纳米金刚石/镍复合电刷镀层的显微结构研究

Study on microstructure of electric brush plated nano-diamond/Ni composite coating

对以45#钢为基底的纳米金刚石/镍复合镀层和普通快速镍镀层的表面进行了研究。扫描电镜分析结果表明,纳米金刚石/镍复合镀层表面成典型的"菜花头"形状,弥散分布的纳米金刚石被镍包裹。由于部分纳米金刚石颗粒可视为镍原子非自发形核的基底,能够吸引更多的镍离子沉积成核,提供大量的结晶生长点,达到细化晶粒的效果,因此与普通快速镍层相比,复合镀层的表面更加平整、致密,组织更加细化。X射线衍射分析结果进一步证明,随着纳米金刚石加入量的增加,镀层表面晶粒尺寸逐渐减小。并据此提出纳米金刚石-镍电刷镀复合镀层的生长过程物理模型。

The surface morphologies of 45# steel-based composite with nano-diamond/Ni electro brush-plating and general Ni composite coating were studied. By scanning electron microscopy analyzing, the results showed that the surface of nano-diamond/Ni electro brush-plating is typical ＂cauliflower＂ morphology and the nano-diamond particles are enwrapped by the dispersive nickel grains. Because the partial nano-diamond particles can regard as the non-spontaneous nucleation base of the nickel atom and can attract more nickel ion to deposit and nucleate, then them offer a great deal of crystallization growth point so as to achieve the refined grain effect. Therefore, comparing with the general Ni composite coating, the surface of nano-diamond/Ni electro brush-plating is more smooth and compact, and the crystal structure is finer. The results of X-ray diffraction further proofed that the grain sizes of composite coating gradually become smaller with the content of nano-diamond increasing. Further, the physical model of growth process on nano-diamond/Ni electro brush-plating was built according to the experimental result.