Filler for blade laser processing protection and preparation method

Abstract

The present invention relates to a filler for blade laser processing protection and a preparation method. The filler comprises the following raw materials in percentage by mass: 50%-70% zircon powder, 20%-30% hexagonal boron nitride, 0.1%-0.3% sodium carboxymethyl cellulose, 9%-20% pure water, 0.01%-0.03% defoaming agent, and 0.01%-0.03% preservative. The filler of the present invention uses a semi-solid paste-like ceramic protective slurry, which has good fluidity, is easy to fill, and can compact the flow channel in the wall; and has a small curing shrinkage ratio, and there is no sintering phenomenon during laser processing. Before the laser processing of the turbine blade, the semi-solid paste-like ceramic protective slurry is filled into the turbine blade cavity, and after heating and drying and curing, it is completely cured to form a solid filler with a certain strength and hardness, thereby protecting the opposite wall of the hole and preventing damage from laser processing; the cured form after heating is easily dispersed by ultrasonic and water cleaning, and can be completely removed without residue.

Description

Technical Field

[0001] The present invention belongs to the field of laser processing, and in particular relates to a filler for blade laser processing protection and a preparation method thereof. Background Art

[0002] Turbine blades are one of the most critical hot-end components of aircraft engines, and their performance directly determines the engine's thrust-to-weight ratio and reliability. Because the operating temperature range of aircraft engine turbine blades exceeds the melting point of high-temperature alloys, film holes are machined into the blades to provide thermal protection and heat dissipation, ensuring proper operation.

[0003] Due to the difficulty of film hole production, laser precision drilling is currently used to create micro-holes on turbine blades. However, turbine blade cavities are complex and small in size, and the laser beam inevitably damages the opposite wall of the hole during the final process. A common solution is to fill the processing cavity with ceramic particles (such as quartz sand) to completely fill the cavity and the micro-flow channel, and then completely compact the fill to prevent laser damage to the wall.

[0004] With the optimization of the turbine blade cavity structure design, the micro-flow channels are becoming more and more complex, but the spatial structure adaptability of ceramic particles is general. The micro-flow channels often have problems such as incomplete filling and loose filling. Wall damage still occurs during laser processing. After processing, the cavity fillings need to be cleaned. Ceramic particles are difficult to dissolve in water or organic solutions and have poor fluidity. The complex micro-flow channels of the blades also increase the difficulty of cleaning. If ceramic particles are stuck in the flow channel, the blade cavity performance will be reduced or even scrapped. Summary of the Invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a filler for blade laser processing protection and a preparation method. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] The present invention provides a filler for blade laser processing protection, comprising the following raw materials in percentage by mass: 50%-70% zircon powder, 20%-30% hexagonal boron nitride, 0.1%-0.3% sodium carboxymethyl cellulose, 9%-20% pure water, 0.01%-0.03% defoaming agent, and 0.01%-0.03% preservative.

[0007] In one embodiment of the present invention, the particle size distribution range of the zircon powder is 325-600 mesh;

[0008] The mass percentage of ZrO2 is greater than 65%.

[0009] In one embodiment of the present invention, the particle size distribution range of the hexagonal boron nitride is less than 1000 mesh;

[0010] The mass percentage of boron nitride is greater than 99%, and the mass percentage of B2O3 impurities is less than 0.5%.

[0011] In one embodiment of the present invention, the sodium carboxymethyl cellulose is sodium carboxymethyl cellulose powder, and its viscosity in a 2% aqueous solution is 0.2-0.5 Pa s.

[0012] In one embodiment of the present invention, the defoaming agent is a silicone defoaming agent.

[0013] The present invention also provides a method for preparing a filler for blade laser processing protection, comprising:

[0014] Step 1: Weigh zircon powder, hexagonal boron nitride, sodium carboxymethyl cellulose, purified water, defoamer and preservative according to the mass percentage of the raw materials in the filler;

[0015] Step 2: Dry-mix zircon powder, hexagonal boron nitride, and sodium carboxymethyl cellulose by forced stirring to obtain a premix;

[0016] Step 3: The premix, purified water, defoaming agent and preservative are ball-milled and stirred to obtain a mixed ceramic slurry, which is used as a filler for blade laser processing protection.

[0017] In one embodiment of the present invention, in step 2, the zircon powder, hexagonal boron nitride and sodium carboxymethyl cellulose are forcedly stirred and dry-mixed using a V-type mixer, and the mixing time is not less than 30 minutes.

[0018] In one embodiment of the present invention, in step 3, the premix, purified water, defoaming agent and preservative are ball-milled and stirred using a circulating stirring ball mill, and the ball milling time is not less than 20 minutes.

[0019] The present invention further provides an application of the filler for blade laser processing protection as described in any of the above embodiments in blade laser processing, comprising:

[0020] Use a syringe to inject the filler into the cavity of the turbine blade, preset the temperature, and cure it under atmospheric conditions of 50-150℃ for a curing time of not less than 2 hours;

[0021] After the blades are laser processed, they are cleaned by ultrasonic and water jet cleaning until the solidified filler is completely removed.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The filler and preparation method for blade laser processing protection of the present invention utilizes a semi-solid, paste-like ceramic protective slurry with good fluidity and ease of filling, capable of compacting the flow channel within the wall. It also exhibits a low cure shrinkage ratio, eliminating sintering during laser processing. Before laser processing of the turbine blade, the semi-solid, paste-like ceramic protective slurry is filled into the turbine blade cavity. After heating and drying, it fully solidifies to form a solid filler with a certain strength and hardness, protecting the opposite wall of the hole and preventing damage from laser processing. The heated, solidified form easily disperses and can be completely removed without residue by ultrasonic and water cleaning.

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of a method for preparing a filler for blade laser processing protection provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description of a filler for blade laser processing protection and a preparation method proposed in accordance with the present invention, in combination with the accompanying drawings and specific implementation methods.

[0027] The aforementioned and other technical contents, features, and effects of the present invention are clearly presented in the following detailed description of the specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a deeper and more specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are provided for reference and illustration purposes only and are not intended to limit the technical solutions of the present invention.

[0028] Example 1

[0029] In this embodiment, a filler for blade laser processing protection includes the following raw materials in the following mass percentages: 50%-70% zircon powder, 20%-30% hexagonal boron nitride, 0.1%-0.3% sodium carboxymethyl cellulose, 9%-20% pure water, 0.01%-0.03% defoaming agent, and 0.01%-0.03% preservative.

[0030] In an optional embodiment, the particle size distribution range of the zircon powder is 325-600 mesh; wherein the mass percentage of ZrO2 is greater than 65%.

[0031] In an optional embodiment, the particle size distribution range of the hexagonal boron nitride is less than 1000 mesh;

[0032] The mass percentage of boron nitride is greater than 99%, and the mass percentage of B2O3 impurities is less than 0.5%.

[0033] In an optional embodiment, the sodium carboxymethyl cellulose is industrial low-viscosity sodium carboxymethyl cellulose powder, and its viscosity in a 2% aqueous solution is 0.2 to 0.5 Pa·s.

[0034] In an optional embodiment, the defoaming agent is an organosilicon defoaming agent, and the preservative is a broad-spectrum preservative.

[0035] It's worth noting that zircon powder, hexagonal boron nitride, and sodium carboxymethyl cellulose serve as the core filler components. Zircon powder, acting as a protective reinforcement, provides laser protection. With a melting point exceeding 2000°C and excellent temperature resistance, zircon powder can be easily formulated into a slurry with a high solid volume fraction and low viscosity, resulting in dense particle packing and preventing laser penetration. Hexagonal boron nitride, a high-melting-point non-oxide ceramic powder with excellent thermal conductivity, serves as the protective matrix. It promotes the fusion of filler components and rapidly dissipates heat generated by the laser during drilling, preventing sintering of the protective filler caused by localized overheating and reducing the difficulty of subsequent removal. Sodium carboxymethyl cellulose, a thickener, acts as a thickener and binds the filler, increasing its viscosity, improving the suspension of the ceramic powder, and providing a bonding function after the slurry is injected into the blade cavity and dries.

[0036] After testing, it was found that under the above ratio, the above components were evenly dispersed and coated with each other after mixing, with more stable performance, optimal fluidity, easy filling, small curing shrinkage ratio, easy removal and non-toxic and environmentally friendly processing.

[0037] Furthermore, a filler composed of the aforementioned main components is injected into the turbine blade cavity via a syringe. After drying, it forms a strong ceramic powder deposit. When a laser beam penetrates the air film hole from one side of the blade, it strikes the impenetrable protective filler, preventing damage to the opposite blade wall and thus achieving blade protection. Because the protective filler does not sinter, it can be easily cleaned using ultrasonic or water jet cleaning methods, leaving no ceramic powder residue and maintaining the physical, chemical, and mechanical properties of the turbine blade.

[0038] Example 2

[0039] See Figure 1 , Figure 1 This is a flow chart of a filler for blade laser processing protection and a preparation method provided by an embodiment of the present invention.

[0040] As shown in the figure, the preparation method of the filler for blade laser processing protection of the present invention is applicable to the above-mentioned filler for blade laser processing protection, including:

[0041] Step 1: Weigh zircon powder, hexagonal boron nitride, sodium carboxymethyl cellulose, purified water, defoamer and preservative according to the mass percentage of the raw materials in the filler;

[0042] Step 2: Dry-mix zircon powder, hexagonal boron nitride, and sodium carboxymethyl cellulose by forced stirring to obtain a premix;

[0043] Step 3: The premix, purified water, defoaming agent and preservative are ball-milled and stirred to obtain a mixed ceramic slurry, which is used as a filler for blade laser processing protection.

[0044] In an optional embodiment, in step 2, the zircon powder, hexagonal boron nitride and sodium carboxymethyl cellulose are forced to stir and dry mix using a V-type mixer, and the mixing time is not less than 30 minutes.

[0045] In an optional embodiment, in step 3, the premix, purified water, defoamer and preservative are ball-milled using a circulating stirring ball mill. Ball milling will reduce the particle size of the materials, further mix the premix evenly and form a paste-like mixed ceramic slurry.

[0046] In an optional embodiment, the ball milling time is not less than 20 min.

[0047] In an optional embodiment, the materials are visually uniformly mixed after ball milling, and the ceramic slurry after ball milling has the following material properties, including:

[0048] Protective performance: The ceramic slurry after ball milling and stirring fills the blade cavity, and has certain strength and protective performance after solidification, and the protective performance is better than the existing filling materials; Flowability: The mixed ceramic slurry after ball milling and stirring is a paste, evenly dispersed, and has good fluidity, and can completely fill the inner cavity of the moving blade by injection or other methods; Reinforcement phase: The reinforcing phase of the mixed ceramic slurry after ball milling and stirring is a high-temperature resistant inert ceramic material, which can significantly enhance the protection against laser after solidification with the protective matrix material; Solid content: The weight percentage of the solid phase of the mixed ceramic slurry after ball milling and stirring is not less than 70%, and the flowability requirements must be met at the same time; Anti-sintering performance: When the laser acts on the ceramic slurry after ball milling and stirring, there will be no sintering or other phenomena, and no large hard particles or flocs will be formed; Cleaning performance: The mixed slurry should be easy to clean after use, and there should be no residue in the blade cavity.

[0049] Example 3

[0050] The application of the filler for blade laser processing protection in this embodiment in blade laser processing includes:

[0051] Use a syringe to inject the filler into the cavity of the turbine blade and cure it under atmospheric conditions of 50-150°C for a curing time of not less than 2 hours;

[0052] After the blades are laser processed, they are cleaned by ultrasonic and water jet cleaning until the solidified filler is completely removed.

[0053] In this embodiment, a syringe is used to inject the filler into the cavity of the turbine blade. First, a medicine spoon is used to fill the mixed ceramic slurry into the syringe in small amounts and multiple times. After the syringe is assembled, it is knocked and vibrated to exhaust and defoam until no obvious bubbles are visible. Steel foil is used to seal the exhaust edge of the turbine blade, and then one of the dust removal holes is pressed. The mixed ceramic slurry is injected from the air inlet of the turbine blade until the mixed ceramic slurry flows out evenly from the reserved dust removal hole. The injection is continuous and the needle is pulled out, and the operation is repeated. After completion, the turbine blade is placed upside down in an oven with the tip facing down. After drying, the air film hole is laser processed. After processing, a water gun is used to cross-rinse from the air inlet and the air film hole direction, and the blade is placed in an ultrasonic cleaning machine. The process is repeated several times and the debris in the inner cavity is sucked out. After drying, the endoscope is used to detect that there is no residue, and the laser processing of the air film hole of the turbine blade is completed.

[0054] Furthermore, the preparation and application of the filler for blade laser processing protection in this embodiment are exemplified.

[0055] Example 1:

[0056] Weigh 5000 g of zircon powder, 3000 g of hexagonal boron nitride, 10 g of sodium carboxymethyl cellulose, 1988 g of purified water, 1 g of defoamer, and 1 g of preservative respectively;

[0057] Zircon powder, hexagonal boron nitride and sodium carboxymethyl cellulose were placed in a V-type mixer and subjected to forced stirring and dry mixing for 30 minutes to obtain a premix;

[0058] Purified water, defoamer and preservative were added to a circulating stirring ball mill, and the premix was added thereto while stirring, and stirring was continued for 30 minutes to obtain a mixed ceramic slurry;

[0059] The filler was injected into the cavity of the turbine blade using a syringe and cured in an oven at 50°C under atmospheric conditions for 5 h;

[0060] The laser processing film hole test of a certain type of directional hollow blade was carried out on the blade. The results showed that the internal microstructure of the blade was not affected by the energy of the laser beam, there was no laser burning phenomenon on the wall, and there was no sand sticking around the prepared film hole, which showed that it had good wall protection function during laser processing.

[0061] After the blades are laser processed, they are cleaned by ultrasonic and water flow, so that the fillers are easily dispersed and separated, and the cleaning is continued until they are completely removed without any residue.

[0062] Example 2:

[0063] Weigh 6000 g of zircon powder, 2500 g of hexagonal boron nitride, 15 g of sodium carboxymethyl cellulose, 1481 g of purified water, 2 g of defoamer, and 2 g of preservative respectively;

[0064] Zircon powder, hexagonal boron nitride and sodium carboxymethyl cellulose were placed in a V-type mixer and subjected to forced stirring and dry mixing for 60 minutes to obtain a premix;

[0065] Purified water, defoamer and preservative were added to a circulating stirring ball mill, and the premix was added thereto while stirring, and stirring was continued for 60 minutes to obtain a mixed ceramic slurry;

[0066] The filler was injected into the cavity of the turbine blade using a syringe and cured in an oven at 100°C under atmospheric conditions for 3 h;

[0067] The laser processing film hole test of a certain type of single crystal hollow blade was carried out. The results showed that the internal microstructure of the blade was not affected by the energy of the laser beam, there was no laser burning phenomenon on the wall, and there was no sand sticking problem around the prepared film hole, which showed that it had good wall protection function during laser processing.

[0068] After the blades are laser processed, they are cleaned by ultrasonic and water flow, so that the fillers are easily dispersed and separated, and the cleaning is continued until they are completely removed without any residue.

[0069] Example 3:

[0070] Weigh 7000g of zircon powder, 2000g of hexagonal boron nitride, 30g of sodium carboxymethyl cellulose, 964g of pure 5 water, 3g of defoamer and 3g of preservative respectively;

[0071] Zircon powder, hexagonal boron nitride and sodium carboxymethyl cellulose were placed in a V-type mixer and subjected to forced stirring and dry mixing for 90 minutes to obtain a premix;

[0072] Add purified water, defoamer and preservative into the circulating stirring ball mill and

[0073] The premix was added thereto and stirred for 90 min to obtain a mixed ceramic slurry. The filler was injected into the cavity of the turbine blade using a syringe and dried in an oven at 150 ° C in the atmosphere.

[0074] Curing for 2h under the conditions;

[0075] The laser processing air film hole test of a certain type of single crystal hollow blade was carried out. The results showed that the internal microstructure of the blade was not affected by the energy of the laser beam and there was no laser burning on the wall.

[0076] There is no sand sticking problem around the prepared air film holes, and it has good wall protection function for laser processing; after the 5 blades are laser processed, the processed blades are ultrasonically and water-washed, and the filler is easily dispersed and detached, and the cleaning is continued until it is completely removed without residue.

[0077] It should be noted that the blade laser processing protective filler and preparation method of this embodiment select different proportions and preparation methods according to the material properties and structural characteristics of the blade, and can meet the protective use requirements in different applications.

[0078] The filler and preparation method for blade laser processing protection according to the embodiment of the present invention use semi-solid

[0079] The semi-solid paste-like ceramic protective slurry has good fluidity and is easy to fill, capable of compacting the flow channel within the wall. It also has a low curing shrinkage ratio, eliminating sintering during laser processing. Before laser processing of the turbine blades, the semi-solid paste-like ceramic protective slurry is filled into the turbine blade cavity. After heating and drying, it completely solidifies to form a solid filler with a certain strength and hardness, protecting the opposite wall of the hole and preventing damage from laser processing. The cured form after heating is easily dispersed and can be completely removed with ultrasonic and water cleaning, leaving no residue.

[0080] It should be noted that, in this document, relational terms such as first and second are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "include," or any other variations thereof are intended to encompass non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not explicitly listed. Without further limitation, an element defined by the phrase "comprising a..." does not preclude the presence of additional identical elements in the article or device comprising the element. Terms such as "connected" or "connected" are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. References to orientations or positional relationships, such as "upper," "lower," "left," and "right," are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate description and simplify the description of the present invention. They do not indicate or imply that the device or element referred to must have, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present invention.

[0081] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A filler for blade laser processing protection, characterized in that: The invention comprises the following raw materials in percentage by mass: 50%-70% zircon powder, 20%-30% hexagonal boron nitride, 0.1%-0.3% sodium carboxymethyl cellulose, 9%-20% purified water, 0.01%-0.03% defoaming agent, and 0.01%-0.03% preservative; The particle size distribution range of the zircon powder is 325-600 mesh; wherein the mass percentage of ZrO2 is greater than 65%; The particle size distribution range of the hexagonal boron nitride is less than 1000 mesh; wherein the mass percentage of boron nitride is greater than 99%, and the mass percentage of B2O3 impurities is less than 0.5%.

2. The filler for blade laser processing protection according to claim 1 is characterized in that: The sodium carboxymethyl cellulose is sodium carboxymethyl cellulose powder, and its viscosity in a 2% aqueous solution is 0.2-0.5 Pa·s.

3. The filler for blade laser processing protection according to claim 1, characterized in that: The defoaming agent is an organosilicon defoaming agent.

4. A method for preparing a filler for blade laser processing protection, applicable to the filler for blade laser processing protection according to any one of claims 1 to 3, characterized in that: include: Step 1: Weigh zircon powder, hexagonal boron nitride, sodium carboxymethyl cellulose, purified water, defoamer and preservative according to the mass percentage of the raw materials in the filler; Step 2: Dry-mix zircon powder, hexagonal boron nitride, and sodium carboxymethyl cellulose by forced stirring to obtain a premix; Step 3: The premix, purified water, defoaming agent and preservative are ball-milled and stirred to obtain a mixed ceramic slurry, which is used as a filler for blade laser processing protection.

5. The method for preparing a filler for blade laser processing protection according to claim 4, characterized in that: In the step 2, the zircon powder, hexagonal boron nitride and sodium carboxymethyl cellulose are forced to stir and dry mix using a V-type mixer, and the mixing time is not less than 30 minutes.

6. The method for preparing a filler for blade laser processing protection according to claim 5, characterized in that: In the step 3, the premix, purified water, defoamer and preservative are ball-milled and stirred using a circulating stirring ball mill, and the ball milling time is not less than 20 minutes.

7. Use of any filler for blade laser processing protection according to any one of claims 1 to 3 in blade laser processing, characterized in that: include: Use a syringe to inject the filler into the cavity of the turbine blade and cure it under atmospheric conditions of 50-150°C for a curing time of not less than 2 hours; After the blades are laser processed, they are cleaned by ultrasonic and water jet cleaning until the solidified filler is completely removed.

Images