The introduction of tantalum capacitors with very high capacitance into the market is hindered by a potential thermal runaway of these devices in case of failure. To partially overcome this problem we have studied the mechanism of thermal runaway and developed tantalum powders which show a higher ignition threshold. Thermal runaway in tantalum capacitors is due to a low thermal conductivity of the anode body. We have used the laser flash method to study the thermal conductivity and the ignition threshold of different high CV tantalum powders. We will show in this paper that inter-agglomerate bonding within the anode is the bottleneck for thermal conductivity and that is possible to increase the strength of this bonding without losing the specific surface area of the anode.
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