Electromotive force for solid-flame combustion of heterogeneous systems in loose and pressed states

By an example of condensed 3Zr + 2WO$_3$ and Al + Ni systems, it is demonstrated that the electromotive force of solid-flame combustion measured by probing in loose systems is significantly higher than that in the same systems in a pressed state. An explanation for this phenomenon is offered, based on the difference in electrical conductivity in different zones of the combustion wave in loose and pressed condensed systems.