EFFECT OF A TRACE OF WATER AND SOLID LIF ON ANODE EFFECT IN THE KF2HF MELT

The effect of a trace of water and solid LiF in KF2HF melt on anode effect has been investigated. When the melt contained a relatively large amount of water, anode effect was easily caused by the formation of graphite fluoride film on anode surface, independently of whether LiF was present in the melt or not. The effect of solid LiF suspended in the melt first appeared when the water content in the melt was decreased to less than 0. 02% by pre-electrolysis. Under this condition, it took much more time for anode effect to happen, even in the melt without LiF, because the formation of graphite fluoride film was difficult and the electrochemical intercalation of HF//2** minus in graphite occurred.