Magnesium alloy passivation solution and magnesium alloy surface treatment method

Abstract

The invention relates to a magnesium alloy passivation solution and a magnesium alloy surface treatment method. The magnesium alloy passivation solution comprises the following components according to concentration: 1-4g / L chromium nitrate; 0.5-2g / L oxalic acid; 0.2-1g / L citric acid; 0.5-2g / L sodium silicate; and 0.2-1g / L cobalt nitrate. The surface treatment method comprises the steps of: putting magnesium alloy in a degreasing solution to undergo degreasing so as to remove surface greasy dirt; washing the degreased magnesium alloy and putting it into the magnesium alloy passivation solution to perform a passivation treatment; and washing the passivated magnesium alloy, and conducting an electrophoresis treatment. The magnesium alloy passivation solution and the magnesium alloy surface treatment method provided in the invention have the advantages that: the passivation solution does not contain hexavalent chromium and is in line with the environmental requirements; a passivation film is formed on the product surface, thus effectively preventing electrophoretic paint from corroding the magnesium alloy during electrophoresis; the passivation film has low resistance and does not affect the electrophoresis conductivity; the method adopts an intermediate temperature environment and has low energy consumption; and the passivation film is colorless and transparent, thus having no appearance influence on subsequent colorless electrophoresis.

Description

【Technical field】

[0001] The invention relates to a passivation solution and a surface treatment method, in particular to a magnesium alloy passivation solution and a magnesium alloy surface treatment method. 【Background technique】

[0002] Because magnesium alloy material is a light structural material, the quality is 2 / 3 of aluminum and 1 / 4 of steel. Compared with steel, aluminum, plastic and other engineering materials, magnesium alloy has good strength and rigidity, and good electromagnetic shielding performance , non-magnetic; good shock absorption; non-toxic, recyclable; excellent machining performance, high die-casting productivity, small size shrinkage, and has excellent low temperature performance and high thermal conductivity, so it is widely used. At present, it has become the main material in electronic products such as notebook computers, mobile phones, PDAs, etc., and the application range of magnesium alloys has rapidly expanded.

[0003] Magnesium alloy colo...

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