INFLUENCE OF SEGREGATION DIFFUSION-PROCESSES ON THE EFFECTIVE THERMAL-CONDUCTIVITY OF POROUS CERAMICS

被引：13

作者：

GAMBARYAN, T

LITOVSKY, EY

SHAPIRO, M

机构：

[1] Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa

来源：

INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER | 1993年 / 36卷 / 17期

关键词：

D O I：

10.1016/0017-9310(93)90074-G

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

A model of heat transfer in porous ceramics in the presence of segregation-surface diffusion mechanism is proposed. The effective thermal conductivities of materials possessing a small amount of spherical or cylindrical pores are calculated, which are shown to generalize the Maxwell formula for conductivities of composite materials. Nondimensional parameters are formulated which govern the relative influence of segregation and diffusion of impurities on the effective conductivity of porous materials. Estimates performed for Arrhenius and McLean surface isotherm formulas show that the segragation-diffusion mechanism satisfactorily describes abnormal temperature dependences of thermal conductivities of refractory oxides in vacuum.

引用

页码：4123 / 4131

页数：9

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