Titanium-8 percent manganese, titanium-5 percent aluminum-2½ percent tin, titanium-2 percent aluminum, titanium-6 percent aluminum, titanium-1 percent copper, and titanium-5 percent copper alloys are similar to commercially pure titanium in chemical and galvanic corrosion properties. These alloys are completely resistant to corrosion in synthetic ocean water, tap water, 1 percent sodium hydroxide, and 5 percent ferric chloride solutions. In sulfuric acid solutions saturated with air, the titanium alloys with the exception of those containing copper are resistant to corrosion in 5 percent solution at 35 C but corrode rapidly in 10 percent solution. At 60 C, these alloys are inert in 1 percent and corrode in 5 percent acid. The titanium-copper alloys usually are more resistant than commercially pure titanium to corrosion in sulfuric acid solutions and less resistant in hydrochloric acid. In contact with aluminum in 0.5 percent sulfuric acid saturated with air, titanium and the titanium-base alloys are the cathodic members of the couples. Titanium and titanium-base alloys are generally anodic when in contact with stainless steels in air-saturated 4.7, 9.3 and 17.5 percent sulfuric acid solutions but the galvanic corrosion rates are low. Furthermore, the chemical corrosion of titanium alloys is almost eliminated as a result of contact with stainless steel. 6.3.15
Corrosion Resistance of Titanium Alloys Compared With Commercially Pure Titanium
DAVID SCHLAIN—Chemical engineer, Bureau of Mines, U. S. Department of Interior, Region V, Division of Mineral Technology, College Park, Maryland. He received BS and MS degrees from University of Pennsylvania and a PhD in chemical engineering from University of Maryland. His research interests include process metallurgy, electrode-position, passivity and corrosion phenomena, applications of ultrasonics to metallurgy. He is a member of American Chemical Society, Electrochemical Society, and American Society for Metals.
CHARLES B. KENAHAN—Chemist, Bureau of Mines, U. S. Department of Interior, Region V, Division of Mineral Technology, College Park, Maryland. He received a BS in chemistry from Kings College in 1950. From 1951 to 1953 he was employed by the Battery Section of the Naval Ordnance Laboratory, and from 1953 to 1955, he conducted an investigation of the corrosion properties of titanium and zirconium for the Bureau of Mines. At present, Mr. Kenahan is engaged in the application of ultrasonics to metallurgical problems.
