Influence of current density on nano-Al_2O_3/Ni+Co bionic gradient composite coatings by electrodeposition  

作　　者：Yan Liu Luquan Ren Sirong Yu Zhuwu Han 

机构地区：[1]The Key Laboratory of the Ministry of Education of China for Terrain-machine Bionics Engineering, Jilin University, Changchun 130022, China [2]College of Materials Science and Engineering, Jilin University, Changchun 130022, China

出　　处：《Journal of University of Science and Technology Beijing》2008年第5期633-637,共5页北京科技大学学报（英文版）

基　　金：the National Natural Science Foundation of China (No50635030);the National Basic Research of China (No2007CB616913);the Program for New Century Excellent Talents in University (2005)

摘　　要：Metal and nano-ceramic nanocomposite coatings were prepared on the gray cast iron surface by the electrodeposition method. The Ni-Co was used as the metal matrix,and nano-Al2O3 was chosen as the second-phase particulates. To avoid poor inter-face bonding and stress distribution,the gradient structure of biology materials was found as the model and therefore the gradient composite coating was prepared. The morphology of the composite coatings was flatter and the microstructure was denser than that of pure Ni-Co coatings. The composite coatings were prepared by different current densities,and the 2-D and 3-D morphologies of the surface coatings were observed. The result indicated that the 2-D structure became rougher and the 3-D surface density of apices became less when the current density was increased. The content of nanoparticulates reached a maximum value at the current density of 40mA·cm^-2,at the same time the properties including microhardness and wear-resistance were analyzed. The microhardness reached a maximum value and the wear volume was also less at the current density of 40mA·cm^-2. The reason was that nano-Al2O3 particles caused dispersive strengthening and grain refining.Metal and nano-ceramic nanocomposite coatings were prepared on the gray cast iron surface by the electrodeposition method. The Ni-Co was used as the metal matrix,and nano-Al2O3 was chosen as the second-phase particulates. To avoid poor inter-face bonding and stress distribution,the gradient structure of biology materials was found as the model and therefore the gradient composite coating was prepared. The morphology of the composite coatings was flatter and the microstructure was denser than that of pure Ni-Co coatings. The composite coatings were prepared by different current densities,and the 2-D and 3-D morphologies of the surface coatings were observed. The result indicated that the 2-D structure became rougher and the 3-D surface density of apices became less when the current density was increased. The content of nanoparticulates reached a maximum value at the current density of 40mA·cm^-2,at the same time the properties including microhardness and wear-resistance were analyzed. The microhardness reached a maximum value and the wear volume was also less at the current density of 40mA·cm^-2. The reason was that nano-Al2O3 particles caused dispersive strengthening and grain refining.

关 键 词：ELECTRODEPOSITION composite coating current density NANO-AL2O3 microstructure mechanical properties 

分 类 号：TN710[电子电信—电路与系统]