| Autor: |
Zierath, Bodo, Greil, Peter, Stumpf, Martin, Fey, Tobias |
| Předmět: |
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| Zdroj: |
Ceramic Engineering & Science Proceedings; 2016, Vol. 37 Issue 4, p149-162, 14p |
| Abstrakt: |
Cellular materials offer a wide spectrum of applications such as catalyst support structures, lightweight materials, energy adsorption, band gap material or energy storage materials. Due to several ways of processing and a wide range of material properties e.g. thermal conductivity, mechanical strength or damping measured and verified. Especially in heterogeneous structures, only global effective material properties can be easily measured and influence of microstructure on these properties is hard to determine. Common open cell ceramic foams produced by the replica technic invented by Schwarzwalder [1] provide a high porosity > 70 % [2] but low mechanical compressive strength of 0.5 MPa to 10 MPa [3][4][5] due to porosity and the hollow struts. Due to these weak mechanical properties of Al2O3 replica foams, a novel way of strength enhancement by inducing intrinsic residual stresses is shown. The residual stress was induced by different thermal expansion coefficients of mullite (5.5*10-6 K-1) and alumina (8.0*10-6 K-1). The intrinsic mullite layer of 2-6 µm thickness formed during sintering at 1700 °C. The residual stress increased the characteristic strength 0 by 100 % to 217 % depending on pore size with nearly no decrease of the porosity. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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