TWI415817B - Method of fabricating yttrium aluminum garnet with adjustable sizes - Google Patents

Abstract

A method of fabricating yttrium aluminum garnet (YAG) with adjustable sizes is disclosed, which comprises: (A) providing aluminum oxide powder and yttrium oxide powder; (B) mixing the aluminum oxide powder and the yttrium oxide powder; and (C) heat treating the mixed powder of aluminum oxide and yttrium oxide to obtain yttrium aluminum garnet powder; wherein, when the diameter of the yttrium aluminum garnet is defined as a, and the diameter of the yttrium oxide is defined as b, a and b satisfies formula 1: [formula 1] a/b=1.2 to 1.5. The method of fabricating yttrium aluminum garnet of the present invention is provided based on solid state reaction using powders of aluminum and yttrium oxides as raw materials. The method of fabricating YAG of the present invention has the advantages of being easily for large quantity manufacturing, high fabricating safety, low providing cost, etc.

Description

Method for preparing yttrium aluminum garnet powder with adjustable particle size

The invention relates to a method for preparing a YAG (yttrium aluminum garnet) powder, in particular to a preparation method for a yttrium aluminum garnet powder with adjustable particle size.

Lighting is an indispensable item in people's daily lives today. It is the necessary mission of today's lighting engineering workers to develop energy-saving lighting equipment under the requirement of energy conservation. The white LED is a product that meets this requirement, and has the advantages of small volume, low heat generation, low power consumption, long life, fast reaction speed, environmental protection, flat packaging, and easy development into a light and thin short product.

Among them, one of the most popular products is white LED, which is a white color produced by mixing blue and yellow colors with blue light to excite yellow fluorescent powder. The main material of this yellow phosphor powder is yttrium aluminum garnet powder (YAG: Ce). The luminescence intensity of the yttrium aluminum garnet powder is related to the integrity and particle size of the powder shape. Therefore, the production of a yttrium aluminum garnet powder having a predetermined uniform particle size has a substantial effect on the improvement of its function.

Among the conventional techniques, pure phase yttrium aluminum garnet (YAG, Y ₃ Al ₅ O ₁₂ ) powder can be obtained by solid state reaction or more sophisticated chemical methods. The latter includes the use of a precipitation method, a sol-gel method, a hydrothermal method, and a combustion method, etc., in order to make a finer unit of the cerium oxide and the alumina raw material components to be used, thereby achieving more uniform mixing (solid reaction method is difficult to achieve). To reduce the synthesis temperature and speed up the synthesis. Solid state reactions are usually synthesized at higher temperatures (eg, temperatures above 1600 ° C). The reaction time is also longer, or a step of repeated heat treatment/grinding dispersion is required to obtain a single-phase yttrium aluminum garnet. In either case, it is impossible to simultaneously produce a yttrium aluminum garnet powder having a specific particle size and a uniform particle size distribution in the synthesis process. Therefore, basically, the synthesized yttrium aluminum garnet powder must be subjected to secondary particle size reprocessing (for example, particle grinding, high temperature curing, sieving, etc.) to obtain a desired particle size and a uniform particle size distribution range. Yttrium aluminum garnet powder.

Therefore, there is a need in the art for a method for preparing a yttrium aluminum garnet powder, which eliminates the reprocessing steps such as particle grinding and sieving as described above, so that a bismuth aluminum having a specific particle size and a uniform particle size distribution can be synthesized at one time. Garnet powder.

The main object of the present invention is to provide a method for preparing a YAG (yttrium aluminum garnet) powder with adjustable particle size, which can rapidly synthesize a single phase yttrium aluminum garnet with a specific particle diameter by solid state thermal reaction method. Powder, and has the advantages of easy mass production, high safety and low cost.

In order to achieve the above object, the present invention provides a method for preparing a particle size-adjustable yttrium aluminum garnet powder, comprising: (A) providing an alumina powder and a cerium oxide powder; (B) the cerium oxide and aluminum oxide Powder mixing; and (C) heat-treating the mixed cerium oxide and aluminum oxide powder to obtain a yttrium aluminum garnet powder; wherein, when the yttrium aluminum garnet powder has a particle diameter of a, and the particle size of the cerium oxide powder When it is b, it is in accordance with Equation 1:

[Formula 1]

a/b = 1.2 to 1.5.

The preparation method of the particle size adjustable yttrium aluminum garnet powder of the invention can rapidly synthesize a single phase yttrium aluminum garnet powder with a specific particle size. It uses yttria (Y ₂ O ₃ ) and alumina (α-Al ₂ O ₃ ) powder as raw materials. However, the particle size of the cerium oxide powder needs to be similar to the particle size of the yttrium aluminum garnet powder to be produced. After the alumina is mixed with the cerium oxide, it is directly placed at a temperature of about 1000 to 1550 ° C for about 1 to 30 minutes, that is, a single phase of the yttrium aluminum garnet (Y ₃ Al ₅ O ₁₂ ) can be obtained by one heat treatment. powder. The particle size of the yttrium aluminum garnet powder formed at this time is about 24% larger than the diameter of the yttria (Y ₂ O ₃ ) powder of the raw material. The present invention utilizes this phenomenon to synthesize a yttrium aluminum garnet (YAG, Y ₃ Al ₅ O ₁₂ ) powder having a specific particle diameter and a pure phase. The invention is characterized in that it is easy to synthesize a yttrium aluminum garnet powder of a specific particle size by a simple method, can be mass-produced, is free from the steps of performing multiple grinding and reheating in the synthesis process, and is difficult to control the particle size, and is free of particle size. The processing operation has the advantages of high safety, easy mass production, and effective cost reduction.

When yttrium aluminum garnet is synthesized from bismuth and aluminum oxide powder, it has been confirmed that the aluminum component will enter the yttrium oxide structure to form yttrium aluminum garnet. The present invention utilizes this phenomenon to rapidly synthesize yttrium aluminum garnet by uniformly mixing the yttrium oxide and alumina powder based on the particle size of the cerium oxide raw material powder and using an alumina powder of a suitable particle size range. Thus, a yttrium aluminum garnet powder having a particle size slightly larger than that of the raw material yttrium oxide can be obtained.

In addition, the particle size of the mixed yttria (Y ₂ O ₃ ) and alumina (α-Al ₂ O ₃ ) powders should be appropriately proportioned, on the one hand, the two granules can be completely contacted and the two components of the granules can be added. The contact point, on the other hand, reduces the distance required for aluminum diffusion, allowing the mixed powder system to quickly achieve the formation of yttrium aluminum garnet via a surface reaction mechanism.

In the preparation method of the particle size adjustable yttrium aluminum garnet powder of the present invention, the formula 1 may preferably be: a/b = 1.2 to 1.4.

In the preparation method of the particle size adjustable yttrium aluminum garnet powder of the present invention, the temperature of the heat treatment in the step (C) is preferably from 1000 ° C to 1550 ° C, more preferably from 1200 ° C to 1550 ° C: The heat treatment time is preferably from 1 minute to 5 hours. The heat treatment time should be adjusted according to the particle size of yttria and alumina powder.

In the preparation method of the particle size adjustable yttrium aluminum garnet powder of the present invention, the particle diameter of the cerium oxide powder may preferably be between 1 nm and 10 μm; more preferably between 1 nm and 5 μm; more preferably It can be between 1 nm and 1 μm.

Further, in the preparation method of the particle size-adjustable yttrium aluminum garnet powder of the present invention, the particle size of the cerium oxide and the aluminum oxide powder may preferably be [alumina/yttria] = 0.5 to 5.

In the preparation method of the particle size adjustable yttrium aluminum garnet powder of the present invention, before the step (C), it is preferred to further comprise a step (C0): preheating the mixed cerium oxide and aluminum oxide powder, and The preheating temperature is preferably from 600 ° C to 800 ° C, and the preheating time is preferably from 1 second to 1 minute.

In the preparation method of the particle size adjustable yttrium aluminum garnet powder of the present invention, after the step (B), it is preferred to further comprise a step (B1): dry-forming the mixed cerium oxide and aluminum oxide powder.

The invention relates to an improved solid state reaction method, which can directly realize the synthesis of a pure phase yttrium aluminum garnet powder of a predetermined particle diameter at one time, and can be applied to a large amount of produce. The preparation method of the yttrium aluminum garnet powder of the invention can eliminate the trouble of holding the temperature at 1600 ° C for a long time in the traditional synthesis process, and performing multiple re-grinding/heat treatment, and can eliminate the traditional technology in order to obtain a specific particle size 钇 aluminum pomegranate The stone powder needs to undergo high-temperature ripening energy-consuming and time-consuming steps. Therefore, the preparation method of the yttrium aluminum garnet powder of the invention has the advantages of easy mass production, reduced process steps, low energy consumption, effective cost reduction, high safety and the like.

The embodiments of the present invention are described by way of specific examples, and those skilled in the art can readily appreciate the other advantages and advantages of the present invention. The following specific examples are merely illustrative, and are not intended to limit the remainder of the disclosure in any way. The omission, modification, derogation, and alteration of the form and details of the present invention can be carried out by those skilled in the art without departing from the spirit and scope of the invention.

[Example 1]

In the present embodiment, the predetermined particle diameter of the target powder (yttrium aluminum garnet powder) is set to be slightly larger than 100 nm (here, the calculated particle diameter is assumed to be 125 nm). The preparation conditions are as follows.

a. Powder particle size: yttrium oxide is 100 nm (analytical particle size 113.82 nm) (possible diffusion distance), alumina is 200 nm (analytical particle size 230.00 nm); b. alumina/yttria particle size ratio is 2.0; By calculation, a 200 nm alumina surface area is large enough to cover about 26 100 nm oxidized mitochondria. When the yttrium aluminum garnet is formed, the stoichiometry of the two components of alumina and cerium oxide is 1 to 8, which means that when 200 nm alumina powder is mixed with 100 nm cerium oxide powder, the two can be completely contacted with each other.

First, (A) the above cerium oxide and aluminum oxide powder are taken, (B) the cerium oxide and the aluminum oxide powder are uniformly mixed, and (B1) is subjected to dry pressing (density of about 0.91 g/cm ³ ), (C0) The sample is preheated at 700 ° C for 10 seconds, and then (C) is directly placed at 1050-1200 ° C for 5 - 120 seconds, so that a yttrium aluminum garnet powder having a particle diameter of about 100 nm can be obtained.

In the present embodiment, the detection of the properties of the raw material and the synthetic powder is detailed as follows: The particle size distribution of the powder is measured by a laser particle size distribution meter (Malvern Zetasizer 1000). The thermal reaction behavior of the synthesis process was analyzed by a thermal differential analyzer (Setaram TGA 92). The heating rate was 10 ° C / min, and the measurement was carried out in an air atmosphere. The crystal phase in the synthetic powder was identified using an X-ray diffractometer (Rigaku MiniFlex, CuKα): YAM (Y ₄ Al ₂ O ₉ ), YAP (YAlO ₃ ), and YAG (Y ₃ Al ₅ O ₁₂ ) and their contents. . The latter measurement was quantified using the internal standard method. The diffraction surface used is YAG (420), YAM ( 2i), and YAP (121). The reference internal standard is CaF ₂ (111).

Fig. 1(a) is an SEM image of the original morphology of the raw material after mixing the raw material powder of the present embodiment; Fig. 1(b) is an SEM image of the yttrium aluminum garnet after heat treatment at 30%; Fig. 1(c) is a heat treatment The SEM image when the amount of yttrium aluminum garnet is 60%; and Fig. 1(d) is the SEM image when the amount of yttrium aluminum garnet is 90% after heat treatment. It is apparent from Fig. 1(a) to (d) that in addition to the decrease of 200 nm alumina granules, other granules, including the formed yttrium aluminum garnet granules (analytical particle size 154.12 nm), appearance No significant changes have taken place.

[Embodiment 2]

In the present embodiment, the predetermined particle diameter of the target powder (yttrium aluminum garnet powder) was set to 400 nm. The preparation conditions are as follows.

a. Powder particle size: yttrium oxide is 300 nm (analytical particle size 319.27 nm)), alumina is 400 nm (analytical particle size 391.54 nm);

b. The alumina/yttria particle size ratio is 1.33;

c. Calculated, because a 400 nm alumina surface area can cover about 16 300 nm oxidized mitochondria (or a 300 nm yttrium oxide surface area can cover about 18 200 nm oxidation) Aluminum granules). The alumina and yttrium oxide yttrium yttrium oxides have a stoichiometry of 1 to 2.4, which means that when 400 nm alumina powder is mixed with 300 nm cerium oxide powder, the two can completely get each other. contact.

First, (A) the above cerium oxide and aluminum oxide powder are taken, (B) the cerium oxide and the aluminum oxide powder are uniformly mixed, and (B1) is subjected to dry pressing (density of about 0.91 g/cm ³ ), (C0) The sample is preheated at 700 ° C for 10 seconds, and then (C) is directly placed at 1350-1450 ° C for 5 - 120 seconds, so that a yttrium aluminum garnet powder having a particle diameter of about 400 nm can be obtained.

In the present embodiment, the detection of the properties of the raw material and the synthetic powder is the same as that used in the first embodiment, and therefore will not be described herein.

Fig. 2(a) is an SEM image of the original morphology of the raw material after mixing the raw material powder of the present embodiment; Fig. 2(b) is an SEM image of the yttrium aluminum garnet after the heat treatment is 30%; Fig. 2(c) is the heat treatment The SEM image when the amount of yttrium aluminum garnet is 60%; and Fig. 2(d) is the SEM image when the amount of yttrium aluminum garnet is 90% after heat treatment. It is apparent from Fig. 2(a) to (d) that except for the decrease of 400 nm alumina granules, the other granules, including the formed yttrium aluminum garnet granules, did not change significantly, but eventually The particle size of the obtained yttrium aluminum garnet is close to 400 nm (analytical particle size 422.82 nm).

[Example 3]

In the present embodiment, the predetermined particle diameter of the target powder (yttrium aluminum garnet powder) was set to 500 nm. The preparation conditions are as follows.

a. Powder particle size: yttrium oxide is 400 nm (analytical particle size 391.54 nm)), alumina is 200 nm (analytical particle size 230.00 nm);

b. The alumina/yttria particle size ratio is 0.5;

c. Calculated, due to a 400 nm yttrium oxide surface area can cover about 26 200 nm oxidized mitochondria. The stoichiometry of alumina and yttrium oxide when yttrium aluminum garnet is formed by alumina and yttrium oxide is 8 to 1, which means that when 200 nm alumina powder is mixed with 400 nm yttrium oxide powder, the two can be completely obtained. Contact each other.

First, (A) the above-mentioned cerium oxide having a particle diameter of 400 nm and an alumina powder having a particle diameter of 200 nm, (B) uniformly mixing the cerium oxide and the aluminum oxide two-component powder, and (B1) after dry pressing ( The density is about 0.91 g/cm ³ ), and the (C0) sample is preheated at 700 ° C for 10 seconds, and then (C) is directly placed at 1450-1500 ° C for 5-18 80 seconds, so that a crucible having a particle diameter of about 500 nm can be obtained. Aluminum garnet powder.

In the present embodiment, the detection of the properties of the raw material and the synthetic powder is the same as that used in the first embodiment, and therefore will not be described herein.

Fig. 3(a) is an SEM image of the original appearance of the raw material powder after mixing the raw material powder of the present embodiment; Fig. 3(b) is an SEM image of the yttrium aluminum garnet after the heat treatment is 30%; Fig. 3(c) is the heat treatment The SEM image when the amount of yttrium aluminum garnet is 60% is generated: and Fig. 3(d) is the SEM image when the amount of yttrium aluminum garnet is 90% after heat treatment. It is apparent from Fig. 3(a) to (d) that except for the decrease of alumina granules at 200 nm, the granules of the granules containing the yttrium aluminum garnet formed have not changed significantly, and finally The particle size of the obtained yttrium aluminum garnet is close to 500 nm (analytical particle size 491.58 nm).

4 is a graph showing the relationship between the particle size of the yttrium aluminum garnet powder synthesized in Examples 1, 2, and 3 of the present invention and the particle size of the raw material yttrium oxide powder, wherein the dotted line indicates the actual measured value, and the dotted line portion is the theoretical calculation. value. It can be seen from Fig. 4 that the particle size of the cerium oxide powder actually used in the embodiments 1, 2, and 3, and the particle size of the yttrium aluminum garnet powder synthesized therefrom can be nearly perfectly solved by the equation.

a/b=1.24 [Formula 2]

It is indicated that a is the particle size of the synthesized yttrium aluminum garnet powder, and b is the particle size of the raw material cerium oxide powder. This formula 2 also represents a theoretically calculated relationship between the particle size a of the yttrium aluminum garnet powder synthesized and the particle size b of the raw material cerium oxide powder.

The invention is an improved solid state reaction method, which can directly realize the synthesis of pure phase yttrium aluminum garnet powder of a predetermined particle diameter at one time, and can be applied to mass production. The preparation method of the yttrium aluminum garnet powder of the invention can eliminate the trouble of holding the temperature at 1600 ° C for a long time in the traditional synthesis process, and performing multiple re-grinding/heat treatment, and can eliminate the traditional technology in order to obtain a specific particle size 钇 aluminum pomegranate The stone powder needs to undergo high-temperature ripening energy-consuming and time-consuming steps. Therefore, the preparation method of the yttrium aluminum garnet powder of the invention has the advantages of easy mass production, reduced process steps, low energy consumption, effective cost reduction, high safety and the like.

In summary, the method for preparing the particle size adjustable yttrium aluminum garnet powder of the present invention can rapidly synthesize a single phase yttrium aluminum garnet powder having a specific particle diameter, which uses yttrium oxide (Y ₂ O ₃ ) and aluminum oxide ( α-Al ₂ O3) powder is used as a raw material. However, the particle size of the cerium oxide powder should be similar to the particle size of the yttrium aluminum garnet powder to be produced, and after mixing the alumina with the cerium oxide, the temperature is maintained at a temperature of about 1000 to 1550 ° C for about 1 to 30 minutes, that is, the heat treatment can be performed once. A yttrium aluminum garnet (Y ₃ Al ₅ O ₁₂ ) powder having a single phase of a specific particle size is obtained. The particle size of the yttrium aluminum garnet powder formed at this time is about 24% larger than the diameter of the yttria (Y ₂ O ₃ ) powder of the raw material. The present invention utilizes this phenomenon to synthesize a yttrium aluminum garnet (YAG, Y ₃ Al ₅ Ol2) powder having a specific particle diameter and a pure phase. The invention is characterized in that the yttrium aluminum garnet powder of a specific particle size can be easily synthesized by a simple method, can be mass-produced, the steps of performing multiple grinding and re-heat treatment in the synthesis process, and the particle size reprocessing operation, and It has the advantages of high safety, easy mass production, and effective cost reduction.

The above-mentioned embodiments are merely examples for convenience of description, and the scope of the claims is intended to be limited to the above embodiments.

Fig. 1(a) is a SEM image showing the in vitro appearance of raw particles after mixing raw material powders in Example 1 of the present invention.

Fig. 1(b) is a SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 1 of the present invention of 30%.

Fig. 1 (c) is an SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 1 of the present invention of 60%.

Fig. 1(d) is a SEM image showing that the amount of yttrium aluminum garnet formed after heat treatment in Example 1 of the present invention is 90%.

Fig. 2 (a) is a SEM image of the original appearance of the raw particles after mixing the raw material powders in Example 2 of the present invention.

Fig. 2(b) is a SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 2 of the present invention.

Fig. 2 (c) is an SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 2 of the present invention.

Fig. 2 (d) is an SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 2 of the present invention.

Fig. 3 (a) is a SEM image of the original appearance of the raw material after mixing the raw material powders in Example 3 of the present invention.

Fig. 3(b) is a SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 3 of the present invention.

Fig. 3 (c) is an SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 3 of the present invention.

Fig. 3(d) is a SEM image showing the amount of yttrium aluminum garnet formed after heat treatment in Example 3 of the present invention.

Figure 4 is a graph showing the relationship between the particle size of the yttrium aluminum garnet powder and the particle size of the raw material cerium oxide powder in Examples 1, 2, and 3 of the present invention.

Claims (11)

A method for preparing a YAG (yttrium aluminum garnet) powder having an adjustable particle size, comprising: (A) providing an alumina powder and a cerium oxide powder; (B) preparing the cerium oxide and aluminum oxide powder And (C) heat-treating the mixed cerium oxide and aluminum oxide powder to obtain a yttrium aluminum garnet powder; wherein, when the yttrium aluminum garnet powder has a particle diameter of a, and the cerium oxide powder has a particle diameter of In the case of b, it conforms to the formula i: [Formula 1] a/b = 1.2 to 1.5. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 1, wherein the formula 1 is: a/b = 1.2 to 1.4. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 1, wherein the temperature of the heat treatment in the step (C) is from 1000 ° C to 1550 ° C. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 3, wherein the temperature of the heat treatment in the step (C) is 1200 ° C to 1550 ° C. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to the first aspect of the invention, wherein the heat treatment in the step (C) is from 1 minute to 5 hours. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 1, wherein the step (C) further comprises a step (C0): mixing the cerium oxide and aluminum oxide The powder is preheated. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 6, wherein in the step (C0), the preheating temperature is 600 ° C to 800 ° C. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 6, wherein in the step (C0), the preheating time is from 1 second to 1 minute. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to the first aspect of the invention, wherein the step (B) further comprises a step (B1): dry pressing and molding the mixed cerium oxide and Alumina powder. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 1, wherein the cerium oxide powder has a particle diameter of between 1 nm and 1 μm. The method for preparing a particle size adjustable yttrium aluminum garnet powder according to claim 1, wherein the particle size ratio of the cerium oxide and the aluminum oxide powder is [alumina/yttria]=0.5 to 5 .