A method for forming a coated substrate is disclosed. The method includes
depositing an undercoating layer on a substrate; and depositing a
functional coating on the undercoating layer, the functional coating
comprising at least one material that can be present in at least two
crystal structures, wherein the at least two crystal structures are
present at and exposed surface of the functional coating, wherein the
undercoating layer comprises at least two different materials wherein a
first material at the exposed surface provides a first surface area and a
second different material at the exposed surface provides a second
surface area.