CN1212367C - Red RE oxide luminophor and its prepn - Google Patents

Abstract

The invention belongs to the field of luminescent materials, and relates to a fluorescent powder that emits red fluorescence under the excitation of electron beams or vacuum ultraviolet rays, and is a rare earth oxide red fluorescent powder and a manufacturing method thereof. The phosphor powder involved in the present invention has a chemical expression: (Y _1-xy Gd _x Eu _y ) ₂ O ₃ , where 0<x≤0.9, 0.01≤y≤0.1. In the present invention, by introducing Gd ions into the cubic Y ₂ O ₃ :Eu ³⁺ system, a solid solid of (Y, Gd) ₂ O ₃ and (Y, Gd, Eu) ₂ O ₃ with a cubic structure is formed at a high temperature of 1250°C. melt. This solid solution becomes a rare earth oxide red phosphor after material selection, mixing, sintering and post-treatment. The characteristics of the present invention are: (1) the fluorescent powder still has a cubic structure above 1250°C, and the crystal quality is good; (2) there is a satisfactory concentration range of the activator; (3) the use of additives reduces the burning temperature and improves the luminous brightness , to promote crystal growth; (4) The manufacturing process is simple and easy to operate.

Description

Rare earth oxide red phosphor and preparation method thereof

Technical field: the invention belongs to the field of luminescent materials, and relates to a phosphor emitting red fluorescence under excitation of electron beams or vacuum ultraviolet rays, which is a rare earth oxide red phosphor and a manufacturing method thereof.

Background technology: There are many materials that can emit light under excitation, and these materials can be used as phosphors in display and other fields, such as cubic Gd ₂ O ₃ . Usually, the phase transition temperature of cubic Gd ₂ O ₃ into monoclinic is about 1250°C, that is, the Gd ₂ O ₃ obtained above 1250°C is a monoclinic structure. According to this property of cubic Gd ₂ O ₃ , fluorescent powder with cubic Gd ₂ O ₃ as the matrix can be prepared. However, phosphors prepared with cubic Gd ₂ O ₃ as a matrix have a monoclinic structure, and phosphors with a monoclinic structure have low luminous efficiency. Cubic yttrium oxide activated by Eu ³⁺ emits red light under electron beam or vacuum ultraviolet excitation, and is widely used in new technologies such as display, imaging, and lighting sources. However, with the development of these technologies, Y ₂ O ₃ : The luminescent properties of Eu ³⁺ can no longer meet the needs, and people demand to provide luminescent materials with better properties.

Summary of the invention: In the present invention, Gd ions are introduced into the cubic Y ₂ O ₃ :Eu ³⁺ system to partially replace Y, and Y ₂ O ₃ and Gd ₂ O ₃ and Y ₂ O ₃ , Gd ₂ O ₃ and Eu ₂ O ₃ form a solid solution of (Y, Gd) ₂ O ₃ and (Y, Gd, Eu) ₂ O ₃ with a cubic structure. This new solid solution is a very stable homogeneous replacement solid solution with good luminescent properties. By introducing Gd ions into the cubic Y ₂ O ₃ :Eu ³⁺ system, the purpose is to provide a rare earth oxide red phosphor with high luminous brightness and excellent color purity and a method for preparing the phosphor

In the present invention, by introducing Gd ions into the cubic Y ₂ O ₃ :Eu ³⁺ system to partially replace Y, Y ₂ O ₃ and Gd ₂ O ₃ and Y ₂ O ₃ , Gd ₂ O ₃ and Eu ₂ O ₃ forms a solid solution of (Y, Gd) ₂ O ₃ and (Y, Gd, Eu) ₂ O ₃ with a cubic structure to obtain a rare earth oxide red phosphor.

After the present invention introduces Gd ions into the cubic Y ₂ O ₃ :Eu ³⁺ system, Y ₂ O ₃ and Gd ₂ O ₃ and Y ₂ O ₃ , Gd ₂ O ₃ and Eu ₂ O ₃ in the system form a cubic structure (Y, Gd) ₂ O ₃ and (Y, Gd, Eu) ₂ O ₃ solid solution, its chemical expression is as follows:

(Y _1-xy Gd _x Eu _y ) ₂ O ₃

Wherein, x is the content of the matrix component Gd, and the content is 0<x≤0.9, and y is the content of the activator Eu, and the content is 0.01≤y≤0.1. The phosphor matrix part is composed of oxides of Gd and Y, and the activator material is an oxide containing Eu ³⁺ .

In the rare earth oxide red phosphor powder of the present invention, when the content of the matrix component Gd is in the range of 0<x≤0.9, when the phase transition temperature (1250° C.) is higher than Gd ₂ O ₃ , (Y _1-xy Gd _x Eu _y ) ₂ O ₃ phosphor is still a body-centered cubic structure, which has the characteristics of high luminous brightness and excellent color purity.

The present invention _{forms ( Y , Gd ) 2} O ₃ and _{( Y , Gd} , Eu) ₂ O ₃ solid solution is a very stable homogeneous solid solution with good luminescent properties.

The preparation process steps of the rare earth oxide red fluorescent powder of the present invention are as follows:

1. Material selection

Weigh a certain amount of Y 2 O ₃ , Gd ₂ O ₃ , Eu _{2 O 3 with a purity of 99.99% according to the stoichiometric ratio of (Y 1-xy Gd x Eu y ) 2 O 3 and boric acid and metal} fluorides with analytical purity above and one or more of metal carbonates. Wherein, boric acid, metal fluoride and metal carbonate are additives, the metal fluoride can be CaF ₂ , and the metal carbonate can be K ₂ CO ₃ or Li ₂ CO ₃ . The addition amount of the additive is 0.1-0.5 wt%.

2. Mixing

_{One or one or three _ _ _ _ _ _ _ _} A kind of agate is used as a raw material, put into a ball mill jar, put into agate balls, the weight ratio of the balls to the raw materials is 1:1, and the ball milling time is more than 10 hours.

3. Sintering

The above-mentioned raw materials mixed by ball milling are put into an alumina crucible or a corundum crucible, covered and put into a high-temperature sintering furnace. The raw materials were at room temperature when loaded into alumina crucibles. The raw materials in the alumina crucible are raised to 1250-1400°C with the furnace, kept at a constant temperature for 1-2 hours, stop heating, and taken out with the furnace lowered to below 1000°C.

4. Post-processing

The above raw materials are calcined to obtain a white powder product. The obtained product white powder is crushed, put into a ball mill jar, add water and φ3mm glass balls, wherein the ratio of product white powder powder, water and glass balls is: powder: water: ball ≈ 1: 1: 1, ball mill 2 to 4 hours. The ball-milled powder and water form a slurry, which is put into a beaker, stirred with 2% HCl solution for 2-4 hours, and then washed with hot deionized water at 70-80°C until neutral. Sieve through 400 meshes, filter with suction and dry in an oven at 110-130°C to obtain fluorescent powder. The dried fluorescent powder is then sieved through a 260-mesh sieve and tested to obtain the red fluorescent powder of the present invention.

The characteristics of the present invention are: (1) Obtain cubic structure (Y _1-xy Gd _x Eu _y ) ₂ O ₃ fluorescent powder at a high temperature above 1250°C, even when the Gd content is as high as 90%, that is (Y _0.06 Gd _0.90 Eu _0.04 ) ₂ O ₃ , the material still has a cubic structure, and there is no monoclinic Gd ₂ O ₃ impurity phase. Figure 1 shows the XRD pattern (2θ=18°～74°) of (Y _0.06 Gd _0.90 Eu _0.04 ) ₂ O ₃ phosphor, which is a typical body-centered cubic structure with strong diffraction peaks and full width at half width (FWHM ) is narrow, and the crystal quality is good; (2) The emission spectrum of the obtained high-temperature cubic (Y, Gd) ₂ O ₃ :Eu phosphor is exactly the same as that of cubic Y ₂ O ₃ :Eu and cubic Gd ₂ O ₃ :Eu, As shown in Figure 2; (3) there is a satisfactory activator concentration range, as shown in Figure 3, the optimal concentration is 0.04mol; (4) select a small amount of boric acid, metal fluoride and metal carbonate as additives, not only reduce The burning temperature is lowered, the luminous brightness is improved, and crystal growth is promoted; (5) The manufacturing process is simple, easy to operate, and suitable for mass production.

Description of drawings:

Figure 1 is the XRD pattern (2θ=18°～74°) of (Y _0.06 Gd _0.90 Eu _0.04 ) ₂ O ₃ phosphor powder;

Fig. 2 is the emission spectrum diagram of cubic (Y, Gd) ₂ O ₃ :Eu, Y ₂ O ₃ :Eu, Gd ₂ O ₃ :Eu phosphors;

Fig. 3 is a graph showing the relationship between the luminous intensity of phosphor powder and the concentration of activator Eu ³⁺ .

Detailed ways:

Example 1. Weigh Y ₂ O ₃ 100g, Eu ₂ O ₃ 7g, BaF ₂ 0.1g, H ₃ BO ₃ 0.3g, put the above raw materials into a ball mill jar, put in agate balls, the weight ratio of balls to raw materials The ratio is 1:1, and the ball milling time is more than 10 hours. Put the mixed material into the corundum crucible and put it into a high-temperature sintering furnace. Raise the temperature of the sintering furnace to 1270°C and keep the temperature constant for 2 hours. After the furnace temperature drops below 1000°C, take out the crucible and cool it to room temperature. Crush the materials out of the furnace, put them into a ball mill jar, add water and φ3mm glass balls, powder: water: balls ≈ 1:1:1, and ball mill at a slow speed for 2 hours. Put the slurry into a beaker, stir with 2-5% HCl solution for 2 hours, then wash with hot deionized water at 70-80°C until neutral, sieve through 400 mesh, filter with suction and dry in an oven at 120°C. The dried fluorescent powder was sieved through a 260-mesh sieve to obtain (Y _1-xy Gd _x Eu _y ) ₂ O ₃ red phosphor after detection, and the relative luminous intensity was 100 under cathode ray excitation.

Example 2. Weigh 80g of Y ₂ O ₃ , 24g of Gd ₂ O ₃ , 6g of Eu ₂ O ₃ , 0.1g of BaF ₂ , 0.3g of H ₃ BO ₃ . Strength is 98.

Example 3. Weigh 70g of Y ₂ O ₃ , 22g of Gd ₂ O ₃ , 13g of Eu ₂ O ₃ , 0.1g of BaF ₂ , and 0.3g of H ₃ BO ₃ , and the other conditions are the same as in Example 1. Relatively luminesce under cathode ray excitation Strength was 87.2.

Example 4. Weigh Y ₂ O ₃ 60g, Gd ₂ O ₃ 44g, Eu ₂ O ₃ 6g, BaF ₂ 0.1g, H ₃ BO ₃ 0.3g, and other conditions are the same as in Example 1, under the excitation of cathode ray The luminous intensity was 102.4.

Example 5. Weigh 50g of Y ₂ O ₃ , 39.5g of Gd ₂ O ₃ , 11.5g of Eu ₂ O ₃ , 0.1g of BaF ₂ , 0.3g of H ₃ BO ₃ , and the other conditions are the same as in Example 1, under the excitation of cathode ray The relative luminous intensity was 91.6.

Example 6. Weigh 40g of Y ₂ O ₃ , 57g of Gd ₂ O ₃ , 5g of Eu ₂ O ₃ , 0.1g of BaF ₂ , 0.3g of H ₃ BO ₃ , and the rest of the conditions are the same as in Example 1. The luminous intensity was 101.6.

Example 7. Weigh 40g of Y ₂ O ₃ , 63g of Gd ₂ O ₃ , 12g of Eu ₂ O ₃ , 0.35g of BaF ₂ , 0.6g of H ₃ BO ₃ . Strength is 89.8.

Example 8. Weigh Y ₂ O ₃ 20g, Gd ₂ O ₃ 86g, Eu ₂ O ₃ 5g, BaF ₂ 0.1g, H ₃ BO ₃ 0.3g, and other conditions are the same as in Example 1. Relatively luminesce under cathode ray excitation Strength was 97.3.

Example 9. Weigh 20g of Y ₂ O ₃ , 107g of Gd ₂ O ₃ , 13g of Eu ₂ O ₃ , _0.4g of BaF 2 , and 0.7g of H ₃ BO ₃ . Strength is 86.5.

Example 10. Weigh 70g of Y ₂ O ₃ , 30g of Gd ₂ O ₃ , 6g of Eu ₂ O ₃ , 0.1g of BaF ₂ , and 0.3g of H ₃ BO ₃ , and the rest of the conditions are the same as in Example 1. Relatively luminesce under cathode ray excitation Strength is 103.1.

Claims (7)

1. A rare earth oxide red phosphor, characterized in that Gd ions are introduced into the cubic Y ₂ O ₃ :Eu ³⁺ system to partially replace Y, and Y ₂ O ₃ and Gd ₂ O ₃ and Y ₂ O ₃ , Gd ₂ O ₃ and Eu ₂ O ₃ form a solid solution of (Y, Gd) ₂ O ₃ and (Y, Gd, Eu) ₂ O ₃ with a cubic structure, and its chemical expression is: (Y _1-xy Gd _x Eu _y ) ₂ O ₃ , where x is the content of matrix component Gd, the value is 0<x≤0.9, y is the content of activator Eu, the value is 0.01≤y≤0.1, solid solution The body also contains additives. 2. The rare earth oxide red phosphor according to claim 1, characterized in that the contained additives are one or more of boric acid, metal fluoride, and metal carbonate. 3. The rare earth oxide red phosphor according to claim 2, characterized in that the additive metal fluoride is CaF ₂ , and the metal carbonate is K ₂ CO ₃ or Li ₂ CO ₃ . 4. The rare earth oxide red phosphor according to claim 3, characterized in that the amount of additive added is 0.1-0.5 wt%. 5. The preparation method of the rare earth oxide red phosphor according to claim 1, comprising the processes of material selection, material mixing, sintering and post-treatment, characterized in that according to (Y _1-xy Gd _x Eu _y ) ₂ O ₃ Stoichiometric ratio Weigh a certain amount _of Y _{2 O 3} , Gd _{2 O 3} , Eu ₂ O ₃ with a purity _of 99.99% _and additives with analytical purity above _; And the additives are put into the ball mill tank, put agate balls, ball mill and mix the materials; put the raw materials after the ball mill and mix into the alumina crucible or corundum crucible, put the cover into the high temperature sintering furnace for sintering; the white powder obtained by sintering Break the product, put it into a ball mill jar, add water and φ3mm glass balls, the powder after ball milling and water will become a slurry, put the slurry into a beaker, stir with 2% HCl solution for 2-4 hours, and then use 70- Wash with hot deionized water at 80°C until neutral, pass through a 400-mesh sieve, filter with suction, and dry in an oven at 110-130°C to obtain phosphor. 6. The preparation method of rare earth oxide red fluorescent powder according to claim 5, characterized in that the weight ratio of the agate balls used for mixing the materials to the raw materials is 1:1, and the ball milling time is more than 10 hours; Put it into an alumina crucible, raise it to 1250-1400°C with the furnace, keep the temperature constant for 1-2 hours, stop the temperature rise, and take it out with the furnace down to below 1000°C; white powder product in post-treatment: water: glass ball ≈ 1:1:1 . 7. The preparation method of rare earth oxide red phosphor according to claim 5, characterized in that the dried phosphor is sieved through a 260-mesh sieve.

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