Causes and formation of corrosion of titanium rods
Most of us think that titanium and titanium alloy products will not corrode easily, but titanium alloy rods often corrode. What's going on here? Below I will briefly introduce the causes and main types of back corrosion of titanium rods. Everyone can avoid corrosion of titanium rods during use.
1. Crevice corrosion: Crevice corrosion is a localized characteristic that occurs in tight crevices. Cracks and gaps can be caused by structural surfaces (such as flange joints or gasket surfaces, connections between pipes and tubesheets, bolts or rivets, etc.), or they can be caused by sediment encrustation or coating. In the early days, it was generally believed that titanium would not suffer from crevice corrosion in seawater and salt spray anyway. Subsequently, it is used to suppress oxidant consumption in high-temperature chloride media (such as seawater heat exchangers) and wet chlorine (such as wet chlorine tube condensers), hydrochloric acid corrosion devices, formic acid corrosion, oxalic acid corrosion devices and other media. Media and crevice corrosion hardware hazards and damage continue to occur.
Crevice corrosion of titanium rods is related to many variables such as temperature, chloride type and immobility, pH, and pore size and calculations. In addition, holes made of titanium and non-metallic materials such as PTFE, titanium and asbestos are more susceptible to crevice corrosion than holes made of titanium and titanium.
2. Pitting corrosion: Pitting corrosion is a new type of consumption of passivated metal. Titanium's resistance to pitting corrosion is generally excellent compared to hardened steel or aluminum compounds. As the utilization rate of titanium in high-temperature concentrated chloride devices continues to increase, the amount of titanium metal used in pits continues to expand.
The titanium anode hopper in the electrolytic zinc plant, the heated titanium coil in the zinc chloride plant, and the titanium ball valve in the 175°C 72% calcium chloride plant all suffered pitting damage. In general, the consumption of titanium is more troublesome than pitting corrosion, which usually occurs through pitting consumption of the crack surface.
3. Electrical consumption: Electrical consumption is a characteristic of metallic contacts (including electrical contacts) in an electrolyte arrangement. Because of differences in the metals' likelihood of consistent states, one metal can accelerate the depletion (i.e., anodic decomposition) of the other. The oxide film of titanium is very stable and is usually in the cathodic state. Electrical consumption does not accelerate the anodic decomposition of titanium.
It is worth noting that titanium retains hydrogen in the cathodic state and eventually causes hydrogen embrittlement, so it is important to prevent accelerated consumption of coupling metals (such as aluminum, copper, zinc, etc.). The level of metallic galvanic consumption depends on the difference in continuity of coupled metallic galvanic couples in the medium.
