稀土元素由于良好的物理、化学、电、磁和光学性能，已经成功地应用在电镀、热镀锌、转化膜及化学热处理等表面处理方法中。非晶态合金镀层由于其结构的特殊性，使其具备了很好的综合物理和化学性能，从而引起了人们的高度重视。梯度功能材料(FGM)是应现代工业的高功能要求而发展起来的全新型未来材料之一，其内部成分和结构的相容性可有效地提高镀层与基体间的结合强度，改善耐蚀耐磨性。 本文以LY12硬铝合金为基体，采用化学镀的方法，选取不同的稀土元素作为添加剂，制备了Ni-P非晶态合金镀层。采用扫描电镜(SEM)、能谱(EDS)、X射线衍射(XRD)、显微硬度、腐蚀试验等检测手段，分析了稀土元素及稀土含量对非晶态合金镀层成分、微观结构、硬度及耐蚀性能的影响。 实验结果表明：稀土的添加可以提高镀层中P的含量以及镀层的非晶化程度，实现了提高镀层硬度和耐蚀性能的目的。其中添加0.15g/L稀土Y(NO3)3获得的镀层综合性能最好，镀层中P的含量达到12.76%，显微硬度高达641HV，镀层在中性、酸性和碱性环境下均表现出良好的耐蚀性。 其次，在Ni-P非晶态合金镀层的基础上，利用功能梯度材料的设计思路，通过改变合金镀层中P元素的含量，实现涂层内部结构逐渐由晶态、晶态+非晶态向非晶态的梯度变化，获得Ni-P合金梯度镀层。试验结果表明：Ni-P梯度镀层与铝合金基体结合良好，且在中性、酸性和碱性环境中，耐蚀能力均优于Ni-P非晶态合金镀层。

The rare earth element has successfully been applied in surface treating techniques such as electroplating, hot galvanization, conversion film and heat-treatment. Amorphous alloy coating has attracted great interest owing to its favorable physical and chemical properties. As one of the promising materials, functionally graded materials(FGM) have been developed under the high requirement of modern industry. In addition, the adhesive strength between coating and substrate as well as the corrosion resistance of the coatings can be improved efficiently by its component and structure compatibility. Employing chemical plating method, amorphous Ni-P alloy coating using the different types of rare earth as additives is prepared using the LY12 alloy as substrate in this paper. The influence of different type and content of rare earth on the composition, microstructure, micro-hardness and corrosion resistance of Ni-P amorphous alloy coatings were analysed by means of SEM, EDS, XRD and orther instruments. The results show that the microhardness and corrosion resistance of Ni-P coating are improved by adding the rare earth which can be able to increase the content of total phosphorus in the coating and enhance the extent of amorphization. The comprehensive property of Ni-P coating with 0.15g/L Y(NO3)3 rare earth is the best. The microhardness is 641HV and the corrosion resistances of Ni-P coating in neutral, acidic and alkaline solutions are excellent. In addition, Ni-P alloy gradient coating was prepared. The internal structure of Ni-P alloy gradient coating was changed from crystalline to crystalline and amorphous and then to amorphous by means of altering the P content. The results show that the cohesion between the coating and substrate and the corrosion resistances of Ni-P gradient plating is better than that of the amorphous Ni-P alloy coating in neutral, acidic and alkaline solutions.