CN102585824A - Coprecipitation-rheological phase preparation method of rare earth doped yttrium aluminum garnet fluorescent powder - Google Patents

Abstract

The invention relates to _a co-precipitation-rheological phase preparation method of rare earth-doped yttrium aluminum garnet fluorescent powder. Body and dispersant are adjusted to rheological phase, and then undergo high temperature heat treatment to wash and remove impurities in phosphor powder; use ammonium sulfate, polyethylene glycol, hydroxycellulose or dodecyltrimethylammonium bromide as dispersant, deionized Water, ethanol, acetic acid, or oxalic acid are used as rheological phase solvents. The purpose of adding seed crystals is to reduce the activation energy of the reaction and increase the luminous intensity through doping; it is suitable for LED phosphors, trichromatic phosphors, long afterglow phosphors and Preparation of PDP fluorescent powder; the particle size of the phosphor powder produced in the present invention is between nanometer and micron, which can be adjusted by seed crystal and calcination temperature; the method is simple, the equipment cost is low, and the processing capacity is large, which is suitable for various indications and displays Or the preparation of fluorescent powder for lighting.

Description

Co-precipitation-rheological phase preparation method of rare earth doped yttrium aluminum garnet phosphor

technical field

The present invention relates to a preparation method of fluorescent powder, in particular to a co-precipitation-rheological phase preparation method of rare earth-doped yttrium aluminum garnet fluorescent powder which can be effectively excited by ultraviolet light, purple light or blue light. The nanometer and micrometer YAG, SiO ₂ or SiC etc. are used as seed crystals, prepared by co-precipitation-rheological phase method, and the phosphor powder can be widely used in white light-emitting diodes (LEDs).

Background technique

Phosphor powder is one of the key materials in the field of display and lighting. The performance of the powder is mainly determined by its phase structure, particle morphology and luminescence characteristics. In order to prepare high-quality phosphors, innovations in preparation methods are required.

A lot of research has been done on the preparation method of phosphor powder at home and abroad. Regarding the preparation of yttrium aluminum garnet phosphor, the phosphor powder was synthesized by high temperature solid phase method (ZL 02800161.3) in the early stage. The phosphor powder preparation method reported at present mainly contains precipitation method (CN 101134896A, ZL 200510071958.0, ZL 02130949.3, ZL 98124953.1, US 20060145124, US 6869544, US 20040173807, US 4034257, US/6491793) (sol-gel method) ZL 02136705.1), hydrothermal method (ZL03112160.8), microemulsion method (ZL 200710118422.9), combustion method, gas phase method (ZL 200510122254.1), etc. The solid-phase method has large particle size and poor uniformity; the raw material cost is high and the yield is low in the sol-gel method preparation process; other methods also have the following defects: the light decay, brightness and coating performance cannot be improved at the same time. The precipitation method can make up for the shortcomings of the above methods.

Contents of the invention

The object of the present invention is to provide a co-precipitation-rheological phase preparation method of rare earth-doped yttrium aluminum garnet phosphor, that is, with regular-shaped nanometer or micron YAG, SiO ₂ or SiC, etc. as crystal seeds, with co-precipitation-rheological phase preparation method. Y ₃ Al ₅ O ₁₂ :Ce phosphor is prepared by rheological phase method. The product has regular shape, particle size (d ₅₀ ) of 0.1-20 μ, uniform particle size distribution, stable chemical properties, good luminescence performance, and can be effectively excited by blue light.

Technical scheme of the present invention is as follows:

Co-precipitation-rheological phase preparation method of rare earth-doped yttrium aluminum garnet (Y ₃ Al ₅ O ₁₂ :Ce) fluorescent powder provided by the present invention, which uses regular-shaped nano or micro YAG, SiO ₂ or SiC as crystal seeds , using co-precipitation-rheological phase method to prepare rare earth-doped yttrium aluminum garnet phosphor; the preparation steps are as follows:

1) Preparation of Y ₃ Al ₅ O ₁₂ :Ce phosphor precursor:

1.1) Preparation of metal ion mixture:

Weigh the metal oxide powder with a purity of 4N-7N according to the stoichiometric ratio and add it to water to prepare a metal oxide suspension, then add concentrated nitric acid, heat until the metal oxide powder is completely dissolved, and prepare a concentration of 0.02 to 0.15 A mixed solution with a mol/l pH value of 6-7, and then adding Al(NO ₃ ) ₃ to the mixed solution according to the stoichiometric ratio to obtain a mixed solution of metal ions; the metal oxide powder is yttrium oxide powder Mixed powder with cerium oxide powder;

1.2) preparing a precipitant solution with a concentration of 1.0 to 3.0mol/l, the precipitant being at least one of ammonium bicarbonate solution, urea, ammonia and oxalic acid solution;

1.3) Preparation of metal ion precipitate:

Add the metal ion mixture solution in step 1.1) to the precipitant solution prepared in step 1.2) at a rate of 1ml/min to 10ml/min, carry out a precipitation reaction, and stand and age to obtain a precipitate;

The molar ratio of the total number of moles of metal ions in the metal ion mixture to the number of moles of the precipitant in the precipitant solution is 1:20;

1.4) Wash the obtained precipitate with deionized water and absolute ethanol in turn to obtain a white Y ₃ Al ₅ O ₁₂ :Ce phosphor precursor, and dry the Y ₃ Al ₅ O ₁₂ :Ce phosphor precursor deal with;

2) Mix the seed crystal with the Y ₃ Al ₅ O ₁₂ :Ce phosphor precursor of step 1.4), add a dispersant to the mixture, and mix it with a solvent, adjust the mixture to the rheological phase, and The rheological phase mixture is dried;

The described seed crystal is YAG seed crystal, SiO ₂ crystal seed or SiC seed crystal;

The dispersant is at least one of ammonium sulfate, polyethylene glycol, hydroxycellulose and dodecyltrimethylammonium bromide;

The solvent is deionized water, ethanol, acetic acid or oxalic acid;

The weight ratio of the seed crystal, the dispersant and the Y ₃ Al ₅ O ₁₂ :Ce phosphor precursor is 0.1-5:0.1-0.5:100;

3) Add 1-20wt% flux of the total weight of the rheological phase mixture to the dried rheological phase mixture in step 2), grind and mix uniformly to form a mixture, and carry out the mixture in a reducing atmosphere roasting to obtain a roasted product, the roasting temperature is 900°C to 1600°C;

The flux is at least one of alkali metal halides, alkaline earth metal halides, boric acid, ammonium halides, alkali metal carbonates and alkaline earth metal carbonates;

4) The roasted product obtained in step 3) is washed, impurity removed, dried and classified in sequence to prepare the rare earth-doped yttrium aluminum garnet phosphor.

The grinding in the step 3) is performed in ethanol, acetone or water. The calcination time of the step 4) is 2 to 30 hours. The impurity removal of the roasted product in the step 4) is acid washing, alkali washing or water washing. The classification of the roasted product in the step 4) is one of sedimentation method classification, sieving method classification, hydraulic classification method classification and air flow classification method classification or several mixed classifications.

The co-precipitation-rheological phase preparation method of rare earth-doped yttrium aluminum garnet phosphor provided by the present invention has the following characteristics:

The method of the present invention is to add uniform nanometer or micron inorganic particles into the co-precipitation precursor as the crystal seed of the precipitation reaction, add various surfactants at the same time, and add a solvent to adjust the rheological phase, and the obtained rare earth doped yttrium aluminum garnet Phosphor powder has regular shape, uniform particle size, particle size (d ₅₀ ) of 0.1-20μ, uniform particle size distribution, stable chemical properties, good luminous performance, and can be effectively excited by blue light; it can be applied to blue LED chips.

Detailed ways

The present invention is further described below through specific examples, but the protection scope of the present invention is not limited by these examples.

Example 1

The rare earth-doped yttrium aluminum garnet fluorescent powder whose molecule is Y ₃ Al ₅ O ₁₂ : Ce is prepared, and the preparation steps are as follows:

Weigh 3.331gY ₂ O ₃ (4N) and 0.086gCeO ₂ (4N) into water, heat and dissolve it with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.08mol/l and a pH of 6. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Weigh 6.320g of NH ₄ HCO ₃ to prepare a precipitant solution with a concentration of 1.5mol/l;

At room temperature, add the mother salt solution dropwise (dropping rate 5ml/min) into the stirred _NH4HCO3 solution until all precipitates are formed; then wash the precipitates _with deionized water and absolute ethanol in sequence ; Obtain a white precipitate precursor, and dry the white precipitate precursor;

Mix 0.060g of 0.6um YAG seed crystal and 0.01g of dispersant (dodecyltrimethylammonium bromide) and add it to the above-mentioned white precipitate precursor, and adjust it to rheological state with ethanol;

The above rheological phase material was kept at 100°C for 6 hours to obtain a dried product;

Then add flux (0.060g sodium fluoride and 0.060g boric acid mixture) to the dried product for mixing; then bake at 1600°C for 2 hours in a reducing atmosphere (nitrogen-hydrogen mixed gas) to obtain a roasted product;

Then the obtained calcined product is subjected to jet crushing, pickling, alkali washing, water washing to remove impurities, drying and sedimentation classification, etc., to obtain YAG:Ce(Y ₃ Al ₅ O ₁₂ :Ce) rare earth doped with a particle size of about 1.5um. Yttrium aluminum garnet phosphor.

Comparative example 1

The rare earth-doped yttrium aluminum garnet fluorescent powder whose molecule is Y _2.95 Al ₅ O ₁₂ : Ce _0.05 is prepared as follows:

Weigh 3.331gY ₂ O ₃ (4N) and 0.086gCeO ₂ (4N) into water, heat and dissolve it with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.08mol/l and a pH of 6. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Weigh 6.320g of NH ₄ HCO ₃ to prepare a precipitant solution with a concentration of 1.5mol/l;

At room temperature, add the mother salt solution dropwise (dropping rate 5ml/min) into the stirred _NH4HCO3 solution until all precipitates are formed; then wash the precipitates _with deionized water and absolute ethanol in sequence ; Obtain a white precipitate precursor, and dry the white precipitate precursor;

0.060g of 0.6umYAG seed crystals and 0.01g of dispersant (dodecyltrimethylammonium bromide) are added to the above-mentioned precipitate precursor, and then fluxing agent (0.060g sodium fluoride and 0.060 g boric acid mixture) mixed grinding; then roasting at 1600°C for 2 hours in a reducing atmosphere (nitrogen-hydrogen mixed gas) to obtain a roasted product;

Then, the obtained calcined product is subjected to jet crushing, pickling, alkali washing, water washing to remove impurities, drying and sedimentation classification in sequence to obtain YAG:Ce phosphor with a particle size of about 2.5um.

Comparative example 2

Weigh 3.331gY ₂ O ₃ (4N) and 0.086gCeO ₂ (4N) into water, heat and dissolve it with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.08mol/l and a pH of 6. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Weigh 6.320g of NH ₄ HCO ₃ to prepare a precipitant solution with a concentration of 1.5mol/l;

At room temperature, add the mother salt solution dropwise (dropping rate 5ml/min) into the stirred _NH4HCO3 solution until all precipitates are formed; then wash the precipitates _with deionized water and absolute ethanol in sequence ; Obtain a white precipitate precursor, and dry the white precipitate precursor;

Add 0.01 g of dispersant (dodecyltrimethylammonium bromide) to the above-mentioned precipitate precursor, and adjust to rheological state with ethanol;

The above rheological phase material was kept at 100°C for 6 hours to obtain a dried product;

Then add flux (0.060g sodium fluoride and 0.060g boric acid mixture) to the dried product for mixing; then bake at 1600°C for 2 hours in a reducing atmosphere (nitrogen-hydrogen mixed gas) to obtain a roasted product;

Then, the obtained calcined product is subjected to jet crushing, pickling, alkali washing, water washing to remove impurities, drying and sedimentation classification in sequence to obtain YAG:Ce phosphor with a particle size of about 1.0 um.

The difference between embodiment 1 and two comparative examples is: embodiment 1 adopts coprecipitation-rheological phase method (add crystal seed) of the present invention, comparative example 1 uses coprecipitation method (adds crystal seed), and comparative example 2 uses coprecipitation Method - rheological phase method (no seed added).

The emission main peak wavelength and the relative luminous intensity of the fluorescent powder made in embodiment 1 and two comparative examples are shown in the following table:

samples Emission main peak wavelength (nm) Relative Luminous Intensity (%) Example 1 540 112 Comparative example 1 541 100 Comparative example 2 540 90

As can be seen from the above, the YAG:Ce phosphor prepared by the method of the present invention has regular shape, uniform particle size, is easy to coat, and can well meet the application requirements (stable chemical properties, good luminescence performance, and can be effectively excited by blue light. ); can be widely used in blue LED chips.

Example 2

The preparation molecule is Y ₃ Al ₅ O ₁₂ : Ce rare earth doped yttrium aluminum garnet phosphor, which is prepared as follows:

Weigh 3.331gY ₂ O ₃ (5N) and 0.086gCeO ₂ (5N) into water, heat and dissolve them with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.02mol/l and a pH of 7. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Weigh 6.320g of NH ₄ HCO ₃ to prepare a precipitant solution with a concentration of 1.0mol/l;

At room temperature, add the mother salt solution dropwise (dropping rate 1ml/min) into the stirred NH ₄ HCO ₃ solution until all precipitates are formed; then wash the precipitates with deionized water and absolute ethanol in sequence ; Obtain a white precipitate precursor, and dry the white precipitate precursor;

Add 0.30g of 0.05um SiC seed crystal and 0.006g of dispersant (polyethylene glycol) to the above precipitate precursor, and adjust to rheological state with deionized water;

The above rheological phase material was kept at 100°C for 6 hours to obtain a dried product;

Then add flux (0.120g sodium fluoride) to the dried product for mixed grinding; then bake at 900°C for 2 hours in a reducing atmosphere (nitrogen-hydrogen mixed gas) to obtain a roasted product;

Then, the obtained calcined product is subjected to jet crushing, pickling, alkali washing, water washing to remove impurities, drying and sedimentation classification in sequence to obtain YAG:Ce phosphor with a particle size of about 0.1 um.

Example 3

The preparation molecule is Y ₃ Al ₅ O ₁₂ : Ce rare earth doped yttrium aluminum garnet phosphor, which is prepared as follows:

Weigh 3.331gY ₂ O ₃ (6N) and 0.086gCeO ₂ (6N) into water, heat and dissolve them with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.15mol/l and a pH of 6. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Weigh 6.320g of NH ₄ HCO ₃ to prepare a precipitant solution with a concentration of 3.0mol/l;

At room temperature, add the mother salt solution dropwise (dropping rate 10ml/min) into the stirred NH ₄ HCO ₃ solution until all precipitates are formed; then wash the precipitates with deionized water and absolute ethanol in sequence ; Obtain a white precipitate precursor, and dry the white precipitate precursor;

Add 0.1um _SiO2 seed crystal 0.006g and dispersant (ammonium sulfate) 0.02g to the above-mentioned precipitate precursor, and adjust to rheological state with acetic acid;

The above rheological phase material was kept at 100°C for 6 hours to obtain a dried product;

Then add flux (0.120g boric acid) to the dried product for mixed grinding; then bake at 1200°C for 10 hours in a reducing atmosphere (nitrogen-hydrogen mixed gas) to obtain a roasted product;

Then, the obtained calcined product is subjected to jet crushing, pickling, alkali washing, water washing to remove impurities, drying and sedimentation classification in sequence to obtain YAG:Ce phosphor with a particle size of about 1.0 um.

Example 4

The preparation molecule is Y ₃ Al ₅ O ₁₂ : Ce rare earth doped yttrium aluminum garnet phosphor, which is prepared as follows:

Weigh 3.331gY ₂ O ₃ (7N) and 0.086gCeO ₂ (7N) into water, heat and dissolve them with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.08mol/l and a pH of 6. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Take by weighing 9.612g urea, be mixed with the precipitant solution that concentration is 1.5mol/l;

At room temperature, the mother salt solution was added dropwise (dropping rate 3ml/min) to the stirred urea solution by back-dropping until all precipitates were formed; then the precipitates were washed with deionized water and absolute ethanol in turn; white Precipitate precursor, the white precipitate precursor is dried;

Add 0.12g of 0.6um YAG seed crystal and 0.03g of dispersant (polyethylene glycol) to the above-mentioned precipitate precursor, and adjust to rheological state with oxalic acid;

The above rheological phase material was kept at 100°C for 6 hours to obtain a dried product;

Then add flux (1.20g barium fluoride) to the dried product for mixing; then bake at 1600°C for 30 hours in a reducing atmosphere (nitrogen-hydrogen mixed gas) to obtain a roasted product;

Then, the obtained calcined product is subjected to jet crushing, pickling, alkali washing, water washing to remove impurities, drying and sedimentation classification in sequence to obtain a YAG:Ce phosphor with a particle size of about 20 um.

Example 5

The preparation molecule is Y ₃ Al ₅ O ₁₂ : Ce rare earth doped yttrium aluminum garnet phosphor, which is prepared as follows:

Weigh 3.331gY ₂ O ₃ (5N) and 0.086gCeO ₂ (5N) into water, heat and dissolve it with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.08mol/l and a pH of 7. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Take by weighing 2.724g ammoniacal liquor, be mixed with the precipitant solution that concentration is 1.5mol/l;

At room temperature, the mother salt solution was added dropwise (drop rate 6ml/min) to the stirred ammonia solution by back-dropping until all precipitates were formed; then the precipitates were washed with deionized water and absolute ethanol in turn; white Precipitate precursor, the white precipitate precursor is dried;

Add 0.12g of 0.6um YAG seed crystal and 0.01g of dispersant (hydroxycellulose) to the above-mentioned precipitate precursor, and adjust to the rheological state with ethanol;

The above rheological phase material was kept at 100°C for 6 hours to obtain a dried product;

Then add flux (0.06g ammonium fluoride) to the dried product for mixing; then bake at 1500°C for 15 hours in a reducing atmosphere (nitrogen-hydrogen mixture) to obtain a roasted product;

Then, the obtained calcined product is subjected to jet crushing, acid washing, alkali washing, water washing to remove impurities, drying, sedimentation classification, etc., to obtain YAG:Ce phosphor with a particle size of about 10 um.

Example 6

The preparation molecule is Y ₃ Al ₅ O ₁₂ : Ce rare earth doped yttrium aluminum garnet phosphor, which is prepared as follows:

Weigh 3.331gY ₂ O ₃ (5N) and 0.086gCeO ₂ (5N) into water, heat and dissolve it with concentrated nitric acid with a volume ratio of 1ml:1ml, and prepare yttrium cerium with a concentration of 0.08mol/l and a pH of 7. Nitrate mixed solution; then add 18.756g Al(NO ₃ ) ₃ 9H ₂ O to this mixed solution to make metal ion mixed solution (mother salt solution);

Take by weighing 20.171g oxalic acid, be mixed with the precipitant solution that concentration is 2.0mol/;

At room temperature, the mother salt solution was added dropwise (dropping rate 10ml/min) to the stirred oxalic acid solution by back-dropping until all precipitates were formed; then the precipitates were washed with deionized water and absolute ethanol in turn; white Precipitate precursor, the white precipitate precursor is dried;

Add 0.20g of 0.1um YAG seed crystal and 0.01g of dispersant (hydroxycellulose) to the above-mentioned precipitate precursor, and adjust to the rheological state with oxalic acid;

The above rheological phase material was kept at 100°C for 6 hours to obtain a dried product;

Then add flux (0.80g sodium carbonate) to the dried product for mixed grinding; then bake at 1600°C for 5 hours in a reducing atmosphere (nitrogen-hydrogen mixed gas) to obtain a roasted product;

Then, the obtained calcined product is subjected to jet crushing, pickling, alkali washing, water washing to remove impurities, drying and sedimentation classification in sequence to obtain YAG:Ce phosphor with a particle size of about 5.0 um.

The rare earth-doped yttrium aluminum garnet fluorescent powder prepared by the method of the invention has regular shape, uniform particle size, particle size (d ₅₀ ) of 0.1-20 μ, uniform particle size distribution, stable chemical properties, good luminescence performance, and can be effectively excited by blue light ; Can be applied to blue LED chips.

Claims (5)

1. the co-precipitation of a rare earth doping yttrium aluminium garnet fluorescent powder-rheology phase preparation method, it is with the nanometer of regular shape or micron YAG, SiO ₂Or SiC is equipped with rare earth doping yttrium aluminium garnet fluorescent powder as crystal seed with co-precipitation-rheology phase legal system; Preparation process is following:

1) preparation rare earth doping yttrium aluminium garnet fluorescent powder presoma:

1.1) preparing metal ion mixed solution:

Taking by weighing purity by stoichiometric ratio is that the MOX powder of 4N-7N adds in the entry; Preparing metal oxide compound suspension liquid; Add concentrated nitric acid again; Be heated to the MOX powder and dissolve fully, being mixed with concentration is the mixing solutions of the pH value 6-7 of 0.02～0.15mol/l, adds Al (NO by stoichiometric ratio to this mixing solutions again ₃) ₃, make the metals ion mixed solution; Described MOX powder is the mixed powder of yttrium oxide powder and cerium oxide powder;

1.2) compound concentration is the precipitant solution of 1.0～3.0mol/l, said precipitation agent is at least a in ammonium bicarbonate soln, urea, ammoniacal liquor and the oxalic acid solution;

1.3) preparation precipitation by metallic ion thing:

With step 1.1) the metals ion mixed solution is added to step 1.2 with the speed of 1ml/min～10ml/min) in the precipitant solution that makes, carry out precipitin reaction, still aging throw out;

In the said metals ion mixed solution in metals ion total moles and the said precipitant solution mole number proportioning of precipitation agent be 1: 20;

1.4) use deionized water and absolute ethanol washing gained throw out more successively, get white rare earth doping yttrium aluminium garnet fluorescent powder presoma, and said rare earth doping yttrium aluminium garnet fluorescent powder presoma is carried out drying treatment;

2) with crystal seed and step 1.4) the rare earth doping yttrium aluminium garnet fluorescent powder presoma mix, in this mixture, add dispersion agent again, and and solvent, said mixture is adjusted to the rheology phase, and this rheology phase mixture is carried out drying treatment;

Described crystal seed is YAG crystal seed, SiO ₂Crystal seed or SiC crystal seed;

Said dispersion agent is an ammonium sulfate, at least a in polyoxyethylene glycol, hydroxylated cellulose and the Trimethyllaurylammonium bromide;

Said solvent is deionized water, ethanol, acetate or oxalic acid;

Said crystal seed, said dispersion agent and Y ₃Al ₅O ₁₂: the weight part proportioning of Ce fluorescent material presoma is 0.1～5: 0.1～0.5: 100;

3) in step 2) the rheology phase mixture after drying treatment in add the fusing assistant of the 1-20wt% of this rheology phase mixture gross weight; Evenly form compound through ground and mixed; In reducing atmosphere, said compound is carried out roasting and get product of roasting, said maturing temperature is 900 ℃～1600 ℃;

Described fusing assistant is an alkali metal halide, alkaline earth metal halide, boric acid, at least a in ammonium halogenide, alkaline carbonate and the alkaline earth metal carbonate;

4) product of roasting that step 3) is obtained washs successively again, removal of impurities, oven dry and classification, makes rare earth doping yttrium aluminium garnet fluorescent powder.

2. by the co-precipitation-rheology phase preparation method of the described rare earth doping yttrium aluminium garnet fluorescent powder of claim 1, it is characterized in that the grinding in the said step 3) is for to grind in ethanol, acetone or water.

3. by the co-precipitation-rheology phase preparation method of the described rare earth doping yttrium aluminium garnet fluorescent powder of claim 3, it is characterized in that the roasting time of described step 4) is 2～30 hours.

4. by the co-precipitation-rheology phase preparation method of the described rare earth doping yttrium aluminium garnet fluorescent powder of claim 1, it is characterized in that the removal of impurities of in the said step 4) said product of roasting being carried out is to its pickling, alkali cleaning or washing.

5. press the co-precipitation-rheology phase preparation method of the described rare earth doping yttrium aluminium garnet fluorescent powder of claim 1,

It is characterized in that, be classified as a kind of classification or several kinds of mixing-classifyings in settling process classification, method of sieving classification, hydraulic elutria-tion method classification and the classification of air classification method to what said product of roasting carried out in the said step 4).