Magnesium alloy surface conversion treatment liquid and treatment method thereof

Abstract

The invention relates to magnesium alloy surface conversion treatment liquid and a treatment method thereof. The magnesium alloy surface conversion treatment liquid comprises the following components of: 5 to 45 g / l of phytic acid, 0.1 to 3 g / l of calcium nitrate, 0.1 to 5 g / l of sodium tartrate and 0.1 to 3 g / l of ammonium metavanadate. The magnesium alloy surface conversion treatment method comprises the following steps of: performing mechanical pretreatment; deoiling and degreasing; performing acid washing; converting; and drying. The magnesium alloy surface conversion treatment liquid does not contain environmental pollution ingredients of chromium, fluorine and the like, the treatment method is simple and high in efficiency, and the compactness of film layers and the corrosion resistance and adhesive force of magnesium alloy organic coatings can be improved. The magnesium alloy surface conversion treatment liquid can be widely applied to the surface coating pretreatment of magnesium alloy castings, section bars and magnesium alloy products.

Description

technical field [0001] The invention relates to a surface conversion treatment liquid and a treatment method thereof, in particular to a magnesium alloy conversion treatment liquid and a conversion treatment method. Background technique [0002] Magnesium alloy has the characteristics of high specific strength and specific stiffness, good casting performance, excellent electrical shielding and damping performance, and recyclability. It is widely used in aerospace, automobiles and motorcycles, tools, electronic communications, optical instruments, computer manufacturing, etc. field. Since the electrode potential of the magnesium alloy is extremely negative (-2.36V), and the volume ratio of the natural oxide film to the metal itself is less than 1, it is not enough to protect the magnesium alloy matrix, and its corrosion resistance is poor. In order to improve the corrosion resistance of the magnesium alloy surface, many protective treatment methods have been developed, such ...

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Problems solved by technology

[0006] In addition, the phosphate conversion coating commonly used on magnesium alloys has better corrosion resistance and is a good coating primer, but the conversion coating is prone to wide cracks and coarse grains.

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