中文摘要：

通过正交试验对45钢上复合化学镀Ni-P—Al2O3的工艺条件进行优化，得到的最佳工艺条件为：NiSO4·7H2O25g／L，Nail2PO2·H2O30g／L，CH3COONa15g／L，NaF0．4g／L，乳酸20mL／L，硫脲20mg／L，十二烷基磺酸钠0．1g／L，纳米α-Al2O35g／L，温度90℃，pH4．8，时间2h，转速300r／min。分别采用扫描电镜、能谱仪、维氏硬度仪和电化学工作站对镀层的微观形貌、组成、显微硬度以及耐蚀性进行表征。在最优工艺下制备的Ni-P—Al2O3复合镀层，Al2O3微粒分布均匀，结构致密，显微硬度为204HV，耐蚀性均优于Ni-P镀层。

英文摘要：

The process conditions of electroless Ni-P-Al2O3 composite plating on 45 steel were optimized through orthogonal test. The optimal process conditions are as follows： NiSO4＂7H20 25 g/L, NaHEPOE＇H20 30 g/L, CH3COONa 15 g/L, NaF 0.4 g/L, lactic acid 20 mL/L, thiourea 20 mg/L, sodium dodecyl sulfate 0.1 g/L,α-Al2O3 nanoparticle 5 g/L, temperature 90 ℃, pH 4.8, rotation speed 300 r/min, and time 2 h. The micromorphology, composition, microhardness, and corrosion resistance of Ni-P-A1203 composite coating were characterized using scanning electron microscope, energy-dispersive spectroscope, Vikers hardness tester, and electrochemical workstation. The Ni-P-A1203 composite coating prepared under the optimal process conditions futures uniform distribution of A1203 particles and compact structure, and has a microhardness of 204 HV and better corrosion resistance than that of NiP coating.