TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY OF PURE SILICA MEL AND MFI ZEOLITE THIN FILMS
TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY OF PURE SILICA MEL AND MFI ZEOLITE THIN FILMS
复制标题
纯二氧化硅和 MFI 沸石薄膜的温度依赖性热导率
DOI：
10.1115/mnhmt2012-75154
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发表时间：
2012
影响因子：
3.2
通讯作者：
Laurent Pilon
中科院分区：
文献类型：
--
作者：
Thomas Coquil;Christopher M. Lew;Yushan Yan;Laurent Pilon
本文报道了在30 ~ 315 K温度范围内，用3 w法测量了纯硅沸石（PSZ）MFI和MEL薄膜的横面热导率随温度的变化。PSZ MFI薄膜是b-取向的，完全结晶的，并且具有33%的微孔率。PSZ MEL薄膜由嵌入非均匀多孔二氧化硅基质中的MEL纳米颗粒组成。它们的特征在于孔隙率、相对结晶度和粒径分别为40%至59%、23%至47%和55至80 nm。尽管具有结晶度，但由于微孔对声子的强烈散射，MFI薄膜的热导率仍小于无定形伊卡的热导率。此外，相对结晶度和粒径的增加对MEL薄膜的热导率的影响被同时增加的孔隙率所补偿。最后，采用基于德拜近似的Callaway模型对MFI沸石的热导率进行了预测和讨论。
This paper reports the temperature dependent cross-plane thermal conductivity of pure silica zeolite (PSZ) MFI and MEL thin films measured using the 3w method between 30 and 315 K. PSZ MFI thin films were b-oriented, fully crystalline, and had a 33% microporosity. PSZ MEL thin films consisted of MEL nanoparticles embedded in a non-uniform and porous silica ma- trix. They featured porosity, relative crystallinity, and particle size ranging from 40% to 59%, 23% to 47%, and 55 to 80 nm, respectively. Despite their crystallinity, MFI films were found to have thermal conductivity smaller than that of amorphous sil- ica due to strong phonon scattering by micropores. In addition, the effects of increased relative crystallinity and particle size on thermal conductivity of MEL thin films were compensated by the simultaneous increase in porosity. Finally, thermal conductivity of MFI zeolite was predicted and discussed using the Callaway model based on the Debye approximation.