X.G
,
Yang
,
Q.A. Zhang
,
K. Y Shu
,
YL. Du
,
YQ. Lei and Q.D. Wang (Department of Materials Science and Engineering
,
Zhejiang University
,
Hangzhou 310027
,
China )W.K. Zhang(Department of Applied Chemistry
,
Zhejiang University of Technology
,
Hangzhou 3100l4
,
China )G.L. Lu(Central Lab
,
Zhejiang University
,
Hangzhou 310028
,
China)
金属学报(英文版)
The annealing treatment was found to improve the cyclic stability but to degmde discharpe capacity, activation and high-rate discharpeability for the Ti-substituted AB2type alloy electrode. A larper polarization was found in the annealed alloy because of its poor discharpe kinetics resulted hem the structural homogeneity. At larae discharpe cumnts, the hydmpen dchsion in the bulk of the alloy was mpaofed as the mte-determining step. Based on the P ressure-composition isotherm measurement, we concluded that the decrease in discharpeability of the annealed alloy is owing to the low and flat pressure plateau, as well as the large hysteresis, but the hydrgen stomge density almost remains unchangeable after annealing.
关键词:
AB_2
,
null
,
null
,
null
,
null
,
null
雷纯鹏
,
吴爱华
,
唐建成
,
刘刚
稀有金属材料与工程
研究了两步碳化工艺对氢还原/碳化制备的纳米WC粉末及其WC-Co合金性能的影响.结果表明,WC粉末的晶粒聚集和异常粗大颗粒主要是由于碳化初期钨颗粒因烧结合并增粗,而钨粉碳化不完全主要是由于碳化后期的温度偏低,利用先低温碳化后高温碳化的两步碳化工艺不仅能够有效抑制纳米颗粒烧结合并增粗,而且可以使钨粉充分碳化,得到颗粒细小、均匀,W2C含量极少的WC粉末;采用1120℃碳化加1180℃碳化的两步碳化工艺制备出的138 nm的WC粉末,W2C含量少于0.5％(质量分数),以其为原料制备的WC-Co烧结体显微组织结构均匀,为超细晶硬质合金,综合性能优良,洛氏硬度HRA高达93.7,抗弯强度高达4380MPa.
关键词:
形貌结构
,
纳米W
,
纳米WC
,
均匀性
,
两步碳化
唐建成
,
雷纯鹏
,
刘刚
,
吴爱华
稀有金属材料与工程
研究了在传统氢还原工艺制备纳米碳化钨粉末过程中不同氧化钨的形貌结构对纳米W/WC粉末均匀性的影响,并对粉末及其WC-Co烧结体的性能进行了表征.结果表明,用具有疏松、多孔形貌结构的细小氧化钨颗粒更容易制备出结构较疏松、分散性较好的纳米W粉和WC粉.晶粒聚集和异常粗大颗粒的产生,主要与碳化过程中团聚纳米钨粉颗粒因烧结合并增粗有关.
关键词:
氧化钨
,
形貌结构
,
纳米W
,
纳米WC
,
均匀性
