14Ö 



boundary surface has, therefore, heen only little shifted inward. When 

 the passage of the current is continued, the boundar}' surface moves 

 more inward, and when it has reached F" (r", a stationary state 



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F 



F f 



E E 

 Fig. :i 



will have been reached, in which the thicUness of the diffusion 

 laj'er and the concentration gradient of the hydrogen is stationary. 

 The former is smaller and the latter is greater tiian when the current 

 had just been started ; consequently also the hydrogen charge at the 

 boundary surface F" C" can now be greater than at first. The 

 course of the potential as function of the time will, therefore, be 

 as follows. Before the polarization the electrode is comparatively 

 active, corresponding to the hydrogen charge F C. When the current 

 is put on, the potential rises in consequence of the decrease of the 

 hydrogen charge. On continued passage of the current the potential 

 descends, again, because the hydrogen charge becomes greater again 

 in consequence of the diffusion layer becoming thinner. 



This is what was observed for the anodic polarization of electrolytic 

 chromium, and also of Got^uschmidt chromium which is activated 

 in molten ZnCl^ or KCl + NaCl. Also with chromium of Gold- 

 scHMiDT which has been activated in strong HCl, the same phenomenon 

 is observed. Nevertheless there exists quantitatively a great difference 

 between these two kinds of chromium. With electrolytic chromium 

 the activation proceeds much more quickly during the passage of 

 the current than with Goluschmidt chromium which has been 

 activated in ZnCl,, and with this again nH)re quickly than with 

 GoLDSCHMiDT cliromium that has been activated in hydrochloric acid. 

 For this last the potential continued to become more and more 

 negative for houi-s with constant strength of the current. For electro- 

 lytic chromium this continued only for a few minutes. The difference 



