Preparation method and application of aluminum alloy hard anodic oxidation self-lubricating film layer

Abstract

The invention discloses a preparation method of an aluminum alloy hard anodic oxidation self-lubricating film layer. The preparation method comprises the following steps: S1, preparing an oxidation film layer on the surface of an aluminum alloy by adopting a hard anodic oxidation process; and S2, the hard anodic oxidation self-lubricating film layer is prepared through a static deposition method. The invention further discloses application of the hard anodic oxidation self-lubricating film layer prepared through the preparation method of the aluminum alloy hard anodic oxidation self-lubricating film layer to treatment of the aluminum alloy mechanical part surface. The hardness, the corrosion resistance and the self-lubricating performance are improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal surface protective coatings, and in particular to a preparation method and application of an aluminum alloy hard anodized self-lubricating film layer. Background Art

[0002] The hard anodized film has extremely high hardness and wear resistance, can resist various mechanical wear and impact, and has excellent corrosion resistance, and can effectively resist the erosion of chemical substances.

[0003] In addition, its good electrical insulation properties make it have important application value in electrical and electronic equipment. These advantages make hard anodized film widely used in aviation, machinery manufacturing, electronics industry and other fields, becoming an ideal choice for protecting aluminum alloy metal surfaces and improving product performance.

[0004] However, with the development of modern science and technology, hard anodizing with single performance cannot meet the requirements of industrial development. For dry vacuum pump products, hard anodizing is not only required to have high hardness and corrosion resistance, but also to have low surface roughness and self-lubricating properties, so that the dry vacuum pump has excellent dynamic sealing performance under oil-free lubrication conditions.

[0005] At present, the method to enhance the lubrication performance of the hard anodized film layer is to use inorganic salt material heat sealing treatment and spray PTFE. This method has a good lubrication effect in the initial stage, but after long-term use, the lubrication layer will fall off, wear and fall off. Among them, the spray PTFE film layer has poor high temperature resistance.

[0006] Therefore, a preparation method and application of an aluminum alloy hard anodized self-lubricating film layer are provided. Summary of the invention

[0007] The purpose of the present invention is to overcome the existing defects and provide a preparation method and application of an aluminum alloy hard anodized self-lubricating film layer, thereby improving the hardness, corrosion resistance and self-lubricating performance.

[0008] The technical solution to achieve the above purpose is: A method for preparing an aluminum alloy hard anodized self-lubricating film layer according to the present invention comprises: Step S1, preparing an oxide film layer on the surface of the aluminum alloy by using a hard anodizing process; Step S2, preparing a hard anodized self-lubricating film layer by a static deposition method.

[0009] Preferably, the step S1 comprises: Step S11, degreasing to remove liquid and solid grease pollutants on the surface of the aluminum alloy; Step S12, first washing with water to remove the degreasing solution on the surface of the aluminum alloy; Step S13, pickling treatment to remove the oxide film naturally formed on the surface of the aluminum alloy; Step S14, secondary water washing to remove the pickling solution on the surface of the aluminum alloy; Step S15, neutralization treatment to remove the acid solution remaining on the surface of the aluminum alloy; Step S16, washing with water three times to remove the neutralizing solution on the surface of the aluminum alloy; Step S17, hard anodizing treatment to prepare an oxide film on the surface of the aluminum alloy; Step S18, washing with water four times to remove the hard anodizing solution on the surface of the aluminum alloy; Step S19, expanding the hole to increase the diameter of the inner hole of the oxide film; Step S20, finally washing with water, using ultrasonic method to wash twice to remove the acid in the pores, and then prepare an oxide film layer on the surface of the aluminum alloy.

[0010] Preferably, in step S11, the degreasing solution formula is: 4g / L NaOH, 25g / L Na 3 PO 4 , 5g / L Na 2 SiO 4 , the remainder is H 2 O, conductivity>18.0MΩ / cm; degreasing solution temperature is 50±3℃, degreasing time is 4±1min, and degreasing solution pH is 12±0.5; In step S12, the first water washing requires: Aqueous solution conductivity>18.0MΩ / cm, pH>5.5; The first washing process needs to be carried out twice. The first washing temperature is 35±3℃, the first washing time is 15±5s, and the second washing temperature is 25±3℃, the second washing time is 10±5s; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by the bursting force of the bubbles; In step S13, the pickling solution formula is: 250ml / L HNO 3 ; The pickling temperature is 27±3℃, and the pickling time is 60±10s.

[0011] Preferably, in step S14, the secondary washing requires: The conductivity of the aqueous solution is less than 1500 μm / cm, the washing time is 10±5s, and the pH value is greater than 5.5; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by the bursting force of the bubbles; In step S15, the neutralization solution formula is: NaHCO3 Solution; neutralization temperature is 27±3℃, neutralization time is 3±2min; In step S16, the three water washing requirements are: Aqueous solution conductivity <1500μm / cm, pH value >6.0; Three water washes require two water washes, and the washing time is 10±5s; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by using the bursting force of the bubbles.

[0012] Preferably, in step S17, the hard anodizing solution formula is: 0.6-1.2 mol / L H 2 SO 4 , current density is 14.1±0.7%, 5.6-21g / L Al 3+ , voltage is 0-60V; In step S18, the four water washing requirements are: The conductivity of the aqueous solution is less than 1500 μm / cm, the washing time is 10±5s, and the pH value is greater than 5.0; In step S19, the acid solution formula required for hole expansion is: 3 PO 4 Solution, expansion temperature is 40±3℃, expansion time is 30±2min; In step S20, the final washing requirement is: The conductivity of the aqueous solution is <1500μm / cm, the washing time is 48±3min, and the pH is >6.0.

[0013] Preferably, the step S2 comprises: Step S21, particle deposition, PTFE particles are sucked into the pores; Step S22, drying, hot air drying the aluminum alloy, and finally obtaining a hard anodized self-lubricating film layer.

[0014] Preferably, in step S21, nano-PTFE dispersion is used for particle deposition, and the formula of nano-PTFE dispersion is: 50 g / L (NH 4 ) 2 SO 4 , 25wt.% SDBS, 2.5mg / ml PTFE particles; the particle deposition solution pH>5.5, the particle deposition temperature is 40±3℃, and the particle deposition time is 2h±10min; In step S22, the hot air drying temperature is 100±10°C and the drying time is 3min±10s.

[0015] The second aspect of the present invention is a method for preparing a hard anodized self-lubricating film layer of aluminum alloy. The prepared hard anodized self-lubricating film layer is applied to the surface treatment of mechanical parts made of aluminum alloy.

[0016] The beneficial effects of the present invention are as follows: the present invention adopts a hard anodizing process to prepare an oxide layer on the surface of an aluminum alloy substrate, the oxide layer thickness is about 30 μm, the film cross-sectional hardness is ≥450 HV, the film average roughness is ≤Ra0.7 μm, and the film presents a porous structure; the porous structure film is expanded by an acid immersion method, and the size of the structure after treatment is increased; a nano-PTFE dispersion is added, the dispersion can be evenly distributed in the plating solution, and a static deposition method is used to absorb PTFE particles into the pores by utilizing the porous film and capillary adsorption; the present invention is not limited to PTFE particles, and graphite particles and molybdenum disulfide particles with lubricating properties are suitable for this method; the hard anodized self-lubricating film prepared by the present invention can effectively improve the surface hardness and corrosion resistance of aluminum alloy parts, and the addition of PTFE particles can improve the self-lubricating performance of the film; it can provide good lubrication performance for dynamic sealing structure equipment and reduce the rapid loss of friction pairs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of a method for preparing a hard anodized self-lubricating film layer of an aluminum alloy according to the present invention; Figure 2 It is a specific flow chart of preparing an oxide film layer on the surface of an aluminum alloy by using a hard anodizing process in the present invention; Figure 3 This is a specific flow chart of the static deposition method used in the present invention to prepare a hard anodized self-lubricating film layer; Figure 4 It is a scanning electron microscope image of the oxide film after the surface of the aluminum alloy substrate in the present invention is processed by hard anodizing process; Figure 5 This is an electron microscope image of the oxide film after the hole expansion treatment in the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] like Figure 1 As shown, a method for preparing an aluminum alloy hard anodized self-lubricating film layer comprises: Step S1, preparing an oxide film layer on the surface of the aluminum alloy by using a hard anodizing process.

[0021] like Figure 2 As shown, step S1 includes: Step S11, degreasing, removing liquid and solid grease pollutants on the surface of the aluminum alloy.

[0022] In the embodiment, the degreasing solution formula is: 4g / L NaOH, 25g / L Na 3 PO 4 , 5g / L Na 2 SiO 4 , the remainder is H 2 O, conductivity>18.0MΩ / cm; degreasing solution temperature is 50±3℃, degreasing time is 4±1min, and degreasing solution pH is 12±0.5.

[0023] Step S12, first washing with water to remove the degreasing solution on the surface of the aluminum alloy.

[0024] In the embodiment, the first water washing requires: Aqueous solution conductivity>18.0MΩ / cm, pH>5.5; The first washing process needs to be carried out twice. The first washing temperature is 35±3℃, the first washing time is 15±5s, and the second washing temperature is 25±3℃, the second washing time is 10±5s; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by using the bursting force of the bubbles.

[0025] Step S13, pickling treatment to remove the oxide film naturally formed on the surface of the aluminum alloy.

[0026] In the embodiment, the pickling solution formula is: 250ml / L HNO 3 ; The pickling temperature is 27±3℃, and the pickling time is 60±10s.

[0027] Step S14: secondary water washing to remove the pickling solution on the surface of the aluminum alloy.

[0028] In the embodiment, the secondary washing requires: The conductivity of the aqueous solution is less than 1500 μm / cm, the washing time is 10±5s, and the pH value is greater than 5.5; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by using the bursting force of the bubbles.

[0029] Step S15: neutralization treatment to remove the acid liquid remaining on the surface of the aluminum alloy.

[0030] In the embodiment, the neutralization solution formula is: NaHCO 3 Solution; neutralization temperature is 27±3℃, neutralization time is 3±2min.

[0031] Step S16, washing with water three times to remove the neutralizing solution on the surface of the aluminum alloy.

[0032] In the embodiment, three washings require: Aqueous solution conductivity <1500μm / cm, pH value >6.0; Three water washes require two water washes, and the washing time is 10±5s; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by using the bursting force of the bubbles.

[0033] Step S17, hard anodizing treatment to prepare an oxide film on the surface of the aluminum alloy.

[0034] In the embodiment, the hard anodizing solution formula is: 0.6-1.2 mol / L H 2 SO 4 , current density is 14.1±0.7%, 5.6-21g / L Al 3+ , voltage is 0-60V.

[0035] Step S18, washing with water four times to remove the hard anodizing solution on the surface of the aluminum alloy.

[0036] In the embodiment, four washings require: The conductivity of the aqueous solution is <1500μm / cm, the washing time is 10±5s, and the pH value is >5.0.

[0037] Step S19, expanding the hole to increase the diameter of the inner hole of the oxide film.

[0038] In the embodiment, the acid solution formula required for hole expansion is: 3 PO 4 solution, the pore expansion temperature is 40±3℃, and the pore expansion time is 30±2min.

[0039] Step S20, finally washing with water, using ultrasonic method to wash twice to remove the acid in the pores, and then prepare an oxide film layer on the surface of the aluminum alloy.

[0040] In the embodiment, the final washing requirement is: The conductivity of the aqueous solution is <1500μm / cm, the washing time is 48±3min, and the pH is >6.0.

[0041] like Figure 4 As shown, this is a scanning electron microscope image of the oxide film after the surface of the aluminum alloy substrate has been treated with hard anodizing.

[0042] like Figure 5 As shown, this is an electron microscope picture of the oxide film after hole expansion treatment.

[0043] Step S2, preparing a hard anodized self-lubricating film layer by a static deposition method.

[0044] like Figure 3 As shown, step S2 includes: Step S21, particle deposition, PTFE particles are sucked into the pores.

[0045] In the embodiment, nano-PTFE dispersion is used for particle deposition, and the formula of nano-PTFE dispersion is: 50 g / L (NH 4 ) 2 SO 4 , 25wt.% SDBS, 2.5mg / ml PTFE particles; the particle deposition solution pH>5.5, the particle deposition temperature is 40±3℃, and the particle deposition time is 2h±10min.

[0046] Step S22, drying, hot air drying the aluminum alloy, and finally obtaining a hard anodized self-lubricating film layer.

[0047] In the embodiment, the hot air drying temperature is 100±10° C. and the time is 3 min±10 s.

[0048] A method for preparing an aluminum alloy hard anodized self-lubricating film layer. The prepared hard anodized self-lubricating film layer is used for treating the surface of aluminum alloy mechanical parts.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a hard anodized self-lubricating film layer of aluminum alloy, characterized in that: include: Step S1, preparing an oxide film layer on the surface of the aluminum alloy by using a hard anodizing process; Step S2, preparing a hard anodized self-lubricating film layer by a static deposition method.

2. The method for preparing a hard anodized self-lubricating film layer of aluminum alloy according to claim 1, characterized in that: The step S1 comprises: Step S11, degreasing to remove liquid and solid grease pollutants on the surface of the aluminum alloy; Step S12, first washing with water to remove the degreasing solution on the surface of the aluminum alloy; Step S13, pickling treatment to remove the oxide film naturally formed on the surface of the aluminum alloy; Step S14, secondary water washing to remove the pickling solution on the surface of the aluminum alloy; Step S15, neutralization treatment to remove the acid solution remaining on the surface of the aluminum alloy; Step S16, washing with water three times to remove the neutralizing solution on the surface of the aluminum alloy; Step S17, hard anodizing treatment to prepare an oxide film on the surface of the aluminum alloy; Step S18, washing with water four times to remove the hard anodizing solution on the surface of the aluminum alloy; Step S19, expanding the hole to increase the diameter of the inner hole of the oxide film; Step S20, finally washing with water, using ultrasonic method to wash twice to remove the acid in the pores, and then prepare an oxide film layer on the surface of the aluminum alloy.

3. The method for preparing a hard anodized self-lubricating film layer of aluminum alloy according to claim 2, characterized in that: In the step S11, the degreasing solution formula is: 4g / L NaOH, 25g / L Na3PO4, 5g / L Na2SiO4, and the rest is H2O, and the conductivity is greater than 18.0MΩ / cm; the degreasing solution temperature is 50±3°C, the degreasing time is 4±1min, and the degreasing solution pH value is 12±0.5; In step S12, the first water washing requires: Aqueous solution conductivity>18.0MΩ / cm, pH>5.5; The first washing process needs to be carried out twice. The first washing temperature is 35±3℃, the first washing time is 15±5s, and the second washing temperature is 25±3℃, the second washing time is 10±5s; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by the bursting force of the bubbles; In step S13, the pickling solution formula is: 250 ml / L HNO3; the pickling temperature is 27±3°C, and the pickling time is 60±10s.

4. The method for preparing a hard anodized self-lubricating film layer of aluminum alloy according to claim 2, characterized in that: In step S14, the secondary washing requires: The conductivity of the aqueous solution is less than 1500 μm / cm, the washing time is 10±5s, and the pH value is greater than 5.5; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by the bursting force of the bubbles; In step S15, the neutralization solution formula is: NaHCO3 solution; the neutralization temperature is 27±3°C, and the neutralization time is 3±2min; In step S16, the three water washing requirements are: Aqueous solution conductivity <1500μm / cm, pH value >6.0; Three water washes require two water washes, and the washing time is 10±5s; Compressed air is injected into the bottom of the washing tank to generate tiny bubbles, and the cleaning work is completed by using the bursting force of the bubbles.

5. The method for preparing a hard anodized self-lubricating film layer of aluminum alloy according to claim 2, characterized in that: In step S17, the hard anodizing solution formula is: 0.6-1.2 mol / L H2SO4, current density is 14.1±0.7%, 5.6-21 g / L Al 3+ , voltage is 0-60V; In step S18, the four water washing requirements are: The conductivity of the aqueous solution is less than 1500 μm / cm, the washing time is 10±5s, and the pH value is greater than 5.0; In step S19, the acid solution formula required for hole expansion is: H3PO4 solution, the hole expansion temperature is 40±3°C, and the hole expansion time is 30±2min; In step S20, the final washing requirement is: The conductivity of the aqueous solution is <1500μm / cm, the washing time is 48±3min, and the pH is >6.

0.

6. The method for preparing an aluminum alloy hard anodized self-lubricating film according to claim 1, characterized in that: The step S2 comprises: Step S21, particle deposition, PTFE particles are sucked into the pores; Step S22, drying, hot air drying the aluminum alloy, and finally obtaining a hard anodized self-lubricating film layer.

7. The method for preparing an aluminum alloy hard anodized self-lubricating film according to claim 6, characterized in that: In the step S21, nano-PTFE dispersion is used for particle deposition, the formula of the nano-PTFE dispersion is: 50 g / L (NH4)2SO4, 25 wt.% SDBS, 2.5 mg / ml PTFE particles; the particle deposition solution pH is greater than 5.5, the particle deposition temperature is 40±3°C, and the particle deposition time is 2h±10min; In step S22, the hot air drying temperature is 100±10°C and the drying time is 3min±10s.

8. A hard anodized self-lubricating film layer prepared by the method for preparing an aluminum alloy hard anodized self-lubricating film layer according to claims 1-7 is used for treating the surface of aluminum alloy mechanical parts.

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