High temperature corrosion behavior of Cu-20Co-30Cr alloys with different grain size

摘要

The corrosion behavior of Cu-20Co-30Cr alloys with different grain size was investigated at 700-900 ℃ in 0.1 MPa pure oxygen. The corrosion rates of fine-grained MACu-20Co-30Cr alloy are significantly lower than those of coarse-grained PMCu-20Co-30Cr alloy. PMCu-20Co-30Cr alloy forms the external scales of Cu oxides followed by an internal oxidation region containing alloy and a mixture of Cu. Co and Cr oxides as well as their complex oxides. MACu-20Co-30Cr alloy forms the continuous scales of chromia and a Cr-depleted layer occurs beneath the scales. The grain refinement is helpful to form the continuous scales of chromia in a Cu-Co-Cr alloy.