The Electrodeposition of Coherent Deposits of Refractory Metals: III . Zirconium

Abstract

Exploratory experiments in chloride, bromide, and mixed chloride‐fluoride melts always produced dendritic zirconium deposits. Pure fluoride systems consisting of dissolved in alkali fluoride solvents produced coherent deposits of metal, some as thick as 0.1 in. with no indication of reaching a thickness limit, on electrolysis at 750 °C and 30 ma/cm2 cathode current density. Analysis and material balance experiments showed that reduced compounds were absent in these fluoride systems. Chronopotentiometric measurements indicate that the zirconium is deposited from the tetravalent state in a single four‐electron step which would appear to be irreversible. The addition of , , and to a working zirconium bath results in the deposition in coherent form of the compound and the alloys and . The plate was 11 mils thick and showed no evidence of reaching an upper limit of thickness, while both alloys were smooth and fine‐grained in nature, the deposit showing a particularly interesting rhythmic banded structure.