烧结金属多孔材料的渗透和导热性能测试及孔隙特征分析

摘要：
为研究烧结金属多孔材料的各项性能参数，测试了多孔材料的孔隙率；在自然断裂表面扫描电镜（SEM）图像基础上进行图像处理与分析，得到面孔隙率以及平均孔径与孔径分布特征；设计了以达西定律为依据的实验系统对渗透系数和透气度进行测试，分析了原始粉末粒度、孔隙率、厚度、低温工况、平均孔径以及孔径分布等因素对渗透性能的影响；使用hot disk热导测试装置测量了有效热导率，并与经验公式的预测结果进行比较.结果表明，体积平均孔径与孔径分布特征能有效反映透气度的变化规律；厚度对烧结金属多孔材料的孔隙率和渗透系数有着重要影响，厚度越小，原始粉末颗粒的直径越大，壁面效应越明显；低温工况不会改变烧结金属多孔材料的渗透性能.关键词：
金属多孔材料； 烧结； 渗透系数； 孔隙率； 热导率中图分类号： TK 172
文献标志码： A

Permeability, Thermal Conductivity and the Pore Characters of Sintered Porous Metal Materials

In order to characterize the sintered porous metal materials, porosity was tested. Surface porosity, average pore size and pore size distribution were obtained through image processing and analysis based on scanning electron microscope(SEM) images of nature fracture surfaces. Permeability and air permeability were measured by experimental apparatus based on Darcy’s law, and the effects of original power grain size, porosity, thickness, low temperature condition, average pore size and pore size distribution on permeability were also discussed. Effective thermal conductivities were measured by a hot disk thermal constant analyzer and compared with predicted results from empirical equations. The results demonstrate that volume average pore size and pore size distribution can effectively reflect the change of air permeability, and thickness has an important influence on porosity and permeability. A stronger wall effect is presented in the case of a thinner thickness and a bigger original power grain size. Low temperature condition has no influence on permeability.