Bipolar wave current, is used to electrodeposit a nanocrystalline grain size. Polarity Ratio is the ratio of absolute value of time integrated amplitude of negative and positive polarity current. Grain size can be controlled in alloys of two or more components, at least one of which is a metal, and at least one of which is most electro-active. Typically, the more electro-active material is preferentially lessened during negative current. Current density, duration of pulse portions, and bath composition are determined with reference to relations showing grain size as a function of deposit composition, and deposit composition as a function of Polarity Ratio, or a single relation showing grain size as a function of Polarity ratio. A specified size can be achieved by selecting a corresponding Polarity Ratio. Coatings can be layered, each having an average grain size, which can vary layer to layer and also graded through a region.