图是硬度值在镀层不同位置的变化趋势，由图可知，靠近基体部分的镀层硬度最大，为1180HV。随着镀层的增厚，镀层硬度有所下降，分析认为，刚开始生产时，镀液温度较低，镀层沉积速度慢，镀层的组织比较致密，此时沉积镀层的硬度较高，随着刷镀的进行，镀液的温度升高，电流密度增大，镀层沉积速度增大，组织略有变差，硬度值有所下降。

图

The graph shows the trend of hardness value in different positions of the plating layer, from the graph, it can be seen that the hardness of the plating layer near the substrate is the largest, 1180 HV. With the thickening of the plating layer, the hardness of the plating layer decreases, and the analysis shows that at the beginning of production, the temperature of the plating solution is low, the deposition speed of the plating layer is slow, the organization of the plating layer is relatively dense, and the hardness of the deposited layer is higher at this time. As the current density increases, the deposition speed increases, the organization becomes slightly worse, and the hardness value decreases.

Figure