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选择铸态和挤压态AZ61镁合金,采用SEM、XRD和电化学测试等分析手段,研究在120℃和1.8 MPa的NaCl气氛中镁合金的腐蚀形貌和腐蚀机理。结果表明,在NaCl气氛、温度、压力和合金组织状态等多因素耦合作用下,由于β相重新分布以及晶粒尺寸变小,使得挤压态AZ61镁合金的腐蚀速率大于铸态的腐蚀速率,但腐蚀产物均以Mg(OH)2为主。较高的温度与NaCl气氛共同作用是加快镁合金腐蚀的主要原因。
The as-cast and as-extruded AZ61 magnesium alloys were selected. The corrosion morphology and corrosion mechanism of magnesium alloy in NaCl atmosphere at 120 ℃ and 1.8 MPa were studied by means of SEM, XRD and electrochemical tests. The results show that the corrosion rate of extruded AZ61 magnesium alloy is larger than that of as-cast corrosion due to the redistribution of β phase and the decrease of grain size due to the multi-factor coupling effect of NaCl atmosphere, temperature, pressure and alloy microstructure. However, the corrosion products are dominated by Mg (OH) 2. The higher temperature combined with the NaCl atmosphere is the main reason to accelerate the corrosion of magnesium alloy.