STUDY OF TENSILE STRESS GENERATED BY DEZINC LAYER DURING CORROSION FOR BRASS
黄铜静态腐蚀脱Zn层引起拉应力的研究

The stress state in the dezinc layer for brass due to free corrosion was investigated. The top end of foil brass sample with one side protected, was fixed. The free end bent towards corrosion surface gradually during corrosion in 1 mol/L NH 4OH+5g/L CuCl 2 solution, when the dezinc layer was formed. The deflection of the free end was measured. The loose dezinc layer was studied by SEM, and its thickness was measured. The stress state at the interface of dezinc layer/substrate was calculated. The results showed that a tensile stress was developed at the alloy/dezinc layer interface, which was 23.4 MPa, about 1/5 of yield strength for brass. It is possible that this additional tensile stress will assist the applied stress to facilitate dislocation emission and motion, and enhance micro\|crack nucleation for stress corrosion cracking.