万帅
,
吕文中
无机材料学报
doi:10.3724/SP.J.1077.2010.00157
研究了锌硼玻璃掺杂量对低压ZnO压敏电阻微观结构和电性能的影响. 结果表明, 当掺杂量x=0.1wt%时, 可以得到较好综合性能的ZnO压敏电阻：E1mA＝36.7V/mm, α=30.4, IL=0.1μA. 并应用晶粒生长动力学唯象理论研究了锌硼玻璃掺杂低压ZnO压敏电阻的晶粒生长规律, 探讨了锌硼玻璃掺杂对低压ZnO压敏陶瓷晶粒生长的作用机理. 当烧结温度T≤1000℃时,其晶粒生长动力学指数n≈4.54, 激活能Q≈316.5kJ/mol, 这是由于未熔融的锌硼玻璃通过颗粒阻滞机理阻碍了ZnO压敏陶瓷晶粒的生长; 而当T>1000℃时, 其晶粒生长动力学指数n≈2.92, 激活能Q=187kJ/mol, 这是由于熔融的锌硼玻璃通过液相烧结机理促进了晶粒的生长.
关键词:
锌硼玻璃
,
varistor
,
electrical properties
,
kinetic exponent
,
apparent activation energy
司伟
,
王晶
,
王修慧
,
高宏
,
翟玉春
无机材料学报
doi:10.3724/SP.J.1077.2011.00726
在超声波作用下以均匀沉淀法合成了纳米荧光粉Eu0.12Y1.78Ca0.10O3-δ, 用X射线衍射仪(XRD)、能谱分析仪(EDS)、等离子体原子发射光谱(ICP-AES)、透射电镜(TEM)对其进行表征, 利用不同升温速率的差热-热重分析(DTA-TG)研究了纳米荧光粉Eu0.12Y1.78Ca0.10O3-δ的合成动力学. 研究表明, 合成的Eu0.12Y1.78Ca0.10O3-δ为体心立方Y2O3结构, 球形纳米多晶, 平均粒径约20nm, 其前驱体为六方相Y(OH)3, 利用Doyle-Ozawa法和Kissinger法计算得到前驱体三个分解阶段的表观活化能平均值分别为102.06、488.00、302.74kJ/mol. 用Kissinger法确定了反应级数和频率因子, 确定了三个反应阶段的速率方程分别为dα/dt=8.86×108e-12280/T(1-α)1.36; dα/dt=4.05× 1033e-58700/T(1-α)1.32; dα/dt=7.14×1019e-36410/T(1-α)1.27.
关键词:
纳米荧光粉
,
kinetics
,
apparent activation energy
YAO Daping HU Zhuangqi LI Yiyi ZHANG Yun and SHI Changxu Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
110015
,
China.
材料科学技术（英文）
In this paper,the activation energy for precipi- tate dissolution in binary AI-Li alloy has been in- vestigated by considering precipitate dissolution in Al-Li alloy,continuously heated as a thermally ac- tivated process.The proposed calculation was car- ried out by changing the scanning rate in DSC measurement.The results show that the formation of GP zone is easy because the activation energy for its dissolution is smaller than that for Li atom diffu- sion in the matrix.The δ′dissolution consists of two steps:the first step needs larger thermal activation to break down the superlattice structure,and the second is much easier like GP zone dissolution.The phase is the most stable,which needs much larger thermal activation to disappear.
关键词:
Al-Li alloy
,
null
,
null
,
null
