Preparation method for inducing titanium or titanium alloy surface chemical conversion film by virtue of electric coupling

Abstract

The invention discloses a preparation method for inducing a titanium and titanium alloy surface chemical conversion film by virtue of electric coupling. The method comprises the following steps: coupling a pre-treated titanium and titanium alloy matrix with metals with relatively low corrosion potentials, wherein the titanium and titanium alloy matrix with a high self-corrosion potential is a cathode, and a magnesium alloy, pure iron and 35CrMnSi with low self-corrosion potentials are an anode; connecting the cathode with the anode in a manner of direct contact and conductive wire connection, and then placing the cathode and the anode in a chemical conversion solution; and carrying out chemical conversion at the room temperature to obtain the titanium and titanium alloy surface chemical conversion film. According to the method disclosed by the invention, the reaction can be completed at the room temperature, and the obtained film layer are fine and compact in grains, excellent in electrochemical performance, low in cost, high in film-forming speed and easy to operate. A titanium-based chemical conversion film with more excellent surface structure and mechanical property can be obtained through changing different coupling systems and cathode-anode area ratios.

Description

technical field [0001] The invention relates to the field of surface modification of metal materials, in particular to a method for preparing a chemical conversion film on the surface of titanium or titanium alloy induced by electric coupling. Background technique [0002] Titanium or titanium alloys have been more and more widely used in the national economy because of their advantages such as high specific strength, low density, non-magnetic properties, high temperature resistance, small thermal expansion coefficient and high corrosion resistance. However, titanium or titanium alloys also have disadvantages such as poor wear resistance, greatly reduced corrosion resistance in chloride-containing solutions and atmospheres, easy passivation, and poor coating adhesion, which limit their application range. In order to further improve its performance, it is often necessary to carry out surface treatment on titanium or titanium alloy. Phosphating is widely used in the surface m...

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Problems solved by technology

The process is complicated, the conversion temperature is high, and the reaction time is long

[0004] Literature (Zhao X, Xiao G, Zhang X, et al.Ultrasonic Induced Rapid Formation and Crystal Refinement of Chemical Conversed Hopeite Coating on Titanium[J].Journal of Physical Chemistry C,2014,118(4):1910-1918.) report An ultrasound-enhanced grain refinement of zinc phosphate on the titanium surface and its preparation method, although the method is simple to operate, but the application of the ultrasonic field will generate instantaneous high temperature and high pressure will make the bath unstable, easy to produce sediment, and reduce the chemical conversion liquid. Utilization of

[0005] Patent CN 103952745 A discloses a method for preparing a zinc phosphate chemical conversion film on a titanium surface. Although this method can prepare a zinc phosphate chemical conversion film on a pure titanium substrate, the method requires an electric current field to be Under the condition of high temperature, the chemical conversion base liquid is prone to flocculation and sedimentation, which reduces the concentration of each component in the chemical conversion liquid to varying degrees, reduces the film-forming efficiency of the chemical conversion film, and prolongs the life of the chemical conversion film. The time of film formation increases the cost, and the formed zinc phosphate conversion coating has large grains and a phenomenon of bare substrate

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