摘要 |
<p>Aluminum, or an alloy thereof, is grained in a two-stage process wherein it is subjected to an electric current while immersed in an acidic electrolyte solution, such as a solution comprised of hydrochloric acid and aluminum chloride. Current density in the first stage of the process is at least as great and preferably substantially greater than in the second stage, while both treatment time and current consumption in the first stage are less than in the second stage. The process provides a fine uniform grain that is essentially free of pits and is especially beneficial for use in the manufacture of aluminum supports for lithographic printing plates.</p> |