Prakt. Met. Sonderband 46 (2014) 157 
PRODUCTION AND ANALYSIS OF POROUS METAL 
SUPPORTS FOR A SOLID OXIDE FUEL CELL 
H. Gschiel, C. Gierl-Mayer, H. Danninger 
Technische Universität Wien, Getreidemarkt 9/164, 1060 Wien; 
harald.gschiel@tuwien.ac.at 
ABSTRACT 
The Solid Oxide Fuel Cell is characterized by a very high electrical efficiency and the 
highest efficiency in combined heat and power units. One of the major drawbacks of an 
SOFC is the longtime stability. In order to have mechanical stability, the cell can be 
supported by a so-called porous metal support, and these supports are usually 
manufactured by tape casting. In contrast, this work is focused on processing these 
porous metal supports by different powder metallurgical techniques such as the press- and 
sinter route, gravity sintering or metal injection molding. The characterization of these 
highly porous materials needs special metallographic techniques which allows to compare 
the porosity (as well as the distribution of the pores) of the different samples. For the 
gravity sintered sample (42% porosity) and the sample produced by MIM (26.5% porosity) 
the pores are homogeneously distributed and only slight agglomeration of pores can be 
seen. Also porosity quantification by image analysis has been carried out for the samples. 
1. INTRODUCTION 
The operating temperature of Solid Oxide Fuel Cells (SOFC) is typically between 800 and 
1000°C, and fuel (e.g. pure Hy) and air (or pure O,) are fed as gases. The oxygen 
molecules in the air take up electrons and, as negatively charged ions, move through the 
electrolyte to the anode where they react with hydrogen to form water (vapor). The mode 
of operation of an SOFC can be seen in Fig.1, and the electrolyte is a solid. non-porous 
metal-oxide, usually Y>O3-stabilized ZrO. [1,2]. 
In order to get mechanical stability, the cell can be supported either by the electrolyte, the 
electrodes or by a porous metal support. In case of a metal-supported fuel cell (MS-SOFC) 
a thin film cell is deposited on top of this metal support. The load bearing part of the MS- 
SOFC, is e.g. a highly porous Fe26Cr alloy and has a thickness of about 1 mm [3]. 
Significant cost reduction is thus possible since the bulk of the material can be composed 
of inexpensive material, and the metal-supported design allows conventional metal joining 
techniques such as brazing and welding [4].