In severe corrosive or abrasive environments, steel is rarely used since the range of properties available, in existing steels, are insufficient, resulting in the prevalent usage of either corrosion resistant materials like nickel based superalloys or abrasion resistant materials like tungsten carbide based hardmetals. Recently, a host of carbide based alloys including WC-Co-Cr, NiCr-Cr 3 C 2 , WC-WB-Co etc. have been developed in an attempt to bridge the gap between providing both wear and corrosion protection. Data will be presented showing how a newly developed steel coating, SAM2X5, with an amorphous / nanocomposite structure can bridge the gap between conventional metallic alloys and ceramic hardmetal performance with excellent combinations of properties including corrosion resistance superior to nickel base superalloys in seawater / chloride environments and wear resistance approaching that of tungsten carbide. The unique combination of damage tolerance developed should be especially applicable for the replacement of electrolytic hard chromium coatings.

In the materials world, there are two distinct usages of the term nanotechnology; Particulate Materials Nanotechnology (PMN) and Bulk Materials Nanotechnology (BMN). Both approaches have been used in attempts to produce nanoscale coatings with characteristic length scales from 10 to 100 nm. While particulate strategies are widespread, a different approach is presented which focuses on producing coatings through a solid / solid state transformation which results in the refinement of the microstructural scale (i.e. phase / grain size) down to the nanoscale regime. The essential features of BMN are the 2-d grain and phase boundary defects and achieving this nanoscale regime is key to enhancing bulk properties. This paper will attempt to clarify the terminology, definitions, and usages of the term nanoscale to clear up misconceptions and clearly show the salient features allowing for the production of nanoscale microstructures on an industrial scale. A clear demonstration of this achievement will be presented with a case study on the formation of amorphous / nanocomposite coatings while processing in air using off the shelf thermal spray technology using conventionally sized feedstock. Examples of nanostructured HVOF and wire-arc as-sprayed and heat treated coatings with average phase sizes of 50 nm and 80 nm respectively will be presented using detailed TEM micrographs.