CN103706784A - Agglomerated composite powder for high-temperature abradable seal coating and preparation method thereof - Google Patents

Abstract

The invention relates to an agglomerated composite powder for thermal spraying high-temperature wearable sealing coating and a preparation method thereof. Through the methods of mechanical ball milling, bonding at room temperature and agglomeration, the agglomerated composite powder with good adaptability to spraying process was prepared. The powder contains MCrAlY alloy powder, alloy powder with β-NiAl intermetallic compound as the main phase, polyphenylester powder, boron nitride and binder. The raw material can be a combination of these materials, and the binder can be either inorganic or organic. The powder contains β-NiAl intermetallic compound high-temperature resistant components, which can increase the heat-resistant temperature of existing metal-based sealing coatings. Compared with ceramic sealing coatings, the coating has excellent thermal shock resistance and can be used for a long time Under the high temperature condition of 1000°C. The powder has wide application in sealing the gas path of the high temperature part of the gas turbine, especially the high pressure turbine part.

Description

Agglomerated composite powder for high temperature abradable sealing coating and preparation method thereof

technical field

The invention relates to the field of thermal spraying materials, in particular to an agglomerated composite powder for a high-temperature abradable sealing coating and a preparation method thereof.

Background technique

In order to improve the efficiency of gas turbines and reduce fuel consumption, gas path sealing technology is an important means. As an important gas path sealing technology, abradable sealing coating has been widely used in gas turbines. At present, there are nearly twenty kinds of abradable sealing coating materials. In the low-to-medium temperature section of gas turbines, the existing abradable sealing coating materials can meet the requirements of use, but in the high-temperature parts of gas turbines, especially the high-pressure turbine parts, The working temperature reaches or even exceeds 1000°C. Due to the harsh working conditions of high temperature and high pressure, the coating will quickly fail due to corrosion, oxidation and thermal fatigue, which cannot meet the requirements of advanced gas turbines.

Existing sealing coating materials are composed of framework materials that provide the bonding strength between the coating and the substrate, maintain the structural integrity of the coating, and provide the coating with erosion resistance, oxidation resistance, and corrosion resistance, and provide coatings that can It is composed of abrasive and anti-friction lubricating filler phase materials. The skeleton materials mainly include aluminum, copper, titanium, nickel, chromium and other metal elements and their alloys. The filler phase materials mainly include polyester plastic, graphite, hexagonal boron nitride, etc. At present, the high-temperature sealing coating materials used in gas turbines mainly include NiCrAl/bentonite, NiCrAl/diatomaceous earth, NiCrFeAl/hBN, CoNiCrAlY/hBN, etc. Due to the lack of high-temperature oxidation resistance of such coating materials, the prepared coating The maximum operating temperature of the layer is lower than 850°C, which cannot meet the operating requirements of the high-pressure turbine at around 1000°C.

In addition, the high-temperature abradable sealing coating material for plasma spraying with the publication number CN101659800B is a ceramic sealing coating prepared by using zirconia ceramic powder and polyphenylester. Although the heat-resistant temperature can reach above 1000 ° C, due to the The thermal matching between the coating and the superalloy substrate of the gas turbine is poor, and the thermal fatigue resistance of the coating is insufficient, and it will fall off after short-term cold and hot cycles, which cannot meet the service life requirements.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, and provide a high-temperature sealing coating material with good thermal fatigue resistance and a preparation method thereof.

The purpose of the present invention is achieved through the following technical solutions:

Agglomerated composite powder for high-temperature abradable sealing coating, formed by agglomerating structural components, abradable components and adhesives, characterized in that the structural components are β-NiAl intermetallic compounds or β-NiAl A mixture of intermetallic compounds and MCrAlY alloy powders (M is one or more of metal elements Fe, Co, Ni), and the abradable component is polyester powder or a mixture of polyester powder and hexagonal boron nitride powder , the weight of the binder accounts for 1-10% of the weight of the raw material, the weight of the abradable component accounts for 5-30% of the weight of the raw material, and the structural component is the balance.

In some embodiments, the adhesive is any organic adhesive selected from polyvinylpyrrolidone, methyl ethyl glue, alkyd varnish, or any one selected from water glass, aluminum dihydrogen phosphate Inorganic adhesive.

In some embodiments, the polyester powder is polyphenylene or polyamide.

In some embodiments, when the structural component is a mixture of β-NiAl intermetallic compound and MCrAlY alloy powder, the weight ratio of β-NiAl intermetallic compound and MCrAlY alloy powder is 1˜10:1.

In some embodiments, when the abradable component is a mixture of polyester powder and hexagonal boron nitride powder, the weight ratio of polyester powder to hexagonal boron nitride powder is 1˜10:1.

The present invention also provides a method for preparing an agglomerated composite powder for a high-temperature abradable sealing coating, the method comprising the following steps:

(1) Fully and evenly mix the structural components and the abradable components;

(2) Add the binder to the well-mixed structural components and wearable components while stirring, and continue stirring until the powder is granulated;

(3) Keep drying at 50-150°C for 1-5 hours, and sieve to obtain the finished product.

In some embodiments, after stirring in step (2) until the powder is granulated, the powder is initially sieved, and then dried at 50-150° C. for 1-5 hours.

In some embodiments, the binder is dispersed in a solvent prior to addition, and then added to the mixed powder together with the solvent.

In some embodiments, the binder is added at one time or several times, intermittently or continuously.

Compared with the prior art, the present invention has the following innovations:

1. Add alloy powder with β-NiAl as the main phase in the powder component;

2. Prepare composite powder by mechanical agglomeration method.

Compared with the prior art, the present invention has the following significant advantages:

1. The addition of alloy powder with β-NiAl as the main phase significantly improves the high temperature oxidation resistance of the material.

2. The metal skeleton material has good thermal matching with the superalloy substrate, which significantly improves the service life of the high-temperature sealing coating.

3. The composite powder is prepared by the agglomeration process, which significantly improves the uniformity of the structure and performance of the coating prepared by the powder.

Detailed ways

The present invention will be further described below by way of examples.

Example 1

Raw material composition: structural component: β-NiAl intermetallic compound; abradable component: polyphenylene; adhesive: polyvinylpyrrolidone.

Raw material ratio: 5wt% of abradable components, 1wt% of adhesives, and the balance of structural components.

Preparation method: Mix the structural component and the wearable component by ball milling for more than 12 hours. After the components are evenly mixed, take out the powder for use. The binder is then added while stirring. When stirring, use a "one-shaped" type stirring paddle with a length of 30-50cm, and a flat-bottomed mixing tank with an inner diameter of 40-80cm. min. The binder is added at one time. Stir the material continuously until the raw material powder is agglomerated into granules. Use a 30-mesh sieve to sieve the granulated powder, and put the sieved material back into the mixing tank for stirring until all the powder can pass through the sieve. Spread the sieved powder on a tray, dry in an oven at 50-80°C for 2 hours, and sieve the dried powder with a 30-mesh sieve to obtain a finished product.

Example 2

Raw material composition: structural component: mixture of β-NiAl intermetallic compound and MCrAlY alloy powder, the weight ratio of β-NiAl intermetallic compound and MCrAlY alloy powder is 1:1; abradable component: polyamide and hexagonal boron nitride A mixture of polyamide and hexagonal boron nitride in a weight ratio of 10:1; adhesive: A-B glue.

Raw material ratio: 10wt% of abradable components, 2wt% of adhesives, and the balance of structural components.

Preparation method: Mechanically stir and mix the structural component and the wearable component for more than 12 hours. After the components are evenly mixed, take out the powder for use. binder. When stirring, use a "one-shaped" stirring paddle with a length of 30-50 cm, and a flat-bottomed mixing tank with an inner diameter of 40-80 cm. The thickness of the material must not exceed one-third of the height of the inner diameter of the mixing tank. min. The binder is added at one time. Stir the material continuously until the raw material powder is agglomerated into granules, and dry in an oven at 50-80°C for 2 hours. The dried powder is sieved with a 30-mesh sieve to obtain a finished product.

Example 3

Raw material composition: structural component: mixture of β-NiAl intermetallic compound and MCrAlY alloy powder, the weight ratio of β-NiAl intermetallic compound and MCrAlY alloy powder is 3:1; abradable component: polyamide and hexagonal boron nitride A mixture of polyamide and hexagonal boron nitride in a weight ratio of 3:1; adhesive: alkyd varnish.

Raw material ratio: 15wt% of abradable components, 3wt% of adhesives, and the balance of structural components.

Preparation method: Mix the structural component and the wearable component by ball milling for more than 12 hours. After the components are evenly mixed, take out the powder for use. binder. When stirring, use a "one-shaped" stirring paddle with a length of 30-50 cm, and a flat-bottomed mixing tank with an inner diameter of 40-80 cm. The thickness of the material must not exceed one-third of the height of the inner diameter of the mixing tank. min. The binder is added in two times, the first addition is 30-50% of the total binder, and the remaining binder is added after the first binder and powder are mixed evenly. Stir the material continuously until the raw material powder is agglomerated into granules. Use a 30-mesh sieve to sieve the granulated powder, and put the sieved material back into the mixing tank for stirring until all the powder can pass through the sieve. Spread the sieved powder on a tray, dry in an oven at 50-80°C for 2 hours, and sieve the dried powder with a 30-mesh sieve to obtain a finished product.

Example 4

Raw material composition: structural component: a mixture of β-NiAl intermetallic compound and MCrAlY alloy powder, the weight ratio of β-NiAl intermetallic compound and MCrAlY alloy powder is 5:1; abradable component: polyphenylene ester; adhesive : Water glass.

Raw material ratio: 20wt% of abradable components, 5wt% of adhesives, and the balance of structural components.

Preparation method: Mix the structural component and the wearable component by ball milling for more than 12 hours. After the components are evenly mixed, take out the powder for use. binder. When stirring, use a "one-shaped" type stirring paddle with a length of 30-50cm, and a flat-bottomed mixing tank with an inner diameter of 40-80cm. min. The binder is added in two times, the first addition is 30-50% of the total binder, and the remaining binder is added after the first binder and powder are mixed evenly. Stir the material continuously until the raw material powder is agglomerated into granules. Use a 30-mesh sieve to sieve the granulated powder, and put the sieved material back into the mixing tank for stirring until all the powder can pass through the sieve. Spread the sieved powder on a tray, dry in an oven at 80-150°C for 2 hours, and sieve the dried powder with a 30-mesh sieve to obtain a finished product.

Example 5

Raw material composition: structural component: mixture of β-NiAl intermetallic compound and MCrAlY alloy powder, the weight ratio of β-NiAl intermetallic compound and MCrAlY alloy powder is 10:1; abradable component: polyphenylene ester and hexagonal nitride Boron mixture, the weight ratio of polyphenylene ester and hexagonal boron nitride is 5:1; binder: aluminum dihydrogen phosphate.

Raw material ratio: 30wt% of abradable components, 10wt% of adhesives, and the balance of structural components.

Preparation method: Mix the structural component and the wearable component by ball milling for more than 12 hours. After the components are evenly mixed, take out the powder for use. binder. When stirring, use a "one-shaped" stirring paddle with a length of 30-50 cm, and a flat-bottomed mixing tank with an inner diameter of 40-80 cm. The thickness of the material must not exceed one-third of the height of the inner diameter of the mixing tank. min. The binder is added in two times, the first addition is 30-50% of the total binder, and the remaining binder is added after the first binder and powder are mixed evenly. Continue to stir the material until the raw material powder is agglomerated into granules. Use a 30-mesh screen to sieve the granulated powder, and put the sieved material back into the mixing tank for stirring until all the powder can pass through the sieve. Spread the sieved powder on a tray, dry in an oven at 80-150°C for 2 hours, and sieve the dried powder with a 30-mesh sieve to obtain a finished product.

Claims (9)

1. high-temperature abradable seal coating Conglobation type composite powder, by structural constituent, can wear away component and bonding agent and reunite and form, it is characterized in that, described structural constituent is the mixture of β-NiAl intermetallic compound or β-NiAl intermetallic compound and MCrAlY alloy powder, describedly wear away the mixture that component is polyester powder or polyester powder and hexagonal boron nitride powder, weight of binder accounts for 1～10% of raw material weight, can wear away composition weight and account for 5～30% of raw material weight, structural constituent is surplus.

2. high-temperature abradable seal coating according to claim 1 Conglobation type composite powder, it is characterized in that, described bonding agent is any organic adhesive being selected from polyvinylpyrrolidone, the first and second glue, alkyd varnish, or for being selected from any inorganic adhesive in waterglass, aluminium dihydrogen phosphate.

3. high-temperature abradable seal coating according to claim 1 Conglobation type composite powder, is characterized in that, described polyester powder is polybenzoate or polyamide.

4. high-temperature abradable seal coating according to claim 1 Conglobation type composite powder, it is characterized in that, when described structural constituent is the mixture of β-NiAl intermetallic compound and MCrAlY alloy powder, the weight ratio of β-NiAl intermetallic compound and MCrAlY alloy powder is 1～10: 1.

5. high-temperature abradable seal coating according to claim 1 Conglobation type composite powder, it is characterized in that, described when wearing away component and being the mixture of polyester powder and hexagonal boron nitride powder, the weight ratio of polyester powder and hexagonal boron nitride powder is 1～10: 1.

6. the preparation method with Conglobation type composite powder according to the high-temperature abradable seal coating described in the arbitrary claim of claim 1-5, is characterized in that, said method comprising the steps of:

(1) by structural constituent and can wear away the full and uniform mixing of component;

(2) by the structural constituent mixing and can wear away component, when stirring, add binding agent, proceed to be stirred to powder granulating;

(3) at 50～150 ℃, keep drying for 1～5 hour, screening is processed, and makes finished product.

7. preparation method according to claim 6, is characterized in that, in step (2), is stirred to after powder granulating, powder is tentatively sieved, then keep drying for 1～5 hour at 50～150 ℃.

8. preparation method according to claim 6, is characterized in that, described binding agent is first dispersed in solvent before adding, and then jointly joins in mixed-powder with solvent.

9. preparation method according to claim 6, is characterized in that, described binding agent is disposablely to add or add several times, intermittently adds or adds continuously.