Influence of applied stress on cracking and spalling of oxide film at room temperature

The cracking and spalling behavior of the oxide film under applied stress at room temperature was studied. The critical applied stress of oxide film cracking and spalling was calculated. By dynamic tension experiments of oxide film on A3 steel and LY12CZ aluminium alloy, the existence of critical applied stress of oxide film cracking and spalling was proved. The different cracking and spalling behavior of two kinds of oxide film was also compared. The electrochemical behavior of oxide film cracking and spalling in 3%NaCl solution was studied, according to the variety of open circuit potential of two kinds of materials under applied stress. The sharp drop in the open circuit potential proved the existence of applied stress too. Finally electrochemical impedance spectroscopy (EIS) measurement of oxide film with and without cracks was carried out.