Vibration-enhanced Corrosion of Metals

Abstract

THE influence of mechanical energy on the chemical reactivity of solids provides a fruitful area of research which touches on many subjects of technological importance. Even in such obvious examples as stress and fretting corrosion little emphasis has been placed in published work on the precise contribution of the mechanical component of the phenomena. On the other hand, in most investigations of cavitation damage, where high mechanical stresses are produced momentarily in a solid when cavitation bubbles collapse at the surface, the techniques that are most suitable for laboratory testing (that is, magnetostrictive vibration or transducer ring) lead to a gross magnification of the mechanical damage relative to any electrochemical effects that may be operative. While such methods may be satisfactory for comparing the susceptibility or resistance of materials to cavitation erosion, they do not readily permit conclusions as to environmental effects in vibrating or cavitating conditions. From recent work of Ozevor¹, it is clear that ultrasonic vibrations can have profound effects on electrochemical reactions, but there is little evidence of vibration-induced changes for frequencies less than about 10 kc/s.