中文摘要：

通过电镀法制备了功能梯度Ni—P合金镀层：SEM形貌照片显示，梯度层截面致密、无明显的宏观界面；400℃热处理前后梯度层中P含量分布曲线表明，从界面到镀层表面，P含量逐渐降低，呈现明显的梯度变化。在质量分数分别为10％的盐酸和氢氧化钠介质中的动电位极化曲线和电化学交流阻抗谱分析、含氯酸性介质中的腐蚀前后的表面形貌照片表明，与硬铬镀层相比，经过400℃热处理后的梯度Ni—P合金镀层的腐蚀电位提高了600mV以上，腐蚀电流分别降低了2个和1个数量级，阻抗值亦明显提高，而且，其腐蚀前无裂纹，腐蚀后仅发生轻微的点蚀现象。梯度Ni—P合金镀层较硬铬镀层表现出更优异的耐蚀性能。

英文摘要：

The function gradient Ni-P alloy deposit was prepared by plating. SEM morphology photo reveals that the section of gradient layer is dense and no evident macrointerface can be seen. P contribution curves before and after heat treatment at a temperature of 400℃ show that the contents of P decrease gradually and present evident gradient variation from interface to surface of deposit. Analysis of potentidynamic polarization curves and electrochemical impedance spectroscopy in the media of mass fraction of 10% hydrochloric acid and sodium hydroxide respectively, and the surface morphology photos before and after corrosion in acid media containing chloride show that, compared with hard chromium deposit, the corrosion potential of gradient Ni-P alloy deposit is increased by more than 600 mV after heat treatment at 400 ℃. Corrosion current decrease by 2 and 1 orders of magnitude respectively. Impedance values increase markedly. Futhurmore, there is no crack before corrosion and slight spot corrosion takes place after corrosion. The gradient Ni-P alloy deposit presents better corrosion resist- ance than that of the hard chromium deposit.