Aluminum alloy friction plate and preparation method thereof

Abstract

The invention relates to an aluminum alloy friction plate and a preparation method thereof, and belongs to the technical field of friction plates, the aluminum alloy friction plate comprises an aluminum alloy, a hard anodic oxidation film layer and a lubricating film layer, and optionally, the aluminum alloy friction plate further comprises a middle layer. The aluminum alloy friction plate has better wear resistance and pressure resistance, and meanwhile, the raw materials and the preparation method of the aluminum alloy friction plate are simple.

Description

Technical Field

[0001] This application relates to the field of friction plates, and particularly to an aluminum alloy friction plate and a preparation method thereof. Background Art

[0002] Friction plates are materials that rely on frictional action to perform braking and transmission functions. Their main function is to absorb or transmit power through friction, enabling mechanical equipment and motor vehicles to work safely and reliably. To meet the usage requirements of high-load wet gearboxes of large power machinery such as military vehicles, heavy mining machinery, and excavators, friction plates generally use paper-based and copper-based friction plates. Copper-based friction plates have good compressive strength, heat resistance, and wear resistance, but their friction coefficient is relatively low. Paper-based friction plates have good friction coefficients, wear resistance, certain heat resistance, and mechanical strength. However, their structural load-bearing pressure capacity is limited, their oil compatibility is poor, they have large wear, and their service life is short. In addition, the processes of copper and paper-based friction plates are complex, requiring many control links, which affects the production speed.

[0003] Therefore, there is an urgent need in this field to study a friction plate with good friction coefficients, better wear resistance and pressure resistance, and a simple preparation process. Summary of the Invention

[0004] The purpose of this application is to provide an aluminum alloy friction plate and a preparation method thereof, which can have both wear resistance and pressure resistance, and the required raw materials and preparation methods are simple.

[0005] In the first aspect, this application provides an aluminum alloy friction plate, adopting the following technical solution: An aluminum alloy friction plate includes aluminum alloy, a hard anodic oxidation film layer, and a lubricating film layer.

[0006] By adopting the above technical solution, this application uses aluminum alloy as the friction plate matrix, combined with a hard anodic oxidation film layer and a lubricating film layer, and can have good strength and friction coefficient without an additional strength support core plate. Therefore, it can be prepared thinner. When the braking torque is insufficient, it is easier to increase the number of friction pairs.

[0007] Optionally, the aluminum alloy uses magnesium and silicon as the main alloying elements and uses the Mg2Si phase as the strengthening phase.

[0008] Optionally, the aluminum alloy contains the following components by weight percentage: Si 0.4 - 2%; Mg 0.8 - 3%; aluminum 94 - 99%.

[0009] By adopting the above technical solution, the main alloying elements of the aluminum alloy are magnesium and silicon, which have good weldability, high hardness (up to HB90 or more), and good oxidation effect, and are very suitable for aluminum alloy friction plates.

[0010] Optionally, the thickness of the hard anodic oxidation film layer is 45 - 55 μm, and the hardness value is ≥500 HV.

[0011] Optionally, the lubricating film layer is a polytetrafluoroethylene film.

[0012] By adopting the above technical solution, the aluminum alloy friction plate of the present application is high temperature resistant, does not undergo thermal decomposition, and has good thermal stability.

[0013] Optionally, the aluminum alloy friction plate further includes an intermediate layer, wherein the intermediate layer is between the hard anodic oxidation film layer and the lubricating film layer.

[0014] Optionally, the intermediate layer is one or more of SiC or ZIF - 8.

[0015] By adopting the above technical solution, by adding one or more of SiC or ZIF - 8 in the intermediate layer, the pressure resistance and wear resistance are significantly improved.

[0016] In a second aspect, the present application provides a brake friction pair, which is made of more than one pair of the above - mentioned aluminum alloy friction plates.

[0017] By adopting the above technical solution, when the braking torque is insufficient, it can be achieved by increasing the number of friction pairs made of friction plates.

[0018] In a third aspect, the present application provides a preparation method of an aluminum alloy friction plate, adopting the following technical solution: Step S1, sandblast the surface of the aluminum alloy; Step S2, perform hard anodic oxidation on the aluminum alloy in an electrolyte solution of H2SO4 and oxalic acid solution to obtain an aluminum alloy substrate with a hard anodic oxidation film layer completely covering the surface; Step S3, after washing the aluminum alloy substrate obtained in step S2, immerse it for 15 - 30 min to form a lubricating film layer, take it out and dry it at 250 - 300 °C for 20 - 40 min to obtain the aluminum alloy friction plate.

[0019] By adopting the above technical solution, the preparation process of the aluminum alloy friction plate of the present application is simple, uses less raw materials compared with the friction plates of the prior art, and is suitable for large - scale production.

[0020] In a fourth aspect, the present application provides a preparation method of an aluminum alloy friction plate, adopting the following technical solution: Step S1, sandblast the surface of the aluminum alloy; Step S2, perform hard anodic oxidation on the aluminum alloy in an electrolyte solution of H2SO4 and oxalic acid solution to obtain an aluminum alloy substrate with a hard anodic oxidation film layer completely covering the surface; Step S3: After washing the aluminum alloy substrate obtained in step S2 with water, immerse it for 1 - 3 h to form an intermediate layer, uniformly coat the intermediate layer on the hard anodic oxidation film, and then take it out; Step S4: After rinsing the aluminum alloy substrate obtained in step S3 with ethanol, immerse it in a polytetrafluoroethylene emulsion. After 15 - 30 min of immersion, take it out and dry it at 250 - 300 °C for 20 - 40 min to obtain the aluminum alloy friction plate.

[0021] By adopting the above technical solution, on the basis of the third aspect, an intermediate layer structure is added, which not only significantly improves the thermal stability and / or wear resistance, but also has a simple preparation process and is suitable for large-scale production.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: 1. The aluminum alloy friction plate of the present application has a multi-layer structure, which increases the hardness of the aluminum alloy and significantly improves the wear resistance of the aluminum alloy friction plate; 2. The aluminum alloy friction plate of the present application can withstand a large surface pressure, and can reduce the thickness of the substrate while ensuring the strength of the substrate, thereby increasing the number of friction pairs; 3. The preparation process of the aluminum alloy friction plate of the present application is simple and suitable for large-scale production. Specific Embodiments

[0023] The present application will be described below through examples, but the present application is not limited thereto. The experimental methods shown in the following examples are all conventional methods unless otherwise specified. The reagents and materials shown without indicating the manufacturer can all be obtained as conventional products through commercial purchase.

[0024] Example 1 The raw material is 6061T6 aluminum alloy. The 6061 - T6 series is an aluminum, magnesium, silicon alloy (main component content: Si: 0.4 - 0.8%; Mg: 0.8 - 1.2%; the rest is basically aluminum), which is a heat-treatable corrosion-resistant alloy with good strength, corrosion resistance and uniformity. 6061 - T6 is in the state of artificial aging after solution heat treatment.

[0025] Step S1: Pretreatment. Sandblast the surface of the aluminum alloy, select W60 alumina fine sand, and the surface roughness Ra after treatment is 3.9.

[0026] Step S2: Hard anodic oxidation treatment. Add 20 g / L oxalic acid to 15% H2SO4 electrolyte to perform hard anodic oxidation on the aluminum alloy to obtain an aluminum alloy substrate with a hard anodic oxidation film layer completely covering the surface. Among them, the temperature of the hard anodic oxidation is 2 °C, the current is 2.5 A, and the oxidation time is 40 min.

[0027] Step S3: Sealing treatment. After washing the aluminum alloy substrate obtained in Step S2 with water, immerse it in an emulsion containing 35% polytetrafluoroethylene by mass. After 30 minutes of immersion, take it out and dry it at 250 °C for 40 minutes to obtain the aluminum alloy friction plate.

[0028] Example 2 The raw material is 6061T6 aluminum alloy. The 6061-T6 series is an aluminum, magnesium, silicon alloy (main component content: Si: 0.4 - 0.8%; Mg: 0.8 - 1.2%; the rest is basically aluminum), which is a heat-treatable corrosion-resistant alloy with good strength, corrosion resistance, and uniformity. 6061-T6 is in the state of artificial aging after solution heat treatment.

[0029] Step S1: Pretreatment. Sandblast the surface of the aluminum alloy, select W60 alumina fine sand, and the surface roughness Ra after treatment is 3.9.

[0030] Step S2: Hard anodizing treatment. Add 20 g / L oxalic acid to 15% H2SO4 electrolyte to perform hard anodizing on the aluminum alloy to obtain an aluminum alloy substrate with a hard anodized film layer covering the entire surface. Among them, the temperature of hard anodizing is 2 °C, the current is 2.5 A, and the oxidation time is 40 minutes.

[0031] Step S3: Sealing treatment 1. After washing the aluminum alloy substrate obtained in Step S2 with water, immerse it in an emulsion containing 30% SiC by mass. After 1 hour of immersion, take it out.

[0032] Step S4: Sealing treatment 2. After rinsing the aluminum alloy substrate obtained in Step S3 with ethanol, immerse it in an emulsion containing 25% polytetrafluoroethylene by mass. After 15 minutes of immersion, take it out and dry it at 300 °C for 20 minutes to obtain the aluminum alloy friction plate.

[0033] Example 3 The raw material is 6061T6 aluminum alloy. The 6061-T6 series is an aluminum, magnesium, silicon alloy (main component content: Si: 0.4 - 0.8%; Mg: 0.8 - 1.2%; the rest is basically aluminum), which is a heat-treatable corrosion-resistant alloy with good strength, corrosion resistance, and uniformity. 6061-T6 is in the state of artificial aging after solution heat treatment.

[0034] Step S1: Pretreatment. Sandblast the surface of the aluminum alloy, select W60 alumina fine sand, and the surface roughness Ra after treatment is 3.9.

[0035] Step S2: Hard anodizing treatment. Add 20 g / L of oxalic acid to 15% H2SO4 electrolyte and perform hard anodizing on the aluminum alloy to obtain an aluminum alloy substrate with a hard anodized film layer covering the entire surface. Among them, the temperature of the hard anodizing is 2 °C, the current is 2.5 A, and the oxidation time is 40 min.

[0036] Step S3: Sealing treatment 1. After washing the aluminum alloy substrate obtained in Step S2 with water, immerse it in a ZIF-8 solution (weigh 0.50 g of zinc nitrate hexahydrate and 0.33 g of 2-methylimidazole, measure 15 mL of methanol, mix the three, stir at room temperature until completely dissolved, then add 0.50 g of sodium formate and stir until completely dissolved), place it in an 80 °C drying oven for reaction for 48 h, and then cool and take it out with the furnace.

[0037] Step S4: Sealing treatment 2. After rinsing the aluminum alloy substrate obtained in Step S3 with ethanol, immerse it in an emulsion containing 30% polytetrafluoroethylene by mass. After impregnation for 25 min, take it out and dry it at 280 °C for 30 min to obtain the aluminum alloy friction plate.

[0038] Example 4 The raw material is an aluminum, magnesium, silicon alloy, and the main component contents are: Si: 2%; Mg: 3%; the rest is basically aluminum, and other trace components are the same as 6061-T6.

[0039] The preparation steps are the same as those in Example 1.

[0040] Comparative Example 1 The raw material is a silicon aluminum alloy, and the rest is the same as in Example 1.

[0041] Comparative Example 2 Step S3: After washing the aluminum alloy substrate obtained in Step S2 with water, thoroughly clean its surface; and dry it at a temperature of 85 °C; then use a sandblasting machine to perform mechanical surface polishing on it to obtain the aluminum alloy friction plate.

[0042] The raw material is the same as in Example 1, and the rest of Step S1 and Step S2 are also the same as in Example 1.

[0043] Comparative Example 3 Obtain a paper-based friction plate through the preparation method of CN109837802B.

[0044] Performance test Performance test one: The oxide film thickness and hardness of the aluminum alloy friction plates in Examples 1-4 and Comparative Example 1 were detected. The hardness test method is as follows: The surface hardness of the anodized aluminum alloy was detected by the Vickers hardness method. A square conical diamond indenter was pressed into the surface of the specimen at an angle of 136° between the opposite faces. After maintaining for a certain time, the test load was removed, the diagonal length of the indentation was measured, and the hardness value was calculated.

[0045] The results are shown in Table 1: Specimen Thickness Hardness Example 1 55μm 680HV Example 2 54μm 670HV Example 3 54μm 675HV Example 4 46μm 613HV Comparative Example 1 36μm 550HV It can be seen from Table 1 that the hardness of the oxide film of the aluminum alloy friction plates made in Examples 1-3 can reach above 650 HV, which is significantly higher than that of Example 4 and much higher than that of Comparative Example 1, indicating that with the increase of silicon, the hardness of the oxide film on the surface of the aluminum alloy will decrease to a certain extent. In addition, the oxide film thickness of the aluminum alloy friction plates made in Examples 1-3 is uniform, the color quality is uniform, and the surface roughness Ra after treatment is 2.5-3.5, meeting the requirements of US Military Standard MIL-A-8625 Type III Class 1.

[0046] Performance Test Two: The aluminum alloy friction plates made in Examples 1-4 and Comparative Examples 1-2 were paired with themselves to form friction pairs, and the paper-based friction plate made in Comparative Example 3 was paired with a carbon steel counter-piece to form a friction pair, and the following performance tests were carried out respectively. The test results are shown in Tables 2-3.

[0047] Referring to the test conditions of the SAE NO.2 Friction Test Machine μPVT Test (Friction Coefficient - Pressure - Speed - Temperature Test), the friction and wear tests of the specimens were carried out under different pressure, speed, and temperature conditions. After completing the μPVT Test, the friction and wear tests of 1000 dynamic engagements were carried out under two energy density and specific pressure conditions. The friction and wear tests were divided into W1 and W2, and the test conditions are as follows: W1: Set the rotational speed at 2000 Rpm, the surface pressure at 3.00 MPa, the energy at 120 J / cm 2 , the cooling oil temperature at 80 °C, and carry out 1000 dynamic brakings. Measure the static friction coefficient once before and after the dynamic braking.

[0048] W2: Set the rotational speed at 2000 Rpm, the surface pressure at 8.0 MPa, the energy at 180 J / cm 2 , the cooling oil temperature at 80 °C, and carry out 1000 dynamic brakings. Measure the static friction coefficient once before and after the dynamic braking.

[0049] The static friction coefficients are shown in Table 2, and the wear records under W2 conditions are shown in Table 3.

[0050] Table 2 Table 3 Specimen Wear amount Example 1 0.002mm Example 2 0.000mm Example 3 0.000mm Example 4 0.005mm Comparative Example 1 0.015mm Comparative Example 2 0.029mm Comparative Example 3 0.043mm It can be seen from the performance test data table 2-3 that the friction plate of the present application can withstand greater energy and surface pressure, and under the same conditions, the friction plate of the present application has high wear resistance and is particularly suitable for use in the field of construction machinery.

[0051] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereby. Therefore, all equivalent implementations or changes made in accordance with the present application shall be covered within the protection scope of the present application.

Claims

1. An aluminum alloy friction plate, characterized in that, It includes aluminum alloy, hard anodized film layer and lubricating film layer.

2. The aluminum alloy friction plate according to claim 1, characterized in that, The aluminum alloy takes magnesium and silicon as main alloying elements and takes Mg2Si phase as the strengthening phase.

3. A kind of aluminum alloy friction plate according to claim 1, characterized in that The aluminum alloy contains the following components by weight percentage: Si 0.4 - 2%; Mg 0.8 - 3%; aluminum 94 - 99%.

4. A kind of aluminum alloy friction plate according to claim 1, characterized in that, The thickness of the hard anodized film layer is 45 - 55μm, and the hardness value ≥ 500HV.

5. A kind of aluminum alloy friction plate according to claim 1, characterized in that, The lubricating film layer is a polytetrafluoroethylene film.

6. A kind of aluminum alloy friction plate according to claim 1, characterized in that, The aluminum alloy friction plate further includes an intermediate layer, wherein the intermediate layer is between the hard anodized film layer and the lubricating film layer.

7. A kind of aluminum alloy friction plate according to claim 1, characterized in that, The intermediate layer is one or more of SiC or ZIF-8.

8. A brake friction pair, characterized in that, It is made of one or more pairs of aluminum alloy friction plates described in any one of claims 1 - 7.

9. A method for preparing an aluminum alloy friction plate as described in claims 1-5, characterized in that: It includes the following steps: Step S1, sandblast the surface of the aluminum alloy. Step S2, perform hard anodization on the aluminum alloy in the electrolyte of H2SO4 and oxalic acid solution to obtain an aluminum alloy substrate with a hard anodized film layer covering the entire surface. Step S3, after washing the aluminum alloy substrate in step S2 with water, immerse it for 15 - 30 min to form a lubricating film layer, take it out and dry it at 250 - 300°C for 20 - 40 min to obtain the aluminum alloy friction plate.

10. A preparation method of the aluminum alloy friction plate as described in claims 6-7, characterized in that: It includes the following steps: Step S1, sandblast the surface of the aluminum alloy. Step S2, perform hard anodization on the aluminum alloy in the electrolyte of H2SO4 and oxalic acid solution to obtain an aluminum alloy substrate with a hard anodized film layer covering the entire surface. Step S3, after washing the aluminum alloy substrate in step S2 with water, immerse it for 1 - 3 h to form an intermediate layer, evenly coat the intermediate layer on the hard anodized film, and take it out. Step S4, after rinsing the aluminum alloy substrate in step S3 with ethanol, immerse it in a polytetrafluoroethylene emulsion, take it out after 15 - 30 min of immersion and dry it at 250 - 300°C for 20 - 40 min to obtain the aluminum alloy friction plate.

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