Ni-Co/纳米ZrO_2复合材料的电化学行为及摩擦磨损性能

通过超声辅助电沉积的方法,在加入粒径为50nm的ZrO_2粉体的氨基磺酸盐镀液中制备了Ni-Co/纳米ZrO_2复合镀层。利用电化学方法(线性扫描伏安法、循环伏安法)对沉积动力学进行分析。通过XRD,SEM和EDS分别对复合镀层的微观结构、表面形貌和相组成等进行表征。同时,对镀层进行了纳米压痕测试和旋转摩擦测试。结果表明,Co~(2+)的电沉积行为遵循3D"成核/生长"机制,合金共沉积电位为-0.72V,复合共沉积电位为-0.70V。ZrO_2纳米粒子的加入降低了体系的极化度,使得电极过程更容易进行。纳米ZrO_2的添加量为15g/L时,镀层硬度、弹性模量以及硬模比分别为6.13GPa,291GPa和0.026;摩擦因数为0.3273,磨损量为0.55×10~(-5)g/m,分别为Ni/Co合金的3/4和1/2,超声和纳米粒子的协同作用能够明显改善镀层的力学性能。

Electrochemical Behavior and Friction and Wear Properties of Ni-Co/Nano ZrO2 Composites

Composite coatings consisting of a Ni-Co alloy matrix reinforced with ZrO2 particles(average size of 50nm)were synthesized by electrochemical deposition assisted by an external ultrasonicfield. The kinetics of electrodeposition was investigated using linear sweep voltammetry and cyclic voltam-metry.Scanning electron micrographs,X-ray diffraction and energy dispersive spectrum were em-ployed to characterize the morphology and composition of the coatings.Also in order to evaluate the mechanical properties of the coating nano-indentation and wear tests were conducted.The results indi-cated that the electro-crystallization of Co2+was governed by a three-dimensional"nucleation/growth"process.The electric potentials of co-deposition of alloy and composites are -0.72V and -0.70V re-spectively.The results show that polarizability of the composite system is smaller with the addition of ZrO2 particles and the ZrO2 improves the electrode process.when the addition of ZrO2 is 15g/L,coat-ing nanohardness,elastic modulus and the ratio of nanohardness to elastic modulus increase to 6. 13GPa,291GPa and 0.026 and friction coefficient and wear mass loss decrease to 0.3273 and 0.55× 10-5g/m,which is about 3/4 and 1/2 of Ni-Co alloy coating respectively.Results reveal that tribolog-ical properties of coating can be improved significantly by incorporating ZrO2 simultaneously with ul-trasonic.