Preparation method for metal surface corrosion resistant/radiating/electromagnetic shielding composite coating

Abstract

The invention discloses a preparation method for a metal surface corrosion resistant / radiating / electromagnetic shielding composite coating. The preparation method comprises the following steps: first, preparing a corrosion resistant and high thermal conductive bottom layer on the surface of a metal shell of a power component by adopting a nano-Al2O3 modified micro-arc oxidation technology; coating the micro-arc oxidation bottom layer with a graphene oxide dispersing liquid which is prepared by an improved Hummers method to obtain a preset graphene oxide layer; then, reducing the graphene oxide layer which is preset on the micro-arc oxidation bottom layer by using vitamin C to obtain an micro-arc oxidation / graphite composite coating for the surface of the metal shell of the power component. The composite coating prepared by the method has excellent performance: the salt-fog resistance is greater than 1,500 hours; the thermal conductivity is high; the emissivity is greater than 0.8; the radiating and cooling effect reaches 10 to 20 percent; the static contact angle is greater than 120 degrees; the electromagnetic shielding effect is greater than 50 dB. According to the preparation method, the problems that the metal (namely, an aluminium, magnesium and titanium alloy and a composite material thereof) shell of the power component used in marine climate and environment is poor in corrosion resistance and low radiating efficiency in a service process are solved.

Description

technical field [0001] The invention belongs to the technical field of preparation methods of metal surface anti-corrosion / heat dissipation / electromagnetic shielding composite coatings, and in particular relates to a preparation method of metal surface anti-corrosion / heat dissipation / electromagnetic shielding composite coatings. Background technique [0002] Power component housings used in marine climate environments require excellent corrosion resistance, excellent heat dissipation (conduction and radiation) performance and high electrical conductivity (electromagnetic shielding) during service. However, the corrosion resistance of power component metals (aluminum, magnesium, titanium alloys and their composite materials) is far from meeting the service conditions; at the same time, the efficiency of a single conduction cooling method for metal shells of components is extremely limited, while metal shells (such as aluminum, Magnesium and titanium alloys) have very low radi...

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Problems solved by technology

The application publication number is CN105491788A, the application publication date is April 13, 2016, and the invention patent application titled "a graphene heat dissipation shielding film and its preparation method", the patent is to prepare a carrier film layer on a flexible printed circuit board , ink layer, graphene heat dissipation layer, and conductive adhesive layer to achieve heat dissipation and electronic shielding, but the coating structure prepared by this method is cumbersome, the process is complicated, and there is a large interface heat between layers. resistance, which seriously affects the heat dissipation efficiency of the coating, and the adhesive used in this method is an organic binder, and the emissivity of the prepared coating is low, and the thermal stability and bonding force are not very ideal.

The application publication number is CN105039981A, the application publication date is November 11, 2015, and the name is "a method for improving the performance of lamp radiators". The patent prepares a heat dissipation composite coating by preparing micro-arc oxidation and spraying graphene. The method Use a water-based solvent for spraying graphene, but the composition of the water-based solvent is not clearly given, and the dispersion of graphene in the solvent is poor, and it is easy to agglomerate, which will greatly weaken the thermal conductivity and electrical conductivity of graphene; and the The graphene layer prepared by the method needs to be cured at 140-160°C, which will introduce thermal stress, weaken the bonding performance of the micro-arc oxidation coating, and at the same time have a corrosion effect on the micro-arc oxidation coating.

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