Patent ID: 7425255
Filing Date: 2008-09-16
Classification: C25D,Y10T

Abstract:
1. A method for depositing an alloy of a system comprising at least two elements, one of which being most electro-active and at least one of which being a metal, an alloy deposit having a first layer region having a nanocrystalline structure with a first average grain size, and adjacent said first layer region, and in contact therewith, a second layer region having a nanocrystalline structure with a second average grain size, which second size differs from the first size, the method for depositing comprising the steps of: a. providing a liquid comprising dissolved species of at least two elements of the system, at least one of which elements is the metal and at least one of which elements is the most electro-active; b. providing a first electrode and a second electrode in the liquid, coupled to a power supply configured to supply electrical potential having periods of positive polarity and negative polarity at different times; c. driving the power supply for a first period of time to achieve the first specified grain size alloy deposit of the at least two elements at the second electrode, with a non-constant electrical potential having positive polarity and negative polarity at different times, which times and polarities characterize a first Polarity Ratio, which has been selected with reference to a constitutive relation that relates the first specified average grain size alloy deposit to the first polarity ratio; and; d. driving the power supply for a second period of time to achieve the second specified grain size alloy deposit at the second electrode, with a non-constant electrical potential having positive polarity and negative polarity at different times, which times and polarities characterize a second Polarity Ratio that differs from the first Polarity Ratio, the second polarity ratio having been selected with reference to a constitutive relation that relates the second specified average grain size alloy deposit to the second polarity ratio.