The variation with current and inductance of metal transfer between contacts of palladium and silver

The work on transfer between platinum contacts, published by one of the authors in previous papers, has been extended to palladium and silver. Curves of the net transfer in 6-volt d.c. circuits are given for currents of a few amperes and inductances ranging from less than 0.1¿H up to 110¿H. Some measurements have also been made in 12 and 24-volt circuits for palladium. The general nature of the transfer for palladium is both qualitatively and quantitatively similar to that for platinum, but in the case of silver, neither residual nor reversed short-arc transfer has been demonstrated. Theoretical analysis of the results shows that the quantity determining transfer in an inductive circuit is the ratio of the charge passed in the arc to the volume of residual transfer at the same break current. Under conditions of constancy of this ratio, transfer is found to be proportional to the square of the break current up to 6.5 amp.