Preparation method of alumina-YAG eutectic melt growth composite material

Abstract

The invention relates to the field of oxide ceramics, and provides a preparation method of an Al2O3-YAG eutectic melt growth composite material. By controlling the seeding temperature, the pulling rate and the rotating speed, convection in the preform melt tends to be stable, a certain degree of super-cooling is formed at the contact position between a seed crystal and the preform melt, and orderly arrangement of crystal atoms at a solid-liquid interface is achieved. As the crystallization process is continuously carried out, new crystals continuously grow out of the melt, atoms in the preformmelt are orderly arranged at the lower end of the seed crystal by pulling the seed crystal, Al2O3 and YAG phases can form stable single-orientation crystals (single crystals), and directional solidification is realized. The provided preparation method can obtain the Al2O3-YAG eutectic melt growth composite material which is free of pores, smooth and compact in surface, uniform in phase distribution and high in relative density and texturing degree; and moreover, the eutectic material grown by the method is relatively large in size.

Description

technical field

[0001] The invention relates to the field of oxide ceramics, in particular to a method for preparing an alumina-YAG eutectic melt growth composite material. Background technique

[0002] After nitrides, carbides, borides and carbon / carbon ceramic-based high-temperature thermal structural materials, Al 2 o 3 -YAG eutectic ceramics have entered people's field of vision for their natural outstanding high-temperature oxidation resistance, excellent bending strength performance, oxidation resistance and creep resistance at temperatures close to their melting point. Traditional Al 2 o 3 -YAG ceramics are mainly prepared by powder sintering method. However, this method usually cannot obtain single crystal constituent phases, and most of the prepared polycrystalline structures are polycrystalline, and there are weak bonds between the powder particles of the polycrystalline structure and between the constituent phases. The connection interface and a large number o...

Examples

preparation example Construction

[0035] The invention provides an Al 2 o 3 -The preparation method of YAG eutectic melt growth composite material, comprises the following steps:

[0036] (1) Al 2 o 3 Powder and Y 2 o 3 The powder is ball-milled and then dried in the presence of a binder and an alcoholic solvent to obtain a mixed powder;

[0037](2) The mixed powder is sequentially subjected to pressing and sintering and then cooled to obtain a preform;

[0038] (3) In the temperature field, the seed crystal is immersed in the melt of the preform by using the rotating pulling method, and then undergoes seeding, necking, shouldering, equal diameter growth and finishing in sequence to obtain Al 2 o 3 - YAG eutectic melt growth composite material;

[0039] The seeding temperature is 1770-1780° C., the pulling speed is 0.1-5 mm / h, and the rotation speed is 5-25 r / min.

[0040] The present invention will Al 2 o 3 Powder and Y 2 o 3 The powder is ball milled and then dried in the presence of a binder an...

Embodiment 1

[0060] (1) Select high-purity micron grade Al 2 o 3 (99.99% pure), Y 2 o 3 (purity 99.99%) powder by Al 2 o 3 / Y 2 o 3 =81.5 / 18.5 molar ratio to prepare raw materials, where Al 2 o 3 The particle size of the powder is 1~2μm, Y 2 o 3 The particle size of the powder is 1-2 μm. First put the original powder in a drying oven at 90°C for 3 hours, and then use an electronic balance to weigh 100g of Al according to the above ratio. 2 o 3 and Y 2 o 3 powder, put the above powder into a ball mill jar for ball milling, and add 20mL polyvinyl alcohol binder and 60mL absolute ethanol to the ball mill jar at the same time, wherein the polyvinyl alcohol binder consists of polyvinyl alcohol and water, and polyvinyl alcohol and water The dosage ratio is 1g:20mL, ball milling starts after standing for 5min, the ball milling medium is zirconia, the ball-to-material ratio is 2:1, the ball milling speed is 550r / min, and the ball milling time is 6h to obtain a powder slurry; then the ...

Embodiment 2

[0067] (1) Select high-purity micron grade Al 2 o 3 (99.99% pure), Y 2 o 3 (purity 99.99%) powder by Al 2 o 3 / Y 2 o 3 =81.5 / 18.5 molar ratio to prepare raw materials, where Al 2 o 3 The particle size of the powder is 1~2μm, Y 2 o 3 The particle size of the powder is 1-2 μm. First put the original powder in a drying oven at 90°C for 3 hours, and then use an electronic balance to weigh 100g of Al according to the above ratio. 2 o 3 and Y 2 o 3 powder, put the above powder into a ball mill jar for ball milling, and add 20mL polyvinyl alcohol binder and 60mL absolute ethanol to the ball mill jar at the same time, wherein the polyvinyl alcohol binder consists of polyvinyl alcohol and water, and polyvinyl alcohol and water The dosage ratio is 1g:20mL, and ball milling starts after standing for 5min. The ball milling medium is zirconia, the ball-to-material ratio is 3:1, the ball milling speed is 550r / min, and the ball milling time is 6h to obtain a powder slurry; then ...

technical field

[0001] The invention relates to the field of oxide ceramics, in particular to a method for preparing an alumina-YAG eutectic melt growth composite material. Background technique

[0002] After nitrides, carbides, borides and carbon / carbon ceramic-based high-temperature thermal structural materials, Al 2 o 3 -YAG eutectic ceramics have entered people's field of vision for their natural outstanding high-temperature oxidation resistance, excellent bending strength performance, oxidation resistance and creep resistance at temperatures close to their melting point. Traditional Al 2 o 3 -YAG ceramics are mainly prepared by powder sintering method. However, this method usually cannot obtain single crystal constituent phases, and most of the prepared polycrystalline structures are polycrystalline, and there are weak bonds between the powder particles of the polycrystalline structure and between the constituent phases. The connection interface and a large number o...

Examples

preparation example Construction

[0035] The invention provides an Al 2 o 3 -The preparation method of YAG eutectic melt growth composite material, comprises the following steps:

[0036] (1) Al 2 o 3 Powder and Y 2 o 3 The powder is ball-milled and then dried in the presence of a binder and an alcoholic solvent to obtain a mixed powder;

[0037](2) The mixed powder is sequentially subjected to pressing and sintering and then cooled to obtain a preform;

[0038] (3) In the temperature field, the seed crystal is immersed in the melt of the preform by using the rotating pulling method, and then undergoes seeding, necking, shouldering, equal diameter growth and finishing in sequence to obtain Al 2 o 3 - YAG eutectic melt growth composite material;

[0039] The seeding temperature is 1770-1780° C., the pulling speed is 0.1-5 mm / h, and the rotation speed is 5-25 r / min.

[0040] The present invention will Al 2 o 3 Powder and Y 2 o 3 The powder is ball milled and then dried in the presence of a binder an...

Embodiment 1

[0060] (1) Select high-purity micron grade Al 2 o 3 (99.99% pure), Y 2 o 3 (purity 99.99%) powder by Al 2 o 3 / Y 2 o 3 =81.5 / 18.5 molar ratio to prepare raw materials, where Al 2 o 3 The particle size of the powder is 1~2μm, Y 2 o 3 The particle size of the powder is 1-2 μm. First put the original powder in a drying oven at 90°C for 3 hours, and then use an electronic balance to weigh 100g of Al according to the above ratio. 2 o 3 and Y 2 o 3 powder, put the above powder into a ball mill jar for ball milling, and add 20mL polyvinyl alcohol binder and 60mL absolute ethanol to the ball mill jar at the same time, wherein the polyvinyl alcohol binder consists of polyvinyl alcohol and water, and polyvinyl alcohol and water The dosage ratio is 1g:20mL, ball milling starts after standing for 5min, the ball milling medium is zirconia, the ball-to-material ratio is 2:1, the ball milling speed is 550r / min, and the ball milling time is 6h to obtain a powder slurry; then the ...

Embodiment 2

[0067] (1) Select high-purity micron grade Al 2 o 3 (99.99% pure), Y 2 o 3 (purity 99.99%) powder by Al 2 o 3 / Y 2 o 3 =81.5 / 18.5 molar ratio to prepare raw materials, where Al 2 o 3 The particle size of the powder is 1~2μm, Y 2 o 3 The particle size of the powder is 1-2 μm. First put the original powder in a drying oven at 90°C for 3 hours, and then use an electronic balance to weigh 100g of Al according to the above ratio. 2 o 3 and Y 2 o 3 powder, put the above powder into a ball mill jar for ball milling, and add 20mL polyvinyl alcohol binder and 60mL absolute ethanol to the ball mill jar at the same time, wherein the polyvinyl alcohol binder consists of polyvinyl alcohol and water, and polyvinyl alcohol and water The dosage ratio is 1g:20mL, and ball milling starts after standing for 5min. The ball milling medium is zirconia, the ball-to-material ratio is 3:1, the ball milling speed is 550r / min, and the ball milling time is 6h to obtain a powder slurry; then ...

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