Acid Pickling Process of Titanium alloys and its Investigation of intergranular corrosion and Pitting corrosion

Abstract

Before fluorescence detection of Titanium alloy components, acid pickling in HF-HNO3 solutions is always required in order to remove the superficial oxides of the components. According to the relative CPS document, the conditions for Titanium alloy pickling are HF arranged below 90g/L, HNO3 300-450g/L and at ambient temperature. In this paper, the corrosion rate of the acid pickling process of TC4 alloy was investigated using the acid solutions with variable HF、Titanium contents and fixed HNO3 content of 375g/L at different temperatures. In addition, the intergranular corrosion and pitting corrosion of the TC4 alloys after pickling under different conditions were conducted. The effects of HF and HNO3 on the intergranular corrosion and pitting corrosion were discussed.