TAN Aichun P/M Research Institute
,
Central-South University of Technology
,
Changsha
,
China.
材料科学技术（英文）
The synthesis kinetics of YBa_2Cu_30_x supercon- ductor was studied through comparing the calcina- tion (sintering) processes of different kinds of powders. It was shown that the temperature of synthesis of YBa_2Cu_30_x phase can be lowered from 950℃ to 800℃ through direct calcination of multiphase powder with uniform chemical com- position. The stress which is caused by the volume change during synthetic reaction breaks the particles. It facilitates the formation of highly active superfines of superconductor.
关键词:
High T_c superconductor
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null
,
null
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null
齐召庆
,
汪宏涛
,
薛明
功能材料
doi:10.3969/j.issn.1001-9731.2016.02.010
采用改进的非接触式混凝土收缩测定仪及标靶,研究了m(M)/m(P)比值(MgO与KH2PO4的质量比)对磷酸镁水泥石自收缩行为的影响,运用八通道微量量热仪、压汞仪、X射线衍射仪、扫描电子显微镜及能谱仪等分析手段,分析了m(M)/m(P)比值对磷酸镁水泥石自收缩的作用机理.结果表明,磷酸镁水泥石的自收缩呈现出3个阶段的特征,即早期的迅速收缩阶段、微膨胀阶段、收缩缓慢发展阶段.随着m(M)/m(P)比值的增大,由于磷酸镁水泥石的水化放热量降低,水泥石内部孔隙率增大,水化产物结晶度降低,水泥石结构疏松,所以,自收缩率减小.
关键词:
磷酸镁水泥
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自收缩
,
m(M)/m(P)比值
F.J. Liu
,
M.C. Zhang
,
J.X. Dong
,
Y.W. Zhang
金属学报(英文版)
High temperature oxidation behaviors of FGH96 P / M superalloy have been studied in air at temperatures ranging from 600 to 1000℃. By means of isothermal oxidation testing, X-ray
diffraction, SEM (scanning electron microscopy) and EDS (energy dispersive X-ray spectroscopy) analyses, the oxidation kinetics as well as the composition and morphology of scales were investigated. Thermodynamic calculations were used to explain the oxidation mechanism. The results showed that as the oxidation temperature increased, the oxidation rate, the scale thickness and scale spallation increased. FGH96 P / M superalloy exhibits good oxidation resistance at temperature below 800℃. The oxidation kinetics follows an approximately parabolic rate law, and the
oxide layer was mainly composed of Cr2O3, TiO2, and a little amount of NiCr2O4. The oxidation is controlled by the transmission
of chromium, titanium, and oxygen through the oxide scale.
关键词:
FGH96 P/M superalloy
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null
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null
类伟巍
,
沈龙海
,
刘丹
,
李雪飞
,
彭刚
,
崔启良
,
邹广田
无机材料学报
doi:10.3724/SP.J.1077.2007.00400
采用直流电弧法使金属钽和氮气直接反应制备出了TaN纳米粉．利用XRD、XPS、TEM等测试方法对所制备的TaN纳米粉进行了表征．结果表明: 所制备的纳米粉为单一的立方相TaN, 纳米颗粒的平均粒度为5~10nm．实验中还发现氮气的气压对制备纯立方相TaN具有关键性作用, 并讨论了立方相TaN的形成机理．
关键词:
立方相TaN
,
nanocrystallites
,
dc arc discharge method
类伟巍
,
沈龙海
,
刘丹
,
李雪飞
,
彭刚
,
崔启良
,
邹广田
无机材料学报
doi:10.3321/j.issn:1000-324X.2007.03.004
采用直流电弧法使金属钽和氮气直接反应制备出了TaN纳米粉.利用XRD、XPS、TEM等测试方法对所制备的TaN纳米粉进行了表征.结果表明:所制备的纳米粉为单一的立方相TaN,纳米颗粒的平均粒度为5～10nm.实验中还发现氮气的气压对制备纯立方相TaN具有关键性作用,并讨论了立方相TaN的形成机理.
关键词:
立方相TaN
,
纳米粉
,
直流电弧法
Yong LIU
,
Baiyun HUANG
,
Kechao ZHOU
,
Hongwu OUYANG
,
Yuehui HE
材料科学技术（英文）
In order to overcome the shortcomings of conventional hot pressing, a novel near net-shape technique, called radial hot pressing, for P/M parts with large height-to-diameter (H/D) ratio was introduced. Effects of processing parameters on the microstructures and density of P/M TiAl base alloy valves were studied. Results show that the radial hot pressing is an effective technique for manufacturing valves with a H/D ratio of about 10:1, and the perfect joint interface between the Mo sheet and the parts is helpful for subsequent HIPing.
关键词:
Near net-shape technique
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null
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null
