Cold spray deposition of WC–17 and 12Co cermets onto aluminum

The objective of this study was to deposit two wear- and corrosion-resistant WC cermet powders with distinct cobalt content (WC–17Co and WC–12Co) onto Al7075-T6 substrates using the Cold Gas Spraying (CGS) technique. WC–Co cermets show excellent mechanical and chemical properties and are thus extensively used in many industries. The addition of more ductile Co binder to the composite facilitates deposition by CGS while conferring proprieties that differ to those achieved with a WC–Co cermet with a lower content of ductile binder. XRD tests were run on the powder and coatings to identify all the present phases and determine the possible phase changes during spraying. The bonding strength of the coatings was measured by adherence tests (ASTM C633-08); the sliding (ASTM G99-04) and abrasive (ASTM G65-00) wear resistances of the coatings were also studied. Corrosion resistance was determined by electrochemical measurements. Such results were compared to the ones produced by conventional thermal spraying techniques. CGS yielded the deposition of dense and hard WC–17/12Co coatings with satisfactory tribological and electrochemical properties on aluminum alloy Al7075-T6.