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采用失重法、极化曲线、电化学阻抗谱和腐蚀形貌等方法研究了微量Sb对Mg-5A1-2Sr合金在3.5 mass%NaCl中性水溶液中耐腐蚀性能的影响。结果表明,Mg-5Al-2Sr-xSb(x=0,0.3,0.6,1.0)合金在3.5mass%NaCl中性水溶液中初期的腐蚀类型为点蚀,点蚀源于块状三元T相和颗粒状SbSr_2相。这些相的数量越多,尺寸越大,合金的腐蚀愈严重。网状分布的A1_4Sr相能够成为合金腐蚀的有效障碍。Mg-5Al-2Sr合金中加入0.3%Sb不仅能够有效地细化α-Mg基体组织,同时促进了Al_4Sr相的形成,使该相的分布更趋网状化,该合金的自腐蚀电位明显正移,腐蚀电流密度减小,腐蚀速率降低,合金的耐蚀性能提高。
The effects of trace Sb on the corrosion resistance of Mg-5A1-2Sr alloy in 3.5 mass% NaCl neutral aqueous solution were studied by weight loss method, polarization curve, electrochemical impedance spectroscopy and corrosion morphology. The results show that the initial corrosion type of Mg-5Al-2Sr-xSb (x = 0,0.3,0.6,1.0) alloy in 3.5mass% NaCl neutral aqueous solution is pitting corrosion, pitting originates from bulk ternary T phase and Granular SbSr_2 phase. The more the number of these phases, the larger the size, the more severe the corrosion of the alloy. The reticularly distributed A1_4Sr phase can be an effective barrier to corrosion of alloys. The addition of 0.3% Sb to Mg-5Al-2Sr alloy not only can effectively refine the α-Mg matrix, but also promote the formation of Al 4 Sr phase and make the distribution of the phase more network. The self-corrosion potential of the alloy is obviously positive The corrosion current density decreases, the corrosion rate decreases, and the corrosion resistance of the alloy improves.