Corrosion Resistance of Industrial Pure Titanium and its Alloys under High Temperature and Different Cooling Methods

Industrial pure titanium (TA2) and Ti-6Al-4V (TC4) have been widely available for chemical equipment. However, the corrosion resistance changes during their post-fire performance. In this research, the electrochemical properties of industrial pure titanium and Ti-6Al-4V after heat treatment and different cooling methods were analyzed by AC impedance technique and dynamic polarization method. The results support two conclusions. Firstly, when the temperature is approximate to the phase transition point, for pure titanium and its alloys, water-cooling can obtain better corrosion resistance than air-cooling. With regard to pure titanium, its best corrosion resistance can be obtained at 800°C under water-cooling. For Ti-6Al-4V, its best corrosion resistance can be obtained when the temperature reached 910 °C under water cooling condition. Secondly, the corrosion current density under acid corrosion condition has risen compared with neutral corrosion condition. These results can provide some experimental data and theoretical basis for post-fire anticorrosion performance of titanium materials, and also support the safety, risk evaluation of titanium equipment.