Influence of pulse electrodeposition parameters on microhardness, grain size and surface morphology of Ni�?�Co/SiO$_2$ nanocomposite coating

Bulletin of materials science

SHIVA NAVAZANI²  ALI SHOKUHFAR²  REZVAN YAVARI¹  SIAVASH IMANIAN GHAZANLOU² 

[1] Faculty of Materials and Metallurgy Engineering, Semnan 35131-19111, Iran$$Faculty of Materials and Metallurgy Engineering, Semnan 35131-19111, IranFaculty of Materials and Metallurgy Engineering, Semnan 35131-19111, Iran$$;Advanced Materials and Nanotechnology Research Laboratory, Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran 1969764499, Iran$$Advanced Materials and Nanotechnology Research Laboratory, Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran 1969764499, IranAdvanced Materials and Nanotechnology Research Laboratory, Faculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran 1969764499, Iran$$

关键词: Nanocomposite coating;    electrodeposition;    average current density;    pulse frequency;    duty cycle.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

Ni�?�Co/SiO$_2$ nanocomposite coatings and Ni�?�Co alloy coatings were prepared on steel substrate using direct and pulse electrodeposition methods. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-raymap and energy dispersive X-ray spectroscopy (EDX) were employed to investigate the phase structure, surface morphology, and elemental analysis of coatings, respectively. In high discharge rates, the surface morphology was rough, disordered and gross globular; on the contrary, in the low rates, it was smoother, more ordered and fine globular. Also, effect of electrodeposition parameters such as average current density, pulse frequency and duty cycle on the microhardness and grain size of nanocomposite coatings that produced through the pulse current electrodeposition method have been investigated. By amplifying both duty cycles up to 50% and average currentdensity from 2 to 6 A dm$^{�?2}$, microhardness increased, while the grain size decreased. But when duty cycle mounted on more than 50% and the average current density went up to 8 A dm$^{�?2}$, microhardness lessened, while the grain size rose. The optimum value for pulse frequency was about 25 Hz. Results showed that microhardness of nanocomposite coatings which were produced by pulse current method was higher than that of produced by direct currentmethod.

【 授权许可】

Unknown