【摘要】：目的通過Mo-Mn無鉻轉(zhuǎn)化膜提高AZ91D鎂合金的表面耐蝕性。方法采用正交實驗法,研究不同濃度的NaMoO4和KMnO4以及溫度對轉(zhuǎn)化膜的影響。優(yōu)選實驗參數(shù)后,考察時間對轉(zhuǎn)化膜的影響。利用SEM及EDS研究轉(zhuǎn)化膜的微觀形貌及成分變化,測試轉(zhuǎn)化膜在3.5%NaCl溶液中的極化曲線和交流阻抗譜。結(jié)果當(dāng)NaMoO4和KMnO4的質(zhì)量濃度分別為10,6 g/L,pH=5,溫度為50℃,轉(zhuǎn)化時間為40 min時,轉(zhuǎn)化膜顏色較為均勻,微觀裂紋相對較少,自腐蝕電位比鎂基體大約提高0.075 V,自腐蝕電流密度比鎂基體降低近1個數(shù)量級。當(dāng)Na Mo O4和KMnO4的質(zhì)量濃度分別為20,8 g/L,pH=5,溫度為50℃,轉(zhuǎn)化時間為40 min時,轉(zhuǎn)化膜顏色最為均勻,微觀裂紋相對最少,自腐蝕電位比鎂基體提高大約0.047 V,自腐蝕電流密度比鎂基體降低2個數(shù)量級。交流阻抗譜圖顯示,后一種轉(zhuǎn)化膜試樣的極化電阻為1450.2Ω,而鎂基體的極化電阻為806.4Ω。結(jié)論 Mo-Mn無鉻轉(zhuǎn)化膜可以顯著提高AZ91D鎂合金的表面耐蝕性。
[Abstract]:Objective To improve the surface corrosion resistance of AZ91D magnesium alloy by Mo-Mn chromium-free conversion film. Methods The effects of NaMoO4 and KMnO4 at different concentrations and temperature on the conversion film were studied by orthogonal experiment. After the experimental parameters, the effect of time on the conversion film was investigated. The polarization curves and the AC impedance spectra of the conversion film in 3.5% NaCl solution were studied by means of SEM and EDS. The results show that when the mass concentration of NaMoO4 and KMnO4 is 10,6 g/ L, the pH is 5, the temperature is 50 鈩，

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