Influences of ultrasonic irradiation on the morphology and structure of nanoporous Co nanoparticles during chemical dealloying

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• 作者：Hui Li ; Mu Zhu ; Yu Pang ; Huanhuan Du ; Tong Liu ; ^{tongliu@buaa.edu.cn}
• 关键词：Nanoporous nanoparticles ; Co ; Ultrasonic irradiation ; Chemical dealloying ; Microstructure
• 刊名：Progress in Natural Science: Materials International
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：26
• 期：6
• 页码：562-566
• 全文大小：2233 K
• 卷排序：26

文摘

The Co-61.8 wt% Al nanoparticles of 45 nm were prepared by hydrogen plasma-metal reaction (HPMR) method. The nanoparticles display core shell structure with Al13Co4 and CoAl core and aluminum oxide shell (about 2 nm). Under ultrasonic irradiation, nanoporous fcc-Co nanoparticles were produced successfully by chemically dealloying the Co-Al nanoparticles at room temperature, whereas, without ultrasonic irradiation CoAl phase could hardly react with sodium hydroxide solution. At 323 K the Co-Al nanoparticles could be dealloyed to fcc-Co and hcp-Co phases even without ultrasonic irradiation. The surface area of the dealloyed nanoparticles under ultrasonic irradiation was larger than that of the dealloyed sample without ultrasonic irradiation at the same temperature. It is believed that the microjet and shock-wave induced by ultrasonic irradiation give rise to particles size reduction, interparticle collision and surface cleaning, and accelerate the dealloying process and the phase transformation.