School of Material Science and Technology, Nanchang Hangkong University
The effects of main solution ingredients, temperature on dissolution and characteristics of corrosion processing for Ti-6Al-4V in hydrofluoric-nitric acid system were investigated by means of E-t curve, potentiodynamic polarization curve. Moreover anodic and cathodic reaction rate measurements were used to discuss corrosion dynamics. The process of “attack→oxidation→dissolution” repeats continuously during the course of corrosion dissolution of titanium alloy in this solution system. The growth and destruction of passive film simultaneously occur. Corrosion processing rate tends to be stable when the growth of passive film and dissolution of the substrate achieve dynamic balance. At the early stage of corrosion processing, corrosion potential changes to a more positive value when the concentration of hydrofluoric acid is low, indicating that oxide film is difficult to be attacked, while in case of higher concentration, corrosion potential becomes negative quickly as oxide film is easily dissolved. Corrosion dissolution rate is affected by hydrofluoric acid concentration and temperature. With the increase of hydrofluoric acid concentration and temperature, the activation energy declines, corrosion dissolution is enhanced. Temperature plays a leading role under the condition of lower concentration of hydrofluoric acid. When the concentration reaches 80mL/L, the influence of temperature attenuates and the concentration of hydrofluoric acid becomes the major factor.
林翠.氢氟酸-硝酸体系中Ti-6Al-4V的腐蚀加工溶解特征[J].稀有金属材料与工程,2016,45(10):2628~2634.[lin cui. Corrosion Processing Dissolution Characteristics of Ti-6Al-4V in Hydrofluoric –Nitric Acid System[J]. Rare Metal Materials and Engineering,2016,45(10):2628~2634.]