Electrolytic machining method of passivated metal surface porous microstructure

Abstract

The invention discloses an electrolytic machining method of a passivated metal surface porous microstructure. The method comprises the following steps that S1, an anodic polarization curve of a samplein an electrolyte solution is measured by adopting a dynamic potential scanning method, and a workpiece is a passivation metal and an alloy thereof; S2, the workpiece is electrically connected with the anode end of a power supply, and a platinum electrode is electrically connected with the cathode end of the power supply, S3, the workpiece and the platinum electrode are fixed in an electrolytic tank, the workpiece and the electrode head of the platinum electrode are immersed in the electrolyte solution, and the electrode head of a reference electrode is immersed in the electrolyte solution; and S4, power supply is conducted on the power supply, and the current density of the surface of the workpiece is controlled to be located in the current density interval of the transition area of theanode polarization curve of the sample. According to the method, occurrence of surface pitting of the workpiece is accelerated by controlling an external electric field, so that a large amount of holes are formed in the workpiece machining surface to form a porous workpiece surface, the process is simple, machining is not limited by the shape of the surface of the workpiece, and the method can beapplied to the surface machining of the workpiece which is formed in a complex manner, and is wide in application range.

Description

technical field [0001] The invention relates to the field of metal surface processing, in particular to an electrolytic processing method for passivating metal surface porous microstructures. Background technique [0002] Due to the action of metal and oxidizing substances, a very thin, dense, and well-covered passivation film is formed on the metal surface, which is firmly adsorbed on the metal surface. This film exists as a separate phase, usually a compound of metal oxides. It plays the role of completely separating the metal from the corrosive medium, preventing the metal from contacting the corrosive medium, so that the metal basically stops dissolving and forms a passive state to prevent corrosion. Passivation metal surfaces are prone to pinhole corrosion (that is, pitting corrosion) to form holes, which is a typical form of electrochemical localized corrosion. The research on surface pinhole corrosion mainly focuses on how to avoid the occurrence of corrosion. [0...

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Problems solved by technology

Both of the above two methods are carried out in the super passivation stage of the polarization curve, and need templates or shaped electrodes to realize surface porous structure processing. The application is limited due to the complex process, high cost, and inability to apply to complex-shaped surfaces.

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