Mechanism and microstructure of nickel-ceria composite coatings prepared by pulse current deposition

• 作 者: ZHOU Xiaowei SHEN Yifu ZHENG Y
• 机 构: College of Materials Science and Technology,College of Mechanical Engineering
• 出 处: 稀土学报（英文版）
• 发表日期: 2004年期
• 关键词: ultrasonic field mechanism pulse current deposition microstructure orthogonal ex

In recent research,a novel method combined with pulse current (PC) deposition and the ultrasonic (U) field was used to fabricate pure nickel and nickel-ceria composite coatings,respectively.Morphology,crack propagation,and crystal texture were observed and analysed by using environment seanning electron microscopy (E-SEM) and transmission electron microscopy (TEM).Orthogonal experiment [L16 (45)] was designed to optimize the parameters of pulsed power and the appropriate amount of RE addition based on microhardness.Effect of RE addition and pulsed current on the mechanism of co-electrodeposition was also investigated and compared.Experimental results indicated that it produced the alloying coatings,exhibiting compact grain and amorphous state.Nano-sized RE would preferentially occupy and pad at the edge of cracked gaps and micropore to limit the growing location and space for coarse Ni grain.Furthermore,during annealing at 480 ℃ for 2 h,a solid-solution precipitated phase named NiCexO1-x (0＜x＜0.5) dispersed along the large crystal boundary,which would make RE diffused sufficiently to improve crack propagation resistance and promote densifieation efficiently.