中文摘要：

采用复合镀渗工艺在316L不锈钢表面分别制备了两种纳米颗粒（非晶nano-SiO2颗粒和nano-SiC颗粒）增强的Ni基复合镀渗合金层.利用扫描电子显微镜（SEM）和透射电子显微镜（TEM）观察了两种复合镀渗合金层的微观组织特征.通过外加电位（＋0.2V）条件下的电流密度、冲蚀条件下的极化曲线和冲蚀后的交流阻抗谱表征了这两种复合镀渗层在单相流（3.5%（w,质量分数）NaCl溶液）与料浆流（3.5%NaCl＋10%（w）石英砂）中的电化学腐蚀特征,并采用SEM观察两种复合镀渗层冲蚀后的截面形貌,探讨这两种纳米颗粒增强的Ni基复合镀渗层在料浆流中的冲蚀机理.电化学测试结果表明：静态条件下,电刷镀含纳米SiO2颗粒的复合镀渗层的耐蚀性能低于单一合金层,而动态冲蚀条件下,结果与之相反;电刷镀含SiC颗粒的复合镀渗层的耐蚀性能在静态和动态冲蚀条件下均低于单一合金层.对两种复合镀渗层的冲蚀截面形貌观察表明：弥散分布的纳米SiO2颗粒能明显改善Ni基合金层的耐冲蚀性能;而添加纳米SiC颗粒在渗金属过程中已完全分解,导致三元硅化物（Cr6.5Ni2.5Si）和碳化物（Cr23C6）的析出,而析出相在冲蚀过程易于脱落,加速了Ni基合金层的质量流失．

英文摘要：

A nanoparticle reinforced Ni-based alloying layer was prepared by a duplex surface treatment on the surface of AISI 316L stainless steel. This steel contained Ni/nano-SiO2 or Ni/nano-SiC layer which was predeposited by brush plating and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructures of the two kinds of nanoparticles that reinforced the Ni-based alloying layers were investigated by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The corrosion behaviors of the composite layers under hydrodynamic conditions and at different rotational speeds were characterized by current responses at a potential of ＋0.2 V, a potentiodynamic polarization curve and electrochemical impedance spectroscopy （EIS） under a static state （3.5%（w, mass fraction） NaCl solution） and under slurry flow conditions （3.5%（w） NaCl solution＋10%（w） sand particles）. To assess possible erosion-corrosion mechanisms, the worn sample surfaces were observed by SEM. Electrochemical tests showed that the corrosion resistance of the composite layer with the brush plated Ni/nano-SiO2 particle interlayer was slightly lower than that of the single Ni-based alloying layer produced under static state conditions. However, under hydrodynamic conditions, the corrosion resistance of the composite layer with the brush plated Ni/nano-SiO2 particle interlayer was obviously superior to that of the single Ni-based alloying layer. The corrosion resistance of the composite layer produced with the brush plated Ni/nano-SiC particle interlayer was lower than that of the single Ni-based alloying layer produced under static state and hydrodynamic conditions. From the eroded-corroded cross-section morphologies we found that highly dispersive nano-SiO2 particles were helpful in improving the erosion-corrosion resistance of the Ni-based alloying layer whereas the carbides and silicide phases were deleterious to the Ni-based alloying layer.