Method for increasing the corrosion resistance of aluminium components using laser treatment

Abstract

The present invention relates to a method for increasing the corrosion resistance of at least one surface area of ​​a component made of aluminum casting material, comprising a) the provision of a component made of aluminum casting material; b) the treatment of at least one surface area of ​​the component using a laser. The process is particularly advantageous for treating surface areas intended for sealing points or solid seals. The present invention also relates to corresponding components made of cast aluminum material, which have at least one surface area that has been treated by means of a laser. Furthermore, the present invention relates to the use of a laser, preferably a pulsed or Gaussian laser, in a method for increasing the corrosion resistance of components made of cast aluminum material.

Description

[0001] The present invention relates to a method for increasing the corrosion resistance of at least one surface area of ​​a component made of cast aluminum material, comprising (a) the provision of a component made of cast aluminium material; b) treating at least one surface area of ​​the component by means of a laser.

[0002] The present invention also relates to corresponding components made of cast aluminum material, which have at least one surface area that has been treated by means of a laser.

[0003] Furthermore, the present invention relates to the use of a laser, preferably a pulsed or Gaussian laser, in a method for increasing the corrosion resistance of components made of cast aluminum material.

[0004] Components made of cast aluminum are used in various fields of technology, including electrical machines. Examples include housings for electric vehicle drives or power electronics.

[0005] The aluminum alloys used must meet specific requirements, particularly with regard to mechanical properties, procurement costs, and corrosion resistance. In particular, the corresponding components must be cost-effective, exhibit a balanced mechanical profile, and simultaneously be resistant to corrosion. However, not all aluminum alloys exhibit sufficient corrosion resistance for their intended applications, so the corresponding aluminum alloys or the components made from them must undergo a suitable treatment to increase corrosion resistance, which further increases manufacturing effort and costs.

[0006] A corresponding aluminum alloy known in the prior art is, for example, the EN AC-46000 alloy, also known as EN AC-AlSi9Cu3(Fe) or Al 226. This alloy exhibits good mechanical properties, is easy to process, and is also economically attractive. However, due to its relatively poor corrosive properties, this alloy has only very limited use in housings for electric vehicle drives or power electronics. Its corrosion resistance is particularly inadequate for solid seals. Therefore, the corrosion resistance of such an alloy must be appropriately increased to ensure its suitability for the intended application.

[0007] Against this background, the object of the present invention is to provide a method with which the corrosion resistance of components made of cast aluminum material can be increased or improved in a simple manner.

[0008] These and other objects are achieved by the present invention.

[0009] Surprisingly, it was discovered that the sometimes complex treatment to increase corrosion resistance does not necessarily have to be performed on the entire component; rather, it is sufficient to apply this treatment to the surface areas of the component where, in practice, there is an increased risk of corrosion. It was also surprisingly discovered that this increase in corrosion resistance can be achieved through laser treatment.

[0010] Laser treatment treats the corresponding surface area of ​​the component, increasing or improving the corrosion resistance of the treated area. Laser treatment can, for example, remelt the surface. Undefined pre-oxidation on the surface can also be removed. Furthermore, a defined and / or homogeneous oxide layer can be created on the surface. Laser treatment can also create a favorable microstructure of the alloy on the surface.

[0011] The present invention particularly relates to a method for increasing the corrosion resistance of at least one surface area of ​​a component made of cast aluminum material.

[0012] The present invention relates to a method for increasing the corrosion resistance of at least one surface region of a component made of cast aluminum material, comprising a) providing a component made of cast aluminum material and b) treating at least one surface region of the component by means of a laser.

[0013] The process according to the invention therefore increases or improves the corrosion resistance of the treated surface area.

[0014] In the context of the present invention, increased corrosion resistance means that corrosion in the treated area occurs more slowly than in the untreated area. As a rule, the corrosion stage is correspondingly less advanced. This is usually already evident visually, but in any case, it can be determined by conventional surface analyses such as microscopic images and / or electrochemical or morphological examinations. Common methods are known to those skilled in the art. Another test criterion is seal penetration, which examines the extent to which corrosion progresses in the seal area.

[0015] Due to the increased corrosion resistance of the treated surface area, any corrosion of the treated surface area occurs significantly more slowly compared to the untreated component or the untreated component surface.

[0016] It has surprisingly been found that the treated surface area, which is preferably intended for a seal and in particular a solid seal, exhibits increased and improved corrosion resistance, and thus the corresponding seal or solid seal exhibits higher and improved sealing values. In the case of a surface area treated according to the invention, the seal's function is thus maintained for a longer period of time compared to a case without surface treatment. Without treatment, failure of the seal is to be expected within a short period of time, whereas treating the surface area of ​​the seal leads to increased corrosion resistance, and the seal therefore retains its function for a longer period of time.

[0017] Preferably, the method for increasing corrosion resistance relates to a surface area of ​​the component intended for a sealing point. In principle, any type of sealing point is suitable. Preferably, the method is intended for a sealing point for a solid seal. Corresponding seals are known to those skilled in the art.

[0018] In the method according to the invention, a component made of cast aluminum material is first provided (step a).

[0019] Preferably, the component to be treated consists essentially of cast aluminum material. Preferably, the component to be treated consists of at least 80 wt.%, preferably at least 85 wt.%, more preferably at least 90 wt.%, more preferably at least 95 wt.% cast aluminum material.

[0020] In a particular embodiment, the cast aluminum material comprises an aluminum alloy selected from EN AC-46000, EN AC-44300, EN AC-47100, or EN AC-43400. Particularly preferred is the aluminum alloy EN AC-46000, also referred to as EN AC-AlSi9Cu3(Fe) or Al 226. In a further embodiment, the component made of cast aluminum material comprises an aluminum alloy that meets the definition according to DIN EN 1706.

[0021] Particularly preferably, the aluminum casting material consists essentially of an aluminum alloy. Preferably, the aluminum casting material consists of at least 80 wt.%, preferably at least 85 wt.%, more preferably at least 90 wt.%, more preferably at least 95 wt.% of an aluminum alloy, preferably EN AC-46000, EN AC-44300, EN AC-47100, or EN AC-43400, especially preferably EN AC 46000.

[0022] EN AC-46000 is usually composed as follows in the casting alloy: 8.0-11 wt% Si, 1.3 wt% Fe, 2.0-4.0 wt% Cu, 0.55 wt% Mn, 0.05-0.55 wt% Mg, 0.15 wt% Cr, 0.55 wt% Ni, 1.2 wt% Zn, 0.29 wt% Pb, 0.15 wt% Sn, 0.25 wt% Ti, a maximum of 0.25 wt% impurities, and the remainder Al, with the wt% adding up to 100 wt% in the alloy.

[0023] More preferably, the component to be treated consists essentially of an aluminum alloy. Preferably, the component to be treated consists of at least 80 wt.%, preferably at least 80 wt.%, more preferably at least 90 wt.%, more preferably at least 95 wt.% of an aluminum alloy, preferably EN AC-46000, EN AC-44300, EN AC-47100, or EN AC-43400, especially preferably EN AC 46000.

[0024] Subsequently (step b), at least one surface area of ​​the component is treated with a laser. Suitable lasers are known to those skilled in the art.

[0025] In a preferred embodiment, the laser treatment is performed, for example, using a high-performance, diode-pumped solid-state laser. This can have a laser power (CW) of 100 to 600 watts, preferably 150, 300, 500, or 600 watts. A typical laser wavelength is, for example, 1064 nm. The processing speed can be freely selected depending on the laser. Typical processing speeds are preferably in the range of 50 to 2 cm2 / s.

[0026] Preferably, the treatment of at least one surface region of the component is carried out by a pulsed laser or a Gaussian laser.

[0027] Laser treatment advantageously removes undefined pre-oxidation on the surface and / or creates a defined and homogeneous oxide layer on the surface. Furthermore, it advantageously creates a structured surface, which, among other things, improves adhesion. Furthermore, it advantageously removes dirt and grease from the surface.

[0028] Thus, the method according to the invention preferably serves to prepare components made of cast aluminum material on an intended surface area for the use of seals, in particular solid seals.

[0029] The method according to the invention is particularly advantageous for increasing the corrosion resistance of components used as housings and which preferably have at least one surface area intended for a sealing point. Housings for electric drives, especially vehicle drives, are particularly preferred. Housings for power electronics are also preferred.

[0030] Furthermore, the method according to the invention is particularly suitable for producing a component having at least one surface region with increased corrosion resistance. Accordingly, the present invention further provides a method for producing a component having a surface region with increased corrosion resistance, wherein the surface region with increased corrosion resistance is obtainable by laser treatment.

[0031] The present invention further relates to components made of cast aluminum material with at least one laser-treated surface area with increased corrosion resistance. These components are preferably obtainable by the process described herein.

[0032] Preferably, the components made of cast aluminum material have been treated with the method described herein in at least one surface area with increased corrosion resistance.

[0033] The treated surface area of ​​the components made of cast aluminum material is preferably intended for a sealing point, in particular for a solid seal.

[0034] In a preferred embodiment, the components are housings, in particular housings for electric drives and vehicle drives as well as housings for line electronics.

[0035] A further object of the present invention is the use of a laser in a method for increasing the corrosion resistance of at least one surface area of ​​a component made of a cast aluminum material and the use of a laser for treating a component made of a cast aluminum material to increase the corrosion resistance.

[0036] Particularly preferred is the use of a pulsed or Gaussian laser in said method for increasing the corrosion resistance of at least one surface area of ​​a component made of a cast aluminum material. Examples of implementationExample 1 - Surface treatment

[0037] An aluminum cast component made of EN AC-46000 was manufactured using a pressure die-casting process. Some surface areas were subsequently treated with a pulsed laser with a power of 600 W and a wavelength of 1064 nm to increase corrosion resistance. Microscope images of the treated surfaces are shown in Fig. shown. Example 2 - Corrosion test

[0038] A cast aluminum component made of EN AC-46000 material, designed with a surface area for a solid seal, was manufactured using a die-casting process and machined. The corresponding surface area for the seal was then treated with a pulsed laser with an output of 600 W and a wavelength of 1064 nm to increase corrosion resistance. The component was then subjected to a corrosion test. The corrosion test simulates the stress the component is exposed to in salty air and water, as can occur in certain regions of the world and under winter road conditions. The corrosion test serves to protect the component against malfunction under salt exposure, e.g., due to short circuits and leakage currents caused by the penetration of liquid or salt into the component.

[0039] The corrosion test consists of four test cycles, each lasting two weeks, for a total of eight weeks. During each test cycle, the component is subjected to a one-week alternating climate program with temperatures up to 80 °C, as well as a one-week alternating corrosion climate program. The alternating corrosion climate program includes, among other things, a salt spray test according to DIN EN ISO 9227 NSS. For example, the alternating corrosion climate program also includes corrosion tests according to DIN EN ISO 6270 AHT and ISO 554.

[0040] The result is in Fig. It is clear that the surface area around the seal shows almost no corrosion, while the untreated surface of the component shows clear signs of corrosion. Fig. 1a: Microscope image (50x magnification) of a laser-treated surface (energy: 100 W). Fig. 1b: Microscope image (30x magnification) of a laser-treated surface (energy: 600 W). Fig. 2a and Fig. 2b: Component made of EN AC-46000 after corrosion testing. The part intended for the solid seal was laser-treated. The remaining surface of the component is untreated.

Claims

[1] Method for increasing the corrosion resistance of at least one surface area of ​​a component made of cast aluminum material, comprising (a) the provision of a component made of cast aluminium material; b) treating at least one surface area of ​​the component by means of a laser. [2] Method according to claim 1, wherein the treated surface area of ​​the component is intended for a sealing point, and preferably the sealing point is a sealing point for a solid seal. [3] Method according to one of claims 1 or 2, wherein the method is intended to increase the corrosion resistance at sealing points for solid seals on cast aluminum components. [4] Method according to one of claims 1 to 3, wherein the treatment of the component with a laser is carried out by a pulsed or Gaussian laser. [5] Method according to one of claims 1 to 4, wherein the component made of cast aluminum material comprises an aluminum alloy selected from EN AC-46000, EN AC-44300, EN AC-47100 and EN AC-43400, particularly preferably EN AC-46000. [6] Method according to one of claims 1 to 5, wherein the component made of cast aluminum material comprises an aluminum alloy which meets the definition according to DIN EN 1706. [7] Method according to one of claims 1 to 6, wherein the component made of cast aluminum material consists essentially of an aluminum alloy. [8] Method according to one of claims 1 to 7, wherein the component is a housing and preferably a housing for an electric vehicle drive or for line electronics. [9] Component made of cast aluminum material, which has at least one laser-treated surface area with increased corrosion resistance. [10] Component according to claim 9, wherein the surface region with increased corrosion resistance is obtainable by a method according to any one of claims 1 to 8. [11] Component according to claim 9 or 10, wherein the at least one laser-treated surface area with increased corrosion resistance is at a sealing point, preferably at a sealing point for a solid seal. [12] Component according to one of claims 9 to 11, which is a housing for an electric vehicle drive or for line electronics. [13] Use of a laser, preferably a pulsed or Gaussian laser, in a method for increasing the corrosion resistance of at least one surface area of ​​a component made of an aluminum cast material according to one of claims 1 to 8 and / or for treating a component according to one of claims 9 to 12.

Images