CN105802459A - Cobalt aluminate paint, cobalt aluminate paint preparing method and ceramic core manufacturing method - Google Patents

Abstract

The invention discloses a cobalt aluminate coating, which comprises the following components in weight percentage: 20-40% cobalt aluminate, 15-20% polyethylene glycol, 30-40% deionized water, 5-10% ammonium dihydrogen phosphate, 0-20% alumina, 0.5-1% defoamer. It refines and refines the surface grains of castings. Also disclosed are a preparation method of the cobalt aluminate paint and a method of manufacturing a ceramic core.

Description

Cobalt aluminate coating, preparation method of cobalt aluminate coating, and ceramic core manufacturing method

technical field

The invention relates to the precision casting technology of superalloy components, in particular to cobalt aluminate paint, a preparation method of the cobalt aluminate paint and a ceramic core manufacturing method.

Background technique

At present, the manufacturing of turbine blades for gas turbines focuses on equiaxed crystals, columnar crystals, and single crystals, but the application of equiaxed crystals is still the mainstream. The manufacture of equiaxed grain turbine blades is mainly concentrated on fine-grain casting, and the smaller the grain size, the better. The surface grain refinement technology of castings is also quite mature. For iron-based alloys, the industry widely adopts the casting mold surface to brush aluminum method of acid cobalt paint. However, the refinement of the internal grains of the casting is equally important to the improvement of the quality of the casting, and the refinement of the internal grains of the casting is conducive to greatly improving the comprehensive performance of the casting.

For this reason, it is desirable to seek a technical solution to at least alleviate the existing problems.

Contents of the invention

On the one hand, the technical problem to be solved by the present invention is to provide a cobalt aluminate coating capable of refining the crystal grains on the casting surface.

On the other hand, the technical problem to be solved by the present invention is to provide a preparation method of cobalt aluminate coating.

In another aspect, the technical problem to be solved by the present invention is to provide a method for manufacturing a ceramic core.

In order to solve the technical problem on the one hand, the present invention adopts the following technical solutions.

A cobalt aluminate paint, comprising the following components by weight percentage: 20-40% cobalt aluminate, 15-20% polyethylene glycol, 30-40% deionized water, 5-10% diphosphate Ammonium hydrogen, 0-20% alumina, 0.5-1% defoamer.

The particle size of the cobalt aluminate is 300-400 mesh.

In order to solve another technical problem, the present invention adopts the following technical solutions.

A preparation method for cobalt aluminate paint, comprising the following steps:

Step 1, taking the following components by weight percentage: 20-40% cobalt aluminate, 15-20% polyethylene glycol and 30-40% deionized water, and then mixing the aforementioned components uniformly to obtain a mixture;

Step 2, adding 5-10% by weight of ammonium dihydrogen phosphate and 0-20% by weight of alumina to the mixture obtained in step 1 and mixing uniformly; and

Step 3, adding 0.5-1% by weight defoamer to the mixture obtained in Step 2 and mixing uniformly to obtain the cobalt aluminate coating.

In the first step, each component is uniformly mixed by using a core ball mill.

In the second step, each component is uniformly mixed by using a core ball mill.

In the third step, a vacuum mixer is used to mix the components evenly.

The particle size of the cobalt aluminate is 300-400 mesh.

In order to solve the technical problem in another aspect, the present invention adopts the following technical solutions.

A method for manufacturing a ceramic core, comprising the steps of:

S1, preparing a ceramic core smaller than the relative theoretical size of 0.05-0.5mm;

S2, adopting the preparation method of the above-mentioned cobalt aluminate paint to obtain the cobalt aluminate paint;

S3, uniformly coating the cobalt aluminate coating obtained in S2 on the surface of the ceramic core prepared in S1; and

S4, after drying the ceramic core obtained in S3, pre-sintering the ceramic core at a temperature of 700-900° C. for 1-2 hours to obtain a ceramic core coated with a fine-grained cobalt aluminate coating.

The coating construction method in S3 is as follows: the ceramic core prepared in S1 is immersed in the cobalt aluminate coating obtained in S2 for at least 1 hour under the condition of a vacuum of 1-5 Pa by dipping method, or Spraying method The surface of the ceramic core prepared in S1 is sprayed with a coating with a thickness of 0.05-0.1 mm using a spray gun.

The drying method in S4 is as follows: drying the ceramic core obtained in S3 at room temperature for 4-5 hours, or keeping it warm at 100-130° C. for 1-2 hours.

The present invention has the following beneficial technical effects.

The comparative experiments show that the cobalt aluminate coating of the present invention can effectively refine the internal surface grains of the casting and greatly improve the comprehensive performance of the casting. By adopting the manufacturing method of the ceramic core of the present invention, the surface of the ceramic core is treated with a cobalt aluminate coating. During construction, the inner cavity of the casting is in contact with the fine-grained cobalt aluminate coating on the outer layer of the ceramic core, thereby making the crystal of the casting The grains are also refined.

Description of drawings

Fig. 1 is a metallographic image of the cavity surface of a casting prepared without using the ceramic core of the present invention.

Fig. 2 is a metallographic image of the cavity surface of a casting prepared by using the ceramic core of the present invention.

detailed description

In order to describe the technical features and functions of the present invention in detail and realize them according to the content of this specification, the implementation of the present invention will be further described below in conjunction with the accompanying drawings.

Implementation 1

A kind of cobalt aluminate paint of the present invention, comprises the component of following percentage by weight: 20% cobalt aluminate, 15% polyethylene glycol, 40% deionized water, 10% ammonium dihydrogen phosphate, 14.5% Aluminum oxide, 0.5% defoamer.

Example 2

A kind of cobalt aluminate coating of the present invention, comprises the component of following percentage by weight: 40% cobalt aluminate, 20% polyethylene glycol, 30% deionized water, 9% ammonium dihydrogen phosphate, 0% Aluminum oxide, 1% defoamer.

Example 3

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 25% cobalt aluminate, 17% polyethylene glycol, 33% deionized water, 5% ammonium dihydrogen phosphate, 19.5% Aluminum oxide, 0.5% defoamer.

Example 4

A cobalt aluminate coating of the present invention comprises the following components in weight percent: 30% cobalt aluminate, 19% polyethylene glycol, 35.2% deionized water, 7% ammonium dihydrogen phosphate, 8.1% Aluminum oxide, 0.7% defoamer.

Example 5

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 35% cobalt aluminate, 16.6% polyethylene glycol, 34.3% deionized water, 8.2% ammonium dihydrogen phosphate, 5% Aluminum oxide, 0.9% defoamer.

Example 6

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 22.5% cobalt aluminate, 16% polyethylene glycol, 36% deionized water, 6% ammonium dihydrogen phosphate, 18.9% Aluminum oxide, 0.6% defoamer.

Example 7

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 27.5% cobalt aluminate, 18% polyethylene glycol, 37.5% deionized water, 9.5% ammonium dihydrogen phosphate, 6.7% Aluminum oxide, 0.8% defoamer.

Example 8

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 32.5% cobalt aluminate, 15.1% polyethylene glycol, 35.4% deionized water, 5.5% ammonium dihydrogen phosphate, 10.7% Aluminum oxide, 0.8% defoamer.

Example 9

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 23.8% cobalt aluminate, 15.1% polyethylene glycol, 38.9% deionized water, 5% ammonium dihydrogen phosphate, 16.7% Aluminum oxide, 0.5% defoamer.

Example 10

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 37.2% cobalt aluminate, 15.1% polyethylene glycol, 38.9% deionized water, 5% ammonium dihydrogen phosphate, 3.3% Aluminum oxide, 0.5% defoamer.

Example 11

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 24.5% cobalt aluminate, 17% polyethylene glycol, 33% deionized water, 5% ammonium dihydrogen phosphate, 20% Aluminum oxide, 0.5% defoamer.

Example 12

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 28% cobalt aluminate, 17% polyethylene glycol, 32% deionized water, 5% ammonium dihydrogen phosphate, 17.5% Aluminum oxide, 0.5% defoamer.

Example 13

A cobalt aluminate coating of the present invention comprises the following components in weight percentage: 38.3% cobalt aluminate, 17% polyethylene glycol, 32% deionized water, 5% ammonium dihydrogen phosphate, 7.2% Aluminum oxide, 0.5% defoamer.

In the above embodiments, the particle size of the cobalt aluminate is preferably 300-400 mesh.

Example 14

A kind of preparation method of cobalt aluminate coating of the present invention comprises the following steps:

Step 1, take cobalt aluminate, polyethylene glycol and deionized water according to the weight percentage in the above-mentioned embodiment 1, and then mix the cobalt aluminate, polyethylene glycol and deionized water in a planetary ball mill to obtain a mixture, generally In some cases, it can be mixed evenly after mixing for 30-60 minutes; wherein, the particle size of cobalt aluminate is preferably 300-400 mesh.

Step 2: Add ammonium dihydrogen phosphate and aluminum oxide to the mixture obtained in the previous step 1 according to the weight percentage in the above example 1, and continue mixing in the planetary ball mill until the mixture is evenly mixed. Generally, mix for at least 15 minutes Mix well.

Step 3, take out the mixture homogeneously mixed in step 2, add the antifoaming agent according to the weight percentage in the above-mentioned embodiment 1 to the mixture homogeneously mixed in step 2 taken out, and then place it in a vacuum mixer to fully stir and mix evenly to obtain Cobalt aluminate paint.

Examples 15-26

For the preparation methods of other cobalt aluminate coatings of the present invention, according to the steps of Example 14, each component is taken according to the weight percentage in Examples 2-13 to obtain the corresponding cobalt aluminate coatings.

Example 27

A kind of ceramic core manufacturing method of the present invention, comprises the following steps:

S1, preparing a ceramic core smaller than the relative theoretical size of 0.05-0.5mm;

S2, using any of the above preparation methods for cobalt aluminate coatings to obtain cobalt aluminate coatings;

S3, uniformly coating the cobalt aluminate coating obtained in S2 on the surface of the ceramic core prepared in S1;

S4, after the ceramic core obtained in S3 is dried, the ceramic core is pre-sintered at a temperature of 700-900°C for 1-2 hours to obtain a ceramic core coated with a fine-grained cobalt aluminate coating.

In some embodiments, the above-mentioned coating construction method in S3 is: dipping the ceramic core prepared in S1 into the cobalt aluminate coating obtained in S2 for at least 1 hour under the condition of a vacuum of 1-5 Pa. , or use a spraying method to spray a coating with a thickness of 0.05-0.1mm on the surface of the ceramic core prepared in S1 with a spray gun.

In some embodiments, the drying method in S4 is as follows: drying the ceramic core obtained in S3 at room temperature for 4-5 hours, or keeping it warm in an environment at a temperature of 100-130° C. for 1-2 hours.

Fig. 1 is a metallographic image of the cavity surface of a casting prepared without using the ceramic core of the present invention. The grain size of the surface of the casting inner cavity formed by the ceramic core is between Φ 3-8 mm, and the average grain size is Φ 5.5 mm.

Fig. 2 is a metallographic image of the cavity surface of a casting prepared by using the ceramic core of the present invention. Under the same pouring conditions, the grain size of the surface of the casting inner cavity formed by the shrinkage of the ceramic core is between Φ0.5-3.5mm, and the average grain size is Φ2mm.

It can be seen that the use of the cobalt aluminate coating and the ceramic core manufacturing method of the present invention can effectively refine the crystal grains on the surface of the inner cavity of the casting.

It should be noted that the various specific technical features described in the above specific implementation manners may be combined in any suitable manner if there is no contradiction. Various specific technical features described in different specific implementation manners may also be combined in any suitable manner if there is no contradiction. In order to avoid unnecessary repetition, various possible combinations are not described in the present invention.

The present invention has been described in detail above with reference to the embodiments, which are illustrative rather than restrictive. Changes and modifications without departing from the general concept of the present invention are within the protection scope of the present invention.

Claims (10)

1. a cobalt aluminate coating, it is characterised in that include the cobalt aluminate of following components in percentage by weight: 20-40%, the Polyethylene Glycol of 15-20%, the deionized water of 30-40%, the ammonium dihydrogen phosphate of 5-10%, the aluminium oxide of 0-20%, the defoamer of 0.5-1%.

Cobalt aluminate coating the most according to claim 1, it is characterised in that the grain graininess of described cobalt aluminate is 300-400 mesh.

3. the preparation method of a cobalt aluminate coating, it is characterised in that comprise the following steps:

Step one, takes the cobalt aluminate of following components in percentage by weight: 20-40%, the Polyethylene Glycol of 15-20% and the deionized water of 30-40%, more aforementioned each component mix homogeneously is obtained mixture；

Step 2, joins in the mixture obtained by described step one and mix homogeneously by the ammonium dihydrogen phosphate of 5-10% percentage by weight, the aluminium oxide of 0-20% percentage by weight；And

Step 3, joins in the mixture obtained by described step 2 by the defoamer of 0.5-1% percentage by weight and mix homogeneously obtains described cobalt aluminate coating.

Preparation method the most according to claim 3, it is characterised in that in described step one, uses core ball mill by each component mix homogeneously.

Preparation method the most according to claim 3, it is characterised in that in described step 2, uses core ball mill by each component mix homogeneously.

Preparation method the most according to claim 3, it is characterised in that in described step 3, uses de-airing mixer by each component mix homogeneously.

7. according to the preparation method described in any one of claim 3 to 6, it is characterised in that the grain graininess of described cobalt aluminate is 300-400 mesh.

8. a ceramic core manufacture method, it is characterised in that comprise the following steps:

S1, preparation is less than the ceramic core of relative theory size 0.05-0.5mm；

S2, uses the preparation method described in any one of claim 3 to 6 to obtain cobalt aluminate coating；

S3, the cobalt aluminate coating obtained by the surface of the ceramic core prepared by described S1 uniformly coats described S2；And

S4, the ceramic core obtained by described S3 is dried, and this ceramic core obtained under 700-900 DEG C of temperature conditions the ceramic core of Surface coating carefully brilliant cobalt aluminate coating through presintering in 1-2 hour.

Ceramic core manufacture method the most according to claim 8, it is characterized in that, coating construction method in described S3 is: at least 1h in the cobalt aluminate coating obtained by using infusion process that the ceramic core prepared by described S1 immerses under conditions of vacuum is 1-5pa described S2, or uses spraying process to use spray gun spraying thickness to be the coating of 0.05-0.1mm on the surface of the ceramic core prepared by S1.

Ceramic core manufacture method the most according to claim 8 or claim 9, it is characterised in that in described S4, drying means is: the ceramic core obtaining described S3 is dried 4-5 hour at ambient temperature, or in the environment that temperature is 100-130 DEG C, it is incubated 1-2h.