图为n-Al2O3/Ni-Co合金纳米复合电镀层与Ni-Co镀层的XRD图谱，其中（a）为Ni-Co镀层，（b）为n-Al2O3/Ni-Co纳米复合镀层。对比分析两种镀层的谱图可知，各衍射峰对应的晶面依次是（111）、（200）和（220），为面心立方，和纯镍的PDF卡接近。说明这两种镀层沉积过程中Co原子占据了Ni原子的位置，形成了固溶体，因此镀层的特征峰和面心立方镍的特征峰接近。

The figure shows the XRD patterns of n-Al2O3/Ni-Co alloy nanocomposite plating layer and Ni-Co plating layer, where (a) is Ni-Co plating and (b) is n-Al2O3/Ni-Co nanocomposite plating. Comparing the spectra of the two plated layers, it can be seen that the crystalline planes corresponding to each diffraction peak are (111), (200) and (220) in order, which are face-centered cubic and close to the PDF card of pure nickel. It indicates that the Co atoms occupy the position of Ni atoms during the deposition of these two plated layers and form solid solution, so the characteristic peaks of the plated layers are close to those of face-centered cubic nickel.