Annealed Crystallization and Catalytic activity of Ultrafine NiB Amorphous Alloy

• 作者: HUTiandou WEIShiqing
• 来源期刊: 北京同步辐射装置：英文版
• 学科: 工学
• 关键词: 非晶合金 NIB 催化激活 退火结晶
• 年，卷（期）: 2001,（1）
• 页码范围: 57-60
• 页数: 4页
• 分类号: TG146.15

摘要

A Ultrafine amorphous NiB alloy was prepared via chemical reduction method;Its structures during the crystallizatioin precess was characterized by such techniques as Differential thermal analysis (DTA),X-ray absorption fine structure (XAFS) and X-ray diffraction(XRD),and correlated to the catalytic properties for benzene hydrogenation.It was found that the crystallization of amorphous NiB alloy was carried out in two steps,as indicated by two exothermic peaks centered at 598 and 652K respectively.During the first step.two metastable crystalline phases,i.e.,Ni3B and a noaocrstalline Ni phase(Ni-rich NiB alloy),were formed.Further annealing at higher temperature of 652 K may result in the decomposition of crystalline Ni3B and aggregation of nanocrystalline Ni,the benzene hydrogenation is optimized around the annealing temperature of 623K.It most probably results from the maximum amount of active site on nanocrystalline Ni formed by thermal treatment at appropriate annealing temperature.