Patent ID: 8404090
Filing Date: 2013-03-26
Classification: C25C

Abstract:
1. A multi-layer cathode block for an electrolytic cell having at least a surface layer having a surface expansion index and a second layer having a second expansion index: the surface layer including a surface wetting agent in a first total amount; and the second layer including a wetting agent in a second total amount, the surface layer being directly superposed to the second layer and configured to form a surface in contact with molten aluminum in the electrolytic cell, the wetting agent in the second layer including metal boride precursors that are configured to react together to generate a metal boride component in situ when the cathode block is exposed to start-up and operation conditions of the electrolytic cell, the second total amount being lower than the first total amount, and selected so as to minimize the difference between the surface expansion index and the second expansion index.