In order to quantitatively evaluate the influences of nitrogen and
The passivity is a common phenomenon for most engineering metals, especially for stainless steel, titanium and its alloy, nickel-based alloy, et al. A compact, several nanometer thickness, and highly defective passive film can automatically form on the surface of the nickel based alloys or stainless steels in the existence of oxygen , , , , , , ,  and . The passive film existing between the substrate and the aggressive electrolyte can be deemed as the ions barrier to protect the substrate from further corrosion. How does the passive film affect the cavitation erosion of the substrate? Only a few papers ,  and  study this CUDC-101 issue by using electrochemical measurement. While, there is still a disagreement about the passivity effect on the cavitation erosion . In order to better understand the role of passive film in cavitation erosion, pure titanium is immersed into 0.35%NaCl solution at room temperature with continuous bubbling oxygen and nitrogen for 3 weeks, respectively. When the bubbling time are 1 week, 2 weeks and 3 weeks, the ultrasonic cavitation erosion and the electrochemical experiments are measured using a magnetostrictive-induced ultrasonic cavitation erosion (CE) facility, scanning electron microscopy (SEM) and Mott–Schottky, respectively. The influences of oxygen and nitrogen on the composition of the passive film are detected by X-ray photoelectron spectroscopy.