纳米晶低钼高铁Fe-Ni-Mo合金的制备及其微观结构

在酸性柠檬酸盐镀液中电沉积制备低Mo高Fe含量的Fe-Ni—Mo合金；采用扫描电镜、X射线衍射仪和X射线能谱仪对镀层微观结构、表面形貌及组成进行分析。结果表明：工艺条件和钼酸钠浓度对合金组成的影响较大;所得合金晶粒尺寸为6．2～12．7nm，并随电流密度、温度和电镀液的pH值的改变而变化；合金的晶体生长符合晶核三维生长模型，镀层表面形貌由平行和垂直于基体的生长速度的相对大小决定；镀层物相为固溶体和金属间化合物的多相结构，当电流密度为3A／dm^2时，镀层物相由FeNi（BCC）和FeMo固溶相转化为FeNi（FCC）和MoNi4多相结构；镀层的应力随晶粒尺寸的减小呈线性增大；合金镀层的点阵常数发生了畸变。

Preparation and microstructure of nanocrystalline Fe-Ni-Mo alloy with low Mo and high Fe content

Nanocrystalline Fe-Ni-Mo alloy with low Mo and high Fe content was electrodeposited from acid citrate electrolyte.The surface morphology,microstructure and composition of the alloys were analyzed by scanning electron microscopy,X-ray diffactometry and energy dispersive spectrometry.The results show that the technical parameters and the concentration of sodium molybdate have obvious effect on the composition of the alloy.The crystal grain size is from 6.2 to 12.7 nm and changes with current density,temperature and the pH value of the electrolyte.The crystalline growth of the alloy accords with the model of three-dimensional growth.The surface morphology is mainly determined by the rate competitions between the growing direction of vertical surface and the expanding direction along the surface towards circumambient.The results of the X-ray data show the presence of the multiphase containing solid solution and intermetallic compound in the deposits.The deposit phases alter from the FeNi(BCC) and FeMo solid solution to the FeNi(FCC) and MoNi_4 structure at 3 A/dm~2.The deposits internal stress increases linearly with the decrease of the grain size.The lattice parameter of the deposits are slightly distorted because of the residual stress in the deposits.