The Electrodeposition of Aluminium

Abstract

SummaryThe electrodeposition of aluminium from electrolytes of the following compositions has been studied:—(1) AlCl3 10·38 wt %, formamide 81· wt %, nitrobenzene 5·63 wt %, benzoyl chloride 2·89 wt %, and (2) A1C13 36·7 wt %, n butylamine 12–28 wt %, diethyl ether 51·02 wt %. The formamide bath was difficult to operate and did not give satisfactory deposits of aluminium at 50°. Good deposits of aluminium up to at least 0·004 in thick were obtained from the amine-ether bath at current densities up to 90 A/ft2 at 20°. Electrolytes of identical composition and method of preparation, however, gave variable results and some coatings were highly stressed and partially exfoliated. The results in the formamide system are difficult to explain in view of the reported successful work of Holland1 and of the extreme purity of the reagents and the extensive care taken to maintain anhydrous conditions in the present work. Although the results obtained in the amine-ether system are broadly in agreement with those of Mur...