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The development of Titanium alloys occurred in the early 1950s primarily for critical aerospace applications which required materials with high strength-to-density ratios. In addition to the advantages afforded the aerospace industry, titanium has become widely recognized for its resistant to many highly corrosive environments common to industrial applications.
Ti Squared Technologies’ net shape capability makes many titanium alloys available as standard engineering materials in applications where high strength coupled with corrosion resistant properties are critical and desirable.
Titanium alloys naturally form a very stable and highly protective oxide film on metal surfaces resulting in excellent corrosion resistance. This beneficial oxide film occurs because titanium metal is highly reactive and has an extremely high affinity for oxygen. The oxide film forms spontaneously and instantly when fresh metal surfaces are exposed to air and/or moisture. If the oxide film is somehow removed, it can reheal itself instantaneously in the presence of trace amounts of oxygen or water. The presence of alpha case in titanium castings helps to inhibit corrosion even in oxygen free environments. Ti Squared produces net shapes that perform effectively in the harshest of environmental conditions.
Titanium alloys are not impervious to all corrosive environments. For example, in the absence of a source of oxygen, anhydrous conditions may cause titanium corrosion, preventing protective film regeneration once damage has occurred.
Typical corrosion of ferrous materials
In addition, aqueous solutions of reducing acids such as Hydroflouric Acid (F) will aggressively attack titanium . However, titanium is inert to most aqueous environments in nature since the oxide, typically TiO2, forms an impenetrable barrier against attack. Oxidation can also occur when titanium alloys are exposed to high-temperatures in the presence of oxygen. This oxidation tends to promote the formation of the chemically resistant, highly crystalline form of TiO. These oxygen films are invisible to the eye and will grow to a depth of 0.005” depending upon exposure time. The oxide is highly chemically resistant and is attacked by very few substances, including hot, concentrated HCl, H2SO4, NaOH and hydrogen.
The corrosion resistance of titanium can be much improved by alloying with elements such as Palladium, Nickel and Molybdenum. These additions cause cathodic depolarization by shifting alloy potential in the noble direction. Depending upon the level of alloy addition, resistance of titanium can be improved even in reducing acid media.
Ti Squared makes net shape castings from several commercially available titanium alloys, including the titanium-palladium alloys (grades 7 and 11). These alloys all offer a unique combination of high strength, low density, and superior corrosion resistance.
Fig 1. Corrosion of dissimilar metals coupled to titanium in flowing ambient-temperature seawater
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