Wrought Copper-Nickel-Chromium- A New Concept for a Corrosion Resistant Copper Alloy

摘要

For many decades corrosion resistant copper alloys have been utilized in sea water applications for their unique combination of properties, anti-biofouling, non-sparking, resistance to cavitation corrosion, excellent wear properties and low magnetic permeability. One disadvantage has been lack of mechanical strength and copper-nickel-chromium (CuNi30Cr2) is a unique alloy developed to overcome this. It does not rely on a precipitation hardening mechanism for increasing the mechanical properties but 'spinodal' decomposition which is a chemical strengthening mechanism. Additionally, the alloy is single phase and hence it does not suffer from dealloying (selective phase corrosion) which has been problematic with some copper based alloys in marine salt water environments. This paper evaluates the wrought version of CuNi30Cr2, which can now be manufactured to UK Defence Standard 02-886 and offers significant scope for design engineers with much higher mechanical properties, increased toughness and increased internal integrity. It provides the findings of a four year corrosion program with comparisons against 26 other alloys involving a range of copper alloys, nickel-copper, nickel alloys, titanium and super duplex and other stainless steels. Resistance to general corrosion, galvanic and crevice corrosion in a sea water environment were all examined as well as mechanical properties.