Corrosion Resistance Comparison of Titanium and Other Metals

Titanium exhibits excellent resistance to both general and localized corrosion in neutral, oxidizing atmospheres, and in reducing environments where corrosion inhibitors are present. Although titanium can be corroded by strong reducing acids or chromates, it remains stable in weakly reducing media. Moreover, titanium maintains good corrosion resistance even at elevated temperatures. Therefore, titanium is widely used in corrosive environments such as high-temperature salts, wet chlorine gas, nitric acid, and acetic acid. The superior corrosion resistance of titanium is attributed to the formation of a stable passive film on its surface, which can be easily regenerated in oxidizing environments even if it is damaged. Titanium remains in a passive state in both still and fast-flowing seawater, even when it contains a large amount of sediment. After five years of testing in seawater flowing at 1 m/s, the corrosion rate of titanium was only 0.00076 μm/a; even at a flow rate of 20 m/s, the corrosion of titanium in seawater is negligible. The excellent seawater corrosion resistance of titanium and its alloys, along with their high specific strength and good specific toughness, make them important materials in the fields of shipbuilding and marine engineering. The good corrosion resistance of titanium alloys enables them to maintain normal use under various corrosive conditions, allowing for co-design with the overall structure for the same service life, reducing maintenance costs, and enhancing service capabilities. At the same time, it can reduce the design allowance for corrosion, significantly reducing the structural weight of equipment. No coating protection is required, simplifying the equipment manufacturing process and effectively reducing manufacturing costs.

Compared with other metals, titanium alloys have superior seawater corrosion resistance. As shown in Table 1, the annual corrosion rate of titanium alloys in marine atmospheres is 0, while aluminum alloys and stainless steel, among others, show varying degrees of corrosion.

Table 1 Annual Corrosion Rates of Different Metal Materials in Marine Atmosphere