如图6(a)和(d)所示，浸泡5天后表面形成厚度为0.2μm的模糊薄层。然后浸泡15天和30天后(图6(b–d)) 厚度上升到0.25μm和0.33μm。根据图6中的线性能谱扫描剖面，腐蚀层由碳、氧、磷、钙和锌组成，与表3中的结果一致。

As shown in Fig. 6(a) and (d), an obscure thin layer with a thickness of 0.2 ?m forms on the surface after immersion for 5 days. Then the thickness rises up to 0.25 ?m and 0.33 ?m after immersion for 15 and 30 days, respectively (Fig. 6(b–d)). According to linear EDS scanning profiles in Fig. 6, the corrosion layers consist of C, O, P, Ca and Zn, agreeing with the results in Table 3.