A Ni5Al coating inspection method

Abstract

The present invention provides a Ni5Al coating inspection method, comprising the following steps: providing a workpiece, with a Ni5Al coating attached to the surface of the workpiece; embedding a mixed strengthening agent into the Ni5Al coating by a vacuum embedding machine; placing the workpiece in a refrigeration device at a temperature of ‑20°C to ‑18°C for continuous refrigeration for at least 24 hours and then taking it out; observing the workpiece and the Ni5Al coating attached to it through a microscope, and if there is a continuous or obvious dividing line between the workpiece and its corresponding Ni5Al coating, the corresponding workpiece is classified as a defective product. By adopting the technical solution of the present invention, the mixed strengthening agent and the freezing process accelerate the growth and development of cracks hidden inside the Ni5Al coating and make them appear, so that the inspector can observe the clear boundary between the unqualified workpiece and its Ni5Al coating through a microscope when the Ni5Al coating is just formed, thereby prompting the inspector to make an accurate judgment, preventing unqualified workpieces from entering the market, and reducing safety hazards.

Description

Technical Field

[0001] The invention belongs to the technical field of coating inspection, and in particular relates to a Ni5Al coating inspection method. Background Art

[0002] The coating process is widely used. The coating process is mainly used to improve the hardness, wear resistance, corrosion resistance and other properties of alloy materials. However, due to the large difference in affinity between the alloy material and the coating material, some alloy materials are often difficult to plate. For example, aluminum alloy. In order to plate the surface of such difficult-to-plate alloy materials, it is usually necessary to first plate an intermediate coating during the coating process, and then plate other coatings. For example, the publication number is:

[0003] The patent document "CN1291800C" discloses a method for forming a coating, which includes the steps of applying an intermediate coating, a base coating and a clear coating on a substrate in sequence; the technical solution provided by the patent document increases the affinity between the substrate and the base coating and the clear coating by first applying the intermediate coating, thereby enhancing the adhesion of the base coating and the clear coating.

[0004] In the prior art, Ni5Al is a common intermediate coating material. When plating the surfaces of some aviation parts that are difficult to electroplate, Ni5Al coating is first plated on the surfaces of these aviation parts as an intermediate coating, and then other materials are plated. After the Ni5Al coating is formed, the adhesion of the Ni5Al coating needs to be tested. At present, the test of the adhesion of Ni5Al coating generally follows the aviation industry standard HB20195-2014 of the People's Republic of China "Metallographic Inspection of Thermal Spray Coatings". This standard observes the workpiece and its attached Ni5Al coating through a microscope. If there is any difference between the workpiece and its corresponding Ni5Al coating, If there is a continuous or obvious dividing line, the corresponding workpiece will be classified as unqualified. However, the process of Ni5Al coating separating from the workpiece substrate is a slow and long process. When the Ni5Al coating is just formed on the workpiece surface, the Ni5Al coating often presents a stable coating appearance under microscope observation. However, the hidden cracks in the Ni5Al coating have not yet developed, resulting in the inspectors being unable to accurately judge and screen out unqualified products when the Ni5Al coating is just formed, causing unqualified products to flow into the market, posing a great safety hazard. Therefore, there is an urgent need to develop a method that can quickly test the adhesion of Ni5Al coating. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a Ni5Al coating inspection method.

[0006] The present invention is achieved through the following technical solutions.

[0007] The present invention provides a Ni5Al coating inspection method, comprising the following steps:

[0008] Step 1: providing a workpiece, wherein a Ni5Al coating is attached to the surface of the workpiece;

[0009] Step 2: embedding the mixed reinforcing agent into the Ni5Al coating using a vacuum embedding machine;

[0010] Step 3: Place the workpiece in a refrigerator at -20°C to -18°C for at least 24 hours before taking it out;

[0011] Step 4: Observe the workpiece and its attached Ni5Al coating through a microscope. If there is a continuous or obvious boundary line between the workpiece and its corresponding Ni5Al coating, the corresponding workpiece will be classified as unqualified.

[0012] The Ni5Al coating in step 1 is obtained by the following process: plasma spraying is performed on the surface of the workpiece using a plasma spraying device with argon as the main gas and hydrogen as the auxiliary gas, so that Ni5Al powder is sprayed onto the surface of the workpiece through a spray gun to form a Ni5Al coating.

[0013] The process parameters for plasma spraying the workpiece surface are: argon flow rate of 70NLPM, hydrogen flow rate of 10NLPM, and powder feeding flow rate of 4.5NLPM.

[0014] When plasma spraying the workpiece surface, the following steps are performed simultaneously: the workpiece is clamped on a turntable, which is rotated at a speed of 120 rpm about its own central axis. At the same time, the spray gun is moved back and forth along the turntable central axis at a speed of 6 mm / s, and the distance between the spray gun and the workpiece surface is maintained at 160 mm. The angle of the spray gun relative to the workpiece surface is set at 90 degrees. The output power of the plasma spraying equipment is 46 kW.

[0015] Before plasma spraying the workpiece surface, the workpiece surface is first cleaned using an ultrasonic cleaning process.

[0016] The process parameters for cleaning the workpiece surface using an ultrasonic cleaning process are: the cleaning agent is acetone or anhydrous ethanol, the acetone temperature is not lower than 30°C, and the cleaning duration is not less than 15 minutes.

[0017] Before plasma spraying the workpiece surface, a sand blasting process is used to remove the oxide film on the workpiece surface.

[0018] The process parameters for removing the oxide film on the workpiece surface by sand blasting process are as follows: 60# white corundum sand is used as the raw material of the sand blasting flow, the pressure of the sand blasting flow is 0.4MPa, the duration of the sand blasting is 3min to 4min, the impact angle of the sand blasting flow relative to the workpiece surface is 45°, and the distance between the sand blasting flow outlet and the workpiece surface is 100mm.

[0019] The mixed strengthener in step 3 is prepared by uniformly mixing the following components according to corresponding parts by mass: EpoFix epoxy resin: 25 parts; EpoFix curing agent: 3 parts.

[0020] The refrigeration equipment described in step 3 is a refrigerator.

[0021] The beneficial effect of the present invention is that: by adopting the technical solution of the present invention, a mixed strengthening agent is first embedded in the Ni5Al coating, and then the workpiece is frozen. The mixed strengthening agent and the freezing process accelerate the growth and development of cracks hidden in the Ni5Al coating and make them appear, so that inspectors can observe the clear boundary between the unqualified workpiece and its Ni5Al coating through a microscope when the Ni5Al coating is just formed, thereby prompting inspectors to make accurate judgments, preventing unqualified workpieces from entering the market, and reducing safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a process flow chart of the present invention;

[0023] Figure 2 This is a schematic diagram of the arrangement structure of the workpiece, spray gun, and turntable of the present invention;

[0024] Figure 3 This is a photo of the workpiece made of Al2816, observed and taken under a microscope;

[0025] Figure 4 The workpiece is made of Al2816 and is observed and photographed under a microscope after the Ni5Al coating inspection method provided by the present invention is used;

[0026] Figure 5 This is a photo of the workpiece made of 0Cr17Ni14Mo2, observed and taken under a microscope;

[0027] Figure 6 This is a photo of a workpiece made of 0Cr17Ni14Mo2, observed and photographed under a microscope after using the Ni5Al coating inspection method provided by the present invention;

[0028] Figure 7 This is a photo of the workpiece made of GH4169, taken under a microscope;

[0029] Figure 8The workpiece is made of GH4169 and is observed and photographed under a microscope after the Ni5Al coating inspection method provided by the present invention is used;

[0030] Figure 9 This is a photo of the workpiece made of 1Cr11Ni2W2MoV, observed and taken under a microscope;

[0031] Figure 10 This is a photograph of a workpiece made of 1Cr11Ni2W2MoV, observed and photographed under a microscope after using the Ni5Al coating inspection method provided by the present invention;

[0032] Figure 11 This is a photo of the workpiece made of 0Cr18Ni9, observed and taken under a microscope;

[0033] Figure 12 The workpiece material is 0Cr18Ni9, and the Ni5Al coating inspection method provided by the present invention is used to observe and take pictures under a microscope;

[0034] Figure 13 This is a photo of the workpiece made of 1Cr13, observed and taken under a microscope;

[0035] Figure 14 The workpiece is made of 1Cr13 and is observed and photographed under a microscope after the Ni5Al coating inspection method provided by the present invention is used.

[0036] In the figure: 1-workpiece, 2-turntable, 3-spray gun. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0038] like Figure 1 、 Figure 2 As shown, the present invention provides a Ni5Al coating inspection method, comprising the following steps:

[0039] Step 1: providing a workpiece 1, wherein a Ni5Al coating is attached to the surface of the workpiece 1;

[0040] Step 2: embed the mixed reinforcing agent into the Ni5Al coating using a vacuum embedding machine;

[0041] Step 3: Place the workpiece 1 in a refrigerator at -20°C to -18°C for at least 24 hours before taking it out;

[0042] Step 4: Observe the workpiece 1 and the Ni5Al coating attached thereto through a microscope. If there is a continuous or obvious boundary line between the workpiece 1 and its corresponding Ni5Al coating, the corresponding workpiece 1 is classified as a defective product.

[0043] By adopting the technical solution of the present invention, a mixed strengthening agent is first embedded in the Ni5Al coating, and then the workpiece is subjected to a freezing treatment. The mixed strengthening agent and the freezing process accelerate the growth and development of cracks hidden in the Ni5Al coating and make them appear, so that inspectors can observe the clear boundary between the unqualified workpiece and its Ni5Al coating through a microscope when the Ni5Al coating is just formed, thereby prompting inspectors to make accurate judgments, preventing unqualified workpieces from entering the market, and reducing safety hazards.

[0044] Furthermore, in step 1, the Ni5Al coating is obtained by the following process: plasma spraying is performed on the surface of the workpiece 1 using a plasma spraying device with argon as the main gas and hydrogen as the auxiliary gas, so that Ni5Al powder is sprayed through the spray gun 3 and adheres to the surface of the workpiece 1 to form a Ni5Al coating. Preferably, the process parameters for plasma spraying the surface of the workpiece 1 are: argon flow rate of 70 NLPM, hydrogen flow rate of 10 NLPM, and powder feed flow rate of 4.5 NLPM.

[0045] In addition, when plasma spraying the surface of workpiece 1, the following steps are performed simultaneously: workpiece 1 is clamped on turntable 2, which is rotated at 120 rpm around its own central axis. Meanwhile, spray gun 3 is moved up and down along the central axis of turntable 2 at a speed of 6 mm / s. The distance between spray gun 3 and the surface of workpiece 1 is maintained at 160 mm, the angle between spray gun 3 and the surface of workpiece 1 is maintained at 90 degrees, and the output power of the plasma spraying equipment is 46 kW. This allows the Ni5Al coating to be evenly applied to the surface of the workpiece.

[0046] Furthermore, before plasma spraying the workpiece surface, the workpiece surface is first cleaned using an ultrasonic cleaning process. The process parameters for cleaning the workpiece surface using the ultrasonic cleaning process are: the cleaning agent is acetone or anhydrous ethanol, the acetone temperature is not lower than 30°C, and the cleaning duration is not less than 15 minutes.

[0047] In addition, before plasma spraying the workpiece surface, a sandblasting process was used to remove the oxide film on the workpiece surface. The process parameters for sandblasting to remove the oxide film on the workpiece 1 were as follows: 60# white corundum sand was used as the sandblasting stream feedstock, the sandblasting stream pressure was 0.4 MPa, the sandblasting duration was 3 to 4 minutes, the sandblasting stream impact angle relative to the workpiece 1 surface was 45°, and the sandblasting stream outlet was spaced 100 mm from the workpiece 1 surface.

[0048] Furthermore, in step 2, the process parameters for embedding the mixed reinforcing agent into the Ni5Al coating by a vacuum embedding machine are as follows: the output pressure of the vacuum embedding machine is 86 kPa. In step 3, the mixed reinforcing agent is made by uniformly mixing the following components according to corresponding mass fractions: EpoFix epoxy resin: 25 parts; EpoFix curing agent: 3 parts. The refrigeration equipment in step 3 is a refrigerator. The process of embedding the mixed reinforcing agent into the Ni5Al coating and freezing the workpiece accelerates the development of cracks hidden inside the Ni5Al coating and manifests itself within 24 hours, thereby allowing inspectors to make accurate judgments on the adhesion status of the Ni5Al coating within a short period of time after the Ni5Al coating is formed, thereby preventing unqualified workpieces from entering the market and reducing safety hazards.

[0049] In addition, in step 1, the workpiece 1 is made of the following alloys: Al2816, 0Cr17Ni14Mo2, 0Cr18Ni9, GH4169, 1Cr11Ni2W2MoV or 1Cr13. In step 1, the thickness of the Ni5Al coating is not less than 0.17 mm.

[0050] like Figures 3 to 10 As shown, when the workpiece material is Al2816, 0Cr17Ni14Mo2, GH4169, 1Cr11Ni2W2MoV or 1Cr13, the lower part of the photo is the workpiece substrate and the upper part is the Ni5Al coating. Before and after the Ni5Al coating inspection method provided by the present invention is adopted, it can be seen that the image of the workpiece substrate and the image of the Ni5Al coating above are blurred and there is no obvious boundary, indicating that the Ni5Al coating has strong adhesion to the workpiece substrate, the Ni5Al coating has a long adhesion life, and the corresponding workpiece is a qualified product.

[0051] like Figures 11 to 14 As shown, when the workpiece material is 0Cr18Ni9 or 1Cr13, before the Ni5Al coating inspection method provided by the present invention is adopted, the image of the workpiece substrate and the image of the Ni5Al coating above are blurred and there is no obvious boundary. After the Ni5Al coating inspection method provided by the present invention is adopted, there is a clear and significant boundary between the image of the workpiece substrate and the image of the Ni5Al coating above, indicating that the process of embedding the mixed strengthening agent in the Ni5Al coating and freezing the workpiece accelerates the development of hidden cracks inside the Ni5Al coating and manifests itself within 24 hours. The Ni5Al coating has weak adhesion to the workpiece substrate, the Ni5Al coating has a short adhesion life, and the workpiece has a great hidden danger of continued use. The corresponding workpiece is a defective product.

Claims

1. A Ni5Al coating inspection method, characterized in that: The following steps are involved: Step 1: providing a workpiece (1), wherein a Ni5Al coating is attached to the surface of the workpiece (1); Step 2: embedding the mixed reinforcing agent into the Ni5Al coating using a vacuum embedding machine; Step 3: Place the workpiece (1) in a refrigerator at -20°C to -18°C for at least 24 hours before taking it out; Step 4: Observe the workpiece (1) and the Ni5Al coating attached thereto through a microscope. If there is a continuous or obvious boundary line between the workpiece (1) and its corresponding Ni5Al coating, the corresponding workpiece (1) is classified as a defective product. The mixed strengthener in step 3 is prepared by uniformly mixing the following components according to corresponding parts by mass: EpoFix epoxy resin: 25 parts; EpoFix curing agent: 3 parts.

2. The Ni5Al coating inspection method according to claim 1, wherein: The Ni5Al coating in step 1 is obtained by the following process: plasma spraying is performed on the surface of the workpiece (1) using a plasma spraying device with argon as the main gas and hydrogen as the auxiliary gas, so that Ni5Al powder is sprayed through a spray gun (3) and adheres to the surface of the workpiece (1) to form a Ni5Al coating.

3. The Ni5Al coating inspection method according to claim 2, wherein: The process parameters for plasma spraying the surface of the workpiece (1) are: argon flow rate of 70 NLPM, hydrogen flow rate of 10 NLPM, and powder feeding flow rate of 4.5 NLPM.

4. The Ni5Al coating inspection method according to claim 2, wherein: When plasma spraying is performed on the surface of a workpiece (1), the following steps are performed simultaneously: the workpiece (1) is clamped on a turntable (2), the turntable (2) is rotated around its own central axis at a speed of 120 rpm, and the spray gun (3) is moved back and forth up and down along the central axis of the turntable (2) at a speed of 6 mm / s, and the distance between the spray gun (3) and the surface of the workpiece (1) is maintained at 160 mm, and the angle between the spray gun (3) and the surface of the workpiece (1) is maintained at 90 degrees. The output power of the plasma spraying equipment is 46 kW.

5. The Ni5Al coating inspection method according to any one of claims 2 to 4, characterized in that: Before plasma spraying the surface of the workpiece (1), an ultrasonic cleaning process is first used to clean the surface of the workpiece (1).

6. The Ni5Al coating inspection method according to claim 5, characterized in that: The process parameters for cleaning the surface of a workpiece (1) using an ultrasonic cleaning process are as follows: the cleaning agent is acetone or anhydrous ethanol, the acetone temperature is not lower than 30° C., and the cleaning duration is not less than 15 minutes.

7. The Ni5Al coating inspection method according to any one of claims 2 to 4, characterized in that: Before plasma spraying the surface of the workpiece (1), a sand blasting process is first used to remove the oxide film on the surface of the workpiece (1).

8. The Ni5Al coating inspection method according to claim 7, wherein: The process parameters for removing the oxide film on the surface of the workpiece (1) by using the sand blasting process are as follows: 60# white corundum sand particles are used as the raw material of the sand blasting flow, the sand blasting flow pressure is 0.4MPa, the sand blasting duration is 3min to 4min, the impact angle of the sand blasting flow relative to the surface of the workpiece (1) is 45°, and the distance between the sand blasting flow outlet and the surface of the workpiece (1) is 100mm.

9. The Ni5Al coating inspection method according to claim 1, wherein: The refrigeration equipment described in step 3 is a refrigerator.

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