On the influence of non-protective CuO on high-temperature oxidation of Cu-rich Cu-Ni based alloys

Journal Article · Wed Dec 01 04:00:00 EST 1999 · Oxidation of Metals

DOI:https://doi.org/10.1023/A:1018860015645· OSTI ID:684334

Haugsrud, R ^[1]

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1. Univ. of Oslo (Norway)

A number of copper-rich Cu-Ni alloys were oxidized from 750 to 1,000 C at different oxygen pressures. The oxide scales formed consist of an outer copper oxide layer and an inner porous layer where internal oxide-derived NiO particles are dispersed in a copper oxide matrix. The copper oxide may be both single-phase CuO and a two-phase (CuO + Cu{sub 2}O). At the lower part of the temperature range, the oxidation kinetics and oxide morphology depend strongly upon the formation of CuO. The CuO layer is nonprotective and further oxidation of Cu{sub 2}O, forming CuO, therefore changes the oxidation from being approximately parabolic to having a breakaway-like behavior. The relative thickness of nonprotective CuO increases with increasing NiO and reflects that the solid-state flux of copper across the Cu{sub 2}O decreases due to a barrier effect of the NiO particles and porosity in the oxide and NiO particles in the alloy. The beneficial effect of Ni in reducing the oxidation rate is lost due to the extensive formation of nonprotective CuO.

• OSTI ID: 684334
• Journal Information: Oxidation of Metals, Journal Name: Oxidation of Metals Journal Issue: 5-6 Vol. 52; ISSN OXMEAF; ISSN 0030-770X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COPPER ALLOYS
KINETICS
NICKEL ALLOYS
OXIDATION
OXYGEN
PRESSURE DEPENDENCE
SCALING
TEMPERATURE DEPENDENCE