-
2010
- 2010-12-14 FR FR1004859A patent/FR2968649B1/en not_active Expired - Fee Related
-
2011
- 2011-11-10 US US13/992,192 patent/US9290693B2/en not_active Expired - Fee Related
- 2011-11-10 CA CA2816385A patent/CA2816385A1/en not_active Abandoned
- 2011-11-10 KR KR1020137015230A patent/KR101529405B1/en not_active IP Right Cessation
- 2011-11-10 JP JP2013543596A patent/JP2014506266A/en active Pending
- 2011-11-10 CN CN201180058889.3A patent/CN103261367B/en not_active Expired - Fee Related
- 2011-11-10 EP EP11781538.1A patent/EP2652079A1/en not_active Withdrawn
- 2011-11-10 WO PCT/EP2011/069851 patent/WO2012079863A1/en active Application Filing
-
2016
- 2016-02-26 US US15/055,502 patent/US20160251574A1/en not_active Abandoned
Non-Patent Citations (1)
Title |
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See references of WO2012079863A1 * |
Also Published As
Publication number | Publication date |
---|---|
KR20130086242A (en) | 2013-07-31 |
CA2816385A1 (en) | 2012-06-21 |
US20160251574A1 (en) | 2016-09-01 |
FR2968649A1 (en) | 2012-06-15 |
CN103261367A (en) | 2013-08-21 |
KR101529405B1 (en) | 2015-06-16 |
US9290693B2 (en) | 2016-03-22 |
CN103261367B (en) | 2015-03-11 |
JP2014506266A (en) | 2014-03-13 |
FR2968649B1 (en) | 2015-05-01 |
WO2012079863A1 (en) | 2012-06-21 |
US20130313479A1 (en) | 2013-11-28 |
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