图1a–h描绘了在不同间隔下浸入AP中的纯锌的SEM图像。对于放大的形态（图1a1–h1），选择点1–24进行EDS表征。浸入0.5 d后可清楚地观察到晶界（图1a），结果随着时间的推移晶界更加明显（图1b-f）。据报道，具有高能的晶界是引发腐蚀和蛋白质吸附的首选位置。0.5 d时，分散的黑色聚集体也会出现在表面上，并变成几乎覆盖表面的凝胶状薄膜（图1b）。然后，随着浸入时间的延长，许多扁圆形的物质随机出现在表面上（图1c–f）。同时，浸入21 d后晶界变得模糊（图1g），浸泡28 d后晶界几乎消失（图1h）。

Fig. 1a–h portray SEM images of pure Zn immersed in AP for various intervals. In the case of magnified morphologies (Fig. 1a1–h1), points 1–24 are selected for EDS characterization. Grain boundaries are clearly observed on the surface after 0.5 d immersion (Fig. 1a) and turn out to be more pronounced with time (Fig. 1b–f). It has been reported that the grain boundaries with high-energy are preferred sites for corrosion initiation and proteins adsorption. Scattered black aggregations also show up on the surface on 0.5 d and change into gel-like films that almost cover the surface (Fig. 1b). Then a number of oblate substances randomly appear on the surfaces with the extension of immersion time (Fig. 1c–f). Meanwhile, the grain boundaries become to be indistinct for 21 d immersion (Fig. 1g), and even almost disappear after soaking for 28 d (Fig. 1h).