Method for improving bonding strength of plasma-sprayed Ni60A coating layer on surface of 6061 aluminum alloy

Abstract

The invention relates to a method for improving the bonding strength of a plasma-sprayed Ni60A coating layer on the surface of a 6061 aluminum alloy. The method comprises the steps of sequentially spraying NiCrAlY and Ni60A composite powder to the surface of a matrix, namely the 6061 aluminum alloy by virtue of a plasma spraying technique so as to prepare a NiCrAlY bonding layer and a Ni60A working layer, putting the prepared product into a vacuum furnace, and carrying out thermal treatment. The prepared Ni60A coating layer is high in strength and good in wear resistance, the bonding strength of the coating layer is more than or equal to 30Mpa, the microhardness can reach 1100HV0.1 or above, the wear resistance of the 6061 aluminum alloy matrix is improved, and the service life of the coating layer is effectively prolonged.

Description

technical field

[0001] The invention relates to the field of surface modification of an aluminum alloy substrate, in particular to a method for improving the bonding strength of a plasma sprayed Ni60A coating on the surface of a 6061 aluminum alloy. Background technique

[0002] Aluminum alloy has excellent physical and chemical properties such as light weight, easy processing, and high specific strength, so it is widely used in machinery, automobiles, aerospace and other fields. It is an ideal material for lightweight and energy saving. It is also the second largest type of metal material used in industry after steel. However, aluminum alloy materials have low hardness and poor wear resistance, which limit their further application in industry. Through the surface modification technology, the metal surface structure and properties can be changed, and the matrix can be endowed with new properties, which is of great significance for further expanding the use range of aluminu...

Examples

Embodiment 1

[0025] The preparation process of plasma sprayed Ni60A coating is divided into four stages: substrate surface pretreatment-plasma sprayed NiCrAlY bonding layer-plasma sprayed Ni60A working layer-coating vacuum heat treatment, the bonding layer is made of NiCrAlY composite powder, The thickness of the bonding layer is 100 μm, the working layer is a nickel-based alloy layer made of Ni60A composite powder, the thickness of the working layer is 300 μm, the heat treatment temperature is 150° C., and the holding time is 6 hours. Specific steps are as follows:

[0026] (1) Substrate surface pretreatment

[0027] Use sandpaper to grind the surface of the 6061 aluminum alloy substrate to remove the oxide film on the surface of the substrate until the surface roughness of the aluminum alloy after grinding is Ra<0.8, then rinse the surface of the substrate with alcohol to remove oil and other impurities. Finally, sand blasting equipment is used to roughen the surface of the substrate. ...

Embodiment 2

[0044] The preparation process of plasma sprayed Ni60A coating is divided into four stages: substrate surface pretreatment-plasma sprayed NiCrAlY bonding layer-plasma sprayed Ni60A working layer-coating vacuum heat treatment, the bonding layer is made of NiCrAlY composite powder, The thickness of the bonding layer is 100 μm, the working layer is a nickel-based alloy layer made of Ni60A composite powder, the thickness of the working layer is 300 μm, the heat treatment temperature is 200° C., and the holding time is 6 hours. Specific steps are as follows:

[0045] (1) Substrate surface pretreatment

[0046] Use sandpaper to grind the surface of the 6061 aluminum alloy substrate to remove the oxide film on the surface of the substrate until the surface roughness of the aluminum alloy after grinding is Ra<0.8, then rinse the surface of the substrate with alcohol to remove oil and other impurities. Finally, sand blasting equipment is used to roughen the surface of the substrate. ...

Embodiment 3

[0054] In this example, the bonding strength of the coatings prepared in Example 1 and Example 2 was tested by the bonding tensile method, and the tensile method was tested according to the standard of GB / T8642-2002 "Determination of Tensile Bonding Strength of Thermal Spray Coating". Adopt the acoustic emission detection method to test the adhesion of the NiCrAlY bonding layer prepared by embodiment 1 and embodiment 2 and the substrate, the acoustic emission method adopts the acoustic emission detection of the WS-2005 coating adhesion automatic scratch instrument, and the loading load is 200g , loading time 90s. The microhardness of the coatings prepared in Example 1 and Example 2 was tested with a microhardness tester, with a load of 100 g and a loading time of 15 s. The porosity of the coatings in Example 1 and Example 2 was calculated using a metallographic microscope and Image J2x porosity calculation software, and the test results are shown in Table 3.

technical field

[0001] The invention relates to the field of surface modification of an aluminum alloy substrate, in particular to a method for improving the bonding strength of a plasma sprayed Ni60A coating on the surface of a 6061 aluminum alloy. Background technique

[0002] Aluminum alloy has excellent physical and chemical properties such as light weight, easy processing, and high specific strength, so it is widely used in machinery, automobiles, aerospace and other fields. It is an ideal material for lightweight and energy saving. It is also the second largest type of metal material used in industry after steel. However, aluminum alloy materials have low hardness and poor wear resistance, which limit their further application in industry. Through the surface modification technology, the metal surface structure and properties can be changed, and the matrix can be endowed with new properties, which is of great significance for further expanding the use range of aluminu...

Examples

Embodiment 1

[0025] The preparation process of plasma sprayed Ni60A coating is divided into four stages: substrate surface pretreatment-plasma sprayed NiCrAlY bonding layer-plasma sprayed Ni60A working layer-coating vacuum heat treatment, the bonding layer is made of NiCrAlY composite powder, The thickness of the bonding layer is 100 μm, the working layer is a nickel-based alloy layer made of Ni60A composite powder, the thickness of the working layer is 300 μm, the heat treatment temperature is 150° C., and the holding time is 6 hours. Specific steps are as follows:

[0026] (1) Substrate surface pretreatment

[0027] Use sandpaper to grind the surface of the 6061 aluminum alloy substrate to remove the oxide film on the surface of the substrate until the surface roughness of the aluminum alloy after grinding is Ra<0.8, then rinse the surface of the substrate with alcohol to remove oil and other impurities. Finally, sand blasting equipment is used to roughen the surface of the substrate. ...

Embodiment 2

[0044] The preparation process of plasma sprayed Ni60A coating is divided into four stages: substrate surface pretreatment-plasma sprayed NiCrAlY bonding layer-plasma sprayed Ni60A working layer-coating vacuum heat treatment, the bonding layer is made of NiCrAlY composite powder, The thickness of the bonding layer is 100 μm, the working layer is a nickel-based alloy layer made of Ni60A composite powder, the thickness of the working layer is 300 μm, the heat treatment temperature is 200° C., and the holding time is 6 hours. Specific steps are as follows:

[0045] (1) Substrate surface pretreatment

[0046] Use sandpaper to grind the surface of the 6061 aluminum alloy substrate to remove the oxide film on the surface of the substrate until the surface roughness of the aluminum alloy after grinding is Ra<0.8, then rinse the surface of the substrate with alcohol to remove oil and other impurities. Finally, sand blasting equipment is used to roughen the surface of the substrate. ...

Embodiment 3

[0054] In this example, the bonding strength of the coatings prepared in Example 1 and Example 2 was tested by the bonding tensile method, and the tensile method was tested according to the standard of GB / T8642-2002 "Determination of Tensile Bonding Strength of Thermal Spray Coating". Adopt the acoustic emission detection method to test the adhesion of the NiCrAlY bonding layer prepared by embodiment 1 and embodiment 2 and the substrate, the acoustic emission method adopts the acoustic emission detection of the WS-2005 coating adhesion automatic scratch instrument, and the loading load is 200g , loading time 90s. The microhardness of the coatings prepared in Example 1 and Example 2 was tested with a microhardness tester, with a load of 100 g and a loading time of 15 s. The porosity of the coatings in Example 1 and Example 2 was calculated using a metallographic microscope and Image J2x porosity calculation software, and the test results are shown in Table 3.

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